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<正> 塔里木盆地生物礁目前主要发现于轮南、塔中、巴楚等地区(图1),层位集中于中奥陶统的一间房组、上奥陶统的吐木休克组和良里塔格组,并以一间房地区的生物礁发育最完整。初步研究结果认为,生物礁主要呈长条状分布于两种沉积环境:(1)碳酸盐台地向台地斜坡过渡的台地边缘环境;(2)碳酸盐台地内的地形由平坦向较陡处转折的地带。造礁生物的含量可达30%以上,上奥陶统中主要有海绵、苔藓虫、层孔虫、珊瑚、托盘类、蓝绿藻、管孔藻等。中国以往仅有在陕西渭河以北地区、浙赣交界地区和湖北地区发现奥陶系生物礁的报道,本次发现结束了塔里木盆 相似文献
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前人的观点认为,早奥陶世的塔里木盆地是一个统一的“大碳酸盐岩台地”,斜坡相呈马蹄形发育在古城—轮南一线。通过对塔中地区满加1井—塔中29井一线及相邻地区下—中奥陶统的岩石学、沉积学和地震地层学等方面的研究,发现这一线的下奥陶统主要由一套较深水的斜坡及海槽沉积构成,其地层厚度和地震反射特征也明显与周边地区不同,认为塔中及相邻地区在早奥陶世期间已经从早期的塔里木“大碳酸盐台地”中分化独立出来,分裂成塔中—巴楚台地、古城台地、塘南台地三块孤立台地,以塔北隔海相望。各孤立台地周缘发育台地边缘高能礁滩沉积体,呈条带状展布,主要由中高能粒屑滩组成;向内相变为台地相,发育台内滩、台内洼地、滩间海等亚相;向外进入较深水的斜坡—海槽沉积区,从而确立了塔中及相邻地区早奥陶世新的区域沉积格局。新沉积格局的确立,对于确立下奥陶统新的有利勘探区带具有重要的理论和现实意义,大大提升了研究区下奥陶统的油气勘探战略地位。 相似文献
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礁滩体储层是中国目前碳酸盐岩勘探的重点。塔里木盆地奥陶系礁滩复合储集体发育,中奥陶统生物礁发育层位主要在一间房组,发育区集中分布在塔北、巴楚等地,并以开阔台地台内点礁方式出现。HD23井区内共有奥陶系探井4口,其中HD17井、HD13井、YW2井在中奥陶统一间房组都钻遇了托盘类瓶筐石（Calathium）障积礁,礁的厚度约5 m,礁的上下地层均为砂屑鲕粒灰岩和砂砾屑灰岩等滩相沉积,形成礁滩复合体。文中通过钻井资料和地球物理资料,深入研究了HD23井区礁滩体的特征与分布。三维地震解释显示一间房组地层中存在一个厚度异常体,经分析认为该异常体就是局部异常发育的瓶筐石生物礁滩复合体,该生物礁滩体横向连片,有一定的分布范围和规模。对该井区内中奥陶统一间房组的生物礁滩体加以研究,将为下一步奥陶系的油气勘探提供依据。 相似文献
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塔中地区礁滩储集体形成条件及分布规律 总被引：11，自引：0，他引：11
奥陶纪时期，塔中地区发育生物礁、丘和滩等不同类型的碳酸盐岩建隆生物礁丘发育层位主要集中在上奥陶统．塔中地区的礁滩相包括灰泥丘、中物礁、粒屑滩和地质异常体等4种类型，沉积古地理、构造作用、陆源碎屑物注入和海平面变化是控制生物礁发育的主要因素．塔中地区生物礁的分布环境主要有2个相带：一是台地内，尤其是半局限台地与开阔台地的转折处或台内缓坡上，如塘参1井、塔中23井上奥陶统的生物礁：另一个是台地边缘，如塔中45井-塔中44井-塔中24井-带为台缘外带，以发育中高能粒屑滩和骨架礁组合为特色，而大致在塔中35井-塔中12井-塔中15井-塔中161井-带为台缘内带，发育中低能粒屑滩、灰泥丘及障积礁组合． 相似文献
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<正> 早奥陶世,塔中地区为统一的开阔的碳酸盐台地,沉积一套巨厚的以石灰岩、白云质灰岩和灰质白云岩夹白云岩地层。下奥陶统沉积后,发生构造变形和抬升暴露,塔中低凸起形成,在其主体部位,下奥陶统顶部遭部分剥蚀。中奥陶世,以塔中低凸起为中心,中央高,南北两侧低,形成了碳酸盐台地—开阔陆棚的沉积体系。晚奥陶世,随着地壳整体下沉,海平面上升,碳酸盐台地逐渐收缩,陆源泥质沉积不断进积,但陆棚水体变浅,形成了碳酸盐台地—混积陆棚—开阔陆棚为特征的沉积体系。概括起来,塔中地区这两种前后发育的沉积体系包括了两个大的沉积相类型,即碳酸盐台地相 相似文献
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塔中Ⅰ号构造带是塔中地区重要的油气勘探区,已发现的油气田基本沿着塔中Ⅰ号构造带分布,塔中Ⅰ号构造带发育过程与塔中低凸起的形成演化密切相关。为了揭示塔中Ⅰ号构造带的活动期次、形成机制及塔中低凸起的形成演化过程,利用新的地震、测井、钻井资料,结合断层相关褶皱理论和平衡剖面复原技术,分析了塔中Ⅰ号构造带的几何学与运动学特征。研究结果表明：1） 塔中Ⅰ号构造带为受控于塔中低凸起基底断层转折褶皱向前传递的过程中形成的背斜构造带;2） 塔中地区识别出了上奥陶统、志留系两套生长地层,表明塔中Ⅰ号构造带主要活动时间为中晚奥陶世-志留纪;3） 塔中低凸起东部构造活动强于中西部,东部累计缩短量为58.14 km,累计缩短率为20.84%。综上,认为塔中低凸起的形成与演化是受控于早奥陶世末至晚奥陶世挤压构造背景下,基底发育断层转折褶皱,晚奥陶世以后,塔中低凸起进入构造拓宽期。早海西期,基底断裂活动基本停止,塔中低凸起基本定型。 相似文献
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1 加里东中期岩溶存在的证据 1.1 地震解释提供的依据 区域二维地震剖面 区域二维地震剖面解释表明,从满加尔坳陷至阿克库勒凸起,中上奥陶统逐层超覆于下奥陶统之上,说明其间存在间断和缺失.塔河油区三维连片及兰尕三维地震解释成果表明,本区南部中上奥陶统与下奥陶统为超覆关系,说明其间存在间断和缺失. 1.2 地层古生物依据 塔中低凸和巴楚断隆下奥陶统与中奥陶统间存在明显间断,缺失早奥陶世晚期—中奥陶世早期沉积,缺失至少8个牙形刺带,沉积间断延续30~50 Ma.在塔河油田南部的S69、LN16等井中发现下奥陶统与中上奥陶统间至少缺失P… 相似文献
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塔里木盆地下奥陶统蓬莱坝组沉积相特征 总被引：1，自引：0，他引：1
以钻井岩心、测井数据及地震资料为基础,运用岩相古地理学、地震地层学、层序地层学等学科方法原理,对塔里木盆地下奥陶统蓬莱坝组沉积相特征进行研究,认为下奥陶统蓬莱坝组发育局限台地相、开阔台地相、台地边缘相、斜坡相和盆地相.局限台地主要分布在塔中、塔东及塔西南大部分地区,开阔台地只在塔北局部地区发育.对钻井岩心、薄片资料、连井剖面、地震相进行综合分析研究后,绘制出蓬莱坝组沉积相平面展布图,据该组沉积相平面展布规律,综合考虑该时期沉积演化及古地理背景,建立起塔里木盆地下奥陶统蓬莱坝组沉积相模式. 相似文献
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CSAMT 法在辽西康杖子区深部探矿中的应用 总被引：5，自引：0，他引：5
可控源音频大地电磁法(CSAMT)具有探测深度大、横向分辨率高、抗干扰能力强的特点,在深部找矿勘探中有着重要的指导意义。肖家营子铜钼矿床是辽西地区一个大型矽卡岩型金属矿床,大部分矿体是隐伏矿体,矿区外围的康杖子区与本区有相似的成矿地质环境,成矿地质条件优越.矿体与围岩电性差异明显,通过应用CSAMT,矿体具有低电阻特点,根据成果推断解释,对深部有利成矿部位进行了钻探验证,取得了理想的探矿效果,在矿区外围取得第二深度空间找矿重大突破。 相似文献
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Julie Okpala 《GeoJournal》1990,20(1):37-43
This paper traces the development of geographic education in Nigeria and examines the views of geographers, other academics,
students and the public at large about the importance of geography. Geography's value is immense despite the non-professional
nature of the discipline. Nevertheless, there is a need to define geography's status and ensure career prospects for students.
The Nigerian Geographical Association (from classroom teaachers to top geographers) must promote geography, improve its status
in schools and universities, and continuously restructure its content and methods to address pertinent social needs. 相似文献
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Trends in landslide occurrence in Nepal 总被引：2，自引：0，他引：2
David N. Petley Gareth J. Hearn Andrew Hart Nicholas J. Rosser Stuart A. Dunning Katie Oven Wishart A. Mitchell 《Natural Hazards》2007,43(1):23-44
Nepal is a mountainous, less developed kingdom that straddles the boundary between the Indian and Himalayan tectonic plates.
In Nepal, landslides represent a major constraint on development, causing high levels of economic loss and substantial numbers
of fatalities each year. There is a general consensus that the impacts of landslides in countries such as Nepal are increasing
with time, but until now there has been little or no quantitative data to support this view, or to explain the causes of the
increases. In this paper, a database of landslide fatalities in Nepal has been compiled and analysed for the period 1978–2005.
The database suggests that there is a high level of variability in the occurrence of landslides from year to year, but that
the overall trend is upward. Analyses of the trends in the data suggest that there is a cyclicity in the occurrence of landslide
fatalities that strongly mirrors the cyclicity observed in the SW (summer) monsoon in South Asia. Perhaps surprisingly the
relationship is inverse, but this is explained through an inverse relationship between monsoon strength and the amount of
precipitation in the Hill District areas of Nepal. It is also clear that in recent years the number of fatalities has increased
dramatically over and above the effects of the monsoon cycle. Three explanations are explored for this: land-use change, the
effects of the ongoing civil war in Nepal, and road building. It is concluded that a major component of the generally upward
trend in landslide impact probably results from the rural road-building programme, and its attendant changes to physical and
natural systems. 相似文献
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2010年,美国铀矿总共施工7 209个钻孔,总进尺1 493 520 m;生产铀1 628.55 t;铀矿业总支出费用为2.773亿美元,其中铀矿地勘费支出为3 450万美元,占铀矿业总费用的12.44%。铀矿地勘钻探费用为4 460万美元,占铀矿业总费用的16.08%。 相似文献
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硫代砷是富硫化物地下水中砷的重要形态,对环境和人类健康有潜在威胁。目前硫代砷研究程度尚低,本次主要针对国内外地下水（地热水）中硫代砷的存在形态,水文—生物—环境地球化学过程,样品保存,定量检测方法等方面进行研究。结论如下:pH, 氧化还原电位,硫化物含量和微生物作用等是影响地下水中硫代砷稳定存在和形态分布的重要因素。含铁矿物能与水中的硫代砷形成配位键对其进行吸附,吸附性普遍弱于（亚）砷酸盐,因此,地下水中硫代砷可能表现出更强的迁移性。用于硫代砷检测的自然水样在采集中可采取过滤,速冻,厌氧和低温短期保存的操作流程,以减缓该形态的转化甚至消失。色谱联用ICP-MS系统可用于自然水样中硫代砷的分离定量检测,紫外—可见分光光度法和X射线吸收光谱法在不同场景下也可对硫代砷进行定量和表征分析。地热水和浅层地下水中均可能存在硫代砷,由于水样中硫代砷的不稳定性,室内检测和分析难以准确反映现场过程,因此,野外样品保存技术和现场检测方法的更新可能在未来有更大研究空间,值得进一步探索。 相似文献
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Takeshi Nose Dr. 《GeoJournal》1985,10(3):261-276
Conclusions During the last ten years, aquaculture, especially mariculture has undergone remarkable expansion to counter-balance the gap between the supply and demand of fishery products in Japan. Its expansion has also been supported by the traditional preference of the Japanese people for seafood. Mariculture is now being forced to change its structure due to adverse economic circumstances such as the rise in the cost of energy, feeds and other materials for culture, low market prices, deterioration of environmental conditions, and many other factors. Before these constraints can be resolved, advanced scientific knowledge and technologies must be integrated to develop new types of aquaculture. Expansion of maricultural activities to more open-sea and off shore areas would be one route to follow. Technologies for the development of formulated diets not only for young but also for adults and larvae, establishment of feeding standards, prevention of epizootic diseases must support the establishment of modern aquaculture.The culture-based fisheries, or marine ranching, is becoming a subject for further development in Japan. Much research work has been conducted with a great degree of governmental support. Establishment of a net work of seedstock production farms has made it possible to carry out releasing experiments on a large scale. A newly integrated restoration system could be developed on the basis of these experiments, even though the profits resulting from the artificial restoration of stocks is not thouroughly verified at present. The commencement of a national scheme for culture-based fisheries would be a manifestation of the enthusiasm of the Japanese fish industry. 相似文献
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Radon is a radioactive gas emanating naturally from uranium rich granites and shales. It may be emitted from the ground surface into the atmosphere as a gas, or it may be dissolved into stream water and transported over distance. The levels of radon gas in soils at ground surface depend on a number of factors relating to the source of the gas and to its transmission. Igneous rocks contain the highest mean concentrations of radium and uranium. The depth of cover is relevant also. Surveys over the years by the National Radiological Protection Board (NRPB) and others have indicated that the highest concentrations in the United Kingdom occur in Cornwall, Devon and northeast Scotland. However, recent reports have indicated that high concentrations of the gas may be detected in small pockets in counties outside of those considered at high risk. This survey relates to a series of measurements taken in and around Darlington, County Durham. The results showed the presence of small areas with strong concentrations of radon in soil gas, but only minor levels of dissolved gas in stream waters. 相似文献
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内蒙古苏尼特地下水氟污染形成机理研究 总被引：4，自引：1，他引：3
为了研究内蒙古苏尼特地区地下水氟污染机理,本文运用水文地球化学分类方法,从水文地质、水化学特征两方面研究其地下水的水质特征、氟的起源、分布规律及污染形成机理。研究结果发现:高氟地下水的主要水质类型为HCO3—Na型,pH值在7.08～9.38之间,氟浓度与井深有关,即井越浅,氟浓度越高;地下水中氟浓度最高达14.78mg/L,5～9月地下水氟浓度相对增长率在7.8～23.1之间;F-浓度与Li+、Br-相关系数达0.89和0.82,受断层影响的深层地下水中F-浓度几乎与Li+、Br-没有相关关系,这暗示着氟来源于浅部,并受到强烈的蒸发作用影响而使水中的氟浓缩;地质调查发现该地区还有数个萤石矿存在,显微镜分析结果证实表层土壤中普遍存在CaF2,地下水中的氟来自CaF2。高氟地下水存在于潜水层,深部含水层的地下水可供开采。从断层带涌出的水对潜水层有稀释作用。 相似文献