A new Bouguer gravity anomaly field for the Adriatic Sea and its application for the study of the crustal and upper mantle structure

摘要

The purpose of this paper is the development of a new Bouguer anomaly map for the broader Adriatic Sea area to be used as geo-scientific tool which will answer questions mainly regarding the deep and intermediate depth structure of the Adriatic and its surrounding areas. As a first step, a consistent, high-resolution and accuracy free-air gravity anomaly database is created using all the available terrestrial and satellite altimetry data sources. The least-squares collocation (LSC) method is employed to validate the different gravity data sets through an appropriate covariance analysis and following the remove-compute-restore procedure (RCR) for the detailed study of the gravity spectrum. The finally generated gravity database has a resolution of a 0.0333° (~3.2 km) in both latitude and longitude, while its external and internal accuracy is estimated to about ±5 mGal and ±0.5 mGal, respectively. Based on the derived free-air gravity database a new Bouguer gravity anomaly database is determined at the same resolution for the wider region of the Adriatic Sea. Comparison with existing results confirms the reliability of the new Bouguer map for the study area, mainly due to the combination of both land and sea data. The derived Bouguer anomaly map can support different kind of geophysical investigations of both local and regional structure of the study region. As an example three density models are constructed along selected cross sections extracted from the Bouguer anomaly database, in order to obtain structural information for the crustal-upper mantle structure of the region and draw relevant conclusions. The obtained results show that the Bouguer map can provide important information for the lower-crustal/upper-mantle depth range but also helps to constrain the 2D geometry of the shallow geological units, in very good agreement with the observed surface geology and the current understanding of the geotectonic setting of the area.