塔里木北缘及邻区海西期碱性岩岩石化学特征及其大地构造意义

塔里木地台北缘及邻区发育一套以正长岩、石英正长岩、霓辉正长岩、霓霞正长岩、碱性花岗岩类为代表，包括碱性辉长岩、碱长花岗岩、霓辉花岗岩、角闪正长岩、碱性辉石闪长岩、煌斑岩等类岩石在内的碱性侵入岩体．它们具有近东西向的带状分布特征．主体形成于海西期．相当于泥盆-二叠纪．钾钠含量较高，具有碱性岩类的岩石化学特征．构成一条碱性侵入岩带．其时空分布与北山-阿拉善地区的碱性岩带基本一致．该碱性岩带反映出在泥盆-二叠纪期间．塔里木地台北缘及邻区处于造山期后的拉张构造环境．

PETROCHEMISTRY AND TECTONIC SIGNIFICANCE OF HERCYNIAN ALKALINE ROCKS ALONG THE NORTHERN MARGIN OF THE TARIM PLATFORM AND ITS ADJACENT AREA

A set of alkaline-rich intrusive complexes occurs along the northern margin of Tarim platform and its adjacent area. Such types of rocks have been found in this area as syenite, quartz syenite, aegirine-augite syenite, nepheline syenite, alkaline granite, alkaline gabbro, alkaline-feldspar granite, aegirine-augite granite, hornblende syenite, alkaline-augite diorite and lamprophyre. Forming in Hercynian, about Devonian to Permian, these complexes distribute in east-west direction, being rich in Kalium and Natrium, having petrochemistry features of alkaline-rich rocks, making up a alkaline to alkaline-rich rock belt. This belt is comparable to Beishan-Alxa alkaline rock belt. We can deduce from this alkaline rock belt that the northern margin of Tarim platform and its adjacent area is in a extensive tectonic environment during Devonian and Permian.