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1.
Principles of Probabilistic Regional Mineral Resource Estimation 总被引：1，自引：0，他引：1
Agterberg Frits 《地球科学》2011,36(2):189-200
Five principal sources of uncertainty in quantitative mineral resource estimation are listed and illustrated by means of a simple example (mosaic model) and a case history study for large copper deposits in the Abitibi area of the Canadian Shield. Abitibi copper potential originally was estimated on the basis of 1968 estimates of production and reserves totalling 3.12 Mt Cu. This prognostication now could be evaluated on the basis of 2008 copper production and reserves totalling 9.50 Mt Cu. An earlier hindsight study performed on the basis of 1977 data (totalling 5.23 Mt Cu) showed seven new discoveries occurring either in the immediate vicinities of known deposits or on broad regional copper anomalies predicted from the 1968 inputs. By 1977, the global geographic distribution pattern of large copper deposits in the Abitibi area had stabilized. During the next 30 years, new copper was essentially found close to existing deposits, much of it deeper down in the Earth's crust. In this paper, uncertainties associated with copper ore tonnage are analyzed by comparison of 2008 data with 1968 data using (a) log-log plots of size versus rank, and (b) lognormal QQ-plots. Straight lines fitted by least squares on these plots show that 1968 slopes provide good estimates of 2008 slopes but 1968 intercepts are much less than 2008 intercepts. In each linear log-weight versus log-rank plot, the slope is related to fractal dimension of a Pareto frequency distribution, and in a lognormal QQ-plot it is determined by logarithmic variance. The difference between 2008 and 1968 intercepts represents the increase in copper ore production and reserves from 1968 to 2008. The Pareto model fits actual copper and massive sulphides increase over the past 40 years better than the lognormal frequency distribution model for 10 km×10 km cells on favorable environments in the Abitibi area. 相似文献
2.
利用测井信息评价盐湖相烃源岩 总被引：1，自引：0，他引：1
盐湖相烃源岩富含膏、盐质成分,使其测井响应特征发生极大改变,给测井评价烃源岩带来困难。基于实测数据,分析了盐湖相烃源岩中普遍发育的纯泥岩、含膏(盐)泥岩和膏(盐)质泥岩有机碳含量的测井响应模式,发现纯泥岩和含膏(盐)泥岩TOC与AC和LogRt呈正比,与DEN呈反比,膏(盐)质泥岩TOC与DEN呈正比,与LogRt呈反比,并基于此建立了盐湖相烃源岩测井评价方法,即首先利用ΔGR区分岩性,再针对不同岩性建立TOC评价模型,最后根据实测S1+S2和TOC建立相关关系,就可以求取烃源岩的TOC和S1+S2。利用该方法对东营凹陷沙四下亚段烃源岩性质和展布进行分析,发现预测TOC与实测TOC吻合程度高,具有一定推广价值。 相似文献
3.
中国昆明地区岩溶洞穴洞口带苔藓植物研究 总被引：2，自引：1，他引：1
为了研究中国西南岩溶洞穴植物区系与生物多样性特征, 作者曾两次对云南昆明地区12个岩溶洞穴进行了野外考察和苔藓植物标本采集工作。其中含昆明市石灰岩洞穴1个, 石林县石灰岩洞穴5个和宜良县白云岩洞穴6个。根据采自12个岩溶洞穴洞口带的164件苔藓植物标本研究, 本文首次报道昆明地区洞穴苔藓植物10科18属25种。昆明地区洞穴中分布较多的苔藓植物科有丛藓科( Po ttiaceae) 5属8种,凤尾藓科( Fi ssidentaceae ) 1属4种,柳叶藓科( Amblystegiaceae ) 3 属3 种和青藓(Brachytheciaceae ) 2属3种。溶洞中较常见的4种苔藓植物种类是萤光苔类植物光苔Cyathodiumcavernarum Kunze ( 见于6个溶洞中) , 小凤尾藓Fissidens bryoides Hedw ( 见于4个溶洞中) , 橙色净口藓Gymnostonum calcareum Nees et Ho rsch (见于3 个溶洞中)和长叶扭口藓Tortella tortuosa( Hedw ) Limp ( 见于3个溶洞中)。野外观察表明,受洞穴弱光环境生态因子的限制, 昆明地区洞穴苔藓植物主要生长于洞穴洞口0～ 26m带范围内; 2种丛集型藓类植物, 橙色净口藓Gymnostonumcalcareum Nees et Horsch, 和钩喙净口藓G.recurvirost re Hedw 参与洞口带钟乳石或石笋钙华沉积。 相似文献
4.
《煤田地质与勘探》2021,49(3):1-7
The Deep Resources Exploration and Mining(DREAM) grant program, within the framework of The National Key Research and Development Program grants, is a pillar to implement China's science and technology strategy in the area of deep resources exploitation. To tackle the insufficient of theories and technologies for the 1000-meter-deep mining, a section of mining, covering the research of basic theories, general technologies and application demonstration, was arranged in the layout of DREAM under the principle of "whole chain design, integrated implementation". In the aspect of basic research, DREAM mainly focused on the deep rock mechanics and mining theory, such as the in-situ mechanical behavior of deep rock, deep high stress induction and energy regulation theory. For the general and key technologies, DREAM supported the research on the mine construction and hoisting, excavation, rock breaking, mining methods and mining safety according to the characteristics of coal and metal mines. For the demonstration application, taking green, safe and efficient as the starting point, DREAM aimed at the green, safe and high efficiency mining, and the demonstration and leading role projects such as the low-waste and high-efficiency back fill mining. Since 2016, 10 RD projects have been funded, and 122 institutional participants with a total budget of RMB 235 million from the central government and RMB 480 million from enterprises as well as local governments have been involved. It is expected that the mining section of DREAM would contribute to establishing the theory and technology system in the area of deep mining and promoting the ability of deep resource exploitation in China. 相似文献
5.
The Hekoulinchang Sn-Pb-Zn-Ag polymetallic deposit(20000 t Sn at 0.27%,236 t Ag at 122.89 g/t,15000 t Pb at 0.84%,and 38000 t Zn at 1.43%)is located in the Wandashan Terrane of the easternmost segment of the Central Asian Orogenic Belt.The timing of Sn-Pb-Zn-Ag polymetallic mineralization remains unclear due to a lack of precise isotope dating directly conducted on ore minerals.The authors herein report that the LA-ICP-MS U-Pb ages of cassiterite and zircon from the granite porphyry in the Hekoulinchang Sn-Pb-Zn-Ag polymetallic deposit are 101.4±7.9 Ma and 115.4±1.0 Ma,respectively,indicating that Sn mineralization and magmatism occurred during the Early Cretaceous.The granite porphyry belongs to the subalkaline series peraluminous I-type granites that are depleted in Nb,Ta,and Ti and enriched in Rb,Th,U,and Pb.TheεHf(t)values of the granite porphyry range from 0.9 to 7.4,with an average of about 5.6 and two-stage model ages(TDM2)of 705–1116 Ma,with an average age of 819 Ma.The εNd(t)values of the apatites are–1.60–0.45,with an average of–0.9,and two-stage model ages(TDM2)of 872–1040 Ma,with an average age of 983 Ma.The Nd-Hf isotope data indicate that the magma may have been derived from the partial melting of juvenile crustal material. 相似文献
6.
Basem Zoheir Richard Goldfarb Astrid Holzheid Hassan Helmy Ahmed El Sheikh 《地学前缘(英文版)》2020,11(1):325-345
The Um Rus tonalite-granodiorite intrusion(~6 km2)occurs at the eastern end of the Neoproterozoic,ENE-trending Wadi Muba rak shear belt in the Central Eastern Desert of Egypt.Gold-bearing quartz veins hosted by the Um Rus intrusion were mined intermittently,and initially by the ancient Egyptians and until the early 1900 s.The relationship between the gold mineralization,host intrusion,and regional structures has always been unclear.We present new geochemical and geochronological data that help to define the tectonic environment and age of the Um Rus intrusion.In addition,field studies are integrated with EPMA and LA-ICP-MS data for gold-associated sulfides to better understand the formation and distribution of gold mineralization.The bulk-rock geochemical data of fresh host rocks indicate a calc-alkaline,metaluminous to mildly peraluminous,I-type granite signature.Their trace element composition reflects a tectonic setting intermediate between subduction-related and within-plate environments,presumably transitional between syn-and post-collisional stages.The crystallization age of the Um Rus intrusion was determined by in situ SHRIMP 206 Pb/238 U and 207Pb/235U measurements on accessory monazite grains.The resultant monazite U-Pb weighted mean age(643±9 Ma;MSWD 1.8)roughly overlaps existing geochronological data for similar granitic intrusions that are confined to major shear systems and are locally associated with gold mineralization in the Central Eastrn Desert(e.g.,Fawakhir and Hangaliya).This age is also consistent with magmatism recognized as concomitant to transpressional tectonics(D2:~650 Ma)during the evolution of the Wadi Mubark belt.Formation of the gold-bearing quartz veins in NNE-SSW and N-S striking fault segments was likely linked to the change from transpressional to transtensional tectonics and terrane exhumation(D3:620-580 Ma).The development of N-S throughgoing fault arrays and dike swarms(~595 Ma)led to heterogeneous deformation and recrystallization of the mineralized quartz veins.Ore minerals in the auriferous quartz veins include ubiquitous pyrite and arsenopyrite,with less abundant pyrrhotite,chalcopyrite,sphalerite,and galena.Uncommon pentlandite,gersdorffite,and cobaltite inclusions hosted in quartz veins with meladiorite slivers are interpreted as pre-ore sulfide phases.The gold-sulfide paragenesis encompasses an early pyrite-arsenopyrite±loellingite assemblage,a transitional pyrite-arsenopyrite assemblage,and a late pyrrhotite-chalcopyrite-sphalerite±galena assemblage.Free-milling gold/electrum grains(10 sμm-long)are scattered in extensively deformed vein quartz and in and adjacent to sulfide grains.Marcasite,malachite,and nodular goethite are authigenic alteration phases after pyrrhotite,chalcopyrite,and pyrite and arsenopyrite,respectively.A combined ore petrography,EPMA,and LA-ICP-MS study distinguishes morphological and compositional differences in the early and transitional pyrites(PyⅠ,PyⅡ)and arsenopyrite(ApyⅠ,ApyⅡ).Py I forms uncommon small euhedral inclusions in later PyⅡand Apy II.PyⅡforms large subhedral crystals with porous inner zones and massive outer zones,separated by narrow As-rich irregular mantles.The Fe and As contents in PyⅡare variable,and the LA-ICP-MS analysis shows erratic concentrations of Au(<1 to 177 ppm)and other trace elements(e.g.,Ag,Te,and Sb)in the porous inner zones,most likely related to discrete sub-microscopic sulfide inclusions.The outer massive zones have a rather homogenous composition,with consistently lower abundances of base metals and Au(mean 1.28 ppm).The early arsenopyrite(Apy I)forms fine-grained euhedral crystals enriched in Au(mean 17.7 ppm)and many other trace elements(i.e.,Ni,Co,Se,Ag,Sb,Te,Hg,and Bi).On the other hand,ApyⅡoccurs as coarsegrained subhedral crystals with lower and less variable concentrations of Au(mean 4 ppm).Elevated concentrations of Au(max.327 ppm)and other trace elements are measured in fragmented and aggregated pyrite and arsenopyrite grains,whereas the undeformed intact zones of the same grains are poor in all trace elements.The occurrence of gold/electrum as secondary inclusions in deformed pyrite and arsenopyrite crystals indicates that gold introduction was relatively late in the paragenesis.The LAICP-MS results are consistent with gold redistribution by the N-S though-going faults/dikes overprinted the earlier NNW-SSE quartz veins in the southeastern part of the intrusion,where the underground mining is concentrated.Formation of the Um Rus intrusion and gold-bearing quartz veins can be related to the evolution of the Wadi Mubarak shear belt,where the granitic intrusion formed during or just subsequent to D2 and provided dilatation spaces for gold-quartz vein deposition when deformed by D3 structures. 相似文献
7.
Landslide susceptibility modeling based on ANFIS with teaching-learning-based optimization and Satin bowerbird optimizer 总被引：1，自引：0，他引：1
As threats of landslide hazards have become gradually more severe in recent decades,studies on landslide prevention and mitigation have attracted widespread attention in relevant domains.A hot research topic has been the ability to predict landslide susceptibility,which can be used to design schemes of land exploitation and urban development in mountainous areas.In this study,the teaching-learning-based optimization(TLBO)and satin bowerbird optimizer(SBO)algorithms were applied to optimize the adaptive neuro-fuzzy inference system(ANFIS)model for landslide susceptibility mapping.In the study area,152 landslides were identified and randomly divided into two groups as training(70%)and validation(30%)dataset.Additionally,a total of fifteen landslide influencing factors were selected.The relative importance and weights of various influencing factors were determined using the step-wise weight assessment ratio analysis(SWARA)method.Finally,the comprehensive performance of the two models was validated and compared using various indexes,such as the root mean square error(RMSE),processing time,convergence,and area under receiver operating characteristic curves(AUROC).The results demonstrated that the AUROC values of the ANFIS,ANFIS-TLBO and ANFIS-SBO models with the training data were 0.808,0.785 and 0.755,respectively.In terms of the validation dataset,the ANFISSBO model exhibited a higher AUROC value of 0.781,while the AUROC value of the ANFIS-TLBO and ANFIS models were 0.749 and 0.681,respectively.Moreover,the ANFIS-SBO model showed lower RMSE values for the validation dataset,indicating that the SBO algorithm had a better optimization capability.Meanwhile,the processing time and convergence of the ANFIS-SBO model were far superior to those of the ANFIS-TLBO model.Therefore,both the ensemble models proposed in this paper can generate adequate results,and the ANFIS-SBO model is recommended as the more suitable model for landslide susceptibility assessment in the study area considered due to its excellent accuracy and efficiency. 相似文献
8.
Huan-huan Yang Qin Wang Yan-bo Li Bin Lin Yang Song Yi-yun Wang Wen He Hong-wei Li She Li Jian-li Li Chang-cheng Liu Shi-bin Feng Tang Xin Xue-lian Fu Xin-juan Liang Qi Zhang Bei-qi Wang Yang Li 《China Geology》2022,5(1):136-159
The Tiegelongnan Cu(Au,Ag)deposit in central Tibet contains more than 10 Mt of copper ranking 29 th in the world.It is characterized by typical porphyry-epithermal alteration and mineralization.In order to improve the understanding of porphyry-epithermal copper deposit in Tibet,new zircon U-Pb age and sulfur isotope data along with published data in the Tiegelongnan are presented to investigate the formation and preservation mechanism.Ore-related intrusive rocks in the Tiegelongnan including Early Cretaceous(about 120 Ma)granodiorite porphyry and diorite porphyry are closely related to the northward subduction of Bangongco-Nujiang ocean.Sulfur mainly comes from deep magma,and ore-forming fluid is affected by both magmatic and meteoric water.The metallogenic setting of Tiegelongnan is consistent with those of Andean porphyry copper deposits in South America.The cover of the Meiriqiecuo Formation volcanic rocks,Lhasa-Qiangtang collision and India-Eurasian collision have significance in the preservation and uplift of the deposit.The formation,preservation and discovery of Tiegelongnan play an important role in exploration of ancient porphyry-epithermal deposits in Tibet. 相似文献
9.
There are abundant coal and coalbed methane(CBM)resources in the Xishanyao Formation in the western region of the southern Junggar Basin,and the prospects for CBM exploration and development are promising.To promote the exploration and development of the CBM resources of the Xishanyao Formation in this area,we studied previous coalfield survey data and CBM geological exploration data.Then,we analyzed the relationships between the gas content and methane concentration vs.coal seam thickness,burial depth,coal reservoir physical characteristics,hydrogeological conditions,and roof and floor lithology.In addition,we briefly discuss the main factors influencing CBM accumulation.First,we found that the coal strata of the Xishanyao Formation in the study area are relatively simple in structure,and the coal seam has a large thickness and burial depth,as well as moderately good roof and floor conditions.The hydrogeological conditions and coal reservoir physical characteristics are also conducive to the enrichment and a high yield of CBM.We believe that the preservation of CBM resources in the study area is mainly controlled by the structure,burial depth,and hydrogeological conditions.Furthermore,on the basis of the above results,the coal seam of the Xishanyao Formation in the synclinal shaft and buried at depths of 700-1000 m should be the first considered for development. 相似文献
10.
NING Chuanxiang MA Zhongliang JIANG Zhenxue SU Siyuan LI Tingwei ZHENG Lunju WANG Guozhen LI Fengxun 《《地质学报》英文版》2020,94(2):352-363
To reveal the effect of shale reservoir characteristics on the movability of shale oil and its action mechanism in the lower third member of the Shahejie Formation(Es3l), samples with different features were selected and analyzed using N2 adsorption, high-pressure mercury injection capillary pressure(MICP), nuclear magnetic resonance(NMR), high-speed centrifugation, and displacement image techniques. The results show that shale pore structure characteristics control shale oil movability directly. Movable oil saturation has a positive relationship with pore volume for radius > 2 μm, as larger pores often have higher movable oil saturation, indicating that movable oil is present in relatively larger pores. The main reasons for this are as follows. The relatively smaller pores often have oil-wetting properties because of organic matter, which has an unfavorable effect on the flow of oil, while the relatively larger pores are often wetted by water, which is helpful to shale oil movability. The rich surface provided by the relatively smaller pores is beneficial to the adsorption of immovable oil. Meanwhile, the relatively larger pores create significant pore volume for movable oil. Moreover, the larger pores often have good pore connectivity. Pores and fractures are interconnected to form a complex fracture network, which provides a good permeability channel for shale oil flow. The smaller pores are mostly distributed separately;thus, they are not conducive to the flow of shale oil. The mineral composition and fabric macroscopically affect the movability of shale oil. Calcite plays an active role in shale oil movability by increasing the brittleness of shale and is more likely to form micro-cracks under the same stress background. Clay does not utilize shale oil flow because of its large specific surface area and its block effect. The bedding structure increases the large-scale storage space and improves the connectivity of pores at different scales, which is conducive to the movability of shale oil. 相似文献
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12.
土压缩模量预测回归分析方法 总被引：1，自引：0，他引：1
在土压缩模量Es的分析计算中,常用的分析方法是根据土的e-p曲线试验资料建立公式求解,本文引入了数学上的回归分析方法来探讨Es与其它各项物理力学指标参数之间的相关关系,旨在找出对Es影响最显著的指标参数,并建立最优回归方程式,以此来预测Es。研究结果表明:该方法通用性强,应用范围广,亦可推广应用于其它相关领域。 相似文献
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14.
考虑核电厂地基-基础的动力相互作用,应用显式动力有限差分法分析了地震作用下极软岩、较软岩、坚硬岩上核电厂建筑结构基础的地震响应特征,比较了岩石坚硬程度对基础加速度反应谱的影响。研究表明：随着岩石坚硬程度的提高,核电厂建筑物结构基础的地震响应有增加的趋势;在周期轴上,基础处的加速度反应谱曲线会随着岩石坚硬程度的提高逐渐向短周期（高频段）方向移动。在高频段,建造于较坚硬岩石上基础结构的加速度反应谱值偏大;在中等频段,建造于较软岩石上基础结构的加速度反应谱值偏大;在低频段,岩石坚硬程度对加速度反应谱的影响不显著。 相似文献
15.
Ivan V. BRAGIN Georgy A. CHELNOKOV Oleg V. CHUDAEV Natalia A. KHARITONOVA Sergey V. VYSOTSKIY 《《地质学报》英文版》2016,90(1):276-284
Studied waters belong to warm(T=30-50℃),alkaline(pH=8.9-9.3),low mineralized(TDS235 mg/1)Na-HCO_3 or Na-SO_4-HCO_3 thermal waters with high content of SiO_2(up to 81 mg/l)and F(up to 3.9 mg/1),occur on modern volcano-tectonic rejuvenated areas of Eastern Sikhote-Alin orogenic belt.Low~3He concentration as well as N_2/O_2 and N_2/Ar ratios exclude influence of deep mantle fluid.New rare earth element data constrain our understandmg of water-rock interaction occurring in the water source region.Meteoric origin of waters is proved by stable isotope values varying from-71‰to-136.1‰and from-10.8‰to-18.8‰forδ~2U andδ~(18)O respectively.REE patterns reflect high pH,resultfing from water-rock interaction and oxidative conditions.Calculations of deep aquifer temperature using Na-K and quartz geothermometers show 116.8-131.1°C and 82.2-125.8℃respectively.Presence of deep faults both with abnormal thermal gradient(~45-50 K/km)define unique geochemical shape of thermal waters of Sikhote-Alin,area,where no present volcanic activity is registered. 相似文献
17.
Using the database of automatic hydrometeorological stations, installed in the Don RIver delta and Taganrog Bay seashore, the sources of the anomalois scale water negative surge and salinization of the Azov Sea under conditions of low river flow in 2015–2016 are studied. The new schemes of stratification and advection of salty sea waters in the Don River mouth under different weather conditions, water discharge and levels are given. 相似文献
18.
地震次生地质灾害风险评估集对态势分析 总被引：2，自引：0，他引：2
5．12四川汶川8级强震引发了大量次生地质灾害,加剧了灾情并严重影响抗震救灾。地震次生地质灾害受多重因素制约,其孕育与致灾过程具有不确定性。利用集对分析原理与方法,对地震次生地质灾害进行同异反态势分析,拟定了风险评估的集对分析同一度、差异度、对立度等指标体系的构建原则与赋值标准,对承灾体系统的不确定性及其作用作了刻画与分析,建立了不同风险分区代表性的集对分析联系度表达式,为地震灾害研究提供了可资借鉴的新思路和技术方法。 相似文献
19.
下扬子区三叠纪古地理演化 总被引：2，自引：2，他引：0
下扬子区在三叠纪期间接受了早-中三叠世海相碳酸盐沉积、中-晚三叠世海陆交互相和陆相湖沼沉积.沉积相带的空间分布和古地理格局的变迁明显地受到区域构造的控制.区内盆地发育与演化是在华南板块与扬子板块、扬子板块与华北板块相互作用的背景下进行的.早-中三叠世末期的印支运动是下扬子区构造-古地理格局改变的决定性因素,使下扬子海盆闭合,沉积类型由海相沉积变为陆相沉积.下扬子区三叠纪古地理的演化特征也为板块碰撞提供了沉积证据. 相似文献