The origin of the Tongkeng-Changpo tin deposit,Dachang metal district,Guangxi, China: clues from fluid inclusions and He isotope systematics

Tongkeng-Changpo is the largest tin deposit within the giant Dachang polymetallic tin ore field in Guangxi, southern China, which is part of a large skarn system associated with Cretaceous granitoids. The Tongkeng-Changpo mineralization consists of veins and stockworks in the upper levels and replacement stratiform orebodies (mantos) at lower levels. Based on textural relationships, three major mineralizing stages can be recognized: stage I with cassiterite, sulphides, stannite, tourmaline, and quartz; stage II with cassiterite, sulphides, sulphosalts, quartz, and calcite; and stage III with calcite as the main phase. The study of fluid inclusions has shown that there are two main fluid types: CO₂ and NaCl-H₂O. Homogenization temperatures are 270 to 365°C, 210 to 240°C, and 140 to 190°C for stages I, II, and III, respectively. Salinities range from 1 to 7 wt.% NaCl equiv. in the early ore stage and 3 to 10 wt.% NaCl equiv. in the late stages. Laser Raman Spectroscopy indicates that the inclusion fluids in stages I and II were of carbono-aqueous composition, with minor amounts of CH₄ and H₂S, whereas those in stage III were aqueous. Helium isotopic analyses of inclusion fluids indicate that the ³He/⁴He ratios in the ore veins are in between 1.2 to 2.9 Ra (Ra = 1.4 × 10⁻⁶, modern atmospheric ratio), and range from 1.6 to 2.5 Ra in the stratiform orebodies. This range of ³He/⁴He ratios is significantly higher than that of crustal fluids (0.01–0.05 Ra). The similar characteristics of fluid inclusions and their He isotopic composition, as well as age constraints, indicate that the ore veins and stratiform orebodies of the Tongkeng-Changpo deposit formed from the same hydrothermal system, likely related to granite intrusions of the Mesozoic Yanshanian tectono-thermal event. In addition, the high R/Ra ratios indicate a mantle contribution in the ore fluids.     

新疆西南天山川乌鲁铜、金、锑多金属矿地质特征及成矿规律

新疆西南天山川乌鲁铜、金、锑多金属矿位于塔里木板块北缘活动带.矿体环绕科克莫依纳克岩株内外接触带分布,严格受接触带控制,同时受围岩图尤克阿秀组和次级构造节理、裂隙的控制,其成矿物质来源于图尤克阿秀组和科克莫依纳克岩株.岩浆侵入活动是该矿成矿物质置换萃取和矿液运移的热动力来源.该矿床成因类型为接触交代-夕卡岩型.     

航天遥感技术在叶尔羌河中下游地区Au、Cu等多金属矿找矿有利地段预测中的应用研究

板块构造成矿理论认为西昆仑叶尔羌河中下游地区属于Au、Cu及多金属矿成矿远景区,但因其野外地质条件恶劣,交通状况差,地质勘探极其困难而影响了找矿工作的深入开展,为此我们利用航天遥感技术的优势进行了找矿有利地段预测研究。在研究中首先对区域地质遥感影像特征进行了综合分析,并根据板块构造成矿理论对矿化作用进行了空间划分和成矿条件总结。在此基础上,通过成矿相关影像特征信息的提取,圈定出Au、Cu及多金属矿成矿有利地段。     

南京栖霞山大型铅锌银多金属矿床的发现及其找矿远景

南京栖霞山铅锌银多金属矿床是目前华东地区最大的铅锌银矿床,其成因类型为“断褶带内碳酸盐岩建造中的双循环热（卤）水后成层控型矿床。矿床的发现发展经历了单一锰矿找矿阶段、铅锌矿找矿阶段和银、金矿找矿阶段,并已逐步进入铜矿找矿阶段。几十年来,随着找矿工作的不断深入,矿种不断增高,储量不断扩大,矿床经济价值不断提高。此种发展趋势还将继续,并有可能发现铅等新矿种。     

黑龙江大兴安岭地区雄关多金属矿区地质特征及找矿远景

黑龙江省大兴安岭地区雄关矿区位于大兴安岭北段伊勒呼里山北坡,处于德尔布干多金属成矿带上。区内地层为中生代侏罗纪白音高老组和白垩纪光华组,构造条件比较复杂,岩浆活动十分强烈,地球物理、地球化学异常特征明显,成矿条件优越,是寻找热液型银、铅、锌、钼等多金属矿产的有利地段。     

宁芜地区地质——地球物理综合探矿模型

本文在从事多年综合物探方法找矿的基础上,结合宁芜地区地质矿产及其地球化学特征,总结出了一套地质——地球物理综合探矿模型:用高精度磁测查明断裂构造,圈定矿体和矿化体异常带,利用电法对成矿有利地段的地球化学异常开展激发极化法异常查证,配合电测深和电磁测深法查明异常体的地下展布,合理布置钻探工作。利用该探矿模型在尖山～荞麦山勘查区取得了较好的找矿效果,对宁芜地区寻找多金属矿有较好的指导意义。     

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.     

内蒙黄岗梁—孟恩陶勒盖多金属矿床同位素地质特征

通过内蒙黄岗梁—孟恩陶勒盖多金属矿床稳定同位素地质特征的研究,对成矿物质来源进行了探讨。硫有两个硫源,其一为上地幔岩浆硫,其二为多种成因的地壳硫。铅为正常铅,为来自于地槽区深部岩浆的造山带型铅。根据稳定同位素特征和成矿地质背景,将区内矿床分为Sn、Ag、Cu、Pb、Zn与W、Sn、Be、Fe两个成矿系列。成矿流体主要来源于岩浆水和大气降水。成矿物质主要来源于重熔、同熔两大系列岩浆,岩浆-大气降水对流循环攫取了二叠纪地层中部分矿质参与成矿。     

西藏冈底斯地块北缘甲岗雪山钨-钼-铋-铜-金多金属矿床地质特征及成因初步研究

冈底斯地块南北缘是西藏重要的多金属成矿区之一，在该地块北部首次发现的甲岗钨-钼-铋-铜金多金属矿床是不同于其南部斑岩型铜多金属矿床的成矿新类型，该矿床的发现是藏北地区内生金属矿找矿的重要突破。目前，矿区内共发现规模大、品位高、易采易选的黑钨矿-辉钼矿-石英脉10余条。脉体赋存于区内白云母二长花岗岩的内外接触带，并以内带为主。通过对矿脉等的同位素、包裹体等的初步研究表明，矿床的形成与喜山早期碰撞型中酸性岩浆活动有密切联系，属典型的岩浆气液充填型黑钨矿-石英大脉型矿床。该矿床的发现对进一步认识印度与欧亚大陆碰撞造山过程中的成矿作用特点具有重要意义。     

粤东莲花山断裂带韧性剪切的温压条件及其对钨锡铜多金属成矿作用的约束

广东莲花山断裂带西南段分布有棉洋-双华(Ⅰ)、北山嶂-九龙嶂(Ⅱ)、五指嶂-锅子嶂(Ⅲ)、梅陇-鲘门-观音山(Ⅳ)4条韧性剪切带,呈巨型构造透镜体沿北东向展布。已有研究表明韧性剪切带与本区钨、锡、铜多金属成矿作用关系密切,控制着矿床的空间分布,是重要含矿、控矿构造。按照变质程度和矿物组成,区内韧性剪切带由核部至边部可以划分为石英透镜体→石榴子石(堇青石)糜棱岩→糜棱片岩→片岩→原岩等;通过对其中的石榴子石、黑云母等典型矿物进行电子探针分析(EPMA),并利用石榴石-黑云母地质温压计估算了 4条韧性剪切带形成的温压条件,它们分别为484～526℃/4.92～7.72kbar、458～469℃/2.17 ～2.67kbar、536～551 ℃/1.28～1.67kbar、512～516℃/4.38 ～4.87kbar,与区内变质岩野外地质变形、变质特征相吻合,且火山岩为主的地区变质压力明显高于花岗岩为主的地区。研究显示,变质条件对区内变质分带和多金属成矿作用有明显的控制,棉洋-双华和梅陇-鲘门-观音山韧性剪切带的压力条件相对较高,金属成矿以钨、锡多金属成矿为主;而北山嶂-九龙嶂和五指嶂-锅子嶂韧性剪切带的压力相对较低,金属成矿则以铜、铅、锌成矿为主。