Alpine geodynamic evolution of passive and active continental margin sequences in the Tauern Window (eastern Alps, Austria, Italy): a review

1998 ◽  
Vol 87 (2) ◽  
pp. 225-242 ◽  
Author(s):  
W. Kurz ◽  
F. Neubauer ◽  
J. Genser ◽  
E. Dachs
Author(s):  
Ulrike Poller ◽  
Wolfgang Todt

New U/Pb results by cathodoluminescence-controlled single zircon dating of rocks from the High Tatra Mountains (Slovakia) constrain ages for the protolith at 2Ga for the granitoids and 3 Ga for the Koncistá migmatite. Concordant single zircon ages date the intrusion of the migmatite precursor at 3567 Ma and the migmatisation at 332 ± 5 Ma. The intrusion of this precursor corresponds with the major granite intrusion in the Western Tatra Mountains. The geodynamic scenario at this time is described as slab detachment of subducted oceanic crust at the active continental margin of Gondwana. The resulting upwelling of asthenospheric mantle brought enough heat for the anatexis of old metasediments and the production of new H- to S-type granites. High Tatra diorites have an intrusion age of 341 ± 5 Ma, constrained by a concordant single zircon age. This age marks the beginning of the Variscan collision of the two convergent continents Laurasia and Gondwana. The intrusion of granites in the High Tatra was confirmed by concordant data at 314 ± 4 Ma, documenting the final stage of the Variscan continent collision.


1980 ◽  
Vol 17 (1) ◽  
pp. 142-155 ◽  
Author(s):  
M. Leblanc ◽  
J. R. Lancelot

U–Pb and Rb–Sr ages performed in the Anti-Atlas (Morocco), especially in Bou Azzer area, demonstrate a Pan-African orogeny (680–570 Ma), along the northern margin of the West African craton (2000 Ma). Geological and geochronological data allow the reconstitution of a coherent succession of events of Pan-African ages. The geodynamic evolution of this domain comprises a stage of oceanic opening (ophiolites) followed with a stage of closure: obduction of the ophiolites on the craton, then subduction under an active continental margin. This segment of the Pan-African belt can be correlated with the other parts of the belt, located on the eastern margin of the West African craton.


2019 ◽  
Vol 157 (4) ◽  
pp. 677-689 ◽  
Author(s):  
Binsong Zheng ◽  
Chuanlong Mou ◽  
Renjie Zhou ◽  
Xiuping Wang ◽  
Zhaohui Xiao ◽  
...  

AbstractPermian–Triassic boundary (PTB) volcanic ash beds are widely distributed in South China and were proposed to have a connection with the PTB mass extinction and the assemblage of Pangea. However, their source and tectonic affinity have been highly debated. We present zircon U–Pb ages, trace-element and Hf isotopic data on three new-found PTB volcanic ash beds in the western Hubei area, South China. Laser ablation inductively coupled plasma mass spectrometry U–Pb dating of zircons yields ages of 252.2 ± 3.6 Ma, 251.6 ± 4.9 Ma and 250.4 ± 2.4 Ma for these three volcanic ash beds. Zircons of age c. 240–270 Ma zircons have negative εHf(t) values (–18.17 to –3.91) and Mesoproterozoic–Palaeoproterozoic two-stage Hf model ages (THf2) (1.33–2.23 Ga). Integrated with other PTB ash beds in South China, zircon trace-element signatures and Hf isotopes indicate that they were likely sourced from intermediate to felsic volcanic centres along the Simao–Indochina convergent continental margin. The Qinling convergent continental margin might be another possible source but needs further investigation. Our data support the model that strong convergent margin volcanism took place around South China during late Permian – Early Triassic time, especially in the Simao–Indochina active continental margin and possibly the Qinling active continental margin. These volcanisms overlap temporally with the PTB biocrisis triggered by the Siberian Large Igneous Province. In addition, our data argue that the South China Craton and the Simao–Indochina block had not been amalgamated with the main body of Pangea by late Permian – Early Triassic time.


2018 ◽  
Vol 112 (1) ◽  
pp. 39-53
Author(s):  
Gerit E. U. Griesmeier ◽  
Ralf Schuster ◽  
Bernhard Grasemann

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