CSA Global congratulates Dr Frank Bierlein from QMSD Mining Co. Limited, first author, of the recently published academic paper on “Petrogenesis of a Neoproterozoic magmatic arc hosting porphyry Cu-Au mineralization at Jebel Ohier in the Gebeit Terrane, NE Sudan” outlining a new style of mineralisation relatively uncommon to Sudan.
CSA Global, Managing Director of Canada, Dennis Arne and Director of Exploration, Dr Neal Reynolds played an integral role in co-authoring the paper together with Dr Bierlein and representatives from Qatar Mining, Federation University, and the University of Melbourne.
The academic paper published by Elsevier, Ore Geology Reviews, Journal for Comprehensive Studies of Ore Genesis and Ore Exploration seeks to familiarize scientists with advances in a number of interconnected disciplines relating to the field and study of ore deposits.
•Newly discovered porphyry Cu-Au deposit in the Neoproterozoic Red Sea Hills of northeastern Sudan
•System represents first documented porphyry Cu-Au deposit in the NE African portion of the Arabian Nubian Shield
•Bears similarities to major ‘productive’ Tertiary – Cenozoic porphyries in circum-Pacific metallogenic belts
•Deposit formed in supra-subduction setting and during constructional stage of an evolving intra-oceanic magmatic arc
•Ore-forming granodiorite-dacite porphyry complex at Jebel Ohier result of ‘abnormal’, prolonged multi-phase arc plutonism
The ca. 730 Ma porphyry Cu-Au deposit at Jebel Ohier in the Red Sea Hills of northeastern Sudan represents a rare example of a preserved Neoproterozoic magmatic-hydrothermal system which bears many similarities to major mineral-hosting (‘productive’) Tertiary–Cenozoic porphyries in circum-Pacific metallogenic belts. Petrographic, lithogeochemical and Sm-Nd isotope systematics confirm that the deposit formed in a supra-subduction setting and during the constructional stage of an evolving intra-oceanic magmatic arc. The calc-alkaline melts were sourced predominantly from juvenile reservoirs and received comparatively little input from continental-character material. Comparison with igneous rocks from barren intrusions elsewhere in the region point to the absence of major crustal breaks but indicate that the ore-forming granodiorite-dacite porphyry complex at Jebel Ohier is the result of ‘abnormal’ and prolonged multi-phase arc plutonism. This process involved the formation of relatively hydrous and oxidized melts via the fractionation of magmas, which possibly had ponded at the bottom of the thickening lithosphere for a protracted period prior to their ascent. The tectonic trigger for the emplacement of the productive pluton into a pre-existing volcanic edifice at Jebel Ohier remains unconstrained. Preservation of what is considered the first documented porphyry Cu-Au deposit in the NE African portion of the Arabian Nubian Shield can probably be related to the accretion of the magmatic arc to a stable continental margin within a few million years of mineralization, thus enabling the deposit to escape excessive uplift, erosion and structural dismemberment.
The paper was released in May 2016.
BSc (Hons) Geology, MSc, PhD, Grad Diploma
Dennis has over 30 years’ experience in applied geochemistry in a wide range of environments, in both the minerals and the petroleum industries, and as an academic and in geological surveys. For the last 10 years he has been involved as a consultant in the development of geochemical exploration programs for precious and base metals exploration in Australia, North America, South America and Africa.
PhD. , BSc, FAusIMM, MAIG, FSEG
Dr Neal Reynolds is a geologist with almost 30 years’ experience in the mineral exploration industry from project generation to advanced project stage, encompassing targeting studies, project management, project due diligence, audit and optimisation, and expert reporting. Neal has worked on projects globally, with extensive experience in Asia, Africa, and Australia, and is particularly sought after for his specialist expertise in the metallogeny and mining industry in Southeast Asia. He has broad commodity experience and expertise in sediment-hosted and intrusive-related base metals and gold systems. He specialises in integrated mineral systems targeting at district to deposit scale, including the effective application of sedimentary geology, lithostratigraphy, structural geology, and alteration studies.