| 库车坳陷三叠系碎屑重矿物成分及其物源属性 |
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| 引用本文： | 王松,李双应,杨栋栋,程成.库车坳陷三叠系碎屑重矿物成分及其物源属性[J].地质学报,2014,88(5):918-931. |
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| 作者姓名： | 王松 李双应 杨栋栋 程成 |
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| 作者单位： | 合肥工业大学，合肥，230009;合肥工业大学，合肥，230009;合肥工业大学，合肥，230009;合肥工业大学，合肥，230009 |
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| 摘 要： | 库车坳陷三叠系发育良好，出露齐全，主要由陆相碎屑岩组成。本文运用电子探针微区成分分析方法，对库车坳陷北部三叠系砂岩中石榴石、电气石、铬尖晶石进行了矿物化学成分分析。结果显示，碎屑石榴石主要富含铁铝榴石，其次为镁铝榴石、锰铝榴石，钙铝榴石含量较低，他们主要来自于低级-高级变质岩和花岗岩；电气石主要来自于变质沉积岩和花岗岩；铬尖晶石则主要源自岛弧玄武岩、洋岛玄武岩和与俯冲相关的橄榄岩。综合石榴石与电气石研究结果表明，上三叠统碎屑物质更多的来自于高级变质岩和花岗岩，而下三叠统碎屑物质主要源自低级变质岩和花岗岩。通过对比西天山榴辉岩、片麻岩中石榴石成分，本文所研究的高镁石榴石以低钙铝榴石含量与榴辉岩中石榴石相区别，而与片麻岩中石榴石成分相似。西天山榴辉岩在三叠纪时期可能尚未剥露至地表，但片麻岩已有相当范围的出露。上三叠统的碎屑铬尖晶石可能主要来自于中天山及南天山的岛弧岩浆岩及蛇绿岩，部分源自洋岛玄武岩，为南天山为多岛海造山提供了沉积学证据。
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| 关 键 词： | 南天山 库车 三叠系 重矿物 物源 |
| 收稿时间： | 2013/6/19 0:00:00 |
| 修稿时间： | 2013/11/4 0:00:00 |
Provenance of the Triassic Sandstones in the Kuqa Depression: Constraints from Heavy Minerals Chemistry |
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| WANG Song,LI Shuangying,YANG Dongdong and CHENG Cheng.Provenance of the Triassic Sandstones in the Kuqa Depression: Constraints from Heavy Minerals Chemistry[J].Acta Geologica Sinica,2014,88(5):918-931. |
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| Authors: | WANG Song LI Shuangying YANG Dongdong and CHENG Cheng |
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| Institution: | School of Resources and Environmental Engineering, Hefei University of Technology,School of Resources and Environmental Engineering, Hefei University of Technology |
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| Abstract: | The Triassic in the Kuqa depression is well exposed, mainly composed of terrestrial clastic rocks. Our research focuses on chemical characteristics of detrital heavy mineral in the Triassic sandstones using the electron microprobe. Chemical compositions of the detrital garnets suggest that they mainly comprise almandine, pyrope, spessartine and grossular garnets. They are derived from the low-grade to high-grade metasedimentary rocks and granitoid. The detrital tourmalines are sourced from metasedimentary rocks and granitoid and the parent rocks of the detrital chrome spinels are arc basalt, ocean island basalt and subduction related peridotite. The detrital component of the upper Triassic derived from high-grade metasediments and granitoid is much more than that of the lower Triassic. Comparing with the garnets from eclogite and gneiss in the western Tianshan, the detrital garnets composition has remarkable difference on grossular content with those from eclogite and are similar to those in gneiss, which suggest that the eclogite has not been exhumed at surface yet while the gneiss is well exposed at Triassic time. The detrital chrome spinels in the upper Triassic are mainly derived from arc magmatic rock and ophilite in the central Tianshan and the south Tianshan, some of which are sourced from ocean island basalts, which provide sedimentary evidence for the archipelagic orogenisis of the south Tianshan. |
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| Keywords: | the south Tianshan Kuqa Triassic heavy mineral provenance |
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