摘要
区分出中国西南晚古生代以来的两组地体。一组由冈玛错、拉萨、萨迦、腾冲和保山诸地体构成,其共同特点是拥有冈瓦纳相石炭-二叠纪冰筏含砾碎屑岩建造和冷水动物群。另一组包括昌宁-孟连、双江-澜沧、昌都和巴颜喀拉诸地体,以具有华夏植物群和太平洋型筵类的扬子型上古生界为特色。以此为依据,确认两组地体之间的龙木错-双湖-丁青-北澜沧江-柯街-孟定缝合带为冈瓦纳古陆与太平洋古陆在中国西南的分界。根据沉积建造和亚洲侏罗-白垩纪非海相地方性双壳类依次向西南迁移,讨论了该缝合带及分界线西南的一些地体的缝合时代。早侏罗世初,拉萨复合地体中的聂荣一索县地体和保山地体首先与亚洲大陆缝合;早白垩世(Neocomian)末,冈玛错、拉萨和腾冲地体同亚洲大陆碰撞。
Two terranes since the Late Palaeozoic can be distinguished in southwestern China. One is characterised by the Permo-Carboniferous ice-rafted marine gravel-bearing clastic formation and the cold-water fauna of the Gondwana facies, including the Gangmar Co, Lhasa, Sa'gya, Tengchong and Baoshan terranes and the other is marked by the Upper Palaeozoic of the Yangtze type with the Cathaysian flora and the Pacifica-type fusulinaceans, containing the Changning-Menglian, Shuangjiang-Lancang, Qamdo and Bayan Har terranes. The Lungmu Co-Shuanghu-Dngqn-North Lancang River-Kejie-Mengding suture zone between the two groups of terranes is the boundary between Gondwana and Pacifica in southwestern China. On the grounds of the sedimentary formation and successive southwestward migration of the Asian non-marine Jurassic-Cretaceous endemic bivalves, the ages of the suture and some terranes to the southwest of the suture zone are discussed. The Baoshan Terrane and the Nyainrong-Sog Terrane in the Lhasa Compound Terrane was firstly pieced together with the Asian continent in the early Early Jurassic because the first suite of the well-known Mesozoic nonmarine red beds of southwestern China, the lower Lower Jurassic red bed, appeared on both sides of the suture and the Asian non-marine endemic bivalves migrated southwestwards and surpassed the suture. The Zanghei (northern Tibet)-Dianxi (western Yunnan) Microplate, including the Gangmar Co, Lhasa and Tengchong terranes collided with the Asian continent at the end of the Neocomian so that the special endemic trigonioidaceans (non-marine bivalves) of the Asian palaeocontinent surpassed the Bangong Co-Grz-Dongqiao suture. Terranes split from the same major block or plate having a common affinity are known as homogenetic terranes. Terranes split from different major blocks or plates are called heterogenetic terranes. A boundary between the homogenetic terranes is called the homogenetic terrane suture. A boundary between the heterogenetic terranes is relatively defined as the heterogenetic terranes suture.
出处
《地质学报》
EI
CAS
CSCD
北大核心
1990年第3期257-263,共7页
Acta Geologica Sinica
