Crustal Structure of Prydz Bay at 72°E, East Antarctica


Contact
maria.tsekhmistrenko [ at ] awi.de

Abstract

One-hundred-eighty million years ago the Gondwana super-continent broke apart into the continents of Antarctica, Africa, Australia, India and South America. Their drift created the present-day Indian and South Atlantic Ocean. When tectonic plates move apart, the continental drift causes the continental crust to extend until oceanic crust is created by seafloor spreading. This type of process can be observed in several places around the world, e.g. at the Iberian margin in the Atlantic Ocean. The Enderby Basin, a remote region between Kerguelen and the East Antarctic continental margin, displays similar features of this process. Unfortunately, poor geophysical data exist to describe the crustal structure, due to bad accessibility and rough weather conditions. As a consequence high risks are present to conduct such experiments. Since systematic and detailed magnetic data are not available for this area, the timing and orientation of the breakup between India, Australia and East Antarctic contain large un- certainties. Additionally, existing data display poor quality and resolution. Previous models support the theory that the northward drift of India was accelerated at some point. Magnetic anomaly interpretations led to different kinematic models that predict the initiation of the breakup around 118 Ma ago, 135 Ma or at an even older dispersal time. To support tectonic models and solve the enigma regarding the Gondwana breakup, new datasets of magnetic, gravimetric, seismic reflection and refraction data were acquired during two research cruises in 2007 and 2012. This thesis presents a new tectonic model for the geodynamic evolution of the Enderby Basin after the initial Gondwana breakup based on new seismic, magnetic and gravimetric data. We present a P-wave velocity profile which is based on the first seismic refraction profile acquired in the the area between Kerguelen and East Antarctica. The integrated interpretation of the data agrees with previous models about the dating of the Mac Robertson Anomaly. The breakup in this region can be dated at M9/ ∼ 128 Ma based on the magnetic anomaly data and the velocity model. We confirm theories of an breakup closer to the Cretaceous Normal Superchrone in the Enderby Basin which were under dispute for a long time. The model rejects the existence of an fossil spreading ridge, hence the breakup between India and Antarctica was continuous.



Item Type
Thesis (Master)
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Divisions
Primary Division
Programs
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Peer revision
Not peer-reviewed
Publication Status
Published
Eprint ID
38566
Cite as
Tsekhmistrenko, M. (2015): Crustal Structure of Prydz Bay at 72°E, East Antarctica , Master thesis, University of Bremen, Bremen.


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