石油与天然气地质 ›› 2024, Vol. 45 ›› Issue (5): 1368-1382.doi: 10.11743/ogg20240512

• 油气地质 • 上一篇    下一篇

川中地区中侏罗世早期天文驱动下的湖平面波动及沉积物分布规律

冯潇飞1,2(), 赵晓明1,2(), 张喜1,2, 葛家旺1,2, 杨长城3, 梁岳立1,2, Bouchakour Massine1,2   

  1. 1.天然气地质四川省重点实验室,四川 成都 610500
    2.西南石油大学 地球科学与技术学院,四川 成都 610500
    3.中国石油 西南油气田公司 气田开发管理部,四川 成都 610056
  • 收稿日期:2024-04-12 修回日期:2024-09-02 出版日期:2024-10-30 发布日期:2024-11-06
  • 通讯作者: 赵晓明 E-mail:fxf0916@163.com;zhxim98@163.com
  • 第一作者简介:冯潇飞(1993—),男,博士研究生,油气开发地质。E-mail:fxf0916@163.com
  • 基金项目:
    国家自然科学基金项目(42072183);国家自然科学青年基金项目(41902124);四川省自然科学基金项目(2023NSFSC0810)

Astronomically forced lake-level fluctuation and sediment distribution patterns during the early Middle Jurassic, central Sichuan Basin

Xiaofei FENG1,2(), Xiaoming ZHAO1,2(), Xi ZHANG1,2, Jiawang GE1,2, Changcheng YANG3, Yueli LIANG1,2, Massine Bouchakour1,2   

  1. 1.Natural Gas Geology Key Laboratory of Sichuan Province,Chengdu,Sichuan 610500,China
    2.School of Geoscience and Technology,Southwest Petroleum University,Chengdu,Sichuan 610500,China
    3.Gas Field Development Management Department,Southwest Oil & Gasfield Company,PetroChina,Chengdu,Sichuan 610056,China
  • Received:2024-04-12 Revised:2024-09-02 Online:2024-10-30 Published:2024-11-06
  • Contact: Xiaoming ZHAO E-mail:fxf0916@163.com;zhxim98@163.com

摘要:

陆相湖盆的湖平面升降导致的盆内沉积充填差异对油气形成与富集具有重要影响,而湖平面波动受气候作用影响明显。选取川中地区中侏罗世早期沙溪庙组一段的湖相连续沉积记录,采用高分辨率自然伽马测井资料作为气候替代指标,开展了中侏罗世早期陆相地层的旋回地层学研究,对长、短偏心率周期进行滤波分析,建立了沙溪庙组一段的浮动天文年代标尺。研究发现:① 沙溪庙组一段陆相湖盆沉积地层中保存了完好的天文旋回响应信号;② 通过川中地区沙溪庙组一段的天文年代标尺计算,认为沙溪庙组一段沉积持续时间约为2.43 Ma;③ 偏心率接近极大值且岁差振幅较大表明气候温暖、潮湿,湖平面相对上升,发育偏泥质沉积,偏心率接近极小值且岁差振幅较小表明气候寒冷、干旱,发育偏砂质沉积,砂质沉积物厚度差异受岁差振幅所调控;④ 中侏罗世早期不同尺度的轨道周期驱动力共同控制了气候的变化,气候变化引起湖平面的波动,湖平面的波动影响了沉积物的分布。

关键词: 湖平面波动, 气候变化, 旋回地层学, 沉积物分布规律, 沙溪庙组一段, 中侏罗世, 陆相湖盆, 四川盆地

Abstract:

The differences in sedimentary filling within a continental lacustrine basin, caused by lake-level fluctuations, pose significant impacts on hydrocarbon generation and enrichment, while the lake-level fluctuations are notably influenced by climatic changes. In this study, we investigate the continuous lacustrine sedimentary records preserved in the 1st member of the Shaximiao Formation (also referred to as the Sha 1 Member) of the early Middle Jurassic in the central Sichuan Basin. Using the high-resolution natural gamma-ray (GR) log data as paleoclimate proxies, we explore the cyclostratigraphy of the early Middle Jurassic continental strata. Through the filtering of long and short eccentricity cycles, we establish a floating astronomical time scale (ATS) for the Sha 1 Member. The results indicate that the sedimentary strata in the lacustrine basin of the Sha 1 Member preserve well-defined response signals to astronomical cycles. Calculations by the ATS reveal that the Sha 1 Member in the central Sichuan Basin underwent continuous deposition for approximately 2.43 Ma. The combination of eccentricity maxima and relatively high precession amplitude suggests a warm and humid climate. In this case, the lake level rose relatively, resulting in the development of argillaceous sediment. In contrast, the combination of eccentricity minima and relatively low precession amplitude implies a cold and arid climate. In this case, sandy sediment occurred, the thickness of which is modulated by precession amplitude. The driving forces of the orbital cycles at different scales during the early Middle Jurassic jointly determined the climatic changes, which caused lake-level fluctuations and further affected the sediment distribution.

Key words: lake-level fluctuation, climatic change, cyclostratigraphy, sediment distribution pattern, the 1st member of the Shaximiao Formation (Sha 1 Member), Middle Jurassic, continental lacustrine basin, Sichuan Basin

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