鄂尔多斯盆地东北部上古生界不同细粒岩微量元素地球化学特征及地质意义  

Trace element geochemistry of different fine-grained rocks of Upper Paleozoic in the northeastern Ordos Basin and the geological significance

作　　者：马乾[1] 孟令箭[1] 王建伟[1] 赵俊兴[2] 张永超[1] 赫逍瑶 魏思远 彭帅杰 魏炜 MA Qian;MENG Lingjian;WANG Jianwei;ZHAO Junxing;ZHANG Yongchao;HAO Xiaoyao;WEI Siyuan;PENG Shuaijie;WEI Wei(Petrochina Jidong Oilfield Branch,Tangshan,Hebei 063000,China;Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu,Sichuan 610059,China;Xi’an Shiwen Software Co.Ltd.,Xi’an,Shaanxi710000,China)

机构地区：[1]中国石油冀东油田分公司,河北唐山063000 [2]成都理工大学沉积地质研究院,四川成都610059 [3]西安石文软件有限公司,陕西西安710000

出　　处：《矿物岩石》2024年第4期30-40,共11页Mineralogy and Petrology

摘　　要：沉积环境研究在油气勘探中具有重要意义,鄂尔多斯盆地东北部晚古生代沉积环境复杂多变,本次研究通过70件不同细粒岩微量元素测试分析,优选了对古沉积环境敏感的元素及参数组合,研究了盆地东北部晚古生代沉积期盐度、古氧化还原环境,气候纵横向上的变化特征,以此来对研究区的沉积环境进行恢复。结果表明:①Ba、Sr及Sr/Ba值显示从本溪期到石千峰期,盐度呈明显的波动降低趋势,沉积环境从海相咸水向陆相淡水环境波动式变化。盐度从南向北逐渐降低,由海相向陆相过渡;②Cu/Zn、Ni/Co、V/(V+Ni)值显示从本溪期到石盒子期的沉积水体含氧量增高,由贫氧的还原环境过渡到氧化环境;③煤岩中具有富集元素Be、Sr趋势,灰岩中具有富集元素Zn趋势,泥岩中具有富集元素Li、V、Cr、Mn、Co、Ni、Cu、Cd、Sb、Ba趋势,铝土岩中具有富集元素Li、Cr、Zr、Ga、Sn趋势。同一层位、同一岩性微量元素含量分布相对稳定;④本溪组至石盒子组发育海相与湖泊两大类型三角洲成因砂体,是致密砂岩储层有利成因类型。建议在全国建立细粒岩微量元素测试标样,以提高微量元素测试精度。With the advancement of modern sedimentology,the reconstruction of sedimentary facies and environments has evolved from traditional qualitative methods-such as analyzing rock color,sedimentary structures,rock textures,and paleontological evidence-to more comprehensive approaches that incorporate semi-quantitative and quantitative techniques.Trace elements in rocks and their associated parameters have gained widespread application due to their ability to facilitate the semi-quantitative and quantitative reconstruction of paleo-sedimentary environments.In this study,trace elements in 70 various fine-grained rocks were analyzed to refine the selection of elements and parameters sensitive to paleo-sedimentary con-ditions.The research focuses on salinity,paleoredox conditions,and climatic characteristics during the Late Paleozoic in the northeastern Ordos Basin,aiming to reconstruct the sedimentary environment of the re-gion.The results reveal the following:l.Ba,Sr,and Sr/Ba values exhibit significant fluctuations and a gen-eral decline in salinity from the Benxi to the Shiqianfeng periods.This trend reflects a shift in the sedimen-tary environment from marine saline water to a continental freshwater setting,with salinity decreasing progressively from south to north,marking the transition from marine to terrestrial conditions.2.Ratios such as Cu/Zn,Ni/Co,and V/(V+Ni)indicate a gradual increase in oxygen levels in the sedimentary wa-ters from the Benxi to the Shiqianfeng periods.This suggests a transition from an oxygen-poor,reducing environment to an oxidizing one.3.Distinct enrichment trends are observed for trace elements across dif-ferent rock types.Be and Sr are enriched in coal rocks;Zn in limestone;Li,V,Cr,Mn,Co,Ni,Cu,Cd,Sb,and Ba in mudstone;and Li,Cr,Zr,Ga,and Sn in bauxite.Within the same stratigraphic horizon and lithology,the trace element content remains relatively stable.4.From the Benxi Formation to the Shihezi Formation,two types of deltaic sand bodies-marine and lacustrine-developed,representing promis

关 键 词：微量元素 古环境 上古生界 鄂尔多斯盆地 东北部 测试标样 

分 类 号：P595[天文地球—地球化学]