铝土岩差异性淋滤模式及古环境分析:以鄂尔多斯盆地陇东地区为例  

Analysis of different leaching patterns and paleo-environment of bauxite rocks:A case study of Longdong area,Ordos Basin

作　　者：张涛[1] 张金功[1] 宋世骏 周国晓 Zhang Tao;Zhang Jingong;Song Shijun;Zhou Guoxiao(Department of Geology,Northwest University,Xi'an 710069;Research Institute of Exploration and Development,PetroChina Changqing Oilfield Company,Xi'an 710018)

机构地区：[1]西北大学地质学系,西安710069 [2]中国石油长庆油田分公司勘探开发研究院,西安710018

出　　处：《地质科学》2024年第6期1603-1613,共11页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：中国石油“十四五”前瞻性基础性重大科技项目的外协项目“不同类型致密气成藏机理与富集规律研究”(编号:ZY22-XA705-TPFW727)资助。

摘　　要：为了研究鄂尔多斯盆地铝土岩的淋滤特点,探讨其发育的古环境基础,本文选取陇东地区太原组铝土岩为研究对象,通过镜下薄片观察,进而结合岩性特征,分析了华北板块铝土岩淋滤模式和古环境基础。结果表明,陇东地区铝土质储层经历了地下水的淋滤改造作用,物性得到较大改善;铝土岩的淋滤溶蚀成岩经历了沉积、表生和埋藏3个阶段,在垂向上具有三段式的差异性淋滤溶蚀成岩模式,中部受淋滤改造作用最强;华北板块铝土岩形成的有利因素为温暖热带气候、古隆起斜坡区、古岩溶地貌和海平面交替升降的耦合。因此,鄂尔多斯盆地铝土岩发育古环境良好,在盆地多个地区乃至华北板块均有发现,品质较好的铝土质储层多形成于构造相对高部位,斜坡是有利发育区。In order to study the leaching characteristics of bauxite in Ordos Basin and explore the paleo-environmental basis for its development,this paper selected Taiyuan Formation bauxite in Longdong area as the research object and analyzed the leaching model and paleo-environmental basis of bauxite in North China plate through microscopic observation and combining with the lithology characteristics.The results show that the physical properties of bauxite rock in the study area are greatly improved under the action of underground water leaching.The leaching dissolution diagenesis of bauxite rock has undergone three stages of deposition,supergene and burial,and has a three-stage differential leaching dissolution diagenesis model in the vertical direction,and the central part is most affected by leaching transformation.The favorable factors for the formation of bauxite in North China platform are the coupling of warm tropical climate,paleo-uplift slope area,paleo-karst landform and alternating rise and fall of sea level.Therefore,the bauxite in Ordos Basin has a good paleo-environment and has been found in many parts of the basin as far as the North China plate.The bauxite with good reservoir quality is mostly formed in the relatively high part of the structure,and the slope is a favorable development area.

关 键 词：铝土岩 差异性淋滤溶蚀 古环境 陇东地区 华北板块 鄂尔多斯盆地 

分 类 号：P512.2[天文地球—地质学] P532