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Theoretical system of sandstone-Type uranium Deposits in Northern China

Journal of Earth science 2022年第2期33卷 257-277页

作者： Ru.s.i Jin Huajian Liu Xiaoguang Li Tianjin Centre China Geological SurveyTianjin 300170China Key Laboratory of uranium Geology China Geological SurveyTianjin 300170China

Many theoretical results on sandstone-type uranium mineralization in northern China obtained by the uranium research team of the Tianjin Center of geological survey in recent years are *** the source sink system of uranium-producing basins,sedimentary environment of uranium-bearing rock series,ore-forming fluid information,evolution of tectonic events,basin formation and development,we redefine and classify uranium orebodies,redox zoning,and ore-controlling structural *** then systematically propose a theoretical system of sandstone-type uranium deposits in northern *** conclude that sandstone-type uranium deposits in northern China are mainly found in sedimentary environments such as rivers,deltas,and alluvial fans in the Mesozoic and Cenozoic lowstand systems tract and in gray sandstone layers in the vertical redox *** orebodies are controlled by the tectonic slope belt,which is in the shape of a strip on the plane,and spreads in a layer or plate on the ***(u.s.and downs)tectonic movement triggers large-scale phreatic flow in the basin,which is the real driving force for controlling the ore-forming *** theoretical system of sandstone-type uranium deposits in northern China should be based on global tectonic movement and environmental changes and take into account factors such as basins as a unit to study mineralization background,ore concentration areas as objects to study mineralization,and the correlation between regional tectonic movement and metallogenic process as a breakthrough point to study tectonic events and metallogenic *** should also be based on different basin types to establish metallogenic *** innovative research results and ideas are summarized with the aim of promoting the continuous improvement of sandstone-type uranium mineralization theory in northern China.

关键词： theoretical system metallogenic background mineralization metallogenic model vertical(u.s.and downs)tectonic movement sandstone-type uranium deposits ore deposit geology

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Improving Land Resource Evaluation using Fuzzy Neural Network Ensembles

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Pedosphere 2007年第4期17卷 429-435页

作者： XuE Yue-Ju Hu Yue-Ming LIu.s.u-Guang YANG Jing-Feng CHEN Qi-Chang BAO shi-Tai College of Engineering South China Agricultural University Guangzhou 510642 （China）. College of Information South China Agricultural University Guangzhou 510642 （China） u.s. geological survey （usGs） Center for Earth Resources Observation and science （EROs） Sioux Falls South Dakota 57198 （USA）

Land evaluation factors often contain continuous-, discrete- and nominal-valued attributes. In traditional land evaluation, these different attributes are usually graded into categorical indexes by land resource experts, and the evaluation results rely heavily on experts＇ experiences. In order to overcome the shortcoming, we presented a fuzzy neural network ensemble method that did not require grading the evaluation factors into categorical indexes and could evaluate land resources by using the three kinds of attribute valu.s.directly. A fuzzy back propagation neural network （BPNN）, a fuzzy radial basis function neural network （RBFNN）, a fuzzy BPNN ensemble, and a fuzzy RBFNN ensemble were used to evaluate the land resources in Guangdong Province. The evaluation results by using the fuzzy BPNN ensemble and the fuzzy RBFNN ensemble were much better than those by using the single fuzzy BPNN and the single fuzzy RBFNN, and the error rate of the single fuzzy RBFNN or fuzzy RBFNN ensemble was lower than that of the single fuzzy BPNN or fuzzy BPNN ensemble, respectively. By using the fuzzy neural network ensembles, the validity of land resource evaluation was improved and reliance on land evaluators＇ experiences was considerably reduced.

关键词： back propagation neural network (BPNN) data types fuzzy neural network ensembles land resource evaluation radial basis function neural network (RBFNN)

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A Web-Based Application for Exploring Potential Changes in Design Peak Flow of us urban Areas Driven by Land Cover Change

Journal of Remote Sensing

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Journal of Remote sensing 2023年第1期3卷 125-137页

作者： Kul Khand Gabriel B.senay AsRC Federal Data solutions Contractor to U.S.Geological Survey(USGS)Earth Resources Observation and Science(EROS)CenterSioux FallsSD 57198USA u.s.geological survey(usGs)Earth Resources Observation and science(EROs)Center North Central Climate Adaptation Science CenterFort CollinsCO 80523USA

Floods have become increasingly prominent in recent decades causing devastating effects on lives and livelihoods *** tools to assess the drivers of floods,such as increasing urbanization,could help to minimize flood *** increases the design peak flow(maximum potential surface water flow from a precipitation event with an average probability of occurring once in a specific recurrence interval),which is a key information needed for designing stormwater management infrastructures such as culverts and storm sewers.A web-based application was developed to explore the potential changes(1985 to 2020)in design peak flow of urban areas across the conterminous united states driven by land cover *** results indicate a potential increase in design peak flow in urban areas up to 126.6% in 2020 compared to *** the total 3,535 study urban areas,about 80%(2,840)urban areas increased design peak flow,and about 19%(654)decreased design peak flow.A general pattern of increasing design peak flow was observed during 1985 to 2010,and decreasing pattern was observed during 2010 to 2020,primarily driven by respective increasing(decreasing)and decreasing(increasing)developed areas(croplands).The application provides crucial information by visualizing both spatial and temporal data that could be useful for decision-makers in developing and improving urban stormwater management plans and policies for efficient resource allocations and reducing flood risks.

关键词： storm flood floods

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Genesis of sandstone-type uranium deposits along the northern margin of the Ordos Basin,China

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Geoscience Frontiers 2020年第1期11卷 215-227页

作者： Ru.s.i Jin Xueming Teng Xiaoguang Li Qinghong si Wei Wang Tianjin Center China Geological SurveyTianjin 300170China Key Laboratory of uranium Geology China Geological SurveyTianjin 300170China

sandstone-type u mineral resources are among the important sources for nuclear *** u deposits in the Ordos Basin in China form part of the northern segment of the sandstone-hosted Central Asian uranium *** types of mineralizations are recognized in this basin:"phreatic permeable type"and"interlayer permeable type",both exhibiting features equivalent to roll-front ***"interlayer permeable type"is widely accepted as the dominant mineralization type for sandstone-type uranium deposits within large-scale basins,also designated as the"interlayer oxidation zone type",based on the horizontal color zoning model representing changing redox *** we synthesize data from several drill holes within the Ordos Basin,which suggest that major Mesozoic tectonic movements controlled the evolution of the sedimentary system in the *** tectonic movements contributed to the formation of three angular unconformities and four parallel unconformities as inferred from the stratigraphic *** addition,other features such as vertical color zoning,paleo-channel controlled tabular or lentoid ore bodies(without roll-type)and a group interlayer horizontal zoning of altered minerals are also *** stratigraphic analysis indicates that the Ordos Basin generally witnessed four cycles of water level variations during *** the variations,three high water level and three low water level events were *** characteristics imply that the Ordos Basin went through multiple arid to humid climatic evolutions during *** the newly documented features with some novel concepts on the hydrodynamic mechanism for supergene ore-forming fluids,we propose a metallogenic model which invokes the importance of tectonic movements and water level fluctuations to explain the genesis of uranium deposits along the northern margin of the Ordos Basin.

关键词： sequence stratigraphic analysis Hydrodynamic mechanisms Metallogenic model Tectonic history Ordos Basin

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Potential influence of wildfire in modulating climate-induced forest redistribution in a central Rocky Mountain landscape

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Ecological Processes 2017年第1期6卷 52-68页

作者： John L.Campbell Douglas J.shinneman Department of Forest Ecosystems and society Oregon State UniversityCorvallisORUSA u.s.geological survey Forest and Rangeland Ecosystem Science CenterBoiseIDUSA.

Introduction:Climate change is expected to impose significant tension on the geographic distribution of tree ***,tree species range shifts may be delayed by their long life spans,capacity to withstand long periods of physiological stress,and dispersal *** could theoretically break this biological inertia by killing forest canopies and facilitating species redistribution under changing *** investigated the capacity of wildfire to modulate climate-induced tree redistribution across a montane landscape in the central Rocky Mountains under three climate scenarios(contemporary and two warmer future climates)and three wildfire scenarios(representing historical,suppressed,and future fire regimes).Methods:Distributions of four common tree species were projected over 90 years by pairing a climate niche model with a forest landscape simulation model that simulates species dispersal,establishment,and mortality under alternative disturbance regimes and climate ***:Three species(Douglas-fir,lodgepole pine,subalpine fir)declined in abundance over time,due to climate-driven contraction in area suitable for establishment,while one species(ponderosa pine)was unable to exploit climate-driven expansion of area suitable for *** fire frequency accelerated declines in area occupied by Douglas-fir,lodgepole pine,and subalpine fir,and it maintained local abundance but not range expansion of ponderosa ***:Wildfire may play a larger role in eliminating these conifer species along trailing edges of their distributions than facilitating establishment along leading edges,in part due to dispersal limitations and interspecific competition,and future populations may increasingly depend on persistence in locations unfavorable for their establishment.

关键词： Forest disturbance Wildfire Climate change Central Rocky Mountains Climate niche species migration species distribution

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Tectonics induced switching of provenance during the Late Quaternary aggradation of the Indus River Valley, Ladakh, India

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Geoscience Frontiers 2019年第1期10卷 285-297页

作者： Ravish Lal H.s.saini N.C.Pant s.A.I.Mujtaba Department of Geology University of Delhi geological survey of India

The Indus River flows through Ladakh, one of the driest and coldest places on earth, in a tectonically active domain. Fluvial, glaciofluvial, lacustrine and debris dominated sequences represent the Late Quaternary sedimentary record along the river cou.s.. Karakoram Fault, a major crustal scaled feature reported to be active during the Quaternary, is associated with the Indus River drainage. Linkages between a major, active fault and deposits formed during the activity period of the fault are explored using heavy mineral deduced provenance and Optically stimulated Luminescence(OsL) *** deposits in a ~200 km long stretch of the Indus River have been examined for a ~80 ka period to decipher the climate linked aggradation history. Damming of the Indus River at ~79 ka and existence of the spituk Lake for >30 ka is demonstrated. using geology of the provenance in relation to the mineralogical attributes of the Quaternary deposits, the major drainage reorganization when the connection of the Tangtse Valley to the Indus was blocked, is inferred at ~73 ka. It is supported by the geologicalgeomorphological evidence. The study demonstrates the application of provenance linked mineralogy in terrestrial aggradation in a tectonically active region.

关键词： Karakoram Fault Indus Drainage reorganization Heavy minerals Aggradation

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Economic appraisal of shale gas resources, an example from the Horn River shale gas play, Canada

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Petroleum science 2015年第4期12卷 712-725页

作者： Zhuoheng Chen Kirk G.Osadetz Xuansha Chen geological survey of Canada university of Calgary ZLR Valeon

Development of unconventional shale gas resources involves intensive capital investment accompa- nying large commercial production uncertainties. Eco- nomic appraisal, bringing together multidisciplinary project data and information and providing likely economic outcomes for various development scenarios, forms the core of business decision-making. This paper uses a dis- counted cash flow （DCF） model to evaluate the economic outcome of shale gas development in the Horn River Basin, northeastern British Columbia, Canada. Through numerical examples, this study demonstrates that the use of a single average decline curve for the whole shale gas play is the equivalent of the results from a random drilling process. Business decision based on a DCF model using a single decline curve could be vulnerable to drastic changes of shale gas productivity across the play region. A random drilling model takes those drastic changes in well estimated ultimate recovery （EuR） and decline rates into account in the economic appraisal, providing more information useful for business decisions. Assuming a natural gas well-head price of s4/MCF and using a 10 % discount rate, the results from this study suggest that a random drilling strategy （e.g., one that does not regard well Eu.s., could lead to a negative net present value （NPV）; whereas a drilling sequence that gives priority to developing those wells with larger Eu.s.earlier in the drilling history could result in a positive NPV with various payback time and internal rate of return （IRR）. under a random drilling assumption, the breakeven price is s4.2/MCF with more than 10 years of payout time. In contrast, if the drilling order is strictly proportional to well Eu.s. the result is a much better economic outcome with a breakeven price below the assumed well-head price accompanied by a higher IRR.

关键词： Drilling order EuR Risk aversion - shalepetroleum resource

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Ordovician Proto-basin in south China and its Tectonic Implications: Evidence from the Detrital Zircon u-Pb Ages of the Ordovician in Central Hunan, China

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Acta Geologica sinica(English Edition) 2020年第6期94卷 2115-2133页

作者： ZHANG Jibiao NI Jingbo LIu Yanxue ZHANG Heng Bu Ling Institute of Geology Chinese Academy of Geological SciencesBeijing 100037China Beijing Institute of geological survey Beijing 102206China Hebei Regional geological survey Institute Hebei 050081China

Caledonian orogeny is another important tectonic event in south China Block after the breakup of the Rodinia *** a view to constrain the tectonic evolution and proto-basin in south China,this paper reports the geochemical and zircon u-Pb dating data of the Ordovician strata in central Hunan,south *** features and paleocurrent directions suggest that the lower Ordovician deposited in a passive continental margin basin with a provenance of quartzose components and showing an affinity with the Yangtze Block.u-Pb age data for 260 detrital zircons from upper Ordovician identify three major age populations as:900-1200 Ma,1400-1800 Ma and 2400-2700 *** detrital zircon age spectrum as well as the paleocurrent directions suggest that upper Ordovician deposited in a foreland basin and showing a close affinity with the Cathaysia *** is also suggest that the lower Ordovician continuously accepted the mineral from the Yangtze Block,whereas the provenance of the upper Ordovician sedimentary basin changed from the Yangtze Block to the Cathaysia *** change implies a tectonic movement,which caused the transformation of the proto-basin in the Hunan area in sCB from passive continental margin basin to foreland basin probably took place during late *** fact also demonstrate that the Caledonian orogeny in south China Block began no later than 453 Ma,and a new crustal evolution model is proposed.

关键词： u-Pb chronology Ordovician Proto-basin Caledonian orogeny south China

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A cellular automata downscaling based 1 km global land use datasets (2010–2100)

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science Bulletin 2016年第21期61卷 1651-1661页

作者：李雪草俞乐徐伊迪杨军宫鹏 Terry sohl Nicholas Clinton Wenyu Li Zhiliang Zhu Xiaoping Liu Ministry of Education Key Laboratory for Earth system Modeling Center for Earth System Science Tsinghua University Joint Center for Global Change studies u.s. geological survey Earth Resources Observation and Science (EROS) Center u.s. geological survey school of Geography and Planning and Guangdong Key Laboratory for Urbanization and Geo-simulation Sun Yat-sen University

Global climate and environmental change studies require detailed land-use and land-cover （LuLC） information about the past, present, and future. In this paper, we discu.s.a methodology for downscaling coarse-resolution （i.e., half-degree） future land use scenarios to finer （i.e., 1 km） resolutions at the global scale using a grid-based spatially explicit cellular automata （CA） model. We account for spatial heterogeneity from topography, climate, soils, and socioeconomic variables. The model uses a global 30 m land cover map （2010） as the base input, a variety of biogeographic and socioeconomic variables, and an empirical analysis to downscale coarse-resolution land use information （specifically urban, crop and pasture）. The output of this model offers the most current and finest-scale future LuLC dynamics from 2010 to 2100 （with four representative concentration pathway （RCP） scenarios--RCP 2.6, RCP 4.5, RCP 6.0, and RCP 8.5） at a 1 km resolution within a globally consistent framework. The data are freely available for download, and will enable researchers to study the impacts of LuLC change at the local scale.

关键词： LuLC modeling spatial downscaling RCP scenarios urban expansion

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Petrogenesis and Tectonic Implications of A-type Granites in Zhaheba in the East Junggar Region of Xinjiang,China:Evidence from Geochronology,Geochemistry and sr-Nd Isotopic Compositions

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Acta Geologica sinica(English Edition) 2022年第3期96卷 938-953页

作者： TANG Hejun MENG Guixiang Wu Zhenhan WANG Zhaolin DENG Zhen YAN Jiayong QI Guang XuE Ronghui Chinese Academy of geological sciences China Geological SurveyMinistry of Natural ResourcesBeijing 100037China sinoProbe Center Chinese Academy of Geological SciencesChina Geological SurveyMinistry of Natural ResourcesBeijing 100037China

The magma source,petrogenesis,tectonic setting and geochronology of the late Paleozoic A-type granites widely exposed in the Zhaheba area,East Junggar,have thus far not been well-constrained.A better understanding of these issu.s.will help to reveal the magmatic processes and continental growth of Central *** A-type granites in Zhaheba include the Ashutasi alkaline granites and the Yuyitasi syenogranites,which were emplaced at 321.5±4.8 Ma and 321.7±0.6 Ma,*** major rock-forming minerals are orthoclase,perthite,arfvedsonite and quartz,which exhibit the following principal geochemical characteristics of A2-type granites.(1)Their REE distribution curves each exhibit a‘V’-shaped pattern and a marked depletion in *** are rich in large-ion lithophile elements Rb,Th and u as well as high-field-strength elements Nb,Ta,Zr and Hf,but significantly depleted in Ba,sr,P and Ti.(2)Their(^(87)sr/^(86)sr)i valu.s.0.7021-0.7041),εNd(t)valu.s.4.57-5.16)and REE distribution patterns are in basic agreement with those of the Kalamaili A-type granite belt in East *** T DM2 valu.s.of the alkaline granites and syenogranites range from 661 to 709 *** A-type granites may be the products of upwelling asthenosphere-triggered partial melting of immature lower *** alkaline granites were late-stage products of crystallization and *** to the syenogranites,the alkaline granites are significantly lower in K_(2)O,Na_(2)O,Al_(2)O 3,FeO,MgO and CaO,but significantly higher in incompatible elements(e.g.,siO_(2),Rb,and sr).The magmatic crystallization temperatures of the syenogranites and alkaline granites are 874℃ and 819℃,*** their age gradually decreases(peak ages:322 Ma and 307 Ma,respectively),there is a gradual decrease in the T_(DM2)of the A-type granites and a gradual increase in theεNd(t)value from the ulungur belt to the Kalamaili belt in East *** study of A-type granites is therefore one of the keys to understandi

关键词： A-type granite Zircon u-Pb sr-Nd isotopes post-collision East Junggar

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