Computation of the Moho Depths from Gravity Data in the Ross Sea (Antarctica)
The shape of the Moho discontinuity in the Ross Sea area has been reconstructed using a synthesis of German and Italian marine gravity data, using also the depth to seismic Moho (Behrendt et al. 1991). The first step in this reconstruction starts with the integration of the Simple Bouguer Map, compiled by the Osservatorio Geofisico Sperimentale (OGS) in 1993 (Gantar et al. 1993), with new data from the most recent cruises. Two-dimensional gravity models have been computed along several lines to create a grid accurate enough to produce a 3-D map of Moho depths. Reflection-seismic data have been used to define the shape of the sedimentary units and the upper part of the basement (acoustic) used in the model. Wide angle seismic (reflection and refraction) measurements of Moho depth have also used to constrain the modeling.
Preliminary results indicate smooth trends in depth of the Moho across the Ross Sea. Moho is shallower beneath the basins and deeper under the basement rises. Moho morphology changes from north to south in the Central Trough across a discontinuity which trends northwest - southeast. We interpret a dextral deplacement of 25 km across the discontinuity. This new data set serves as a base for the computation of the geoid undulations in the Ross Sea area.
KeywordsDepression Cretaceous Subduction Refraction Stratigraphy
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