重庆市沥鼻峡背斜盐井矿区龙潭组沉积特征及聚煤规律   总被引：1，自引：0，他引：1  

邓光明  曾金源 《中国煤田地质》2007,19(6):5-8

通过对重庆市沥鼻峡背斜盐计矿区含煤地层研究，探讨了矿区龙潭组的沉积特征和聚煤规律，得出矿区龙潭组为泻湖-海湾-潮坪沉积体系，成煤时期的不同沉积环境，聚煤沉降幅度小，沉积速度和物质补偿均衡，有利于泥炭堆积，因此矿区含煤层数、煤层厚度较稳定，该区处于华蓥山潮坪地带，是龙潭期聚煤中心之一。  相似文献   

Zircon U–Pb Ages and Lu–Hf Isotope of the Dongchuan Group in Central Yunnan, China, and their Geological Significance     

HAN Kunying  ZHANG Heng  DING Xiaozhong  REN Liudong  SHI Chenglong  PANG Jianfeng 《《地质学报》英文版》2020,94(4):1093-1116

On the southwestern margin of the Yangtze Block, the Dongchuan Group consists of slightly metamorphosed sedimentary rocks, including silty slate, argillaceous slate, clayey slate, arkose, dolomite, and minor volcanic rocks. To date, it is still a controversy over the depositional age and stratigraphic sequence of the Dongchuan Group. In this study, we analyzed five samples of meta-sedimentary rocks and one sample of meta-tuff from the Yinmin, Luoxue and Etouchang Formations of the Dongchuan Group in the Yuxi region for detrital zircon U-Pb ages and Lu-Hf isotope. The detrital zircon ages of the meta-sediments vary from 3073 to 1703 Ma, mainly clustered at three periods, from 1889 to 1840, 2490 to 2008 and 2878 to 2844 Ma. The youngest age peak of all the samples is ～1859 Ma, with the εHf(t) values of the zircons ranging from-20.3 to +4.3 and more than 90% being negative, indicating that the Paleoproterozoic crustal accretion on the southwestern margin of the Yangtze Block was dominated by reworking of the ancient crustal materials involved in the assembly and breakup of the Columbia supercontinent. Another important age range is between 2490 Ma and 2008 Ma, with εHf(t) values from-14.7 to +8.9 and 70% of them are negative, suggesting that the magmatism in the source area was also dominated by reworking and recycling of the ancient crustal materials, with minor juvenile mantle substances added. The detritus was probably derived from the Paleoproterozoic crystalline basement in the southern Yuxi region. The oldest peak age is ～2847 Ma and the εHf(t) values are from-7.7 to +7.0 with 50% of both positive and negative values, demonstrating a possible ～2.85 Ga ancient continental nucleus on the southwestern margin of the Yangtze Block and substantial growth in juvenile crust materials during this period. Besides, the weighted average age of the zircons from the meta-tuff of the Etouchang Formation is 1677 ± 14 Ma. Combining the previous research data and this study, we can constrain the depositional age of the Dongchuan Group in central Yunnan Province to the period from the late Paleoproterozoic to early Mesoproterozoic, slightly earlier than that of the Dongchuan Group in the Dongchuan area near to the southwestern Sichuan Province. The depositional age of the Dongchuan Group is older than that of the Kunyang Group.  相似文献   

硅质岩沉积地球化学研究现状   总被引：5，自引：0，他引：5  

盛吉虎  陈中新 《地域研究与开发》1998,(Z1)

硅质岩是造山带中分布最为广泛的岩石类型之一,硅质岩沉积环境的确定对深海沉积作用、大陆边缘地质学及大地构造格架的厘定具有重要意义。目前,在硅质岩沉积地球化学研究方面有以下主要进展：①硅质岩沉积地球化学研究;②与蛇绿岩有关的硅质岩沉积地球化学研究;③物质来源研究;④古氧化还原条件研究;⑤硅质岩构造环境判别  相似文献   

扇三角洲沉积体系及其与油气聚集关系   总被引：23，自引：2，他引：21  

焦养泉  周海民 《沉积学报》1998,16(1):70-75

扇三角洲沉积体系是断陷盆地中极为发育的一种沉积体系,主要由扇三角洲平原组合、扇三角洲前缘组合和前三角洲沉积构成,可识别出9种成因相。受沉积物供给速率、可容空间增长速率及盆缘断裂产状等因素控制可划分出退积型、加积型、前积型、陡坡型和缓坡型5种扇三角洲类型。位于扇三角洲平原的辫状分流河道砂体及其位于扇三角洲前缘的与之有成因联系的水下分流河口坝、洪水型重力流砂体等物性好,可以构成优质储层。含油性勘探成果亦证实各主力油层段平面上主要分布于扇三角洲前缘及分流间湾区,小部分位于扇三角洲平原区。受埋藏深度和成岩场的影响,不同地区、不同层位主力油层段的物性与岩性相关性各异。因此,应用沉积体系分布与油气聚集规律挖掘剩余油层及进行远景区预测是有效的与可行的。  相似文献   

吐鲁番-哈密盆地南缘保罗系层序地层特征及成铀规律     

董文明  黄贤芳  谢志东  潘蔚 《铀矿地质》1998,(3)

本文运用层序地层学理论和工作方法,对吐鲁番-哈密盆地南缘诛罗系地层进行了详细研究,识别出3个Ｉ类层序,分别与岩石地层单位八道湾组、三工河组、西山窑组大致相当;在层序体系域、沉积体系研究的基础上,指出层序内高水位体系域（HST）中的辫状河三角洲体系是层间氧化带砂岩型铀矿产出的有利层位。  相似文献   

西北侏罗纪盆地沉积层序演化与储层特征   总被引：9，自引：3，他引：6  

吴因业  罗平 《地质论评》1998,44(1):90-99

笔者研究了西北侏罗纪盆地沉积层序及储层特征,根据露头观察,井下实钻资料及实验室内分析结果,提出中,下侏罗统主要为湖沼相含煤碎屑岩沉积,主要发育河流中冲积相及三角洲相的砂岩集集体,上统为红色或杂色碎屑岩,侏罗纪计导氏孔低渗为主的富含火山岩屑的碎屑岩,局部可发育较好砂岩储层,侏罗系本身可构成妨好的生储盖组合。  相似文献   

南京汤山膨润土矿地质特征,物化性质及矿床成因   总被引：3，自引：0，他引：3  

陈淑祥  陈克荣 《高校地质学报》1998,4(3):279-285

通过对南京近郊汤山膨润土矿床的矿区地质、矿床地质特征的分析,阐明了该矿床的成因及其矿石的物化性能。综合研究表明,该矿床是以流纹岩及凝灰岩为成矿原岩,在特定的条件下,经热液蚀变改造而形成的矿床。此矿床之矿石属钙基膨润土,经适当选矿后可用于深加工。  相似文献   

西沙海槽沉积模式   总被引：1，自引：0，他引：1  

熊斌辉  刘春成  郭瑞 《海洋地质译丛》2009,(4):1-9

晚中新世琼东南盆地快速构造沉降，沉积欠补偿形成了西沙海槽。西沙海槽上部高陡带为悬浮沉积体系，下部低缓带为浊流滑塌沉积体系，槽底平缓带为河流沉积体系。不同于浊流沉积小而散，深海河流沉积为稳定的贯穿整个海槽的大储层。由于深海河流沉积体系稳、远、大的特点，其注定成为世界深水油气勘探的主要目标。  相似文献   

珠江口盆地白云凹陷陆坡区10.5 Ma以来的沉积体系   总被引：1，自引：0，他引：1  

武强  解习农  邱燕  刘明玲 《海洋地质与第四纪地质》2008,28(2):1-6

通过对珠江口盆地白云凹陷陆坡区10.5Ma以来的地震相分析,共识别出席状平行亚平行地震相、透镜状前积地震相、深切河谷地震相、帚状地震相和杂乱地震相,不同的地震相分别代表不同的沉积体系类型。综合所识别的地震相类型,分析了陆架边缘下切谷、浊积扇和陆架边缘三角洲3种主要的沉积体系及其配置关系。物源供给是影响陆坡区沉积体系发育的最重要因素,是沉积体系发育的物质基础,海平面变化和构造运动为沉积体系发育提供了可容纳空间,3种影响因素共同影响了陆坡区沉积体系的发育。  相似文献   

Provenance of deep-water reservoir sandstones from the Jubarte oil field,Campos Basin,Eastern Brazilian Margin     

Paola De Rossi Fontanelli  Luiz Fernando De Ros  Marcus Vinicius Dorneles Remus 《Marine and Petroleum Geology》2009

The provenance of the Maastrichtian deep-water reservoir sandstones from the Jubarte oil field (Campos Basin, eastern Brazil), was studied using an integrated approach that included quantitative petrography, conventional heavy mineral analysis, garnet mineral chemistry and zircon geochronology. The reservoirs are predominantly coarse, poorly-sorted sandstones with feldspathic composition derived from uplifted basement terrains. The fourth- and fifth-order depositional sequences analyzed show no major variations in composition or in provenance through time. However, variations in apatite:tourmaline presents potential to be used as a parameter for sandstone correlation within the field. The composition of heavy minerals indicates derivation from high temperature and low-to-medium pressure aluminous metapelitic rocks, from granites and subordinate mafic rocks, derived from the Cabo Frio Tectonic Domain and the Oriental terrain of Ribeira orogen, characterizing a supply route from SW to NE. The low ZTR index, as well as the absence of low-grade stable heavy minerals and of metasedimentary rock fragments, suggest that by the end of Cretaceous all supracrustal, low-grade terrains had already been totally eroded, and that plutonic, infracrustal rocks were exposed, similarly to the present situation.  相似文献