Open AccessPalaeomagnetic study of eastern Tibet—deformation of the Three Rivers region
Author(s) -
Otofuji Y.,
Inoue Y.,
Funahara S.,
Murata F.,
Zheng X.
Publication year - 1990
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.1990.tb01754.x
Subject(s) - terrane , geology , clockwise , cretaceous , paleomagnetism , tectonics , paleontology , deformation (meteorology) , red beds , seismology , eurasian plate , mesozoic , rotation (mathematics) , subduction , structural basin , geometry , oceanography , mathematics
SUMMARY A palaeomagnetic study was undertaken for Cretaceous red beds and granitic rocks of three geological provinces (the Lhasa, the Qiangtang and the Sichuan) along a road between Chengdu and Lhasa in eastern Tibet in an attempt to determine aspects of deformation of SE Asia. High‐temperature characteristic directions were isolated from 20 sites. The tilt corrected data from the Qiangtang Terrane at Markam (29.7°N, 98.6°E) exhibit largely clockwise deflected declinations with steep inclinations ( D = 48.2°, I = 49.0°, α 95 = 8.8°), whereas the Lhasa Terrane at Basu (30.1°N, 96.9°E) and the Sichuan province at Ya'an (30.1°N, 103.0°E) have northerly directions with shallow inclinations ( D = ‐3.9°, I = 23.4°, α 95 = 19.2° and D = 2.1°, I = 30.7°, α 95 = 11.3°, respectively). The palaeomagnetic data indicate that the Qiangtang Terrane was subjected to clockwise rotation through 50° with respect to the neighbouring provinces of the Lhasa and Sichuan since the Cretaceous. Tectonic deformation occurred later than the Cretaceous in the eastern part of the Qiangtang Terrane and formed the arcuate shape of the orogenic belt in the Three Rivers region.