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.
KeywordsGravity Data Moho Depth Geoid Undulation Acoustic Basement Moho Discontinuity
Unable to display preview. Download preview PDF.
- Anderson J.B. & Bartek L.R. (1992). Cenozoic glacial history of the Ross Sea revealed by the intermediate resolution seismic reflection data combined with drill site information. In the Antarctic paleœnvironment: a perspective on global change. Antarctic Research Series ,56, 231–263.CrossRefGoogle Scholar
- Busetti M., Brancolini G., De Santis L.(1994). Seismic sequence Analysis from the Ross Shelf, Terra Antarctica, Vol. 1, pp. 130–133Google Scholar
- Busetti M., Zayatz I. & Ross Sea Regional Working Group (1994). Distribution of Seismic Units in the Ross Sea, Terra Antarctica, Vol. 1, pp. 345–348Google Scholar
- Cerruti G., Alasia F., Geraiak A., Bozzo E.,Caneva G., Lanza R., Marson I. (1992). The Asolute Gravity Station and the Mt. Melbourne Gravity Network in Terra Nova Bay, North Victoria Land, East Antarctica, Recent Progress in Antarctic Earth Science ,pp. 589, 593, TERRAPUB Tokyo 1992,Y. Yoshida editorGoogle Scholar
- Davey F.J. (1994). Bathymetry and Gravity of the Ross Sea Antarctica, Terra Antarctica, Vol. 1, pp. 357,358Google Scholar
- Gantar C., Zanolla C.(1993). Gravity and Magnetic Exploration in the Ross Sea (Antarctica), Boll Geof. Teor. Appl. Vol XXXV, pp.219,230Google Scholar
- Gantar C.(1993). Ties to Harbour Bases for Drift, Scale and Datum Determination in Antarctic Marine Gravity Profiles, Boll. Geof. Teor. Appl. Vol. XXXV, pp.265,289Google Scholar
- Kleinschmidt G., Buggysch W. & Floettmann T. (1992). Compressional Causes for The Early Paleozoic Ross Orogen -Evidence from Victoria Land and The Shackleton Range, Recent Progress in Antarctic Earth Science ,pp. 227,233, TERRAPUB Tokyo 1992,Y. Yoshida editorGoogle Scholar
- Morelli C., Gantar C., Honkasalo T., McConnell R.K., Tanner J.G., Szabo B.,Uotila U., Whalen C.T. (1974). The International Gravity Standardization Net 1971 (IGSN 1971) I.U.G.G., A.I. G. ,Publ Spec. No 4, Paris, 194 pp.Google Scholar
- ten Brink U.S., Bannister S., Beaoudoin B.C., Stern T.A. (1993). Geophysical Investigation of the Tectonic Boundary Between East and West Antarctica, Science (in press).Google Scholar