AdriaticSea

A L P S

CAR P A T H I A N S

P A N N O N I A N

B A S I N

Bratislava

Zagreb

Belgrade

Danube R

.

Tisza

R.Drava R.

N

mountain belts

0 100 km

DI N

AR

I DE

S

~10 m

Trešnjevica quarry - dikes of various composition (basaltic, andesitic, rhyolitc) penetrating through the granitic mass.

Rupnica geosite with the specific phenomenon of columnar jointing

Gradski Vrhovci quarry - main outcrop of the red granite from volcanic mass of Mt. Požeška Gora.

~10 m

Results

Geotectonic framework

Ext e

r na

l Di n

ar i d

es

Transdanubian Central R

ange

Pre-karst & Bosnian Flysch Unit

Dr i n a- I v an

j i ca

Bükk

Western Vardar

Ophiolitic Unit East

ern

Vard

ar

Ophio

litic

Unit

East-Bosnian and Durm

itor

Thrust Sheet

Jadar

S a v a Z o n e

Kopaonik

Southern Alps

Budapest

Zagreb

Banja Luka

Sarajevo

Belgrade

Dubrovnik

Tisia-Dacia

Adr i a

t i c Sea

Periadriatic LineBalaton Line

Mid-Hungarian Line

A L C A PA

0 100 km

EasternAlps

W. Carpathians

N

Graz

14° E 18° E 20° E

16° 18° 20°

47°

45°

43°

47° N

45° N

43° N100 km

N

Požeška gora

POŽEGA

β - basalt

- rhyolite; -granite

PVM rocks: Vesela village

Pakao Creek

Gradski Vrhovci quarry

Slavonian Mts.

Papuk

N

Trešnjevica quarry

Rupnica geosite

VVM rocks:

Albite rhyolite

Andesite

2 km

VOĆIN

5 km

High-temperature acid magmatic rocks from the Late Cretaceous suture zone

between European plate and Adria microplate (Croatia)

Petra Schneider & Dražen Balen

EGU2020-10088

EGU General Assembly 2020

© Author(s) 2020. This work is distributed under

the Creative Commons Attribution 4.0 License.

quartztrachyte/

latite/

lati−andesite/

andesite/

alkali rhyolite/granite

quartzlatite/

dacite/tonalite

rhyolite/granite

rhyodacite/granodiorite

R1- R2 plot (De la Roche et al. 1980)

1000 2000 30000

500

1000

monzonite

syenite

monzonitemonzo-

diorite

volcanite/plutonite

diorite

R = 4Si - 11(Na+K) - 2(Fe+Ti)1

R =

6C

a +

2M

g +

Al

2

A M

F

Calc−alkaline Series

TholeiiteSeries

50 55 60 65 70 75 80

ferroan

magnesian

SiO2

Fe

Ot

(Fe

Ot+

Mg

O)

50 55 60 65 70 75 80

alkalic

alkali−calcic

calc−alkalic

calcic

SiO2

Na

2O

+K

2O

-Ca

O

0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9

met

alum

inou

s

peraluminous

peralkaline

0

0.2

0.8

0.6

0.4

1

-8

-4

8

4

0

12

1

1.4

2.6

2.2

1.8

3

0.6

ASI

A/N

K

Frost et al. (2001)

Geochemistry

Trešnjevica

Vesela

Pakao

Gradski Vrhovci

Rupnica

Legend:

R1-R2 (Batchelor + Bowden 1985)

R1 = 4Si − 11(Na + K) − 2(Fe + Ti)

R2

= 6

Ca

+ 2

Mg

+ A

l

0 1000 2000 3000 4000

MantleFractionates

Pre−plateCollision

Post−collisionUplift

Late−orogenic

AnorogenicSyn−collision

Post−orogenic

0

1000

2000

Hf

Rb 10

3Ta

Granites from a

collisional tectonic

Withinplate

Volcanicarc

Ocean-ridge

Harris et al. 1986

Microelements including REE show that studied rocks have characteristics of A2-type of post-collisional/post-orogenic acid rocks (EBY 1992; 2011), most common A-type of rocks formed during rifting caused by extension and thinning of continental crust. According to geotectonic classification diagrams, rocks from PVM show geochemical signature of volcanic arc, while VVM shows signature of within plate environment.

Simplified geotectonic map of the Dinaride-Alpine-Pannonian region showing the major structural units after SCHMID et al. (2008) with insets from the Basic geological map, and marked localities of the interest in preliminary research.

Zircon

External zircon morphology seems to be uniform with prevailing J3−J5-type for rhyolites and D-type for granite (after PUPIN, 1980) and with average ratio of 2.2:1. Those types are characteristic for the high-temperature magmas (confirmed with the calculated Zr-saturation temperature of 850−930°C, after WATSON & HARISSON, 1983; GERVASONI et al., 2016) originating from the lower crust or even upper mantle.

Inclusions of hematite, F-apatite and anatase have been detected with Raman spectrometry in zircon from all samples, with the most significant findings of kumdykolite and kokchetavite inclusions detected in samples from Vesela and Gradski Vrhovci. Latter inclusions are metastable phases crystallized from enclosed melt and are indicators of a rapid cooling of the host magma (FERRERO et al., 2016; FERRERO & ROSS, 2018).

600

800

1000

1200

60 65 70 75 80

SiO (wt.%)2

T (

°C)

Zr

T range A-type granitesafter EBY (2011)

Scanning electron photomicrographs of zircon from Rupnica, Vesela and Gradski Vrhovci.

Plain-plarized transmitted-light photo-micrographs of zircon from Rupnica and Trešnjevica showing variety of fluid and mineral inclusions.

Plain-polarized transmitted-light photo-micrograph of zircon from Vesela with mineral inclusion and its Raman spectra showing presence of kumdykolite and kokchetavite. Inclusion size approx. 10 μm in diameter.

Rupnica

Trešnjevica

Rupnica

Vesela

G. Vrhovci

Conclusion

According to the results presented here, acid rocks show rather uniform geochemistry, which speaks in favor of the early ideas of the unique magmatic complex, although today at the surface they are separated by ~35 km in distance. Those rocks,

2althouhg small in volume (covering areas of max 30 km ) show potential to be of great regional importance bearing new information about the evolution in the Late Cretaceous in the area of Sava Zone, a suture zone between Tisia Mega-Unit (European plate) and Adria microplate, which spatially and temporally marks the closure of the Neotethys Ocean.

References:

Batchelor R A. & Bowden P (1985): Petrogenetic interpretation of granitoid rock series using multicationic parameters. Chem. Geol. 48, 43–55.Boynton WV (1984): Geochemistry of the rare earth elements: meteorite studies. In: Henderson P. (Ed.): Rare earth element geochemistry. Elsevier, 63–114.De la Roche H, Leterrier J, Grandclaude P & Marchal M (1980): A classification of volcanic and plutonic rocks using R1R2-diagram and major element analyses – its relationships with current

nomenclature. Chem. Geol. 29, 183–210.Eby GN (1992): Chemical subdivision of the A-type granitoids: petrogenetic and tectonic implications. Geology 20, 641–644.Eby GN (2011): A-type granites: magma sources and their contribution to the growth of the continental crust. 7th Hutton Symposium on Granites and Related Rocks, 50–51.Ferrero S & Ross JA (2018): Micropetrology: Are Inclusions Grains of Truth? J. Petrol. 59, 1671–1700. Ferrero S, Ziemann MA, Angel RJ, O´Brien PJ & Wunder B (2016): Kumdykolite, kokchetavite, and cristobalite crystallized in nanogranites from felsic granulites, Orlica–Snieznik Dome

(Bohemian Massif): not evidence for ultrahigh–pressure conditions. Contrib. Mineral. Petrol. 171, 3. Frost BR, Branes CG, Collins WJ, Arculus RJ, Ellis DJ & Frost CD (2001): A geochemical classification for granitic rocks. J. Petrol. 42, 2033–2048.Gervasoni F, Klemme S, Rocha-Junior ERV & Berndt J (2016): Zircon saturation in silicate melts: a new and improved model for aluminous and alkaline melts. Contrib. Mineral. Petrol. 171, 21.Harris NBW, Pearce JA &Tindle AG (1986): Geochemical characteristics of collision- zone magmatism. In: Coward M P & Ries A C (Eds.): Collision Tectonics. Geol. Soc. Spec. Publ. 19, 67–81.Pamić J (1987): Mladoalpinski alkalijsko-feldspatski graniti (aljaskiti) Požeške gore u Slavoniji (Young-Alpine alkali feldspar granites (alaskites) from Mt. Požeška Gora in Slavonia, northern

Yugoslavia). Geologija 30,183–205.Pamić J & Lanphere M (1991): A-type granites from the collisional area of the northernmost Dinarides and Pannonian Basin. Neues Jahrb. Mineral. Abh. 161, 215–236.Pupin JP (1980): Zircon and granite petrology. Contrib. Mineral. Petrol. 73, 207–220.Schmid SM, Bernoulli D, Fügenschuh B, Matenco L, Schefer S, Schuster R, Tischler M & Ustaszewski K (2008): The Alps–Carpathians–Dinarides connection: a compilation of tectonic units. Swiss

J. Geosci. 101, 139–183.Schneider P, Balen D, Massonne H-J & Opitz J (2019): Cretaceous rift-related magmatism in the suture zone of Adria microplate and European plate (Slavonian Mts., Croatia). In: Ondrejka M &

Fridrichová J (Eds.): 9th Mineralogical-petrological Conference PETROS 2019, Zbornik recenzovanych abstraktov a prispevkov, 50–53.Sun SS & McDonough WF (1989): Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. In: Saunders AD & Norry MJ (Eds.): Magmatism in

ocean basins. Geol. Soc. Spec. Publ. 42, 313–345.Watson EB & Harisson TM.1(983): Zircon saturation revisited: temperature and composition effects in a variety of crustal magma types. Earth Planet. Sci. Lett. 64, 295–304.

The Late Cretaceous magmatic rocks within the southwestern part of the Pannonian Basin basement (Croatia) occur in two areas: Voćin volcanic mass (VVM) at the northwestern part of Mt. Papuk (near town of Voćin) and volcanic mass of Mt. Požeška Gora (PVM). Both volcanic masses consist of basalts and rhyolites, and in lesser extent of pyroclastic material. Granite can be found it the PVM.

Interconnection of this two masses and Late Cretaceous ages have been proposed based on the petrography and mineralogical features of previously studied samples and rather arguable data: K-Ar dating on basalts from VVM (~73−52 Ma; ) and Rb-Sr isochron age on granite and rhyolite from PVM (~72 Ma) (PAMIĆ, 1987; PAMIĆ & LANPHERE, 1991). The age has been recently refined with the zircon LA-ICP-MS age dating (~82 Ma; SCHNEIDER et al., 2019), but the magma source of this bimodal formation, geotectonic position, setting and its regional importance still have not been explained in detail.

Introduction

In order to conduct preliminary research, two localities with acid effusive rocks were sampled from the VVM (Rupnica geosite and Trešnjevica quarry), and three more from PVM (near the village of Vesela, Pakao Creek and the granite from quarry near the village of Gradski Vrhovci).

Samples

Cs Ba U K Ce Pr P Zr Eu Dy YbRb Th Nb La Pb Sr Nd Sm Ti Y Lu

Spider plot - Primitive Mantle (Sun and McDonough 1989)

Sa

mp

le/

Pri

miti

ve M

an

tle

1

0.1

10

1000

100

10000

Spider plot - REE chondrite (Boynton 1984)

Sa

mp

le/

RE

E c

ho

nd

rite

La Pr Pm Eu Tb Ho Tm LuCe Nd Sm Gd Dy Er Yb1

10

1000

100