| 冀中坳陷饶阳凹陷蠡县斜坡古近系沙河街组一段浅水三角洲和滩坝的沉积环境* |
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| 引用本文： | 叶蕾,朱筱敏,张锐锋,谢爽慧,高园,唐宏,齐雪竹,陈亚青.冀中坳陷饶阳凹陷蠡县斜坡古近系沙河街组一段浅水三角洲和滩坝的沉积环境*[J].古地理学报,2020,22(3):587-600. |
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| 作者姓名： | 叶蕾 朱筱敏 张锐锋 谢爽慧 高园 唐宏 齐雪竹 陈亚青 |
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| 作者单位： | 1.中国石油大学(北京)地球科学学院,北京 102249;2.中国石油华北油田分公司,河北任丘 062552 |
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| 基金项目： | *国家重大科技专项(编号: 2017ZX05001-002-002)资助 |
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| 摘 要： | 浅水三角洲和滩坝不仅是当今沉积学研究热点,也是油气勘探重要的沉积类型,沉积环境控制着浅水三角洲和滩坝沉积体系的发育及演化。基于岩心、钻井、测井数据及孢粉化石、微量元素等分析化验资料,对渤海湾盆地冀中坳陷饶阳凹陷蠡县斜坡古近系沙河街组一段(简称“沙一段”)的沉积体系类型及沉积环境进行了综合研究。研究表明: (1)沙一段主要发育浅水三角洲和滩坝沉积。其中,沙一下亚段尾砂岩沉积时,以浅水三角洲内前缘、外前缘沉积为主;沙一下亚段特殊岩性段沉积时,湖平面上升,浅水三角洲退积,以滨浅湖滩坝为主;沙一上亚段沉积时,湖平面下降,三角洲向湖盆中心持续推进,沉积主体转变为浅水三角洲。(2)浅水三角洲和滩坝的沉积演化受控于沉积环境。沙一下亚段尾砂岩沉积时,处于较为干旱的亚热带气候,沉积水体较浅,为微咸水—半咸水的氧化环境,有利于浅水三角洲的发育;沙一下亚段特殊岩性段沉积时,发生大规模湖侵,水体加深,物源供给少,气候相对湿润,且盐度增加,过渡为还原环境,有利于滨浅湖滩坝的形成;沙一上亚段沉积时,物源供给充足,整体处于相对湿润的温带、亚热带气候,湖盆收缩,水体变浅,盐度相对较低,处于氧化条件下的淡水环境,有利于浅水三角洲的沉积。
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| 关 键 词： | 浅水三角洲 滩坝 沉积特征 沉积环境 沙河街组 饶阳凹陷 冀中坳陷 |
| 收稿时间： | 2020-03-09 |
Sedimentary environment of shallow-water delta and beach-bar of the Member 1 of Shahejie Formation in Lixian slope of Raoyang sag,Jizhong Depression |
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| Ye Lei,Zhu Xiao-Min,Zhang Rui-Feng,Xie Shuang-Hui,Gao Yuan,Tang Hong,Qi Xue-Zhu,Chen Ya-Qing.Sedimentary environment of shallow-water delta and beach-bar of the Member 1 of Shahejie Formation in Lixian slope of Raoyang sag,Jizhong Depression[J].Journal of Palaeogeography,2020,22(3):587-600. |
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| Authors: | Ye Lei Zhu Xiao-Min Zhang Rui-Feng Xie Shuang-Hui Gao Yuan Tang Hong Qi Xue-Zhu Chen Ya-Qing |
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| Institution: | 1.College of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China;2.PetroChina Huabei Oilfield Company,Hebei Renqiu 062552,China |
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| Abstract: | Shallow-water delta and beach-bar are not only the current research hotspots of sedimentology,but also the important sedimentary types of sand body for oil and gas exploration. The sedimentary environment controls the development and evolution of shallow-water delta and beach-bar. Based on the analysis of core,well,logging,spore-pollen fossils and trace elements,the types of sedimentary system and sedimentary environment of the Member 1 of Paleogene Shahejie Formation in the Lixian slope of the Raoyang sag,Jizhong Depression was studied integratedly. The results showed that: (1)Shallow-water delta and beach-bar deposits were mainly developed in the study area in the Member 1 of Shahejie Formation(Es1). The inner and outer shallow-water delta fronts predominated during the deposition of the bottom sandstone section of the lower sub-Member of Es1. Lake level rose and shallow-water delta retrograded,and beach-bar predominated during the deposition of the special lithologic section of the lower sub-Member of Es1. The lake level fell,and the delta that prograded to the center of lake. The main sedimentary body changed into the shallow-water delta during the deposition of the upper sub-Member of Es1. (2)The sedimentary evolution of shallow-water delta and beach-bar are controlled by sedimentary environment. During the deposition of the bottom sandstone section of the lower sub-Member of Es1,the study area was in a relatively arid subtropical climate,and the lake was in the relatively shallow oxidized and brackish setting,which was conducive for the development of the shallow-water delta. During the deposition of the special lithologic section of the lower sub-Member of Es1,large-scale lake transgression increased the lake level,while the provenance supply was limited in the study area. The lake changed into the reducing setting within the relatively humid climate and increased salinity,which was favorable for the formation of beach-bar. During the deposition of the upper sub-Member of Es1,the source supply was sufficient,and the study area was in the relatively humid subtropical climate. Meanwhile,the lake basin shrank,the lake level decreased. The relatively low salinity and oxidized fresh water setting was conductive for the deposition of the shallow-water delta. |
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| Keywords: | shallow-water delta beach-bar sedimentary characteristics sedimentary environment Shahejie Formation Raoyang sag Jizhong Depression |
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