摘要
鄂尔多斯盆地西南部下白垩统铀矿找矿在近几年取得了重大突破,在镇原、彭阳等地区发现了新的铀矿产地,白垩系铀矿化主要赋存于洛河组与环河组,少部分赋存于泾川组和罗汉洞组,这些赋矿层位原生沉积均处在干旱环境条件下,其中缺乏肉眼可见的有机质。但在钻孔岩心中,铀矿化砂岩中往往富含浸染状的有机质,这类有机质的性质及其与铀成矿的关系目前还缺乏系统的研究。文章以鄂尔多斯盆地西南部镇原地区铀矿化砂岩为研究对象,通过岩心观察与室内研究,厘定了赋矿砂岩中的有机质类型,探讨了有机质的来源及其铀成矿的关系。研究结果表明:赋矿砂岩中的原生沉积炭屑有机质十分稀少,有机质主要为充填于砂岩微孔隙中、具有流动特征、低演化程度的大分子有机质,可能主要来源于“延7”段烃源岩。铀矿化与固体炭屑有机质关系不大,而主要与“可溶性”流动状有机质密切相关。研究区白垩系铀成矿特征具有“渗出”砂岩型铀矿成矿作用的特点。
In recent years,a great breakthrough has been made in the uranium prospecting in the Lower Cretaceous in southwestern Ordos Basin.New uranium deposits have been discovered in some districts of Zhenyuan and Pengyang county.The uranium mineralization in Cretaceous sandstones mainly occurs in the Luohe and Huanhe Formations,a few uranium mineralization occurs in the Jingchuan Formation and Luohandong Formation.The primary sediments of these ore-bearing strata are all formed in arid environment,and lack of visible organic matter.However,the mineralization rocks are rich in disseminated organic matter in the drill cores,but few systematic study was reported on the properties of disseminated organic matter and its relationship with uranium mineralization.In this paper,the types of organic matter in the uranium-bearing sandstone was found determined based on the core observations and laboratory study.The results show that the organic matter from the original sediments in the U-bearing sandstone is very rare,and the organic matter is mainly the macromolecular organic matter filled in the micro-pores of the sandstone with the characteristics of flow and low evolution degree,the source rock of 7th member of Yanchang Formation may be the main source rock.The uranium mineralization is not related to the organic matter as solid carbon debris,but mainly to the“soluble”and“flowing”organic matter.The characteristics of Cretaceous uranium mineralization in the study area are correspond to the exudative uranium metallogeny of sandstone type U-mineralization.
作者
邱林飞
李子颖
贺锋
武正乾
刘坤鹏
毛宁
李孟华
QIU Linfei;LI Ziying;HE Feng;WU Zhengqian;LIU Kunpeng;MAO Ning;LI Menghua(CNNC Key Laboratory of Uranium Resources Exploration and Evaluation Technology,Beijing Research Institute of Uranium Geology,Beijing 100029,China;Research Institute No.203,CNNC,Xi’an,Shaanxi 710086,China;East China University of Technology,Nanchang,Jiangxi 330013,China)
出处
《铀矿地质》
CSCD
2024年第1期41-56,共16页
Uranium Geology
基金
中核集团集中研发项目(编号:中核科发2021-143号)
国家重点基金项目(编号:U2167210)
中核集团青年英才项目(编号:地QNYC2301)
中国核工业地质局地勘费项目(编号:202115-2)联合资助。
关键词
流动状有机质
风成砂
下白垩统
砂岩型铀矿
鄂尔多斯盆地
mobile organic matter
aeolian sandstone
Lower Cretaceous
sandstone-type uranium deposit
Ordos Basin
