石油与天然气地质 ›› 2023, Vol. 44 ›› Issue (3): 735-752.doi: 10.11743/ogg20230316

• 油气地质 • 上一篇    下一篇

东海陆架盆地丽水凹陷古新统源-汇系统耦合及时-空演化

朱珍君1(), 李琦1,2, 陈贺贺1,2, 李剑3, 张卫平4, 杨丰繁5, 张迎朝6, 覃军6, 李风勋7, 单帅强7   

  1. 1.中国地质大学(北京) 海洋学院,北京 100083
    2.中国地质大学(北京) 海洋与极地研究中心,北京 100083
    3.中国石化 石油勘探开发研究院,北京 102206
    4.中国石化 新疆新春石油开发有限责任公司,山东 东营 257026
    5.云南省天然气有限公司,云南 昆明 650200
    6.中海石油(中国)有限公司 上海分公司,上海 200335
    7.中国石化 石油勘探开发研究院 无锡石油地质研究所,江苏 无锡 214126
  • 收稿日期:2022-12-05 修回日期:2023-02-23 出版日期:2023-06-01 发布日期:2023-06-05
  • 第一作者简介:朱珍君(1987—),女,博士研究生,海洋地质学、沉积学。E-mail: 3011200003@cugb.edu.cn
  • 基金项目:
    国家重点研发计划项目(2019YFC0605400);国家自然科学基金项目(41576066);教育部产学合作协同育人项目(202102072009);国家自然科学基金重点项目(42230816)

Source-to-sink coupling and temporal-spatial evolution in the Lishui Sag of East China Sea Shelf Basin during the Paleocene

Zhenjun ZHU1(), Qi LI1,2, Hehe CHEN1,2, Jian LI3, Weiping ZHANG4, Fengfan YANG5, Yingzhao ZHANG6, Jun QIN6, Fengxun LI7, Shuaiqiang SHAN7   

  1. 1.School of Ocean Sciences,China University of Geosciences (Beijing),100083,China
    2.Marine and Polar Research Center,China University of Geosciences,Beijing 100083,China
    3.Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 102206,China
    4.Xinjiang Xinchun Petroleum Development Company,SINOPEC,Dongying,Shandong 257026,China
    5.Yunnan Natural Gas Co. ,Ltd. Kunming,Yunnan 650200,China
    6.Shanghai Branch,CNOOC,Shanghai 200335,China
    7.Wuxi Branch of Petroleum Exploration and Production Research Institute,SINOPEC,Wuxi,Jiangsu 214126,China
  • Received:2022-12-05 Revised:2023-02-23 Online:2023-06-01 Published:2023-06-05

摘要:

受构造幕式多期活动和盆内外多物源水系影响,断陷湖盆源-汇系统形成过程复杂,但不同构造阶段的源-汇系统耦合及时-空演化仍处于初步研究阶段。以东海陆架盆地丽水凹陷古新统为例,基于地震、测井、岩心、薄片及重矿物等资料,综合盆地物源体系分析、搬运体系识别与定量追踪、沉积体系刻画及半定量表征,重建了源-汇系统。研究结果表明:断陷早期,盆地多孤立、小型沉积中心,构造活动速率较低,物源供给较少,陡坡带发育较多小规模扇三角洲,缓坡带受先存水系影响,发育小规模辫状河三角洲;断陷强烈期,受灵峰主断裂强烈活动影响,物源供给充足,陡坡带扇三角洲规模增大但数量减少,缓坡带辫状河三角洲规模增大并相互合并;断陷晚期,陡坡带源-汇系统逐渐消亡,缓坡带受全球海平面快速下降影响,河流下切作用增强, 在坡折带下发育大规模盆底扇沉积体系。受构造-沉积格局、母岩类型及边界条件联合控制,丽水凹陷不同构造阶段共发育5种源-汇系统,分别为:①缓坡带北部变质岩为主-SE向U型古沟谷-远源辫状河三角洲;②缓坡带中-南部火山岩为主-NE向断槽/SE向V/U型古沟谷-远源辫状河三角洲/盆底扇;③灵峰凸起北段侵入岩为主-SW向古沟谷-近源扇三角洲;④灵峰凸起中-南段火山岩(早)-变质岩(晚)-SW向古沟谷/NE向断槽-近源扇三角洲;⑤雁荡凸起侵入岩和变质岩-SW/S向古沟谷-近源扇三角洲/辫状河三角洲。物源搬运通道参数半定量统计结果表明,缓坡带古沟谷/断槽宽、浅,陡坡带古沟谷/断槽窄、深;断陷早期和晚期物源搬运通道横截面积与盆内对应沉积体面积具有较好的正相关性。

关键词: 断陷盆地, 源-汇系统, 构造-沉积, 古新统, 丽水凹陷, 东海陆架盆地

Abstract:

The source-to-sink systems in rifted basins are generally complex as a result of multi-stage tectonic activities and multiple provenances and drainage systems both within and outside the basins. The coupling relationship and spatial-temporal evolution of these systems in different tectonic stages are in need of in-depth study. Based on analyses of 3-D seismic data, well logging, cores, thin sections and heavy minerals of the Paleocene Lishui Sag in the East China Sea Shelf Basin, this study attempted to reconstructed the source-to-sink system for the Sag through sediment provenances analyses, transport channels identification and (quantitative) tracing, depositional system mapping and (half-quantitative) characterization. The results show that the early syn-rift stage was characterized by isolated sinks, small depositional centers, low tectonic activity rate, and inadequate sediment supply, with small and numerous fan deltas well-developed in gentle slope zones and small braided river deltas developed in steep slope zones. The main syn-rift stage witnessed sufficient sediment supply, larger but fewer fans developed in steep slopes and the braided river delta enlarged and combined into larger ones in gentle slopes, due to intensive faulting activities. The late syn-rift stage experienced the gradual disappearance of fault-related source-to-sink systems and the development of large floor fans at the slope break zones due to the ever-incrementing river incision as the gentle slope zones were under the influence of rapidly dropping sea level. Under the joint control of tectono-sedimentary pattern, parent rock types and boundary conditions, five source-to-sink systems were developed during different tectonic stages: ① metamorphic rock-dominated parent rocks—SE-trending U-shaped paleo-valley—braided river delta in the northern gentle slope zone, ② volcanic rock-dominated parent rocks—NE-trending faulted-trough /SE-trending V/U-shaped paleo-valley—braided river delta/basin floor fan in the southern gentle slope zone, ③ intrusive rock-dominated parent rocks—SW-trending paleo-valley—fan delta in the northern part of the Lingfeng Uplift, ④ volcanic rock (in early stage)/metamorphic rock (in late stage)—SW-trending paleo-valley/NE-trending faulted-trough—proximal fan delta system in the southern section of Lingfeng Uplift, and ⑤ intrusive and metamorphic rocks—SW/S-trending paleo-valley—fan delta/braided river delta in the Yandang Uplift. Quantitative statistical results of sediment routing systems show that the paleo-valleys and faulted trough in gentle slope zones are wide and shallow, whereas those in the steep slope zones are narrow and deep. The cross-sectional areas of the sediment routings in the early and late syn-rift stages display a positive correlation with the areas of corresponding fan/delta complexes in the Sag.

Key words: rifted basin, source-to-sink system, tectonism-sedimentation, Paleocene, Lishui Sag, East China Sea Shelf Basin

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