期刊
出版社
NATL ACAD SCIENCES
DOI: 10.1073/pnas.2116380119
关键词
garnet; oxygen isotope; magmatic fluid; meteoric water; lode gold deposit
资金
- Ministry of Science and Technology of China [2016YFC0600104]
- National Natural Science Foundation of China [41325007]
- Fundamental Research Funds for National University, China University of Geosciences (Wuhan)
- NSF [EAR -2004618]
- University of Wisconsin -Madison
This study demonstrates the crucial role of magmatic hydrothermal fluids and their mixing with meteoric water in the formation of the Dongping gold deposit in the North China Craton. The findings highlight the potential use of in situ oxygen isotope analysis of garnet in tracing the origin and evolution of hydrothermal fluids in the Earth's crust that may have formed other giant ore deposits.
Lode gold deposits, which are currently the world's major gold supply, have been shown to be generated mostly by phase separation of metamorphic fluids and/or interaction between these fluids and wall rocks. Here we use garnet oxygen isotopes by secondary ion mass spectrometry to document the crucial role of magmatic hydrothermal fluids and their mixing with meteoric water in the formation of the world-class Dongping gold deposit in the North China Craton. Garnet grains from quartz veins of various paragenetic stages and the mineralized alteration envelope at Dongping have dynamic delta O-18 variations of 3.8 to 211.0%, with large intragrain fluctuations up to 5.3%. These values correspond to calculated delta O-18 values of 6.1 to 29.1% for the hydrothermal fluids from which the garnet formed. The isotope data, notably the cyclic alternation in delta O-18 within individual garnet grains, are best interpreted to reflect multiple pulses of magmatically derived fluids and subsequent mixing of each pulse with variable amounts of meteoric water. The results presented here allow us to quantify the significant interplay between magmatic hydrothermal fluids and meteoric water that spanned the entire mineralization history and triggered gold deposition of a lode gold deposit. This study highlights the potential use of in situ oxygen isotope analysis of garnet in tracing the origin and evolution of hydrothermal fluids in the Earth's crust that may have formed other giant ore deposits.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据