屯溪地区震旦纪岩相古地理研究     

彭花明 《华东地质学院学报》1996,19(4):382-386

安徽屯溪地区震旦系下统碎屑岩系和上统碳酸盐，硅质沉积岩组成，沉积相序由河流相，滨海相，陆棚相和深水盆地相组成，反映了裂陷盆地的特征。  相似文献   

冀西北麻粒岩相花岗质片麻岩中矿物的流体包裹体特征及其地质意义   总被引：2，自引：0，他引：2  

耿元生  沈其韩  李荫清 《岩石学报》1996,12(2)

本文报道了冀西北地区麻粒岩相片麻岩中矿物内流体包裹体的特征并讨论了其地质意义。根据包裹体的形态、赋存状态并结合包裹体ＣＯ２密度的演化，在麻粒岩相花岗质片麻岩的矿物中可识别出四种类型的流体包裹体：１）一相富ＣＯ２包裹体、２）气液两相富ＣＯ２包裹体、３）三相含液态ＣＯ２包裹体，４）含石盐子晶的多相包裹体。不同类型包裹体的特征和密度等表明，该区花岗质片麻岩经历了三个阶段的变质过程。第一阶段，在麻粒岩相变质作用峰期之后捕获了高密度的富ＣＯ２包裹体。在第二阶段形成了两相富ＣＯ２包裹体。第三阶段捕获了低密度的三相含液态ＣＯ２包裹体。这种很低密度的流体包裹体反映了晚期变形和退变质期间的温压条件  相似文献   

Palaeoenvironmental Changes of the Ancient Nihewan Lake Area—Sr Isotope Evidence from Xiaodukou Foraminifera     

王世杰 《中国地球化学学报》1996,15(2):105-112

By using the improved trace(50μg) Sr isotope analytical method the ^87Sr/^86Sr ratios of Xiaodukou foraminifera fossils were measured,giving a range of 0.71105-0.71274,apparently higher than the value of contemporaneous seawater(0.709087-0.709147)and also slightly higher than the average value of modern Yellow River(0.7111),demonstrating that the contemporaneous environment where Xiaodukou foraminifera inhabited was an inland lake.Detailed analyses of △ Sr values showed that there occurred an event responsible for environmental changes in the ancient Nihewan Lake area during the time(about 1.0Ma ago)when Xiaodukou foraminifera appeared.Because of strong evaporation the salinity of the lake would increase and a regional salt-water of brackish-water lacustrine environment would be produced,thus providing a suitable and inhabitable environment for foraminiferae.It is concluded that Xiaodukou foraminiferal fossil assemblaes belong to non-marine foraminiferal species.  相似文献   

Effective porosity and specific yield of a sedimentary rock determined by a field tracing test using tritium as a tracer     

H. Ii  Y. Ohtsuka  N. Mori  T. Inagaki  S. Misawa 《Environmental Geology》1996,27(3):170-177

Effective porosity value was analyzed from the tritium concentration of sampled groundwater using a three-dimensional groundwater-flow and advection-dispersion code based on the finite element method. The effective porosity value was about 10%. Porosity values measured from core samples were 7–15%. The groundwater flow velocity estimated from the tritium concentrations was about 1 × 10^–5 cm s^–1. Therefore, during the low groundwater flow velocity condition, effective porosity and porosity values were the same. At the same test site, a 0.48% effective porosity value, determined by another tracer test injecting Br^– solution into the aquifer during groundwater level change, was smaller than the porosity value when the flow velocity was 1.8×10^–2 cm s^–1. Thus the effective porosity value is concluded to be due to groundwater flow velocity. The specific yield value was calculated to be 0.6% by the total volume of tunnel seepage water and the total volume of the rock unsaturated during tunnel construction. However, as pore water continued to be drained after the groundwater level change was completed, the specific yield value became larger than 0.6%. Thus specific yield value is concluded to be due to drainage time.  相似文献   

对“指相矿物”海绿石的重新认识   总被引：3，自引：0，他引：3  

李东明  孙镇城  彭立才  王敏  王爱雷 《岩石矿物学杂志》1996,15(4):379-384

长期以来，海绿石一直被认为是在特定海洋条件下形成的自生矿物，被作为海相标志，随着陆相海绿石的不断发现，有必要对这一观点进行重新认识。本文通过对不同地区、不同环境中的海绿石的统计研究认为：海绿石既可以形成于海洋环境，也可以形成于陆相湖泊环境，海绿石不能作为海洋环境的指相矿物；一般来说，形成于陆相湖泊环境的海绿石与形成于海洋环境的海绿石相比，在化学成分上具有Ａｌ２Ｏ３、Ｋ２Ｏ含量高而ＦｅＯ含量低的特点  相似文献   

Stochastic simulation of categorical variables using a classification algorithm and simulated annealing   总被引：4，自引：0，他引：4  

P. Goovaerts 《Mathematical Geology》1996,28(7):909-921

An important step of reservoir characterization is the stochastic modeling of the geometry of lithofacies which control large-scale heterogeneities of petrophysical properties. Although multiple realizations are necessary to appreciate the uncertainty in the spatial distribution of facies, a common short cut consists of retaining the first realization drawn. This paper presents an alternative to this potentially hazardous selection: (1) a categorical map is generated by allocating a single facies to each grid node according to the local probabilities of occurrence of the facies, and (2) the map then is post-processed using a steepest descent-type algorithm so as to improve reproduction of spatial continuity and transition probabilities between facies. The procedure is illustrated using a synthetic dataset. A waterflood simulation shows that retaining a single realization would yield, in average, larger errors in production forecasts (water cuts and recovered oil) than the single postprocessed facies map.  相似文献   

淮北煤田下石盒子组七煤段沉积模式与聚煤特征   总被引：1，自引：0，他引：1  

胡宝林 《中国煤田地质》1996,8(2):23-25,74

煤田地质工作者发现，我国晚古生代煤系高建设性三角洲成煤作用尤为发育。采用地层垂直层序分析，砂体分析，岩矿及地化分析，测井曲线分析等方法，并编制了分析性图件，对本区七煤段进行剖析，认为该段是一套以浅水三角洲环境为主的沉积组成；同时，对其成煤特征进行了探讨。  相似文献   

淮北闸河矿区二叠系含煤地层沉积环境分析   总被引：3，自引：0，他引：3  

刘文中  徐龙 《中国煤田地质》1996,8(3):19-21

运用岩矿鉴定、光谱分析、Ｘ衍射、沉积磷酸盐分析等先进的实验手段，对淮北闸河矿区二叠系含煤地层的沉积特征进行了详细的研究。在沉积特征研究的基础上，确定本区二叠纪时为以河流作用为主的建设性河控浅水三角洲沉积环境。  相似文献   

周口坳陷早白垩世沉积相与沉积格局   总被引：1，自引：0，他引：1       下载免费PDF全文

李文厚  陈景维  邵磊 《沉积与特提斯地质》1996,16(1):44-50

周口坳陷早白垩世主要发育冲积扇相、河流相、湖泊相、扇三角洲相和三角洲相等类型，其中谭庄－沈丘凹陷沉积相带呈东西向狭长展布，是一个典型的断陷盆地．本文在讨论了湖盆的物源、古地形、古水流、水介质条件及古气候条件的基础上，提出了早白垩世时周口坳陷的沉积格局。  相似文献   

鲁西南石炭二叠纪煤系潮坪沉积体系与聚煤作用   总被引：2，自引：0，他引：2  

魏久传  李增学 《中国煤田地质》1995,7(3):25-30

鲁西南石炭二叠纪煤系形成于内陆表海盆地。潮坪沉积体系是研究区聚时重要的沉积体系之一。作者详细研究了潮坪沉积体系的内部构成、成因相及各种沉积体发育特点，分析了沉积组合类型及其成因单元，论述了潮坪沉积体系的聚煤特点及富单元的形成与分布规律。  相似文献