Chapter -5

Taphonomy

125

5.1 Introduction

The term “taphonomy” was originally defined by paleontologist Efremov

(1940) as “the study of the transition (in all its details) of animal remains from the

biosphere into the lithosphere”. Taphonomic facies are suites of fossils in sedimentary

rocks that are defined by specific preservational characteristics (Brett and Baird,

1986; Brett and Speyer, 1990). It helps in understanding the restrictions of the fossil

record; taphonomic studies have made important contributions to the interpretation of

depositional environments. The importance of taphonomy as a tool for

palaeoenvironmental reconstruction has been increasingly recognized (e.g. Kidwell et

al. 1986; Norris, 1986; Kidwell, 1991; Kidwell and Holland, 1991). Shell

concentration, also known as shell bed or coquina bed, is defined as any relatively

dense accumulation of coarse (>2 mm) bioclasts or bio mineralized remains from any

invertebrates (Kidwell, 1991). As a complex repository of biostratigraphic and

palaeoenvironmental data, it is a potential source of information about depositional

history of a basin. Shell concentrations can form thick beds if shell input is more than

the shell loss by physical, chemical or biological processes. Their formation and

distribution in the stratigraphic section are directly controlled by biogenic production

and rate of background sedimentation. They may form in the life habitat of the

organisms or may accumulate outside the life habitat as reworked concentration

(Kumar et al., 2009). Taphonomic aspect or shell accumulation provides intricate

details of the process responsible for its deposition by analyzing the fossil content.

The analysis thus also suggest whether the fossils fauna present in the shell

accumulation was from the same habitat or from exotic habitat beyond the

depositional setting. Such type of integrated helps in understanding the important

sequence stratigraphic horizons, (Fürsich and Pandey, 2003) demonstrated this by

126

delineating transgressive system tract (Maximum flooding surfaces) in the Jurassic

shell accumulations from Kachchh basin they showed how characteristics features of

concentration at the base of Transgressive System Tract are moderate time averaging

with moderate shorting and have disarticulated shells with preferred convex upward

orientation. Similar feature are shown by High Stand system Tract sediments in their

study except that their shells were largely concentrated in lenses and in pavements

rather than in beds as transgressive lags. Maximum flooding surface concentration are

autochthonous and highly time averaged, having accumulated in during low rate of

sedimentation below the storm wave base. Thus, taphonomic analysis have

significantly demonstrated its usefulness in sequence stratigraphic analysis (e.g.

Meldahl, 1987, 1993; Banerjee and Kidwell, 1991; Kidwell, 1991; Brett and Baire,

1998; Kondo et al. 1998; Fürsich and Pandey, 1999; Hisao and Kondo, 1999; Best

and Kidwell, 2000 a, b; Di Celme et al. 2002; Courville and Collin, 2002; Fürsich and

Pandey, 2003; Cantalamessa et al. 2005; Parras and Casadio, 2005 Fernandez Lopez

and Sha, 2013; Scarponi et al, 2013) .

5.2 Methodology and data collection

Five important stratigraphic horizons within the Paleogene sediments of

Kachchh and Jaisalmer basin were studied for understanding taphonomic process and

paleoecology for integrating with sequence stratigraphy. Various taphonomic

attributes were recorded and microstratigraphic details of each horizon were recorded

to categorize fossiliferous horizons into process linked shell concentration types.

Examinations on shell beds for collecting data were made in the field following

procedure mentioned in (Kidwell and Holand 1991) and in laboratory following the

standard procedures (Kidwell et al. 1986; Kidwell and Holland, 1991). Thickness,

lateral extent, type of contact with overlying and underlying beds and geometry of

127

fossil concentrations were also recorded for the shell accumulations. Based on above

observations, the shell beds of the study area are classified into different types as

recognized in Kidwell (1991). In this chapter author presents taphonomic attributes

from the Paleogene succession of Kachchh and Jaisalmer basin in the background of

overall sediment deposition and highlights taphonomic attributes of the shell

concentrations and examines their mode of occurrence in sequence stratigraphic

framework.

5.3 Description of the studied taphofacies in the Paleogene sediments.

Field parameters for studying skeletal concentrations are based on four

aspects: 1) bioclastic fabric, 2) geometry, 3) internal structure, 4) Nature of shell

concentration. Biofabric: refers to the three dimensional arrangement of the skeletal

elements in the matrix. It includes skeletal orientation, closed packing on

hydrodynamics of the hard part concentration, but may also reflect the rotation and

disarticulation of the elements during compaction (if any). Geometry: The geometry

of a fossil concentration depends upon a number of biologic and physical factors.

These include 1) inherited topography of the depositional surface (e.g., crevice and

burrow fills); 2) the mode of life of the hard part producer (e.g., epibenthic clumps of

gregarious taxa such as oysters and Mussels; 3) activities of the other living organism

(e.g., fecal pellets, gastric residues, shell-lined burrows and shell lags produced

through selective deposition feeding. 4) physical process of hard part concentration

that produce syn genetic topography (e.g. lags produced by migrating ripples,

channels and shoals). Based on the above discussed points, taphofacies are described

in detail.

128

5.3.1 Taphofacies 1 (T-1):

Thetaphofacies is characterized by the presence of low diversity, small sized

bivalves and gastropods that are embedded in mudstone and in core of digenetic

nodules (Figure 5.1; Table 5.1, 5.2, 5.3 and 5.4). Most of the shells are very well size

sorted. Bivalves are preserved in two modes one as articulated with two valves intact

and other only as single valve. 78% of the specimens are dominated by single valve

bivalve specimens. Some of the bivalve such as Yoldia beringiana ranges in size from

(.36 to 1.15 cm) (Figure – 5.1 a). The average size of the gastropods ranges from

(0.66 to 1.1 cm) (Figure- 5.1a & b). The shells occur as dominantly convex-up

positions that are densely packed. The accumulation shows coarsening up trend with

smaller and fragmented specimen occurred at the base of the accumulation and coarse

and larger fragments occurring at the top of the accumulation. The accumulation is

again overlain by mudstone.

Occurrence: This taphofacies is also reported from the lower part of the Neradi

Formation, Kakdi River, 0.5 m from the base of the Section – 2 (Figure – 2.6).

Interpretation: The presence of disarticulated, fragmented, densely packed, small

size gastropods and bivalves in the calcareous mudstone suggests that they were

Fig. 5.1 shows both view of taphofacies -2 in the Nodular limestone band -1, dominant fauna includes Gastropods and Pelecypods in mudstone at Naredi Formation, section - 2.

129

Fig. 5.2 Photograph shows the exppression of taphofacies -2 in the Neradi section. (a) Cardium, Nucula(Nucula) COX (b) Spondylus isp. (C) Graphiya (d) Corbula bicorbula. Coin diameter is 24mm.

deposited as a result of storm conditions. This fact is further supported by the

coarsening upward trend shown by the shell accumulation. Thus, based on the nature

of the diversity, articulation and fragmentation, it appears to be within habitat re-

working on account of high energy-storm conditions. The absence of the borings on

the shells indicates that the shells were quickly buried in the sediments. This

taphofacies is interpreted as storm concentrated event beds.

5.3.2 Taphofacies 2 (T-2):

This taphofacies (Figure 5.2; Table 5.1, 5.2, 5.3 and 5.4) is in the Naredi

formation in Kachchh basin. It consists of numerous bivalve and rare gastropod body

fossils and molds that are preserved in fine to medium grained hard, compact

yellowish colored nodular limestone. The fossils identified include different species

of Corbula (bicorbula) sp, Cardiumsp, Grypheasp Nucula (Nucula) archiaci, and

Spondylus. Sp., Venericardia sp. Nearly 95% of the shells are found in life position

and shows articulations with rare signs of abrasion. Abundance of bioclast is

130

moderate to rare in the studied horizon, and at places appears to be dispersed. The size

of the gastropods ranges from 4.0 to 5.38 cm while bivalves range from 2.08 to 8.30

cm. (Figure – 5.2 a, b, c &d). This taphofacies can be laterally traced for several

meters in the studied area and is also occurs in time equivalent sections in basin.

Occurrence: Naredi Formation, Kakdi river section 4.5 meter form base of the

studied section 2 (Figure –2.6) and 5 meter from the base of the studied section 3

(Figure – 2.7). Fulra Formation, Ghodhatad Section 3 meter from the base of the

section (Figure – 2.13)

Interpretation: The presence of dispersed body fossils along with molds in the life

position and well-articulated specimens indicates that most of the bivalves were

burrowing bivalves adapted to dwell in soft sediment (Table 5.1, 5.2, 5.3 and 5.4).

The occurrence of several specimens of well-preserved Spondylus also suggests the

accumulation took place in the soft ground (Figure-5.2 b). Based on the articulation

and preservation in life position, of bivalves and gastropods shells a winnowing action

along with low rate of sedimentation is envisaged for this facies. Such condition of

well-preserved bivalves in life position commonly occurs in low energy conditions

(Bhonde and Desai, 2011). Hence, calm water and low energy conditions within the

shallow marine environment are interpreted. This taphofacies is interpreted as simple

event concentration of within-habitat reworking.

5.3.3 Taphofacies 3 (T-3):

This facies is characterized by the presence of densely packed bioclast. Based on the

field and laboratory observations, this taphofacies and can be divided into two sub

taphofacies (Figure 5.3, Table 5.1, 5.2, 5.3, 5.4), Taphofacies 3 a (T-3a) and

taphofacies 3 b (T-3b). T-3a is dominantly characterized by densely packed, fragment

and disarticulated medium size, moderately diverse bivalve and gastropod molds.

131

The calcareous shell of the fossils is no longer preserved and bivalve mold show

concave up position. The average size of these molds ranges from (0.5 to 1.5 cm)

while (Fig. 5.3 a). In contrast, T-3b is dominated with large size bivalves and

gastropods that are rich in diversity. The average size ranges from (1 to 2.5 cm). (Fig.

5.3 a&b). In some cases thin shelled bivalve also appears together with thick shell

bivalve. The articulation and fragmentation is less as compared to T-3a and do not

Fig. 5.3 (a) Photograph shows the taphofacies -3a and taphofacies -3b and (b) show the coquina -2 arrow shows presence of Ensis (Razor calm) both the taphofacies are exposed in the Harudi Formation. Harudi Scarp section, KACHCHH basin.

132

have any preferred orientation. However, in field and hand specimen the taphofacies

show gradation from T-3a to T-3b. The shells exposed on the top part of the T-3b

shows borings and encrustation. A second level of shell accumulation, showing

similar character to T-3b, also occurs in the section and is exposed at 1 meter above

the T-3b.

Occurrence: This taphofacies is well developed in Harudi formation exposed in the

Harudi cliff Section (Figure – 2.9 ) T-3 a and b are exposed at 3.5 meter from the base

of the section while second shell accumulation is exposed at 4.6 meter from the base

of the studies section.

Interpretation: the nature of shell accumulation in T-3a indicates moderate energy

conditions with digenetic effect altering the shells. The transition from T-3a to T-3b is

gradational and do not show any evidence of erosion. Thus, indicating complex

process for the deposition of the two sub-facies. T-3b shows large, comparatively less

fragmented shells but having very high faunal diversity. It indicates mixed

assemblages of within-habitat input and exotic shell input. The shell boring in top part

of T-3b indicates hard ground surface that is interpreted to be formed during slight

drop in sea level. Large size and the disarticulate nature of the dis-oriented bioclast in

the T-3b suggests its formation during a storm event. While moderate energy within

habitat re-working is envisaged for T-3a. Such shell accumulations are considered to

be composite shell accumulation with different or overlapping processes. The

taphofacies is interpreted to be vertically stacked composite concentration.

5.3.4 Taphofacies 4 (T-4):

The taphofacies is characterized by occurrence of Nummulites obtusus, a

larger benthic Foraminifera (Figure 5.4; Table, 5.1, 5.2, 5.3, 5.4). The shells are

loosely embedded in the clay and show evidences of abrasion and boring. In case of

133

Fig. 5.4 Photograph shows expression of taphofacies – 4 comprise of N. obtusus extensively exposed in middle part of the Harudi formation KACHCHH basin.

boring nearly 30-40% of the shells are thoroughly bored. Other fossils that co-occur

with this are bivalves. However they do not show any evidence of borings or post

mortem alteration (Figure –2.9). The boring on the shells occurs as shallow pits,

cylindrical holes, paraboloid pits and subspherical cavities indicative of dwelling

structures rather than predation boring.

Occurrence: Harudi formation, 15 meters from the base of the Harudi section

(Figure-2.9)

Interpretation: The presence of extensive boring suggests that the fossils were

exposed after its deposition and there was enough time for the animal to bore the

substrate. Görmus and Nielsen (2006) have analyzed boring on the cretaceous and

tertiary larger foraminifera from the Eocene of Turkey and have suggested that such

134

boring occur in shallow carbonate setting during the initial phase of regression.

However, low rate of sedimentation can also occur in cases when there is sudden

transgression, for example, the Oxfordian Dhosa Oolite bed of the Kachchh (Alberti

et al, 2013). Hence the taphofacies indicates that the rate of sedimentation was

extremely low along with low energy conditions. The taphofacies is indicative of

simple event concentration with low rate of sedimentation and within habitat

reworking.

5.3.5 Taphofacies 5 (T-5):

The taphofacies is characterized by fossil accumulation of echinoid spines

along with bivalves shells placed within the medium grained grey colored calcareous

mudstone (Figure 5.5; table 5.1, 2, 3, 4).In cross section echinoid spines can be seen

jutting from the exposed surface in the cross section(Figure –2.16). The bivalve shells

are thin walled, fragmented and disarticulated and show moderated species diversity.

The echinoid spines do not show any major abrasion or breakage. The bivalves and

spines co-occur together and appear to be mixed. Size of the spines ranges from 2 to 3

cm in length. The shell accumulations occur as pods and smaller size geometry and do

not extend for wider distances.

Occurrence: The taphofacies is well exposed at multiple levels inFulra limestone

Formation, at Walsara waterfall section 500 mt from base of the base of the section.

(Fig. 2.16,)

Interpretation: The presence of echinoids and disarticulate bioclast suggests high

energy condition responsible for the deposition. The overall geometry suggest that

this was local phenomena related to erosion and formation of shallow pits or pods

which were later filled with shell accumulation. The bivalves are dominantly thin

walled and are more susceptible for fragmentation than echinoid spines. This

135

taphofacies indicates its deposition in high energy conditions in shallow marine

environment. The taphofacies indicates simple event concentration with mixing of

within habitat reworking and input of exotic shells.

Fig. 5.5 Photograph shows expression of Echinoids – bivalve taphofacies 5 exposed in Oligocene sediments, Walsara waterfall section KACHCHH basin. (a) Arrangement of Echinoid spines in the mudstone. (1), (2), (3) and (4) shows the enlarge view of the (a)

136

Fig. 5.6 Photograph shows Nummulites Pectene taphofacies - 6 sharing sharp contact with the underlying yellow color mudstone that is rich in thalasonoid in waior section; (b) Nestling observed in the Discocyclina Fulra limestone in the Ratipar section KACHCHH basin.

5.3.6: Taphofacies 6 (T-6):

The taphofacies is characterized by strong preference for hydrodynamic sorting of the

bioclast. The bioclast are either aligned in a preferable direction or nestled (Figure –

5.6 a&b). Sorting and preservation of the bioclast is moderate to very good and no

encrustation can be seen on any of the fossils. Alignment of the bioclast is seen in two

different conditions (a) as a cross stratification (Figure - 3.9) (b) as meniscate and

aligned in burrows. However they areirregularly occurring in the entire Fulra

limestone. Nestling is a common and found in most of the studied section. They are

easily recognized in the cross section. These bioclasts are embedded in the fine

137

grained matrix. The average size of the Bioclast ranges from .5 to 3cm.

Occurrence: Fulra limestone formation, 1meter from base of the studied Ber section

(Fig. 2.10) Fulra limestone formation, 1.5meter from base of the exposed Ratipar

section. Fig. 2.12).

Interpretation: The arrangement and the nature of bioclasts suggest they were

deposited in the high energy environment. Presence of nestling suggests the

deposition of this taphofacies occurred in the high energy conditions. The taphofacies

indicates composite or amalgamated event concentrations.

5.3.7: Taphofacies 7 (T-7):

This taphofacies is characterized by the presence of irregular echinoid along

with Pectene shells. Most of the echinoids belong to one or two genus. The shells of

the echoinoid show moderate abrasion. The average size of the echinoid ranges from

2.5 to 6.5 cm. In contrast the bivalves are dominated by Pectene and show

disarticulation and fragmentation. All of the specimens belong are larger in size and

appears to be adult specimen. The bioclast exposed in the bed is embedded in the off

Fig. 5.7 Photograph shows expression of broken Echinoid taphofacies – 7 exposed in Ber section Maniyara fort formation KACHCHH basin. Coin diameter is 24mm

138

white colored coarse grained compact mudstone (Figure- 5.7). The Pecten or echinoid

does not show any evidence of encrustation or post mortem borings,

Occurrence: Fulra limestone. Ber section 300mt from the base of the section (Figure-

2.22).

Interpretation: The nature of shell accumulation and fossil content along with Lack

of encrustation or boring indicates that the shells were deposited with rapid

sedimentation. Thus it appears to be an event concentration formed in moderate

energy in shallow marine condition with higher rate of sediment and shell burial. A

storm concentration composite event is envisaged for this taphofacies.

5.3.8 Taphofacies 8 (T-8):

The taphofacies is characterized by moderate diversity fossils dominated by

bivalves, gastropods and calcareous tubes of Polychaetes. Most of the calcareous

tubes are cylindrical in nature and appears to be sedentary, comparable to the modern

polychaete family of Sabellidae. Bivalves are dominantly thin shelled, disarticulated,

Fig. 5.8 Photograph shows the expression of Taphofacies - 8 exposed in walsara section and ber section KACHCHH basin. Length of hammer is 230mm and coin diameter is 24mm.

139

disoriented, and fragmented. However the fragments are angular in nature. In

sectional view, the shells are dominantly convex up position. However the polychaete

tubes are well preserved with no abrasion. Nearly 70 % of the measured tubes appear

to be in life position (vertical) (Figure -5.8)

Occurrence: Fulra limestone section, 2.5 meter from base of the exposed walsara

waterfall section. (Figure – 2.16)

Interpretation: Calcareous tube making Polychaetes like Sabellidae are filter feeders

organism (Flauchald and Jumars, 1979) that requires quiet environment. Since the

turbid water with suspended particles may clog their feeding apparatus and therefore

prefer to colonize calm/quiet. Hence occurrence of the calcareous tubes indicates low

energy, clear water conditions. On contrary, broken and fragmented bivalves indicates

high energy storm like conditions. The co-occurrence of such taphonomic signature

indicates composite taphonomic signature or composite shell beds. Polychaetes might

have colonized the high energy deposited shells beds. This taphofacies indicates

simple event concentration of within habitat reworking.

140

Table – 5.1: Show the paleontological features in the studied taphofacies in the Paleogene sediments in Kachchh and Jaisalmer basins.

Taphofacies

Attributes

Tap

hofa

cies

1

Tap

hofa

cies

2

Taphofacies 3

Tap

hofa

cies

4

Tap

hofa

cies

5

Tap

hofa

cies

6

Tap

hofa

cies

7

Tap

hofa

cies

8

T F- 3a TF- 3b

No of Species Few few ~ 30 ~30 One Few Few Few Few

Relative abundance All individual from different species

One individual from one species

All individual from different species

All individual from different species

All individual from one species

All individual from different species

All individual from different

species

All individual from different species

All individual from different species

Taxonomic composition

Bivalves, gastropods

Bivalves Bivalves, gastropods, foraminifera

Bivalves, gastropods, foraminifera

Nummulites obtusus,

Bivalves, Gastropods, Echinoids, Foraminiferas

Echinoides and Pecten dominates

Thin shelled bivalve, polychaete tubes, gastropods

Foraminifers

Ecological Spectrum (Dominant life habbits)

Benthic mixed feeding mode

Benthic infauna, Suspension feeding

Benthic, mixed feeding mode

Benthic, mixed feeding mode

Benthic Benthic, infauna, and epifauna, mixed feeding

Benthic infauna and epifauna, mixed feeding

Benthic infauna, mixed feeding

Benthic

Age Spectrum juveniles Mixed mixed Mixed adults mixed Adults Mixed Adult

Original mineralogy

Aragonite/Calcite

Aragonite Aragonite/Calcite Aragonite/Calcite

Aragonite Aragonite Aragonite Aragonite, Calcite Aragonite, Calcite

Preserved Mineralogy

Recrystallized

Mold Recrystallized Recrystallized

Original Recrystallized Recrystallized Recrystallized

141

Table -5.2: Showing Taphonomic features in the studied taphofacies in the Paleogene sediments of Kachchh and Jaisalmer basin.

Taphofacies

Attributes

Tap

hofa

cies

1

Tap

hofa

cies

2 Taphofacies 3

Tap

hofa

cies

4

Tap

hofa

cies

5

Tap

hofa

cies

6

Tap

hofa

cies

7

Tap

hofa

cies

8

TF-3A TF-3B

Articulation

Dis

articulated but

closely

associated

Disarticulated

and Articulated

Disarticulated

and

disassociated

Disarticulated

and

disassociated

Disarticulated

and

disassociated

Disarticulated

and

disassociated

Disarticulated

and

disassociated

Dis

articulated

but closely

associated

Dis articulated

Size sorting Well sorted Very well

sorted

Moderately

sorted

Poorly sorted Well sorted Poorly sorted Poorly sorted Well sorted Moderately

sorted

Modal size and range in (ø) -2 to -3 -4 to -6 -3 to -4 -3 to -5 -3 to -4 -3 to -4 -4 to -6 -3 to -4 -3 to -4

Shape shorting Sorted Sorted Unsorted Unsorted sorted unsorted Unsorted Sorted unsorted

Fragmentation Some broken All whole Some broken All fragments All whole Some broken Some broken All whole All fragments

Abrasion Abraded Unabraded abraded Abraded Un abraded Abraded Abraded All whole All fragments

Rounding Sub rounded - Angular Angular Angular Sub angular Sub angular - Angular

Biological modification None Minor Minor Minor Extensive-

boring

None None None None

Orientation Mixed In life position All disturbed All disturbed Mixed All disturbed All disturbed All aligned All disturbed

Crosse section High variance In life position High variance High variance High variance High variance High variance Preferred

orientation

High variance

Plan view convex up In life position Partially

Stacked

Stacked Convex up/ Convex down High variance imbricated Convex up

142

Table – 5.3: Shows Sedimentological features observed in taphofacies of the Paleogene sediments of Kachchh and Jaisalmer basin.

Taphofacies

Attributes

Tap

hofa

cies

1

Tap

hofa

cies

2 Taphofacies 3

Tap

hofa

cies

4

Tap

hofa

cies

5

Tap

hofa

ceis

6

Tap

hofa

cies

7

Tap

hofa

cies

8

TF- 3A TF-3B

Type of matrix Mudstone Mudstone Wackestone Wackestone Grainstone Mudstone Packstone Packstone

Mudstone

Hydraulic

equivalence of

matrix

mobile Less mobile mobile mobile More mobile Less mobile Less mobile Same as

shells

Less mobile

Relative

abundance of

shells (%)

55 15 25 25 15 5 5 55 5

Close –

packing of

shells

Densely

packed

matrix

supported

Dispersed

matrix

supported

Densely

packed

matrix

supported

Densely

packed

matrix

supported

Dispersed

bioclast

supported

Loosely

packed matrix

supported ,

Dispersed

Loosely

packed clast

supported

Densely

packed

Bioclast

supported

Loosely

packed

matrix

supported

Associated

sedimentary

structures

Uniform

within

massive

beds

Top of size -

graded bed

Top of size

graded bed

Top of size

graded bed

- Base of size

graded bed

Uniform

with in bed

Uniform with

in bed

Uniform

within beds

143

Table – 5.4 Show the Stratigraphic features observed in the studied taphofacies across the Kachchh and Jaisalmer basin

Taphofacies

Attributes Tap

hofa

cies

1

Tap

hofa

cies

2 Taphofacies 3

Tap

hofa

cies

4

Tap

hofa

cies

5

Tap

hofa

cies

6

Tap

hofa

cies

7

Tap

hofa

cies

8

TF-3A TF-3B

Absolute scale thickness 4.76 cm 10 cm 10cm 15cm - 5cm 50cm - -

Lateral extent Few 100 meters Few Meters >10’s KM >10’s KM 10’s KM < 10’s KM Few 100

Meters Few Meters 10’s Km

Relative Scale Within facies

Within facies

Within facies major

Within facies minor

Within facies minor

Within facies minor

Within facies major Within facies

major Within facies

minor

Geometry Pavement Pavement Pavement Pavement Pavement Pavement Pavement Pavement Pavement Internal complexity

Non homogenous

Non homogenous

Non homogenous

Non homogenous

Non homogenous

Non homogenous

Non homogenous

Non homogenous

Non homogenous

Physical contact (Base Top Lateral)

Laterally, inter

bedded

Inter bedded

Inter bedded

Inter bedded - Inter

bedded

gradational Inter bedded Inter bedded

Position in Sequence

Base of sequence

Top of fining upward sequence

Base of the TST

Base of TST

Part of TST Part of HST

Part of HST Part of HST Part of HST

Associated with significant surface

Flooding surface

Flooding surface

- - - - - - -