Origin and Evolution of the Um Egat and Dungash Orogenic Gold Deposits, Egyptian Eastern Desert: Evidence from Fluid Inclusions in Quartz

Geologic and Metallogenic Framework of North Africa

“…9 and 10 Klemm et al 2001;Zoheir et al 2008Zoheir et al , 2014. In Morocco, intrusion-related gold occurrences are represented by the Iourirn-Akka and Tiouit deposits in the Anti-Atlas Mountains, and by the recently discovered Tamlalt-Menhouhou prospect (Pelleter et al 2008) in the eastern High Atlas.…”

“…These temporal relationships suggest a key role for granite-derived hydrothermal fluids in forming the quartz-vein system. However, structural constraints indicate that the gold-bearing quartz veins developed late in the orogenic cycle of the ANS (e.g., Klemm et al 2001;Zoheir et al 2008;Khalil et al this volume). Indeed, Re-Os age dating of molybdenite from the neighboring Ad Duwayhi gold deposit in western Saudi Arabia has yielded ages of 655.6 ± 2.7 and 649.9 ± 2.3 Ma, recording a late Neoproterozoic timing for that gold mineraliszation (Doebrich et al 2004).…”

“…Similar to the Archean-Paleoproterozoic, the Neoproterozoic era represents an especially fertile time period during which major deposits formed within all Precambrian shields in this part of the African continent. The best documented Neoproterozoic deposits include: (1) orthomagmatic Fe-Ni-Cu-Cr-PGE ores associated with fragments of Pan-African dismembered ophiolitic complexes in the Eastern Desert of Egypt and northeastern Sudan (Abd El-Rahman et al 2009;El-Taher 2010;Hamdy and Lebda 2011;Ahmed et al 2012a, b), in the Bou Azzer district in the central Anti-Atlas orogen of Morocco, and Pan-African serpentinites in the Amsaga, Agane, and Gouérarate areas of the Reguibat Shield and axial zone of the Mauritanides Belt (Ould Moctar et al 2014;Markwitz et al 2015); (2) VHMS deposits that occur along the length of the Red Sea coast from Egypt through Sudan to Eretria (Barrie et al this volume), and in Mali (Markwitz et al 2015); (3) granitoid-and related pegmatite-hosted TaNb-Sn-W ± REE deposits in the Eastern Desert of Egypt (i.e., Abu Dabbab and Nuweibi) and Algeria (Melcher et al 2015;Marignac et al this volume); (4) BIF occurrences in the central part of Egypt (Basta et al 2011;Stern et al 2013;Khalil et al 2015); and (5) orogenic and intrusion-related gold-bearing quartz veins in regional mega-shear structures, including TirekAmesmessa in Algeria (Ferkous and Monie 2002;Marignac et al this volume), deposits in Egypt and Sudan that fringe the Red Sea (El Boushi 1972;Klemm et al 2001;Zoheir et al 2008Zoheir et al , 2014, and the Iourirn-Akka and Tiouit deposits of the Anti-Atlas Mountains in Morocco (Maacha et al 2011a, b, c, d;Bouabdellah et al this volume). Some mineralization related to the Bou Azzer five-element (Co-Ni -Fe-As ± Au ± Ag) and Imiter Ag-Hg deposits also formed during this time span (Bouabdellah et al this volume).…”

“…Considered together, the presence of these two major ore deposits demonstrates the high mineral potential of the two lithotectonic domains. The importance of Archean terranes as the host for gold producers in Africa is further highlighted by productivity of the Zimbabwe and Kaapvaal cratons in southern Africa (e.g., Foster and Piper 1993), and more importantly by the recent discoveries of orogenic and related granitoid-hosted gold deposits in Neoproterozoic terranes of North Africa (i.e., ANS-hosted Um Egat and Dungash deposits in southeastern Egypt; Klemm et al 2001;Zoheir et al 2008;Khalil et al this volume) and the world-class Amesmessa-Tirek gold field in the Hoggar Shield in Algeria (Ferkous and Monie 2002;Marignac et al this volume).…”

Controls on lode gold mineralization, Romite deposit, South Eastern Desert, Egypt

“…Gold in the majority of these localities is present in milky or gray quartz veins with abundant pyrite and arsenopyrite. The distribution of gold occurrences in the Eastern Desert is controlled by major wrench faults and shear zones (e.g., Loizenbauer and Neumayr, 1996;Helmy et al, 2004;Zoheir et al, 2008;Zoheir, 2011). Gold deposits across the southern part of the Eastern Desert are mostly related to NW-or NNW-striking shear zones generally reflecting reactivated earlier accretionary suture zones (e.g., Kusky and Ramadan, 2002;Zoheir, 2008aZoheir, ,b, 2011.…”