云南特提斯带保山-腾冲地块早古生代岩浆岩  

Early Paleozoic Magmatism in Baoshan-Tengchong Block of the Tethyan Belt, Yunnan Province

作　　者：陈福坤[1] 李秋立[1] 王秀丽[1] 李向辉[1] 

机构地区：[1]中国科学院地质与地球物理研究所固体同位素地球化学实验室,北京100029

出　　处：《地球学报》2005年第B09期93-93,共1页Acta Geoscientica Sinica

基　　金：本文由国家自然科学基金委员会项目（编号：40372106）资助.

摘　　要：云南滇西地区作为东特提斯构造带的重要组成部分之一，其大地构造格局和对全球特提斯演化意义长期以来是众多研究者的关注热点。滇西特提斯构造带（包括川西南部分）是由多个地块和地块相间的造山带组成，如腾冲地体、保山地体、思茅地体及它们之间的属新特提斯带的高黎贡碰撞带和属古特提斯带的昌宁-孟连缝合带等。经受晚古生代—早中生代古特提斯和中生代—新生代新特提斯造山作用的影响，该地区经历了复杂的变质变形。由于地块内部基底出露局限和多期构造作用的叠加影响，特提斯构造带内的变质基底地体的属性和演化历史难于恢复。Western Yunnan belongs to one of the important branches of eastern Tethyan tectonic belt and therefore bears significance of eastern Tethyan belt. The Tengchong-Baoshan block is considered to be a part of the Sibumasu micro-continent, in which the base- ment of Gandwana affinity is exposed. Two granites sampled from the basement section yield U-Pb zircon ages of about 490 Ma, suggesting an early Paleozoic emplacement. In addition, parts of late Cretaceous granites having crustal origin contain inherited zircon cores giving around 500 Ma ages. Granite lenses of 486 Ma were also found in late Paleozoic melange of the Nan-Uttaradit zone suturing the Siburnasu and Indochina blocks. This early Paleozoic magrnatism found in the Tengchong-Baoshan block and in neighboring areas implies a comparable history of the basements between Southeast Asia and western Tethyan belt in early Paleozoic. For example, the basements outcrop in the Alpine belt and probably in the European Variscides as well, which are also considered as continental blocks rifted from Gondwana prior to or simultaneously with those of Southeast Asia.

关 键 词：特提斯构造带 地块 早古生代 腾冲 保山 云南 岩浆岩 大地构造格局 组成部分 

分 类 号：P618.130.1[天文地球—矿床学] P544.1[天文地球—地质学]