摘要
【目的】鄂尔多斯盆地上石炭统本溪组是加里东运动后的第一套海陆交互相含煤系地层,勘探潜力巨大,但受周缘造山带构造活动影响,盆地东部南北物源体系及多物源复合影响下的盆山耦合关系仍存在争议。进一步示踪物源体系,揭示构造—沉积格局,对盆地东部古地理重建具有十分重要的意义。【方法】通过分析岩屑组分、稀土元素特征和碎屑锆石U-Pb年龄特征,结合构造背景及母岩岩性特征,对鄂尔多斯盆地东部本溪组沉积期源—汇充填过程进行了探讨。【结果】研究区北部的沉积物主要来自主动大陆边缘构造背景下近源的内蒙古隆起(色尔腾山、乌拉山—大青山、集宁地区)和远源的中亚造山带。南部主要接受来自北秦岭的碎屑物质供给,源区构造背景较为复杂,主要为被动大陆边缘和大陆岛弧的混合,其中北秦岭形成沟—弧—盆背景下的拉张伸展向碰撞挤压转换的构造环境。北部源区的母岩岩性为花岗岩、碱性玄武岩和沉积岩的混合,南部源区的母岩岩性主要为花岗岩和碱性玄武岩,且南北物源体系交汇于莲45井—成家沟一带。【结论】本溪期,研究区两侧对应的中亚造山带隆升剥蚀程度较高,反映华北板块北部不规则斜向碰撞的特征。华北板块北缘抬升较高,为研究区北部提供主要物源,以发育大型潮汐—三角洲复合体系为主。受强物源供给影响,研究区东北部砂体延伸距离更远。鄂尔多斯盆地南部以北秦岭为主要源区,华北板块南缘此时低幅隆升,主要发育障壁海岸沉积体系。南北物源交汇区一带,更多地接受来自北秦岭的碎屑物质,同时由于受到东向和北东向潮流作用改造,沉积大量潮汐砂坝。
[Objective]The Upper Carboniferous Benxi Formation in the Ordos Basin is the first set of sea-land inter-action coal-bearing strata after the Caledonian movement and it has great exploration potential,but the coupling rela-tionship between the basin and mountains under the influence of the north-south source system and multi-source com-posite in the eastern part of the basin is still controversial owing to the tectonic activity of the periphery orogenic belt.[Methods]To further trace the source system and restore the paleogeographical pattern,the sedimentary source fill-ing process of the Benxi Formation in the eastern Ordos Basin was discussed by analyzing the characteristics of the rock chip components,rare earth elements,and U-Pb age characteristics of clastic zircon,combined with the tecton-ic background and lithological characteristics of the host rock.[Results]The sediments in the northern part of the study area were derived from the Inner Mongolia uplift(Seltenshan,Wula-Daqingshan,Jining area)and the Central Asian orogenic belt in the active continental margin.The southern part is supplied by clastic material from the North Qinling,and the tectonic background of the source area is relatively complex,which is a mixture of a passive conti-nental margin and continental island arc.In the North Qinling,the tectonic environment includes stretching to colli-sion and extrusion until a trench-arc-basin is formed.The parent rocks in the northern and southern source areas are a mixture of granitic rock and alkaline basalt,and the northern and southern provenance systems converge in the well Lian 45-Chengjiagou area[.Conclusions]Overall,the Central Asian orogenic belt of the Benxi Formation has a high degree of uplift and denudation on both sides of the study area,reflecting the characteristics of irregular oblique colli-sion in the northern North China Plate.The northern margin of the North China Plate has high uplift,which provides the main provenance for the northern part of the study area,and is dominated by the development of a large tide-delta complex system.With a strong source supply,the sand body extends farther in the northeast of the study area.The southern part of the Ordos Basin is the source area of the North Qinling Mountains,and the southern margin of the North China Plate rises at this time,developing the barrier coastal sedimentary system.In the area where the north and south sources meet,more detrital materials from the Northern Qinling Mountains are accepted,and a large num-ber of tidal sand dams are deposited owing to the transformation of the eastward and north-east currents.
作者
张蕊
王琳霖
刘磊
虎建玲
杜佳宁
陈洪德
黄道军
王志伟
朱淑玥
李丹
ZHANG Rui;WANG LinLin;LIU Lei;HU JianLing;DU JiaNing;CHEN HongDe;HUANG DaoJun;WANG ZhiWei;ZHU ShuYue;LI Dan(Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu 610059,China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu 610059,China;Research Institute of Petroleum Exploration and Production,SINOPEC,Beijing 100083,China;Exploration and Development Research Institute of Changqing Oilfield Company,PetroChina,Xi’an 710000,China;National Engineering Laboratory of Low-Permeability Oil&Gas Exploration and Development,Xi’an 710018,China;The 11th Oil Production Plant of Changqing Oilfield Branch of PetroChina,Qingyang,Gansu 745000,China)
出处
《沉积学报》
北大核心
2025年第4期1429-1445,共17页
Acta Sedimentologica Sinica
基金
中石油长庆油田科研项目(2021-18099)
中石化科技部项目(P21088-2)
国家自然科学基金项目(42102132)
中国石油天然气股份有限公司“十四五”基础性前瞻性科技项目(2021DJ2101)。
关键词
古地理格局
碎屑锆石
贡献率
本溪组
鄂尔多斯盆地
paleogeographic pattern
detrital zircon
contribution rate
Benxi Formation
Ordos Basin
作者简介
第一作者:张蕊,女,2001年出生,硕士研究生,地质学,E-mail:zhangrui00106@163.com;通信作者:刘磊,男,研究员,含油气盆地分析,E-mail:liulei@cdut.edu.cn。
