Cu isotopes reveal initial Cu enrichment in sources of giant porphyry deposits in a collisional setting

Yuan-Chuan Zheng, Sheng-Ao Liu, Chang-Da Wu, William L. Griffin, Zhen-Qing Li, Bo Xu, Zhi-Ming Yang, Zeng-Qian Hou, Suzanne Y. O'Reilly

Research output: Contribution to journalArticleResearchpeer-review

Abstract

Porphyry copper deposits (PCDs) represent the most important type of Cu reservoir on Earth, but the mechanism of Cu enrichment in PCDs is debated due to the lack of direct constraints. This issue may be resolved by the study of copper isotopes (δ65Cu), which are strongly fractionated during formation and/or precipitation of sulfides. Here we report high-precision Cu-isotope data on a large set of porphyries, mafic magmatic enclaves (MMEs), and sulfide ores from PCDs in southern Tibet. For comparison, barren intrusions from southern Tibet were also analyzed. The fertile porphyries and MMEs from PCDs have high Cu contents and elevated δ65Cu values compared with the barren intrusions and global average felsic rocks. These features are inconsistent with the known supergene processes after sulfide formation (e.g., leaching and weathering). Because sulfides formed from secondary Cu-rich fluids are enriched in heavy Cu isotopes, the elevated Cu contents and Cu-isotope ratios indicate that the Cu source for PCDs was a refertilized lithosphere enriched in sulfides. This suggests that initial Cu enrichment in magma sources could be a key step in the formation of giant PCDs in continental collision zones.

LanguageEnglish
Pages135-138
Number of pages4
JournalGeology
Volume47
Issue number2
Early online date31 Dec 2018
DOIs
Publication statusPublished - 1 Feb 2019

Fingerprint

porphyry
isotope
copper
sulfide
enclave
supergene process
collision zone
felsic rock
continental collision
lithosphere
weathering
magma
leaching
fluid

Cite this

Zheng, Yuan-Chuan ; Liu, Sheng-Ao ; Wu, Chang-Da ; Griffin, William L. ; Li, Zhen-Qing ; Xu, Bo ; Yang, Zhi-Ming ; Hou, Zeng-Qian ; O'Reilly, Suzanne Y. / Cu isotopes reveal initial Cu enrichment in sources of giant porphyry deposits in a collisional setting. In: Geology. 2019 ; Vol. 47, No. 2. pp. 135-138.
@article{a090b8d43f83452781254be3d1457661,
title = "Cu isotopes reveal initial Cu enrichment in sources of giant porphyry deposits in a collisional setting",
abstract = "Porphyry copper deposits (PCDs) represent the most important type of Cu reservoir on Earth, but the mechanism of Cu enrichment in PCDs is debated due to the lack of direct constraints. This issue may be resolved by the study of copper isotopes (δ65Cu), which are strongly fractionated during formation and/or precipitation of sulfides. Here we report high-precision Cu-isotope data on a large set of porphyries, mafic magmatic enclaves (MMEs), and sulfide ores from PCDs in southern Tibet. For comparison, barren intrusions from southern Tibet were also analyzed. The fertile porphyries and MMEs from PCDs have high Cu contents and elevated δ65Cu values compared with the barren intrusions and global average felsic rocks. These features are inconsistent with the known supergene processes after sulfide formation (e.g., leaching and weathering). Because sulfides formed from secondary Cu-rich fluids are enriched in heavy Cu isotopes, the elevated Cu contents and Cu-isotope ratios indicate that the Cu source for PCDs was a refertilized lithosphere enriched in sulfides. This suggests that initial Cu enrichment in magma sources could be a key step in the formation of giant PCDs in continental collision zones.",
author = "Yuan-Chuan Zheng and Sheng-Ao Liu and Chang-Da Wu and Griffin, {William L.} and Zhen-Qing Li and Bo Xu and Zhi-Ming Yang and Zeng-Qian Hou and O'Reilly, {Suzanne Y.}",
year = "2019",
month = "2",
day = "1",
doi = "10.1130/G45362.1",
language = "English",
volume = "47",
pages = "135--138",
journal = "Geology",
issn = "1943-2682",
publisher = "Geological Society of America",
number = "2",

}

Cu isotopes reveal initial Cu enrichment in sources of giant porphyry deposits in a collisional setting. / Zheng, Yuan-Chuan; Liu, Sheng-Ao; Wu, Chang-Da; Griffin, William L.; Li, Zhen-Qing; Xu, Bo; Yang, Zhi-Ming; Hou, Zeng-Qian; O'Reilly, Suzanne Y.

In: Geology, Vol. 47, No. 2, 01.02.2019, p. 135-138.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Cu isotopes reveal initial Cu enrichment in sources of giant porphyry deposits in a collisional setting

AU - Zheng, Yuan-Chuan

AU - Liu, Sheng-Ao

AU - Wu, Chang-Da

AU - Griffin, William L.

AU - Li, Zhen-Qing

AU - Xu, Bo

AU - Yang, Zhi-Ming

AU - Hou, Zeng-Qian

AU - O'Reilly, Suzanne Y.

PY - 2019/2/1

Y1 - 2019/2/1

N2 - Porphyry copper deposits (PCDs) represent the most important type of Cu reservoir on Earth, but the mechanism of Cu enrichment in PCDs is debated due to the lack of direct constraints. This issue may be resolved by the study of copper isotopes (δ65Cu), which are strongly fractionated during formation and/or precipitation of sulfides. Here we report high-precision Cu-isotope data on a large set of porphyries, mafic magmatic enclaves (MMEs), and sulfide ores from PCDs in southern Tibet. For comparison, barren intrusions from southern Tibet were also analyzed. The fertile porphyries and MMEs from PCDs have high Cu contents and elevated δ65Cu values compared with the barren intrusions and global average felsic rocks. These features are inconsistent with the known supergene processes after sulfide formation (e.g., leaching and weathering). Because sulfides formed from secondary Cu-rich fluids are enriched in heavy Cu isotopes, the elevated Cu contents and Cu-isotope ratios indicate that the Cu source for PCDs was a refertilized lithosphere enriched in sulfides. This suggests that initial Cu enrichment in magma sources could be a key step in the formation of giant PCDs in continental collision zones.

AB - Porphyry copper deposits (PCDs) represent the most important type of Cu reservoir on Earth, but the mechanism of Cu enrichment in PCDs is debated due to the lack of direct constraints. This issue may be resolved by the study of copper isotopes (δ65Cu), which are strongly fractionated during formation and/or precipitation of sulfides. Here we report high-precision Cu-isotope data on a large set of porphyries, mafic magmatic enclaves (MMEs), and sulfide ores from PCDs in southern Tibet. For comparison, barren intrusions from southern Tibet were also analyzed. The fertile porphyries and MMEs from PCDs have high Cu contents and elevated δ65Cu values compared with the barren intrusions and global average felsic rocks. These features are inconsistent with the known supergene processes after sulfide formation (e.g., leaching and weathering). Because sulfides formed from secondary Cu-rich fluids are enriched in heavy Cu isotopes, the elevated Cu contents and Cu-isotope ratios indicate that the Cu source for PCDs was a refertilized lithosphere enriched in sulfides. This suggests that initial Cu enrichment in magma sources could be a key step in the formation of giant PCDs in continental collision zones.

UR - http://www.scopus.com/inward/record.url?scp=85060483766&partnerID=8YFLogxK

U2 - 10.1130/G45362.1

DO - 10.1130/G45362.1

M3 - Article

VL - 47

SP - 135

EP - 138

JO - Geology

T2 - Geology

JF - Geology

SN - 1943-2682

IS - 2

ER -