TY - JOUR

T1 - Hydrothermal fluid evolution in collisional Miocene porphyry copper deposits in Iran

T2 - Insights into factors controlling metal fertility

AU - Zarasvandi, Alireza

AU - Rezaei, Mohsen

AU - Raith, Johann G.

AU - Asadi, Sina

AU - Lentz, David

PY - 2019/2/1

Y1 - 2019/2/1

N2 - The Cenozoic Urumieh-Dokhtar Magmatic Belt (UDMB) in Iran is considered as one of the major Cu-bearing regions in the world with high potential for the occurrence of giant/large porphyry Cu ± Mo ± Au systems. In the UDMB, porphyry Cu mineralization is strictly associated with Miocene intrusions originating mostly from collisional-related partial melting of subduction-modified juvenile lower crust. In this study fluid inclusion coupled with laser Raman analysis is used to characterize and compare the fluid evolution of the large Meiduk deposit and smaller low grade porphyry copper systems (e.g., Keder, Sarkuh, and Iju) in the UDMB. It can be shown that enhancement of metal fertility of a porphyry system is controlled by several factors: (1) The salinity of early hydrothermal ore fluids; maximum ore-efficiency is seen in porphyry deposits showing supersaturation of NaCl in the pristine high temperature fluids (e.g., Meiduk), (2) Presence of CO 2 and fast exhausting of CO 2 vapor components during early stages of mineralization, (3) Temperature decrease especially during the main ore stage, and (4) High oxygen fugacity (near to the magnetite – hematite oxygen buffer) of the most primitive fluids in the early stages of hydrothermal system.

AB - The Cenozoic Urumieh-Dokhtar Magmatic Belt (UDMB) in Iran is considered as one of the major Cu-bearing regions in the world with high potential for the occurrence of giant/large porphyry Cu ± Mo ± Au systems. In the UDMB, porphyry Cu mineralization is strictly associated with Miocene intrusions originating mostly from collisional-related partial melting of subduction-modified juvenile lower crust. In this study fluid inclusion coupled with laser Raman analysis is used to characterize and compare the fluid evolution of the large Meiduk deposit and smaller low grade porphyry copper systems (e.g., Keder, Sarkuh, and Iju) in the UDMB. It can be shown that enhancement of metal fertility of a porphyry system is controlled by several factors: (1) The salinity of early hydrothermal ore fluids; maximum ore-efficiency is seen in porphyry deposits showing supersaturation of NaCl in the pristine high temperature fluids (e.g., Meiduk), (2) Presence of CO 2 and fast exhausting of CO 2 vapor components during early stages of mineralization, (3) Temperature decrease especially during the main ore stage, and (4) High oxygen fugacity (near to the magnetite – hematite oxygen buffer) of the most primitive fluids in the early stages of hydrothermal system.

KW - Fluid inclusion

KW - Hydrothermal fluids

KW - Iran

KW - Laser Raman spectroscopy

KW - Porphyry copper system

KW - Urumieh-Dokhtar Magmatic Belt

UR - http://www.scopus.com/inward/record.url?scp=85059354253&partnerID=8YFLogxK

U2 - 10.1016/j.oregeorev.2018.12.027

DO - 10.1016/j.oregeorev.2018.12.027

M3 - Article

AN - SCOPUS:85059354253

VL - 105.2019

SP - 183

EP - 200

JO - Ore geology reviews

JF - Ore geology reviews

SN - 0169-1368

IS - February

ER -