A gravity survey of eastern Iran was carried out in autumn 1977 and 1978 as a joint effort of the Geophysical Institutes of the Universities of Hamburg and Tehran. The purpose of this investigation was to establish the gravity field in the form of free-air, Bouguer and isostatic anomalies, and to provide their qualitative and quantitative interpretation by developing two- and three-dimensional density models. By investigating the shape of the compressional fronts between the Arabian and Iranian Plates, it was intended to deduce their style of deformation and better understand the process of continental collision. The Bouguer gravity field starts at the area of the Persian Gulf at a level of -50mgal and obtains -220mgal N of Shiraz beside the Zagros main thrust zone. This can be interpreted as being due to the thickening of crust to 50km in this area. In contrast, the Lut and Great Kavir Depressions are characterized by a relative anomaly, which correlates well the fact that Lut and Great Kavir Depressions have a normal continental crust without any appreciable variation in crustal thickness. The Elburs Ranges represent the characteristic of a 'rootless' mountain in the Bouguer gravity map. The crustal thickening below the Zagros mountains causes a broad regional Bouguer anomaly of -180mgal. Isostatic anomalies, computed assuming Airy compensation, show negative anomaly in the area of the Zagros Main Thrust, and positive anomaly in the Elburs area. The Geoid undulation map of Iran shows a positive deformation in the Zagros area, which is connected with crustal thickening.-from Author
A gravity survey of eastern Iran was carried out in autumn 1977 and 1978 as a joint effort of the Geophysical Institutes of the Universities of Hamburg and Tehran. The purpose of this investigation was to establish the gravity field in the form of free-air, Bouguer and isostatic anomalies, and to provide their qualitative and quantitative interpretation by developing two- and three-dimensional density models. By investigating the shape of the compressional fronts between the Arabian and Iranian Plates, it was intended to deduce their style of deformation and better understand the process of continental collision. The Bouguer gravity field starts at the area of the Persian Gulf at a level of -50mgal and obtains -220mgal N of Shiraz beside the Zagros main thrust zone. This can be interpreted as being due to the thickening of crust to 50km in this area. In contrast, the Lut and Great Kavir Depressions are characterized by a relative anomaly, which correlates well the fact that Lut and Great Kavir Depressions have a normal continental crust without any appreciable variation in crustal thickness. The Elburs Ranges represent the characteristic of a 'rootless' mountain in the Bouguer gravity map. The crustal thickening below the Zagros mountains causes a broad regional Bouguer anomaly of -180mgal. Isostatic anomalies, computed assuming Airy compensation, show negative anomaly in the area of the Zagros Main Thrust, and positive anomaly in the Elburs area. The Geoid undulation map of Iran shows a positive deformation in the Zagros area, which is connected with crustal thickening.-from Author