carbonate platform growth and cyclicity at a …kaufman/pdf/jiang_03.pdfcarbonate platform growth...

Carbonate platform growth and cyclicity at a terminalProterozoic passive margin, Infra Krol Formationand Krol Group, Lesser Himalaya, India

GANQING JIANG*, NICHOLAS CHRISTIE-BLICK� , ALAN J. KAUFMAN� ,DHIRAJ M. BANERJEE§ and VIBHUTI RAI–*Department of Earth Sciences, University of California, Riverside, CA 92521, USA(E-mail: [email protected])�Department of Earth and Environmental Sciences and Lamont-Doherty Earth Observatory, ColumbiaUniversity, Palisades, NY 10964-8000, USA�Department of Geology, University of Maryland, College Park, MD 20742-4211, USA§Department of Geology, University of Delhi, Delhi 110007, India–Department of Geology, Lucknow University, Lucknow 226007, India

ABSTRACT

The Infra Krol Formation and overlying Krol Group constitute a thick

(< 2 km), carbonate-rich succession of terminal Proterozoic age that crops

out in a series of doubly plunging synclines in the Lesser Himalaya of

northern India. The rocks include 18 carbonate and siliciclastic facies,

which are grouped into eight facies associations: (1) deep subtidal; (2)

shallow subtidal; (3) sand shoal; (4) peritidal carbonate complex; (5)

lagoonal; (6) peritidal siliciclastic–carbonate; (7) incised valley fill; and (8)

karstic fill. The stromatolite-rich, peritidal complex appears to have

occupied a location seaward of a broad lagoon, an arrangement

reminiscent of many Phanerozoic and Proterozoic platforms. Growth of

this complex was accretionary to progradational, in response to changes in

siliciclastic influx from the south-eastern side of the lagoon. Metre-scale

cycles tend to be laterally discontinuous, and are interpreted as mainly

autogenic. Variations in the number of both sets of cycles and component

metre-scale cycles across the platform may result from differential

subsidence of the interpreted passive margin. Apparently non-cyclic

intervals with shallow-water features may indicate facies migration that

was limited compared with the dimensions of facies belts. Correlation of

these facies associations in a sequence stratigraphic framework suggests that

the Infra Krol Formation and Krol Group represent a north- to north-west-

facing platform with a morphology that evolved from a siliciclastic ramp, to

carbonate ramp, to peritidal rimmed shelf and, finally, to open shelf. This

interpretation differs significantly from the published scheme of a basin

centred on the Lesser Himalaya, with virtually the entire Infra Krol–Krol

succession representing sedimentation in a persistent tidal-flat environment.

This study provides a detailed Neoproterozoic depositional history of

northern India from rift basin to passive margin, and predicts that

genetically related Neoproterozoic deposits, if they are present in the High

Himalaya, are composed mainly of slope/basinal facies characterized by

fine-grained siliciclastic and detrital carbonate rocks, lithologically different

from those of the Lesser Himalaya.

Keywords Cycles, facies, Infra Krol Formation, Krol Group, Lesser Himalaya,platform evolution, terminal Proterozoic.

Sedimentology (2003) 50, 921–952 doi: 10.1046/j.1365-3091.2003.00589.x

� 2003 International Association of Sedimentologists 921

INTRODUCTION

Recent studies of Precambrian carbonate rockshave demonstrated that late Archaean to Neopro-terozoic carbonate platforms are characterized byarchitecture, primary mineralogy and facies dis-tributions that are similar to those present inPalaeozoic to Recent platforms (e.g. Grotzinger,1986a, 1989a,b; Beukes, 1987; Hoffman, 1989;Sami & James, 1994; Grotzinger & James, 2000). Inthe absence of skeletal metazoans and green algaein all but the latest Neoproterozoic, stromatolitesand microbiota may have played an essential rolein the construction of wave-resistant buildups atplatform margins and in the production ofcarbonate mud, comparable to the roles of higherorganisms in Phanerozoic examples (e.g. Sami &James, 1994; Grotzinger & James, 2000). It has alsobeen shown that interpreted upward-shoalingmetre-scale units or ‘cycles’ in some Proterozoiccarbonate platforms trace laterally with consis-tent stacking patterns for tens to hundreds ofkilometres (e.g. Grotzinger, 1986b; Dehler et al.,2001), again similar to a number of purportedPhanerozoic examples (e.g. Goldhammer et al.,1990, 1993; Osleger & Read, 1991; Montanez &Osleger, 1993; Elrick, 1995; Bosence et al., 2000).

The Neoproterozoic is of special interest for thestudy of carbonate platform evolution and depo-sitional cycles. In comparison with Palaeo-proterozoic and Mesoproterozoic counterparts,preserved Neoproterozoic carbonate rocks appearto have accumulated mainly on ramps rather thanon rimmed shelves (Grotzinger, 1989b; Grotzinger& James, 2000). The reason for the predominanceof Neoproterozoic ramps is uncertain, but per-haps related to a general association in mostbasins with siliciclastic sedimentation. Few car-bonate-dominated systems of this age have beenadequately documented. A second feature of theNeoproterozoic is that it is an interval ofunusually widespread glaciation, although withsome ongoing debate about the number andtiming of ice ages, and the manner in whichdeposits correlate from one place to another(Kaufman et al., 1997; Hoffman et al., 1998; Ken-nedy et al., 1998; Crowell, 1999; Sohl et al.,1999). Metre-scale upward-shoaling ‘cycles’ arean anticipated consequence of carbonate sedi-mentation during times of glacio-eustatic change.

It is in this context that we studied thesedimentology of the Infra Krol Formation andKrol Group of the Lesser Himalaya, India, one ofthe most carbonate-rich successions of terminalProterozoic age. The primary goals of this paper

are: (1) to document details of regional faciespatterns and their implications for platformarchitecture; (2) to present examples of metre-scale ‘cycles’, their lateral variability and theirstacking patterns; and (3) to interpret the evolu-tion of the platform through time. Here, we usethe term ‘cycle’ in a purely descriptive sense forrepeated intervals of palaeowater depth changewithout implying periodicity.

GEOLOGICAL SETTING

The Infra Krol Formation and Krol Group togetherconstitute a succession of mostly fine-grainedsiliciclastic and carbonate rocks that crop outover a distance of 280 km in the Lesser Himalayaof northern India (Fig. 1; Bhargava, 1979; Shankeret al., 1989, 1993; Shanker & Mathur, 1992).These rocks are as much as 2 km thick, and areof terminal Proterozoic age (� 590–543 Ma; Jianget al., 2002). They overlie the glacial-marineBlaini Formation and underlie the predominantlysiliciclastic Tal Group (Fig. 2).

Two prevailing ideas have been published on theInfra Krol–Krol succession in the Lesser Himalaya.One is that all the sediment accumulated in a basincentred on Mussoorie syncline, where both strat-igraphic thickness and palaeowater depths havebeen interpreted to achieve maximum values(Fig. 3; Shanker et al., 1989, 1993; Shanker &Mathur, 1992). That interpretation is based onlithic correlation, which is assumed to approx-imate time correlation (Fig. 3). However, sugges-ted correlation schemes vary in detail from oneauthor to another, and the absence of anticipatedbasinal or slope facies at Mussoorie syncline castsdoubt on their validity. A second widely acceptedidea is that the Krol represents the sedimentaryrecord of a tidal flat sea that extended southwardacross the Indian Peninsula with little variation inpalaeowater depth either spatially or as a functionof time (Singh, 1980a,b; Singh & Rai, 1980; Singhet al., 1980; Bhargava & Singh, 1981; Tangri &Singh, 1982). This interpretation finds support inthe presence of locally abundant shallow-waterindicators in the rocks (microbial laminae, fenes-tral structure, gypsum casts and desiccationcracks), but it fails to account for the full range offacies present or for their systematic arrangementsin three dimensions.

Our revised interpretation, based on sequencestratigraphic analysis, is that the Infra Krol–Krolsuccession was deposited at the inner part of anorth- to north-west-facing passive continental

922 G. Jiang et al.

� 2003 International Association of Sedimentologists, Sedimentology, 50, 921–952

margin (Fig. 4; Brookfield, 1993; Jiang et al., 2002;see below). Eight regional stratigraphic disconti-nuities have been traced throughout the LesserHimalaya, including three that are interpreted assequence boundaries (surfaces 2, 4 and 5 inFig. 4). Regional facies distribution anchored inthis physical stratigraphic framework indicatesthat platform architecture evolved through time,from siliciclastic and carbonate ramps to rimmedshelf and to open shelf (Figs 5 and 6). Althoughno slope or basinal facies crop out in the LesserHimalaya, our interpretation is supported byseveral lines of evidence. First, in contrast topublished interpretations, the Infra Krol–Krolsuccession thickens gradually but consistentlytowards the north-west (Fig. 4). Previously inter-preted thinning in the vicinity of Solan and atNigalidhar syncline (Fig. 3) is due to poor expo-sure of the upper part of the Krol Group in thoseareas, and apparent thickening at Mussoorie andNainital synclines results from tectonic repeti-tion. Our thickness estimates are based onnumerous, well-correlated sections in the bestoutcrops. Secondly, siliciclastic rocks increase inabundance towards the south-east (Fig. 4). Forexample, near Solan and at Nigalidhar syncline,strata above surface 3 are composed mainly ofcarbonate, with only minor shale and siltstone

found preferentially above flooding surfaces.Within the same stratigraphic interval at Musso-orie syncline, interbedded siltstone and cherty/silty dolomite are comparatively abundant. Simi-larly, at Garhwal syncline, strata above surface 4are composed primarily of interbedded siltstoneand cherty/silty dolomite (except for the upper-most Krol D), with minor fine-grained sandstone.At Nainital syncline, siltstone and cherty/siltydolomite are the main rock types throughout theinterval above surface 4, and fine-grained sand-stone is relatively abundant. We infer that thesource of siliciclastic sediment lay to the south-east. Thirdly, although the overall stratigraphicarchitecture is relatively tabular, the pinch-outtowards the south-east of subtidal facies overlyingsurfaces 4 and 6 may be due to subtle regionalonlap (Figs 4 and 5). All the rocks were disruptedby faulting and folding during the India–Eurasiacollision, beginning � 55 million years ago(Powers et al., 1998; Hodges, 2000; Najman &Garzanti, 2000).

FACIES ASSOCIATIONS

The transect constructed from measured sectionsand local mapping at Solan and at Nigalidhar,

310

790780770

0 20 40 km

NSolan

Nigalidhar

Mussoorie

Kaudiyala

Nainital

Dehradun

Rishikesh

Baliana Group

Krol Group

Tal Group

Main Boundary Thrust

Study area

Delhi

Study areas

Krol syncline

Garhwal syncline

Nigalidhar syncline

Mussoorie syncline

Nainital syncline

(A)

(B)

(C)

(D)(E)

(F)

(G)

Pachmunda syncline

300

300

(Blaini and Infra Krol formations)

Pre-Baliana groups

Fig. 1. Map showing exposures of the Baliana, Krol and Tal groups in Lesser Himalaya fold and thrust belt and studyareas (after Singh & Rai, 1983). Letters (A) to (G) are locations of representative sections shown in Fig. 4.

Neoproterozoic Krol platform of Lesser Himalaya, India 923


Mussoorie, Garhwal and Nainital synclines(Fig. 4) is divided into 18 facies (Table 1). Thesefacies are grouped into eight facies associationson the basis of palaeoenvironmental significance(Fig. 5; Table 2). A generalized reconstruction offacies distribution and platform architecture isprovided in Fig. 6.

Deep subtidal facies association

The deep subtidal facies association includesthree facies: calcareous shale and siltstone, inter-bedded shale and limestone, and muddy dolo-mite (Fig. 7). The muddy dolomite facies ispresent as a 5 to 15 m thick, laterally persistentunit that caps the glacial diamictite of the BlainiFormation and as a < 2 m thick unit that overlies

surface 2 (Fig. 4). Rocks are thinly parallel lam-inated. In the upper part of facies units, muddydolomite laminae are interlaminated with shale(Fig. 8A). The calcareous shale and siltstonefacies constitutes the bulk of the Infra KrolFormation as well as part of the Krol D abovesurface 6 (Fig. 4). The facies is for the most partmonotonously laminated, with locally developedlayers or lenses of 2 to 5 cm thick, fine- to veryfine-grained, cross-laminated sandstone withslightly erosional bases (Fig. 7A). The interbed-ded shale and limestone facies constitutes themain component of Krol A. It forms shale–limestone rhythmites (Fig. 8B) and 2 to 8 m thickunits of alternating shale and limestone (Figs 7Band 8C). The latter include 2 to 10 cm thick,laterally discontinuous beds of cross-laminated

Neopro

tero

zoic

Jaunsar

Gro

up

Sim

la G

roup

BasantpurFormation

KuniharFormation

ChaosaFormation

SanjauliFormation

ChandpurFormation

NagthatFormation

Balia

na G

roup

BlainiFormation

Infra KrolFormation

Kro

l G

roup

Tal G

roup

Cam

bri

a

Mahi Formation

KauriyalaFormation

Jarashi Formation

Deo Ka Tibba Formation

DhaulagiriFormation

term

ina

l Pro

tero

zoic

~590 Ma

~543 Ma

Krol A

Krol B

Krol C

Krol D

Krol E

JarashiFormation

MahiFormation

Argillaceous/Chert Member

Blaini Formation

Cap carbonate

Infr

a K

rol

For

mat

ion

Kau

riyal

a F

orm

atio

n

8

6

7

5

4

3

2

1

E1

E2

SS

AA C

Diamictite Dolomite

Shale/siltstone

Sandstone

Limestone/shale Dolomite and siltstone Karstic breccia

Oolitic grainstone

Calcrete/siltstone

Phosphorite Regional discontinuity Sequence boundary

KrolSandstone

Deo Ka Tibba Formation

Chambaghat Formation

Reported Ediacaran fossils Acanthomorph acritarchs CyanobacteriaAA CE1 E2Small shelly fossilsSS

Fig. 2. Generalized Neoproterozoic stratigraphy, showing stratigraphic interval studied (shaded), stratigraphicnomenclature, reported fossil horizons and regional stratigraphic discontinuities in Infra Krol Formation and KrolGroup. See Jiang et al. (2002) for details of physical stratigraphy. Palaeontological interpretations are as follows:cyanobacteria (C) and acanthomorph acritarchs (AA) from Tiwari & Knoll (1994); Ediacaran fossils in Krol D (E1)from Shanker et al. (1997); Ediacaran fossils in Krol E (E2) from Mathur & Shanker (1989, 1990) and Shanker et al.(1997); and small shelly fossils (SS) from Kumar et al. (1987) and Bhatt (1991).

924 G. Jiang et al.


fine-grained peloidal packstone/grainstone withminor erosional surfaces (Fig. 8D).

InterpretationThe above three facies are interpreted to haveaccumulated on a storm-influenced subtidal rampor open shelf below fairweather wave base(Fig. 6). The presence of occasional beds andlenses of cross-laminated sandstone and grain-stone/packstone and minor erosional surfacesmay be indicative of storm wave activity,although features such as hummocky cross-stra-tification and graded bedding have not beenobserved. The fine-grained sandstone and carbon-ate grainstone are interpreted to have beenderived from proximal, shallow subtidal areas ofthe platform, and transported seaward by storm-

induced currents (Schieber, 1994, 1999), as indi-cated by the upward-coarsening trend recorded inmeasured sections.

Shallow subtidal facies association

The shallow subtidal facies association includestwo mappable facies: dolograinstone/packstone–shale and dolopackstone/wackestone–siltstone(Tables 1 and 2). The first facies is present inthe uppermost part of Krol A and the lowermostpart of Krol C above surface 3, and the second ispresent mainly in the Krol D immediately abovesurfaces 5 and 6 (Figs 4 and 5).

The dolograinstone/packstone–shale faciesmakes up 1 to 6 m thick cycles that contain ashale-rich lower part and a carbonate-rich upper

Kro

l G

roup

Infra KrolFormation

Blaini Formation

Mahi F

orm

ation

JarashiFormation

Kauri

yala

Form

ation

?

Nainital Korgaisyncline

Nigalidhar synclineSolan

Blaini Formation: 1--diamictite, 1a--pink dolomite; Infra Krol Formation: 2--siltstone/shale

with minor sandstone; Krol sandstone: 3--sandstone; Mahi Formation (Krol A): 4--black shale and siltstone,

5--interbedded shale and limestone; 6--interbedded shale with thin limestone; Jarashi Formation (Krol B):

7--red shale/siltstone with dolomite; Kauriyala Formation (Krol C, D, and E): 11--thickly bedded to massive,

siliceous dolomitic limestone/limestone, 12--thickly bedded to massive dolomitic limestone/limestone,

13--interbedded dolomitic limestone and shale, 14--interbedded dolomitic limestone and shale with arenite

bands, 15--interbedded arenite, siltstone with dolomitic limestone/limestone, 16--bedded arenite; 17 (Krol E)--

Argillaceous dolomitic limestone and calcareous shale0 m

500

1000

60 km 4 km 35 km 7 km 45 km 110 km

Rajpur(Mussoorie syncline)

Bandal River(Mussoorie syncline)

Kaudiyala(Garhwal syncline)

11a

2

65

6

4

6567

121612

13

1

131416

13

1216

12

1513

?

6

7

12

17

12

13

12

13

17

1312

13

1213

1213

12

7

6

2

?1

17

13

1213

12

13

1276

5

6

2

6565

6

712

12

1713

12

13

12

13127

6

2345

76

12

2

Fig. 3. Stratigraphic correlation of Infra Krol Formation and Krol Group based on lithological similarity andthickness, and implying a sedimentary basin centred on Mussoorie syncline. Redrawn from Shanker & Mathur(1992).



Garhwal (B)

SoutheastMussoorie (C)

Mussoorie (D)

NorthwestMussoorie (E)

Nigalidhar (F)

Solan (G)

Nainital (A)

Diamictite

Calcareous shaleand siltstone

Muddydolomite

Sandstone/siltstone

Stromatolite-rich dolomite

Sequenceboundary

Regionaldiscontinuity

Karstic breccia

Grainstone/packstone

Interbedded shaleand limestone

Cherty/silty dolomite-siltstone

Microbialdolomite

Minor erosional surfaceLarge-scalecross-stratificationSmall-scalecross-lamination

Fenestral microbial laminae

Parallel Lamination

Ripple marks

Intraclast

Tepee structureDesiccation cracks

Pisolite

BrecciationDomalstromatoliteColumnarstromatoliteElongate columnarstromatoliteMicrobiallaminae

Chert nodules/layers

Phosphorite

OncoidOoidPeloid

Shale clast

Gypsum cast

Organic-richwackestone-shale

Dolopackstone/wackestone-siltstone

Calcrete

Massive sparrydolomite

8

7

6

5

4

3

2

1

Open s

helf ?

Rim

med s

helf

Sili

cic

lastic r

am

pC

arb

onate

ram

p

Fig

. 7

B

Krol sandstone

Blaini Formation

Infra KrolFormation

Krol A

Krol B

Krol C

Krol D

Krol E

Tal Group

Kro

l

Gro

up

010

020

0 m

BSD

GP

WM

BSD

GP

WM

BSD

GP

WM

BSD

GP

WM

BSD

GP

WM BS

DG

PW

M

BSD

GP

WM

BSD

GP

WM

Fig

. 7A

Fig

. 1

0B

B--Breccia D--Dolomite G--Grainstone P--Packstone W--Wackestone M--Lime mudstone S--Shale/siltstone

Fig

. 1

0A

Fig

. 10C

Fig

. 7

C

926 G. Jiang et al.


part (Fig. 7B and C). The shale-rich part iscomposed of greenish to dark grey, calcareousshale, with millimetre-thick lime mudstonelayers or lenses. The carbonate-rich part is com-posed of alternating thin beds of fine-grained,oolitic–peloidal grainstone/packstone and calcar-eous shale (Fig. 9A and B). The grainstone/pack-stone layers are typically < 6 cm thick, laterallydiscontinuous and enclosed in shale (Fig. 9B).Small-scale cross-lamination, minor erosionalsurfaces and minor graded bedding are preservedin the grainstone/packstone layers.

The dolopackstone/wackestone–siltstone faciescomprises 2 to 5 m thick cycles, the lower parts ofwhich are siltstone rich and the upper parts

carbonate rich. In the siltstone-rich parts, silt-stone is grey and calcareous, commonly 5–10 cmthick and unevenly interbedded with 0Æ5 to 8 cmthick layers of fine-grained peloidal packstone/wackestone (Fig. 9C). Small-scale cross-lamin-ation is present in both lithologies. The carbon-ate-rich upper part of each cycle is composedmainly of fine-grained, peloidal and silty pack-stone, with millimetre-thick, calcareous siltstonelayers and lenses (Fig. 9D). Cross-lamination andminor erosional surfaces are common.

InterpretationThese two facies are interpreted to represent ashallow subtidal ramp or open shelf environmentnear fairweather wave base. The shale-rich andsiltstone-rich parts of the two facies contain limemudstone and wackestone layers, respectively,indicating that the fine-grained sediment was notwinnowed away by wave activity. However, thepresence of cross-lamination and erosional surfa-ces suggests a modest level of wave action,

1

2

3

5

6

78

4

50 km200

m

NainitalGarhwalMussoorieNigalidharSolan(A)(B)(C)(D)(E)(F)(G)

1

2

3

4

5

6

7

8

Krol A

Cam

bri

ante

rmin

al P

rote

rozo

ic

Blaini Fm

Infr

a K

rol

Fm

Krol B

Krol C

Krol D

Krol ETa

l Gro

up

Glacial-marine

Deep subtidal

Shallow subtidal Incised-valley fills

Oolitic sand shoal

Peritidal siliciclastic-carbonate

Shelf-lagoon

Peritidal carbonate complex

?

Shale-based cycles Siltstone – silty/cherty dolomite alternations Non-cyclic intervalsStromatolitic cycles

Fig. 5. Interpretation of facies associations based on lithofacies and sedimentary structures summarized in Fig. 4,Table 1 and Table 2. Vertical bars show cyclic and non-cyclic intervals.

Fig. 4. Composite stratigraphic sections of Infra KrolFormation and Krol Group showing main lithofacies,sedimentary structures, regional stratigraphic discon-tinuities and their correlation along Lesser Himalaya.Sections located in Fig. 1.



perhaps storm induced. Hence, they may repre-sent environments below fairweather wave basein which shale and siltstone could accumulatefrom suspension, with carbonate being intro-duced during storms. The carbonate-rich parts

of the two facies consist mainly of grainstone andpackstone, with abundant cross-lamination anderosional surfaces. Grainstones are inferred tohave accumulated in wave-influenced environ-ments above fairweather wave base, and pack-

?

?

2

3

> 60 km >150 km

Peritidal stromatolite-rich carbonate complex

Shelf lagoon


Shelf rim ?

Sea level

Fairweatherwave base

Cherty/silty dolomite-siltstone,Fenestral microbialdolomite,Massive sparry dolomite

Organic-rich wackestone/packstone-shale,Stromatolitic dolomite

Wavy microbial dolomite,Oncoid/intraclastic dolograinstone/rudstone,Stromatolitic dolomite,Fenestral microbial dolomite

Stromatoliticreef/mound ?

Slope-basinalrhythmites, turbidites,and breccias ?

1

Storm W.B.

Fairweatherwave base

Sea level

Oolitic grainstone,Dolograinstone/packstone-shale,Dolopackstone/wackestone-siltstone

Calcreous shale and siltstone,Interbedded shale and limestoneMuddy dolomite

Cherty/silty dolomite-siltstone,Fenestral microbialdolomite,Massive sparry dolomite

2

3

1

Deep subtidal Shallow subtidal


A Rimmed shelf

B Ramp

>250 km

Basinal shale ?

Fig. 6. Palaeoenvironmental reconstruction of geometry and facies distribution for a peritidal rimmed shelf (A) andramp (B) of the Krol platform. Numbered lines show configuration of regional palaeogeographic reconstructions:1 corresponds to profile shown in Fig. 5 (not necessarily perpendicular to depositional strike); 2 and 3 are inter-pretations implied by previous publications (e.g. Singh, 1980a,b; Singh & Rai, 1980).

928 G. Jiang et al.


Table

1.

Su

mm

ary

of

facie

sfr

om

the

Infr

aK

rol

Form

ati

on

an

dth

eK

rol

Gro

up

.

Facie

sC

on

stit

uen

tsB

ed

din

gS

ed

imen

tary

stru

ctu

res

Calc

are

ou

ssh

ale

an

dsi

ltst

on

e(1

)C

alc

are

ou

ssh

ale

an

dsi

ltst

on

e,

rare

very

fin

e-g

rain

ed

san

dst

on

eL

ate

rall

ycon

tin

uou

sbed

s,com

mon

lyas

mon

oto

nou

s,n

on

-cycli

cin

terv

als

Mil

lim

etr

e-t

hic

kp

ara

llel

lam

inati

on

,sm

all

-scale

wavy

cro

ss-l

am

inati

on

insa

nd

ston

ela

yers

Inte

rbed

ded

silt

ston

ean

dsa

nd

ston

e(2

)S

ilts

ton

ean

dvery

fin

e-g

rain

ed

tofi

ne-g

rain

ed

san

dst

on

e3

to20

cm

thic

k,

late

rall

yd

iscon

-ti

nu

ou

ssa

nd

ston

ela

yers

an

dle

nse

s,in

terb

ed

ded

wit

hsi

ltst

on

e

Rip

ple

cro

ss-l

am

inati

on

,p

ara

llel

lam

inati

on

,le

nti

cu

lar

bed

din

g,

flase

rbed

din

gIn

terb

ed

ded

shale

an

dli

mest

on

e(3

)C

alc

are

ou

ssh

ale

/sil

tsto

ne,

lim

em

ud

ston

e/w

ackest

on

e,

rare

fin

e-g

rain

ed

pelo

idal

packst

on

e/g

rain

ston

e

Alt

ern

ati

on

sof

late

rall

ycon

tin

uou

ssh

ale

an

dli

mest

on

e,

rare

len

ticu

lar,

2to

10

cm

thic

kp

ackst

on

e/g

rain

ston

ela

yers

Mil

lim

etr

e-t

hic

kp

ara

llel

lam

inati

on

,ra

rew

avy

cro

ss-l

am

inati

on

an

dm

inor

ero

sion

al

surf

aces

inp

ackst

on

e/

gra

inst

on

ela

yers

an

dle

nse

sM

ud

dy

dolo

mit

e(4

)M

ud

dy

dolo

mit

e,

locall

yin

terb

ed

ded

wit

hm

illi

metr

e-s

cale

fiss

ile

shale

Late

rall

ycon

tin

uou

s,th

inly

bed

ded

(1–5

mm

),p

ara

llel

lam

inae

Para

llel

lam

inati

on

Dolo

gra

inst

on

e/

packst

on

e–sh

ale

(5)

Fin

e-g

rain

ed

ooli

tic–p

elo

idal

dolo

gra

inst

on

e/p

ackst

on

e,

calc

are

ou

ssh

ale

,ra

rein

tracla

stic

gra

inst

on

e/p

ackst

on

e

1to

4cm

thic

k,

late

rall

yd

iscon

tin

uou

sd

olo

gra

inst

on

e/p

ackst

on

ela

yers

an

dle

nse

s,in

terb

ed

ded

wit

hla

tera

lly

con

tin

uou

ssh

ale

layers

Gra

inst

on

e/p

ackst

on

e:

min

or

ero

sion

al

surf

aces

again

stsh

ale

,sm

all

-scale

cro

ss-l

am

inati

on

,ra

ren

orm

al

gra

din

g.

Sh

ale

:p

ara

llel

lam

inati

on

Dolo

packst

on

e/

wackest

on

e–si

ltst

on

e(6

)

Fin

e-g

rain

ed

pelo

idal,

silt

yd

olo

packst

on

e/w

ackest

on

e,

calc

are

ou

ssi

ltst

on

e

Inte

rbed

ded

un

its,

late

rall

ycon

tin

uou

sbed

din

gW

ave

rip

ple

san

dsm

all

-scale

cro

ss-l

am

inati

on

inboth

silt

ston

ean

dd

olo

gra

inst

on

e/p

ackst

on

eO

oli

tic

gra

inst

on

e(7

)F

ine-

tocoars

e-g

rain

ed

,w

ell

-sort

ed

,ooli

tic

gra

inst

on

e,

wavy

mic

robia

lla

min

ae

an

dra

rein

tracla

stic

gra

inst

on

e

Tabu

lar

tole

nti

cu

lar,

5to

50

cm

thic

kbed

s,fa

int

1–5

cm

lam

inae

Abu

nd

an

tta

bu

lar–

pla

nar

cro

ss-b

ed

din

g,

trou

gh

cro

ss-b

ed

din

gan

dsm

all

-scale

cro

ss-l

am

inati

on

Wavy

mic

robia

ld

olo

mit

e(8

)M

icro

bia

lla

min

ae,

mic

riti

cla

min

ae

an

dgra

inst

on

ela

min

ae,

pelo

ids,

ooid

s,in

tracla

sts

Th

inly

(mil

lim

etr

e-t

hic

k)

inte

rbed

ded

un

its,

un

du

lati

ng

surf

aces,

intr

acla

sts

pre

serv

ed

insm

all

rip

ple

sor

as

fill

betw

een

stro

mato

lite

head

s

Late

rall

yli

nked

,lo

w-r

eli

ef

(2–10

cm

)st

rom

ato

lite

s,in

situ

bro

ken

intr

acla

sts

aro

un

dst

rom

ato

lite

s,w

ave

rip

ple

san

dcro

ss-l

am

inati

on

On

coid

/in

tracla

stic

dolo

gra

inst

on

e/

rud

ston

e(9

)

Intr

acla

sts

(0Æ5

–2

cm

,u

pto

5cm

)an

don

coid

s(1

–10

cm

);m

atr

ixof

lim

em

ud

ston

ean

dfi

ne-g

rain

ed

pelo

ids,

ooid

san

din

tracla

sts

Tabu

lar

tole

nti

cu

lar,

dis

con

tin

uou

sbed

s,la

tera

lly

traceable

tom

icro

bia

l,st

rom

ato

liti

cd

olo

mit

es

an

dth

inooli

tic

gra

inst

on

ela

yers

Norm

al

gra

din

gexp

ress

ed

by

intr

acla

sts,

cro

ss-l

am

inati

on

an

dri

pp

les

Str

om

ato

liti

cd

olo

mit

e(1

0)

Cou

ple

tsof

sparr

yd

olo

mit

ean

dcri

nkle

dm

icro

bia

lla

min

ae,

len

ticu

lar

bed

sof

lim

em

ud

ston

e,

pelo

ids,

intr

acla

sts,

on

coid

san

dooid

sbetw

een

stro

mato

lite

head

s

Con

vex

tou

nd

ula

tory

lam

inae,

mil

lim

etr

e-

tocen

tim

etr

e-t

hic

k,

late

rall

yd

iscon

tin

uou

scla

stic

layers

;u

nit

su

pto

30

mth

ick

Larg

ed

om

al

an

dcolu

mn

ar

stro

mato

lite

sof

10–120

cm

syn

op

tic

reli

ef,

inte

rfin

gere

dor

ass

ocia

ted

wit

hlo

w-r

eli

ef

(3–8

cm

)st

rom

ato

lite

san

dgra

din

gu

pw

ard

sin

tofe

nest

ral

mic

robia

ld

olo

mit

eF

en

est

ral

mic

robia

ld

olo

mit

e(1

1)

Dark

,re

lati

vely

org

an

ic-r

ich

lam

inae

inte

rbed

ded

wit

hli

gh

t-colo

ure

d,

irre

gu

lar,

dis

rup

ted

bed

sof

fen

est

ral

fabri

c,

or

thic

km

icro

bia

ld

olo

mit

ela

yers

dis

rup

ted

by

small

,d

iscon

tin

uou

sly

bed

ded

,sp

ar-

fill

ed

fen

est

rae

Irre

gu

lar

bed

sw

ith

thin

(1–3

mm

)la

min

ati

on

,la

tera

lly

dis

con

tin

uou

sL

ow

-reli

ef

(<10

cm

)d

om

al

stro

mato

lite

s,fe

nest

ral

stru

ctu

res,

vu

gs,

tep

ee

stru

ctu

res,

desi

ccati

on

cra

cks

an

dbre

ccia

tion



Table

1.

Con

tin

ued

.

Facie

sC

on

stit

uen

tsB

ed

din

gS

ed

imen

tary

stru

ctu

res

Org

an

ic-r

ich

wackest

on

e/

packst

on

e–sh

ale

(12)

Bla

ck

tod

ark

gre

y,

org

an

ic-r

ich

wackest

on

e/p

ackst

on

ean

dsh

ale

,ra

regra

inst

on

ebed

s,fi

ne-g

rain

ed

pelo

ids,

ooid

s

Alt

ern

ati

on

sof

late

rall

ycon

tin

uou

ssh

ale

–w

ackest

on

e/p

ackst

on

ew

ith

len

ticu

lar,

1to

4cm

thic

kgra

inst

on

ebed

s

Rare

colu

mn

ar

stro

mato

lite

sw

ith

narr

ow

colu

mn

sbu

th

igh

-reli

ef,

para

llel

lam

inati

on

Ch

ert

y/s

ilty

dolo

mit

e–si

ltst

on

e(1

3)

Un

iform

lyor

part

iall

ych

ert

ified

,th

ick

(up

to10

m)

or

thin

(2–15

cm

)d

olo

mit

ela

yers

,in

terb

ed

ded

wit

hd

olo

mit

icsi

ltst

on

e;

5–15%

terr

igen

ou

squ

art

zsi

ltor

san

dgra

ins

ind

olo

mit

e

Alt

ern

ati

on

of

silt

ston

ean

dd

olo

mit

ebed

s,d

iscon

tin

uou

sly

lam

inate

dch

ert

len

ses/

nod

ule

salo

ng

bed

din

gp

lan

es

ind

olo

mit

es

Cen

tim

etr

e-s

ized

dom

al/

colu

mn

ar

stro

mato

lite

sp

art

lyre

pla

ced

by

ch

ert

,w

ave

rip

ple

s,fe

nest

rae,

pis

oli

tes,

desi

ccati

on

cra

cks,

dis

solu

tion

cavit

ies

an

dbre

ccia

tion

Mass

ive

sparr

yd

olo

mit

e(1

4)

Lig

ht-

colo

ure

d,

coars

esp

arr

yd

olo

mit

es,

mic

robia

lla

min

ae

an

dbre

ccia

s;u

pto

10%

well

-sort

ed

qu

art

zsi

ltan

dsa

nd

gra

ins

Mass

ive,

thic

k(>

5m

,u

pto

100

m)

un

its,

fain

t1

to10

cm

thic

kla

min

ae

Cen

tim

etr

e-s

ized

(5–10

cm

reli

ef)

dom

al

stro

mato

lite

s,le

ssre

cry

stall

ized

inte

rvals

con

tain

abu

nd

an

tfe

nest

rae,

pis

oli

tes,

vad

ose

cem

en

ts,

vu

gs,

bre

ccia

tion

an

dzebra

stru

ctu

reM

icro

bia

ld

olo

mit

e(1

5)

Rela

tively

thic

km

icro

bia

ld

olo

mit

ela

yers

dis

rup

ted

by

irre

gu

lar,

spar-

fill

ed

fen

est

rae,

rare

pelo

ids

an

dooid

s

Mass

ive

toir

regu

larl

ybed

ded

,la

tera

lly

dis

con

tin

uou

sla

min

ati

on

Low

-reli

ef

dom

al

an

dcolu

mn

ar

stro

mato

lite

s,ch

ert

len

ses,

fen

est

rae,

vu

gs,

dis

solu

tion

cavit

ies,

tep

ees,

desi

ccati

on

cra

cks

an

dbre

ccia

tion

Sil

icic

last

icsa

nd

ston

e/

silt

ston

e(1

6)

Coars

e-

tofi

ne-g

rain

ed

san

dst

on

es

an

dsi

ltst

on

e,

min

or

con

glo

mera

tes

an

dp

ebbly

san

dst

on

e

Late

rall

yd

iscon

tin

uou

su

nit

sof

vary

ing

thic

kn

ess

.C

on

glo

mera

tes

an

dp

ebbly

san

dst

on

eare

most

lyas

len

ses

alo

ng

the

ero

sion

al

surf

aces

5to

25

mth

ick,

fin

ing-u

pw

ard

un

its,

abu

nd

an

ttr

ou

gh

,ta

bu

lar–

pla

nar

cro

ss-b

ed

din

gan

dsm

all

-scale

cro

ss-l

am

inati

on

,cu

rren

tri

pp

les

Kars

tic

bre

ccia

(17)

Mon

om

ict

or

poly

mic

tw

ith

lith

olo

gy

sim

ilar

toh

ost

rocks

as

well

as

silt

ston

e,

shale

an

dch

ert

cla

sts,

poorl

yso

rted

or

un

sort

ed

,su

ban

gu

lar

toan

gu

lar

cla

sts

of

vary

ing

sizes

from

<1

cm

to3

m;

san

dy,

silt

yan

dm

icri

tic

matr

ix

Th

in(<

0Æ5

m)

or

thic

k(>

2m

,u

pto

30

m),

mass

ive

or

poorl

yd

iffe

ren

tiate

dle

nse

sor

layers

of

vary

ing

thic

kn

ess

,la

tera

lly

traceable

tocalc

rete

Ass

ocia

ted

wit

hfe

nest

rae,

pis

oli

tes,

vad

ose

cem

en

ts,

dis

solu

tion

cavit

ies

an

dvu

gs,

map

pable

kars

tic

lan

dfo

rms

(dep

ress

ion

san

dkars

tic

hig

hs)

;bre

ccia

-an

dsa

nd

ston

e/s

ilts

ton

e-fi

lled

dykes

an

dd

isso

luti

on

cavit

ies

exte

nd

ing

dow

nw

ard

sin

tou

nd

erl

yin

gro

cks

from

2m

to50

mC

alc

rete

(18)

Bu

ff-c

olo

ure

d,

mass

ive

tofa

intl

yla

min

ate

dla

yers

or

len

ses

of

dolo

mu

dst

on

e,

lim

em

ud

ston

ein

silt

ston

e,

part

lysi

licifi

ed

patc

hes,

pis

oli

tele

nse

s,re

lict

cla

sts,

ch

ert

rubble

san

dkars

tic

bre

ccia

s

Late

rall

yd

iscon

tin

uou

sover

metr

es

tote

ns

of

metr

es

Clo

tted

mic

riti

can

dfl

oati

ng

textu

res,

ass

ocia

ted

wit

hkars

tic

bre

ccia

s,d

isso

luti

on

cavit

ies

an

dvu

gs

930 G. Jiang et al.


Table

2.

Su

mm

ary

of

facie

sass

ocia

tion

sof

the

Infr

aK

rol

Form

ati

on

an

dth

eK

rol

Gro

up

.

Facie

sass

ocia

tion

sF

acie

sS

trati

gra

ph

icu

nit

sL

ate

ral

tren

ds

Vert

ical

tren

ds

En

vir

on

men

tal

inte

rpre

tati

on

Deep

subti

dal

[1]

Calc

are

ou

ssh

ale

an

dsi

ltst

on

e(1

)In

terb

ed

ded

shale

an

dli

mest

on

e(3

)M

ud

dy

dolo

mit

e(4

)

Most

of

the

Infr

aK

rol

Fm

an

dK

rol

A;

up

per

Kro

lD

above

surf

ace

6

Tabu

lar

un

its;

late

rall

ycon

tin

uou

sF

acie

s1

gra

des

up

ward

sto

Facie

s2;

Facie

s3

gra

des

up

ward

sto

Facie

s5

or

6

Facie

s1:

subti

dal

sili

cic

last

icra

mp

or

op

en

shelf

Facie

s3:

subti

dal

carb

on

ate

ram

pS

hall

ow

subti

dal

[2]

Dolo

gra

inst

on

e/p

ackst

on

e–

shale

(5)

Dolo

packst

on

e/

wackest

on

e–si

ltst

on

e(6

)

Up

per

Kro

lA

;lo

wer

Kro

lC

;K

rol

Dan

dK

rol

E

Tabu

lar;

late

rall

ycon

tin

uou

sF

acie

sarr

an

ged

in0Æ5

to5

mth

ick,

shale

/si

ltst

on

e-b

ase

dcycle

s;gra

de

up

ward

sto

Facie

s10,

12,

13,

14

an

d15

Su

bti

dal,

mix

ed

sili

cic

last

ican

dcarb

on

ate

ram

por

op

en

shelf

San

dsh

oal

[3]

Ooli

tic

gra

inst

on

e(7

)L

ow

er

Kro

lC

Tabu

lar

or

len

ticu

lar;

gra

des

toF

acie

s9,

10,

12

Gra

des

up

ward

toF

acie

s9,

10

an

d12

San

dsh

oal

on

ara

mp

or

op

en

shelf

Peri

tid

al

carb

on

ate

com

ple

x[4

]W

avy

mic

robia

ld

olo

mit

e(8

)O

ncoid

/in

tracla

stic

Dolo

gra

inst

on

e/

rud

ston

e(9

)S

trom

ato

liti

cd

olo

mit

e(1

0)

Fen

est

ral

mic

robia

ld

olo

mit

e(1

1)

Up

per

Kro

lC

;lo

wer

Kro

lD

Facie

s8

gra

des

toF

acie

s9

an

d10;

Facie

s10

gra

des

toF

acie

s11;

Ass

ocia

tion

[4]

gra

des

toA

ssocia

tion

[5]

an

d[6

]so

uth

-east

ward

Str

om

ato

lite

size

an

dsy

nop

tic

reli

ef

decre

ase

up

ward

s;fa

cie

sarr

an

ged

in1

to10

mth

ick,

stro

mato

liti

ccycle

s;F

acie

s8

an

d9

toF

acie

s10

toF

acie

s11;

Ass

ocia

tion

[4]

gra

des

up

ward

sto

Ass

ocia

tion

[5]

an

d[6

]

Tid

al

flat–

barr

ier

com

ple

xin

ari

mm

ed

shelf

;fa

cie

sfo

rma

mosa

icp

att

ern

,re

pre

sen

tin

gcon

cu

rren

tsh

all

ow

subti

dal,

inte

rtid

al

an

dsu

pra

tid

al

en

vir

on

men

tson

the

flats

Lagoon

al

[5]

Org

an

ic-r

ich

wackest

on

e/

packst

on

e–sh

ale

(12)

Str

om

ato

liti

cd

olo

mit

e(1

0)

Up

per

Kro

lC

;lo

wer

Kro

lD

Facie

s12:

tabu

lar,

late

rall

ycon

tin

uou

sbod

ies

Facie

s10:

len

ticu

lar

un

its

Facie

sarr

an

ged

to0Æ5

to5

mth

ick,

shale

-base

dcycle

s;F

acie

s12

toF

acie

s10;

Ass

ocia

tion

[5]

gra

des

up

ward

sto

Ass

ocia

tion

[6]

Su

bti

dal

toin

tert

idal

back

barr

ier,

shelf

lagoon

ina

rim

med

carb

on

ate

shelf

Peri

tid

al

sili

cic

last

ic–

carb

on

ate

[6]

Inte

rbed

ded

silt

ston

ean

dsa

nd

ston

e(2

)C

hert

y/s

ilty

dolo

mit

e–

silt

ston

e(1

3)

Mass

ive

sparr

yd

olo

mit

e(1

4)

Mic

robia

ld

olo

mit

e(1

5)

Mid

dle

Infr

aK

rol

Fm

;K

rol

B;

low

er

an

du

pp

er

Kro

lC

;u

pp

er

Kro

lD

an

dK

rol

E

Tabu

lar

tole

nti

cu

lar

un

its;

sili

cic

last

iccom

pon

en

tsd

ecre

ase

ton

ort

h-w

est

Facie

sarr

an

ged

inu

nit

sof

silt

ston

e–si

lty/c

hert

yd

olo

mit

ealt

ern

ati

on

,or

non

-cycli

cin

terv

als

of

overa

llu

pw

ard

-in

cre

asi

ng

exp

osu

re-

rela

ted

featu

res

Pro

xim

al

tid

al

flat

en

vir

on

men

tsin

sili

cic

last

ic–carb

on

ate

ram

pan

dri

mm

ed

carb

on

ate

shelf

Incis

ed

vall

ey

fill

[7]

Sil

icic

last

icsa

nd

ston

e/

silt

ston

e(1

6)

Mid

dle

Infr

aK

rol

Fm

;lo

wer

Kro

lC

Gra

des

late

rall

yto

Facie

s2,

15

an

d17

Gra

des

up

ward

sto

Facie

s1

an

d12

Incis

ed

vall

ey

fill

insi

licic

last

icra

mp

an

dcarb

on

ate

shelf

Kars

tic

fill

[8]

Kars

tic

bre

ccia

(17)

Calc

rete

(18)

Main

lyalo

ng

surf

ace

4an

d5;

thin

bre

ccia

len

san

dla

yers

ass

ocia

ted

wit

hA

ssocia

tion

[6]

Late

rall

yvari

able

len

ses

an

dla

yers

;d

ecre

asi

ng

thic

kn

ess

ton

ort

h-w

est

Gra

des

up

ward

sto

Ass

ocia

tion

[2]

an

d[3

]

Pala

eokars

tic

pro

du

cts

fill

ed

inkars

tic

dep

ress

ion

s,an

dd

ykes;

subaeri

al

pre

cip

itati

on



stones may have deposited below fairweatherwave base. The close association of grainstoneand packstone (Fig. 7B) indicates that environ-ments were not far from the fairweather wavebase, different from the deep subtidal faciesassociation described above. Carbonate particlesmay have been derived from local shoals or bars(Fig. 6B). The alternation of shale/siltstone-richand carbonate-rich hemi-cycles suggests system-atic variations in palaeowater depth and fluctua-tions in the supply of terrigenous clastic sediment(cf. Holland & Patzkowsky, 1998).

Sand shoal association

The sand shoal facies association consists of fine-to coarse-grained oolitic grainstone with subordi-nate wavy microbial laminae and rare intraclasticbeds and lenses (Tables 1 and 2). We separate thisfacies association from relatively thin ooliticgrainstone layers in other facies associationsbecause it forms an interval as much as 50 mthick in the lower part of Krol C above surface 4(Figs 4 and 5). Grainstone beds are typically5–50 cm thick, separated by thin (< 5 cm) faint

lm w p g ds

B

shal

e-ba

sed

cycl

es

C

lm w p g ds

40

30

20

10

0 m

40

30

20

10

0 m

shal

e-ba

sed

cycl

es

Kro

l AK

rol B

vf f m c v

40

30

20

10

0 m

A

s

Infr

a K

rol F

orm

atio

n

Kro

l CK

rol B

Green/gray shale/siltstone SandstoneReddish siltstone Lime mudstone Wackestone Packstone/grainstone

Cherty/silty dolomite Microbial dolomite Parallel lamination Cross-lamination Minor erosional surface

Lenticular bedding

Flaser bedding

Ripple marks Desiccation cracks Gypsum cast Microbial laminae Fenestral structures

s: shale/siltstone, vf: very fine-grained, f: fine-grained, m: medium-grained, c: coarse-grained, vc: very coarse-grained; lm: lime mudstone, w: wackestone, p: packstone, g: grainstone, d: dolomite

Deep subtidal PeritidalShallow subtidal Shallow subtidal-deep subtidal Shallowing-upward trend Deepening-upward trend

Fig. 7. Representative stratigraphic sections of deep subtidal, shallow subtidal and peritidal facies associations. (A)Deep subtidal calcareous shale/siltstone facies to peritidal interbedded sandstone and siltstone facies of middle InfraKrol Formation. Partial measured section at Deoghat, near Solan. (B) Deep subtidal interbedded shale and limestonefacies to shallow subtidal dolograinstone/packstone–shale facies (Krol A), to peritidal cherty/silty dolomite–siltstonefacies (Krol B). Partial measured section along south limb of Nainital syncline, north of Runsi village. (C) Peritidalcherty/silty dolomite–siltstone (Krol B) to transitional deep to shallow subtidal dolograinstone/packstone–shalefacies, to peritidal microbial dolomite facies (Krol C). Partial measured section at Kaudiyala, north limb of Garhwalsyncline. See Fig. 4 for stratigraphic location.

932 G. Jiang et al.


microbial laminae and intraclastic beds andlenses (Fig. 9E). Decimetre-scale tabular andtrough cross-stratification characterizes mostoolitic beds, although they are locally cryptic.Ooids display considerable size variationbetween beds, but grains within an individualbed are commonly well sorted. Ooids are typic-ally 0Æ3–1Æ5 mm in diameter, but as large as2Æ5 mm in trough cross-stratified sets. Gradingand poor sorting are observed locally in the latter.Most ooids have cores composed of one or morequartz silt grains. In the case of some large ooids,cores are microbial or composed of micriticintraclasts. Concentric coatings of individualooids range in thickness from < 0Æ01 to 0Æ05 mm.Ooid shape ranges from nearly spherical toelongate (2:1 ratio of apparent long and shortdimensions) to irregular (Fig. 9F).

InterpretationThe thick grainstone interval in Krol C is inter-preted as a subtidal carbonate sand shoal subjec-ted to sustained high-energy conditions. The

abundance of quartz silt grains as ooid nucleiindicates a ready source of siliciclastic particles ata newly submerged ramp or open shelf developedon a karstic surface. The interlayering of grain-stone with faint, wavy microbial laminae suggestsspatial and temporal variations in the intensityand frequency of wave action (Sweet & Knoll,1989). The presence of trough cross-stratificationsuggests migration of current-generated bedformsin a broad, shallow subtidal environment.

Peritidal carbonate complex

The peritidal carbonate complex includes fourlithofacies: wavy microbial dolomite, oncoidand intraclastic dolograinstone/rudstone, stro-matolitic dolomite and fenestral microbial dolo-mite (Tables 1 and 2). These facies togetherform thick, stromatolite-rich carbonate units inthe Krol C and Krol D at Mussoorie andNigalidhar synclines and at Solan (Figs 4 and5). Facies are commonly arranged into 2 to 12 mthick cycles that begin with wavy microbial

Fig. 8. Deep subtidal facies association. (A) Muddy dolomite facies capping glacial diamictites of Blaini Formation,showing thinly interbedded muddy dolomite laminae and fissile shale laminae. From Dhanaulti, Mussoorie syncline.(B) Thinly laminated shale–limestone rhythmites of middle Krol A, Nainital syncline. (C) Interbedded shale andlimestone facies expressed as cycles with alternating shale-rich part and limestone-rich part, upper Krol A, Solan. (D)Small-scale cross-lamination in fine-grained peloidal grainstone (detail of limestone in C). Scales: A (metre), 15 cm; B(hammer), 32 cm; C (field assistant), 1Æ7 m high; and D (coin), 1Æ8 cm in diameter.



dolomite, pass upwards into domal and colum-nar stromatolites and are capped with fenestralmicrobial dolomite (Fig. 10A). Oncoid andintraclastic dolograinstone/rudstone is presentthroughout each cycle, but is generally moreabundant at the base and in the lows betweenstromatolite heads. Large stromatolites in placespass laterally into smaller stromatolites, ooid/

peloid-rich microbial dolomite or, less com-monly, into intraclastic rudstone. As a conse-quence, the facies forms a mosaic of microbiallaminae and stromatolite-rich carbonate ratherthan a series of stacked sheets. Individual cyclesand their component facies cannot be tracedlaterally more than a few tens to hundred ofmetres.

Fig. 9. Facies of shallow subtidal and sand shoal facies associations. (A) Interbedded calcareous shale and fine-grained, oolitic–peloidal grainstone/packstone, lower part of Krol C, Kaudiyala section, Garhwal syncline. (B)Lenticular peloidal grainstone interbedded with laminated calcareous shale, lower part of Krol C, Kaudiyala section,Garhwal syncline. (C) Cross-laminated, fine-grained peloidal packstone interbedded with calcareous siltstone, basalpart of Krol D above surface 5, south cliff of Krol Hill, Solan. (D) Cross-laminated, fine-grained, peloidal and siltypackstone and calcareous siltstone. Siltstone layers are chertified and expressed by positive relief on weatheredsurface. Basal part of Krol D above surface 5, south cliff of Krol Hill, Solan. (E) Oolitic grainstone with faint microbiallaminae, Krol C above surface 4, Nigalidhar syncline. (F) Oolitic grainstone from (E). Scales: A and E (pencil),14Æ5 cm; B (coin), 1Æ8 cm in diameter; C (coin), 2 cm in diameter; D (hammer), 32 cm.

934 G. Jiang et al.


Wavy microbial dolomite is composed of 1to 10 cm thick beds of grey microbial laminae(1–10 mm thick) and dark micritic laminae(0Æ5–2 mm thick), interstratified with 2 to 5 cmthick beds of fine-grained oolitic/peloidal/intra-clastic dolograinstone. Some microbial laminaecontain fine-grained peloids, 0Æ1–0Æ3 mm in diam-eter. Dolograinstone layers contain abundant

cross-lamination and erosional surfaces (Fig. 11Aand B). Ooids are 0Æ2–0Æ8 mm in diameter, withsilt or micrite grains in the centre and concentric,intercalated organic-rich and inorganic coatings.Peloids are micritic grains 0Æ1–0Æ3 mm in diam-eter. Intraclasts are angular to subangular parti-cles 0Æ5–3 mm in diameter, and are commonlypresent as a minor component in dolograinstone.

lm w p g ds

40

30

20

10

0 m

50

Patc

h r

eef ?

Patc

h r

eef ?

Kro

l C

shal

e-ba

sed

cycl

es

Kro

l C

Kro

l C

Domal stromatolites Columnar stromatolites Elongate columnar stromatolites

Wavy microbial laminae

Ooids Peloids Oncoids Intraclasts Pisolites

Brecciaion

lm w p g ds

40

30

20

10

0 m

50

silts

tone

-silt

y/ch

erty

dol

omite

alte

rnat

ions

A

stro

mato

litic

cyc

les

shale

-base

d c

ycle

s

B C

lm w p g ds

40

30

20

10

0 m

50

Organic-rich wackestone

Microbial laminae

s: shale/siltstone, lime mudstone, w: wackestone, p: packstone, g: grainstone, d: dolomite

Organic-rich shale Siltstone Packstone Grainstone Cherty/silty dolomite

Microbial dolomite Fenestral microbial laminae

Sand shoal Peritidal siliciclastic-carbonatePeritidal complex Shelf lagoon Shallowing-upward trend

Desiccation cracks

Fig. 10. Representative stratigraphic sections of peritidal complex, lagoonal and peritidal carbonate–siliciclasticfacies associations. (A) Carbonate sand shoal to peritidal stromatolite-rich facies, Krol C above surface 4; partialmeasured section along south cliff of Krol Hill, Solan. (B) Organic-rich wackestone/packstone–shale and stromat-olite-rich facies of lagoonal setting, Krol C above surface 4, Nigalidhar syncline. (C) Organic-rich wackestone/packstone–shale and stromatolitic dolomite facies of lagoonal setting to peritidal cherty/silty dolomite–siltstonefacies, Krol C above surface 4, Nainital syncline. See Fig. 4 for stratigraphic location.



Low-relief (2–10 cm) laterally linked stromato-lites are present in some intervals, with intra-clasts forming lenses between stromatolite heads.

Stromatolitic dolomite contains abundant stro-matolites of varying shapes and sizes. Largedomal stromatolites (Fig. 11C) are typically

unlinked bioherms with up to 120 cm synopticrelief, grading laterally into low-relief domalstromatolites or wavy microbial dolomite. Colum-nar stromatolites are commonly linked, withooids, peloids, oncoids and intraclasts presentin lows between stromatolite heads (Fig. 11D).

C D

E F

A B

Fig. 11. Facies of peritidal carbonate complex. (A) Wavy microbial dolomite, composed of dark grey microbiallaminae and light-coloured, fine-grained peloidal grainstone laminae. Erosional surfaces below grainstone layers,Krol C above surface 4, Nigalidhar syncline. (B) Thinly interbedded microbial and micritic laminae (light colour) andintraclastic grainstone layers, with erosional surfaces below grainstone layers, Krol C above surface 4, Nigalidharsyncline. (C) Large domal stromatolite bioherm, Krol C above surface 4, Solan. (D) Columnar stromatolite withpeloids, ooids, intraclasts and oncoids in troughs between stromatolite heads, Krol C above surface 4, Solan. (E)Fenestral microbial dolomite composed of micritic microbial laminae and discontinuous fenestral fabric (light col-our), Krol C above surface 4, Solan. (F) Plan view of oncoid/intraclastic grainstone consisting of large, concentriconcoids in a fine-grained grainstone matrix, Krol C above surface 4, Solan. Scales: A and E (pencil), 14Æ5 cm; B (pen),12 cm; C and F (hammer), 32 cm; and D (coin), 2 cm in diameter.

936 G. Jiang et al.


Carbonate mud content is very low. Withinparticular cycles, large, isolated domes coalesceupwards into linked or unlinked columns withincreased branching, decreased diameter anddecreased synoptic relief (Fig. 10A).

Fenestral microbial dolomite consists of thinlylaminated, dark grey, relatively organic-richlayers interbedded with light-coloured, irregular,disrupted laminae with fenestral fabric (Fig. 11E),or consists of thick layers disrupted by discon-tinuously bedded, spar-filled fenestrae. Microbiallaminae form metre-thick units that commonlycap stromatolitic cycles (Fig. 10A). Vugs, desic-cation cracks, tepee structures, pisolites andkarstic breccia occur in this facies.

Oncoid and intraclastic dolograinstone/rud-stone forms lenticular beds, commonly associatedwith microbial and stromatolitic dolomite andoolitic grainstone. Oncoids are 1–10 cm in diam-eter, with nuclei of fragments of underlying strataand microbial, organic-rich coatings (Fig. 11F).Intraclasts are typically angular to subangular,varying in size from 0Æ5 mm to 5 cm and arecemented by coarse spar. Normal grading andnearly in situ clasts of stromatolites are found introughs between stromatolite heads.

InterpretationWavy microbial dolomite is interpreted to haveaccumulated in a moderate- to high-energy shal-low subtidal to lower intertidal environment.This is indicated by the presence of low-reliefstromatolites, abundant cross-lamination andgrainstone with allochems such as peloids, ooidsand intraclasts. Microbial laminae containingfine-grained peloids are interpreted to havedeveloped by a combination of cement precipita-tion and binding of particles by microbial mats(Burne & Moore, 1987; Feldmann & McKenzie,1998). Grainstone/packstone layers and lenses areinterpreted to have formed in a storm-influencedsetting, in which ooids and oncoids were trans-ported from adjacent shoals, and intraclasts werereworked from a lithified or partially lithified seafloor. The repeated evolution of stromatolitesfrom large, isolated domes to linked or unlinkedcolumns with increased branching, decreaseddiameter and decreased synoptic relief (Fig. 10A)is interpreted to represent a transition from arelatively undisturbed, subtidal environment toan environment influenced by waves (cf. South-gate, 1989; Sami & James, 1993). The presence offenestral microbial laminae in the upper stroma-tolitic layers indicates stromatolite growth attimes into low-energy, intertidal to supratidal

environments (e.g. Southgate, 1989). Fenestralmicrobial laminae are thought to have formedthrough the binding of micrite by microbial mats,and to have been preserved as a result of earlyfilling by cement or micrite lithification (cf.Shinn, 1986; Sami & James, 1994). The presenceof desiccation cracks, tepee structures, pisolitesand karstic breccia is indicative of upper inter-tidal to supratidal environments (Pratt et al.,1992). Associated oncoids and intraclasts areinterpreted to have formed by storm wave erosionand reworking of stromatolites, microbial lami-nites and relicts of oncoids in shallow-waterenvironments. The generation and transportationof these grains may have resulted from thecombination of storm and fairweather currentsbecause stromatolite intraclasts would have beenderived with difficulty under fairweather condi-tions, given the sparry cements that may repre-sent early sea-floor cementation (cf. Sami & James,1994).

The peritidal complex grades towards thesouth-east into lagoonal facies (Figs 5 and 6). Itmay have acted as a marginal barrier separatingthe shelf lagoon from the open ocean. Comparableexamples have been documented from threePalaeoproterozoic deposits, the Pethei Group ofnorth-west Canada (Sami & James, 1994), theTransvaal Supergroup of southern Africa (Beukes,1987) and the Rocknest platform in north-westCanada (Grotzinger, 1986a,b, 1989b).

Lagoonal facies association

The lagoonal facies association includes twomain facies: organic-rich wackestone/packstone–shale and stromatolitic dolomite (Tables 1 and 2).The facies are present in the Krol C above surface4 and in Krol D above surface 5. Regionally, thefacies association is thickest at Nigalidhar andMussoorie synclines, and comparatively thin atGarhwal and Nainital synclines. It interfingerswith the peritidal carbonate complex describedabove (Fig. 5).

The two facies are commonly arranged as 0Æ5 to5 m thick shale-based cycles or 5 to 10 m thickstromatolitic cycles (Fig. 10B and C). Shale-basedcycles are composed of organic-rich shale andwackestone overlain by oolitic/peloidal pack-stone and stromatolitic dolomite (Fig. 12A). Thestromatolitic facies is similar to that described inthe peritidal complex, but the stromatolites arecharacterized by narrower columns, greater syn-optic relief, locally elongated heads and higherlime mudstone content (Fig. 12B and C). Some



large domes are laterally linked or form isolatedbiostromes up to 120 cm high and 50–200 cm indiameter (Fig. 12D). These large biostromes gradeupwards into smaller columnar stromatolites andfenestral microbial dolomite. Muddy drapes withpeloids, ooids and intraclasts are common in thetroughs between high-relief stromatolite heads(Fig. 10B).

InterpretationThese two facies are interpreted to have beendeposited in a back-barrier shelf lagoon environ-ment with stromatolite patch reefs inboard of theperitidal carbonate complex (Fig. 6A). The lack ofevidence for wave agitation in the organic-richwackestone/packstone–shale facies suggestsdeposition in a low-energy environment. Ooidsand peloids in this facies may have been trans-ported by storm waves from the distal peritidalcomplex, proximal subtidal shoals or patch reefsin the lagoon. Abundant mud drapes betweenstromatolite heads and the higher synoptic reliefof stromatolites indicate that stromatolites had

enough space to grow in this quiet-water setting(cf. Pelechaty et al., 1996). However, the presenceof coarse carbonate particles and the elongation ofsome stromatolite heads parallel to depositionaldip direction suggests that the environment mayhave become disturbed during storm or tidalevents (cf. Pelechaty & Grotzinger, 1988; Sami &James, 1994).

Peritidal siliciclastic–carbonate faciesassociation

The peritidal siliciclastic–carbonate facies associ-ation includes four mappable facies: interbeddedsandstone and siltstone, cherty/silty dolomite–siltstone, massive sparry dolomite and fenestralmicrobial dolomite (Tables 1 and 2). The sharedfeatures of these facies include (1) abundantevidence for exposure in the form of vugs,dissolution cavities, desiccation cracks and fen-estral fabrics; (2) lack of organic-rich carbonateand shale; (3) randomly distributed, small-scalestromatolites; (4) abundant beds of siltstone and

Fig. 12. Facies of lagoonal facies association. (A) Lagoonal cycles consist of organic-rich wackestone/packstone–shale in lower part and stromatolitic dolomite in upper part, Krol C above surface 4, Nigalidhar syncline. (B)Columnar stromatolite with narrow columns and high mud content in the troughs between stromatolite heads, Krol Cabove surface 4, Mussoorie syncline. (C) Near-plan view of elongate heads of columnar stromatolites, Krol C abovesurface 4, Mussoorie syncline. (D) Large, isolated stromatolite bioherm (1 m high and 1Æ5 m wide) with high mudcontent, Krol C above surface 4, Mussoorie syncline. Scales: A (hammer), 32 cm; B–D (pencil), 14Æ5 cm.

938 G. Jiang et al.


very fine- to fine-grained sandstone; and (5) rareooids, peloids and intraclasts.

The interbedded sandstone and siltstone faciesis present in the middle part of the Infra KrolFormation below surface 2 (Fig. 4). Sandstonelayers are generally 3–20 cm thick, very fine tofine grained and well sorted. Medium-grainedquartz sandstone layers 20–30 cm thick are pre-sent locally. Ripple cross-lamination is abundant,and minor erosional surfaces are present. Relat-ively thicker sandstone layers contain shaly fla-sers and mud drapes (Fig. 7A). Siltstone-richintervals are commonly 5–30 cm thick and con-tain lenticular, 1 to 3 cm thick, fine-grainedsandstone beds. Siltstone layers are characterizedby millimetre-thick colour banding that wasconsidered by Singh (1980a) to represent tidalrhythmites. Desiccation cracks, reported from theSolan area by Bhargava & Singh (1981), were notobserved in this study.

The cherty/silty dolomite–siltstone facies isone of the most common facies in the Krol Group(Fig. 4). It consists of 0Æ5 to 4 m thick beds of greyto red siltstone and cherty/silty dolomite(Fig. 13A). Silty/cherty dolomite forms 0Æ1 to3 m thick beds of massive, partially or uniformlychertified or silicified dolomicrite and microbiallaminae. Chert nodules are concentrated alongthe bedding planes, but rarely form a continuousbed. Thin sections of the dolomite show 5–15%well-sorted quartz–muscovite silt and sandgrains. Centimetre-sized domal to columnar stro-matolites, abundant vugs, fenestral fabrics andlocally developed breccias are found in thedolomite. Siltstone layers are 0Æ5–2 m thick andcontain small-scale cross-lamination and ripplemarks (Fig. 13B). Gypsum casts and desiccationcracks (Fig. 13C) exist in both siltstone anddolomite beds.

The massive sparry dolomite facies is present asthick units in the upper Krol C below surface 5near Solan and in the upper Krol D below surface7 throughout the Lesser Himalaya (Fig. 4). Relat-ively thin units are also present in the lower KrolC below surface 4. The rocks are recrystallizedand locally brecciated. Less recrystallized inter-vals show centimetre-scale domal stromatolites,abundant vugs, fenestral fabric, vadose cementsand pisolites, dissolution cavities (Fig. 13D),zebra structure (Fig. 13E) and desiccation cracks(Fig. 13F). The sparry dolomite contains up to10% well-sorted quartz silt and sand grains.

The fenestral microbial dolomite facies is char-acterized by relatively thick dolomite layers withabundant low-relief domal and columnar stro-

matolites and unevenly distributed, spar-filledfenestrae and vugs, small dissolution cavities andchert lenses. Tepees and desiccation cracks arecommon.

InterpretationThe interbedded sandstone and siltstone facies isinterpreted to have accumulated in a shallowsubtidal to intertidal siliciclastic ramp environ-ment (Fig. 6B). Siltstone/shale layers and lenseswere deposited from suspension in a low-energysetting, possibly in a tidal flat or lagoon. A moreenergetic environment is inferred for the cross-laminated sandstone layers, which may representthe deposits of tidal subaqueous dunes or bars.This interpretation is supported by the overallstratigraphic position of the facies in the succes-sion (Fig. 7A). The upward transition from lam-inated calcareous shale and siltstone to abundantcross-laminated, well-sorted sandstone indicatesenvironments of increasing energy. However, inthe absence of three-dimensional data, it is notclear whether this facies is related to a delta front,as inferred by Bhattacharya & Niyogi (1971). It isalso not clear to what extent the environment mayhave been tidally influenced because tidal rhyth-mites and channel-form sandstone bodies, whichare characteristic of many tidal deposits (Nio &Yang, 1991), have not been observed. Rupke(1974) interpreted this facies as turbidites, butnone of the characteristic sedimentary structuresof turbidites have been found. In contrast, well-sorted, cross-laminated sandstone, flaser andlenticular bedding and locally developed desicca-tion cracks (Bhargava & Singh, 1981) suggest ashallow-water environment of deposition for thisfacies.

The cherty/silty dolomite–siltstone, massivesparry dolomite and fenestral microbial dolomitefacies are interpreted to have been deposited inintertidal to supratidal environments of bothramp and rimmed shelves (Fig. 6). The presenceof fenestral fabrics, gypsum casts, vugs, dissolu-tion cavities, vadose cements, pisolites and des-iccation cracks indicates that these facies wereformed in environments that were occasionallyexposed above sea level (cf. Pratt et al., 1992).Low-relief stromatolites, parallel microbial lam-inae and the lack of significant coarse carbonateparticles (ooids, peloids and intraclasts) suggestlow-energy, shallow-water conditions wherestromatolites might not have had enough spaceto grow. Additionally, microbial binding andcementation of the sea floor may have preven-ted the formation of particles, similar to the



widespread sea-floor algal mats of the Bahamas(Bathhurst, 1975; Hardie & Shinn, 1986). Thecherty/silty dolomite–siltstone facies may repre-sent a mixed siliciclastic–carbonate tidal flat (cf.Klein, 1971; Beukes, 1987), with a siliciclasticsource on the south-eastern side of the study area,as indicated by the increase in siliciclastic faciesin that direction (Fig. 4). It is not known to whatextent this non-carbonate sediment was intro-duced by rivers or by wind. Given the lack of land

plants in the Precambrian, it is possible thatsiliciclastic silt and sand were transported to thecarbonate tidal flats by wind and reworked bytidal action, particularly given the well-sortedquartz and muscovite silt and sand grains con-tained in the dolomite layers. Wind-blown silici-clastic particles are known to have travelledhundreds to thousands of kilometres from theirsource areas to marine carbonate environments inthe modern Persian Gulf (Shinn, 1986) and in

Fig. 13. Facies of peritidal carbonate–siliciclastic facies association. (A) Siltstone–cherty/silty dolomite alterna-tions, Krol D above surface 6, Nainital syncline. (B) Plan view of ripple marks in silty dolomite, Krol D above surface6, Nainital syncline. (C) Plan view of desiccation cracks in silty dolomite, Krol D above surface 6, Mussooriesyncline. (D) Dissolution cavities in massive sparry dolomite. Krol D above surface 7, Mussoorie syncline. (E) Zebrastructure in the massive sparry dolomite, Krol C below surface 4, Nigalidhar syncline. (F) Desiccation cracks infenestral microbial dolomite, Krol C below surface 4, Dubra, south limb of Mussoorie syncline. Scales: A (fieldassistant), 1Æ7 m high; B and C (pencil), 14Æ5 cm; D (pen), 12 cm; E (coin), 1Æ8 cm in diameter; and F (metre), 15 cm.

940 G. Jiang et al.


many ancient deposits (e.g. Dalrymple et al.,1985; Fisher & Sarnthein, 1988; Osleger &Montanez, 1996). Zebra structure is a diageneticfeature (Nielsen et al., 1998) commonly associ-ated with peritidal evaporitic sediment or sul-phides (Tompkins et al., 1994; Wallace et al.,1994). Its presence in the massive sparry dolomitefacies may indicate a saline or evaporitic deposi-tional environment.

Incised valley fills

Incised valley fills are locally present at twostratigraphic levels in the Infra Krol–Krol succes-sion: above surface 2 within the Infra KrolFormation in the Solan and Nainital areas, andabove surface 4 within the Krol C in the Nainitalarea (Fig. 4).

Siliciclastic deposits above surface 2 in thevicinity of Solan and Nainital are composed ofstacked 5 to 25 m thick, upward-fining cycles.Cycles contain coarse-grained pebbly sandstoneat the base, which is overlain by coarse- tomedium-grained sandstone, then by medium- tofine-grained sandstone and, finally, by mud-stone–siltstone (Fig. 14A and B). Although it isnot possible to trace the basal contact of thesedeposits continuously, measured sections suggestseveral metres to tens of metres of erosional relief.The sandstone is composed of well-rounded andwell-sorted quartz grains, and contains abundanttrough, tabular/planar cross-stratification, upperplane bed-parallel lamination and ripple cross-lamination.

The sandstone unit above surface 4 at Nainitalsyncline (Fig. 4) is composed of an upward-finingsuccession of greenish grey to greyish red,medium- to fine-grained, quartz sandstone andsiltstone, with dispersed carbonate clasts near thebase (Fig. 14C). Trough and tabular cross-stratifi-cation and ripple cross-lamination are present butnot common. In the cliff east of Sariatal, inter-bedded siltstone and sandstone onlaps the under-lying karstic breccia with a 10–15� difference inthe angle of dip.

InterpretationThe sandstone unit above surface 2 at Solan hasbeen variously interpreted as aeolian (Auden,1934), shallow marine (Bhattacharyya & Chanda,1971), neritic/littoral (Bhattacharya & Niyogi,1971) and intertidal to subtidal sand bars (Bhar-gava & Singh, 1981). We tentatively interpret anincised valley setting on the basis of (1) conglom-erate and sandstone units that are thicker than

those that might be ascribed to the filling offluvial or tidal channels; (2) abundant cross-bedding in the sandstone; (3) upward-finingcycles; (4) lateral thickness variations revealedby measuring multiple sections; and (5) a sharp,erosional basal contact against siltstone/shale (cf.Zaitlin et al., 1994; MacDonald et al., 1998). Thesandstone unit above surface 4 at Nainital isinterpreted as a karst valley or incised valley fillowing to the presence of karstic breccia below thesand unit. The textural and compositional matur-ity of sandstones in both examples is consistentwith deposition at least in part during marinetransgression (cf. Dalrymple et al., 1992; Zaitlinet al., 1994).

Karstic facies association

The karstic facies association includes two lith-ofacies: karstic breccia and calcrete (Tables 1 and2). These two facies are intimately related to thetwo surfaces (surface 4 and 5) that are interpretedas karstic unconformities (Fig. 4; Jiang et al.,2002).The karstic breccias are of two kinds,polymict and monomict. Polymict breccias over-lie karstic unconformities as irregular sheets orsmaller patches in topographic lows. They aretypically composed of a mixture of sharp-edgedcarbonate fragments and chert rubble, togetherwith less common blocks of pedogenic pisolite(palaeosol), claystone and green shale. Intersticesbetween blocks are filled by siltstone, sandydolomite or dolomitic sandstone; these rock typesare strongly silicified in places. Monomict brec-cias are generally associated with small caves anddykes below a karstic unconformity. They arecharacterized by relatively homogeneous clastcomposition, consistent with that of associatedin situ stratigraphy. Interstices in these brecciasare filled by sandy dolomite, siltstone or clay-stone. Polymict and monomict breccias are inter-stratified in large karstic depressions alongsurface 4, but the contacts between them arevague or gradational, and their thicknesses varylaterally.

The calcrete facies is associated with karsticbreccias at surface 5. It is expressed as thinlenses or layers overlying brecciated chertydolomite and as lenses filling small karst depres-sions. Calcrete profiles are characterized byreddish, yellowish or buff-coloured, massivesiltstone or fine- to very fine-grained sandstonedisplaying (1) micritic carbonate (dolomudstoneand lime mudstone) nodules or lenses; (2)pedogenic pisolite/ooid lenses showing reverse



grading; and (3) associated breccias, chert andiron oxide nodules.

InterpretationThe karstic facies association is interpreted torelate to karstic landforms, including karsticdepressions, caves, dykes and pockets along a

karst surface. Polymict karstic breccias are gener-ally considered as mantling breccias (Choquette &James, 1988; Kerans & Donaldson, 1988), andmonomict karstic breccias are commonly inter-preted as forming due to the collapse of caveceilings (Choquette & James, 1988; Kahle, 1988).Interstratification of these breccias in large karstic

Kro

l C

Infr

a K

rol F

orm

atio

n

Kro

l San

dsto

ne

Infr

a K

rol F

orm

atio

n

Wackestone/packstone Breccia

Parallel bedding Fining-upward

C

B

A

Organic-rich shale

Flaser bedding

Peritidal siliciclastic-carbonate Incised-valley fill Deep subtidal Karstic Lagoonal

Sandstone Green shale/siltstone Dolomite

Trough cross-stratification

Tabular/planar cross-stratification

Ripple cross-lamination

Pebbly sandstone/conglomerate

Lenticular bedding

Lime mudstone

vf f m c vcs cg

40

30

20

10

0 m

50

60

vf f m c vcs cg

40

30

20

10

0 m

50

60

vf f m c vcs cg

40

30

20

10

0 m

50

60

70

s: shale/siltstone, vf: very fine-grained, f: fine-grained, m: medium-grained, c: coarse-grained, vc: very coarse-grained; cg: conglomerate/pebbly sandstone

Fig. 14. Representative sections of incised valley fill. (A) At surface 2 near Solan, south limb of Krol syncline, northof Basal village. (B) At surface 2 at Nainital syncline, south-east of Nainital lake. (C) At surface 4, Nainital syncline,north of Runsi village.

942 G. Jiang et al.


depressions (Jiang et al., 2002) may have resultedfrom multiple stages of collapse, with mantlingbreccias being transported through a cave or karstvalley system between episodes of collapse. Thebreccias are thought to be palaeokarstic and notrelated to modern karstification. They are strati-graphically restricted, extensive but discontinu-ous. They fill fissures and are overlain with sharpcontact by younger stratigraphic units. Solutionfeatures such as pipes that might connect thebreccias with younger or modern karst are absentin the immediately overlying beds (cf. Wright,1982). Breccia fragments are reworked into over-lying ooid grainstone/packstone and, at Nainital,into sandstone.

The calcrete facies is interpreted to representpalaeosol along an exposure surface. Associatedfeatures are similar to those widely documentedin palaeosol profiles (e.g. Mustard & Donaldson,1990; Pelechaty & James, 1991; Wright, 1994).

CYCLES AND CONTROLS

Metre-scale cycles

Two types of metre-scale cycles are present in theKrol Group: stromatolitic cycles and shale-basedcycles. Stromatolitic cycles are commonly boun-ded by minor erosional surfaces, and the mostcomplete examples contain, from base to top: (1)oncoid–intraclast–ooid dolograinstone; (2) wavymicrobial laminae with intraclasts, ooids, peloidsand oncoids; (3) domal stromatolites with up-ward-increasing synoptic relief; (4) columnar

stromatolites; (5) parallel microbial laminae; and(6) fenestral microbial laminae (Fig. 10A and B).However, the abundance of the above componentfacies varies from one cycle to another. Shale-based cycles are composed of fine-grained silici-clastic lower parts and carbonate-dominatedupper parts. These cycles are interpreted to shoalupwards on the basis of upsection increases insmall-scale cross-lamination and minor erosionalsurfaces (Fig. 7B and C) or increases in grain-supported textures and stromatolitic/microbialdolomite (Fig. 10B and C).

Stromatolitic cycles are present within theperitidal carbonate complex and lagoonal faciesassociations. These cycles record a progressionfrom shallow subtidal to supratidal environ-ments. Efforts to trace cycles in the availableoutcrop at Solan and at Nigalidhar synclineshowed that they are extremely variable: thecycle boundaries disappear and componentfacies pinch out or interfinger with other faciesin < 1 km (Fig. 15). The poor traceability of thesecycles suggests an autogenic origin, in contrastto the metre-scale peritidal cycles of the Palaeo-proterozoic Rocknest platform (Grotzinger,1986b) and of the Neoproterozoic Chuar Groupin the Grand Canyon (Dehler et al., 2001), whichcan be traced over tens to hundreds of kilome-tres and are interpreted to relate to sea-levelfluctuations. Among several models for thedevelopment of autogenic cycles in peritidalenvironments (e.g. Pratt & James, 1986; Cloyd &Demicco, 1990; Sami & James, 1994), theaggrading tidal flat–island model of Sami &James (1994), modified from Pratt & James

15 m

15 m

0 100 200 300 400 500 600 700 800 m

?

Fig. 15. Tracing of cycle boundaries and component facies of stromatolitic cycles along a well-exposed cliff nearSolan. The stratigraphic interval is located between surfaces 4 and 5.



(1986), seems to provide a better interpretationfor the development of stromatolitic cycles in theKrol Group: (1) overall carbonate production andaccumulation in the peritidal complex wassufficient to track sea level so that theseenvironments remained shallow; (2) sedimentaccumulated preferentially in locally developedshallow subtidal environments, and least abun-dantly in supratidal environments; (3) because oflateral variations in the rate of carbonate pro-duction and accumulation, subtidal environ-ments were able to aggrade locally into thesupratidal zone, forming upward-shallowingcycles, and previously supratidal settings wereable to evolve into subtidal ones; (4) repetition ofthese trends resulted in a mosaic of locallydeveloped cycles. Although sea-level change isnot required to account for observed features(Fig. 15) in the above model, subsidence isneeded to create accommodation. These ideasare testable against other field examples andthrough computer modelling beyond the scopeof this paper.

Shale-based cycles are traced with difficulty inavailable outcrop, but different numbers of cyclesare observed in closely spaced sections. In theshelf lagoon deposits (Fig. 10B and C), cycles ofthis type may represent the migration of stromat-olite patch reefs or local sand bars.

Siltstone–silty/cherty dolomite alternations

Siltstone–silty/cherty dolomite alternations arecomposed of interbedded siltstone and dolomite,but do not display an unequivocal upward-shal-lowing trend and, because a systematic pattern ofthis sort is absent, we avoid the word cycle forthese deposits. The thickness of siltstone andsilty/cherty dolomite layers varies. In some cases,0Æ5 to 2 m thick, pure siltstone and 0Æ5 to 3 mthick silty/cherty dolomite constitute simple silt-stone–carbonate alternations. In other cases, thesiltstone-rich intervals contain one to three layersof 0Æ1 to 0Æ4 m thick silty/cherty dolomite. Sub-aerial exposure features such as desiccationcracks were found in both siltstone and dolomite.In the peritidal carbonate deposits, an episodicincrease followed by decrease in siliciclastic fluxcaused by climatic changes may have beenresponsible for developing these siltstone–car-bonate alternations. Variations in sediment influxof climatic origin are not necessarily in phasewith glacial-eustatic fluctuations, and are highlydependent on palaeogeographic location (Perl-mutter et al., 1998).

Non-cyclic intervals

Non-cyclic intervals are present throughout theInfra Krol Formation (with the exception of theupward-fining cycles within incised valley fills atsurface 2) and in parts of the Krol Group (Fig. 5).They are expressed as a monotonous lithologysuch as shale, thick oolitic grainstone or massivedolomite, or as interbedded siliciclastic–carbon-ate rocks lacking predictable thickness or faciesstacking patterns. The thick green/grey shale ofthe Infra Krol Formation, interbedded shale–limestone of lower Krol A and organic-richwackestone–shale above surface 4 and 5 in Garh-wal syncline (Fig. 5) are interpreted as havingbeen deposited in a subtidal shelf or deep lagoonthat was too deep to record significant changes inenvironment and facies. Intervals of more interestare those with shallow-water indicators. Grotzin-ger (1986b) and Elrick (1995) suggested that theapparent ‘non-cyclic’ interbedding of facies ofsimilar water depth results from incompleteshoaling during each ‘cycle’ owing to the effectsof long-term net increase in sea level that masksthe effects of short-term sea-level oscillations.This interpretation requires rapid long-term sea-level rise, and the non-cyclic intervals should bepresent universally in the transgressive parts ofsequences. This expectation, however, is notborne out in the Krol Group. With the exceptionof thick oolitic grainstone observed above surface4, and interpreted to have accumulated duringtransgression, non-cyclic intervals tend to under-lie karstic unconformities or other regional strat-igraphic discontinuities (Fig. 5). The absence ofcycles implies that short-term sea-level changes,if they occurred, were minimal, and abundantshallow-water features indicate deposition in asustained intertidal to supratidal environmentnot subject to the episodic introduction of silici-clastic sediment. Given the lack of precise agecontrol, the time required for the accumulation ofnon-cyclic carbonates cannot be estimated, andthe origin of the implied environmental stasis isaccordingly difficult to interpret. A possibleinterpretation is that, during the deposition ofthese non-cyclic intervals, the platform was rel-atively flat, and wide facies belts of more or lessthe same water depth and hydrodynamic condi-tion developed. If the width of facies belts waslarge compared with the lateral distance overwhich facies boundaries shifted during a partic-ular interval of time, relatively invariant faciessuccessions would result.

944 G. Jiang et al.


Cycle stacking patterns

It is widely appreciated that metre-scale cyclesshow systematic changes in cycle types, lithof-acies and thickness vertically through carbonatesuccessions, reflecting changes in accommoda-tion that may be related in some cases todifferent orders of eustatic oscillation (e.g. Gold-hammer et al., 1990, 1993; Osleger & Read, 1991;Montanez & Read, 1992; Montanez & Osleger,1993; Elrick, 1995). Upward-shallowing trendsthicker than metre-scale cycles do exist in theKrol Group (Fig. 16; see also Figs 4 and 5).However, these trends cannot be correlatedacross the platform and, more importantly, theybecome vague or disappear on the proximal sideof the platform (Mussoorie to Nainital synclines).The number of metre-scale cycles within eachupward-shallowing trend varies according topalaeogeographic location (Fig. 16). Althougheustatic change is a possible cause of observedcycle stacking patterns, differential subsidenceof the passive margin may have been responsiblefor lateral variations in the number of cycle setswithin a particular interval. Regardless of theorigin of metre-scale cycles and larger scaleupward-shallowing trends, the reliability ofcycle hierarchy for stratigraphic correlation inthe Krol seems to be limited, given the fact thatboth metre-scale cycles and their stacking pat-terns may vary according to the palaeogeogra-phic location.

PLATFORM DEVELOPMENT

Four platform geometries are suggested for theInfra Krol–Krol interval: (1) siliciclastic ramp;(2) carbonate ramp; (3) peritidal rimmed shelf;and (4) open shelf. Because no slope/basinalfacies crop out in the Lesser Himalaya, thedifferentiation of ramp and open shelf is tenta-tive.

Siliciclastic ramp

The Infra Krol Formation is thought to haveaccumulated at a siliciclastic ramp that devel-oped atop the glacial-marine diamictites of theBlaini Formation (Fig. 17A). The abrupt litho-logical transition is consistent with rapidsea-level rise and sediment starvation duringdeglaciation, and a palaeoenvironment mostlybelow fairweather wave base. Facies werestacked aggradationally for most of the time,

with representative lithologies of thinly lamin-ated calcareous shale and siltstone. In the latestages, progradation resulted in the deposition ofsiltstone and fine-grained sandstone (Figs 7Aand 17B).

Carbonate ramp

The carbonate ramp represented by the upperpart of Krol A to lower Krol C inherited thegeometry of the siliciclastic ramp. Initiation ofcarbonate production may have been related toreduced siliciclastic influx, either climaticallyinduced or resulting from lowering of the topog-raphy in the hinterland of the platform. Thedeep subtidal ramp (Fig. 17C) is represented byshale–limestone rhythmites, and the peritidalramp (Fig. 17D) by interbedded siltstone anddolomite (Krol B) and massive dolomite (lowerKrol C). Lateral facies variation is limited, con-sistent with the absence of reefs, shoals or otherpalaeogeographic complexity.

Peritidal rimmed shelf

Basal deposits of the peritidal rimmed shelfaccumulated above the pre-existing low-gradientramp (Fig. 17D). The rimmed shelf was charac-terized by a persistent accretionary reefal rim(inferred) and a peritidal, stromatolite-rich car-bonate complex over a widespread sand shoal(Fig. 17E). Increased carbonate production andaccumulation in the complex led to the develop-ment of a deepening and increasingly restrictedshelf lagoon. Expansion of the complex into theshelf lagoon was localized, possibly because ofnutrient limitation (cf. Schlager, 1981). Locallydeveloped sand shoals or bars and stromatolitepatch reefs formed bathymetric highs in thelagoon. Siliciclastic influx from the south-easternside of the shelf eventually led to progradation ofthe peritidal complex, and shut down the car-bonate factory, leading in turn to the drowning ofthe platform (Fig. 17F).

Open shelf

The interval from surface 6 to surface 8 istentatively interpreted to represent an open shelf(or distally steepened ramp of Read, 1985), giventhat the platform evolved from a rimmed shelf.The shelf rim and peritidal complex were not ableto be re-established after the flooding event,possibly because of the increased siliciclasticpollution (Fig. 17G and H).



0-2 m thick

slm

wp

gd

slm

wp

gd

4

5

0 m

20

40

60

80

100

120

140

160

180

200

220

Solan Nigalidhar Nainital

Shallowing-upward

Non-cyclic interval

Lithological alternation

Fining-upward

0-15 m thick

0-1 m thick

0-10 m thick

0-1 m thick

0-10 m thick

slm

wp

gd

Fig. 16. Example of cycles and their stacking patterns for the interval between surfaces 4 and 5.

946 G. Jiang et al.


Termination of the Krol platform

During the final phase of evolution, the Krolplatform was drowned and buried by deep-water,phosphorite-bearing shale and bedded chert ofthe basal Tal Group and, in turn, by up to 2500 mof shallow-marine to fluvial siliciclastic deposits(Singh & Rai, 1983).

NEOPROTEROZOIC PASSIVE MARGINOF NORTHERN INDIA

The Neoproterozoic strata of the Lesser Himalayahave been interpreted as deposits of an isolatedbasin centred in Mussoorie syncline, with itswestern margin in the Krol Hills and easternmargin in the vicinity of Nainital (e.g. Shanker

?

???

??

Sand shoal: oolitic grainstone

?

Slope-basinal shale ?

??

MSL

FWB

SWB

??

??

?

??

?

??

??

MSL

FWB

SWB

MSL

Solan Nainital>250 km?

MSLFWBSWB

??

(A)

(B)

(C)

(D)

(E)

(F)

(G)

(H)

(I)

Sili

cicl

astic

Ram

pC

arbo

nate

Ram

pP

eriti

dal r

imm

ed s

helf

Car

bona

te o

pen

shel

f

?

?

?

??

?

Peritidal carbonate:massive sparry dolomite

Shallow to deep subtidal: interbedded shale and limestone

Peritidal siliciclastic: interbedded sandstone and siltstone

Deep subtidal siliciclastic: calcareous shale/siltstone

Peritidal complex: wavy microbial dolomite, stromatolitic dolomite, fenestral microbial dolomite, Oncoid/intraclastic dolograinstone

Stromatolite reef?

Shelf lagoon: organic-rich shale and packstone/wackestone, stromatolitic dolomite

Peritidal siliciclastic-carbonate: cherty/silty dolomite-siltstone

Peritidal carbonate: microbial dolomite

Subtidal: calcareous shale, dolopackstone/wackestone-siltstone

MSL

FWB

SWB

Mean sea level

Fairweather wave base

Storm wave base

??

FWBSWB

?

?

?

?

Fig. 17. Summary of platform evolution. (A and B) Siliciclastic ramp (Infra Krol Formation to lower Krol A). (C andD) Carbonate ramp (upper Krol A to lower Krol C). (E–G) Peritidal rimmed shelf (middle Krol C to Krol D). (H and I)Open shelf (upper Krol D to Krol E). See text for interpretation.



et al., 1989; Virdi, 1991; Shanker & Mathur, 1992),or an isolated basin with its northern margin in thepresent-day High Himalaya and its southernmargin connecting with the Vindhyan basin (e.g.Bhattacharya, 1982; Saxena, 1981). In contrast,Brookfield (1993) suggested that the stratigraphicrecord represents the inner part of a north-facingpassive continental margin. The main evidenceoffered in support of the isolated basin interpret-ation is that (1) the thickness of the Krol and Talgroups attains a maximum in Mussoorie syncline;and (2) similar lithofacies are not present in theHigh Himalaya. However, our stratigraphic stud-ies indicate that the reported thickness variationof the Krol Group is influenced by a combinationof incomplete exposure and tectonic repetition(Jiang et al., 2002). Facies analysis of the Infra KrolFormation and Krol Group reported here reveals aplatform architecture that is more consistent withthe existence of a north- to north-west-facingpassive margin.

The Neoproterozoic rift to passive margin suc-cession in the Lesser Himalaya is summarized in

Fig. 18. The basal part of the succession is repre-sented by the Jaunsar Group in the south-eastern-most synclines and by the Simla Group in thenorth-west. These units unconformably overliethe Mesoproterozoic metamorphic rocks assignedto the Berinag Quartzite in the south-east andShali Group near Simla, where intrusive rocksdated as 823 ± 5 Ma have been reported (Singhet al., 2002). Facies analysis reveals an overallfining towards the north-west, from fluvial- andcoastal plain-dominated sandstone and conglom-erate (Nagthat Formation) at Nainital syncline toshoreface- and inner-shelf siltstone and sandstone(Chandpur and Nagthat formations) in Garhwal toNigalidhar synclines (Ghosh, 1991) and to muddydelta-front and outer-shelf shale/siltstone andsandstone (Simla Group) at Simla (Kumar &Brookfield, 1987). Turbidites have been reportedwithin the latter (Valdiya, 1970). An erosionalunconformity has been documented at or near theChandpur/Nagthat contact (Pant & Shukla, 1999).Rift-related mafic volcanic rocks and tuff/tuffa-ceous sandstone are present in north-western

Sim

la G

rou

p

BL–Blaini Formation

NT

CH

ABCDEFGHSENW

?

NT

Jau

nsa

r G

rou

p

Rif

t B

asin

Pas

sive

Mar

gin

BL

IN+K

R

Mesoproterozoic metamophic rocks Intrusive rocks

Shoreface/inner-shelf SandstoneFluvial/coastal plain conglomerate

Outer-shelf/basinal siltstone and sandstone Glacial marine diamictite

Siliciclastic-carbonate ramp facies

Peritidal stromatolite-rich complex Shelf-lagoon and tidal flat facies

Open shelf carbonate-siliciclastic facies Slope-basinal facies

NT–Nagthat Formation IN+KR–Infra Krol Formation and Krol GroupCH–Chandpur Formation

Mes

op

rote

rozo

icN

eop

rote

rozo

ic

1000 m

100200 km

500 m

Interglacial siltstone and sandstone

823+ 5Ma

Volcanic+ ++

++

771-751 Ma ?

+ +

Fig. 18. Neoproterozoic stratigraphy and basin evolution of the Lesser Himalaya, northern India. Measured sections(A–G) located in Fig. 1. Stratigraphy of section H (Simla) is summarized from Valdiya (1970) and Kumar & Brookfield(1987). The geology north-west of Simla (question mark) is inferred from our stratigraphic analysis. U-Pb age of823 ± 5 Ma intrusive rocks from Singh et al. (2002) and 771–751 Ma age of Malani igneous rocks from Torsvik et al.(2001).

948 G. Jiang et al.


areas, and U-Pb ages of 771 ± 2 and 751 ± 3 Mahave been reported (Torsvik et al., 2001). Uncon-formably overlying the Jaunsar and Simla groupsare diamictite, siltstone and sandstone of inferredglacial and glacial-marine origin (Blaini Forma-tion). This unit has three lithologically distin-guishable parts: a lower diamictite-rich partcomprising three to four massive diamictite inter-vals separated by siltstone/mudstone; a middlesiltstone and sandstone part with occasionallenses or thin layers of ferruginous shale; and anupper diamictite with an erosional unconformityat its base. Although the Blaini Formation is notdirectly dated, the two diamictite-rich intervalsmay represent records of the two most widespreadNeoproterozoic glaciations: the Sturtian andMarinoan or Varanger events.

The stratigraphic location of the rift to passive-margin transition is uncertain, but is tentativelyinterpreted within or perhaps at the base of theglacigenic units (Fig. 18). A passive margin set-ting for the post-glacial carbonate strata describedin this paper is inferred on the basis of scale, theabsence of igneous rocks and comparativelysimple facies and thickness trends, with noevidence for substantial syndepositional tecton-ism comparable to that of foreland basins (cf.Plint et al., 1993).

In the High Himalaya, a Neoproterozoic suc-cession comparable to that of the Lesser Himalayahas not been documented, and the absence ofsuch a succession has been used to supportthe argument that the basin now exposed in theLesser Himalaya was isolated. However, theapparent absence of equivalent units in the HighHimalaya is mainly a statement about lithicmismatch of poorly dated rocks. It is predictedhere that, if correlative rocks are present in theHigh Himalaya, they should be composed of fine-grained siliciclastic and carbonate slope andbasinal deposits very different from the plat-formal carbonate rocks of the Lesser Himalaya(Fig. 18).

Overlying the carbonate deposits of the Krolplatform of the Lesser Himalaya are lower Cam-brian siliciclastic rocks (Tal Group), which areunconformably overlain in turn by Permianstrata. In the High Himalaya, however, middleCambrian to Carboniferous rocks have beenrecognized, as well as the evidence for earlyOrdovician deformation and granite intrusion(e.g. Brookfield, 1993). One interpretation is that,after the early Cambrian, the Lesser Himalaya wasuplifted, shifting the depocentre towards thenorth. This may have been related to the collision

between India and East Antarctic between � 550to � 525 Ma (e.g. Torsvik et al., 2001).

SUMMARY

Detailed studies of facies and facies associationsreveal that the terminal Proterozoic Infra Krol–Krol succession of northern India represents anorth- to north-west-facing carbonate platform, aninterpretation that departs markedly from exist-ing depositional models for these rocks. Theplatform evolved from a siliciclastic ramp, tocarbonate ramp, to peritidal rimmed shelf to openshelf. The peritidal carbonate complex of therimmed shelf is analogous to platform marginreefs of the Phanerozoic, separating and restrict-ing a shelf lagoon from the open ocean.

Stromatolitic cycles, shale-based cycles andsiltstone–silty/cherty dolomite alternations arepresent in the Krol Group. The cycles and appar-ently ‘cyclic’ lithic alternations are laterally dis-continuous, and are thought to be primarilyautogenic. Stromatolitic cycles are interpreted tohave formed by facies migration related to vari-able carbonate production. Shale-based cycles areinterpreted to have formed through the migrationof locally developed carbonate sand shoals or barsor stromatolite patch reefs. Siltstone–silty/chertydolomite alternations developed as a result ofepisodic siliciclastic influx from the proximalside of the shelf lagoon. Eustatic fluctuations areneither required nor precluded for these alterna-tions. Non-cyclic intervals suggest that thedimensions of any particular substrate were largecompared with the scale of lateral shifts in facies.Cycle stacking patterns are shown to changeacross the platform, possibly owing to the differ-ential subsidence of the passive margin.

The overall Neoproterozoic succession of theLesser Himalaya is interpreted to represent a riftbasin to passive margin, with rift to post-rifttransition located within or perhaps at the base ofthe glacial unit (Blaini Formation). EquivalentNeoproterozoic successions in the High Hima-laya, if preserved, may be mainly slope/basinalfacies represented by fine-grained siliciclastic andcarbonate rocks, lithologically different fromthose of the Lesser Himalaya.

ACKNOWLEDGEMENTS

We are especially grateful to R. Shanker (Geolo-gical Survey of India), I. B. Singh and S. Kumar



(Lucknow University), V. C. Tewari (WadiaInstitute), O. P. Goel and S. B. Misra (KumunUniversity) for stimulating discussions and foradvice about sections suitable for this study. Wethank Sidney Hemming and Paul Olsen, journalreviewers Paul Myrow and David Osleger, andIsabel Montanez (editor) for constructive com-ments that helped to improve the paper signifi-cantly. The research was supported by NationalScience Foundation Grant EAR 96-14070. Lam-ont-Doherty Earth Observatory ContributionNumber 6465.

REFERENCES

Auden, J.B. (1934) The geology of the Krol belt. Geol. Surv.

India Rec., 71, 357–454.

Bathhurst, R.G.C. (1975) Carbonate Sediments and Their

Diagenesis. Elsevier, Amsterdam, 658 pp.

Beukes, N.J. (1987) Facies relations, depositional environ-

ments and diagenesis in a major Proterozoic stromatolitic

carbonate platform to basinal sequence, Campbellrand

Supergroup, Transvaal Supergroup, southern Africa. Sed.

Geol., 54, 1–46.

Bhargava, O.N. (1979) Lithostratigraphic classification of the

Blaini, Infra-Krol, Krol and Tal formations: a review. J. Geol.

Soc. India, 20, 7–16.

Bhargava, A.K. and Singh, I.B. (1981) Some paleoenviron-

mental observations on the Infra Krol Formation, Lesser

Himalaya. J. Paleontol. Soc. India, 25, 26–32.

Bhatt, D.K. (1991) The Precambrian-Cambrian transition

interval in Himalaya with special reference to small shelly

fossils – a review of current status of work. J. Palaeontol.

Soc. India, 36, 109–120.

Bhattacharya, A.R. (1982) The Lesser Himalaya sediments:

Precambrian span. In: Geology of Vindhyanchal (Eds K.S.

Valdiya, S.B. Bhatia and V.K. Gaur), pp. 200–210. Hindu-

stan Publishing Corporation, Delhi, India.

Bhattacharyya, A. and Chanda, S.K. (1971) Petrology and

origin of the Krol Sandstone around Solan, Himachal

Pradesh. J. Geol. Soc. India, 12, 368–374.

Bhattacharya, S.C. and Niyogi, D. (1971) Geological evolution

of the Krol Belt in Simla Hills, H.P. Himalayan Geol., 1,178–212.

Bosence, D.W.J., Wood, J.L., Rose, E.P.F. and Qing, H. (2000)

Low- and high-frequency sea-level changes control peritidal

carbonate cycles, facies and dolomitization in the Rock of

Gibraltar (Early Jurassic, Iberian Peninsula). J. Geol. Soc.

London, 157, 61–74.

Brookfield, M.E. (1993) The Himalayan passive margin from

Precambrian to Cretaceous times. Sed. Geol., 84, 1–35.

Burne, R.V. and Moore, L.S. (1987) Microbialites: organosed-

imentary deposits of benthic microbial communities. Pala-

ios, 2, 241–254.

Choquette, P.W. and James, N.P. (1988) Introduction. In:

Paleokarst (Eds J.P. James and P.W. Choquette), pp. 1–21.

Springer-Verlag, New York.

Cloyd, K.C. and Demicco, R.V. (1990) Tidal channel, levee,

and crevasse-splay deposits from a Cambrian tidal channel

system: a new mechanism to produce shallowing-upward

sequences. J. Sed. Petrol., 60, 73–83.

Crowell, J.C. (1999) Pre-Mesozoic ice ages: their bearing on

understanding the climate system. Geol. Soc. Am. Mem.,

192, 45–66.

Dalrymple, R.W., Narbonne, G.M. and Smith, L. (1985) Eolian

action and the distribution of Cambrian shales in North

America. Geology, 13, 607–610.

Dalrymple, R.W., Zaitlin, B.A. and Boyd, R. (1992) Estuarine

facies models: conceptual basis and stratigraphic implica-

tions. J. Sed. Petrol., 62, 1130–1146.

Dehler, C.M., Elrick, M., Karlstrom, K.E., Smith, G.A., Gros-sey, L.J. and Timmons, J.M. (2001) Neoproterozoic Chuar

Group (�800–742 Ma), Grand Canyon: a record of cyclic

marine deposition during global cooling and supercontinent

rifting. Sed. Geol., 141–142, 465–499.

Elrick, M. (1995) Cyclostratigraphy of Middle Devonian car-

bonates of the eastern Great Basin. J. Sed. Res., B65, 61–79.

Feldmann, M. and McKenzie, J.A. (1998) Stromatolite–

thrombolite associations in a modern environment, Lee

Stocking Island, Bahamas. Palaios, 13, 201–212.

Fisher, A.G. and Sarnthein, M. (1988) Airborne silts and

dune-derived sands in the Permian of the Delaware Basin.

J. Sed. Petrol., 58, 637–643.

Ghosh, S.K. (1991) Paleoenvironmental analysis of the Late

Proterozoic Nagthat Formation, NW Kumaun Lesser Hima-

laya, India. Sed. Geol., 71, 33–45.

Goldhammer, R.K., Dunn, P.A. and Hardie, L.A. (1990)

Depositional cycles, composite sea level changes, cycle

stacking patterns, and the hierarchy of stratigraphic forcing

– examples from platform carbonates of the Alpine Triassic.

Geol. Soc. Am. Bull., 102, 535–562.

Goldhammer, R.K., Lehmann, P.J. and Dunn, P.A. (1993) The

origin of high-frequency platform carbonate cycles and

third-order sequences (Lower Ordovician El Paso Gp, west

Texas): constraints from outcrop data and stratigraphic

modeling. J. Sed. Petrol., 63, 318–359.

Grotzinger, J.P. (1986a) Evolution of Early Proterozoic passive-

margin carbonate platform, Rocknest Formation, Wopmay

Orogen, Northwest Territories, Canada. J. Sed. Petrol., 56,831–847.

Grotzinger, J.P. (1986b) Cyclicity and paleoenvironmental

dynamics, Rocknest platform, northwest Canada. Geol. Soc.Am. Bull., 97, 1208–1231.

Grotzinger, J.P. (1989a) Construction of early Proterozoic (1.9

GA) barrier reef complex, Rocknest Platform, Northwest

Territories. In: Reefs – Canada and Adjacent Areas (Eds

H. Geldsetzer, N.P. James and G. Tebbut), Can. Soc. Petrol.

Geol. Mem., 13, 30–37.

Grotzinger, J.P. (1989b) Facies and evolution of Precambrian

depositional systems: emergence of the modern platform

archetype. In: Controls on Carbonate Platform and Basin

Development (Eds P.D. Crevello, J.L. Wilson, J.F. Sarg and

J.F. Read), SEPM Spec. Publ., 44, 79–106.

Grotzinger, J.P. and James, N.P. (2000) Precambrian carbon-

ates: evolution of understanding. In: Carbonate Sedimen-

tation and Diagenesis in the Evolving Precambrian World

(Eds J.P. Grotzinger and N.P. James), SEPM Spec. Publ., 67,3–20.

Hardie, L.A. and Shinn, E.A. (1986) Carbonate depositional

environments, Part 3: Tidal flats. Colorado School Mines Q.,81, 1–74.

Hodges, K.V. (2000) Tectonics of the Himalaya and southern

Tibet from two perspectives. Geol. Soc. Am. Bull., 112, 324–

350.

Hoffman, P.F. (1989) Pethei reef complex (1.9 Ga), Great Slave

Lake, N.W.T. In: Reefs – Canada and Adjacent Areas (Eds

950 G. Jiang et al.


H. Geldsetzer, N.P. James and G. Tebbutt), Can. Soc. Petrol.

Geol. Mem., 13, 38–48.

Hoffman, P.F., Kaufman, A.J., Halverson, G.P. and Schrag,D.P. (1998) A Neoproterozoic snowball earth. Science, 281,1342–1346.

Holland, S.M. and Patzkowsky, M.E. (1998) Sequence strati-

graphy and relative sea-level history of the Middle and

Upper Ordovician of the Nashville Dome, Tennessee. J. Sed.Res., 68, 684–699.

Jiang, G., Christie-Blick, N., Kaufman, A.J., Banerjee, D.M.and Rai, V. (2002) Sequence stratigraphy of the terminal

Proterozoic Krol Group and Infra Krol Formation, Lesser

Himalaya, India. J. Sed. Res., 72, 524–542.

Kahle, C.F. (1988) Surface and subsurface paleokarst, Silurian

Lockport, and Peebles Dolomites, Western Ohio. In:

Paleokarst (Eds J.P. James and P.W. Choquette), pp. 229–

235. Springer-Verlag, New York.

Kaufman, A.J., Knoll, A.H. and Narbonne, G.M. (1997) Iso-

topes, ice ages, and terminal Proterozoic earth history. Proc.Natl. Acad. Sci. USA, 94, 6600–6605.

Kennedy, M.J., Runnegar, B., Prave, A.R., Hoffmann, K.H. and

Arthur, M.A. (1998) Two or four Neoproterozoic glacia-

tions? Geology, 26, 1059–1063.

Kerans, C. and Donaldson, J.A. (1988) Proterozoic paleokarst

profile, Dismas Lakes Group, N.W.T., Canada. In: Paleokarst

(Eds J.P. James and P.W. Choquette), pp. 167–182. Springer-

Verlag, New York.

Klein, G.deV. (1971) A sedimentary model for determining

paleotidal range. Geol. Soc. Am. Bull., 82, 2585–2592.

Kumar, G., Bhatt, D.K. and Raina, B.K. (1987) Skeletal

microfauna of Meishucunian and Qiongzhusian (Precam-

brian–Cambrian boundary) age from the Ganga Valley,

Lesser Himalaya, India. Geol. Mag., 124, 167–171.

Kumar, R. and Brookfield, M.E. (1987) Sedimentary environ-

ments of the Simla Group (upper Precambrian), Lesser

Himalaya,andtheirpaleotectonicsignificance.Sed.Geol.,52,27–43.

MacDonald, A.C., Falt, L.M. and Hektoen, A.L. (1998) Stoch-

astic modeling of incised valley geometries. AAPG Bull., 82,1156–1172.

Mathur, V.K. and Shanker, R. (1989) First record of Ediacaran

fossils from the Krol Formation, Nainital syncline. J. Geol.Soc. India, 34, 245–254.

Mathur, V.K. and Shanker, R. (1990) Ediacaran medusoids

from Cambrian Tal Formation, Himachal Lesser Himalaya

and the Krol Formation, Naini Tal syncline. J. Geol. Soc.India, 36, 74–78.

Montanez, I.P. and Osleger, D.A. (1993) Parasequence stacking

patterns, third-order accommodation events, and sequence

stratigraphy of Middle to Upper Cambrian platform car-

bonates, Bonanza King Formation, southern Great basin. In:

Carbonate Sequence Stratigraphy – Recent Developments

and Applications (Eds R.B. Loucks and J.F. Sarg), AAPGMem.,57, 305–325.

Montanez, I.P. and Read, J.F. (1992) Eustastic sea-level control

on early dolomitization of peritidal carbonates: evidence

from the Early Ordovician, Upper Knox Group, Appalachi-

ans. Geol. Soc. Am. Bull., 104, 872–886.

Mustard, P.S. and Donaldson, J.A. (1990) Paleokarst breccias,

calcretes, silcretes and fault breccias at the base of Upper

Proterozoic ‘Windermere’ strata, northern Canadian Cor-

dillera. J. Sed. Petrol., 60, 525–539.

Najman, Y. and Garzanti, E. (2000) Reconstructing early

Himalaya tectonic evolution and paleogeography from

Tertiary foreland basin sedimentary rocks, northern India.

Geol. Soc. Am. Bull., 112, 435–449.

Nielsen, P., Swennen, R., Muchez, P.H. and Keppens, E.(1998) Origin of Dinantian zebra dolomites south of the

Brabant-Wales Massif, Belgium. Sedimentology, 45, 727–

743.

Nio, S.D. and Yang Chang-Shu (1991) Diagnostic attributes of

clastic tidal deposits: a review. In: Clastic Tidal Sedimen-

tology (Eds D.G. Smith, G.E. Reinson, B.A. Zaitlin and

R.A. Rahmani), Can. Soc. Petrol. Geol. Mem., 16, 3–28.

Osleger, D.A. and Montanez, I.P. (1996) Cross-platform

architecture of a sequence boundary in mixed siliciclastic-

carbonate lithofacies, Middle Cambrian, southern Great

Basin, USA. Sedimentology, 43, 197–217.

Osleger, D.A. and Read, J.F. (1991) Relation of eustasy to

stacking patterns of meter scale carbonate cycles, Late

Cambrian, USA. J. Sed. Petrol., 61, 1225–1252.

Pant, C.C. and Shukla, U.K. (1999) Nagthat Formation: An

example of a progradational, tide-dominated Proterozoic

succession in Kumaun Lesser Himalaya, India. J. SE Asian

Earth Sci., 7,353–368.

Pelechaty, S.M. and Grotzinger, J.P. (1988) Stromatolites bio-

herms of a 1.9 Ga foreland basin carbonate ramp, Beechey

Formation, Kilohigok Basin, Northwest Territories. In: Reefs– Canada and Adjacent Areas (Eds H. Geldsetzer, N.P.

James and G. Tebbut), Can. Soc. Petrol. Geol. Mem., 13,93–104.

Pelechaty, S.M. and James, N.P. (1991) Dolomitized Middle

Proterozoic calcretes, Bathurst Inlet, northwest Territories,

Canada. J. Sed. Petrol., 61, 988–1001.

Pelechaty, S.M., Grotzinger, J.P., Kashirtsev, V.A. and Zher-novsky, V.P. (1996) Chemostratigraphic and sequence

stratigraphic constraints on Vendian–Cambrian basin

dynamics, northeast Siberian craton. J. Geol., 104, 543–564.

Perlmutter, M.A., Radovich, B.J., Matthews, M.D. and

Kendall, C.G.St. C. (1998) The impact of high-frequency

sedimentation cycles on stratigraphic interpretation. In:

Sequence Stratigraphy – Concepts and Applications (Eds

F.M. Gradstein, K.O. Sandvik and N.J. Milton), pp. 141–170.

Elsevier, Amsterdam.

Plint, A.G., Hart, B.S. and Donaldson, W.S. (1993) Litho-

sphere flexture as a control on stratal geometry and facies

distribution in Upper Cretaceous rocks of the Alberta fore-

land basin. Basin Res., 5, 69–77.

Powers, P.M., Lillie, R.J. and Yeats, R.S. (1998) Structure and

shortening of the Kangra and Dehra Dun re-entrants, Sub-

Himalaya, India. Geol. Soc. Am. Bull., 110, 1010–1027.

Pratt, B.R. and James, N.P. (1986) The St George Group (Lower

Ordovician) of western Newfoundland: tidal flat island

model for carbonate sedimentation in shallow epeiric seas.

Sedimentology, 33, 313–343.

Pratt, B.R., James, N.P. and Cowan, C.A. (1992) Peritidal

carbonates. In: Facies Models: Response to Sea Level

Changes (Eds R.G. Walker and N.P. James), Geol. Assoc.Can., 303–322.

Read, J.F. (1985) Carbonate platform facies models. AAPG

Bull., 69, 1–21.

Rupke, J. (1974) Stratigraphic and structural evolution of the

Kumaon Lesser Himalaya. Sed. Geol., 11, 81–265.

Sami, T.T. and James, N.P. (1993) Evolution of an early Pro-

terozoic foreland basin carbonate platform, lower Pethei

Group, Great Slave Lake, north-west Canada. Sedimentology,

40, 403–430.

Sami, T.T. and James, N.P. (1994) Peritidal carbonate platform

growth and cyclicity in an early Proterozoic foreland basin,

Upper Pethei Group, northwest Canada. J. Sed. Res., B64,111–131.



Saxena, M.N. (1981) Chronology of tectonic events of the

Himalaya. In: Metamorphic Tectonites of the Himalaya

(Ed. P.S. Saklani), pp. 303–348. Today and Tomorrow’s

Publishers, New Delhi.

Schieber, J. (1994) Evidence for high-energy events and shal-

low-water deposition in the Chattanooga Shale, Devonian,

central Tennessee, USA. Sed. Geol., 93, 193–208.

Schieber, J. (1999) Distribution and deposition of mudstone

facies in the upper Devonian Sonyea Group of New York.

J. Sed. Res., 69, 909–925.

Schlager, W. (1981) The paradox of drowned reefs and car-

bonate platforms. Geol. Soc. Am. Bull., 92, 197–211.

Shanker, R. and Mathur, V.K. (1992) Precambrian–Cambrian

sequence in Krol Belt and additional Ediacaran fossils.

Geophytology, 22, 27–39.

Shanker, R., Kumar, G. and Saxena, S.P. (1989) Stratigraphy

and sedimentation in Himalaya, a reappraisal. Geol. Surv.

India Spec. Publ., 26, 1–60.

Shanker, R., Kumar, G., Mathur, V.K. and Johsi, A. (1993)

Stratigraphy of Blaini, Infra Krol and Tal succession, Krol

Belt, Lesser Himalaya. Indian J. Petrol. Geol., 2, 99–136.

Shanker, R., Mathur, V.K., Kumar, G. and Srivastava, M.C.(1997) Additional Ediacaran biota from the Krol Group,

Lesser Himalaya, India and their significance. Geosci. J., 18,79–91.

Shinn, E.A. (1986) Modern carbonate tidal flats: their diag-

nostic features. In: Carbonate Depositional Environments.

Part 3. Tidal Flats (Eds L.A. Hardie and E.A. Shinn),

Colorado School Mines Q., 81, 7–35.

Singh, I.B. (1980a) Sedimentological evolution of the Krol Belt

sediments. Himalayan Geol., 8, 657–683.

Singh, I.B. (1980b) Precambrian sedimentary sequences of

India: their peculiarities and comparison with modern

sediments. Precambrian Res., 12, 411–436.

Singh, I.B. and Rai, V. (1980) Some observations on the

depositional environment of the Krol Formation in Nainital

area. Himalayan Geol., 8, 633–656.

Singh, I.B. and Rai, V. (1983) Fauna and biogenic structures in

Krol-Tal succession (Vendian–Early Cambrian), Lesser

Himalaya and a biostratigraphic and palaeontological sig-

nificance. J. Paleontol. Soc. India, 28, 67–90.

Singh, I.B., Rai, V. and Bhargava, A.K. (1980) Some obser-

vations on the sedimentology of the Krol succession of

Mussoorie area, Uttar Pradesh. J. Geol. Soc. India, 21, 232–

238.

Singh, S., Barley, M.E., Brown, S.J., Jain, A.K. and Manic-kavasagam, R.M. (2002) SHRIMP U-Pb in zircon geochro-

nology of the Chor granitoid: evidence for Neoproterozoic

magmatism in the Lesser Himalayan granite belt of NW

India. Precambrian Res., 118, 285–292.

Sohl, L.E., Christie-Blick, N. and Kent, D.V. (1999) Paleo-

magnetic polarity reversals in Marinoan (�600 Ma) glacial

deposits of Australia: implications for the duration of low-

latitude glaciation in Neoproterozoic time. Geol. Soc. Am.Bull., 111, 1120–1139.

Southgate, P.N. (1989) Relationships between cyclicity and

stromatolite form in the Late Proterozoic Bitter Springs

Formation, Australia. Sedimentology, 36, 323–339.

Sweet, K. and Knoll, A.H. (1989) Marine pisolites from Upper

Proterozoic carbonates of East Greenland and Spitsbergen.

Sedimentology, 36, 75–93.

Tangri, A.K. and Singh, I.B. (1982) Palaeoenvironment of

Blaini Formation, Lesser Himalaya. J. Paleontol. Soc. India,

27, 35–48.

Tiwari, M. and Knoll, A.H. (1994) Large acanthomorphic a-

critarchs from the Infrakrol Formation of the Lesser Hima-

laya and their stratigraphic significance. J. Himalayan Geol.,

5, 193–201.

Tompkins, L.A., Murray, J.R., Groves, D.I. and Roche, M.T.(1994) Evaporites: in situ sulfur source for rhythmically

banded ore in the Cadjebut Mississippi Valley-type Zn-Pb

deposits, Western Australia. Econ. Geol., 89, 467–492.

Torsvik, T.H., Carter, L.M., Ashwal, L.D., Bhushan, S.K.,Pandit, M.K. and Jamtveit, B. (2001) Rodinia refined or

obscured: palaeomagnetism of the Malani igneous suite

(NW India). Precambrian Res., 108, 319–333.

Valdiya, K.S. (1970) Simla Slates: the Precambrian Flysch of

the Lesser Himalaya, its turbidites, sedimentary structures

and paleocurrents. Geol. Soc. Am. Bull., 81, 451–468.

Virdi, N.S. (1991) Sedimentation and tectonics of the Krol belt

– control of basement structures on the basin configuration.

J. Himalayan Geol., 2, 141–149.

Wallace, M.W., Both, R.A., Ruano, S.M., Hach-Ali, P.F. and

Lees, T. (1994) Zebra textures from carbonate-hosted sulfide

deposits: sheet cavity networks produced by fracture and

solution enlargement. Econ. Geol., 89, 1183–1191.

Wright, V.P. (1982) The recognition and interpretation of

paleokarsts: two examples from the Lower Carboniferous of

south Wales. J. Sed. Petrol., 52, 83–94.

Wright, V.P. (1994) Paleosols in shallow marine carbonate

sequences. Earth-Sci. Rev., 35, 367–395.

Zaitlin, B.A., Dalrymple, R.W. and Boyd, R. (1994) The strati-

graphic organization of incised-valley systems associated

with relative sea-level change. In: Incised Valley Systems:

Origin and Sedimentary Sequences (Eds R. Dalrymple,

R. Boyd and B. Zaitlin), SEPM Spec. Publ., 51, 45–60.

Manuscript received 25 October 2002;revision accepted 20 May 2003.


952 G. Jiang et al.

carbonate platform growth and cyclicity at a …kaufman/pdf/jiang_03.pdfcarbonate platform growth...

Documents