Sub-ice geology inland of the Transantarctic Mountains in light of new aerogeophysical data

Publication Type  Journal Article
Year of Publication  2004
Authors  Studinger, M.; Bell, R. E.; Buck, W. R.; Karner, G. D.; Blankenship, D. D.
Journal Title  Earth and Planetary Science Letters
Volume  220
Issue  3-4
Pages  391-408
Journal Date  Apr 15
ISBN Number  0012-821X
Accession Number  ISI:000220807900012
Key Words  antarctica; transantarctic mountains; wilkes subglacial basin; aerogeophysics; gravity; magnetics; radar echo sounding; east antarctic craton; victoria-land; magnetic interpretation; airborne gravimetry; gravity-anomalies; west antarctica; analytic signal
Abstract  

The Transantarctic Mountains are a major geologic boundary that bisects the Antarctic continent, separating the low-lying, tectonically active terrains of West Antarctica from the East Antarctic craton. A new comprehensive aerogeophysical data set, extending 1150 km from the Ross Sea into the interior of East Antarctica provides insights into the complex structure inland of the Transantarctic Mountains. Geophysical maps, compiled from 21 000 km of gravity, magnetic and subglacial topography data, outline the boundaries of several geologic and tectonic segments within the survey area. The coherent pattern in magnetic data and mesa topography suggests a subglacial extent of the Transantarctic Mountains 400-500 km inland the last exposed rock outcrops. We estimate the maximum thickness of a potential sediment infill in the Wilkes Subglacial Basin to be less than I km, based on gravity modeling and source depth estimates from magnetic data. The coherent nature of the potential field and topography data, together with the northwest-southeast trends, define the Adventure Subglacial Trench and the Resolution Subglacial Highlands as a tectonic unit. The crustal structure and the strong similarity of the observed gravity with fold-and-thrust belts suggest a compressional scenario for the origin of the Adventure Subglacial Trench and the Resolution Subglacial Highlands. The complexity and apparent structural control of the Wilkes Subglacial Basin raise the issue of what influence pre-existing structures may have played in the formation of the Transantarctic Mountains system. The previous hypothesis of a thermal boundary beneath the mountains is difficult to reconcile with our new gravity data. The apparent difficulties to match our new data with certain key aspects of previous models suggests that a reassessment of the existing uplift models is necessary. We have modeled the prominent gravity anomaly over the Transantarctic Mountains with thicker crust. (C) 2004 Elsevier B.V. All rights reserved.

Notes  

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URL  <Go to ISI>://000220807900012
DOI  Doi 10.1016/S0012-821x(04)00066-4