late cretaceous supra-subduction magmatism in north kozara ... · n kozara s kozara b u l k e a r t...

0 200 km100

Ad

r i at i c

Se

a

N Kozara:U-Pb Zr

S Kozara:Sm-Nd isochron

Borja: Sm-Ndpooled isochron

Lugovic et al. unpubl.

Konjuh: K-Ar Parg

Lanphere et al. 1975Zlatibor: Sm-Nd isochron

Bazylev et al. 2006

Zlatibor: K-Ar Parg, Amph

Lanphere et al. 1975

Brezovica: K-Ar Ms, Hbl161 - 169

Okrusch et al. 1978

Razbojna: K-Ar Amph182 - 187

Karamata & Popevic unpubl.

c. 84 - 70

Ophiolites, suture zones, oceanic accretionary prisms

Europe-derived unitsDinariccontinental marginTisza unit

East Vardar -TransylvanianSava ZoneDinaric ophiolite belt

age obtained from: age in Ma:mafics

metamorphic sole biostratigraphy

157

81.39

literaturethis studyultramafics

0.51294

0.51298

0.51302

0.51306

0.51310

0.51314

0.51318

0.51322

0.06 0.10 0.14 0.18 0.22 0.26 0.30

147Sm/144Nd

143 N

d/14

4 Nd

Age = 157,9 ± 7.6 MaInitial 143Nd/144Nd =0,512871 ± 8.6e-060

K135 Pl WR CPx

CPx

WR

Pl

S KozaraOl-gabbrosample K135

81.6

81.4

81.2

81.0

0.01264

0.01266

0.01268

0.01270

0.01272

0.01274

0.01276

0.0830 0.0832 0.0834 0.0836 0.0838 0.0840 0.0842

207Pb/235U

206P

b/23

8U

Concordia Age = 81.39 ±0.11 Ma(2 , decay-const. errs ignored)MSWD (of concordance) = 1.6,

Probability (of concordance) = 0.20

data-point error ellipses are 2

N Kozarazircons fromdoleritessample K149

Fig. 6a: U-Pb-concordia diagram of zircons from a dolerite from N Kozara. See Fig. 4 for sample locality.

Fig. 6b: Sm-Nd-isochron plot of an olivine cumulate gabbro from S Kozara. (MSWD 0.0109). The initial 143Nd/144Nd value is 0,512871 ± 9. See Fig. 4 for sample locality.

a. North Kozara

0

2

4

6

8

10

12

14

40 45 50 55 60 65 70

b. South Kozara

Na

O +

KO

[wt.%

]2

2

SiO [wt.%]2

gabbropegmatite gabbro

dolerite felsic dike felsic intrusive

Andesite Dacite

Trachyte

TrachydaciteBenmoreite

Mugearite

Hawaiite

Tephrite

Basalt Bas

altic

and

esite

Bas

anite

Picr

obas

alt

a lkal ine

subalkal ine/ tholei i t ic

subalkal ine/ tholei i t ic

0

2

4

6

8

10

12

14

40 45 50 55 60 65 70 75 80 85

Basalt

massive felsitefelsic dike

pillow basaltmassive basalts

composite dike

doleritegabbro

a iiH wa teMugearite

Benmoreite

Trachyte

Trachydacite

Rhyolite

Dacite

Andesite

Bas

altic

and

esite

Picr

obas

alt

Tephrite

Bas

anite

Phono-tephrite

Tephri-phonolite

Na

O +

KO

[wt.%

]2

2

SiO [wt.%]2

alkal ine

subalkal ine / tholei i t ic

subalkal ine / tholei i t ic

1

10

100

1000

La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er TmYb Lu

gabbropegmatite gabbro

dolerite dike felsic dike syenite

rock

/ ch

ondr

ite

c. South Kozara

10

100

La Ce Pr Nd Sm Eu Gd Tb DyHo Er TmYb Lu

dolerite gabbro

pillow basalt massive basalt

rock

/ ch

ondr

ite

a. North Kozara - mafic rocks

1

10

100

1000

La Ce Pr Nd Sm Eu Gd Tb DyHo Er TmYb Lu

dolerite, comp. dike granophyre, comp. dike

felsic dike massive felsites

b. North Kozara - felsic rocks

rock

/ ch

ondr

ite

MORB

Sunda arc

lesserAntilles

Japan

Marianas, Alëutes,South Sandwich

New Zealand

0.5121

0.5122

0.5123

0.5124

0.5125

0.5126

0.5127

0.5128

0.5129

0.5130

0.5131

0.5132

0.5133

0.702 0.703 0.704 0.705 0.706 0.707 0.708 0.709 0.710 0.711

87Sr/86Sr

143 N

d/14

4 Nd

N KozaraS Kozara

B u l k E a r t hdepletedquadrant

enrichedquadrant

Late Cretaceous supra-subduction magmatism in North Kozara (northern Bosnia and Hercegovina): Implications for the Cretaceous to Paleogene collision between

Europe and the Dinaric margin of the Adriatic plateK. Ustaszewski (1), S.M. Schmid (1), B. Lugović (2), R. Schuster (3), U. Schaltegger (4), B. Fügenschuh (5), A. Kounov (1), D. Bernoulli (1), L. Hottinger (1)

& S. Schefer (1)

contact: Kamil.Ustaszewski@unibas.ch

IntroductionOphiolites are a distinctive feature of the internal Dinarides (Fig. 1). Formed in the Neotethys, they were incorporated into Jurassic mélange (Meliata) or obducted onto the passive margin of the Adriatic plate during the Late Jurassic (Vardar). These ophiolites occupy a structurally high position within the SW-verging nappe stack of the Dinarides. The Dinarides formed in Late Cretaceous to Paleogene times in response to closure of a remnant ocean between Adriatic plate and Europe-derived units. The very first evidence for Late Cretaceous intra-oceanic magmatism in the Dinarides was reported by Karamata et al. (2000).

ResultsThis study provides additional evidence for Late Cretaceous igneous activity between the internal Dinarides and Europe-derived units. In the N Kozara Mountains (Figs. 2, 3), a bimodal igneous succession is thrusted onto the Dinaric ophiolite succession of S Kozara, obducted in the Late Jurassic (Figs. 2, 4, 5). Pelagic limestones, intercalated with pillow lavas, contain Campanian globotruncanids (Fig. 3). This is in agreement with U-Pb ages of zircons from dolerites (Fig. 6). REE concentrations suggest an intra-oceanic island-arc origin of the N Kozara mafic rocks (Fig. 7). The initial isotopic values for 80 Ma are 4.4 to 6.3 for εNd and 0.70346 to 0.70507 for 87Sr/86Sr, respectively. With respect to MORB these values indicate only a very low degree of crustal contamination, again suggesting an intra-oceanic origin (Fig. 8).

ConclusionsOur results document the existence of a Campanian island-arc between the Adriatic plate and Europe-derived units (Fig. 10). Subsequent closure of this oceanic domain occurred during the Maastrichtian to earliest Paleogene (Figs. 3, 5). This Late Cretaceous oceanic domain may represent a remnant of either the Vardar ocean (i.e. Neotethys), or alternatively, of the Alpine Tethys.

GeochemistryGeochronology

Geology

Fig. 4: Geologic-tectonic map of the inselberg of Kozara (MGI Balkan 6 coordinates).

Fig. 1: Major tectonic units of the Alps, Carpathians and Dinarides (after Schmid et al., submit-ted). Arrows depict general structural vergences (compiled from various sources).

Fig. 5: Geological cross-section across Kozara and Prosara.

Fig. 2: Simplified geologic-tectonic map of the study area. Only Paleogene and older contacts are shown, disregarding faults related to Neo-gene Pannonian Basin extension.DOB = Dinaric ophiol-ite belt.E = East-Bosnian-Durmitor unit.

Fig. 3: Interpretative correlation of stratigraphic col-umns in the North Bosnian inselbergs (see Fig. 2) after restoring thrust repetitions. Correlated strati-graphic intervals are marked by black lines. The (Late Oligocene) Motajica granitoid of Fig. 2 is not shown in the corresponding stratigraphic column.

Conclusions

Fig. 11: Compilation of radio-metric ages across the Dinaric ophiolites. Mineral abbrevia-tions: Amph=amphibole, Hbl=hornblende, Ms=muscovite, Parg=pargasite, Zr=zircon.

Fig. 7: REE concentrations normalised over chondrite composition. Chondrite values from Boynton (1984).

Fig. 8: Nd- and Sr-isotopy of selected N and S Kozara mafic rock samples.

Fig. 9: IUGS classification of N and S Kozara igneous rocks. Filled symbols from Lugović et al. 1991.

valle

y of P

rijedo

r

S KozaraSSW NNEN Kozara

Gola P

lanina

876m Ta

tica V

is

383m

Sava r

iver

93m

Prosara198° 018°

Serbulo

vac

499m

+3

+2

+1

0

km abovesea level

-1

-2

-3

-4

-5 -5

+3

+2

+1

0

km abovesea level

-1

-2

-3

-4

0 5 km

Maastrichtian suture

projected dip

gabbros

ultramafics (?)

Ca

mp

an

Mid- to Upper Jurassicophiolitic mélangeDurmitor nappe

radiolarites (Bathon to Tithon)

Upper Paleocenelimestones

Eocene turbiditicsandstones & shales

conglomerates, sandstones(?Maastricht - Upper Paleocene)

lherzolites, serpentinites

Miocene to Quaternary

gabbrosdolerites, sheeteddikes & pillow lavas

rhyolites

pelagic limestones & breccias(Campan - ?Maastricht)

pelagic limestones("scaglia")

Prekarst unit

greenschist faciesmetamorphics

"Senonian

Flysch"

thrust ages

Late Jurassic

J CP J P P

P

C

J

P PaleogeneLate Cretaceous

TurjakTurjak

PrijedorPrijedor

Selbulovac 499mSelbulovac 499m

GornjiPodgradci

GornjiPodgradci

Mrakovica 804mMrakovica 804m

Lisina 978mLisina 978m

Gola Planina 876mGola Planina 876m

6400000 6405000

6405000

6410000

6410000

6415000

6415000

6420000

6420000

6425000

6425000

6430000

6430000

4975

000

4980

000

4985

000

4985

000

4990

000

4990

000

4995

000

4995

000

6400000

4975

000

4980

000

0 1 2 3 4 5 kmGabbros

Ca

mp

an

Mid- to Upper Jurassicophiolitic mélange

radiolarites(Bathon to Tithon)

Triassic olistolitheswithin mélange

Upper Paleocene bioclastic limestones

Eocene turbiditicsandstones

conglomerates, sandstones(Maastr. - Upper Paleocene)

ultramafics, serpentinites

Miocene to Quaternary

Gabbros

Dolerites, basaltspillow lavas

Rhyolites

shallow water limestones(Maastricht)

Upper Paleocenebioclastic limestones

pelagic limestones & breccias(Campan- ?Maastricht)

Pelagic limestones("scaglia")

S N

thrust, presumed

thrust, mappedunconformity

beddingfoliation

compiled

own databeddingbedding,overturned

cros

s se

ctio

n(F

ig. 5

)

radiometr ic ages in Ma81.4

80158

U-Pb zirconK-Ar WR

Sm-Nd isochron

80

81.4

158

sheeted dike chilledmargins

bedding: 6 dataslip lineations: 2 data

4 data

mountain peak

town / village

creek

300m

~150

0-20

00m

~150

0-20

00m

? 60

0 - 7

00m

150-

200m

150m

150m

>600

m

~250

m15

0m75

0m

500m

400m

560m

500m

0

S KozaraN Kozara &S Prosara

Motajica

N Prosara

S N

rudistsgraded bedding

unconformitythrust

planktonic foraminiferalarger foraminiferaalgae

Cam

pan

Jura

ssic

Maa

stric

ht -

Low

er P

aleo

cene

Upp

er P

aleo

cene

Up

pe

r P

ale

oce

ne

Eo

ce

ne

Eo

ce

ne

?

Ca

mp

an

?

Ma

as

tr

ic

ht

-

P

al

eo

ce

ne

? C

am

pa

n?

S

an

to

n

an

d

ol

de

r?

M

aa

st

ri

ch

t

-

Pa

le

oc

en

e

Alveolina primaevaDistichoplax biserialis

Orbitoides sp.Lepidorbitoides sp.

Discocyclina seunesi

granitoid, rhyolite, felsic dikemarly limestone

marlsandy limestone

limestone

pelite, shale sandstone, arcose

ophiolitic mélange

prasinite

doleritic sheeted dikes

mica schist

amphibolite

phyllite

marble

gabbro

pillow lavas

conglomerates

metasandstone /-conglomerate

metarhyolite

Globigerins

Campan

Distichoplax biserialis

Contusotruncanapatelliformis

GlobotruncanidsOrbitoides media

Globotruncanids

?

Not metamorphosed

Greenschist toamphibolite facies

Gabbros, dolerites, basaltsN-Kozara

Upper Jurassicophiolitic mélange(Permo)-Triassicto Late Jurassic

Upp

er C

reta

ceou

sto

Pal

eoce

ne

Paleogene granitoids

Upper Paleocene toMid Eocene

(Permo)-Triassic toJurassic cover

Maastrichtian to Paleocenepost-tectonic cover

Anchi- to epizonalmetamorphosed

Mafic and ultramafic rocksS-Kozara

Upper Cretaceousbimodal volcanics

Miocene to Quaternary

Cretaceous S-type granitoids

Cretaceous HT metamorphics

Cretaceous-age migmatite

Paleozoic undifferentiated(metamorphics and cover) P

apuk

-P

sunj

Ko

za

ra

Mos

lava

cka

gora

Pro

sara

, Mot

ajic

a&

Poz

eska

gor

a

boreholes thrust, known thrust, presumed

0 10 205 kmD O BD O BP r e -K a r s tP r e -K a r s t

Prosara

Kozara

Prosara

Kozara

Fig. 4

cross section trace(Fig. 5)

P a p u k

T i s z a

S a v aZ o n eS a v aZ o n e

Pozeskagora

Moslavackagora

Moslavackagora

Motajica

PsunjPsunj

Sava

Una

Dráva

Vrba

s

EEN KozaraS Kozara

Munich

Verona

Kraków

Beograd

Bucharest

Sofia

Sarajevo

Zagreb

Vienna

16°

Ophiolites, suture zones, oceanic accretionary prisms

Europe-derived units

Adria derived far-travelled nappes:Alps & West Carpathians

Dinaric continental margin,including Bükk Mts. (B)

undeformedAdriatic plate

important faults

general structural vergenceundeformedEuropean foreland

external foredeep

Miocene thrust belt

"Tisza" unit with mixedEuropean and Adriatic affinities

B

Adr

ia d

eriv

edth

rust

she

ets

Southern Alps

EVSava

DOB

EV ... East Vardar

DOB ... Dinaric ophiolite belt

Fig. 2Fig. 2

BlackSea

(3) Geologische BundesanstaltNeulinggasse 38A-1030 Wien

(2) Rudarsko-Geološko Naftni FakultetPierottijeva 6HR-10000 Zagreb

(5) Institute for Geology and PaleontologyInnsbruck UniversityInnrain 52fA-6020 Innsbruck

(1) Geological-Paleontological InstituteBasel UniversityBernoullistr. 32CH-4056 Basel

(4) Départment de MinéralogieRue de Maraîchaire 13CH-1205 Genève