秦岭地区铅锌矿床模糊逻辑法找矿远景区优选

根据秦岭地区铅锌矿床成矿地质背景,应用ArcviewGIS对赋矿地层、控矿构造等进行空间分析,提取预测变量。依据不同预测变量与铅锌矿床的相关性大小,选择不同的模糊算子进行综合,生成识别控矿因子。参考伽马算子、综合控矿因子,进行成矿远景区划分,并依据伽玛算子大小进行靶区优选。     

模糊逻辑法在云南中甸地区铜矿潜力预测中的应用

模糊逻辑建模应用于矿产预测时分为两步:①变量模糊化,应用隶属函数计算变量的模糊隶属度;②模糊综合,应用模糊算子(模糊与、模糊或、模糊代数和、模糊代数积和伽马算子)对模糊化后的变量进行综合,生成最终的模糊有利度图.在介绍了模糊逻辑的基本原理和详细分析云南中甸铜成矿规律的基础上,应用ArcView GIS及其扩展模块ArcSDM对研究区地质、地球化学、线性构造等方面的数据进行了处理,提取了预测变量.模型应用于云南中甸普朗地区斑岩铜矿的区域成矿预测(1:20万)结果显示,预测出的成矿潜力区包含了81%以上的已知矿点,可以用于指导进一步的大比例勘查工作.     

基于GIS的证据权模型在秦岭～松潘金矿潜力预测中的应用

数据驱动的证据权法被用来进行金矿潜力制作。为了确定秦岭~松潘金矿的潜力区,需利用地质、地球化学、地球物理等数据。数据采集、图形处理、空间分析都是在GIS平台上进行的。预测结果表明,证据权法在综合不同空间数据上是有效的,最终的预测图件圈出了最有利的矿化区,可用于进一步勘查研究。     

秦岭大陆碰撞金成矿机制与金矿带时空定位

通过分析秦岭巨型金矿带内353处岩金矿床的时空分布特征发现,带内矿化强弱变化有序,由NE向SW依次分出小秦岭-熊耳山强矿化带、北秦岭弱矿化带、中秦岭强矿化带、南秦岭弱矿化带和松潘-甘孜强矿化带5个亚带。它们的成矿时代始于印支期,经燕山期,终于喜马拉雅早期。其中小秦岭-熊耳山亚带主成矿期为燕山晚期,中秦岭亚带主成矿期为燕山早期,松潘-甘孜亚带主成矿期为燕山晚期至喜马拉雅早期。金矿带时空定位在于控矿构造带的时空定位。空间上,控矿构造带包容金矿带或基本一致;时间上,金矿带与控矿构造带基本同步或滞后。金矿带时空变化原因在于控矿构造带的构造迁移,从控矿构造带的主断面向两侧迁移,迁移速率0．78～3．5km／Ma。金矿带及其控矿构造带的形成和迁移原因在于大陆碰撞。大陆碰撞及其俯冲带下插构造位的加深,依次形成变质岩及变质成矿热液-改造系列花岗岩及气液成矿流体-同熔系列花岗岩及超临界成矿流体。不同构造位的成矿流体特征不同,形成不同矿床成因类型。成矿流体上升形式和构造空间不同,形成不同的矿化类型。     

基于模糊逻辑法的冀西北地区铅锌银多金属矿定位预测

模糊逻辑空间决策模型在变量取值上不是采用二态法将研究区分为成矿有利区和成矿不利区两部分,而是根据地质数据的规律取连续变化的隶属度赋值,有效避免了有用地质信息的丢失。笔者在GIS平台上利用Arc-SDM模块对冀西北地区的地质、地球化学、地球物理等资料进行了处理,利用证据权法进行了线缓冲形成的证据层与矿床（点）之间的亲近度分析,在此基础上采用列表法对原始地质变量进行了直观模糊隶属度赋值。模糊逻辑的预测结果表明,在圈出的仅占研究区面积13.2%的靶区范围内有85%的已知矿床（点）出现,与已知矿床（点）吻合程度高,预测效果理想,其结果可用于指导下一步找矿工作。     

甘肃早子沟金矿三维建模与综合成矿预测

甘肃早子沟金矿是西秦岭成矿带上矿床规模较大,研究程度较高的构造蚀变岩性金矿典型代表。针对早子沟金矿床深部找矿方向与成矿潜力,本文采用三维地质建模手段,成矿有利信息提取方法,开展基于找矿地质模型的三维建模与综合成矿预测。研究结果表明:甘肃早子沟金矿适用于控矿断裂+有利岩体+有利围岩蚀变+等间距控矿的综合地质找矿模型;地质异常变量定量分析与提取结果在地质认识上均得到较好的印证,综合成矿预测结果显示矿床明显受多期次构造控制矿化叠加富集,Au1、Au9、Au30、M16等主矿体深部具有良好的找矿潜力。     

基于模糊逻辑T算子和协T算子的地下水水质评价

本文运用地下水水质的模糊综合评判分析方法，选取地下水水质的主要影响因子，借助模糊逻辑T算子和协T算子，编制了有效的MATLAB计算机程序，绘制了隶属度函数的数学图形，对北方某水源地地下水水化学资料进行了模糊数学综合评价。评价结果表明，研究区采样点水质为Ⅰ、Ⅱ、Ⅲ级的占96．63％，大部分地下水水质较好，符合饮用水的要求。借助T和协T逻辑算子的模糊综合评判法评价地下水水质效果较好。     

南秦岭迭部地区碳硅泥岩型铀矿资源定量预测评价

通过对南秦岭迭部地区碳硅泥岩型铀矿成矿地质条件和成矿地质特征的研究,确定了铀矿床的关键控矿因素和成矿远景预测要素。在此基础上,利用MapGis软件对各要素进行了空间定位,并系统编制了成矿要素图和预测要素图;应用MRAS软件对预测要素进行配置,选取其最佳的预测要素组合,构置预测变量,并计算变量与铀成矿的相关性、最小单元成矿有利度,利用人机联合圈定、优选出最小靶区。最后,采用修正体积法和德尔菲法对资源进行定量和半定量估算,并对靶区进行可信度评价和分级。     

西秦岭阳山金矿带控矿因素、找矿标志及深部成矿预测

目前对西秦岭阳山金矿带勘查评价正在加速进行,为了进一步查明该矿带成矿规律和找矿潜力,指导矿田深部勘查找矿工作,武警黄金第十二支队在矿区开展了深部矿产调查和研究。文章在前人研究的基础上,通过最新的地质、地球物理勘查和室内综合研究,分析和总结了阳山金矿带主要控矿因素和找矿标志以及各因素的控矿机制。研究显示:区内的北东东向、近东西向断裂系统多沿葛条湾-草坪梁复背斜南翼层间褶皱岩层薄弱面或不同岩性接触面发育,在成矿过程中起到通道作用,限定了矿体的展布,为主要控矿因素。在明确找矿标志的基础上,以安坝矿段为研究对象,采用三维地质建模找矿信息量法进行了定量成矿预测,共圈定出深部找矿靶区4处,为矿区下一步的勘查指明了方向。     

找出主要控矿因素,建立三因控矿分析

通过几个已知金矿区的研究,认识到不同矿区有不同的控矿因素。首先找出最主要的控矿因素,再配合两个深层相关因素,进行矿体定位。本文简述三因控矿分析方法在不同类型金矿成矿预测中的应用。     

应用模糊集合论圈定找金靶区

本文依据岩浆岩常量评价因子的系统分析和建立在模糊集合论基础上的矿化隶属度研究,得到了能识别包括金在内的10种多金属矿(Au、Cu、Mo、U、W、REE、Nb-Ta、Be和Sn)的母岩的方法。以江苏省岩浆岩为例,计算了有关岩体的金矿化隶属度,划分了4级找金靶区,对指导找矿起到了积极作用。作者用该法对一些著名产金矿岩浆岩的化学成分所作的研究表明,所设计的两类与金矿化隶属度有关的数学模型及其聚类中心是合理的、准确的。     

A fuzzy set based approach for integration of thematic maps for landslide susceptibility zonation

Spatial prediction of landslides is termed landslide susceptibility zonation (LSZ). In this study, an objective weighting approach based on fuzzy concepts is used for LSZ in a part of the Darjeeling Himalayas. Relevant thematic layers pertaining to landslide causative factors have been generated using remote sensing and geographic information system (GIS) techniques. The membership values for each category of thematic layers have been determined using the cosine amplitude fuzzy similarity method and are used as ratings. The integration of these ratings led to the generation of LSZ map. The integration of different ratings to generate an LSZ map has been performed using a fuzzy gamma operator apart from the arithmetic overlay approach. The process is based on determination of combined rating known as the landslide susceptibility index (LSI) for all the pixels using the fuzzy gamma operator and classification using the success rate curve method to prepare the LSZ map. The results indicate that as the gamma value increases, the accuracy of the LSZ map also increases. It is observed that the LSZ map produced by the fuzzy algebraic sum has reflected a more real situation in terms of landslides in the study area.     

Exploration feature selection applied to hybrid data integration modeling: Targeting copper-gold potential in central Iran

A Sugeno-type fuzzy inference system is implemented in the framework of an adaptive neural network to map Cu–Au prospectivity of the Urumieh–Dokhtar magmatic arc (UDMA) in central Iran. We use the hybrid “Adaptive Neuro Fuzzy Inference System” (ANFIS; Jang, 1993) algorithm to optimize the fuzzy membership values of input predictor maps and the parameters of the output consequent functions using the spatial distribution of known mineral deposits. Generic genetic models of porphyry copper–gold and iron oxide copper–gold (IOCG) deposits are used in conjunction with deposit models of the Dalli porphyry copper–gold deposit, Aftabru IOCG prospect and other less important Cu–Au deposits within the study area to identify recognition criteria for exploration targeting of Cu–Au deposits. The recognition criteria are represented in the form of GIS predictor layers (spatial proxies) by processing available exploration data sets, which include geology, stream sediment geochemistry, airborne magnetics and multi-spectral remote sensing data. An ANFIS is trained using 30% of the 61 known Cu–Au deposits, prospects and occurrences in the area. In a parallel analysis, an exclusively expert-knowledge-driven fuzzy model was implemented using the same input predictor maps. Although the neuro-fuzzy analysis maps the high potential areas slightly better than the fuzzy model, the well-known mineralized areas and several unknown potential areas are mapped by both models. In the fuzzy analysis, the moderate and high favorable areas cover about 16% of the study area, which predict 77% of the known copper–gold occurrences. By comparison, in the neuro-fuzzy approach the moderate and high favorable areas cover about 17% of the study area, which predict 82% of the copper–gold occurrences.     

Geology,geodynamics and orogenic gold prospectivity modelling of the Paleoproterozoic Kumasi Basin,Ghana, West Africa

This paper describes the geology and tectonics of the Paleoproterozoic Kumasi Basin, Ghana, West Africa, as applied to predictive mapping of prospectivity for orogenic gold mineral systems within the basin. The main objective of the study was to identify the most prospective ground for orogenic gold deposits within the Paleoproterozoic Kumasi Basin. A knowledge-driven, two-stage fuzzy inference system (FIS) was used for prospectivity modelling. The spatial proxies that served as input to the FIS were derived based on a conceptual model of gold mineral systems in the Kumasi Basin. As a first step, key components of the mineral system were predictively modelled using a Mamdani-type FIS. The second step involved combining the individual FIS outputs using a conjunction (product) operator to produce a continuous-scale prospectivity map. Using a cumulative area fuzzy favourability (CAFF) curve approach, this map was reclassified into a ternary prospectivity map divided into high-prospectivity, moderate-prospectivity and low-prospectivity areas, respectively. The spatial distribution of the known gold deposits within the study area relative to that of the prospective and non-prospective areas served as a means for evaluating the capture efficiency of our model. Approximately 99% of the known gold deposits and occurrences fall within high- and moderate-prospectivity areas that occupy 31% of the total study area. The high- and moderate-prospectivity areas illustrated by the prospectivity map are elongate features that are spatially coincident with areas of structural complexity along and reactivation during D4 of NE–SW-striking D2 thrust faults and subsidiary structures, implying a strong structural control on gold mineralization in the Kumasi Basin. In conclusion, our FIS approach to mapping gold prospectivity, which was based entirely on the conceptual reasoning of expert geologists and ignored the spatial distribution of known gold deposits for prospectivity estimation, effectively captured the main mineralized trends. As such, this study also demonstrates the effectiveness of FIS in capturing the linguistic reasoning of expert knowledge by exploration geologists. In spite of using a large number of variables, the curse of dimensionality was precluded because no training data are required for parameter estimation.     

基于模糊逻辑的中甸岛弧斑岩型铜矿定位预测

文章选择中甸岛弧地区中比例尺地表填图所圈定的侵入岩及火山岩、航磁解译构造格架及汇水盆地沉积物多元素异常作为斑岩型铜矿定位预测的主要方法,总结提出了该区斑岩型铜矿的定位预测准则,并根据该准则在GIS平台上基于模糊逻辑模型进行了模糊成员权重赋值和模糊推理网络构建。通过模糊推理计算得到该区不同高度、不同方向航磁解译构造的交汇部位以及不同元素的组合异常特征,最终确定了该区可以发现斑岩型铜矿的模糊概率分布图。该区主要矿床如普朗、红山和雪鸡坪等均处于高模糊概率分布区,经野外检查验证发现普上和地苏嘎两处斑岩铜矿矿化新区。     

Using fuzzy logic in a Geographic Information System environment to enhance conceptually based prospectivity analysis of Mississippi Valley‐type mineralisation

Geographic Information Systems (GIS) provide an efficient vehicle for the generation of mineral prospectivity maps, which are products of the integration of large geological, geophysical and geochemical datasets that typify modern global‐scale mineral exploration. Conventionally, two contrasting approaches have been adopted, an empirical approach where there are numerous deposits of the type being sought in the analysed mature terrain, or a conceptual approach where there are insufficient known deposits for a statistically valid analysis. There are also a variety of potential methodologies for treatment of the data and their integration into a final prospectivity map. The Lennard Shelf represents the major Mississippi Valley‐type (MVT) province in Australia; however, there are only 13 deposits or major prospects known, making an empirical approach to prospectivity mapping impractical. Instead, a conceptual approach was adopted, where critical features that control the location of MVT deposits on the Lennard Shelf, as defined by widely accepted genetic models, were translated into features related to fluid pathways, depositional traps and fluid outflow zones, which can be mapped in a GIS and categorised as either regional or restricted diagnostic, or permissive criteria. All criteria were derived either directly from geological and structural data, or indirectly from geophysical and geochemical datasets. A fuzzy‐logic approach was adopted for the prospectivity analysis, where each interpreted critical feature of the conceptual model was assigned a weighting between 0 and 1 based on its inferred relative importance and reliability. The fuzzy‐logic method is able to cope with incomplete data, a common problem in regional‐scale exploration datasets. The data were best combined using the gamma operator to produce a fuzzy‐logic map for the prospectivity of MVT deposits on the southeastern Lennard Shelf. Five categories of prospectivity were defined. Importantly, from an exploration viewpoint, the two lowest prospectivity categories occupy ～90% and the highest two categories only 1.6% of the analysed area, yet eight of the 13 known MVT deposits lie in the latter and none in the former: i.e. all lie within ～10% of the area, despite the fact that deposit locations were not used directly in the analysis. The propectivity map also defines potentially mineralised areas in the central southeastern Lennard Shelf and the southern part of the Oscar Ranges, where there are currently no known deposits. Overall, the analysis demonstrates the power of fuzzy‐logic prospectivity mapping on a semi‐regional to regional scale, and emphasises the value of geological data, particularly accurate geological maps, in exploration for hydrothermal mineral deposits that formed late in the evolution of the terrain under exploration.     

成矿环境空间结构的模糊建模

为了提高矿产预测的精度和可靠性, 必须分析和利用与矿床有关的空间结构信息.提出了一种用模糊集建立成矿环境空间结构模型的方法.成矿环境空间结构是地质变量在矿床周围的分布, 可用变量与空间点之间的模糊关系来描述.同一地区的同类矿床, 其空间结构具有一定相似性, 通过这种相似性的极大化可对结构模型进行优化.优化的结构模型是一种包含了方向和距离关系的特殊的空间关联规则集, 也是模糊推理矿产预测的推理规则库.通过模糊推理进行结构相似性的比较, 可对任意点上的找矿有利性进行预测.以云南东川地区铜矿预测的实例说明了该方法具有良好的应用效果.      

贵州水银洞金矿矿层矿化分析与深部预测

水银洞金矿为滇黔桂"金三角"最重要的金矿床,是典型的卡林型层控金矿床。运用绘制等高线图和含矿层矿化分布图的方法,对水银洞矿床0~427勘探线的钻孔数据分析,并用surfer软件绘制矿层的顶底板和地层矿化趋势的模拟图,重点分析了含矿地层的构造形态和矿化规律,结果显示:界面等高线反应背斜的形态,水银洞矿区背斜的高点和背斜倾伏端是金矿的主要赋存位置;Sbt(构造蚀变体)与上部龙潭组矿化值有负相关效应;水银洞矿化整体具有不均匀性,Sbt向东南延伸且在东西向具有弱—强—弱的富集规律。Sbt矿化强度在东西向具有弱—强—弱的规律,而龙潭组地层中的矿化与Sbt呈现一定负相关效应,在背斜倾伏端龙潭组矿化度开始增强,预示深部地层可能还会有大规模的工业矿体存在。     

基于模糊证据权法的广西典型金矿矿产定量预测

多信息融合的矿产资源定量预测是当前资源潜力预测的前缘课题,不同地质背景信息与地球化学数据的深度挖掘是当前该领域急需解决的关键问题。文章通过总结广西各构造单元地质背景和成矿控制要素,在ArcGIS、GeoDAS等软件平台基础上,分析了广西全区60767个地球化学样品中Au、Ag、Mn、Cu、Pb、Zn、Sn、Sb等主要成矿及伴生元素的空间分布特征。基于GeoDAS平台,通过IDW插值、S-A异常分解、主成分分析等技术,选取地球化学组合元素异常、重磁异常以及岩浆岩与断层交点缓冲区数据,通过模糊证据权模型,重点选取卡林型金矿和破碎带蚀变金矿2种典型矿产类型,编制了成矿后验概率图,圈定了金成矿有利地段。该研究对应用新的成矿理论和评价技术方法在广西开展矿产资源潜力评价以及区划工作具有重要的参考意义。