| 云南西部古生物地理与大地构造演化 |
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| 引用本文：曹仁关.1986.云南西部古生物地理与大地构造演化[J].地球学报,8(2):37-49. |
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| 中文摘要:根据地层古生物的分布和发育情况,可将云南西部划分为保山—腾冲区、耿马—孟连区和兰坪—普洱区。保山—腾冲区古生代地层特别发育,耿马—孟连区主要为晚古生代地层,兰坪—普洱区和生界分布特别广泛。云南西部构造复杂,中元古代时,两个块体在哀牢山一带形成拼结带。中元古代末,两个块体在昌宁、临沧一带形成拼结带。白垩纪中期,保山—腾冲区所属的印度古陆与冈瓦纳古陆分离且向北漂移;始新世末,与欧亚古陆碰撞合并。 |
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| PALAEOBIOGEOGRAPHY AND TECTONIC EVOLUTION OF WESTERN YUNNAN |
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| Abstract:According to the distribution and development of the strata and fossils, western Yunnan may be divided into the Baoshan-Tengchang, Gengma-Meng-lian and Lanping-Pu'er areas. In the Baoshan-Tengchang area, the Paleozoic stata are particulary well developed; in the Gengma-Menlian area, the late Paleozoic strata dominate; in the Lanping-Pu'er area, the Mesozoic strata are very extensively distributed.The tectonics of western Yunnan are rather complex. During the Middle Proterozoic era, two blocks were welded in the Ailao Mountain belt, extending from Malutang of Xinping and Panzhihua region of Yuanyang in Central South Yunnan, and formed a NW-SE-striking collage. The northeastern side of the collage is a highmedium temperature-low-medinu pressure metamorphic belt, with typical minerals of andalusite, cordierite, kyanite, staurolite and garnet. The southwestern side is a low-medium temperature-high medium pressure one, with typical minerals of glaucophane and stilpnomelane. Besides ophiolitic melange and opiolite suite were found, from which pyroxenite and gabbro Were dated as 910 Ma and 1340 Ma respectively.During the end of the Middle Proterozoic, the two blocks were once again welded along the Changning-Yunxiang-Lincang Menghai belt in southwestern Yunnan, forming a NNW-SSE collage. The southwestern side is a lowmedium temperature-high-medium pressure metamorphic beJt whose typical minerals are glaucophane, barroisite, stilpnomelane and phengite, while the northeastern side is a high-medium temperature-low-medium pressure one characterized by an assembladge of andalusite, staurolite, cordierite, sillimanite and hypersthe-ne. The granites dated as 715, 784 and 789 Ma are intruded the Lancang Group and the Chongshan Group of the upper wall of the collage.In the middle Cretaceous time, the Baoshan-Tengchong region (along the present Western border or wesster Yunnan), which was then a portion of the Indian Oldland, began to separate from the Gondwana land, and drifted northward. At the end of the Eocene, it collided and incorporated with the Eurasian plate. |
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