汉南金水-青泥坑镁铁层状杂岩体岩石层序与铂矿化

汉南镁铁层状杂岩是出露于扬子板块北缘的一个大岩体，据测同位素年代为1121-748Ma，属中元古侵位于西乡群变质岩系的岩体。杂岩体按岩石类型分为由辉长岩类组成的上部带和由辉石-橄榄岩组成的下部岩带构成。岩石化学、矿物化学和微量元素地球化学的演变与层状岩序变化相当一致。韵律层发育部位，矿物组分多次重复出现。层状岩序的稀土总量（La/Yb）N值完全符合随着层序增高、分馏趋势增加一般规律。本文系统阐述了杂岩体各为岩石的铂族元素分配特征，初步确定了铂矿化与铜镍矿化产出部位。在分析了杂岩体产出构造环境的基础上，探讨了杂岩体原始岩浆性质，估算了部分熔融程度。

Mafic Layered Comples Body and Its Platinum-Bearing Nature in Jinshui-Qingnikeng Hannan

Jinshuui-Qingnikeng mafic layered complex body is located north rim of Yangtze plate, east-north position of Hannan terrain.It intrudes into Xixiang Group,out-cropping, more than 500km2 and is mainly composed of gabbroites, partly ultramafic py-roxenite and peridotite. According to layered rock-sequence and types, the body is divided into two zones; the upper gabbroites and the lower zone composed of pyroxenite, peridotite and coarse altered gabbroite. It is studied that evolution of petrochemisry, mineral chemistry and trace element geochemistry is consistent with that of layered rock sequence. The position of developing rhythemtic units shows there had been many time emplacement activity of magma forming complex body. Besides, this paper has shown that the total value of REE and (La/Yb)N increase with rise of layered rock sequence yet, those coincidence with general low of REE fractionation tendency. In this paper, a systematic explantion for PGE distribution characteristics of various rocks in the complex body has been made, and the occurrence places of mineralization of Pt and Cu-Ni has preliminarily been determined and minerogenesis of PGE has also been dis-cussed. After analysing geological tectonic environment in which the complex body forms, it is discussed character of parental magma, and estimated partly melting degree.