滇西北金沙江带蛇绿岩,蛇绿混杂岩形成环境及时代

本文对滇西北金沙江带蛇绿岩及其混杂岩的产状、规模，岩石学及岩石化学特征等进行系统的综合研究，并根据大量的化石资料，将该区蛇绿岩的形成时代厘定为晚石炭世至二叠纪，蛇绿要岩的形成时代厘定为早、中三叠世，论证了本区蛇绿岩产于规模较小的洋盆环境之中，由于金沙江洋盆发育阶段较短暂，不具有隔离冈瓦纳及扬子两大古生物地理区系的作用，因此，金沙江缝合带不能构成古特提斯域的主缝合带。

FORMATION AGE AND ENVIRONMENT OF OPHIOLITE AND OPHIOLITIC MELANGE IN THE JINSHAJIANG BELT, NORTHWESTERN YUNNAN

The authors have made an integrated study on the mode of occurrence, extent, petrology and petrochemistry of ophiolite and ophiolitic melange of the Jinshajiang belt in northwestern Yunnan. According to rich fossil data, the age of the ophiolite in the area has been determined to be Late Carboniferous to Permian, while the age of the ophiolitic melange Early-Middle Triassic. The ophiolite is proved to have been formed in an environment of a small oceanic basin. As the oceanic basin stage of the Jinshajiang belt was relatively short, the belt could not have served as a barrier separating the Gondwana biogeographic province from the Yangtze biogeographic province. Consequently, the Jinshajiang suture zone could not constitute the main suture zone in the Paleotethys domain.