帕米尔构造结位于青藏高原北缘,记录了自新元古代晚期以来到新生代完整的特提斯构造演化过程.在长期的构造-岩浆演化过程中,发育了不同时代、不同类型的成矿事件.野外调查表明,在帕米尔北东段,发育了含绿柱石的伟晶岩及含氟碳铈矿的碳酸岩(碳酸岩-伟晶岩组合).通过独居石及锆石U-Pb定年,识别出该区两期伟晶岩带(包括碳酸岩),分别是新生代和中生代(19～18 Ma和200 Ma),其中早期含绿柱石伟晶岩形成于古特提斯洋关闭后的伸展阶段,而新生代含氟碳铈矿碳酸岩-伟晶岩组合,与新生代陆内走滑伸展事件相关,表明帕米尔构造结伸展走滑启动的时间可能在19 Ma.结合区域地球化学异常特征,表明在帕米尔地区有望在稀有、轻稀土找矿上获得突破.

西昆仑-喀喇昆仑位于青藏高原北缘,是特提斯构造域的重要组成部分.近年来在该区有色金属找矿勘查工作取得重大突破,相继发现一批超大型、大中型铅锌矿床.罗布盖子大型铅锌矿位于甜水海-喀喇昆仑有色金属成矿带最西段,获得详查资源量大于100万t.笔者报道了该矿床的基本地质特征,确定该矿床的形成与白垩纪岩浆岩演化晚期的热液有关,并获得与成矿关系密切的淡色脉体独居石U-Pb年龄为(99.25±0.78) Ma,进一步证实该矿床属于岩浆热液矿床.依据区域地球化学勘查及区域地质背景的综合分析,认为在甜水海—喀喇昆仑分布的巨型铅锌矿带,受控于侏罗纪—白垩纪火山-沉积盆地及白垩纪岩浆岩,该成矿带具有重大找矿潜力.

The study in this paper shows that the intrusive complex in north belt of the eastern part of western Kunlun is composed of gabbro, diorite, granodiotite and granite and zonally compound a tectonic magma belt in the E-W direction. The petrochemical characteristics indicate that the medium and acid intrusives are of high potassium clac alkaline I type granites with the small variation of ∑REE between 178.3×10 -6 and 229.0×10 -6 . The ratios of LREE/HREE of the diorite and the granite are 3.8 ～5.1 and 6.7～7.7 respectively all both have the similar REE distribution patterns. Morever, the geochemical characteristics of the trace elements in both rocks are completely similar to that of Chile arc granite. The ratio of 147 Sm/ 144 Nd in the rocks varies from 0.094 to 0.114, 143 Nd/ 144 Nd from 0.512 053 to 0.512 19, T DM from 1 381 to 1 535Ma, e Nd( t ) has a small variation with the average of -10.46. All of these imply that the intrusive rocks belong to the evolutionary series with the same source as the result of the crustal partial remelting. Based on the characteristics petrochemistry, the trace elements and the isotopic geochemistry, it has been suggested of that the intrusive rocks in the study area are formed in the environment of magma arc in the continental rim. The magma of these intrusives are mainly derived from the partial melting of Paleo Proterozoic metamorphic stratra, but contaminated by the Meso Proterozoic volcanic rocks in course of emplacement.