ISSN 1009-6248CN 61-1149/P 双月刊

主管单位:中国地质调查局

主办单位:中国地质调查局西安地质调查中心
中国地质学会

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    金宝山铂钯矿与国外大型层状岩体中的铂钯矿床对比

    Comparison of Jinbaoshan PGE Deposit and other Foreign PGE Deposits in Large Layered Intrusion

    • 摘要: 金宝山铂钯矿床是我国目前发现的最大的独立铂钯矿床,而世界上著名的铂族元素矿床主要有Bushveld和Stillwater等矿床.笔者总结了金宝山与Bushveld和Stillwater矿床在构造背景、岩体类型、岩石组合、地球化学等方面的异同:金宝山矿床(260Ma)的产出构造背景是峨眉山大火成岩省,Bushveld产于克拉通区(2.06Ga),Stillwater(2.70)产于陆内裂谷,总体而言,均产于较稳定的构造环境.但金宝山矿床形成时代新,构造环境的稳定程度较二者差一些,这种差异在岩体规模上反映出来,虽然三者的岩体类型都属层状岩体,但金宝山岩体出露面积不到3km2,远小于Bushveld(65 000 km2)和Stillwater(376km2)岩体.金宝山岩体的岩石类型较为简单,岩石类型主要为单辉橄榄岩,以及少量橄榄辉石岩和辉石岩,而形成Bushveld和Stillwater岩体母岩浆的种类多,分异彻底,岩石类型十分丰富.与Bushveld和Stillwater岩体相比,金宝山岩体的橄榄石、辉石成分变化较小;地球化学以贫Si、富Mg为特征.金宝山矿床的赋矿层位和含矿岩性与Bushveld的Platreef层相似,金宝山矿床PGE最高品位为1.5×10-6,低于Stillwater的J-M层(20×10-6)、Bushveld的Platreef(5×10-6)和Merensky(5×10-6~7×10-6).岩体规模、岩浆分异程度、熔离作用等的差异致使金宝山矿床的规模远不及Bushveld和Stillwater矿床.

       

      Abstract: The Jinbaoshan Pt-Pd deposit is the largest independent Pt-Pd deposits in China at present, and the world famous PGE deposits are mainly Bushveld and Stillwater deposits. In this paper, the similarities and differences of tectonic setting, intrusion type, rock assemblages, geochemistry among Jin Baoshan, Bushveld and Stillwater deposits have been summarized. The results show that the Jinbaoshan deposit (260Ma) was occurred in the Emeishan Large Igneous Province, which is located at relatively stable tectonic environment, but its stable degree of tectonic environment is less than Bushveld (2.06Ga) that developed from craton and Stillwater (2.70Ga) from intracontinental rift, and these differences have been reflected in the scale of intrusion. Although these three intrusions are layered intrusion, the exposed area of the Jinbaoshan intusion is less than 3 km2, far less than the Bushveld (65 000 km2) and Stillwater (376 km2). The rock types of the Jinbaoshan intusion is relatively simple, are mainly wehrlite and a small amount of olive pyroxenite and pyroxenite, while Bushveld and Stillwater are derived from a variety of primary magmas with thoroughly differentiation and have many rock types from ultramafic rock to mafic rocks. Compared with the Bushveld and Stillwater, the compositions of olivine and pyroxene in the Jinbaoshan vary small; On geochemistry, the rocks of the Jinbaoshan are characterized by silicon-poor and magnesium-rich. The occurrence and rock lithology of ores in the Jinbaoshan deposit are similar to the Platreef layers in Bushveld. The highest contents of PGE in the Jinbaoshan deposit is 1.5 ppm, lower than the J-M layer in Stillwater (20×10-6), the Platreef (5×10-6) and Merensky (5×10-6~7×10-6) in Bushveld. Affected by the differences in the scale of the intrusion, the degree of magmatic differentiation and liquation, the size of the Jin Baoshan deposits is far less than the Bushveld and Stillwater.

       

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