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The Main Shear Zone in Sør Rondane, East Antarctica: Implications for the late‐Pan‐African tectonic evolution of Dronning Maud Land
Author(s) -
Ruppel Antonia S.,
Läufer Andreas,
Jacobs Joachim,
Elburg Marlina,
Krohne Nicole,
Damaske Detlef,
Lisker Frank
Publication year - 2015
Publication title -
tectonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.465
H-Index - 134
eISSN - 1944-9194
pISSN - 0278-7407
DOI - 10.1002/2014tc003763
Subject(s) - geology , shear zone , tectonics , shear (geology) , paleontology , geomorphology
Structural investigations in western Sør Rondane, eastern Dronning Maud Land (DML), provide new insights into the tectonic evolution of East Antarctica. One of the main structural features is the approximately 120 km long and several hundred meters wide WSW‐ENE trending Main Shear Zone (MSZ). It is characterized by dextral high‐strain ductile deformation under peak amphibolite‐facies conditions. Crosscutting relationships with dated magmatic rocks bracket the activity of the MSZ between late Ediacaran to Cambrian times (circa 560 to 530 Ma). The MSZ separates Pan‐African greenschist‐ to granulite‐facies metamorphic rocks with “East African” affinities in the north from a Rayner‐age early Neoproterozoic gabbro‐tonalite‐trondhjemite‐granodiorite complex with “Indo‐Antarctic” affinities in the south. It is interpreted to represent an important lithotectonic strike‐slip boundary at a position close to the eastern margin of the East African‐Antarctic Orogen (EAAO), which is assumed to be located farther south in the ice‐covered region. Together with the possibly coeval left‐lateral South Orvin Shear Zone in central DML, the MSZ may be related to NE directed lateral escape of the EAAO, whereas the Heimefront Shear Zone and South Kirwanveggen Shear Zone of western DML are part of the south directed branch of this bilateral system.