湖南安化金矿床土壤地球化学异常特征及其意义

湖南安化金檀金矿区位于大神山岩体东面,具备较好的找金潜力。矿区Au、Sb、As等多元素异常发育,异常强度大,且各元素异常分布具较好的吻合性。矿区As、Sb等成矿指示元素中以As指示性最强,和Au的伴生关系最明显。岩浆活动与构造运动为区内成矿作用供应了物质来源和动力学基础,断裂带与断裂交汇部位是成矿元素的有利富集区域。结合矿区成矿地质条件和本次土壤地球化学元素组合特征和异常特征,认为矿区成矿属中低温变质热液成因。对金檀矿区的找矿标志进行了初步总结,为该区进一步地质找矿提供参考。     

基于证据权法的安徽东溪金矿大比例尺成矿预测与评价

应用GIS技术结合地质、地球物理、地球化学等资料进行综合信息成矿预测是目前找矿的趋势。以霍山县东溪金矿及外围1∶10 000大比例尺地区为研究对象,在野外地质调查的基础上,结合空间位置统计结果和矿区成矿特征,利用GIS平台提取地质、地球物理、地球化学等多元地质找矿信息,建立矿区找矿预测模型。选择符合条件的独立预测因子作为证据图层,以5m×5m为网格单元,分析各证据图层与矿体空间分布关系。运用证据权法对矿区及外围进行成矿预测,通过图形方式直观表达成矿高概率的空间分布,对圈定的找矿靶区进行综合评述。研究区找矿靶区内地质、物探、化探找矿信息良好,各靶区内均有较好的金矿化信息。     

嫩江县花朵山区土壤地球化学异常特征及找矿意义

本文介绍了嫩江县花朵山区水系沉积物异常和矿区土壤地球化学异常特征。通过对花朵山区区域地球化学特征进行分析,结合区内的成矿地质条件,认为Mo异常浓集中心明显,规模较大,与花岗闪长岩体关系密切。综合分析研究调查矿区地质、矿产、区域地球化学、土壤地球化学特征,结合区内自然地理和地球化学景观条件,全面评价区内矿产的资源潜力,为进一步地质找矿提供坚实的地球化学依据。     

内蒙古柴河地区二道河铅锌银矿外围隐伏矿体预测

二道河铅锌银矿床的成矿地质条件和产出的大地构造背景优越,其矿区及外围存在隐伏矿体的可能性较大。为深入研究矿区外围的找矿潜力,通过对二道河矿床地质、地球物理和地球化学特征的研究,结合区域成矿背景,利用地质简测、土壤地球化学测量和激电中梯测量相结合的综合信息找矿方法对矿区外围河口林场预测区进行了隐伏矿体预测。结果表明,河口林场预测区具有与二道河矿床相似的成矿地质条件,地球化学和地球物理异常套合程度高。通过靶区优选,区内共圈定出3 个重点找矿靶区和1 个次重点找矿靶区,推测其为铅锌银矿体赋存的最佳部位,为矿区及外围找矿提供依据。     

江西铁炉湾-吕阳斗成矿区找矿前景评价

铁炉湾-吕阳斗成矿区是江西九岭成矿带的重要组成部分。在对该区成矿地质条件综合分析和总结金（锑）成矿时空分布规律的基础上,对区内找矿前景和找矿方向进行了探讨,认为铁炉湾-吕阳斗成矿区有良好的金（锑）成矿地质条件,具备了寻找大-中型金（锑）矿床的资源潜力。     

综合物化探在浙西北某矿区多金属矿勘查中的应用

浙西北某矿区位于浙江省开化桐村—淳安梓桐重点勘查区内,是多金属成矿的有利区块,但以往物化探工作程度低,找矿一直未取得突破。文中以大铜坑矿段为例,利用地面高精度磁法、土壤地球化学测量和CSAMT等多种物化探方法,结合区内的成矿地质条件,对综合物化探异常作出了解释推断和综合评价。经钻探验证,物化探异常指明了找矿方向,取得了理想的地质效果,并对相邻矿段下一步地质找矿工作起到了指导作用。     

马关县坝堡锌银矿区地球化学特征及找矿前景

马关县坝堡锌银矿区属滇东南老君山Sn、Zn、Ag、W、Sb多金属地球化学分区之都龙-小锡板化学区。该矿区各单元地层的成矿元素丰度值较高,区内与热动力及花岗岩浆热液活动强烈,成矿地质条件越好。通过土壤地球化学测量,获得7个多元素组合异常,这些异常规模大、强度高。综合地质构造条件分析,其中2个异常可作为重点的找矿靶区。     

澳大利亚雅克比铅锌矿区土壤地球化学特征及找矿方向

历史上雅克比铅锌矿勘查区开展的地质勘查工作有限,可利用的资料较少,矿权区内的找矿工作未见大的突破。为 了对勘查区找矿潜力达到初步认识的目的,在区内开展了1:10000土壤地球化学测量工作。依据测量结果,从数理统计学的 角度,应用因子分析、相关分析和聚类分析的方法,研究矿区内成矿元素的组合;对土壤分析元素应用异常下限进行异常 圈定,发现元素异常的分布受地层组中发育的节理、裂隙等构造控制。德雷里安（Delamerian）造山期及以后的构造活动 可能为金属元素的活化、转移、富集、沉淀提供了储矿空间条件及热源条件,矿质可能来源于大陆风化产物及围岩。在结 合前期地质工作的基础上,在土壤地球化学测区内,提出三个找矿远景区,为下一步找矿工作提供依据。     

滇西北香格里拉市红牛—红山铜矿勘查系统模型

滇西北红牛—红山铜矿床是义敦—沙鲁里岛弧上与晚白垩纪中酸性侵入体有关的典型的斑岩-矽卡岩-热液型铜矿床。本文通过对其成矿地质背景、矿床地质特征、矿化富集规律及成矿模式、矿床地球物理和地球化学特征的综合研究，建立了红牛—红山铜矿床的"大比例尺地质填图和综合研究+重力+激电和高精度磁测+土壤化探测+工程验证"组合勘查技术方法、"燕山晚期石英二长斑岩+接触带矽卡岩和层间破碎带矽卡岩+重力低异常+高磁异常+高视极化率和低视电阻率异常+Cu-Mo-Pb-Zn-Ag-Au等元素综合异常"组合勘查模型。地质调查研究确定矿床成矿地质体和找矿地质体、矿化类型及其空间分布规律，建立矿床"四位一体"的成矿模式和区域-矿区地质找矿模型。区域中小比例尺的土壤化探测量确定区域找矿靶区，大比例尺土壤化探测量进一步缩小找矿靶区，逼近矿体赋存部位。矿区处于1∶5万土壤测量圈定的Cu-Pb-Zn-Mo-Au-Ag元素综合高异常区，1∶2.5万土壤测量圈出Cu-Pb-Zn-Ag-W元素综合异常面积较大、强度高、浓集中心明显、元素套合好，与矿区铜（铁）矿体赋存区域异常相对应。区域重力低异常区和正磁异常强度高区域是重要的找矿靶区，矿区大比例尺磁异常和激电异常区确定了矿体的空间位置和产状；矿区铜（铁）矿体赋存区为低视电阻率、高视极化率异常区，高精度磁测表现为正负磁异常相伴。矿区地质-地球化学-地球物理综合勘查模型对矿区深边部找矿起到重要的指导作用。     

广东陆河县塌山-江西坑地区锡多金属矿地质特征及找矿潜力

陆河县塌山-江西坑地区位于武夷成矿带粤东段,北东向莲花山深断裂带西束中段。区内动力变质作用控制了锡矿床点的分布,成矿元素Sn异常规模大、强度高、浓度分带及浓集中心明显。本文通过对塌山、江西坑及尖吉山三个典型矿区地质特征分析,讨论该区找矿潜力。     

黔东南金矿与圈定的黔湘桂新元古代火山构造特征及地质意义

黔东南金矿地质勘查及找矿研究程度低,为之利用区域重磁资料,研究深部成矿环境,圈定区内可能存在一处大型的中心式喷发火山环形构造或隐伏岩浆岩体分布群。岩体异常北东向分布,覆盖面积广,组合形态复杂,分带特征明显,跨越黔湘桂三省区,主体异常在贵州,部分在湖南和广西,并受控于3条深大断裂,见中心环带、内环带、过渡环带、外环带,4带发育齐全,火山岩相配套出现,岩体异常分枝发育。研究发现天柱—锦屏—黎平及丹寨—三都与湘西会同—怀化等地区金矿,极有规律地分布于相应构造环带和地表背斜区及有利赋矿地层内,由内环向外环依次出现石英脉型、蚀变岩型、微细粒浸染型金矿。所圈定的潜火山构造或隐伏岩体群,将对黔湘桂交界地区地质特征及金矿成矿规律产生新的认识,具有重要的地质意义。     

The variscan front and the midi fault between the channel and the meuse river

The ECORS seismic profile allows a new insight into the deep geology of northern France. Various geological data, such as ancient coal mines, surface mapping and boreholes, are used to interpret the seismic profile. A new cross-section, directly superimposed on the ECORS seismic profile (Cambrai-Dreux), is compared with a previous one, drawn along the Meuse River through the Ardenne Massif. The cylindrism and length-balancing hypotheses are discussed by comparing the two cross-sections. The main geological results are: (a) the emplacement of the Dinant Nappe is later than most of its internal deformation; and (b) major folding and thrusting give an approximate 30–35% shortening, without taking into account the internal deformation (minor folding and cleavage) and the unknown net translation vector of the Dinant Nappe (50 km at least, possibly 150 km).     

Geoelectrical Structure of the Crust and Upper Mantle in the Qinling and Adjacent Regions

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Gravity and magnetic surveys and interpretation in the northern part of the K-G basin

The gravity and magnetic data along three profiles across the northern part of the K-G basin have been collected and the data is interpreted for basement depths. The first profile is taken from Gadarada to Yanam covering a distance of 60 km and the second starts from Zangareddiguddem to Samathkur covering a distance of 110 km and the third is from Kotturu to Biyyapuppa covering a distance of 100 km. The gravity lows and highs have clearly indicated various sub-basins and ridges. The density logs from ONGC, Chennai, show that the density contrast decreases with depth in the sedimentary basin, and hence, the gravity profiles are interpreted using variable density contrast with depth. From the Bouguer gravity anomaly, the residual anomaly is constructed by graphical method correlating with well data, sub-surface geology and seismic information. The residual anomaly profiles are interpreted using polygon model. The maximum depths to the khondalitic basement are obtained as 5.61km, 6.46 km and 7.45 km for the first, second and third profiles respectively. The regional anomaly is interpreted as Moho rise towards coast. The aeromagnetic anomaly profiles are also interpreted for charnockite basement below the khondalitic group of rocks using prismatic models.     

四川盆地东北部长兴期沉积特征与沉积格局

四川盆地东北部长兴组（大隆组）为海洋环境的产物,根据沉积特点,可以分为碳酸盐台地沉积体系和盆地沉积体系。碳酸盐台地沉积体系又可进一步分为局限台地、开阔台地、台地边缘礁滩及缓坡等沉积相。在详细研究分析各沉积体系的沉积特点的基础上,探讨了该期沉积相带的空间分布,提出了不存在“开江一梁平”海槽的认识。笔者等认为在“开江梁平海槽”区域内,长兴组只是水体相对台地较深环境（台棚环境）的产物,为碳酸盐缓坡,不宜称为海槽。指出台地边缘浅滩及生物礁是储层最有利相带,礁白云岩及颗粒白云岩等是储层的有利微相。研究区的生物礁为碳酸盐台地边缘缓坡点礁群,沿着台地边缘断续分布。     

Comparison of the Canadian and US tornado detection and warning systems

Tornadoes are one of the most powerful and destructive weather events. The frequency of tornado occurrence is highest in North America, especially in the US Canada is second only to the US, and approximately, 80 occurrences are reported annually. Communities are impacted only when and if a tornado touches down on the ground. Early recognition of tornadoes and proper communication of warnings in the pre-touchdown phase helps the public to be ready and respond appropriately and effectively. Given that tornadoes are hard to predict and the warnings give only a very brief window of opportunity to prepare for evacuation to a secure underground or other location, each activity in the detection and warning phases is critically important. This study is focused on conducting a detailed comparison of the tornado detection and warning systems in the US and Canada. The sequences of activities and their interrelationships in the tornado detection and warning systems of each country are identified and developed as networks. A detection and warning network for Canada is developed, using Calgary as a case study, whereas a separate network is developed for the US, showing how local residents receive tornado warnings initiated by a local weather forecast office. Moreover, collaborating partners are identified, and their involvement at each level of the information flow is recognized. The two networks are compared and critically analyzed, focusing on the key issues, such as prediction/detection capabilities, warning decision-making, warning dissemination methods, and the spotters’ role. This qualitative comparison supports the recognition of key areas that need to be considered in improving the tornado detection and warning system in Canada.     

Time-dependent modeling of the Baltic entrance area. 1. Quantification of circulation and residence times in the Kattegat and the Straits of the Baltic sill

A prognostic model for the estuarine circulation in the Baltic entrance area is described. The model is based on the work by Stigebrandt (1983) and is built of a number of flow-regulating physical processes and forced by oceanic sea level, local meteorological conditions, and freshwater supply to the Baltic. It resolves the horizontal variations by dividing the entrance area into 7 sub-basins. The vertical stratification in each sub-basin evolves with time due to mixing, diffusion, and water exchange with adjacent basins. Instead of using a fixed vertical grid, the stratification is described by a variable number of layers created by inflowing water and by a pycnocline retreat near the surface. The model is a highly cost-effective tool compared to high-resolution 3D-models since computations are 10⁵–10⁶ times faster. Still, the model reproduces the stratification on time-scales longer than a few days as verified by comparison with observed time-series. The magnitude of the simulated average estuarine circulation conforms well to independent estimates of the water exchange. The model is used to quantify the temporal and horizontal variability of circulation, mixing, and diffusion. Long-term average rate of work against the buoyancy forces by entrainment and diffusion is calculated for each sub-basin. The highest rates of work against the buoyancy forces by diffusion are found in the northern Kattegat and in the Fehmarn Belt while the lowest rate is found in the Öresund. The total mixing in terms of transformation of water masses is also quantified. The average residence times for surface and deep water are estimated for each subbasin. Residence times longer than 1 mo are found in Fehmarn Belt and in the deep water of southern Kattegat. In other parts of Kattegat and the Samsø Belt the residence times are 1 to 2 wk for surface water and 2 to 3 wk for deep water. The age of the water is defined as the time spent since a particular water mass was in contact with either the sea surface or with the vertical model boundaries has been estimated. By comparing the age distribution in the Kattegat with observations of oxygen concentration, it is concluded that the variability of the ventilation of deeper layers is of less importance to the occurrence of low oxygen concentrations compared to other factors such as interannual variability in primary production.     

Structure and tectonic history of the Brisbane metamorphics in the Brisbane area

The Palaeozoic basement rocks of the Brisbane area have undergone three major deformations and a minor kinking episode. The central zone of Bunya Phyllite is dominated by a second‐generation transposition layering whereas the flanking Neranleigh‐Fernvale Beds are dominated by first‐generation transposition structures.

The major structure previously described in the area, the Indooroopilly Anticline, is an apparent antiform formed in part by the intersection of dominant first‐ and second‐generation structures and in part by a major third‐generation flxeure. The complete geometry of the first‐generation layering across the structure is suggested using vergence relationships but the stratigraphic relations and the structure of the stratigraphic boundaries are virtually impossible to deduce. Two possibilities are suggested and a major conclusion is that the Bunya Phyllite may be merely a unit within the Neranleigh‐Fernvale Beds.

The first‐generation deformation is a regional event whose effects can be traced north for some 500 km whereas the second‐ and third‐generation structures are more restricted. There is evidence to suggest that all three generations may be related to the same tectonic event, possibly Carboniferous in age.     

Paleozoic Stratigraphy in the Qiangtang Region of Tibet: Relations of the Gondwana and Yangtze Continents and Ocean Closure Near the End of the Carboniferous

Paleozoic sequences are defined for the northern and southern Qiangtang by linking field observations in the Gaize Province to the known Paleozoic record in neighboring areas. The pre-Devonian Gemuri Group of earlier authors is divided and the use of that term is no longer recommended. The upper Paleozoic rock assemblages, geological structures, and biota of the southern Qiangtang are of Gondwana glacial aspect, but those of the northern Qiangtang show more resemblance to those of the ancient Tethys. The two assemblages are interpreted as representing, respectively, the northern margin of Gondwanaland and the southwestern margin of the Yangtze continent. The two continents are suggested to have begun to separate during the Early Carboniferous and to have rejoined in the earliest Permian. Throughout this cycle of events, the northern Qiangtang occupied a passive margin while the southern Qiangtang rocks show evidence of the development of an active margin. Basaltic rocks from the southern Qiangtang are indicative of rifting. The authors consider that the boundary separating Car-boniferous and Permian rocks of Gondwanaland and Eurasia in the Qiangtang is marked by a suture zone that extends from Lungmuco through Heitonshan, Lake Gangma, Chasang, and Dongshuanghu. This suture is linked to Lancangjiang to the east and extends on to Malaya. In the Qiangtang the suture zone is marked by evidence of substantial rifting and by dismembered ophiolites.     

岩矿分析与经典法

回顾了近一个世纪以来经典的湿化学法（重量法和容量法）在岩矿分析方面的建立、发展情况。认为：经典法曾有过长期的持续发展，对地学研究有过巨大的贡献，但由于地学研究对象主要转移至痕量元素以及经典法不适合痕量分析，在一些以仪器分析为主要手段的实验室，有被取代的现象。指出：由于经典法依据的是全部原子、离子或分子参与的不可逆反应，是能够直接溯源至SI基本测量单位的分析技术，其优点为绝大多数仪器技术所不及，因此，它可以在某些领域被淡忘，但是不会消亡。