The Setting and Timing of Copper Mineralization in the Timna Igneous Complex, southern Israel.

The absence of primary sulfides challenges the interpretation of metal ore genesis, particularly where ore is hosted within several separate stratigraphic horizons. In the Timna Valley, S Israel, copper ore bodies occur mostly in Cambrian and Cretaceous sandstones and rarely in the underlying late Neoproterozoic Timna igneous complex (TIC), as secondary Cu-sulfides in veins and nodules and more abundantly as Cu-hydroxides. The timing and setting of copper mineralization in the TIC and its relation to the sedimentary ore are unknown. Quartz phenocryst-hosted fluid inclusion assemblages (FIA) in quartz porphyry (QP) stock and dykes are associated with sulfide inclusions of pyrite, chalcocite, and chalcopyrite, indicating a magmatic-hydrothermal genetic relationship. Mineralization-associated fluid inclusion assemblages (FIAs) in QP are: (FIA.a) <12 wt% NaCl eq., CO2 vapor-rich arrays with and homogenization temperatures (Ths) of 270­­­­­­­­­­­­–500°C; ­­­­­(FIA.b) immiscible 30–35 wt%. NaCl eq. aqueous liquid and a CO2 vapor-rich fluid trapped at 193–266°C; (FIA.c) secondary H2O liquid-rich arrays (0-11 wt% NaCl eq.), Th of 115–256 ⁰C. Mineralization-associated zircon and rutile in QP yielded U–Pb ages of ~595 Ma, overlapping alkaline felsic dykes in S Israel. Rapid cooling below 220°C is evident by average rutile (U–Th)/He age of 595 ± 46 Ma found in QP and adjacent quartz monzonite and porphyritic granite. Zircon (U–Th)/He ages record Carboniferous heating at 180 ⁰C ≤ T ≤ 220 ⁰C and hydrothermal alteration. This indicates temperatures in the TIC did not exceed ~180 ⁰C after the Carboniferous. Primary copper mineralization in the TIC is attributed to QP emplacement, during A-type granite intrusions, possibly scavenging copper and other metals from earlier calc-alkaline crust. This was followed by lower temperature (<220°C) hydrothermal events.