内蒙古固阳西部地区太古宙变质杂岩中膝折带及其与金矿关系

KINK BANDS AND THEIR RELATION TO GOLD ORE DEPOSIT IN ARCHEAN METAMORPHIC COMPLEX IN THE WESTERN GUYANG AREA, INNER MONGOLIA

内蒙古固阳西部地区“东五分子群”“花岗岩—绿岩地体”在晚太古宙—早元古宙阶段,发生了四期变形。膝折作用属于第四期变形。区内的膝折作用主要发育在叶理化的岩石和糜棱岩中。它的类型有单斜膝折和共轭膝折。单斜膝折和不对称共轭膝折的形成是由于最大压缩应力方向斜交层(或叶理),夹角呈30°左右;对称共轭膝折的形成是由于最大压缩应力方向平行于层(或叶理)。膝折作用发生在早元古宙时期绿片岩相的变质环境中。本区金的矿化、运移、沉淀与韧性剪切带的活动(第二期变形)有密切关系。膝折作用与韧性剪切带叠加的构造部位,是寻找金矿的有利位置。

The granite-greenstone terrain of 'Dongwufenzi Group'in the western Guyang area underwent four episodes of deformation during the period of late Archean to early Proterozoic.Kinking ia this area occurred under greenshist facies during the early Proterozoic and was mainly developed in foliated and mylonitic rocks. The uniclinal and asymmetric conjugate kinks can be due to the compression at an oblique angle of 30°r so with the layers(or foliations), and the formation of conjugate kinks was due to the compression parallel to the layers(or foliations). Transport, procipitation, and mineralization of hydrothermal solution forming gold deposit were intimately related to the activity of ductile shear zones,and therefore the locations where the kinking was superimposed on the ductile shear zones, and the sections were emplaced by the potassic granite are the favourable tectonic posi-ton in searching for gold deposits.