EGU22-4488
https://doi.org/10.5194/egusphere-egu22-4488
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Early Carboniferous magmatism and metamorphism in the Schladming Complex, Eastern Alps: Constrain on the subduction of Rheic Ocean

Qianwen Huang1,2,3, Yongjiang Liu1,2, Franz Neubauer3, Johann Genser3, Sihua Yuan3,4, Ruihong Chang3, Qingbin Guan1,2, and Shengyao Yu1,2
Qianwen Huang et al.
  • 1Frontiers Science Center for Deep Ocean Multispheres and Earth System; Key Lab of Submarine Geosciences and Prospecting Techniques, MOE and College of Marine Geosciences,Ocean University of China, Qingdao, China (liuyongjiang@ouc.edu.cn;yushengyao@ouc.edu
  • 2Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology,Qingdao, China(liuyongjiang@ouc.edu.cn;yushengyao@ouc.edu.cn; guanqingbin@ouc.edu.com;huangqw_31@163.com)
  • 3Paris-Lodron-University of Salzburg, Department of Geography and Geology, Salzburg, Austria(franz.neubauer@sbg.ac.at; ruihong.chang@stud.sbg.ac.at；johann.genser@sbg.ac.at; sihua.yuan@sbg.ac.at; qianwen.huang@sbg.ac.at)
  • 4College of Earth Science, Institute of Disaster Prevention, Sanhe, China(yuansihua@126.com)

The Schladming-Seckau system as one part of Middle Austroalpine Unit experienced the Variscan event and overprinted by the Alpine orogeny, which is a key to reveal the tectonic evolution history of Easterrn Alps (Neubauer and Frisch, 1992). Recently, Cambrian-Ordovician magmatism and Permian-Triassic magmatism were reported in the Schladming Complex (Huang et al., 2021), they are related to the subduction of Proto-Tethys Ocean and opening of Meliata back-arc basin, respectively. Here, we present the whole-rock geochemistry, zircon U-Pb and Hf isotopic analysis of paragneiss and granitic rocks in the Schöder Valley to constrain the relationship between Schladming Complex and Variscan orogeny.

The biotite-plagioclase gneiss, hornblende-gneiss, mica-schists formed the main body of the Schladming Complex (Neubauer et al., 2018). The zircon age data of biotite-plagioclase gneiss show the peak age of 603 Ma and 487 Ma with dominated metamorphic age of 355 Ma, indicating the rocks mainly sourced from the Neoproterozoic and Ordovician rocks and suffered the strong Carboniferous metamorphism. Similar to the biotite-plagioclase gneiss, two Ordovician granitic gneisses (485Ma – 483 Ma) also comprise significance metamorphic age of 355 Ma. Their primitive mantle-normalized multiple elements patterns exhibit strong depleted in Nb, Ta, Ti, Zr, and Hf, showing a typical subduction-related features.

Not only the metamorphism shows the Carboniferous subduction event, but also two granites prove the existence of Carboniferous magmatism. These two granites have crystallization age of 353 Ma and 355 Ma, respectively. The zircon εHf(t) scatter between -1.29 and 6.04, suggesting the magma of granite derived from deplete mantle and mixed with the continent materials. Their geochemical data display subduction-related characteristics that depleted in HFSE (eg. Nb, Ta, Ti, Zr, and Hf) and enriched in LILE (eg. Ba, Th, K). The Carboniferous metamorphism and magmatism together showing the subduction of Rheic Ocean before Variscan orogeny in the Eastern Alps.

Acknowledgement: The study is financially supported by NSFC (91755212).

 

References

Huang, Q.W., Liu, Y.J., Genser, J., Neubauer, F., Chang, R.H., Yuan, S.H., Guan, Q.B., Yu, S.Y., 2021. Permian-Triassic A-type and I-type granites in the Schladming Complex, Austroalpine Unit: Constraints on subduction of Paleo-Tethys Ocean in the Eastern Alps, In: Li, S., Santosh, M. (Eds.), The 2021 Annual Convention of the International Association for Gondwana Research (IAGR) and the 18th International Symposium on Gondwana to Asia. Gondwana Research, China, Qingdao, pp. 21-22.

Neubauer, F., Frisch, W., 1992. Pre-Mesozoic geology of the Middle and Upper Austro-Alpine metamorphic basement east of the Tauern Window. 17-36.

Neubauer, F., Genser, J., Heberer, B., Etzel, A., Olive, S., 2018. Field Trip Post‐EX‐1 Transect across the Eastern Alps, XXI International Congress of the Carpathian Balkan Geological Association Salzburg, Austria, pp. 137-222.

How to cite: Huang, Q., Liu, Y., Neubauer, F., Genser, J., Yuan, S., Chang, R., Guan, Q., and Yu, S.: Early Carboniferous magmatism and metamorphism in the Schladming Complex, Eastern Alps: Constrain on the subduction of Rheic Ocean, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-4488, https://doi.org/10.5194/egusphere-egu22-4488, 2022.