| 涠西南凹陷陡坡带流一段上亚段异重流沉积新发现 |
| |
| 引用本文： | 金杰华,操应长,王健,杨田,刘娟,王心怿,王淑萍.涠西南凹陷陡坡带流一段上亚段异重流沉积新发现[J].地学前缘,2019,26(4):250-258. |
| |
| 作者姓名： | 金杰华 操应长 王健 杨田 刘娟 王心怿 王淑萍 |
| |
| 作者单位： | 中国石油大学(华东)地球科学与技术学院,山东青岛266580;中国石油大学(华东)地球科学与技术学院,山东青岛266580;青岛海洋科学与技术国家重点实验室海洋矿产资源评价与探测技术功能实验室,山东青岛266071;中海石油(中国)有限公司湛江分公司,广东湛江524057 |
| |
| 基金项目： | 中国科学院战略型先导科技专项(A类)子课题(XDA14010301)；国家自然科学基金项目(U1762217)；国家科技重大专项专题(2017ZX05009001)；中央高校基本科研业务费专项资金项目(16CX06036A，18CX05027A)；中国博士后科学基金面上项目(2017M622314) |
| |
| 摘 要： | 以涠西南凹陷北部陡坡带中段流一段下亚段为研究对象，综合利用三维地震、测井、录井、钻井岩心及分析测试等资料，对研究区异重流成因深水扇的沉积特征、控制因素及沉积模式进行了研究。结果表明，断陷盆地陡坡带至湖盆底部可发育洪水型异重流沉积，依次为顺直水道、弯曲水道和朵叶体，其延伸距离约为15 km，宽度为50~150 m。其中，水道地震反射明显强于周围深水泥岩，其内部沉积以砂岩和含砾砂岩为主；朵叶体沉积主要为细砂岩或粉砂岩，富含陆源植物碎屑，其粒度概率曲线以上拱弧式及宽缓上拱式为主，样品点分布大致平行于C=M基线，指示重力流沉积动力特征。垂向上，单层砂岩一般表现为逆粒序与正粒序成对出现，中部粒度最粗，可见泥质碎屑呈叠瓦状排列，且发育层内微侵蚀面。此外，异重流沉积内部发育块状层理、平行层理、波状交错层理及爬升砂纹层理等沉积构造。“源汇”系统决定了异重流的沉积特征与展布，万山隆起东部岩浆岩等物源输入是异重流形成的物质基础，强构造运动、陡坡折带、湿润半湿润气候及低湖水密度是控制异重流发育程度的主要因素。研究区异重流的发现不仅丰富了断陷湖盆陡坡带沉积相类型，也为陡坡带进一步油气勘探提供了理论依据。
|
| 关 键 词： | 异重流沉积 沉积特征 控制因素 陡坡带 流一段下亚段 涠西南凹陷 |
| 收稿时间： | 2018-06-14 |
New discovery of hyperpycnal flow deposits in the Elx1 section of the steep slope belt in the Weixinan sag |
| |
| JIN Jiehua,CAO Yingchang,WANG Jian,YANG Tian,LIU Juan,WANG Xinyi,WANG Shuping.New discovery of hyperpycnal flow deposits in the Elx1 section of the steep slope belt in the Weixinan sag[J].Earth Science Frontiers,2019,26(4):250-258. |
| |
| Authors: | JIN Jiehua CAO Yingchang WANG Jian YANG Tian LIU Juan WANG Xinyi WANG Shuping |
| |
| Abstract: | In a case study in the lower part of the first member of the Liushagang Formation (Elx1) in the middle of the steep slope zone in the Weixinan sag, we examined the sedimentary characteristics, controlling factors and distribution features of deep-water fan formed by hyperpycnal flow through analyzes of 3D seismic information, well logging and core drilling data and laboratory measurements. The results show that hyperpycnites are distributed from the steep slope to the bottom of lacustrine basin, where hyperpycnal flow developed sequentially straight and meandering channels and lobes which expand 15 km long and 50100 m wide. The seismic reflections of hyperpycnites are obviously stronger than that of the surrounding deep-water mudstones. Hyperpycnites are mainly composed of fine-grained sandstone, siltstone and small amounts of pebbly sandstone; terrigenous biolastics (plant material) are also common. The grain size accumulation curve is mainly overarching and the sample point distribution is roughly parallel to the baseline of C=M, showing the characteristics of gravity flow deposits. A bed of sandstone is usually composed of paired inverse and normal grading sequences, with the coarsest grain depositing in the middle of the bed. Rip-up mud clasts are typical with imbrication. The intrasequence weak erosional contacts are also obvious. In addition, hyperpycnal flow developed sedimentary structures of massive and parallel bedding, Hummocky cross-stratification and climbing sand ripples by bed- and suspended-load transportation. Since sedimentary characteristics and distribution of hyperpycnites are determined by source-to-sink system, magmatic rocks originated from eastern Wanshan uplift provided the material basis of hyperpycnites, while strong tectonic movements, steep slope, wet-half humid climate and relatively low density of water are the main controlling factors for the development of hyperpycnites. Our discovery of hyperpycnal flow deposits in the study area not only enriches our knowledge of sedimentary environment in the steep slope belt in lacustrine basin, but also provides theoretical guidance for further hydrocarbon exploration in steep slope regions. |
| |
| Keywords: | hyperpycnites sedimentary characteristics controlling factors steep slope lower part of the first member of the Liushagang Formation Weixinan sag |
| 本文献已被 万方数据 等数据库收录！ |
| 点击此处可从《地学前缘》浏览原始摘要信息 |
| 点击此处可从《地学前缘》下载免费的PDF全文 |
|
