Tectonic structure and evolution of East Antarctica in the light of knowledge about supercontinents

Abstract

This paper is based on the study of the new geological, isotopic, and geochemical data that were obtained in the last years on the igneous and metamorphic rocks of East Antarctica, dated from Late Mesoproterozoic to Early Paleozoic. This period of its geological history is believed, based on plate-tectonic paleoreconstructions, to include, first, the origin and breakup of the hypothetical Rodinia Supercontinent and, later, the formation of a new supercontinent, Gondwana. Our review and critical study of extensive foreign literature, as well as the results of our own field and laboratory studies of crystalline rocks from the East Antarctica crystalline basement, suggested a different idea: the supercontinental lithospheric block, including the continents of the Gondwana group, had remained intact throughout the Proterozoic, and perhaps throughout the whole of the Precambrian. Intensity-variable extension pulses, which acted on that primary continental lithosphere, might have caused the origin of some local ocean openings, yet did not result, up to the end of the Mesozoic, in the complete breakup of this sialic megablock with any large-scale spreading development.

Early Precambrian mantle derived rocks in the southern Prince Charles Mountains, East Antarctica: age and isotopic constraints

“…East Antarctica is well known for its high-grade metamorphic rocks -felsic (granitic to trondhjemitic) orthogneisses or paragneisses. These rocks are up to 3800-3900 Ma old as evidenced by zircon U-Pb studies (Harley & Black, 1997) and corresponding Sm-Nd model ages (Grikurov & Mikhalsky, 2002 and references therein). The latter indicate that parts of the East Antarctic crust were derived from the mantle as early as in the Eoarchaean.…”

A continent-wide detailed geological map dataset of Antarctica

“…Alternatively, the ATA_GeoMAP_geological_units attribute TECTPROV provides a different break-down of polygons into more-interpretative tectonic provinces 23,40 . It is just one of many possible interpretations of cratonic blocks and tectonic belts [41][42][43][44][45][46][47] , which tend to be strongly reliant on available geochronology, geophysics, and correlation to neighboring continents. The functionality of GeoMAP and other digital geological data might well be improved if a high-level stratigraphic/structural classification scheme were able to be collectively agreed upon for Antarctic Geology, similar to that developed for New Zealand 48 .…”

“…However, classification of outcrop geology then becomes strongly dependent on this interpretative process and the availability and scale of geophysical data to do so. As a consequence, a plethora of continental-scale subdivisions 23,[40][41][42][43][44][45][46][47] have evolved as rapidly as the available science.…”