• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Asian earth sciences >Petrochemistry of ultrapotassic tephrites and associated cognate plutonic xenoliths with carbonatite affinities from the late Quaternary Qa'le Hasan Ali maars, central Iran
【24h】

Petrochemistry of ultrapotassic tephrites and associated cognate plutonic xenoliths with carbonatite affinities from the late Quaternary Qa'le Hasan Ali maars, central Iran

机译：来自伊朗中部第四纪晚期Qa'le Hasan Ali maars的碳酸盐岩亲和力的超钾辉石陨石及其伴生的同质古生物异岩石化

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The Quaternary Qa'le Hasan Ali (QHA) maars in central Iran occur at the intersection of the north-south Nayband fault, which defines the western boundary of the Lut micro-continental block, and a system of northwest-southeast faults, subparallel to the Zagros suture zone, that formed during the Arabian-Eurasian collision. These post-collisional maars intrude Eocene volcanic rocks of the Urumieh-Dokhtar mag-matic belt, which was generated by the subduction of Neotethys oceanic lithosphere below Iran. The highly potassic, Ti-phlogopite + Mg-rich (Fo_(89-92)) olivine + diopside-augite + aegirine-augite basanite tephrites forming the tuff rims of the QHA maars contain tephrite-coated plutonic xenoliths, some of which are interpreted as co-genetic with the tephrites based on their similar mineralogy and Sr isotopic composition (~(87)Sr/~(86)Sr = 0.70590). Cognate plutonic xenoliths have up to ～20 vol% calcite, considered to be magmatic calcite because of its grain size, which is similar to feldspars and aegirine-augite pyroxenes in these rocks, the occurrence of fine-grained inclusions of pyroxene and apatite within these calcite grains, and the similarity of the Sr-isotopic composition of this calcite with the other minerals in these rocks. The fact that the magmatic calcite has remained intact and did not volatilize during the transport of these xenoliths to the surface in the hot tephrite magma implies a short transit time, indicating that they are samples of a shallow plutonic complex, as does the presence of anorthoclase in these plutonic xenoliths. Their high modal proportion of magmatic calcite suggests that this shallow plutonic complex has affinities with carbonatites. The magmatic calcite-bearing plutonic xenoliths have high LREE/HREE ratios and contain REE-rich allanite (with up to ～20 wt% LREE) and britholite (～60 wt% LREE) that make up ～3 modal percent of the most calcite-rich samples. Similar to many post-collisional highly potassic rocks formed in the Alpine-Himalayan collision zone, the highly potassic basanite tephrites of the QHA maars have high ~(87)Sr/~(86)Sr and low ( _(Nd) (-1.3 to-3.4), distinct from converting asthenosphere, and they are depleted in Nb and Ta relative to Ba and La. They formed by small degrees of partial melting of lower continental lithospheric mantle metasomatized by both H_2O and CO_2-rich fluids derived from subducted Neotethys oceanic crust and sediments during the collision of the Arabian and Eurasian plates.
机译：伊朗中部的第四纪Qa'le Hasan Ali（QHA）马尔斯发生在南北Nayband断层的交汇处，该断层定义了Lut微洲块的西部边界，以及西北-东南断层的系统，与Zagros缝线区，该缝线区是在阿拉伯-欧亚碰撞中形成的。这些碰撞后的泥浆侵入了Urumieh-Dokhtar岩浆带的始新世火山岩，该岩体是由伊朗下的新特提斯洋岩石圈俯冲而产生的。钾含量高的钛金云母+富镁（Fo_（89-92））橄榄石+透辉石-augite +精铜-钠铁矾石辉绿岩形成了QHA麻岩的凝灰岩边缘，其中含有球铁矿涂层的深部异种岩。由于它们的相似的矿物学和Sr同位素组成而与辉长岩共生（〜（87）Sr /〜（86）Sr = 0.70590）。同源的深部异质石具有高达〜20vol％的方解石，由于其晶粒尺寸而被认为是岩浆方解石，类似于这些岩石中的长石和aegirine-augite辉石，在这些岩石中出现了细粒的辉石和磷灰石夹杂物方解石晶粒，以及该方解石的Sr同位素组成与这些岩石中的其他矿物的相似性。岩浆方解石在热异色岩岩浆中将这些异种岩运到地表的过程中仍保持完整且不会挥发，这一事实意味着传输时间很短，这表明它们是浅成岩复合体的样品，而正钙石的存在也是如此。在这些深成的异岩中。他们的岩浆方解石的高模态比例表明，这种浅成岩的复合体与碳酸盐岩有亲和力。含岩浆方解石的生屑异种岩具有较高的LREE / HREE比率，并含有富含REE的尿石（含量高达〜20 wt％LREE）和方解石（〜60 wt％LREE），占大多数方解石的〜3模态百分比。丰富的样本。类似于在阿尔卑斯山-喜马拉雅碰撞带中形成的许多碰撞后的高钾质岩石，QHA麻岩的高钾质玄武岩陨石具有〜（87）Sr /〜（86）Sr的高和低（_（Nd）（-1.3至3.4），与转变软流层不同，它们相对于Ba和La贫化了Nb和Ta。它们是由俯冲的新特提斯潜流的富含H_2O和CO_2的流体交代后的下部大陆岩石圈地幔小部分熔融形成的。阿拉伯板块与欧亚板块碰撞时的洋壳和沉积物。

著录项

相似文献

  • 外文文献
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号