Chemistry and distribution of accessory Ni, Co, Fe arsenic minerals in the Pechenga Ni-Cu deposits, Kola Peninsula, Russia

被引:6
作者
Abzalov, MZ
Brewer, TS
Polezhaeva, LI
机构
[1] Univ Leicester, Dept Geol, Leicester LE1 7RH, Leics, England
[2] Russian Acad Sci, Kola Sci Ctr, Apatity 184200, Russia
[3] Western Min Corp, Melbourne, Vic, Australia
关键词
D O I
10.1007/BF01172481
中图分类号
P3 [地球物理学]; P59 [地球化学];
学科分类号
0708 ; 070902 ;
摘要
Ni, Co, Fe arsenic minerals are common accessory phases associated with both the Ni-Cu mineralization and country rock sulphides of the Pechenga complex. The majority of the arsenic minerals fall in the cobaltite-gersdorffite series, with minor arsenopyrite, nickeline and maucherite. These minerals are regularly distributed between different types of mineralization. Nickeline, maucherite and gersdorffite occur mainly in hydrothermally altered Ni-Cu sulphide ores, in particular stringer zone sulphides and mineralized talc-carbonate rocks. Arsenopyrite occurs only in pentlandite-free assemblages of the host shales, mainly in remobilized iron sulphide mineralization. The concentrations of Ni and Co in arsenopyrite decrease with the distance from the Ni-Cu bearing intrusions. Cobaltite is an ubiquitous mineral, but Ni-rich cobaltite occurs mainly in the Ni-Cu ores. In general, the transition from Ni-Cu ores to country rocks is marked by the change from Ni-arsenides to Ni-Co sulpharsenides and, finally, to Fe sulpharsenides. Sedimentary pyrite in sulphidic shales contains up to 1.8 wt.% As and was initially enriched in arsenic during sedimentation and diagenesis. Metamorphic recrystallization of authigenic As-bearing pyrite to As-free pyrrhotite led to significant liberation of arsenic during metamorphism. The mobilized arsenic could have been carried by associated metamorphic fluids and then participated in the low-grade alteration of the ultramafic rocks and associated Ni-Cu sulphide ores.
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页码:145 / 161
页数:17
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