鄂尔多斯东北部中侏罗世孢粉化石及古气候意义  

Sporopollen assemblage from the Middle Jurassic of the northeastern Ordos basin, Inner Mongolia, and their paleoclimatic implications

作　　者：黄磊[1,2] 张晓晶 李钢柱[1,2] 季兴开 韩萱 王振义 刘志强 侯泽明 艾子涵 Huang Lei;Zhang Xiaojing;Li Gangzhu;Ji Xingkai;Han Xuan;Wang Zhenyi;Liu Zhiqiang;Hou Zeming;Ai Zihan(Water Conservancy and Civil Engineering College,Inner Mongolia Agricultural University,Inner Mongolia Key Laboratory of Water Resource Protection and Utilization,Hohhot,Inner Mongolia 010018,China;Autonomous Region Collaborative Innovation Center for Integrated Management of Water Resources andWater Environment in the Inner Mongolia Reaches of the Yellow River,Hohhot,Inner Mongolia 010018,China;Nanjing Institute of Geology and Palaeontology,Chinese Academy of Sciences,Nanjing,Jiangsu 210008,China;Institute of Geology,Chinese Academy of Geological Sciences,Beijing 100037,China)

机构地区：[1]内蒙古农业大学水利与土木建筑工程学院,内蒙古自治区水资源保护与利用重点实验室,内蒙古呼和浩特010018 [2]黄河流域内蒙段水资源与水环境综合治理自治区协同创新中心,内蒙古呼和浩特010018 [3]中国科学院南京地质古生物研究所,江苏南京210008 [4]中国地质科学院地质研究所,北京100037

出　　处：《地质学报》2023年第5期1390-1406,共17页Acta Geologica Sinica

基　　金：内蒙古自治区科技计划项目(编号2020GG0076);内蒙古自然科学基金项目(编号2021MS04024,2021BS04007,2021MS04013);国家自然科学基金项目(编号51969023,42262010);内蒙古自治区高等学校科学技术研究项目(编号NJZZ19042)联合资助的成果。

摘　　要：鄂尔多斯盆地东北部内蒙古伊金霍洛旗乌兰木伦地区是我国重要的能源矿产地,含煤岩系赋存在侏罗系延安组中,延安组岩石组合以灰白色砂岩、灰色粉砂岩、灰色泥岩为主,夹多层煤层;延安组上覆直罗组以灰色、灰绿色砂岩、灰色粉砂岩、紫红色泥岩为主。通过对乌兰木伦地区武家塔露天煤矿剖面延安组和直罗组孢粉化石分析,在延安组中识别出Cyathidites-Lycopodiumsporites-Neoraistrickia-Cycadopites孢粉组合带,以桫椤科、石松科孢子繁盛,紫萁科孢子和单沟/原始沟类、松柏类两气囊花粉发育,卷柏科孢子及柏科花粉较常见为主要特征,时代为中侏罗世早期(阿林期—巴柔期)。根据延安组孢粉母体植物的生态环境分析,本区在这一沉积时期的气候属于温暖湿润的亚热带—温带型气候。直罗组孢粉化石较少,主要见Cyathidites minor,Osmundacidites parvus,Concentrisporites fragilis,Cycadopites spp.等。综合地层岩性、孢粉组合及古植被分析,延安组到直罗组沉积时期总体上呈现从温暖湿润的亚热带—温带型向半干旱—干旱炎热型的气候变化过程。The Wulanmulun area in Ejin Horo Banner,Inner Mongolia,which is located in the northeast of Ordos basin,is an important energy base in China.The Jurassic Yan'an Formation is the most important coal-bearing strata in the area.The rock assemblage is mainly gray-white sandstone,gray siltstone,gray mudstone,and multilayer coal seams.The Yan'an Formation is overlain by Zhiluo Formation.The rock assemblage of Zhiluo Formation is mainly gray,gray-green sandstone,gray siltstone and purplish red mudstone.Based on the analysis of sporopollen fossils of Yan'an Formation and Zhiluo Formation in the profile of Wujiata coalmine in Wulanmulun area,the sporopollen assemblage zone ofCyathidites-Lycopodiumsporites-Neoraistrickia-Cycadopitesis identified in the Yan'an Formation.In this assemblage,Cyatheaceae and Lycopodiaceae spores are abundant,Osmundaceae spores,Monocolpates/Praecolpates and coniferous Disaccate pollen are developed,and Selaginellaceae spores and Cupressaceae pollen are common.This indicates that the age of Yan'an Formation is the early Middle Jurassic(Aalenian-Bajocian period).The palynological record confirms that a warm and humid subtropical/temperate climate in the Wulanmulun area during the Yan'an Formation deposition period.There are few sporopollen fossils found in Zhiluo Formation which mainly includeCyathidites minor,Osmundacidites parvus,Concentrisporites fragilis,Cycadopitesspp,etc.Based on the analysis of stratigraphic lithology,sporopollen assemblage and palaeovegetation,the sedimentary period from Yan'an Formation to Zhiluo Formation generally presented a climate change process from warm and humid subtropical/temperate type to semi-arid/arid and hot type.

关 键 词：孢粉 中侏罗世 延安组 直罗组 古气候 鄂尔多斯盆地 

分 类 号：P534.52[天文地球—古生物学与地层学] P532[天文地球—地质学]