Affiliation:
1. Faculty of Land Resource Engineering, Kunming University of Science and Technology, Kunming 650093, China
2. Southwest Institute of Geological Survey, Geological Survey Center for Non-Ferrous Metals Resources, Kunming 650093, China
3. Ministry of Natural Resources (MNR) Key Laboratory of Metallogeny and Mineral Assessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China
Abstract
The Laoyingqing zinc deposit is located in the Pb-Zn deposit concentration district in northeastern Yunnan, with a geotectonic location on the southwestern edge of the Yangtze block. This deposit occurs in the interlayer fracture zone of the Huangcaoling Formation slate in the Middle Proterozoic Kunyang Group. In this deposit, zinc is significantly enriched compared to lead, and the sulfur isotopic composition of sphalerite shows δ34SCDT close to negative values. These characteristics are different from the common Pb-Zn deposits that occur in Sinian and Carboniferous carbonate rocks in northeastern Yunnan. The genesis of this deposit and its similarities to and differences from other Pb-Zn deposits hosted in carbonate rocks in the Sichuan–Yunnan–Guizhou Pb-Zn metallogenic triangle area (SYGT) need further research. This article selects typical rock (ore) samples for fluid inclusion, trace element, and H–O isotope analyses. The results show that (1) the homogenization temperature of the fluid inclusions is 130~306.5 °C, the salinity is 7.17 wt%~20.67 wt% NaCleq, and the density of the ore-forming fluids is 0.86–1.07 g/cm3. Overall, these ore-forming fluids belong to medium–low-temperature, medium–low-salinity, and medium–low-density ore-forming fluids, and they have reducibility. The fluid pressure is 36.3~85.6 Mpa, and the mineralization depth is 1.34~3.17 km. (2) The ore-forming fluids mainly came from deep-source metamorphic water and basin brine containing organic matter. (3) The ore-forming materials mainly came from the surrounding rocks (Kunyang Group). (4) The trace element characteristics of this deposit are different from sedimentary-exhalative type, magmatic hydrothermal type, and skarn type of Pb-Zn deposits, and have little difference from MVT Pb-Zn deposits. Based on the comprehensive analysis, this deposit is classified as a medium–low-temperature hydrothermal vein-type zinc deposit unrelated to magmatic activity. This study extends the ore-bearing surrounding rocks of Pb-Zn deposits in the SYGT to the slate of the Kunyang Group, enriching the regional Pb-Zn deposit mineralization theory and providing new ideas for mineralization prediction.
Funder
Chinese National Natural Science Foundation
Yunnan Ten Thousand Talents Plan Young & Elite Talents Project
YM Lab Project
Innovation Team of Yunnan Province
Subject
Geology,Geotechnical Engineering and Engineering Geology
Reference68 articles.
1. The source of metals in the Qilinchang Zn-Pb deposit, northeastern Yunnan, China: Pb-Sr isotope constrains;Zhou;Econ. Geol.,2001
2. The Comparison of Mississippi Valley-Type Pb-Zn Deposits in Southwest of China and in Mid-Continent of United States;Wang;Bull. Mineral. Petrol. Geochem.,2002
3. Distribution, characteristics, and genesis of Mississippi Valley-Type lead-zinc deposits in Sichuan-Yunnan-Guizhou area;Zang;Miner. Depos.,2005
4. Deposit model of germanium rich silver lead-zinc polymetallic ore cluster in northeastern Yunnan;Han;J. Geol.,2012
5. Geological Characteristics and Prospecting Prospects of the Laoyingqing Zinc Deposit in Huize County, Yunnan;Yang;Yunnan Geol.,2015