Gravity aspects from recent Earth gravity model EIGEN 6C4 for geoscience and archaeology in Sahara, Egypt

Abstract

A new method to detect paleolakes via their gravity signal is presented (here with implications for geoscience and archaeology). The gravity aspects or descriptors (gravity anomalies/disturbances, second radial derivatives, strike angles and virtual deformations) were applied. They were computed from the gravity field model EIGEN 6C4 (European Improved Gravity model of the Earth by New techniques). The model consists of the best now available satellite and terrestrial data, including gradiometry from the GOCE (Gravity field and steady-state Ocean Circulation Explorer) satellite mission. EIGEN 6C4 has the ground resolution similar to 10 km. From archaeological sources, the positions of archaeological sites of the Holocene occupations between 8500 and 5300 BCE (8.5-5.3 ky BC) in the Eastern Sahara, Western Desert, Egypt were taken. They were correlated with the features found from the gravity data; the correlation is good, assuming that the sites were mostly at paleolake borders or at rivers. Based on this finding, we suggest position, extent and shape of paleolake(s). We also reconsider the origin of Libyan Desert glass in the Great Sand Sea and support hypothesis about an older impact structure created there, repeatedly filled by water, which might be a part of some of the possible paleolake(s).