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Ref ID: 28384
Ref Type: Journal Article
Authors: Yang, Kaihui
Mo, Xuanxue
Zhu, Qinwen
Title: Tectono-volcanic belts and late Paleozoic-early Mesozoic evolution of southwestern Yunnan, China
Date: 1994
Source: Journal of Southeast Asian Earth Sciences
DOI: 10.1016/0743-9547(94)90024-8
Abstract: Distinct late Paleozoic-early Mesozoic tectono-volcanic belts (i.e. Baoshan-Zengkang, Changning-Menglian, Lincang-Jinghong and the Lancangjiang belts) in southwestern Yunnan may represent a paleo-convergent margin of the eastern Baoshan-Shan-Thai terrane. The Baoshan-Zengkang belt to the north of the terrane is typified by the occurrence of continental basalts within an Upper Carboniferous sequence, representing a short period of intra-cratonic rifting. East of this belt, the Changning-Menglian belt is characterized by the alkalic basalts of intra-continental affinities with less amounts of MORB-like basalts, and is possibly correlated with the Chiang Mai belt in northern Thailand, indicating a Permo-Carboniferous continental extensional zone behind a volcanic arc. The volcanic arc at the eastern margin of the terrane is defined by the Lincang-Jinghong belt which is composed of low-potassium tholeiitic, calcalkalic and shoshonitic associations of mostly Permo-Triassic ages, and is juxtaposed with Indosinian metamorphic units and granitoid batholiths. It may be correlated with the Lampang volcanic belt in Thailand, suggesting westward subduction of a Tethyan oceanic crust (i.e. the Lancangjiang ocean) as represented by the Lancangjiang suture zone. This suture zone, lying between the Baoshan-Shan-Thai and the Changdu-Simao-Indochina terranes, is expressed by dismembered ophiolitic suites in western Yunnan, correlatable with the Nan River suture zone in Thailand. Late Paleozoic-early Mesozoic geological evolution of the area may include the spreading and subduction of the Lancangjiang ocean floor, continental extension possibly resulting from the migrating of a spreading center to the margin of the Baoshan-Shan-Thai terrane, and finally the collision of this terrane with the Changdu-Simao-Indochina terrane.
Date Created: 2/22/2012
Volume: 10
Page Start: 245
Page End: 262