应重视选用芳烃演化参数评价高演化碳酸盐岩     

高志龙 《海相油气地质》1997,2(1):11-14

现被广泛应用的测定高演化碳酸盐岩成熟度指标的多项有机岩石学评价方法，各有其不同的局限性，应用效果并不理想。研究发现，可利用芳烃演化新参数来代替其它失效的分子参数来评价碳酸盐岩有机质。芳烃因其结构、组成的特殊性和稳定性，在高演化阶段与油气生成及煤源岩成熟度有着良好的相关性，具有成为高演化碳酸盐岩成熟度指标的基础。从生产实践的角度看，芳烃演化参数有特殊适用性及选取的可行性。  相似文献   

区域农业可持续发展指标体系及评估方法   总被引：22，自引：2，他引：22  

刘慧 《地理科学进展》1997,16(2):21-25

本文从区域农业可持续发展的基本概念和特点出发，论述了区域农业可持续发展与陆地系统科学相辅相成的辩证关系。并围绕食物保障度、生态稳定、农村经济发展和区域内部平衡四个区域农业可持续发展的基本目标，确定了区域农业可持续发展指标体系的基本框架和基本评估方法。  相似文献   

Ecosystem objectives to support the UK vision for the marine environment     

Rogers SI  Tasker ML  Earll R  Gubbay S 《Marine pollution bulletin》2007,54(2):128-144

European Maritime States already have commitments to protect species and habitats and maintain quality standards in coastal and offshore waters. These are a direct response to environmental legislation in Europe and commitments made to biodiversity conservation in OSPAR and at the World Summit on Sustainable Development. An integrated approach to management requires that these are consistent with the requirements for sustainable development, and include wider social considerations and active stakeholder participation. This review describes a hierarchical framework that incorporates the marine objectives and delivery statements of ecological, social and economic sectors. The framework leads from the UK's guiding principles for sustainable development, through visionary statements and strategic goals for high level delivery, to operational objectives and statements of action which deliver management. Parts of this hierarchy can already be populated for the UK, especially those at the higher levels. At the operational level, however, there is less clarity. The review shows that, despite some gaps, existing commitments for ecological components of the ecosystem are transparent and generally conform to this framework, due largely to high profile government funding of environmental protection and science and a single national vision for the marine environment. Specific objectives for six components of the ecosystem were developed; benthic habitats, seabirds and mammals, phytoplankton and zooplankton, fish, and physical/chemical quality of the water and atmosphere. The objectives included some that avoided limits and others that aimed to achieve targets, and for management to be effective it will be important to have a common understanding of how these can together be interpreted and made operational. In a review of 13 social and economic sectors, few provided a clear breakdown of objectives leading from a high level vision or a sustainable development principle. Six sectors did not have high level government targets for production or other measures of sectoral performance. Such commercial operations generally determine their own operational delivery targets based on market forces. Recent proposals in Europe to create an integrated framework for social, economic and environmental activities will need to carefully balance the development of a strong and competitive marine economy with existing international obligations to environmental protection.  相似文献   

秦巴地区土壤测量金异常含矿性标志特征及矿体定位估计     

王志海 《陕西地质》1991,(2)

本文在总结若干土壤测量金异常资料的基础上,提出了秦巴地区矿致土壤测量金异常的三条主要标志特征。通过对金元素在土壤中迁移扩散及沉淀条件的分析,建立了推算金矿(化)体与金异常浓集中心突出高值点相对位置的经验公式,并确定了各地形级次的经验系数和常数。经验公式在陕西省秦巴地区有一定的普遍性及实用价值。  相似文献   

Spatial prediction of categorical variables: the Bayesian maximum entropy approach   总被引：2，自引：3，他引：2  

P. Bogaert 《Stochastic Environmental Research and Risk Assessment (SERRA)》2002,16(6):425-448

 Being a non-linear method based on a rigorous formalism and an efficient processing of various information sources, the Bayesian maximum entropy (BME) approach has proven to be a very powerful method in the context of continuous spatial random fields, providing much more satisfactory estimates than those obtained from traditional linear geostatistics (i.e., the various kriging techniques). This paper aims at presenting an extension of the BME formalism in the context of categorical spatial random fields. In the first part of the paper, the indicator kriging and cokriging methods are briefly presented and discussed. A special emphasis is put on their inherent limitations, both from the theoretical and practical point of view. The second part aims at presenting the theoretical developments of the BME approach for the case of categorical variables. The three-stage procedure is explained and the formulations for obtaining prior joint distributions and computing posterior conditional distributions are given for various typical cases. The last part of the paper consists in a simulation study for assessing the performance of BME over the traditional indicator (co)kriging techniques. The results of these simulations highlight the theoretical limitations of the indicator approach (negative probability estimates, probability distributions that do not sum up to one, etc.) as well as the much better performance of the BME approach. Estimates are very close to the theoretical conditional probabilities, that can be computed according to the stated simulation hypotheses.  相似文献   

Probabilistic assessment of travel times in groundwater modeling     

Gómez-Hernández  J. J.  Wen  X. -H. 《Stochastic Environmental Research and Risk Assessment (SERRA)》1994,8(1):19-55

A Monte Carlo approach is described for the quantification of uncertainty on travel time estimates. A real (non synthetic) and exhaustive data set of natural genesis is used for reference. Using an approach based on binary indicators, constraint interval data are easily accommodated in the modeling process. It is shown how the incorporation of imprecise data can reduce drastically the uncertainty in the estimates. It is also shown that unrealistic results are obtained when a deterministic modeling is carried out using a kriging estimate of the transmissivity field. Problems related with using sequential indicator simulation for the generation of fields incorporating constraint interval data are discussed. The final results consists of 95% probability intervals of arrival times at selected control planes reflecting the original uncertainty on the transmissivity maps.  相似文献   

河北水晶屯金矿元素垂向分带序列及原生晕空间特征   总被引：2，自引：0，他引：2  

魏俊浩 《矿产与地质》1994,8(1):73-77

以河北崇礼水晶屯金矿为例，选择了与金矿化关系密切的１４种指标元素，分析研究了该矿床金的指示元素的垂向分带序列及原生晕的空间发育特征，并建立了该矿床综合地球化学原生晕模型。  相似文献   

用协同—指示克立格预测储层物性参数：以胜利油田罗家砂四上砾岩为例     

向晓丽  张玺 《矿物岩石》1999,19(3):65-68

指示克立格是一种非参数统计方法,它能在不舍弃特异值的条件下进行有效的空间估计,协同克立格以协同区域化变量的研究对象,充分考虑了变量空间相关性和变量间的统计相关性,有着单变量克立格法可可比拟的优点,因而,本文提出协同－指示克立格法这一方法,在指示克立格中考虑多变量的空间相关性和变量间的统计相关性,使指示克拉立格与协同克立格相互补充,模拟现实,提高预测精度,并以胜利油田罗家砂四上砾岩为例进行参数预测,  相似文献   

Assessing Uncertainty Associated with the Delineation of Geochemical Anomalies   总被引：2，自引：0，他引：2  

Costa  Joao Felipe  Koppe  Jair Carlos 《Natural Resources Research》1999,8(1):59-67

A pedogeochemical exploratory survey of gold deposits was carried out in the region of São Sepé (southernmost Brazil). The region comprises a predominantly metamorphosed belt of volcanoclastics, sediments, serpentinites, basalts, gabbros, chert, tuffs, and banded iron formation of the Proterozoic age. The anomalies were identified first by stream sediment heavy mineral survey at the regional scale of exploration. Once spatial continuity was modeled, ordinary block kriging was performed to generate geochemical maps. Indicator block kriging also was used as an alternative in analyzing and interpreting geochemical data. A novel approach is proposed, which combines both ordinary and indicator kriging for delineating geochemical anomalies. Probability maps proved to be appropriate for selecting new sites for further exploration. Gold anomalies in soils trending NE were well defined by geostatistical analysis and subsequently confirmed by drilling.  相似文献   

我国东部主要类型金矿床的找矿标志     

周达孙 《南方国土资源》1998,(1)

中国东部地区不同类型的金矿床中大多可见到Ａｕ、Ａｇ、Ｃｕ、Ｐｂ、Ｚｎ、Ａｓ、Ｈｇ及Ｍｏ等元素的异常,除Ｍｏ外,其它元素的异常与Ａｕ元素的异常为正相关。各类型矿床的异常元素组合、矿物组合及黄铁矿中微量元素的含量、氧硫同位素变化等均有一定的差异。成矿环境总的来说是富硅或富钙、贫氧的碱性环境。  相似文献