T128 Unravelling Timescales of Magmatism, Metamorphism, and Crustal Evolution II

Monday, 16 October 2023
1:30 PM - 5:30 PM
327

EXHUMATION OF THE HIGH TATRA MOUNTAINS AND IMPLICATIONS FOR THE WESTERN CARPATHIANS, SLOVAKIA

Paper number: T128-12
Program: Technical Sessions
Time: 4:10 PM – 4:25 PM

Authors

Abstract

The Carpathian Mountains form the large collisional orocline stretching from Vienna, Austria to Bucharest, Romania. The Inner Western Carpathians include the High Tatra mountains, which feature the highest elevation peaks. Here we studied the exhumation history of an area east of Gerlachovský štít, the topographically highest point of the High Tatras. Granitoid samples from different elevations were collected and analyzed for apatite (U-Th)/He (n=12; 5-6 aliquots) and zircon (U-Th)/He ages (n=22; 2-4 aliquots). In addition, apatite U-Pb dating by LA-ICP-MS was conducted to complement existing zircon U-Pb dates. The zircon (U-Th)/He ages are scattered with respect to elevation, spatial distribution and range from 47.8 ± 5.6 Ma to 15.5 ± 1.9 Ma. The apatite (U-Th)/He ages show apparent cooling ages from 28.2 ± 4.9 Ma to 9.6 ± 0.6 Ma, with generally younger ages at higher elevation. Apatite U-Pb ages obtained in this study are between 372.74 ± 3.09 Ma and 337.61 ± 2.21 Ma, but generally corresponded with a ~350 Ma crystallization. These ages agree with previously reported zircon dates, indicating a rapid cooling of these granitoids following crystallization. We determined an estimated burial depth in two defined regions using a synthetic grain, multi-thermochronometric HeFTy inverse model. The Velická Dolina region achieved maximum burial from about 35 Ma to 20 Ma at an estimated burial depth between 6.4 – 8.25 km, and samples in the Lomnický štít region achieved a maximum burial from about 40 Ma to 35 Ma, an estimated burial depth of 5.2 - 7.5 km. These ages may have been influenced by lineaments that divide individually exhumed blocks of the High Tatra Mountains. The results of the (U-Th)/He ages provide insight to quantifying and postulating exhumation patterns of overburden experienced during Paleogene accumulation from the middle Eocene through rapid cooling during early and middle-Miocene tectonic unroofing. Furthermore, we suggest final exhumation was induced by transpressive uplift as recently as 10 Ma, evidenced by spatial trends in ages which imply strike-slip stepover faulting. These results outline the earliest tectonic history of the High Tatra Mountains until the onset of most recent exhumation, and impacts our greater understanding of the origin and development of the Western Carpathian mountains.

Geological Society of America Abstracts with Programs. Vol. 55, No. 6

doi: 10.1130/abs/2023AM-393919

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