Geochronology and petrogenesis of granitoid rocks from the Goryczkowa Unit, Tatra Mountains (Central Western Carpathians)

Abstract

Abstract:The geochemical characteristics as well as the LA-MC-ICP-MS U-Pb zircon age relationship between two granitoid suites found in the Goryczkowa crystalline core in the Western Tatra Mountains were studied. The petrological investigations indicate that both granitoid suites were emplaced at medium crustal level, in a VAG (volcanic arc granites) tectonic setting. However, these suites differ in source material melted and represent two different magmatic stages: suite 1 represents a high temperature, oxidized, pre-plate collision intrusion, emplaced at ca. 371 Ma while suite 2 is late orogenic/anatectic magma, which intruded at ca. 350 Ma. These data are consistent with a period of intensive magmatic activity in the Tatra Mountain crystalline basement. The emplacement of granitoids postdates the LP-HT regional metamorphism/partial melting at ca. 387 Ma and at 433-410 Ma, imprinted in the inherited zircon cores.

LA-ICP-MS U-Pb dating and REE patterns of apatite from the Tatra Mountains, Poland as a monitor of the regional tectonomagmatic activity

“…The Goryczkowa granite, which crops out in the crystalline cores of the Alpine nappes (Jurewicz 2006 ; Fig. 1b), is comprised of granodioritediorite, and was dated at c. 371 Ma and was followed by the intrusion of K-feldspar-rich leucogranite dated at c. 350 Ma by the LA-ICPMS U-Pb method on zircons (Burda et al, 2013b).…”

“…All these granitoid pulses show geochemical and isotopic signatures suggesting that the granitoid melts were produced by melting of a heterogeneous package of metasedimentary rocks during subduction of oceanic crust under the continental wedge and interaction with mantle derived melts (Broska and Uher, 2001;Gawęda, 2009;Burda et al, 2011Burda et al, , 2013aBurda et al, , 2013b.…”

“…For this study we used magmatic rock samples, that were previously dated by the LA-MC-ICP-MS zircon UPb method (Burda et al, 2011(Burda et al, , 2013a(Burda et al, , 2013b and one sample of an apatite-rich cumulate (Szopa et al, 2013). Petrographical analyses of thin sections were undertaken to check the apatite content and its morphological varieties.…”

“…2) Porphyritic to equigranular medium-grained Goryczkowa-type diorite -granodiorite (Fig. 2b) that was dated at 371 ± 6 Ma (Burda et al, 2013b). Accessory minerals are represented by zircon, apatite, zoned allanite and titanite.…”

“…1b). All three samples have yielded different LA-ICP-MS U-Pb zircon ages (337 ± 6 Ma, 371 ± 6 Ma and 368 ± 8 Ma adequately) and represented genetically different magmatic pulses within a polygenetic layered intrusion (Burda et al, 2013a(Burda et al, , 2013b.…”