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21.
藏北南羌塘盆地毕洛错地区下侏罗统曲色组石膏岩层 总被引:1,自引:0,他引:1
对西藏自治区北部南羌塘盆地毕洛错地区下侏罗统曲色组石膏岩层进行了研究。根据岩石地层和生物地层资料,确认毕洛错地区的石膏岩层和油页岩为曲色组的一部分,地质时代为早侏罗世,并确认下侏罗统曲色组在区域上可能是寻找油气、油页岩资源的重要层位之一。 相似文献
22.
鱼卡煤田大煤沟组高分辨率层序地层特征及聚煤规律 总被引:1,自引:0,他引:1
利用高分辨率层序地层学理论和技术方法,综合地震、测井、岩芯和煤质资料对柴达木盆地北缘鱼卡煤田中下侏罗统大煤沟组地层河湖三角洲沉积体系进行高分辨率层序地层学分析,从中识别出短期、中期、长期3个级别的基准面旋回层序,划分出向上"变深"非对称型、向上"变浅"非对称型及对称型3种短期基准面旋回基本结构类型。依据等时地层对比法则进行不同级次基准面旋回层序的联井对比,建立了大煤沟组的等时地层格架,在等时地层格架内进行了煤层对比,并在等时地层格架内分析了聚煤规律。 相似文献
23.
24.
柴达木盆地北缘侏罗系不同沉积环境烃源岩生物标志物特征及其应用 总被引:2,自引:0,他引:2
柴达木盆地北缘地区侏罗系(中下侏罗统)的优质烃源岩主要发育于湖相与三角洲相环境。研究了不同时代、不同沉积环境中烃源岩的生物标志物组成特征,结果发现,有3类化合物的分布与组成差异显著,包括三环萜烷(C19、C20、C21)的分布型式、重排藿烷的丰度以及规则甾烷的相对组成。其中,不同时代的差异主要体现在规则甾烷组成上;而不同沉积环境的差异主要体现为三环萜烷(C19、C20、C21)的分布型式及重排藿烷的丰度。分析认为,这些差异与烃源岩的沉积环境及其生源组成有密切关系。据此,初步将这些参数应用于两方面研究,一是为划分地层沉积环境提供“生物标志物相标志”,二是研究油源对比,取得良好效果。因此,本文研究结果具有重要实用价值与参考意义。 相似文献
25.
The uptake and release of trace metals (Cu, Ni, Zn, Cd, and Co) in estuaries are studied using river and sea end-member waters
and suspended particulate matter (SPM) collected from the Changjiang Estuary, China. The kinetics of adsorption and desorption
were studied in terms of environmental factors (pH, SPM loading, and salinity) and metal concentrations. The uptake of the
metals studied onto SPM occurred mostly within 10 h and reached an asymptotic value within 40 h in the Changjiang Estuary.
As low pH river water flows into the high pH seawater and the water become more alkaline as it approaches to the seaside of
estuary, metals adsorb more on SPM in higher pH water, thus, particulate phase transport of metal become increasingly important
in the seaward side of the estuary. The percentage of adsorption recovery and the distribution coefficients for trace metals
remained to be relatively invariable and a significant reduction only occurred in very high concentrations of metals (>0.1 mg L−1). The general effect of salinity on metal behavior was to decrease the degree of adsorption of Cu, Zn, Cd, Co, and Ni onto
SPM but to increase their adsorption equilibrium pH. The adsorption–desorption kinetics of trace metals were further investigated
using Kurbatov adsorption model. The model appears to be most useful for the metals showing the conservative behavior during
mixing of river and seawater in the estuary. Our work demonstrates that dissolved concentration of trace metals in estuary
can be modeled based on the metal concentration in SPM, pH and salinity using a Kurbatov adsorption model assuming the natural
SPM as a simple surfaced molecule. 相似文献
26.
Doline probability map using logistic regression and GIS technology in the central Ebro Basin (Spain) 总被引:3,自引:0,他引:3
In the surroundings of Zaragoza, karstification processes are especially intense in covered karst areas where fluvial terraces
lie directly on Tertiary evaporites. Since the beginning of Quaternary, these processes have lead to the development of collapse
and subsidence dolines with a wide range of sizes, which have significant economic impacts. To reduce economic impact and
increase safety, a regional analysis of this phenomenon is needed for spatial management. Therefore, a probability map of
dolines was developed using logistic regression and geographic information system (GIS) techniques. This paper covers the
selection of input data, manipulation of data using the GIS technology, and the use of logistic regression to generate a doline
probability map. The primary variable in the doline development in this area is geomorphology, represented by the location
of endorheic areas and different terrace levels. Secondary variables are the presence of irrigation and the water table gradient. 相似文献
27.
Zaragoza city is located in the central Ebro Basin, in the Iberian Peninsula. The fluvial terraces formed by the Ebro River
present a valuable resource of sand and gravel deposits. However, taking advantage of these available resources implies conflicts
with other land use interests like urban and industrial development as well as agricultural use, which has also traditionally
occupied the alluvial terraces. These deposits represent a substantial groundwater resource that should be preserved for future
generations. The development of spatial decision support systems (SDSS) has greatly assisted efforts for solving land-use
conflicts. These systems combine the benefits of geographic information systems (GIS) and decision support methodologies and
are therefore suitable to manage sustainable development of urban areas. In this contribution, an extraction suitability map
taking into consideration a variety of environmental criteria is created with the help of a SDSS. The method used is the analytical
hierarchy process which is integrated in ArcGIS. Areas most suitable to sand and gravel extraction are located in the high
terraces, and in those terraces covered by pediments where the thickness of resource is relatively high. These areas are far
from valuable natural areas, outside areas most vulnerable to groundwater contamination, and beneath soils with poor irrigation
characteristics. 相似文献
28.
Gary Bridge 《Geoforum》2008,39(4):1570-1584
This paper explores the radical possibilities of pragmatism for geography using the illustration of arguments concerning a renewed (urban) public realm through the exchange of validity claims in communication. Pressing further the pragmatist possibilities of Habermas’s idea of communicative action it draws on John Dewey’s work, and a range of contemporary pragmatist philosophers, to consider human communicability in its widest sense. This is then explored using an example of the spatiality and performativity of body-minds in a range of communicative spaces of the city. Then the paper moves on to consider the radical implications of pragmatism for geography in general in terms of body-mind/environment relations; a transactional view of space; experience, rationality and radical democracy. 相似文献
29.
M. Beatriz Aguirre-Urreta Pablo J. Pazos Darío G. Lazo C. Mark Fanning Vanesa D. Litvak 《Journal of South American Earth Sciences》2008,26(1):91-99
A high-resolution ion-microprobe (SHRIMP) U–Pb zircon age from a tuff layer intercalated in the ammonoid bearing sedimentary succession of the Neuquén Basin in Argentina provides a robust geochronologic date to add to the absolute ages and to improve the relative chronology of the Early Cretaceous Hauterivian stage. The tuff layer appears interbedded between shales of the upper member (Agua de la Mula) of the Agrio Formation within the Spitidiscus riccardii ammonoid zone (base of the Late Hauterivian) yielding a date of 132.5 ± 1.3 Ma. This date confirms and supports an accurate correlation between the ammonoid biostratigraphy of the Neuquén Basin with the Western Mediterranean Province of the Tethys during the Early Cretaceous and matches with the most recently published time scale. It also casts doubts on the validity of K–Ar ages on glauconite-grains recently reported from the Lower Cretaceous of the Vocontian Basin of France. 相似文献
30.
Quantitative sinkhole hazard assessments in karst areas allow calculation of the potential sinkhole risk and the performance
of cost-benefit analyses. These estimations are of practical interest for planning, engineering, and insurance purposes. The
sinkhole hazard assessments should include two components: the probability of occurrence of sinkholes (sinkholes/km2 year) and the severity of the sinkholes, which mainly refers to the subsidence mechanisms (progressive passive bending or
catastrophic collapse) and the size of the sinkholes at the time of formation; a critical engineering design parameter. This
requires the compilation of an exhaustive database on recent sinkholes, including information on the: (1) location, (2) chronology
(precise date or age range), (3) size, and (4) subsidence mechanisms and rate. This work presents a hazard assessment from
an alluvial evaporite karst area (0.81 km2) located in the periphery of the city of Zaragoza (Ebro River valley, NE Spain). Five sinkholes and four locations with features
attributable to karstic subsidence where identified in an initial investigation phase providing a preliminary probability
of occurrence of 0.14 sinkholes/km2 year (11.34% in annual probability). A trenching program conducted in a subsequent investigation phase allowed us to rule
out the four probable sinkholes, reducing the probability of occurrence to 0.079 sinkholes/km2 year (6.4% in annual probability). The information on the severity indicates that collapse sinkholes 10–15 m in diameter
may occur in the area. A detailed study of the deposits and deformational structures exposed by trenching in one of the sinkholes
allowed us to infer a modern collapse sinkhole approximately 12 m in diameter and with a vertical throw of 8 m. This collapse
structure is superimposed on a subsidence sinkhole around 80 m across that records at least 1.7 m of synsedimentary subsidence.
Trenching, in combination with dating techniques, is proposed as a useful methodology to elucidate the origin of depressions
with uncertain diagnosis and to gather practical information with predictive utility about particular sinkholes in alluvial
karst settings: precise location, subsidence mechanisms and magnitude, and timing and rate of the subsidence episodes. 相似文献