India–East Antarctica conjugate margins: rift-shear tectonic setting inferred from gravity and bathymetry data

2001 ◽  
Vol 185 (1-2) ◽  
pp. 225-236 ◽  
Author(s):  
Shyam Chand ◽  
M. Radhakrishna ◽  
C. Subrahmanyam
Keyword(s):  
Tectonic Setting ◽  
East Antarctica ◽  
Conjugate Margins

scholarly journals The Bunger Hills: 60 years of geological and geophysical research

2020 ◽  
Vol 32 (2) ◽  
pp. 85-106 ◽  
Author(s):  
Naomi M. Tucker ◽  
Martin Hand ◽  
Chris Clark
Keyword(s):  
Recent Work ◽  
Present State ◽  
Tectonic Setting ◽  
East Antarctica ◽  
Geophysical Research ◽  
Wilkes Land

AbstractCorrelation of Rodinian and Gondwanan crustal domains relies on a thorough knowledge of those vestiges preserved today. The Bunger Hills hold a critical place in East Antarctica, recording the Mesoproterozoic assembly of Australo-Antarctica in Rodinia and the Neoproterozoic–Cambrian amalgamation of Indo- and Australo-Antarctica in Gondwana. It is situated in a region of disputed overlap between the different components of Rodinia and Gondwana, where there is little consensus on the location of sutures in this region and thus often speculative geological interpretations. The Bunger Hills therefore provide an opportunity to better understand the tectonic setting and palaeogeography during the assembly of these supercontinents. Recent work has confirmed that the Bunger Hills are one of few rare outcrops in Wilkes Land, East Antarctica that can be directly correlated with the broader Musgrave–Albany–Fraser–Wilkes Orogen (MAFWO). Whilst other constituent terranes of the MAFWO have been intensely studied, our geological knowledge of the Bunger Hills was comparatively limited until recently. In light of recent geological and geophysical developments, this contribution serves as an updated and concise standalone reference for the present state of knowledge of the Neoarchean–Cambrian evolution of the Bunger Hills region.

scholarly journals Tectonics of the Southern Ocean passive margins in the Africa – East Antarctica region

2019 ◽  
pp. 25-42
Author(s):  
E. N. Melankholina ◽  
N. M. Sushchevskaya
Keyword(s):  
Southern Ocean ◽  
Upper Jurassic ◽  
East Antarctica ◽  
Significant Feature ◽  
Proximal Margin ◽  
Passive Margins ◽  
Initial Stage ◽  
Gondwana Supercontinent ◽  
African Superplume ◽  
Conjugate Margins

Based on geological and geophysical data for the conjugate margins of Africa – East Antarctica, the peculiarities of preparation of the breakup central Gondwana supercontinent are discussed. When using the historical approach, a significant inheritance of the Middle-Upper Jurassic tectono-magmatic development from the preceding time is shown. The first location of tectono-magmatic activity in zones of weakness on the proximal margin, its subsequent migration to distal margins and further oceanic opening is established. The geochemical features of magmas of the region and their sources are under discussion. Evidence for the decisive influence of the Karoo-Mod plume on the development of magmatism is presented. A significant feature of the plume manifestation is considered: the presence of high-magnesian ferruginous picrites , formed by melting of a pyroxenite source with specific composition, coinciding with the central part of the plume and corresponding to the earliest eruptions. We determined the source of magmatism at the initial stage could have been the substance of a rising plume, and magmas reached the surface through existing fractures without interacting with the lithosphere. In the course of evolution, the admixture of pyroxenites in the source decreased and the melts acquired the features of the melting lithospheric mantle, which was reflected in the isotopic characteristics of the melts with a predominance of the enriched EM II component. The structure and magmatism of the Southern Ocean and South Atlantic are compared. Also discussed the locations of the Mesozoic Karoo-Maud and Tristan plumes, as well as the zones of the subsequent breakup of Gondwana, above the margin of the African superplume, indicating a relationship between surface and deep-seated events, is discussed.

Magmatic evolution and tectonic setting of metabasites from Lützow-Holm Complex, East Antarctica

2008 ◽  
Vol 308 (1) ◽  
pp. 211-233 ◽  
Author(s):  
Yoshimitsu Suda ◽  
Yoshinobu Kawano ◽  
Greg Yaxley ◽  
Hiroshi Korenaga ◽  
Yoshikuni Hiroi
Keyword(s):  
Tectonic Setting ◽  
East Antarctica ◽  
Magmatic Evolution

Crustal architecture of the largest pull-apart basin in East Antarctica unveiled

2020 ◽  
Author(s):  
Laura Crispini ◽  
Fausto Ferraccioli ◽  
Egidio Armadillo ◽  
Andreas Läufer ◽  
Antonia Ruppel
Keyword(s):  
Tectonic Setting ◽  
Field Work ◽  
Strike Slip ◽  
East Antarctica ◽  
Large Igneous Province ◽  
Rift System ◽  
Study Region ◽  
Eastern Margin ◽  
Pull Apart Basin ◽  
Slip Deformation

<p>The West Antarctic Rift System (WARS) is known to have experienced distributed/wide mode extension in the Cretaceous, followed by narrow mode and variably oblique extension/transtension in the Cenozoic, the latter potentially linked to the onset of oceanic seafloor spreading within the Adare Basin (Davey et al., 2016, GRL). However, onshore the extent and impact of Cenozoic extension and transtension within the Transantarctic Mountains sector of East Antarctica is currently much less well-constrained from a geophysical perspective.</p><p>Here we combine aeromagnetic, aerogravity, land-gravity and bedrock topography imaging to help constrain the extent, architecture and kinematics of the largest Cenozoic pull-apart basin recognised so far in East Antarctica, the Rennick Graben (RG).</p><p>Enhanced potential field imaging reveals the extent of a Jurassic tholeiitic Large Igneous Province preserved within the RG and the inherited structural architecture of its basement, including remnants of uplifted ca 530-500 Ma arc basement in the northern Wilson Terrane and a ca 490-460 Ma subglacial thrust fault belt separating the Cenozoic western flank of the RG from the eastern margin of Wilkes Subglacial Basin (WSB).</p><p>The architecture of the RG is best explained in terms of a major composite right-lateral pull-part basin that extends from the Oates Coast to the Southern Cross Mountains block. We propose that Cenozoic strike-slip deformation kinematically connected the RG with both the western edge of the WARS and the eastern margin of the WSB. An earlier phase of left-lateral strike slip deformation is also emerging from recent geological field work in the study region but only relatively subtle offsets in aeromagnetic anomaly patterns are visible in currently available regional datasets.</p><p>We conclude that the RG is part of a wider distributed region of the continental lithosphere in East Antarctica that was deformed in response to an evolving Cenozoic transtensional tectonic setting that may have also affected enigmatic sub-basins such as the Cook Basins in the adjacent WSB region.</p>

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