 | Permo-Triassic Collision, Subduction-Zone Metamorphism, and Tectonic Exhumation Along the East Asian Continental Margin |
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Source: http://www.annualreviews.org/doi/abs/10.1146/annurev.earth.35.031306.140146
Annual Review of Earth and Planetary Sciences
Vol. 35: 73-110 (Volume publication date May 2007)
First published online as a Review in Advance on January 30, 2007
DOI: 10.1146/annurev.earth.35.031306.140146
W.G. Ernst, Tatsuki Tsujimori, Ruth Zhang, and J.G. LiouDepartment of Geological and Environmental Sciences, Stanford University, Stanford, California 94305-2115; email: Ernst@geo.stanford.edu
Convergent plate motion at 320210 Ma generated the Tongbai-Dabie-Sulu (east-central China)-Imjingang-Gyeonggi (central Korea)-Renge-Suo (Southwestern Japan)-Sikhote-Alin orogen along the paleo-Pacific edge of cratonal Asia. This amalgamated belt reflects collision between the Sino-Korean and Yangtze cratons on the SW portion, and accretion of outboard oceanic arcs sialic fragments against the NE margin. Subducted Proterozoic-Paleozoic continental and oceanic crustal complexes underwent high- and ultrahigh-pressure metamorphism at low to moderate temperatures. Tectonic slices of sialic crust episodically disengaged from the downgoing plate and, driven by buoyancy, ascended rapidly to midcrustal levels from depths exceeding 90200 km after continental collision in east-central China plus or minus Korea, and from 3050 km after arrival of far-traveled oceanic terranes in SW Japan and the Russian Far East. On achieving neutral buoyancy and stalling out at 1020 km depth, later doming, gravitational collapse, and erosion exposed parts of the high- and ultrahigh-pressure complexes. This curvilinear orogen has been segmented and offset by major and minor transverse faults. Also, regional backarc spreading opened marginal basins behind the Permo-Triassic convergent suture zone, further disturbing portions oceanward.