Episodic construction of the Tatra granitoid intrusion (Central Western Carpathians, Poland/Slovakia): consequences for the geodynamics of Variscan collision and Rheic Ocean closure

Aleksandra Gawęda,Jolanta Burda,Krzysztof Szopa,Urs Klötzli,Jan Golonka

doi:10.1007/s00531-015-1239-2

Abstract

The Tatra granitoid pluton (Central Western Carpathians, Poland/Slovakia) is an example of composite polygenetic intrusion, comprising many magmatic pulses varying compositionally from diorite to granite. The U–Pb LA-MC-ICP-MS zircon dating of successive magma batches indicates the presence of magmatic episodes at 370–368, 365, 360, 355 and 350–340 Ma, all together covering a time span of 30 Ma of magmatic activity. The partial resorption and recycling of former granitoid material (“petrological cannibalism”) was a result of the incremental growth of the pluton and temperature in the range of 750–850 °C. The long-lasting granitoid magmatism was connected to the prolonged subduction of oceanic crust and collision of the Proto-Carpathian Terrane with a volcanic arc and finally with Laurussia, closing the Rheic Ocean. The differences in granitoid composition are the results of different depths of crustal melting. More felsic magmas were generated in the outer zone of the volcanic arc, whilst more mafic magmas were formed in the inner part of the supra-subduction zone. The source rocks of the granitoid magmas covered the compositional range of metapelite–amphibolite and were from both lower and upper crust. The presence of the inherited zircon cores suggests that the collision and granitoid magmatism involved crust of Cadomian consolidation age (c. 530 and 518 Ma) forming the Proto-Carpathian Terrane, crust of Avalonian affinity (462, 426 Ma) and melted metasedimentary rocks of volcanic arc provenance.

Highlights

The formation of many granitoid intrusions is considered to result from the incremental assembly of felsic magmas over different periods of time (e.g. Coleman et al 2004; Glazner et al 2004; Paterson et al 2011), usually with addition of mafic components (Słaby and Martin 2008)
The resulting Upper Devonian–Carboniferous granitoid magmatism and metamorphism, and the tectonic zonation have been described in detail from many Western European localities
The aim of this paper is to investigate the zircon U–Pb ages of the successive episodes of granitoid magma intrusion, including the problem of rejuvenation of older magmatic material during subsequent magmatic pulses

Summary

Introduction

The formation of many granitoid intrusions is considered to result from the incremental assembly of felsic magmas over different periods of time (e.g. Coleman et al 2004; Glazner et al 2004; Paterson et al 2011), usually with addition of mafic components (Słaby and Martin 2008). The formation of many granitoid intrusions is considered to result from the incremental assembly of felsic magmas over different periods of time In the case of large-scale, long-lived shear zones, transporting melts and crystal-melt mushes, plutons can be fed by partial melting of both crustal and mantle sources, in different proportions. The resulting Upper Devonian–Carboniferous granitoid magmatism and metamorphism, and the tectonic zonation have been described in detail from many Western European localities. The core mountains in the Carpathian orogenic belt, being fragments of the Variscan continental crust, were subsequently incorporated into the Alpine units (i.e. Tatricum, Veporicum, Gemericum, Zemplinicum; Ebner et al 2008).

Objectives

Results

Conclusion