腾冲—梁河地区含锡花岗岩序列—单元研究

SERIES AND UNIT RESEARCH ON TIN-BEARING GRANITES OF TENGCHONG-LIANGHE AREA

腾冲-梁河地区的花岗岩类,可划分为3个岩群、8个序列、30个单元。东河岩群、古永岩群、槟榔江岩群分别是晚侏罗-早白垩世、晚白垩世、早第三纪形成的花岗岩序列的组合体。单元是形成时代和岩石特征大体相同的侵入体组合;序列是具有相似岩石特征和同源岩浆演化关系的多个单元组成。区内岩浆活动主要受断裂控制。由于在同一造山期内,不同深度的断裂同时活动或同一断裂带在不同深度内的脉动,导至不同深度源的岩浆流同时上升,从而形成物源不同的若干岩浆序列在时问空间上的聚集(成为岩群)。区内锡(钨)、铅锌等多金属、磁铁矿、稀有和稀土元素、水晶等的成矿均与一定的花岗岩序列一单元有关。以锡为主的成矿多集中在古永岩群中的小龙河序列和槟榔江岩群中的来利山序列,系来自以上地壳长英质组分为主的物源岩浆形成的钾长花岗岩。整个岩浆序列演化最后出现区内主要的一类锡矿床,即锡石云英岩矿床。

The granitoid in Tengchong-Lianghe area is divisible into three rook suites, eight series and 30 units, in which the rock suites of Donghe, Guyo-ng and Binlangjiang are the combined mass of granite series respectively for-med in the Upper Jurassic-Lower Cretaceous, Upper Cretaceous and Lower Tertiary. The term‘unit’refers to the intrusion association about the same in formation ages and rock characteristics, and the‘series’is composed of many units with similar rock charactcristics and evolution relationship of the samc derived magma. The magmatic activities in this area are mainly controlled by fractures. The synchronous activity of faults in different depths or the pulsation of identical fault within different depths in the same orogenic phase resulted in the synchronous uplift of magma flow from different depth derivation, thus forming the accumulation (becoming the rock suite), in time and space, of a number of magmatic series having different substance derivation.The metal-lizations in this area including the polymetal of tin(tungsten), lead-zinc, etc., magnetite, rare and rare earth elements and mountain crystal are all relative to a certain granite series-unit The metallization being largely tin was mostly concentrated on the Xiaolonghe series of Guy ong rock suite and the Lailishan series of Binlangjiang rock suite, belonging to the potash feld-spar granite formed by the felsic magma derived itsself from the upper cru-st. The major tin deposit of cassiterite-quartzite type occurred during the last evolution stage for the whole magma series.