Palynological Assemblage Age and Palaeoenvironment of the Cretaceous Salt-bearing Strata in Laos and Yunnan,China     

YUAN Qin  LI Jianguo  QIN Zhanjie  WEI Haicheng  SHENG Shurong  SHAN Fashou 《《地质学报》英文版》2014,88(Z1):276-276

正The study of Cretaceous-Palaeogene salt-bearing strata of the Khorat Basin Laos and the Lanping-Simao Basin in Yunnan,China has an great significance not only in explaining the basin evolution and the genesis of potash  相似文献   

Clay Mineralogical and Geochemical Studies of Detrital Rocks of the Upper Cretaceous Salt-bearing Strata,Simao Basin,SW China:Implication for Provenance and Source Weathering     

MIAO Weiliang  MA Haizhou  ZHANG Xiying  LI Yongshou  SHI Haiyan 《《地质学报》英文版》2014,88(Z1):235-237

正1 Introduction Geological studies established on several sections in Lanping-Simao basin have shown that the salt-bearing strata of Mengyejing formation(Yunlong Fm.in Lanping basin)are constituted by an alternation of salt layers and interbedded facies.The latter consists mainly of mudstones,and mudstone-rich conglomerate.The mineralogy and geochemistry of salt-bearing beds and  相似文献   

Relationships between major and trace elements during weathering processes in a sedimentary context: Implications for the nature of source rocks in Douala,Littoral Cameroon     

《Chemie der Erde / Geochemistry》2014,74(4):765-781

In Douala (Littoral Cameroon), the Cretaceous to Quaternary formation composed of marine to continental sediments are covered by ferrallitic soils. These sediments and soils have high contents of SiO₂ (≥70.0 wt%), intermediate contents of Al₂O₃ (11.6–28.4 wt%), Fe₂O₃ (0.00–20.5 wt%) and TiO₂ (0.04–4.08 wt%), while K₂O (≤0.18 wt%), Na₂O (≤0.04 wt%), MgO (≤0.14 wt%) and CaO (≤0.02 wt%) are very low to extremely low. Apart from silica, major oxides and trace elements (REE included) are more concentrated in the fine fraction (<62.5 μm) whose proportions of phyllosilicates and heavy minerals are significant. The close co-associations between Zr, Hf, Th and ∑REE in this fraction suggest that REE distribution is controlled by monazite and zircon. CIA values indicate intense weathering. Weathering products are characterized by the association Al₂O₃ and Ga in kaolinite; the strong correlation between Fe₂O₃ and V in hematite and goethite; the affinity of TiO₂ with HFSE (Hf, Nb, Th, Y and Zr) in heavy minerals. The ICV values suggest mature sediments. The PCI indicates a well-drained environment whereas U/Th and V/Cr ratios imply oxic conditions. La/Sc, La/Co, Th/Cr, Th/Sc and Eu/Eu* elemental ratios suggest a source with felsic components. Discrimination diagrams are consistent with the felsic source. The REE patterns of some High-K granite and granodiorite of the Congo Craton resemble those of the samples, indicating that they derive from similar source rocks.  相似文献   

云南澜沦南现铜铅锌多金属矿成矿地质条件     

王炳华  黄跃  邢程  毕晓路 《云南地质》2013,(4):433-435

铜铅锌矿赋存于中侏罗统花开左组浅色岩系和杂色岩系破碎带中,为受层位控制的砂页岩型铜矿及受构造控制的热液型铅锌多金属矿床.  相似文献   

陕西洛南灵口西沟含银铅锌矿床成矿模式     

成亚利  周富民  张毅  张三龙 《云南地质》2013,(4):436-438,456

围绕碾沟复式花岗岩和闪长岩,发育一组时间、空间、成因有联系的不同类型矿体——斑岩型、矽卡岩型和沉积改造型.从岩体中心→接触带→围岩,成矿元素显Mo→Cu （Mo） →Pb、En,Ag变化规律.受地层层位及构造控制.  相似文献   

随钻伽马测井快速正演算法及地质导向应用   总被引：4，自引：1，他引：3       下载免费PDF全文

邵才瑞  曹先军  陈国兴  张福明  姬嘉琦  唐建红 《地球物理学报》2013,56(11):3932-3942

在定向井及水平井钻井过程中,常采用地质导向技术;地质导向的关键在于实时确定地层界面和产状、实现地层模型的实时更新和井眼轨迹的及时调整,从而最大限度地提高油层的钻遇率.利用基于地层模型的测井响应正演曲线与随钻测井曲线进行对比是确定地层界面的有效方法;本文基于伽马射线在地层中的衰减规律,导出了不同地层模型中随钻伽马测井响应快速正演算法,克服了目前难以将蒙特卡罗算法用于实时随钻伽马测井正演的困难.应用实例表明该方法可以有效地辅助实时判定实际地层界面,更好地实现地质导向.  相似文献   

Water inrush and environmental impact of shallow seam mining   总被引：2，自引：1，他引：2  

Jincai Zhang  Suping Peng 《Environmental Geology》2005,48(8):1068-1076

Shallow seam mining is very common in China for enhancing coal recovery. However, this may cause a series of severe problems in environment and mining safety in some cases, because the alluvium aquifers are directly above the shallow coal seams. Some typical water and sand inrush incidents resulting from shallow mining in China are analyzed. Based on in-situ observation, the mining-induced strata failures are investigated. The height of the fractured zone decreases as the size of the outcrop pillar or mining depth decreases. The spatial distributions of the failure zones in the shallow mining have specific features compared to the deep mining. These provide an advantageous condition for the shallow mining under alluvial aquifers. Optimal designs for outcrop pillar sizes are also given in different hydrogeological conditions for environment friendly and production-safe mining at shallow depths. According to in-situ mining experiments in several coalfields, technical measures for shallow mining are presented. These primarily include the lift mining for thick seams and reduction of the thickness of extraction in the first lift, short-wall mining, and detection of faults and other potential hazards prior to mining.  相似文献   

鄂尔多斯盆地西南缘奥陶系的对比划分意见及其对中西部油气勘探的意义   总被引：2，自引：0，他引：2  

孙肇才  胡显穆 《海相油气地质》2002,7(4):41-58

根据野外实测剖面及多年积累的古生物地层资料,建立了鄂尔多斯盆地西南缘包括2个群及以笔石带为据的9个组。强调下奥陶统与中—上奥陶统是该区及整个中国中西部地区的一个重要层序和盆地原型分界。代表 SaukⅢ上部的下奥陶统在鄂尔多斯、塔里木和扬子地区表现为被动边缘上的以台地相碳酸盐岩占优势的伸展盆地沉积,其顶部风化壳是本区及塔里木大油(气)田的主力储层。以 Tippecanoe(O_2—D_(?))层序和以中—上奥陶统为主的地层,是鄂尔多斯和塔里木最有价值的有效烃源岩层,它代表了加里东期聚敛到碰撞的挠曲型复理石至磨拉石前陆盆地的沉积,而古中央隆起是这个弧后前陆的前隆部位。  相似文献   

新疆萨热阔布地区水系沉积物地球化学异常特征及找矿前景分析     

宁志熙 《矿产与地质》2001,15(6):718-723

萨热阔布地区水系沉积物地球化学异常及矿产的分布与泥盆系下统康布铁堡组上亚组第一、二岩性段有密切的成矿关系。异常规模较大，且成群成带分布，是金及铅锌银铜多金属找矿的有利靶区。  相似文献   

南京-仪征地区新近纪砂砾层层序及古长江的形成与演化     

张祥云  刘志平  范迪富  蒋梦林  邵家骥 《江苏地质》2003,27(3):140-147

对南京—仪征地区新近纪砂砾层层序、时代进行了讨论。该地区新近纪砂砾层地层层序为中新世中期的洞玄观组(Nld)、中新世晚期的六合组(N1l)、黄岗组(N1h)及上新世的雨花台组(N2y)，认为雨花台组沉积是位于六合组之上的另一套砂砾层，其沉积时代为上新世晚期。还分析了新近纪砂砾层在中新世中期、中新世晚期、上新世的沉积环境，探讨了区内古长江的形成与演化，认为古长江是在古近纪断陷盆地的基础上，经历了中新世多个汇水盆地的发育阶段至上新世形成古长江雏形，并于更新世早期基本定型，其形成及演化过程均与新构造活动息息相关。  相似文献