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Evolution of gravity anomalies across collisional mountain belts: Clues to the amount of continental convergence and underthrusting
Author(s) -
Lillie Robert J.
Publication year - 1991
Publication title -
tectonics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.465
H-Index - 134
eISSN - 1944-9194
pISSN - 0278-7407
DOI - 10.1029/91tc00356
Subject(s) - geology , bouguer anomaly , crust , lithosphere , continental crust , continental margin , gravity anomaly , isostasy , collision , paleontology , seismology , oceanic crust , stage (stratigraphy) , geophysics , tectonics , subduction , computer security , oil field , computer science
A series of density models illustrates the gross form of free air and Bouguer gravity anomalies anticipated during ocean basin closure and consequent development of collisional orogens. When compared to gravity anomalies observed across some mountain belts, the hypothetical anomalies provide a clue to the degree of under thrusting of crust associated with one lithospheric plate beneath crust of the opposing plate margin. The results of the study suggest very early stage collision in the Ouachita Mountains of Arkansas and the Sulaiman Range of Pakistan, with thin transitional or oceanic crust still intact on the lower plate. In contrast, the Himalaya of Pakistan represent a much more advanced stage of collision, where continental crust may have underthrust the mountains for 600 km.