投稿时间：2015-05-01
修订日期：2016-02-24
网络发布日期：2016-04-29
中文摘要:滇西北衙超大型金多金属矿床通过先后开展五期详查,获得了找矿重大突破,金矿规模达到超大型,共伴生铅、锌、银、铜、铁、硫矿也达到大型-特大型规模。文章在近十年的勘查工作实践及综合研究矿床模型的基础上,总结了矿床的成矿地质条件、地球物理勘查模型、地球化学勘查模型和地质找矿标志。研究表明:喜马拉雅期富碱斑岩是矿床形成最关键的控矿因素,马鞍山断裂控制了区内喜马拉雅期富碱斑岩的产出,北衙向斜控制了矽卡岩矿体和其他矿体的产出,矿床定位受控于喜马拉雅期富碱斑岩与三叠系中统北衙组(T2b)碳酸盐岩接触的矽卡岩带以及内、外接触带,属于与喜马拉雅期富碱斑岩有关的矽卡岩-热液型金多金属矿床,并在此基础上进一步划分为"二型五类"。矿区1:10 000岩石地球化学勘查模型显示,矿区分布有强金元素异常,浓集中心明显,并有与Ag、Pb、Zn、As、Hg等元素相伴产出的综合异常。1:10 000地球物理勘查模型显示,磁异常面积大、强度高,极大值2000多nT,异常形态规则,总体形态呈椭圆形,梯度变化较大,正负异常相伴,南正北负。斑岩显示为低磁异常,接触带为高磁异常,环状的高磁异常带构成了斑岩与围岩接触带矽卡岩型矿化体,围岩碳酸盐岩为低磁异常。激电在斑岩、矽卡岩型矿体上形成低阻高极化异常,矽卡岩型矿体分布区视极化率5%~8%,视电阻率50~120 Ω·m。大功率激电、可控源音频大地电磁测深对斑岩体及斑岩与围岩接触带(蚀变带)可进行较准确定位。
Abstract:Five rounds of general exploration have been done in the Beiya superlarge Au-polymetallic orefield, northwest of Yunnan. In particular, great breakthroughs have been made through ore exploration in Wandongshan ore block, where gold resources have extended to be supergiant scale. Accompanied Pb, Zn, Ag, Cu, Fe and S resources are all estimated to be superlarge-large scale. This paper, based on previous exploration and researches, summarizes the geological conditions for the formation of the deposit, the geophysical model, the geochemical model and the geological targeting methods. Some conclusions have been reached: ① The Himalayan alkali-rich porphyries should be the key factor for the formation of the deposit; ② the Ma'anshan Fault controls the emplacement of the Himalayan porphyries; ③ the Beiya syncline controls the occurrence of the skarn orebodies and other orebodies; ④ ore deposit positioning is mainly located at the skarn zone between Himalayan alkali-enriched porphyry and carbonates of Triassic Beiya (T2b) Formation, as well as inner and outer contact zone of the porphyry. According to these discoveries, this deposit was classified as porphyry-skarn Au-polymetallic deposit associated with Himalayan alkali-rich porphyries, which helped the authors further recognize two main ore types with five subclasses. The 1:10 000 soil geochemical exploration targeting model of the Beiya district shows a strong Au anomaly in this area, with an obvious core for elemental concentration, and a synthetic anomaly reflected by the associated Ag, Pb, Zn, As and Hg. With the 1:10 000 geophysical targeting model, a strong magnetic anomaly, which has a maximum value of more than 2000 nT, was identified. This anomaly covers a large area and its shape is regular, generally like an oval. Moreover, it has a sharp gradient with both positive and negative anomalies, and tends to be positive in the south and negative in the north. Porphyries show low magnetic anomaly while the contact zone shows strong magnetic anomaly. The circular high magnetic anomaly belt constitutes the mineralization belt of the contact zone between porphyry and wall-rock. Electrical stimulation caused a low resistance, and high polarization anomalies were shown in the porphyry-type and the skarn-type orebodies. In these orebodies, the apparent chargeabilities vary between 5% and 8%, and the apparent resistivities vary from 50 Ω·m to 120 Ω·m. High power electrical stimulation and source-controlled magnetotelluric sounding can precisely position the porphyries and the contact zone between porphyry and wall-rock.
keywords:geology skarn-hydrothermal type Au-polymetallic ore deposit exploration model Beiya western Yunnan
文章编号：
中图分类号：P618.51
文献标志码：
基金项目:本文得到中国地质调查局"云南鹤庆北衙金多金属矿田整装勘查区专项填图与技术应用示范"(编号: 12120114013501)课题、中国地质科学院矿产资源研究所"中国西南地区中新生代斑岩-矽卡岩型铜矿成矿规律与矿床模型"(编号: 12120113093700)课题及云南省"云岭学者"项目联合资助
引用文本：
和中华,官德任,和文言,周云满,符德贵,杨绍文,吕永增,王利东,李万华,苏纲生,杨锐.2016.滇西北衙超大型金多金属矿床勘查模型[J].矿床地质,35(2):261~282HE ZhongHua,GUAN DeRen,HE WenYan,ZHOU YunMan,FU DeGui,YANG ShaoWen,LÜ YongZeng,WANG LiDong,LI WanHua,SU GangSheng,YANG Rui.2016.Exploration model of Beiya superlarge gold-polymetallic deposit, northwestern Yunnan[J].Mineral Deposits35(2):261~282
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