| 新疆北部地区二叠系幔源碳酸岩质喷积岩研究* |
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| 引用本文： | 柳益群,周鼎武,南云,焦鑫,李哲萱,李红,周小虎.新疆北部地区二叠系幔源碳酸岩质喷积岩研究*[J].古地理学报,2018,20(1):49-63. |
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| 作者姓名： | 柳益群 周鼎武 南云 焦鑫 李哲萱 李红 周小虎 |
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| 作者单位： | 1.西北大学大陆动力学国家重点实验室,西北大学地质学系,陕西西安 710069;2.山东科技大学地质科学与地质工程学院,山东青岛 266510 |
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| 基金项目： | Co-funded by General Program of the National Natural Science Foundation of China (Nos. 41272116, 41572086) and Foundation of State Key Laboratory of Continental Dynamics(Northwest University) (No. BJ08133-3) |
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| 摘 要： | 新疆北部地区的二叠纪芦草沟期发育陆内裂谷型欠补偿湖盆,形成了中二叠统芦草沟组的重要烃源岩系。该烃源岩系中夹有一套以深源碎屑为特征的新型沉积组合,即薄层、纹层状地幔岩浆—热液喷流型沉积岩——喷积岩。本文报道的碳酸岩质喷积岩包括喷爆岩和喷溢岩2种类型。碳酸岩质喷爆岩厚0.5~4 cm,岩石以微粒晶质方解石矿物为碎屑,方解石碎屑颗粒呈大小不一、形态各异的角砾状,星散分布于黑色基质中,并显示粒序特征;碳酸岩质喷溢岩多呈2~4 mm厚的纹层和2~3 cm厚的薄层被夹于黑色含油沉凝灰岩、含油凝灰质泥晶白云岩等纹层岩中。纹层中的方解石具有典型的镶嵌粒状结构、环带结构。喷爆岩中方解石的流体包裹体测温高达435 ℃以上;C-O、Sr-Nd同位素显示碳酸岩质喷积岩中的方解石源自地幔,但受到湖水的较大影响。研究表明,本区的碳酸岩质喷积岩是一种源自地幔的碳酸岩质岩浆—热物质流体喷发、溢流入湖底,与湖水混合沉积而成的一类新型沉积岩。
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| 关 键 词： | 碳酸岩 岩浆—热液喷流沉积岩 芦草沟组 二叠系 新疆北部地区 |
| 收稿时间： | 18 October 2017 |
Permian mantle-derived carbonatite originated exhalative sedimentary rocks in North Xinjiang |
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| Liu Yi-Qun,Zhou Ding-Wu,Nan Yun,Jiao Xin,Li Zhe-Xuan,Li Hong,Zhou Xiao-Hu.Permian mantle-derived carbonatite originated exhalative sedimentary rocks in North Xinjiang[J].Journal of Palaeogeography,2018,20(1):49-63. |
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| Authors: | Liu Yi-Qun Zhou Ding-Wu Nan Yun Jiao Xin Li Zhe-Xuan Li Hong Zhou Xiao-Hu |
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| Institution: | 1.State Key Laboratory of Continental Dynamics,Department of Geology,Northwest University,Xi'an 710069,Shaanxi;2.College of Earth Science and Engineering,Shandong University of Science and Technology,Qingdao 266510,Shandong |
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| Abstract: | In the Permian Lucaogou epoch, an underfilled intracontinental rift basin was developed in the North Xinjiang, which yields an important source rock of the Lucaogou Formation. A new series of sedimentary rocks that are laminated, thin bedded, carbonate rick and mantle-derived were observed in the source rock and termed as Exhalative Sedimentary Rocks (ESR). The carbonatite ESR in this paper include two types, Effusive Rocks and Explosive Rocks. The thickness of carbonatite Explosive Rocks ranges from 0.5~4 cm. Fine-grained calcite clasts distribute dispersedly in black matrix with various sizes and shapes and display normal grading. The calcite carbonatite originated Effusive rocks are characterized by 2~4 mm laminae and 2~3 cm thin bed, and are intercalated within oil-bearing sedimentary tuffs and tuffaceous dolostones. The calcites represent granular mosaic and zonal structure; homogenization temperatures of fluid inclusions reaches to 435℃. C-O and Sr-Nd isotope compositions indicate the calcite in canbonatite ESR was originated from mantle yet has been largely influenced by interaction with lake water. This study shows that the carbonatite ESR are the product of interaction between mantle-derived carbonatite melt/fluid and fresh lake water. |
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| Keywords: | carbonatite magmatic-hydrothermal exhalative sedimentary rocks Lucaogou Formation Permian North Xinjiang |
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