| 鄂尔多斯盆地三叠系延长组沉积演化及其与早印支运动关系的探讨 |
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| 引用本文： | 邓秀芹,蔺昉晓,刘显阳,庞锦莲,吕剑文,李士祥,刘鑫.鄂尔多斯盆地三叠系延长组沉积演化及其与早印支运动关系的探讨[J].古地理学报,2008,10(2):159-166. |
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| 作者姓名： | 邓秀芹 蔺昉晓 刘显阳 庞锦莲 吕剑文 李士祥 刘鑫 |
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| 作者单位： | 中国石油长庆油田公司勘探开发研究院 陕西西安710021 |
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| 摘 要： | 鄂尔多斯盆地延长组下部（长8-长10油层组）沉积特征与中、上部（长1-长7油层组）存在较大的差异。延长组下部沉积时，盆地西部和西南地区地形相对较平坦，以辫状河、辫状河三角洲及滨浅湖沉积为主，碎屑岩中化学性质不稳定的组分含量较高；长7沉积期，沉积格局发生重大变革，盆地西缘、西南缘地区发育冲积扇、扇三角洲沉积体系，拗陷幅度急剧增大，半深湖-深湖区范围可达10×10.4 km2以上，而且湖盆中心向西南迁移了几十公里，碎屑岩成分成熟度增高，岩矿组合具有显著的东西分异性。此外，从延长组凝灰岩的分布特征分析，长7底部沉凝灰岩分布稳定，为同期火山作用的产物，厚度由盆地西南向东北方向逐渐减薄至不发育。上述分析表明，长8沉积末期为湖盆沉积演化的重要转折期，盆地西缘和西南缘存在一次强烈的构造地质事件，火山活动频繁，为印支运动第一幕重要的表现形式。
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| 关 键 词： | 鄂尔多斯盆地 延长组 沉积演化 凝灰岩 早印支运动 |
| 文章编号： | 1671-1505(2008)02-0159-08 |
| 修稿时间： | 2007年8月13日 |
Discussion on relationship between sedimentary evolution of the Triassic Yanchang Formation and the Early Indosinian Movement in Ordos Basin |
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| Deng Xiuqin,Lin Fangxiao,Liu Xianyang,Pang Jinlian,Lü Jianwen,Li Shixiang,Liu Xin.Discussion on relationship between sedimentary evolution of the Triassic Yanchang Formation and the Early Indosinian Movement in Ordos Basin[J].Journal of Palaeogeography,2008,10(2):159-166. |
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| Authors: | Deng Xiuqin Lin Fangxiao Liu Xianyang Pang Jinlian Lü Jianwen Li Shixiang Liu Xin |
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| Institution: | Research Institute of Exploration and Development，PetroChina Changqing Oilfield Company，Xian710021，Shaanxi |
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| Abstract: | The sedimentary characteristics of the lower part of the Yanchang Formation(Chang 10-Chang 8 oil bearing intervals)are quite different from the middle and upper parts of the Yanchang Formation(Chang 7-Chang 1 oil bearing intervals). During the deposition of the lower part of the Yanchang Formation，the western and southwestern areas of the basin were characterized by a gentle topography and the deposition was dominated by the braided fluvial，braided fluvial deltaic and coastal shallow lacustrine facies. The content of chemically unstable components was relatively higher in clastic rocks. The depositional framework changed greatly during the deposition of Chang 7 interval of the Yanchang Formation. The sedimentary systems changed to alluvial fan and fan delta in the west and southwest. The size of the downwarping depression increased quickly and semi deep and deep lakes covered an area of over 10×10.4 km2. Simultaneously，the depocenter of the Ordos Basin wasshifted tens of kilometers southwestwards. The component maturity of the clastic rocks increased and the rock combination was obviously different in the west and east dispersal tracts of sediments. Furthermore，analyses of the distribution of the tuffs in the Yanchang Formation indicate that the tuffs are steadily distributed in the basal part of Chang 7 interval of the Yanchang Formation and they were derived from the syn depositional volcanism. Their thickness decreased from the southwest to the northeast. These analyses indicate that the latest depositional period of Chang 8 interval of the Yanchang Formation is an important transitional stage in the basins sedimentary evolution. A strong tectonic movement occurred in the western margin and southwestern margin of the basin and volcanic activities took place frequently. These events represent the first episode of the Indosinian Movement. |
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| Keywords: | Ordos Basin Yanchang Formation sedimentary evolution tuff Early Indosinian Movement |
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