Geochemical characteristics and spectrometric prospecting in the muscovite-bearing pegmatites and granites, southeastern Aswan, Egypt

Rare metal mineralization of Sn, Nb-Ta and W is encountered in the Gebel Dihmit area (GDA), south- eastern Aswan, Egypt. The mineralization is related to muscovite granites and their pegmatite derivatives. The peg- matites are divided into three types according to their main mineral assemblages: K-feldspar-muscovite-tourmaline, K-feldspar-albite-muscovite and albite-K-feldspar-lepidolite veins. Petrogenetic studies indicate that Sn and Nb-Ta mineralization extends from the late-magmatic stage to the pegmatite and hydrothermal stages of the (GDA) suite. The albite-K-feldspar-lepidolite granite is composed dominantly of albite, lepidolote, and quartz, with topaz, K-feldspar and amblygonite. The accessory minerals are zircon, monazite, pollucite, columbite-tantalite, microlite and Ta-rich cassiterite. Phenocrysts of quartz, topaz and K-feldspar contain abundant inclusions of albite laths and occasional lepidolite crystals along growth zones (snowball texture), indicating simultaneous crystallization from a subsolvus, residual magma. The origin of the pegmatites is attributed to extreme differentiation by fractional crystal- lization of a granitic magma. The economic potential for rare metals was evaluated in the geochemical discrimination diagrams. Accordingly, some of the pegmatites are not only highly differentiated in terms of alkalis, but also the promising targets for small-scale Ta and, to a less extent, Sn. The pegmatites also provide the first example of Fe-Mn and Nb-Ta fractionation in successive generations of granites to cassiterite-bearing pegmatites, which perfectly ex- hibit similar fractionation trends established for primary columbite-tantalite in the corresponding categories of peg- matites. Uranium and Th of magmatic origin are indicated by the presence of thorite and allanite, whereas evidence of hydrothermal mineralization is the alteration of rock- foring minerals such as feldspar and the formation of sec- ondary minerals such as uranophane..

Geochemical Characteristics and Prospecting Direction of the Hongwei-Xiongguan-Songheyi Dongshan Area in the Greater Xing’an Mountains, Heilongjiang Province

The Daxinganling area collided during the Late Paleozoic.The study area Hongwei-Xiongguan-Songheyi Dongshan area is located at the superimposed transition site of the Paleozoic paleo-Asian tectonic-metallogenic domain and the Mesozoic-Cenozoic Pacific Ocean tectonic-mineralization area.It is a good ore-forming fluid channel and has very good ore metallogenic geological conditions.The comprehensive research and metallogenic prediction of the geological background and geochemical characteristics of this area are carried out.It is believed that this area has good prospecting potential,and the prospecting area is circled.Suggestions for further prospecting work in this area are put forward.

Geochemical Anomalies Identified by Multifractal Modeling: Implications for Mineral Exploration in the Ziyoutun Cu-Au District, Jilin Province, China

The Ziyoutun Cu-Au district is located in the Jizhong–Yanbian Metallogenic Belt and possesses excellent prospects. However, the thick regolith and complex tectonic settings present challenges in terms of detecting and decomposition of weak geochemical anomalies. To address this challenge, we initially conducted a comprehensive analysis of 1:10,000-scale soil geochemical data. This analysis included multivariate statistical techniques, such as correlation analysis, R-mode cluster analysis, Q–Q plots and factor analysis. Subsequently, we decomposed the geochemical anomalies, identifying weak anomalies using spectrum-area modeling and local singularity analysis. The results indicate that the assemblage of Au-Cu-Bi-As-Sb represents the mineralization at Ziyoutun. In comparison to conventional methods, spectrumarea modeling and local singularity analysis outperform in terms of identification of anomalies. Ultimately, we considered four specific target areas(AP01, AP02, AP03 and AP04) for future exploration, based on geochemical anomalies and favorable geological factors. Within AP01 and AP02, the geochemical anomalies suggest potential mineralization at depth, whereas in AP03 and AP04 the surface anomalies require additional geological investigation. Consequently, we recommend conducting drilling, following more extensive surface fieldwork, at the first two targets and verifying surface anomalies in the last two targets. We anticipate these findings will significantly enhance future exploration in Ziyoutun.

Prospectivity modeling of porphyry copper deposits: recognition of efficient mono-and multi-element geochemical signatures in the Varzaghan district, NW Iran

The Varzaghan district at the northwestern margin of the Urumieh–Dokhtar magmatic arc, is considered a promising area for the exploration of porphyry Cu deposits in Iran. In this study we identified mono-and multi-element geochemical anomalies associated with Cu–Au–Mo–Bi mineralization in the central parts of the Varzaghan district by applying the concentration–area fractal method. After mono-element geochemical investigations, principal component analysis was applied to ten selected elements in order to acquire a multi-element geochemical signature based on the mineralization-related component. Quantitative comparisons of the obtained fractal-based populations were carried out in accordance with known Cu occurrences using Student's t-values. Then,significant mono-and multi-element geochemical layers were separately combined with related geologic and structural layers to generate prospectivity models, using the fuzzy GAMMA approach. For quantitative evaluation of the effectiveness of different geochemical signatures in final prospectivity models, a prediction-area plot was adapted. The results show that the multi-element geochemical signature of principal component one(PC1) is more effective than mono-element layers in delimiting exploration targets related to porphyry Cu deposits.

Geofluids Hosted in the Deep Crust: From Systematics to Parametrization of their Significance

Earthquake is a sudden release of energy due to fault motions.The severity of the damages can be minimized by development of a culture of prevention which includes the Seismic Hazard Assessment,microzonation studies and appropriate building codes.

A Critical Analysis of Gold Prospecting Methods

Exploration and prospecting for mineral resources deposits are perceived to not be an easy process due to big deposits being discovered in early times. Numerous gold prospecting methods have been used in gold prospecting. The aim of this research is to critically analyze both traditional and modern gold prospecting methods that are being used in gold exploration. The research objective is to critically evaluate the numerous studies that focus on gold prospecting methods in an effort to provide an effective analysis of gold prospecting methods. In doing so, the study has used a qualitative method to review the existing literature. The study reviews academic journals and articles, books, and periodicals which were published between 2010 and 2019. This study has achieved to critically analyze both traditional and modern gold prospecting methods. The study finds out that the traditional gold prospecting methods include gold panning and dry washing. Additionally, the current gold prospecting methods include biological prospecting, geochemical prospecting and geophysical prospecting methods.

Geochemical Prospection of the Chapala Ciénega at Michoacán State

The geochemical prospection as a branch of Applied Geochemistry or “Geochemistry of the Landscape” studies the spatial and temporal location of geochemical anomalies in order to locate geological resources of economic value. The Ciénega de Chapala zone in Michoacán is located east of the Citala rift hosting a geological system that leads to regional hydrothermal activity, mainly the Pajacuaran and Ixtlan failures. The regional geothermics include a superficial hydrothermalism consisting of springs and wells of hot water with temperatures between 48°C and 94°C in Ixtlan de los Hervores and mud volcanoes in the water with temperatures between 48°C and 94°C in Ixtlan de los Hervores and mud volcanoes in the Los Negritos. The waters and gases of these hydrothermal manifestations have physicochemical characteristics that indicate the presence of geothermal fluids. To search for possible presence of minerals of economic value, a study of elemental chemical analysis was performed by scanning electron microscopy in samples of rock of the sierra de Pajacuaran, the result of the analysis is clearly abnormal values which may be indicative a geochemical anomaly as well as the possible presence of minerals of economic value in the region. Given the above, the area of the Ciénega de Chapala in Michoacán is a zone where work can be continued both geothermal and mineralogical exploration by conventional techniques or even totally innovative technologies.

西北地区主要锂矿资源分布特征及地球化学找矿远景预测

为圈定锂成矿远景区,采用已有1∶20万地球化学数据,选取西昆仑-阿尔金和阿尔泰两个主要锂矿带,基于锂元素地球化学空间分布及异常特征圈定锂矿远景区,为找矿突破战略行动选区服务。基于重点锂矿带以往1∶20万地球化学数据库,对元素相关性、背景及异常特征等参数进行再分析,结合已有锂矿床或锂矿(化)点,圈定找矿远景区。在昆仑-阿尔金地区圈定锂地球化学异常区15处,在阿尔泰圈定锂地球化学异常区12处。研究圈定27处异常区可为下一步锂矿找矿工作部署提供参考依据。

坦桑尼亚恩泽加地区覆盖区选区评价及综合找矿方法研究

恩泽加(Nzega)绿岩带为坦桑尼亚环维多利亚湖八大绿岩带之一,为坦桑尼亚重要的产金区域之一。由于其地表覆盖程度较高,地质调查和勘查工作程度较低,虽然针对隐伏型金矿床尚具备一定的找矿潜力,但同时也面临选区评价和找矿困难的问题。研究表明:在选区评价中,针对太古界尼安萨群条带状铁建造的区域航磁异常解译和研究区地球化学金异常分析是最主要的;而在采用地物化综合找矿方法开展勘查工作中,磁法和激电法结合对于寻找覆盖区下的含铁建造内部或接触带附近或剪切带内的金矿床效果较好。该地区首次使用了取样钻施工采样,对覆盖层下发育的含金矿化蚀变带进行了地质工程揭露,取得了一定的找矿成果,先后发现了伊博罗格罗(Iborogo)、卢素(Lusu)和乔马(Choma)等多个金矿床(点)。

甘肃北山红柳园—辉铜山地区成矿地质条件、地球化学特征及找矿新发现

甘肃北山红柳园—辉铜山地区位于甘肃北山南带,是形成铜、镍、铁、铅锌、钼、金、银等矿床的有利地区,具有较好的找矿潜力。通过开展成矿地质条件分析,总结控矿关键因素,依据水系沉积物地球化学特征,确定Au、Ag、As、Sb、Hg、W、Sn、Ni、Cu为区内主要的成矿(伴生)元素。Ni、Cu异常与基性-超基性侵入岩的分布有关,Au异常受华力西中期似斑状花岗岩及加里东晚期石英闪长岩控制明显,与区域性断裂及其旁侧平行或“入”字斜交的次级断裂关系密切。异常查证新发现铭扬铜镍矿、杨帆金矿等多处矿点及矿化线索,结合区域地质、物探、化探特征,优选出4处具较大成矿潜力的找矿远景区,尤其是早古生代铭杨铜镍矿的发现,实现了北山地区近年来铜镍矿找矿新突破。研究成果可为下一步找矿勘查部署提供重要依据。

西非科特迪瓦某区土壤地球化学特征及找矿前景分析

研究区位于西非克拉通南部的古元古代鲍勒—莫西域(Baoulé-Mossi Domain)内,该区为西非最重要的金成矿区。本文通过对研究区内土壤Au、Ag、As、Cu、Pb、Co、Cr七种元素的含量、浓集比率、变异系数等地球化学参数的系统统计分析,得出该区Au元素具有浓集比率大,变异系数高的特征,为该区主要的成矿元素,As元素具有较高的浓集比率和变异系数,且异常范围与Au元素异常范围部分重合,为Au元素的指示元素,本次测量面积为5 km~2,采样网度800 m×200 m,共采集样品594件。并在研究区土壤地球化学测量异常、地质特征及区域成矿地质背景的基础上,圈定了Au-Ⅰ、Au-Ⅱ、Au-Ⅲ、Au-Ⅳ、Au-Ⅴ、Au-Ⅵ共6处金矿找矿靶区,经钻探工程验证,在Au-Ⅰ靶区发现了隐伏金矿体。综合对比研究区内圈定的找矿靶区的地质条件与区域内已发现金矿床的成矿地质条件,推测研究区内圈定的金矿找矿靶区有巨大的找矿潜力。

气体地球化学勘查在巴—麦地区砂岩型铀矿找矿中的应用

塔里木盆地内部砂岩型铀矿找矿十分迫切。针对该盆地地质构造相对复杂、沉积地层厚度大、勘查手段受到沙漠-荒漠地貌的限制、勘查程度较低和地表成矿信息弱的特点,在巴楚隆起—麦盖提斜坡带地区(巴—麦地区)开展能指示深部地层环境的H_(2)S、CH_(4)、H_(2)、CO_(2)和4He气体地球化学区域测量研究。结果表明,几种土壤气体浓度能够较为清晰地显示各自异常分布范围,并指示盆地地层中可能的铀异常信息,气体地球化学测量方法是一种相对高效的盆地区域地表勘查方法。在综合测区断裂分布、油气藏、水文等地质条件和气体化学反应性质的基础上,分析气体浓度异常成因及分布综合特征,测区东北部、东南部及色力布亚断裂和巴什托断裂所夹持部分地段具有几种气体组份浓度异常叠加,地层中可能发育氧化-还原地球化学障,是有利的找矿预测区,为该地区砂岩型铀矿勘查提供参考依据。

云南金平地区Au、Cu、Pb、Zn、Ag成矿元素时空分布特征及找矿预测

云南金平地区是哀牢山南段重要的Au、Cu多金属矿集区,而Au、Cu为该区主成矿元素的论断和依据缺乏,Au、Cu等成矿元素时空富集配分规律、约束机制尚无论断,该区找矿方向及靶区需进一步明确。本文通过开展1∶5万金平县幅水系沉积物测量工作,统计分析全区及各主要地质单元元素含量平均值(X)和相对富集系数(K)等,结合金平地区的地球化学参数特征和元素间组合关系、元素异常与成矿相关性,确定了Au、Cu、Pb、Zn、Ag为金平地区主成矿元素。通过分析元素地球化学时空分布富集规律,可知金平地区元素地球化学富集配分受时间、空间限制,该地区Au、Cu、Pb、Zn、Ag主成矿元素富集峰期为两个阶段(300~400 Ma、470~485 Ma),进而确定了奥陶系、志留系、泥盆系、石炭系、二叠系为该地区最具找矿潜力的时代及地层。通过系统研究元素异常与构造、岩浆和成矿的关系,发现区内三家河断裂、马过河断裂、甜竹山断裂对元素富集有明显的影响和控制作用,金平地区元素异常与成矿具有密切相关性。结合金平地区成矿规律和控矿因素等,圈定了12处综合异常,划定了2个找矿预测区,对2个找矿预测区进行找矿潜力分析,指明了找矿方向,提出了进一步工作建议。

辽宁新房金矿床原生晕地球化学特征及对深部找矿的指示

辽东半岛南部的新房金矿床由22、23、24、25、27号5条矿脉带组成,矿区内主要矿体已被发现,提能增储成为制约矿山持续服务的因素,矿床勘查过程中的钻探工程部署迫切需要科学、有效的成矿预测依据。以新房金矿床106线14个钻孔原生晕数据为研究对象,研究地球化学特征和元素分带规律,建立轴向分带序列,在研究原生晕地球化学特征基础上开展深部找矿预测。结果表明,新房金矿的前缘晕元素为As、Sb、Hg,近矿晕元素为Au、Ag、Cu、Pb、Zn,尾晕元素为W、Mo、Bi。采用分带指数法计算了22、23、24、25、27号5条矿脉带的轴向分带序列,指示5条矿脉带均出现“反分带”现象,可能是不同矿化阶段的矿体在空间上叠加导致正常的轴向分带序列出现错位。22、23、24、27号矿脉带的中下部出现较强的前缘晕和近矿晕,结合地球化学参数特征,这4条矿脉带的As/W、As/Mo、Sb/W、(As×Sb)/(Mo×W)评价指标出现多次振荡波动,并且在深部由降转升,指示深部有较好的找矿潜力。综合以上分析认为,新房金矿床经历多次成矿热液活动,在106勘探线东侧矿体还有一定的延伸。

江苏新沂高流地区土壤地球化学特征及找矿预测

在总结江苏新沂高流地区地质特征的基础上,结合区内1∶10000土壤地球化学调查工作,系统研究该区元素含量及组合特征,并进行找矿预测。异常结果显示该区Au、Ag、Cu、Mo、Pb、Zn、As、Sn等单元素地球化学异常明显,其中Au、Ag、Mo 3个元素的异常强度和分带性均好,其形态分布受NNE向构造破碎和碱长花岗岩体等因素制约。在研究区共圈定了14处综合异常,通过异常评价,位于同一断裂带附近的3处异常成矿地质条件优越;对综合异常开展地球化学剖面查证工作,结果显示其中1处Au、Cu等元素峰值均位于NNE向断裂带中心位置。结合该区成矿地质条件和土壤地球化学异常特征,初步总结了研究区金、多金属矿找矿标志,为该区进一步找矿提供间接依据。

重液分选茶卡北山水系沉积物及其对伟晶岩型锂矿床探矿的指示意义

伟晶岩型锂矿是最重要的锂金属来源之一,由于在时间、空间和构造背景方面存在显著的不均一性,该型矿床目前尚无有效的探矿方法。在迁移搬运过程中,水系沉积物保留了蚀源区矿物信息,利用其元素和矿物组成,可在一定程度上还原沉积物物源区的矿物组成特征。分析水系沉积物中含锂重矿物的亏损与富集以及粒径的变化,是伟晶岩型锂矿探矿的有效方法之一。文章以茶卡北山流域的水系沉积物为研究对象,经逐级精细化地重液分选,实现了重、轻质矿物的有效分选。结果表明,河流过程可以对水系沉积物中的锂含量产生较大的影响,无支流时的搬运距离越远,水系沉积物中的锂含量越少,支流混合可以对水系沉积物中的锂含量产生正相关影响。重液分选方法对水系沉积物含锂矿物产生了有效的富集作用,主要富集锂元素的载体为云母类矿物,锂元素含量较未分选前提高3~14倍,且在分选后产生了明显的矿物组成差异。这种变化规律可用于对含锂伟晶岩矿物的指示与追踪,因此水系沉积物的重液分选法是伟晶岩型锂矿床探矿的重要指示方法。

赣南铁山垅一带水系沉积物地球化学特征及找矿方向探讨

本文基于对铁山垅一带1∶5万水系沉积物测量工作,分析测试了19种元素,并分析总结了各元素地球化学的分布特征、异常特征。结果表明,该区W、Bi、As、Sb、Bi、Co、Se等元素相对富集,Hg、Ag等元素亏损较强;根据元素组合的特征,可将元素分为四组,即W、Sn、Mo、Bi、F高温元素组合,Cu、Pb、Zn、Cd中温元素组合,Au、Ag、As、Sb、Hg低温元素组合,Mn、Cr、Co、Ni亲铁元素组合;圈定了综合异常22处,找矿远景区2处;在铁山垅—白鹅钨铜多金属找矿远景区可主攻石英脉型钨铜多金属矿,石下—胎子岽钨找矿远景区可主攻隐爆角砾岩型钨矿。

湖南宜章长城岭测区地球化学异常特征及找矿前景

长城岭测区位于南岭成矿带与钦杭成矿带叠合部位的长城岭矿田内,成矿地质条件优越。该地区主要发育Li、Rb、Cs、Be、Pb、Zn、Ag、Sb、Sn等有色稀有金属矿化。1∶10000土壤地球化学测量结果显示:Li、Rb为区内主成矿元素,具明显浓集趋势,具备一定成矿潜力,测区共圈定综合异常7处。通过异常查证及探矿工程揭露,认为长城岭测区具良好的锂铷矿找矿前景,为该地区下一步综合地质找矿工作提供了科学依据。

河南嵩县九仗沟金矿床地球化学特征与勘查模式

九仗沟金矿位于熊耳山—外方山矿集区内的蛮峪—店房金矿带北段,是典型的大型构造蚀变岩型金矿床。采用1/5万水系沉积物测量圈定了找矿靶区,1/1万土壤地球化学测量确定了矿化富集部位,岩石地球化学(原生晕)测量识别出构造破碎带和矿化强度,并预测矿体相对剥蚀程度。研究表明:不同尺度地球化学测量为该金矿勘查提供了不同阶段的找矿信息,找矿效果显著。其中,利用水系沉积物测量在九仗沟矿区范围内圈定了11-丙-Au异常,利用土壤地球化学测量发现了九仗沟1-甲_(1)-Au-Ag-Pb-Cu-Hg-As-Bi-Ni异常,利用原生晕剖面微量元素峰值部位确定了F_(1)构造矿化蚀变带。通过总结该矿床地球化学异常特征和找矿标志,建立了勘查地球化学模式,为区域及矿区周边相同类型的金矿勘查提供理论指导。