Acta Scientiarum Naturalium Universitatis Pekinensis

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PEGs Abundance Patterns and Its Implications of Carboniferous Volcano Zone to South and North of Turpan-Hami Basin, Xinjiang Uigur Autonomous Region

GAO Honglin1,MU Zhiguo1,JIN Xindi2,ZHU Heping2   

  1. 1Department of Geology, Peking University, Beijing, 100871;2Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029
  • Received:2000-01-26 Online:2001-05-20 Published:2001-05-20



  1. 1北京大学地质学系,北京,100871;2中科院地质与地球物理研究所,北京,100029

Abstract: The PGEs abundance patterns of residual mantle rock with a peleo-subduction background is characterized by Pd, Pt depletion and Ir, Ru relatively enrichment, while the basalt and basic dyke by the processing of partial melt in the same background take an opposite feature of Pd, Pt enrichment and Ir, Ru depletion. the existence of fluid in the subduction zone increases the degree of partial melt on the one hand, and on the other, activates the activity of Pd, Pt compare to Ir, Ru, and thus reduces the Pd/Ir and Pt/Ru in residual mantle rock. The PGEs patterns for basalt and basic dyke from two Carboniferous volcano zones to south(Qoltag)and north(Bogda)Turpan-Hami basin, XinJing Uigur Autonomous Region, take a shape of gentle positive inclined curve with lower Pt and Pd differentiation and lower Σ PGEs. All these features are obviously different from that of basic dyke and basalt from typical ophiolite and therefore the author believe that their fluid-rich paleo-subduction zone environment can be ruled out.

Key words: to south(Qoltag)and north(Bogda) Trupan-Hami basin, Xinjing Uigur Autonomous Region, Carboniferous volcano zones, peleo-subduction background, PGEs abundance patterns

摘要: 古俯冲带背景下的残余地幔岩的PGEs配分以Pd, Pt明显亏损和Ir, Ru相对富集为特征,而部分熔融产物的玄武岩和基性岩脉则呈现相反的Ir, Ru明显亏损和Pd, Pt相对富集特征。俯冲带中流体的参与一方面增加了部分熔融程度,有利于Pd, Pt从原始地幔进入熔融相;另一方面,流体的作用使得Pd, Pt相对于Ir, Ru迁移活动性效率提高,造成地幔岩中w(Pd)/w(Ir)和w(Pt)/w(Ir)比值很低。新疆吐鲁番—哈密盆地南缘觉罗塔格和北缘博格达两个石炭纪火山岩带中的玄武岩和基性岩墙群PGEs配分曲线均呈缓的正倾斜曲线形式,PGEs总量和Pd, Pt分异程度均很低,与典型蛇绿杂岩带中的基性岩明显不同,据此可以认为两个岩浆带并不具备古板块俯冲带的构造背景。

关键词: 新疆吐哈盆地南北缘, 石炭纪火山岩带, 古俯冲带背景, 铂族元素配分

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