Principles of Probabilistic Regional Mineral Resource Estimation

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.      

Geology and mineralization of the Tiegelongnan supergiant porphyry-epithermal Cu (Au,Ag) deposit (10 Mt) in western Tibet,China: A review

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.     

Carbon cycle variability in tropical Atlantic across two Early Eocene hyperthermals

Early Eocene hyperthermals are geologically short-lived global warming events and represent fundamental perturbations to the global carbon cycle and the Earth’s ecosystem due to massive additions of isotopically light carbon to the ocean-atmosphere system.They serve as ancient analogs for understanding how the oceanic carbonate system and surface-ocean ecosystem would respond to ongoing and future climate change.Here,we present a continuous carbonate record across the Eocene Thermal Maximum 2(ETM2 or H1,ca.54.1 Ma)and H2(ca.54 Ma)events from an expanded section at Ocean Drilling Program Site 1258 in tropical Atlantic.The abundant calcareous nannofossils and moderate carbonate content throughout the studied interval suggest this record was deposited above the calcite compensation depth(CCD),but below the lysocline and under the influence of terrestrial dilution.An Earth system model cGENIE is used to simulate the carbon cycle dynamics across the ETM2 and H2 to offer insights on the mechanism of the rapid warming and subsequent recovery in climate and ecosystem.The model suggests moderate changes in ocean pH(0.1–0.2 unit)for the two scenarios,biogenic methane from a rechargeable methane capacitor and organic matter oxidation from thawing of the permafrost.These pH changes are consistent with a recent independent pH estimate across the ETM2 using boron isotopes.The carbon emission flux during the ETM2 is at least an order of magnitude smaller than that during the Paleocene–Eocene Thermal Maximum(PETM)(0.015–0.05 Pg C yr^-1vs.0.3–1.7 Pg C yr^-1).The comparable pre-and post-event carbonate contents suggest the lysocline did not over deepen following the ETM2 at this tropical Atlantic site,indicating spatial heterogeneity in the carbonate system due to strong dilution influence from terrestrial weathering and riverine discharge at Site 1258.     

Geochronological and geochemical constraints on the petrogenesis of late Mesoproterozoic mafic and granitic rocks in the southwestern Yangtze Block

Late Mesoproterozoic igneous rocks in the SW Yangtze Block are important for understanding the role of it in reconstruction of the Rodinia supercontinent.In the present study,we report new geochronological,geochemical,and Nd-Hf isotopic data for the Cuoke plagioclase amphibolites and granites in the SW Yangtze Block.Geochronological results show that the plagioclase amphibolites and granites have similar late Mesoproterozoic zircon U-Pb ages of 1168-1162 Ma,constituting a bimodal igneous assemblage.The plagioclase amphibolites have high and variable TiO2 contents(1.15-4.30 wt.%)and Mg#(34-66)values,similar to the tholeiitic series.They are characterized by enrichment in LREEs and LILEs,and have OIB-like affinities with positive Nb and Ta anomalies.The plagioclase amphibolites have positive whole-rockεNd(t)(+3.2 to+4.3)and zirconεHf(t)(+4.3 to+10.7)values,indicating that they were derived from an OIB-like asthenospheric mantle source.The granites belong to the reduced peralkaline A-type series and have negativeεNd(t)value of-6.0 andεHf(t)values of-5.8 to-13.8,indicating a derivation from the partial melting of ancient mafic lower crust.In combination with the~1.05-1.02 Ga bimodal igneous assemblage in the SW Yangtze Block,we propose that the Cuoke 1168-1162 Ma igneous rocks were likely formed in a continental rift basin and argue against the existance of Grenvillian Orogen in the SW Yangtze Block during the late Mesoproterozoic.     

Analysis of prospecting polymetallic metallogenic belts by comprehensive geophysical method

This paper is based on the analysis and research on the silver-lead-zinc polymetallic ore in New Ballyhoo Banner in southern Manzhouli of Inner Mongolia.Because metal mineralization brings rock formations,the geophysical features such as low resistivity,high polarization rate and uneven distribution of magnetization,the comprehensive geophysical methods are adopted including high-precision magnetic measurement,high-power induced polarization,IP field middle gradient and controlled source audio-frequency magnetotellurics.In the survey work of multi-metal ore deposits,from surface sweeping to single point measurement,and from single point to section going deeper layer by layer,the resolution of measurement is continuously improved,and various geophysical methods support and complement each other,so explorers can successfully predict the direction,scale and volume of the metallogenic belts in conjunction with geochemical exploration,geological survey and drilling.It has provided a strong basis for completing the exploration task of predicting the reserve volume of ore bodies.The research conclusions of this exploration case have thus a high reference value in the same type of exploration work.     

利用Grapher绘制彩色渐变剖面平面图

在物探扫面工作中,有大量的剖面数据需要绘制成剖面平面图,要求寻找一个高效快速的制图方法.通过对Grapher 自动化功能的分析和实践,编制程序实现了快速绘制彩色渐变剖面平面图的需求,说明利用自动化脚本能够在获得精美图件的同时,可以极大地提高作图效率.     

冷生风化作用对边坡稳定性影响

The experiment shows that considerable influence on density rock properties are subjected by nival weathering conditions. The main parameter defining the rock suitability for solution various engineering and geological problems is its firmness limit on single axis pressing. The firmness properties of sandstone being in absolutely dry condition for Kabakta suite at the beginning of investigation was 64.7 MPa, for Nerungri suite sandstones it was 48. 7 MPa. The investigations showed how much the nival conditions of cryohypergenesis of rock sandstones in Kabakta and Nerungri suites have destructive influence in comparison with aquale and more over aerale conditions. In the aerale conditions sedimentary rock firmness of Kabakta suite decreased to 23.2 MPa, in aquale conditions to 16.5, and in the nivale conditions to 8.9 MPa. In Nerungri suite sandstones are according to 17.7 MPa, 11.1 MPa, and 6 MPa after 300 freezing and thawing cycles. The common sandstone firmness decrease of Kabakta suite was 25 %,of Nerungri suite it was 23.8%. Marlstone samples after 400 FTC decrease to 62% in the nivale conditions and to 33 % in the aerale conditions. After 3～5 years of exploitation marlstone will destruct due to structural and textural inhomogenesis up to gruss, i.e. it will not meet the requirements of durability.Judging by the results of carried out experiment it should be concluded that by cryogenic weathering the sedimentary rocks (sandstones) and rocks with schistose lithogenic texture (marlstone) are subjected to disintegration. The primary rock samples firmness considerably influences on the disintegration rate.     

《同一个地质计划》的进展与对策

《同一个地质计划（OneGeology）》最初由英国地质调查局于2006年2月提出,已得到全球地学组织的支持。到2007年底,国际地球科学联合会等10个全球学术团体与国际地学组织、2个跨国公司、2位知名人士和67个国家的地质调查局参加了该计划。《同一个地质计划》是各个国家的地质调查局贡献给国际行星地球年的、约1：100万比例尺的、可在网络上很容易取得最好世界地质图数据的计划。该计划的目标是：使可用的地质图数据能被更多的人使用,使需要的人受益,促进互操作能力的增强。《同一个地质计划》的实施,可以提升全球、大陆、行星、海洋地球科学图的编制和出版的合作能力。深化对一些地区地质问题的研究,并可作为国际地球行星年一个切实可用的成果,提升国家地质调查局的形象;运用管理地学知识的领导能力和经验,通过教育、科学、文化和交流。能够处理全球污染对社会、经济和环境的影响问题。促进全球环境保护公约的执行,减缓自然灾害,使全球经济可持续发展,人们的居住环境更安全、更繁荣。精神生活更丰富、更快乐。因此,实施该计划不仅有现实意义,更有重要而深远的政治意义。     

Cenozoic Sea‐land Transition and its Petroleum Geological Significance in the Northern South China Sea

The process of Cenozoic sea-land changes in the northern South China Sea(SCS)controlled the sedimentary filling pattern and played an important role in the petroleum geological characteristics of the northern marginal sedimentary basins.Under the control of the opening process of the SCS,the northern SCS Cenozoic transgression generally showed the characteristics of early in the east and late in the west,and early in the south and late in the north.The initial transgression occurred in the Eocene in the Taixinan Basin(TXNB)of the eastern SCS,while the transgression occurred until the Pliocene in the Yinggehai Basin(YGHB)of the western SCS.International Ocean Discovery Program(IODP)expeditions(Expeditions 367/368)revealed that the initial transgression of the SCS basin occurred at approximately 34 Ma,which was the initial opening time of the SCS.The period of drastic changes in the sedimentary environment caused by large-scale transgression corresponded to the opening time of the southwestern subbasin(approximately 23 Ma),which also represented the peak of the spreading of the SCS.The sea-land transition process controls the distribution of alternating continent-marine facies,marine facies source rocks and reservoirs in the basins.The marine facies source rocks of the basins in the northern SCS have a trend of gradually becoming younger from east to west,which is consistent with the regional process of gradual transgression from east to west.Regional sea-level changes were comprehensively influenced by SCS opening and global sea-level changes.These processes led to the early development in the east and south and late development in the west and north for the carbonate platform in the SCS.Carbonate platforms form another type of"selfgenerating and self-accumulating"oil-gas reservoir in the northern SCS.The sea-land transition controlled the depositional filling patterns of different basins and laid the foundation of marine deposits for oil and gas resources.The source-reservoircap assemblage in the northern SCS was controlled horizontally by provenance supply and sedimentary environmental changes caused by sea-land transition and vertically by the tectonic evolution of the SCS and regional sea-level changes.     

Geochemical Characterizations of Source and Depositional Environment of Hydrocarbons in the Lake Albert Rift Basin

Despite the upsurge in hydrocarbon exploration in the Lake Albert Rift Basin(LARB)over the past three decades,systematic characterization of hydrocarbon compositions remains lacking,leading to uncertainties in source rock and oil generation determination.We characterized crude oil compositions and oil sand samples in the northern and southern subbasins of LARB.The relative abundance of normal and branched linear alkanes,hopanes,steranes,and aromatic hydrocarbon suggest that northern and southern hydrocarbons were deposited in anoxic to suboxic lacustrine environments and share similar biological source compositions(i.e.,a mixture of plants and aquatic algae and bacteria).Relative to southern samples,northern samples show more negative δ¹³C values for oils,saturates and aromatics,indicating longer migration paths,and exhibit higher MPI-1,DNR-1 and 4-/1-MDBT ratios,indicating higher maturity.Between the two possible sets of source rocks(upper Miocene and Jurassic strata),the positive δ¹³C values of saturated hydrocarbons(average=-20.5‰)suggest that the upper Miocene lacustrine shale is the most likely candidate.Oleanane index(<5% in our samples)does not exclude either source rock possibility,and C₂₈/C₂₉ regular sterane(average=0.63)may be biased by high terrestrial inputs in a lacustrine setting.Together,our data show that northern and southern oils originate from the same source rocks but different oil kitchens.Given the similar geochemical characteristics of southern and northern oils,previous exploration successes in the northern subbasin likely suggest similar potential in the southern sector,while other elements influencing exploration success must be also evaluated.     

大直径桩承载特性的研究进展评述

从大直径桩的荷载传递特性、在竖向荷载作用下承载特性的试验和理论、在水平向荷载作用下承载特性的试验和理论方面评述大直径桩承载特性的研究进展。同时指出各种研究中存在的问题,以及各种研究方法的优点和不足。     

ROLE OF STUDIES OF STRUCTURES OF ORE DEPOSITS AND PHYSICOMECHANICAL PROPERTIES OF ROCKS IN DETERMINING CONDITIONS OF LOCALIZATION OF ENDOGENIC ORES

Tectonic variables, chemical composition and physical properties of rocks such as porosity, plasticity, and elasticity, predetermine positions and shapes of endogenic ore bodies to a highly significant degree. A detailed analysis of these relationships, even in its present beginning stage, is often conducive not only to a better insight into origins of ores, but also to reducing prospecting risks in the field. --V. P. Sokoloff.     

齐Ⅰ金矿床石英热发光研究

通过对石英热发光特征研究,发现石英热发光曲线的复杂与否,与矿床的形成深度、多期次成矿作用和矿化的贫富有一定的关系。进而,为在该区进一步深入找矿及寻找其它内生矿床提供一项新的研究途径。     

高速公路软土地基处理方法评价

沿河、沿湖地区高速公路的建设,不可避免地要涉及到对软土地基的处理,而软基路段往往是制约工期和造价的主要因素之一。文中具体分析沿江、沿湖地区高速公路软土特征,对排水固结、堆(超)载预压、水泥搅拌桩复合水泥粉煤灰碎石桩等常用软基处理方法进行评价。     

断裂多期活动及其研究意义

本文从断层多期活动的客观存在出发,在理论和实验两个方面论述了断层多期活动的必然性,并提出了对断裂多期活动研究的方法、途径和意义。      

三组结构面状态下不同产状结构面的力学效应研究

本文分析了三组结构面产状模型力学实验结果, 揭示了这种组合条件岩体中产生压剪区、张剪区及结构面、结构体的多种变形成分, 也揭示了压剪区和张剪区形成机理、及三组结构面组合下结构面产状的力学效应。     

导水裂隙带高度探测新方法综述

确定导水裂隙带高度的方法主要有两类：一类是实际探测法；另一类是理论计算和经验公式计算法。随着科技技术的发展，近年来又产生和发展了许多新的探测技术和方法。本文主要介绍了几种探测新方法的工作原理和方法，并对其进行了分析比较。为准确地探测导水裂隙带高度，实际应用中应根据实际情况具体分析，合理地选择探测方法和手段。     

青藏高原西北部干旱荒漠区表生地球化学研究

较系统地研究了青藏高原西北部干旱荒漠景观风成沙、土壤及水系沉积物表生介质元素表生地球化学特征.研究了风成沙、水系沉积物的粒级组成、颗粒成分、元素含量变化及三者的关系.研究了土壤各发生层元素的分布规律,以钙积层为主碱性障对元素迁移和富集贫化的影响.上述基础性研究为化探方法技术的制定奠定了基础.     

安徽省观赏石资源开发利用研究

观赏石是一种可开发利用的经济矿产资源,安徽复杂的地质背景造就了丰富多样的观赏石资源,为了合理开发和利用安徽的观赏石资源,本文对安徽观赏石资源的品种、分布、开发利用现状与前景、存在的主要问题进行了初步研究,并提出合理开发和利用观赏石资源的建议.     

有关《中国古地理图》的点滴追忆

The Atlas of Palaeogeography of China was published in 1955. This paper will introduce the impor- tant historical background of the compilation and publishing of the atlas. Actually it was a direct outcome of the famous Main geological structural units of China written by Huang Jiqing in 1945. Confined by the status of geological development of that stage, the atlas mainly presents the variation of the distribution of old landmasses and oceans during different geological stages. The compilation was based on facies types, palaeontological species , and features of regional fauna assemblages . The basic scale of the atlas was 1:1 000 000. There are totally 20 maps, spanning from the Sinian to Triassic of the Mesozoic. The compila-tion was finished in more than three years. The outline of landmasses and oceans, main direction of trans-gression and regression, distribution of fossils, crustal deformation, mineral deposits, as well as volcanic and glacial activities are shown with various patterns and colors