Skip to Main Content
Book Chapter

Chapter 5: Carlin-Type Gold Deposits in the Dian-Qian-Gui “Golden Triangle” of Southwest China

By
Wenchao Su
Wenchao Su
1
State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
Search for other works by this author on:
Wendou Dong
Wendou Dong
1
State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
Search for other works by this author on:
Xingchun Zhang
Xingchun Zhang
1
State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
Search for other works by this author on:
Nengping Shen
Nengping Shen
1
State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
Search for other works by this author on:
Ruizhong Hu
Ruizhong Hu
1
State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
Search for other works by this author on:
Albert H. Hofstra
Albert H. Hofstra
2
U.S. Geological Survey, Mail Stop 963, Box 25046, Denver, Colorado 80225
Search for other works by this author on:
Lianzheng Cheng
Lianzheng Cheng
1
State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
Search for other works by this author on:
Yong Xia
Yong Xia
1
State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
Search for other works by this author on:
Keyou Yang
Keyou Yang
1
State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China
Search for other works by this author on:
Published:
January 01, 2018

Abstract

The Dian-Qian-Gui “Golden Triangle” area of southwest China has the second-largest concentration of Carlin-type gold deposits in the world, containing more than 800 tonnes of Au (25.7 Moz). All of the deposits are located along long-lived, deep-penetrating crustal structures inherited from Devonian rifting of the Precambrian Yangtze craton. They are hosted in Cambrian to Middle Triassic platform carbonate, transitional, and siliciclastic rocks of the Youjiang basin, and locally in Late Permian diabase intrusions or volcaniclastic rocks. These deposits have many characteristics in common with Carlin-type gold deposits in Nevada, USA, including lithology of host rocks, alteration types, elemental associations, and occurrence of gold.

Our recent work has identified two episodes of gold mineralization in the Dian-Qian-Gui area that have distinct geologic settings, radiogenic and stable isotopes, and fluid inclusions. Gold deposits hosted in diabase intrusions along the southern margin of the Youjiang basin formed in the Middle-Late Triassic (232–212 Ma) and have low-salinity (~2 wt % NaCl equiv), high-temperature (~245°C) fluid inclusions with high-density CO2 that are similar to those in orogenic gold deposits. Sediment-hosted gold deposits along the northern margin of the Youjiang basin formed in the Late Jurassic-Early Cretaceous (148–134 Ma) and have moderate salinity (~5 wt % NaCl equiv) and temperature (~210°C) fluid inclusions, with variable CO2, low Fe, and high As, Sb, and Au contents, based on microanalysis of fluid inclusions. Deposits on each margin contain gold-bearing arsenian pyrite and arsenopyrite that precipitated from H2S-rich fluids by sulfidation of Fe minerals in the host rocks. Oxygen and hydrogen isotopes indicate metamorphic fluid sources for deposits on both margins, but sulfur isotopes indicate different sources of reduced sulfur. The narrow range of high δ34S values for arsenian pyrite and arsenopyrite from districts along the southern margin of the Youjiang basin suggests derivation from a sedimentary source. Some of the deposits along the northern margin of the Youjiang basin have δ34S values near zero that permit a magmatic or sedimentary sulfur source, while others have high values indicative of a sedimentary source.

We propose a model in which metamorphic ore fluids were generated by regional metamorphism of sedimentary rocks during the Indosinian orogeny along the southern margin and the Yanshanian orogeny along the northern margin of the Youjiang basin. Metamorphic ore fluids were focused into reactivated basement-penetrating rift faults and flowed upward into structural highs in response to stress relaxation during each orogeny. Gold-bearing sulfides precipitated where the ore fluids reacted with carbonaceous and Fe-rich host rocks and mixed with variably exchanged meteoric ground water.

The pressure-temperature conditions and compositions of ore fluids are intermediate between those of the mesozonal orogenic and the shallow Carlin-type gold systems. The Chinese Carlin-type gold deposits may, therefore, represent a link between orogenic and Carlin-type gold deposits that formed during transitions between compressional and extensional environments.

You do not currently have access to this article.

Figures & Tables

Contents

Reviews in Economic Geology

Diversity in Carlin-Style Gold Deposits

John L. Muntean
John L. Muntean
Ralph J. Roberts Center for Research in Economic Geology, Nevada Bureau of Mines and Geology, University of Nevada Reno
Search for other works by this author on:
Society of Economic Geologists
Volume
20
ISBN electronic:
9781629491189
Publication date:
January 01, 2018

GeoRef

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal