| 三塘湖盆地二叠系芦草沟组喷爆岩岩石学、矿物学特征及相关问题探讨 |
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| 引用本文： | 李哲萱,柳益群,周鼎武,焦鑫,南云.三塘湖盆地二叠系芦草沟组喷爆岩岩石学、矿物学特征及相关问题探讨[J].沉积学报,2019,37(3):455-465. |
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| 作者姓名： | 李哲萱 柳益群 周鼎武 焦鑫 南云 |
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| 作者单位： | 1.大陆动力学国家重点实验室, 西北大学地质学系, 西安 710069; |
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| 基金项目： | 国家自然科学基金项目（41572086，41802120）；中国博士后基金（2018M633557） |
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| 摘 要： | 在对新疆北东部三塘湖盆地二叠系芦草沟组黑色细粒岩系进行研究时发现,这套长期被当作由黑色泥岩、凝灰岩和碳酸盐岩组成的岩系里还发育一套既不同于陆源碎屑、内碎屑沉积岩,也不同于热水沉积岩(喷流岩)的岩石,认为是一套以夹层形式发育在纹层状泥/页岩中,由气、液、固三相共存的深源岩浆—热液物质流体上涌进入湖(海)底喷流通道,由喷口喷出后与热液流体或与湖(海)水混合沉积形成的沉积岩—喷爆岩。喷爆岩呈薄层—纹层状展布,矿物组成种类单一,以不稳定、次稳定矿物为主。晶质颗粒碎屑或团块均呈大小混杂、形态各异的棱角状,分选差,分布无规律。基于大量岩芯、岩石薄片观察,结合电子探针及相关数据,以构成岩石碎屑颗粒的主要组成矿物为依据,将喷爆岩分为方解石喷爆岩、白云石喷爆岩、透辉石喷爆岩及长英质喷爆岩四类,并详细论述了各类岩石学、矿物学特征。研究结果显示构成喷爆岩的碎屑颗粒不再是传统认识的来自周缘母岩风化搬运或热液沉淀,而是在陆内裂谷欠补偿湖盆背景下、源自地球内部不同深度、不同性质的岩浆—热液物质流体。在此基础上,对喷爆岩与碎屑沉积岩、火山碎屑岩及喷流岩区别进行讨论,认为喷爆岩分别在矿物组成、物质来源、分布规模、形成方式等方面有别于上述三者。
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| 关 键 词： | 喷爆岩 岩浆-热液喷流 岩矿特征 芦草沟组 三塘湖盆地 |
| 收稿时间： | 2018-04-11 |
Petrology and Mineralogy Features of Magmatic-Hydrothermal Explosion Rocks in the Permian Lucaogou Formation of Santanghu Basin and Relative Discussions |
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| LI ZheXuan,LIU YiQun,ZHOU DingWu,JIAO Xin,NAN Yun.Petrology and Mineralogy Features of Magmatic-Hydrothermal Explosion Rocks in the Permian Lucaogou Formation of Santanghu Basin and Relative Discussions[J].Acta Sedimentologica Sinica,2019,37(3):455-465. |
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| Authors: | LI ZheXuan LIU YiQun ZHOU DingWu JIAO Xin NAN Yun |
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| Institution: | 1.State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi'an 710069, China;2.College of Earth Science and Engineering, Shandong University of Science and Technology, Qingdao, Shandong 266510, China |
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| Abstract: | In studying the black fine-grained rocks from the Permian Lucaogou Formation of Santanghu Basin, which has long been considered to consist mostly of mudstone, tuff, and carbonate rocks, a series of special laminar sedimentary rocks were discovered. These rocks are neither composed of terrigenous clastic sediments nor intraclast, and they are different from hydrothermal sedimentary rocks (exhalative rocks). Our research team named the series magmatic-hydrothermal explosion rock (MHER). MHER is formed by deep derived magmatic-hydrothermal material (and fluid), which usually forms via a vapor-liquid-solid mechanism, upwelling along the exhalite channels, erupting to the bottom of lake floor and then depositing with the surrounding hydrothermal fluids and water. MHER presents laminated sediments, distributed randomly, and dominantly composed of unstable minerals and metastable minerals with low-grade texture maturity. Based on the observation of a large number of cores and thin sections, in combination with electronic probes and other relative data, this paper classifies explosion rocks into four types according to their different mineral compositions:calcite explosion rock, dolomite explosion rock, diopside explosion rock, and felsic explosion rock. Petrology and mineralogy features of all types are described. MHER developed in an uncompensated lake of an intracontinental rift. The clastics of MHER were more likely derived from magmatic-hydrothermal material or fluid at a variety of depths in the Earth's interior, rather than weathered source rocks or hydrothermal precipitation. This paper also discusses the differences between MHER, sedimentary clastic rock, pyroclastic rock, and exhalaite. Rock-forming material sources, distribution scale, and forming mechanisms can distinguish MHER from the rocks mentioned above. |
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| Keywords: | magmatic-hydrothermal explosion rocks hydrothermal fluids exhalative petrology and mineralogy features Lucaogou Formation Sangtanghu Basin |
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