Abstract
3-D gravity inversion and rift stretching models are used in the Song Hong basin to determine the general configuration of the upper mantle and the mechanism for its formation in the region. The basin approximately 200 km wide by 600 km in length, contains up to 14 km of sediments. The Bouguer gravity field over the basin is relatively flat varying from 0 to-35 mgal, suggesting high density material at the base of the crust. The 3-D inversion was implemented converting modified Bouguer gravity anomalies and using Cordell-Henderson gravity inversion method. Several rift stretching models were calculated using basement depths based on seismic studies and drill holes. The results of gravity modeling suggest that the Song Hong basin is a passive rift in which the failure of lithosphere is due to tension stress which introduces asthenospheric materials to the base of the crust. The tension responsible for the rifting is most probably linked to the collision between the Indian and Eurasia lithospheric plate. In addition, the amount of rotation between Indochina and South China block, which is believed to be associated with the origin of the basin, is calculated from gravity inversion and non-uniform stretching models to be 14.4 and 16.2, respectively.
Nguyen, Vu Giang (1996). Gravity modeling of the Song Hong basin: an insight into its crustal structure and implication for the formation of the basin. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1996 -THESIS -N48.