滇西含绿柱石伟晶岩锆石U-Pb年代学及其地质意义

对腾冲-梁河地区含绿柱石伟晶岩进行了锆石LA-ICP-MS U-Pb定年和地球化学分析。结果表明：含绿柱石伟晶岩的形成时代为（48.1±0.8）Ma(MSWD=4.0)，锆石形态特征和微量元素特征显示，伟晶岩锆石受到热液的改造。含绿柱石伟晶岩与55~52 Ma的白云母花岗岩在主量元素、微量元素及稀土元素方面表现出极其相似的特征，为钙碱性系列，过铝质花岗岩，表现出强烈的Eu亏损，δEu为0.074~0.083，相对富集HREE，（La/Yb）_N=1.61~1.92，总体表现出典型的“M”型稀土元素四分组效应。含绿柱石伟晶岩是白云母花岗岩浆高度演化的结果，伟晶岩结晶温度为581 ℃，代表了印度-欧亚板块碰撞导致地壳加厚的构造背景。

Zircon LA-ICPMS U-Pb Geochronology of the Beryl-Bearing Pegmatite and Its Geological Significance,Western Yunnan,Southwest China

Zircon LA-ICP-MS U-Pb dating and geochemical analyses were carried out for the beryl-bearing pegmatite of Tengchong-Lianghe area, western Yunnan. Dating results revealed that the beryl-bearing pegmatite were formed at (48.1±0.8) Ma (MSWD=4.0). Zircon morphology and trace element feature indicate that the zircons suffered from hydrothermal alteration. The beryl-bearing pegmatite shows similar characteristics with respect to major elements, trace elements and rare elements with muscovite granite which formed during 55-52 Ma. They are sub-alkaline series, peraluminous granite with strongly Eu depletion, relatively enriched HREE with （La/Yb）_N=1.61-1.92 and showing typical M-type of REE tetrad effect. The genesis of beryl-bearing pegmatite is related to the evolution of muscovite granitoids and the crystallization temperature of beryl-bearing pegmatite is 581 ℃. It indicates the overthickened crust tectonic setting caused by India-Asia continental collision.