Publication Date:
2018-03-19
Description:
The Dronning Maud Land Mountains in East Antarctica form a key area for the better
understanding of the geodynamic evolution of East Antarctica. Specifically, the integration
of geophysics with geology and geochronology reveals the complex tectonic history of East
Antarctica and its significance for Rodinia and Gondwana reconstructions. The international
GEA-expeditions (2010-12) revealed three major tectonic provinces: a westernmost part with
Kalahari (Africa) affinities and an easternmost part from about 35E with Indo-Antarctic affinities
sandwiched in between these two blocks, is an extensive region with juvenile Neoproterozoic
crust (ca. 990-900 Ma), the Tonian Oceanic Arc Super Terrane (TOAST) that shows very
limited signs of a pre-Neoproterozoic history. We have tested the spatial extent of the TOAST
by a regional moraine study that confirm the lack of older material inland, though latest
Mesoproterozoic juvenile rocks frequently do occur in the glacial drift and probably record a
slightly earlier precursor of the TOAST inland. The TOAST records 150 Ma of almost continuous
tectono-metamorphic reworking at medium- to high-grade metamorphic conditions between ca.
650 to 500 Ma. This long-lasting overprinting history is thought to record protracted accretion of
ocean island arc terranes and the final amalgamation of East Antarctica along the major East
African-Antarctic Orogen. There is no sign of significant metamorphic overprint immediately
after the formation of TOAST. Therefore, these island arcs may have formed independent of,
or peripheral to Rodinia, and may reveal major accretionary tectonics outboard of Rodinia.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Conference
,
notRev
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