| 西昆仑塔什库尔干下-中侏罗统龙山组沉积构造背景分析 |
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| 引用本文： | 曾忠诚,边小卫,张若愚,孔文年,陈宁,赵端昌,赵江林.西昆仑塔什库尔干下-中侏罗统龙山组沉积构造背景分析[J].吉林大学学报(地球科学版),2019,49(4):1039-1052. |
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| 作者姓名： | 曾忠诚 边小卫 张若愚 孔文年 陈宁 赵端昌 赵江林 |
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| 作者单位： | 1. 陕西省矿产地质调查中心, 西安 710068;2. 陕西省地质调查院, 西安 710054 |
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| 基金项目： | 中国地质调查局项目（1212011120533，12120114081901）；第二次青藏高原综合科学考察研究（2019QZKK0807） |
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| 摘 要： | 新疆塔什库尔干地区下-中侏罗统龙山组，位于最新填绘的唐盖河-新迭村构造混杂岩带（康西瓦构造带）的南侧，总体为一套青灰色-灰色碳酸盐岩-碎屑岩沉积，主要以泥灰岩和杂砂岩为主，源区岩石没有经过充分的搬运、分选，成熟度比较低。稀土元素特征表现为轻稀土元素富集、重稀土元素相对平坦和Eu亏损明显的特征，与典型上地壳非常相似；而微量元素质量分数也接近于大陆上地壳值；说明下-中侏罗统龙山组物源来自上地壳。沉积环境综合分析表明，龙山组沉积环境为浅海陆棚-近滨-前滨环境，表现出进积特征，总体为一个海退序列，反映了寒冷干燥的气候条件下，海平面下降、残留海盆收缩的沉积构造环境。从物源区构造背景来看，龙山组以活动大陆边缘为主，兼具大陆岛弧性质。结合区域地质构造背景，龙山组为羌塘地块和昆仑地块拼合之后形成的残留洋边缘沉积，其主要物源来源于其北侧的康西瓦构造带。
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| 关 键 词： | 西昆仑 塔什库尔干 龙山组 沉积环境 构造背景 |
| 收稿时间： | 2018-01-24 |
Tectonic Setting of Lower-Middle Jurassic Longshan Formation in Taxkorgan Area,West Kunlun |
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| Zeng Zhongcheng,Bian Xiaowei,Zhang Ruoyu,Kong Wennian,Chen Ning,Zhao Duanchang,Zhao Jianglin.Tectonic Setting of Lower-Middle Jurassic Longshan Formation in Taxkorgan Area,West Kunlun[J].Journal of Jilin Unviersity:Earth Science Edition,2019,49(4):1039-1052. |
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| Authors: | Zeng Zhongcheng Bian Xiaowei Zhang Ruoyu Kong Wennian Chen Ning Zhao Duanchang Zhao Jianglin |
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| Institution: | 1. Shaanxi Mineral Resources and Geological Survey, Xi'an 710068, China;2. Shaanxi Institute of Geological Survey, Xi'an 710054, China |
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| Abstract: | The Lower-Middle Jurassic Longshan Formation is located at the south of Tanggai River-Xindie County tectonic melange belt (KSTB) in Taxkorgan area, Xinjiang. The clastic sedimentary rocks are dominated by marls and greywackes, and are a set of steel grey-gray carbonate clastic sediments with low maturity. Their source rocks have not been fully handled and sorted. The REE distribution patterns are uniform and similar to typical post-Archean shales and upper continental crust, with enriched LREE, flat HREE, and negative Eu anomaly. A sedimentary environment analysis shows that the sediments belong to shallow shelf-nearshore-foreshore environment,and are characterized by progradation sedimentation, indicating a regressive sequence. The sedimentary rock formed in tectonic-sedimentary setting of sea level decline and residual sea basin contraction. The tectonic settings of the provenance mainly belong to active continental margin with characteristics of continental island arc. Based on the regional tectonic environment, we conclude that the Middle-Lower Jurassic Longshan Formation is the sediments of residual marginal ocean, formed by completed Qiangtang block and Kunlun block, the source of Longshan Formation comes from the KSTB, the north of Longshan Formation. |
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| Keywords: | West Kunlun Taxkorgan Longshan Formation depositional environment tectonic setting |
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