论四川盆地三叠系地下水水文地质条件   总被引：3，自引：0，他引：3       下载免费PDF全文

林耀庭 《盐湖研究》2006,14(1):1-8

四川盆地三叠系地下水可划分出碎屑岩孔隙裂隙和碳酸盐岩岩溶裂隙两大储集类型。按此处构造开启程度和埋深条件等的不同,下中三叠统地下水有沉积变质水和渗入淋滤水两种基本成因类型,水动力特征各异。沉积变质水处于深埋封闭条件,受地静压力驱动控制;渗入淋滤水分布于背斜露头区和浅部地区,受静水压力驱动控制。并由此控制了盆地三叠系盐类的保存条件。  相似文献   

The petroleum generation potential and effective oil window of humic coals related to coal composition and age   总被引：1，自引：0，他引：1  

Henrik I. Petersen   《International Journal of Coal Geology》2006,67(4):221-248

A worldwide data set of more than 500 humic coals from the major coal-forming geological periods has been used to analyse the evolution in the remaining (Hydrogen Index, HI) and total (Quality Index, QI) generation potentials with increasing thermal maturity and the ‘effective oil window’ (‘oil expulsion window’). All samples describe HI and QI bands that are broad at low maturities and that gradually narrow with increasing maturity. The oil generation potential is completely exhausted at a vitrinite reflectance of 2.0–2.2%R_o or T_max of 500–510 °C. The initial large variation in the generation potential is related to the original depositional conditions, particularly the degree of marine influence and the formation of hydrogen-enriched vitrinite, as suggested by increased sulphur and hydrogen contents. During initial thermal maturation the HI increases to a maximum value, HI_max. Similarly, QI increases to a maximum value, QI_max. This increase in HI and QI is related to the formation of an additional generation potential in the coal structure. The decline in QI with further maturation is indicating onset of initial oil expulsion, which precedes efficient expulsion. Liquid petroleum generation from humic coals is thus a complex, three-phase process: (i) onset of petroleum generation, (ii) petroleum build-up in the coal, and (iii) initial oil expulsion followed by efficient oil expulsion (corresponding to the effective oil window). Efficient oil expulsion is indicated by a decline in the Bitumen Index (BI) when plotted against vitrinite reflectance or T_max. This means that in humic coals the vitrinite reflectance or T_max values at which onset of petroleum generation occurs cannot be used to establish the start of the effective oil window. The start of the effective oil window occurs within the vitrinite reflectance range 0.85–1.05%R_o or T_max range 440–455 °C and the oil window extends to 1.5–2.0%R_o or 470–510 °C. For general use, an effective oil window is proposed to occur from 0.85 to 1.7%R_o or from 440 to 490 °C. Specific ranges for HI_max and the effective oil window can be defined for Cenozoic, Jurassic, Permian, and Carboniferous coals. Cenozoic coals reach the highest HI_max values (220–370 mg HC/g TOC), and for the most oil-prone Cenozoic coals the effective oil window may possibly range from 0.65 to 2.0%R_o or 430 to 510 °C. In contrast, the most oil-prone Jurassic, Permian and Carboniferous coals reach the expulsion threshold at a vitrinite reflectance of 0.85–0.9%R_o or T_max of 440–445 °C.  相似文献   

Fe and Mn in calcites cementing red beds: A record of oxidation–reduction conditions: Examples from the Catalan Coastal Ranges (NE Spain)     

D. Parcerisa  D. Gmez-Gras  A. Trav  J.D. Martín-Martín  E. Maestro 《Journal of Geochemical Exploration》2006,89(1-3):318

Fe and Mn occur in calcite cements depending on the oxidizing–reducing conditions of cementing waters, which may change according to depositional and diagenetic environments. In red beds, Mn and Fe are available from the ferruginous matrix. Thus, it is possible to know the oxidizing–reducing conditions of fluids that precipitated calcite as a function of Mn and Fe content in calcite cement. A detailed petrological (with special attention to cathodoluminescence) and geochemical analysis of these cements is a useful tool to constrain the diagenetic evolution of red beds and the history of the basin where they deposited.  相似文献   

Hydrogeology of thermal waters in Viterbo area, central Italy     

V. Piscopo  M. Barbieri  V. Monetti  G. Pagano  S. Pistoni  E. Ruggi  D. Stanzione 《Hydrogeology Journal》2006,14(8):1508-1521

A conceptual hydrogeological model of the Viterbo thermal area (central Italy) has been developed. Though numerous studies have been conducted on its geological, geochemical and geothermal features, there is no generalized picture defining the origin and yield of the hydrothermal system. These latter aspects have therefore become the objectives of this research, which is based on new hydrogeological and geochemical investigations. The geological setting results in the coexistence of overlapped interacting aquifers. The shallow volcanic aquifer, characterized by fresh waters, is fed from the area around the Cimini Mountains and is limited at its base by the semiconfining marly-calcareous-arenaceous complex and low-permeability clays. To the west of Viterbo, vertical upflows of thermal waters of the sulphate-chloride-alkaline-earth type with higher gas contents, are due to the locally uplifted carbonate reservoir, the reduced thickness of the semiconfining layer and the high local geothermal gradient. The hot waters (30–60°C) are the result of deep circulation within the carbonate rocks (0.5–1.8 km) and have the same recharge area as the volcanic aquifer. The upward flow in the Viterbo thermal area is at least 0.1 m³/s. This flow feeds springs and deep wells, also recharging the volcanic aquifer from below.  相似文献   

Temperature dependence of large-scale water-retention curves: a case study     

Hui-Hai Liu  G. S. Bodvarsson  J. H. Dane 《Hydrogeology Journal》2006,14(8):1403-1408

A local-scale model for temperature-dependence of water-retention curves may be applicable to large scales. Consideration of this temperature dependence is important for modeling unsaturated flow and transport in the subsurface in numerous cases. Although significant progress has been made in understanding and modeling this temperature effect, almost all the previous studies have been limited to small scales (on the order of several centimeters). Numerical experiments were used to investigate the possibility of extending a local-scale model for the temperature-dependence of water retention curves to large scales (on the order of meters). Temperature effects on large-scale hydraulic properties are of interest in many practical applications. Numerical experiment results indicate that the local-scale model can indeed be applicable to large-scale problems for special porous media with high air entry values. A typical porous medium of this kind is the porous tuff matrix in the unsaturated zone of Yucca Mountain, Nevada, the proposed geologic disposal site for national high-level nuclear wastes. Whether this finding can approximately hold for general cases needs to be investigated in future studies.  相似文献   

Control of dust emissions by geomorphic conditions, wind environments and land use in northern China: An examination based on dust storm frequency from 1960 to 2003   总被引：9，自引：1，他引：9  

Xunming Wang  Zijiang Zhou  Zhibao Dong 《Geomorphology》2006,81(3-4):292-308

The degree to which dust emissions are controlled by geomorphic conditions, wind environments and land use was investigated using the dust storm frequency (DSF) and data from more than 300 meteorological stations throughout northern China. Our analysis showed that most dust emissions originated in gobi deserts that developed in piedmont alluvial fans of the Kunlun, Qilian and Helan mountains. Dust emissions are low from other gobi desert regions, such as the northern Gurbantunggut and eastern Taklimakan, where high vegetation coverage restrained dust emissions or where dust-size particles are not abundant after a long period of strong wind erosion. Sandy deserts with relatively high vegetation coverage or an extensive cover by mobile sands are not a major dust source. Although the highest dust emissions did not appear in regions with the highest wind energy, DSF trends in each region from 1960 to 2003 were closely related to local wind activity. DSF was low in regions with high levels of human activity, where the mean DSF from 1960 to 2003 did not exceed 4 days/year; even from the 1960s to the early 1970s, the period with the greatest DSF, frequency did not exceed 8 days/year, which indicates that extensive land use did not contribute to DSF. The low DSF in these areas might result from the fact that although land use could produce abundant fine soil fractions, vegetation coverage and soil moisture remained higher than in the gobi deserts of arid China, thereby decreasing dust-storm occurrence.  相似文献   

秦皇岛市矿产开发引发的地质环境问题及对策   总被引：2，自引：0，他引：2  

任志军 《化工矿产地质》2006,28(2):94-100

秦皇岛市矿产资源丰富,矿业已成为秦皇岛市特别是地方经济的支柱之一。伴随着矿业的发展,在矿产开发过程中引发的地质环境问题日益突出,如采空区地表变形(地面塌陷、地裂缝等)、岩溶塌陷、露天采矿边坡失稳、尾矿引发的泥石流、水土流失以及地貌景观的破坏等。这些地质环境问题主要分布在北部的山区和丘陵台地区。形成的原因复杂,主要有法制不健全、缺乏强制恢复机制、布局不合理、监管不到位、开采技术落后、不合理开采、资金缺乏以及从业者环保意识淡薄等方面的原因。对于矿山地质环境的保护,应采取加强立法、建立保证金制度、统一规划、加强监管、加大宣传力度以及建立责任追究制度等措施。  相似文献   

四川省康定县滑坡灾害发育特征与形成条件   总被引：3，自引：0，他引：3  

刘岁海  刘爱平 《中国地质灾害与防治学报》2006,17(3):27-31

康定县地处四川盆地西缘山地及青藏高原过渡地带。县域内地势险峻,地形切割强烈,地层与地质构造复杂,新构造运动强烈,地震活动频繁。加之降水充沛,致使山地灾害十分发育,其中滑坡灾害占山地灾害的38.32%。通过搜集资料及现场调查,概述了该县县域内滑坡灾害的分布;从行政区划、自然地理及灾害规模等3方面统计分析了滑坡灾害的发育现状;从地形地貌、地层岩性、地质构造、降雨、地震活动、人类工程活动等方面总结了滑坡灾害的形成条件,并提出防治对策与措施,力求有效地预防与减少滑坡灾害的发生。  相似文献   

小型水电站建设用地地质灾害评估技术研究——以湄尼多河小型水电站为例     

陈春华  李波 《中国地质灾害与防治学报》2006,17(3):133-136

现阶段,地质灾害评估技术人员在评估实践中,往往不注重各评估对象的差异性,采取同一评估模式,结果达不到评估的目的。在对小型水电站进行评估时,野外调查的重点,评估过程中所使用的方法以及危险性现状、预测及综合分区评估等与大型水电站、路线工程、矿山开采、民用建筑等工程有所不同。湄尼多河小型水电站工程位于云南省怒江州福贡县马吉乡境内,地质环境条件复杂,评估级别综合为二级。文章以该电站建设用地地质灾害危险性评估为例,对小型水电站建设用地地质灾害危险性评估的方法与理论进行探讨。  相似文献   

Phase Equilibria of the Lyngdal Granodiorite (Norway): Implications for the Origin of Metaluminous Ferroan Granitoids   总被引：2，自引：0，他引：2  

BOGAERTS  MICHEL; SCAILLET  BRUNO; AUWERA  JACQUELINE VANDER 《Journal of Petrology》2006,47(12):2405-2431

The Proterozoic (950 Ma) Lyngdal granodiorite of southern Norwaybelongs to a series of hornblende–biotite metaluminousferroan granitoids (HBG suite) coeval with the post-collisionalRogaland Anorthosite–Mangerite–Charnockite (AMC)suite. This granitoid massif shares many geochemical characteristicswith rapakivi granitoids, yet granodiorites dominate over granites.To constrain both crystallization (P, T, fO₂, H₂O in melt) andmagma generation conditions, we performed crystallization experimentson two samples of the Lyngdal granodiorite (with 60 and 65 wt% SiO₂) at 4–2 kbar, mainly at fO₂ of NNO (nickel–nickeloxide) to NNO + 1, and under fluid-saturated conditions withvarious H₂O–CO₂ ratios for each temperature. Comparisonbetween experimental phase equilibria and the mineral assemblagein the Lyngdal granodiorite indicates that it crystallized between4 and 2 kbar, from a magma with 5–6 wt % H₂O at an fO₂of NNO to NNO + 1. These oxidized and wet conditions sharplycontrast with the dry and reduced conditions inferred for thepetrogenesis of the AMC suite and many other rapakivi granitesworldwide. The high liquidus temperature and H₂O content ofthe Lyngdal granodiorite imply that it is not a primary magmaproduced by the partial melting of the crust but is derivedby the fractionation of a mafic magma. Lyngdal-type magmas appearto have volcanic equivalents in the geological record. In particular,our results show that oxidized high-silica rhyolites, such asthe Bishop Tuff, could be derived via fractionation of oxidizedintermediate magmas and do not necessarily represent primarycrustal melts. This study underlines the great variability ofcrystallization conditions (from anhydrous to hydrous and reducedto oxidized) and petrogenetic processes among the metaluminousferroan magmas of intermediate compositions (granodiorites,quartz mangerites, quartz latites), suggesting that there isnot a single model to explain these rocks. KEY WORDS: ferroan granitoids; crystallization conditions; experiments; Norway; Sveconorwegian; Bishop Tuff  相似文献