NUMERICAL MODELLING OF THE AUSTRALIA –ANTARCTICA CONJUGATE MARGINS USING THE GALO SYSTEM: PART 2.
THERMAL AND MATURATION HISTORY OF THE MAWSON SEA BASIN, EAST ANTARCTICA
Y.I. Galushkin1*, G.L. Leitchenkov2, E.P. Dubinin3
1 Lomonosov Moscow State University, Earth Sciences Museum, ul. Leninskie Gory 1, Moscow 119991, Russian Federation.
2 Gramberg VNII Oceanologia, Saint Petersburg; Saint Petersburg State University, Institute of Earth Sciences.
3 Lomonosov Moscow State University, Earth Sciences Museum.
* Corresponding author: email@example.com
Key words: Antarctica, passive margin, Mawson Sea Basin, basin modelling, tectonic subsidence, lithosphere stretching, vitrinite reflectance, heavy oil, light oil.
The thermal evolution of the Mawson Sea Basin, offshore East Antarctic, was modelled using the GALO basin modelling programme. As there exist no deep temperature or vitrinite reflectance data for the Mawson Sea Basin, the simulation was based on a limited non-thermal database. This includes the present-day sedimentary section along a multichannel seismic profile which crosses the western part of the Mawson Sea along with geophysical assessments of the depth of the Moho. An analysis of the variations in tectonic subsidence was used to estimate the duration and magnitude of thermal activation or stretching of the lithosphere. This analysis suggested that a proportion of the lithospheric stretching took place before the start of synrift sediment deposition at about 160 Ma (Late Jurassic). This pre-sedimentation lithospheric stretching has been ignored in previous studies, resulting in significant underestimation of the total stretching which has occurred. The analysis also suggests that the thermal maturity of Lower Jurassic potential source rocks along the profile may reach and even exceed the onset of the oil generation window, whereas source rocks in less deeply buried parts of the profile are less mature. In general, the results of the modelling indicate that the Mawson Sea Basin is a promising area for future oil and gas exploration.
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