New Economic Geology paper published on the Neoproterozoic Jebel Ohier Porphyry Copper Deposit – Sudan

    Published on January 21st, 2020

    CSA Global congratulates author, Frank P Bierlein (QMSD Mining Co. Ltd), and co-authors, Warren Potma (CSA Global), Frederico Cernuschi (CSA Global, Eclectic Rock), Dr Carl Brauhart (CSA Global), Jamie Robinson (CSA Global), Chris J Barmann (QMSD Mining Co. Ltd), Warwick Bullen (Qatar Mining), Jose F. Henriquez (QMSD Mining Co. Ltd), Ian Davies (QMSD Mining Co. Ltd), and Allen Kennedy (John de Laeter Centre, Curtin University) on their recently published paper: ‘New Insights into the Evolution and Age of the Neoproterozoic Jebel Ohier Porphyry Copper Deposit, Red Sea Hills, Northeastern Sudan’ published in Economic Geology by the Society of Economic Geologists.

    Abstract:
    New SHRIMP U-Pb data from dioritic to granodioritic synmineral intrusions associated with the Jebel Ohier porphyry copper deposit (mineral inventory, including NI43-101-compliant total inferred and indicated resources, of 593 million tonnes [Mt] at 0.33% Cu and 0.05 ppm Au, for 1.953 Mt of contained Cu and 933,600 oz of Au at 0.15% Cu cutoff) in the Red Sea Hills of northeastern Sudan have bracketed the age of mineralization to ca. 816 to 812 Ma. This age range, as well as constraints from new and existing lithogeochemical data, is consistent with the deposit’s formation from a productive parental magma source during the early stages in the evolution of an intra-Mozambique Ocean island arc.

    The Jebel Ohier porphyry copper deposit bears many similarities to well documented Phanerozoic analogues elsewhere in terms of (1) the mapped style and zonation of hydrothermal alteration (i.e., proximal K-silicate–dominated, to sericitic, to distal propylitic alteration), (2) the occurrence of intense Cu-bearing A- and B-type vein stockwork, as well as sulfide-only C-type veins, anhydrite veins, and younger, peripheral D-type veins, and (3) the geochemical fingerprint of the associated porphyry, which is akin to those of ore-related Tertiary porphyries in the Escondida area in northern Chile.

    The multiphase intrusion hosting the Jebel Ohier porphyry copper deposit has been intruded by several generations of mafic to felsic postmineralization dikes and voluminous plutons, with a peak in magmatic activity coinciding with the suturing of the Gebeit terrane at ca. 724 Ma. In spite of, or perhaps because of, the occurrence of extensive postmineralization magmatism, and regardless of subsequent deformation, regional metamorphism, uplift, and erosion, the deposit has remained remarkably intact. The discovery of a relatively ancient, yet well-preserved porphyry copper deposit in the Neoproterozoic Arabian-Nubian Shield has major implications for the exploration potential of this resource-rich geologic terrain.

    The academic paper published by Economic Geology has been published in Volume 115, Issue 1.

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    PUBLISHED BY SOCIETY OF ECONOMIC GEOLOGISTS
    ECONOMIC GEOLOGY
    VOLUME 115, NUMBER 1, JANUARY 2020

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