鄂尔多斯盆地西部太原组碎屑物质来源与古地理重建
- 1. 成都理工大学沉积地质研究院
- 2. 成都理工大学
基金项目:
其它-中石油长庆油田科研项目(CQYT-CQKTY-2021-JS-2728,2020-62503)
- 收稿日期:
2024-09-26
- 网络出版日期:
2025-03-04
摘要: 【目的】鄂尔多斯盆地二叠系太原组具有厚度大分布广、油气资源类型丰富等特征,展现出巨大的勘探潜力。目前,对该地层的研究主要集中在盆地东部,而西部地区由于构造格局与沉积演化的复杂多变,对太原组的勘探和研究亟待深入探讨。【方法】鉴于此,本研究采用野外露头观察、钻井样品采集,结合前人研究成果,综合运用碎屑锆石U-Pb定年、古流向分析等物源分析方法,对鄂尔多斯盆地西部太原组碎屑物质来源、构造背景及古地理格局进行了系统研究。【结果】研究区东北部(A组)的沉积物主要来自碰撞挤压构造背景下的阴山造山带,物源供给强,向盆地中部依次发育三角洲平原、三角洲前缘、潮汐砂脊和潮汐砂坝。西北部(B组)的沉积物来自于碰撞挤压和汇聚造山构造背景下的阿拉善地块,向盆地中部依次发育三角洲平原、三角洲前缘和潟湖―潮坪。南部(D组)地区的沉积物来自于古特提斯洋扩张―俯冲―碰撞构造环境下的北祁连、北秦岭构造带,太原期中央古隆起变缓,物源供给弱,主要发育障壁岛―障壁―潮坪沉积。【结论】研究区北部在碰撞和汇聚造山构造背景下隆升程度高,物源供给强,发育大型的潮汐―三角洲复合体系,而南部在拉张伸展构造背景下物源供给较弱,以潮坪―潟湖为主。本研究不仅深化了对鄂尔多斯盆地西部沉积体系和物源供给机制的认识,也为重建盆地西部的构造―沉积演化过程和古地理格局提供了新的视角和参考。
Detrital Material Source and Paleogeographic Reconstruction of Taiyuan Formation in Western Ordos Basin
- Received Date:
2024-09-26
- Available Online:
2025-03-04
Abstract: [Objective] The Taiyuan Formation of Permian system in Ordos Basin has the characteristics of large thickness, wide distribution and rich types of oil and gas resources, showing great exploration potential. At present, the study of this formation is mainly concentrated in the eastern part of the basin, while the exploration and study of Taiyuan Formation in the western part of the basin need to be further discussed due to the complex and variable tectonic pattern and sedimentary evolution.[Methods] The detrital material source, tectonic setting and paleogeographic evolution of Taiyuan Formation in western Ordos Basin are systematically studied by means of outcrop observation, drilling sample collection, detrital zircon U-Pb dating and paleo-flow analysis. [Results] The sediments in the northeastern part of the study area (Group A) are mainly from the Yinshan orogenic belt under the collision-compressional tectonic background, with strong provenances. The delta plain, delta front, tidal sand ridge and tidal sand bar are successively developed in the middle of the basin. The sediments in the northwest (Group B) are derived from the Alxa block under the collisional compression and convergent orogenic tectonic background, and the delta plain, delta front and lagoon-tidal flat develop successively towards the middle of the basin. The sediments in the southern (Group D) area came from the North Qilian and North Qinling tectonic belts under the extension-subduction-collision tectonic environment of the Paleo-Tethyan Ocean. The central paleo-uplift of the Taiyuan Period was slow, the provenance-supply was weak, and the mainly developed barrier island-barrier tidal flat deposits. [Conclusions] The northern part of the study area is characterized by high uplift and strong provenance supply in the context of collision and convergence orogenic structures, and large tide-delta complex system, while the southern part is characterized by weak provenance supply in the context of tensile extension structures, and is dominated by tidal flat and lagoon. This study not only deepens the understanding of the sedimentary system and provenance supply mechanism in the western Ordos Basin, but also provides a new perspective and reference for the reconstruction of the tectono-sedimentary evolution process and paleogeographic pattern in the western Ordos Basin.