Antarctique

Antarctic Offshore

Amundsen Sea

As in others area of the Antarctic offshore, in the Amundsen Sea, the geometry of the Plio-Pleistocene strata, which onlap over tilted sediments, is controlled by the the seal level changes induced by the glacio-eustasy. Remind, sea level changes are controlled by: (i) Glacio-Eustasy, which is controlled by variations in the volume of ocean water and is a major cause of absolute (eustatic) sea level changes ; (ii) Tectono-Eustasy, which is controlled by changes in ocean basin volume ; (iii) Geoidal-Eustasy, which is controlled by the distribution of ocean water caused by gravity field variations and (iv) Steric sea level rise or thermal expansion of the oceans. During the melting ice caps, in response to the load of water added to the ocean basins, the sea level will be depressed, and in response to the removed charge (where the ice caps have melted), the continent will be lifted. Redistribution of material within the Earth is affected by overload. It will further constrain the ocean surface variations (induced by gravity anomalies) and so further water redistributions will be required to attempt to equalize gravitational potential. This continuous retroactive gravitational process between the ice caps, oceans and the mainland is the process that, in the end, determines the signature of the absolute sea level, which is observed everywhere the continent and the ocean meet. Notice that on this manual autotrace, the water depth geometry (continentward progressive increasing of the water depth) is easily explained by the removed charge (isostatic rebound), i.e., the continent is uplift as the ice cap melted.