Gravity analysis of the offset between crustal structure and topography in the Liupan Shan, northeast Tibetan Plateau

Abstract

Dense gravity/GPS measurements collected around the southwest margin of the Ordos Block in 2014 and 2017 were used to obtain three gravity anomaly profiles across the Liupan Shan Mountains. The Liupan Shan is located in a Bouguer gravity anomaly (BGA) transitional zone; however, low BGAs to the west do not correspond to the topography of the Liupan Shan in that region, with a maximum offset of approximately 34 km. This offset is also found in inverted crustal density structures whereby the interface between the upper and lower crust is notably concave to the west of the Liupan Shan. Flexural analysis indicates that the effective elastic thickness is 5 km and the uplift is caused by oblique subduction of surface materials. According to this uplift mechanism, the offset suggests that Liupan Shan migrated eastward following partial isostatic compensation. Therefore, we suggest that Liupan Shan has experienced an uplift-compensation-uplift tectonic process.

The Comparative of Morphological and Gravity Anomaly Lineaments in West Progo Mountains, Indonesia The Comparative of Morphological and Gravity Anomaly Lineaments in West Progo Mountains, Indonesia

“…Where Δg x, y, z# is topographic gravity anomaly value, ρ α, β, h# is the distribution of density contrast in the mass point plane h z#, z is the vertical axis that reflects the distance between topography and the reference Spheroid in a positive direction to the center of the earth, and h is the depth of the equivalent source of point mass measured from the reference Spheroid. The gravity method is used to identify geological sub-surface structures, including gravity anomaly to determine the faults depth and direction of the structures in the sub-surface [7], gravity anomaly to determine the control structure of the plateau [8], gravity to determine uplift and tectonic evolution [9].…”