State Key Laboratory of Geological Process and Mineral Resources, China University of Geosciences, Wuhan 430074, China.
School of Earth Resources, China University of Geosciences, Wuhan 430074, China.
Proc Natl Acad Sci U S A. 2022 May 10;119(19):e2116380119. doi: 10.1073/pnas.2116380119. Epub 2022 May 2.
SignificanceThere is a common consensus that lode gold deposits mostly precipitated from metamorphic fluids via fluid boiling and/or fluid-rock interaction, but whether magmatic hydrothermal fluids and the mixing of such fluids with an external component have played a vital role in the formation of lode gold deposits remains elusive. We use garnet secondary ion mass spectrometry oxygen isotope analysis to demonstrate that the world-class Dongping lode gold deposit has been formed by multiple pulses of magmatic hydrothermal fluids and their mixing with large volumes of meteoric water. This study opens an opportunity to tightly constrain the origin of lode gold deposits worldwide and other hydrothermal systems that may have generated giant ore deposits in the Earth's crust.
意义
人们普遍认为，原生金矿主要是通过变质流体的沸腾和/或流体-岩石相互作用沉淀形成的，但岩浆热液以及这种流体与外部成分的混合是否对原生金矿的形成起到了至关重要的作用，目前仍不得而知。我们利用石榴石二次离子质谱氧同位素分析，证明了世界级的东平原生金矿是由多期岩浆热液及其与大量大气水混合形成的。这项研究为全球范围内的原生金矿以及其他可能在地壳中形成巨型矿床的热液系统的起源提供了一个很好的约束机会。
