EGU21-8373, updated on 04 Mar 2021
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Cambrian-Ordovician evolution of Eastern Alps: New evidences constrain from magmatic rocks in the Schladming Complex (Austroalpine unit)

Qianwen Huang1,2, Yongjiang Liu1,2, Johann Genser3, Franz Neubauer3, Sihua Yuan3,4, Shengyao Yu1,2, Manfred Bernroider3, Qingbin Guan1,2, Jin Wei5, and Ruihong Chang3
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 (; yushengyao@ouc.
  • 2Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao , China
  • 3Paris-Lodron-University of Salzburg, Department of Geography and Geology, Geology Division, Hellbrunnerstraße 34, 5020 Salzburg, Austria (;;;;ruihong.
  • 4College of Earth Science, Institute of Disaster Prevention, Hebei Province, China (
  • 5College of Earth Sciences, Jilin University, Changchun, China (

The pre-Mesozoic basements in the Eastern Alps overprinted by the Variscan and alpine metamorphism (Neubauer and Frisch, 1993), which still remained the pre-Variscan tectonic evolution evidences. Many of these basements left away from their lithospheric roots due to large-scale tectonic activities (von Raumer et al., 2001), whereas their origin and tectonic history can be recorded by detailed geochemistry and geochronology. Here we present a study on the Schladming Complex, one part of Silvretta-Seckau nappe system in Austroalpine Unit, that located in the northern part of Alps to discuss their ages, origin, and tectonic relationship with the Proto-Tethys Ocean.

The Schladming Complex basement mainly comprises biotite-plagioclase gneiss, hornblende-gneiss, mica-schists, together with some amphibolites, orthogneisses, paragneisses, metagabbro and migmatites, which covered by sequence of metasedimentary (Slapansky and Frank, 1987). It underwent the medium- to high-grade metamorphism during the Variscan event and is overprinted by the greenschist facies metamorphism during the Alpine orogeny (Slapansky and Frank, 1987).

Granodioritic gneisses (539~538 Ma) and fine-grained amphibolite (531±2 Ma) in the basement represent a bimodal magmatism. Geochemical data show that the granodioritic gneisses belong to A2-type granite and originated from the lower crust, while the fine-grained amphibolites have an E-MORB affinity and the magma origined from the lithospheric mantle and contaminated by the arc-related materials. The data implies that the Schladming Complex formed in a back-arc rift tectonic setting in the Early Cambrian.

A medium-grained amphibolite gives an age of 495±5 Ma, exhibits ocean island basalt-like geochemical features and zircons positive εHf(t) values (+5.3~+10.9) indicating that the medium-grained amphibolite derived from a depleted mantle source. The monzonite granitic gneiss and plagioclase gneiss yields ages of 464±4 Ma for and 487±3 Ma, respectively. The monzonite granitic gneiss derived from the mixing of melts derived from pelitic and metaluminous rocks. The protolith of plagioclase gneiss is aplite, which has positive εHf(t) values of +5.9~+7.9, indicating it derived from the lower crust sources. The monzonite granitic gneiss and plagioclase gneiss exhibit S-type and I-type geochemical features, respectively. They are geochemically similar to the volcanic arc granite.

In summary, our data presents record of the Cambrian to Ordovician magmatism in the Schladming Complex, which provided new evidence of tectonic evolution history between Proto-Tethys and Gondwana. According to the data, we proposed that a series of rift developed in the northern margin of Gondwana during 540-530 Ma, the rifts continually expanded into a back-arc ocean in ~490 Ma and was closed around 460 Ma with S-type granitic magma intruded.


Neubauer, F., Frisch, W. 1993. The Austroalpine metamorphic basement east of the Tauern window.  In: Raumer, J. von & Neubauer, F. (eds.): Pre-Mesozoic Geology in the Alps. Berlin (Springer), pp. 515–536.

von Raumer, J., Stampfli, G., Borel, G., Bussy, F., 2001. Organization of pre-Variscan basement areas at the north-Gondwanan margin. International Journal of Earth Sciences 91, 35-52.

Slapansky, P., Frank, W. 1987. Structural evolution and geochronology of the northern margin of the Austroalpine in the northwestern Schladming crystalline (NE Tadstädter Tauern). In: Flügel, H. W. & Faupl, P. (eds.), Geodynamics of the Eastern Alps, pp. 244-262.

How to cite: Huang, Q., Liu, Y., Genser, J., Neubauer, F., Yuan, S., Yu, S., Bernroider, M., Guan, Q., Wei, J., and Chang, R.: Cambrian-Ordovician evolution of Eastern Alps: New evidences constrain from magmatic rocks in the Schladming Complex (Austroalpine unit), EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-8373,, 2021.

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