Textural and Geochemical Characteristics of Proglacial Sediments: A Case Study in the Foreland of the Nelson Ice Cap, Antarctica   总被引：1，自引：0，他引：1  

LIU Xiaodong  SUN Liguang  YIN XuebinInstitute of Polar Environment  University of Science  Technology of Chin  Hefei  Anhui 《《地质学报》英文版》2004,78(4):970-981

This paper presents a detailed study on the textural and geochemical characteristics of the proglacial sediments near the edge of modern Nelson Ice Cap, Antarctica. The grain size distributions of the proglacial sediments are characteristic of glacigenic deposits, but very different from those of aeolian and lacustrine sediments. Moreover, the grain size distributions of the proglacial sediments are fractal with a dimension of about 2.9, and the fractal dimensions can be used as another summary statistical parameter for quantifying the relative amounts of coarse and fine materials. Correlations between the absolute element abundances of the proglacial sediments are very weak due to mineral partitioning and other effects of glacial processes, but correlations between the element/Rb ratios are statistically significant. This finding indicates that element/Rb ratios can be used to reduce or eliminate the effects of glacial processes, evaluate geochemical data and determine the sediment provenance in the for  相似文献   

山东小清河流域湖泊的环境变迁   总被引：6，自引：3，他引：3       下载免费PDF全文

张祖陆  聂晓红  卞学昌 《古地理学报》2004,6(2):226-233

小清河流域为西起济南,东至渤海湾,南缘泰鲁沂山地北麓,北界黄河之间的区域。在史前及历史时期,小清河流域湖泊广布,在地层沉积记录和古文献记载中均得以证明。这些湖泊形成于早全新世,在中全新世达到鼎盛,晚全新世以来湖泊逐渐衰退与消亡,如原来存在的鹊山湖、浒山湖、清水泊等湖泊,这在古文献中也多有记载,现已在平原上消失。本文着重对麻大湖、锦秋湖、白云湖等的历史演变进行了探讨。通过查阅历史文献、地层剖面分析、地名考证等多种途径和方法对小清河流域的湖泊消失的原因进行了研究和分析。认为在气候变干的大背景下,湖泊消失的原因主要有两个：一是黄河泛滥所造成的小清河流域的泥沙淤积;二是疏浚河道、围湖造田、过渡利用水资源等人类活动的影响。研究本区湖泊的形成与消亡,对恢复古环境、探讨其演变过程有着重要的意义。  相似文献   

Predicting Terrestrial Flagstone Reservoirs in the Sha-I Member of the Qibei Depression in the Dagang Oilfield     

LEI Huaiyan  LIU Zhihong  XU Maoquan  GUAN Baocong Institute of Oceanography  Environment  Xiamen University  Xiamen  Fujian State Key Laboratory of Gas Geochemistry  Institute of Geology  Chinese Academy of Sciences  Lanzhou  Gansu 《《地质学报》英文版》2004,78(3):701-714

There are few 3-D seismic profiles and drillings in the middle part of the Qibei depression in the Dagang oilfield, and more than 70% of the 2-D seismic profiles were completed before the 1980s. Meanwhile, changes in the terrestrial formations in this region have been large and complex. These factors have made it difficult to predict reservoirs in this area. The purpose of this paper is to establish a methodology for predicting potential gas and oil reservoirs. Our research combines sequence stratigraphy, well-logs, and seismic analysis to elucidate the prediction of flagstone reservoirs in the S1 (Sha-I) Member in the middle of the Qibei depression. Previous research indicates that these rocks were deposited in an environment that had a semiarid, northern subtropical, and warm, humid climate. The objective strata currently consist mainly of lake fades, deeper lake facies, and shore-shallow lake facies. The study reveals that the lower section of the S1 Member is an important objective region for explora  相似文献   

Calculation of the Model of Coesite Inclusions and Analysis of Their Retrometamorphic Paths     

MENG Dawei  DING Xiaokun  WU XiulingFaculty of Materials Science  Chemical Engineering  China University ofGeosciences  Wuhan  Hubei Testing Centre  China University of Geosciences  Wuhan  Hubei 《《地质学报》英文版》2004,78(1):166-169

The process and path of retrometamorphism of coesite have great significance to our understanding of the P-T tracks of the exhumation of ultrahigh-pressure metamorphic rocks. Most of the coesites in the eclogite from Shima, Anhui Province, the Dabie Mountains, China, are found degraded to quartz partly or wholly, with ruptures occurring in the shells, outside which include the coesite and quartz. According to the microscopic observation, the sample of coesite inclusion is composed of garnet, quartz and coesite, based on which we have built a three-shelled composite sphere model to compute the transition of coesite. Based on the crystal growth formulas and pressure conditions of the ruptures in the garnet, we have calculated the radius of the quartz sphere, which depends on temperature, and eventually drawn the different retrometamorphic paths for different retrometamorphism rates.  相似文献   

A Simple Monte Carlo Method for Locating the Three-dimensional Critical Slip Surface of a Slope   总被引：2，自引：0，他引：2  

XIE Mowen Institute of Environmental Systems  Kyushu University  Hakozaki --  Higashi Ku  Fukuok  Japan College of Resource Engineering  the University of Science  Technology Beijing  Xueyuan Ro  Haidian District  Beijing  China 《《地质学报》英文版》2004,78(6):1258-1266

Based on the assumption of the plain-strain problem, various optimization or random search methods have been developed for locating the critical slip surfaces in slope-stability analysis, but none of such methods is applicable to the 3D case. In this paper, a simple Monte Carlo random simulation method is proposed to identify the 3D critical slip surface. Assuming the initial slip to be the lower part of a slip ellipsoid, the 3D critical slip surface is located by means of a minimized 3D safety factor. A column-based 3D slope stability analysis model is used to calculate this factor. In this study, some practical cases of known minimum safety factors and critical slip surfaces in 2D analysis are extended to 3D slope problems to locate the critical slip surfaces. Compared with the 2D result, the resulting 3D critical slip surface has no apparent difference in terms of only cross section, but the associated 3D safety factor is definitely higher.  相似文献   

信息科学与矿产预测     

杨中宝  彭省临  银霞  李朝艳 《化工矿产地质》2004,26(1):41-44

矿产预测实质上就是对成矿系统演化过程精确性表达的探索,现代信息科学的发展为理解成矿系统的非线性特性以及信息运动过程提供了必要的理论基础。通过信息与成矿信息、虚拟现实技术与成矿预测可视化和信息模型与成矿系统三个方面探讨信息科学的发展与矿产预测之间的紧密联系,预测未来成矿预测将向定量化、精细化的方向发展,对矿的定位预测从以分析为主向分析与综合相结合方向发展。  相似文献   

Numerical Simulation of Abnormal Wave Height Change Induced by Excavated Waterway with Boussinesq Equation     

Zhang Yonggang  Li Yucheng Associate Professor  Dept. of Mechanic Engineering  Shanghai Jiao Tong University  Shanghai Professor  Dept. of Civil Engineering  Dalian University of Technology  Dalian 《中国海洋工程》1998,(1)

A nonlinear numerical model has been set up by use of Boussinesq Equation with finite differ-ence method,and has been applied to the simulation of the abnormal change of wave height induced by ex-cavated waterway.Numerical results demonstrate that the abnormal change of wave height is due to theadding of the reflected wave height induced by excavated waterway to the incident wave height.Becausethe angle between the incident wave and the axis of the waterway is smaller than the critical angle,the re-flected wave produced by the waterway may propagate to the breakwater and may be added with the inci-dent wave,then the abnormal change of wave height before the breakwater may be caused.So the wave re-flection caused by the change of water depth cannot be neglected.  相似文献   

浅谈对“混合土”的认识及其地基处理     

姜中笑 《湖南地质》1999,(Z1)

“混合土”是一种特殊性土,成分复杂,粒径悬殊,力学性质变化较大。本文以株洲市南华花园地区“混合土”为例,剖析了勘察中应注意的事项,阐述了动力触探是对“混合土”勘察的有效手段,并结合工程实际情况,提出了相应的地基处理措施。  相似文献   

累托石制备润滑脂的初步研究   总被引：6，自引：0，他引：6  

黄焱球  高广立 《矿物岩石》1999,19(1):88-91

累托石是一种具有独特的结构组成和性质的粘土矿物,其既具有象蒙脱石一样的阳离子交换性,吸水膨胀性,制浆性等,又具有象云母一样的耐高温性和光滑性等性能。经提纯和有机改性后的累托石吸油速度快,膨胀率高,是一种较好的稠化剂,用它制备的润滑脂滴点〉６３３．１５Ｋ,远高于膨润土润滑脂的指标要求,研究表明,累托石是制备润肖脂稠化剂的好原料,累托石润滑脂是一种新型高温润滑脂。  相似文献   

西北干旱区土壤资源特征与可持续发展     

WANG Genxu  CHENG Guodong 《地球科学进展》1999

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