High-alumina basalts from the Bogda Mountains suggest an arc setting for Chinese Northern Tianshan during the Late Carboniferous
High-alumina basalts from the Bogda Mountains suggest an arc setting for Chinese Northern Tianshan during the Late Carboniferous
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博格达山的高铝玄武岩表明晚石炭世中国北天山的弧形环境
DOI：
10.1016/j.lithos.2016.04.005
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发表时间：
2016-07
期刊：
影响因子：
3.5
通讯作者：
Liu Hai-Quan
中科院分区：
文献类型：
--
作者：
Xie Wei;Xu Yi-Gang;Chen Yi-Bing;Luo Zhen-Yu;Hong Lu-Bing;Ma Liang;Liu Hai-Quan
关于天山造山带晚古生代的构造背景一直存在较大争议，活动俯冲系统和板内大火成岩省是两个主要的学派。为了对这一问题提供制约，对博格达山晚石炭世高铝玄武岩(HAB)进行了年代学和地球化学分析。这些熔岩与长英质岩石呈整合接触，属上石炭统柳树沟群。两个长英质火成岩的锆石SHRIMP U-Pb定年进一步表明，它们主要喷发在315-319 Ma之间。博格达玄武岩熔岩被归类为HAB，因为它们的铝含量高达16%，而且它们的化学成分与阿留申和堪察加等现代弧的化学相似。具有大离子亲石元素(LILE)强烈富集性，Nb-Ta、Ti负异常强烈，铅正异常明显的特点。因此，它们与来自西伯利亚、峨眉山和塔里木大火成岩省的与地幔柱有关的玄武岩明显不同。相反，其类MORb的NdHf-Pb型同位素和弧状的微量元素表明，Bogda HAB可能是由沉积物来源的熔体交代的地幔楔形构造产生的。Bogda habs中单斜辉石斑晶的扇形和振荡分带可归因于岩浆上升过程中的快速动力结晶。铝含量高是由于斜长石成核延迟，可能是由于较高的晶化压力，而不是水含量。总体而言，我们的数据支持晚古生代的岛弧环境，可能与古天山洋向南俯冲有关。
Considerable debate persists as to the tectonic setting of the Tianshan Orogen during the Late Paleozoic, with active subduction system and intraplate large igneous provinces as two dominant schools. With aims of providing constraints on this issue, geochronological and geochemical analyses have been carried out on the Late Carboniferous high-Al basaltic lava (HAB) from the Bogda Mountains. These lavas, in conformable contact with the felsic rocks, belong to the Upper Carboniferous Liushugou Group. Zircon SHRIMP U–Pb dating of two felsic ignimbrites further suggest that they were mainly erupted during 315–319 Ma. The Bogda basaltic lava is classified as HAB given their high Al contents > 16% and their chemical resemblance to those from modern arcs such as Aleutian and Kamchatka. They are characterized by strong enrichment in large ion lithophile elements (LILE), strong negative Nb–Ta and Ti anomalies, and distinct positive Pb anomalies. Hence, they are significantly different from the mantle plume-related basalts, as exemplified by those from Siberian, Emeishan, and Tarim large igneous provinces. Instead, their MORB-like Nd–Hf–Pb isotopes and arc-like trace elements indicate that the Bogda HABs may have been generated from a mantle wedge metasomatized by sediment-derived melts. The sector and oscillatory zoning in clinopyroxene phenocrysts in the Bogda HABs is attributable to rapid dynamic crystallization during magma ascent. High Al content is due to delayed plagioclase nucleation likely by the high crystallization pressure rather than water content. Collectively, our data lend support to an island arc environment during the Late Paleozoic, probably related to southward subduction of the Paleo-Tianshan Ocean.
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影响因子：
6.1
作者：
Weifeng Zhang;Huayong Chen;Jinsheng Han;Liandang Zhao;Jianhan Huang;Juntao Yang;Xuelu Yan
通讯作者：
Weifeng Zhang;Huayong Chen;Jinsheng Han;Liandang Zhao;Jianhan Huang;Juntao Yang;Xuelu Yan
DOI：
--
发表时间：
2009
期刊：
Journal of Mineralogy and Petrology
影响因子：
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作者：
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通讯作者：
Lu Rong-hui
影响因子：
3.5
作者：
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通讯作者：
D. Draper;A. Johnston
影响因子：
3
作者：
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通讯作者：
Ning‐Bo Li;He‐Cai Niu;Q. Shan;Wubin Yang
影响因子：
3.8
作者：
A. Polat;A. Hofmann
通讯作者：
A. Polat;A. Hofmann