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巨型斑岩型铜矿的最佳岩浆氧化条件
作者:小柯机器人 发布时间:2025/1/4 16:13:16

中国科学院地球化学研究所朱经经课题组报道了巨型斑岩型铜矿的最佳岩浆氧化条件。相关论文于2025年1月2日发表在《科学通报》上。

在这项工作中,研究人员进行了数值模拟,结果表明S2-在ΔFMQ +1条件下,Cu占总硫的比重约为90%,在ΔFMQ +2和ΔFMQ +3条件下分别降至33%-38%和15%-25%。从ΔFMQ +1到ΔFMQ +3, Cu的析出效率降低了88%-96%。

岩石学模型进一步表明,Cu的最大沉淀效率(以及Cu的禀赋)发生在ΔFMQ +1附近。因此,研究结果强调中度氧化岩浆(ΔFMQ = ~1),而不是高度氧化岩浆(ΔFMQ >~2)是生成巨型PCD的最佳选择。

据研究人员介绍,目前普遍认为,斑岩型铜矿床(PCDs)的形成需要中至高度氧化的岩浆。然而,只有少数研究试图探讨不同岩浆fO2值对PCDs形成的影响。根据前人的研究,巨型PCDs岩浆氧逸度主要集中在ΔFMQ 0.5 ~ ΔFMQ +2.5之间,其中第一个四分位数为+0.8,中位数为+1.3,第三四分位数为+1.7。

附:英文原文

Title: Optimal magmatic oxidation conditions for giant porphyry copper deposits

Author: Jing-Jing Zhu a

Issue&Volume: 2025/01/02

Abstract: It is widely accepted that moderately to highly oxidized magmas are needed to form porphyry copper deposits (PCDs). However, only a few studies have attempted to investigate the effects of variable magmatic fO2 values on the formation of PCDs. Based on previously published studies, the magma oxygen fugacity of giant PCDs is mainly concentrated between ΔFMQ 0.5 and ΔFMQ +2.5, with the first quartile, median, and third quartile being +0.8, +1.3, and +1.7, respectively.

In this work, we have carried out numerical modeling, which shows that the S2- used to precipitate Cu accounts for approximately 90% of total sulfur at ΔFMQ +1 but drops to 33%–38% and 15%–25% at ΔFMQ +2 and ΔFMQ +3, respectively. This leads to a decrease of 88%–96% in Cu precipitation efficiencies from ΔFMQ +1 to ΔFMQ +3. Our petrological model further shows that the maximum Cu precipitation efficiency (and, therefore, Cu endowments) occurs at around ΔFMQ +1. We, therefore, highlight that moderately oxidized magma (ΔFMQ = ~1) rather than highly oxidized ones (ΔFMQ > ~2) is optimal for the generation of giant PCDs.

DOI: 10.1016/j.scib.2024.12.048

Source: https://www.sciencedirect.com/science/article/abs/pii/S209592732400985X

期刊信息

Science Bulletin《科学通报》,创刊于1950年。隶属于SciEngine出版平台,最新IF:18.9

官方网址:https://www.sciengine.com/SB/home
投稿链接:https://mc03.manuscriptcentral.com/csb


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