川西盐边县红格钒钛磁铁矿中镍钴硫化物的铂族元素地球化学特征

发布时间：2018-04-08 15:21

本文选题：红格矿床白草矿段　切入点：镍钴硫化物　出处：《地质论评》2017年04期

【摘要】：世界上尚未发现过V—Ti磁铁矿和硫化物矿床共生,在川西延边县红格矿床,原认为在矿体底部存在一个富含PGE、Cr的层位,但我们在多个钻孔中取样分析,均未发现。然而我们发现在红格矿床白草矿段存在大量的块状硫化物矿体,硫化物贯入铁矿后,可叠加形成镍—钴—铁矿体。块状硫化物矿石主要成分为磁黄铁矿(94%)、镍黄铁矿、黄铜矿,少量普通辉石、次透辉石、古铜辉石、普通角闪石、金云母、磁铁矿、钛铁矿、中长石等。其中Ni 0.72%～0.90%,Co 0.10%。主要赋存在磁黄铁矿中。通过铂族元素分析发现,块状硫化物(磁黄铁矿)Cu/Pd为12908～15109,含硫化物3%的贯入式铁矿Cu/Pd为24520。Cu/Pd比值远高于原始地幔值,暗示有少量硫化物在岩浆源区的残留。同时,在铁矿形成之前已发生过硫化物的熔离。红格地区样品的Pd/Ir值变化范围为2.8～30主要集中在8～14附近,可见红格地区经历过很强的岩浆结晶作用。红格矿床的PGE元素已发生明显的分异现象,暗示硫化物与铁可能在流体中有共同富集的情况。不同矿段的PGE含量有明显差异,很难用一个岩浆房进行解释,可能是多级岩浆房岩浆演化的产物。暗示深部还有岩浆房,在地下深处,还可以找Ni—Cu—PGE和Fe—Ti—V矿床。
[Abstract]:The V-Ti magnetite and sulfide deposits have not been found in the world. In the Hongge deposit in Yanbian County, western Sichuan, it was thought that there was a layer rich in PGE-Cr at the bottom of the orebody, but we did not find it by sampling and analyzing in several boreholes.However, it is found that there are a large number of massive sulphide orebodies in the Baicao section of the Hongge deposit, which can be superimposed to form nickel-cobalt-iron ore bodies after the sulfides penetrate into the iron ores.The main components of massive sulphide ores are pyrrhotite, nickel pyrite, chalcopyrite, a small amount of ordinary pyroxene, subdiopyroxene, palaeopyroxene, common hornblende, phlogopite, magnetite, ilmenite, meso-feldspar, etc.Among them, Ni 0.72 is 0.90 and Co is 0.10.Mainly occurs in pyrrhotite.By the analysis of platinum group elements, it is found that the Cu/Pd ratio of massive sulphide (pyrrhotite Cu / PD = 12908 / PD = 15109) is much higher than that of the original mantle, indicating that a small amount of sulphide remains in the magma source region, and the Cu/Pd ratio of the intrusive iron ore containing 3% sulphide is much higher than that of the original mantle.At the same time, prior to the formation of iron ore, sulfide melting has occurred.The variation range of Pd/Ir value in Hongge area is mainly in the vicinity of 8Q14. It can be seen that the Hongge area has experienced strong magmatic crystallization.The PGE elements of the Hongge deposit have been obviously differentiated suggesting that the sulphide and iron may be enriched together in the fluid.The PGE content of different ore sections is obviously different, which is difficult to explain by one magma chamber, which may be the product of multi-stage magma chamber magma evolution.It suggests that there are magma chambers in the deep, and Ni-Cu-PGE and Fe-Ti-V deposits can be found in the deep underground.
【作者单位】：成都理工大学地球科学学院;澳大利亚国立大学;湖南省地质调查院;
【基金】：国家自然科学基金资助项目(批准号:41073022)的成果~~
【分类号】：P618.2

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