内蒙古中部中--晚志留世西别河组的划分和时代     

张永清孟二根  巩智镇韩建刚　王弢 《地质通报》2004,23(4):352-359

华北板块北缘早古生代造山带的稳定盖层西别河组是顶底清晰，下界不整合覆于早中奥陶世岛弧建造之上，其上被下泥盆统查干哈布组、上石炭统阿木山组不整合覆盖的一套稳定的滨浅海相沉积建造。本次工作根据岩石地层特征划分了砂砾岩段、灰岩段、砂板岩段和巴特敖包礁4个填图单元；在生物地层工作的基础上分别划分了2个珊瑚、腕足化石组合带，确立了该组为中晚志留世地层，即Wenlockian-Pridolian期的沉积。  相似文献   

Low-temperature constraints on the Alpine thermal evolution of the Western Carpathian basement rock complexes     

《Journal of Structural Geology》2016

The Cretaceous to Palaeogene Alpine exhumation of previously buried Variscan basements is recorded in the southern portion of the Western Carpathians in the Gemeric and Veporic units. The Meso-Cenozoic collisional processes resulted in basement exhumation of the Tatric Unit from Palaeogene to Neogene times. According to zircon and apatite fission track data, the Gemeric Unit, an uppermost thick-skinned thrust sheet, cooled from depth levels of ∼10 up to 2.5 km (temperature interval of ∼250–60 °C) about 88–64 Ma ago, after the collapse of overlying Meliata-Turňa-Silica Mesozoic accretionary prism. The middle and lower thick-skinned thrust sheets, Veporic and Tatric units, cooled from the depths of ∼10 up to 2.5 km ∼110–40 Ma ago. The process was controlled by unroofing of footwall from beneath the Gemeric Unit. About 50–20 Ma ago, the internal zone of Tatric Unit gradually exhumed to depth of <2 km and some parts of the unit appeared at the surface level. However, the external zone of Tatric Unit was buried beneath the Eocene to Lower Miocene sedimentary successions and exhumed to the subsurface level at ∼21–8 Ma ago, as a result of oblique collision of the Western Carpathians with the European Platform.  相似文献   

重力方法在祁连山地区构造特征与岩体解释中的应用   总被引：1，自引：1，他引：0       下载免费PDF全文

路利春  姜鸿  吴荣高  张佩  张冲  李陇锋 《中国地质调查》2018,5(3):95-103

依据地质、航磁等资料,结合实测岩石物性资料,以1∶250 000重力资料为基础对祁连山地区(张掖、刚察地区)进行综合研究。研究地质构造与地球物理特征,划分了大地构造单元,探讨了隐伏与半隐伏岩体分布。该区域经多年的重力工作,勘探面积已近3万多km²,根据重力资料研究布格重力场特征并进行分区; 对地质构造单元重新划分,对主要断裂进行探讨; 圈定隐伏与半隐伏岩体,推断其空间展布特征,并对其解释。结果表明: 祁连山地区地壳密度结构横向分区、纵向分层明显,布格重力异常场的分区特征与地质构造分区特征基本一致。结合2.5D重力剖面反演印证了新的推测结果,为综合地质、地球物理找矿提供参考。  相似文献   

松辽盆地北部三肇凹陷升554断块特低渗油气储层流动单元研究          下载免费PDF全文

周路路  刘俊刚  舒广强  刘志伟  陈璋  王双桃  汤刚  黎勤国 《中国地质》2021,48(3):807-819

油气储层流动单元在高、中、低渗储层表征中已经得到普遍应用,但在特低渗储层研究中仍然很少涉及。以松辽盆地北部三肇凹陷升554断块下白垩统泉头组四段扶余油层特低渗储层为例,划分出E、G、P三种流动单元类型,从E类至P类流动单元,渗流能力逐渐减小。流动单元物性特征、空间分布特征均表明流动单元储层非均质性较强。分析了沉积相及开启型正断层对流动单元发育的控制作用。研究发现,在特低渗储层尺度内,流动单元自身的渗流能力对油藏开发的作用已经很小,而不同流动单元之间的渗流能力差异引起油藏开发效果的不同也已不明显,开发效果主要取决于砂体射开厚度、注水效果等开发因素以及断层渗流通道、泥岩渗流屏障、砂体厚度等地质因素。这与以往储层流动单元研究中普遍认为的"流动单元渗流能力越强,油藏注水开发效果越好"的观点是截然不同的。通过本文以期为特低渗油气储层流动单元研究提供一定借鉴,为特低渗油藏开发提供一定参考依据。  相似文献   

麻粒岩区构造地质编图原则探讨   总被引：2，自引：0，他引：2  

李江海 《地质科技情报》1994,13(4):13-20

麻粒岩区的边界及亚区划分标志常为等变线、断层或剪切带。主要地质单元包括灰色片麻岩、花岗片麻岩、混合岩、副变质表壳岩、层状侵入体、高级变质绿岩等，基性岩墙群为划分不同地质单元、建立其相对时序的重要标志。以上单元普遍被构造叠置，常可识别出侵入关系。表壳岩系底部不整合及地层层序的研究对于认识大陆克拉通化过程及沉积环境演化具有重要意义。早期大规模水平构造先后被两类变形序列叠加，第１类与麻粒岩相变质发生于同  相似文献   

非均匀温度场中熔体结晶作用与科马提岩结构成因     

谭劲  赵珊茸 《地质科技情报》1994,13(4):35-40

具有重要岩石学和构造学意义的科马提岩，最吸引人同时又最令人困惑的特征之一是它的鬣刺结构和分层构造。本文从喷出地表的岩桨冷凝时温度分布、熔体性质与结晶作用的密切联系，把科马提岩浆喷发形成的岩流作为一个冷凝整体。通过与金属铸锭浇注成形和矿石冶炼生产的比较，发现它们在冷凝固结过程中温度场特征、熔体的性质、结晶能力和结晶方式都有十分相似的特点，并以此为出发点详细解析了科马提岩的鬣刺结构和岩石分层构造的形成  相似文献   

广西钦州地区侏罗纪地层新资料   总被引：1，自引：0，他引：1  

董宝林  陈耀 《地层学杂志》1995,19(1):25-29,57

钦州、钦州湾盆地的侏罗系划分与对比问题一直存在争议。本文根据钦州地区１／５万区调资料，提出一些新的认识；认为该区侏罗系下部可创建那周尾组，反映其与十万大山地区和桂东的西湾地区下侏罗统在岩性组合上的差异；明确了东兴组的含义及使用范围；首次报道了钦州盆地诛罗纪的孢粉组合并讨论了其地层学意义；根据钦州盆地沉积相序的特点，论述了钦州盆地的沉积背景及沉积环境的演化历史。  相似文献   

地震系统文献资源的现状及其发展对策     

梁凯利  赵小倩 《国际地震动态》1995,(2):14-17

本文概述了地震系统文献资源的现状及其发展对策，内容包括地震文献资源概况、地震文献资源的调查分析、地震系统文献资源建设中存在的主要问题以及地震文献资源建设发展对策。  相似文献   

Vertical sedimentation units in a barrier island washover fan     

S. P. Leatherman  A. T. Williams 《地球表面变化过程与地形》1983,8(2):141-150

Overwash is a major component of a barrier island's response to high energy conditions. Examination of the 19-20 March, 1975, storm deposits at Assateague Island, showed that an overwash sequence could be divided into sedimentation units. Interpretation depends upon defining textural and mineralogical combinations that can be logically ordered as a vertical sequence. If the sequence is depositional and formed from a single material, normal grading usually results; if polymineralogical and erosionally truncated, inverse grading with a top layer of heavy minerals can be formed via an in situ sorting process dependent on disturbance depth and overwash influence.  相似文献   

Vertical migration of municipal wastewater in deep injection well systems,South Florida,USA   总被引：1，自引：2，他引：1  

Robert G. Maliva  Weixing Guo  Thomas Missimer 《Hydrogeology Journal》2007,15(7):1387-1396

Deep well injection is widely used in South Florida, USA for wastewater disposal largely because of the presence of an injection zone (“boulder zone” of Floridan Aquifer System) that is capable of accepting very large quantities of fluids, in some wells over 75,000 m³/day. The greatest potential risk to public health associated with deep injection wells in South Florida is vertical migration of wastewater, containing pathogenic microorganisms and pollutants, into brackish-water aquifer zones that are being used for alternative water-supply projects such as aquifer storage and recovery. Upwards migration of municipal wastewater has occurred in a minority of South Florida injection systems. The results of solute-transport modeling using the SEAWAT program indicate that the measured vertical hydraulic conductivities of the rock matrix would allow for only minimal vertical migration. Fracturing at some sites increased the equivalent average vertical hydraulic conductivity of confining zone strata by approximately four orders of magnitude and allowed for vertical migration rates of up 80 m/year. Even where vertical migration was rapid, the documented transit times are likely long enough for the inactivation of pathogenic microorganisms.  相似文献