Re-Os geochronology of gold mineralization in the Fawakhir area, Eastern Desert, Egypt

Abstract

We report the first Re-Os data on gold-associated arsenopyrite from mesothermal gold-quartz veins in the ancient Egyptian Fawakhir-El Sid gold mining district in the central Eastern Desert. This mining district has an~5000-yearold history and is displayed in the Turin Papyrus Map (about 1150 BC), which is widely acclaimed as the world's oldest geographic map, as well as the oldest geologic and mine map. The Fawakhir-El Sid district is part of a regional NNWtrending shear corridor (15 km wide) that hosts several other historic gold mines associated with left-lateral wrench structures and related granite intrusions. Vein-style gold mineralization is hosted within and at the margin of an I-type and magnetite-series monzogranite, the Fawakhir granite intrusion, and a Pan-African (~740 Ma) ophiolite sequence. The ore mineralogy of the mineralized quartz veins includes pyrite-arsenopyrite-pyrrhotite-sphalerite-galena-chalcopyrite-electrum plus a number of tellurides of Ag, Au, and Bi. The 187 Re/ 188 Os versus 187 Os/ 188 Os regression on 5 points of arsenopyrite gives an age of 601 ± 17 Ma with an initial 187 Os/ 188 Os of 0.24 ± 0.07 (2 σ; MSWD = 17). This age coincides within error with the U-Pb age on zircon from the Fawakhir monzogranite (598 ± 3 Ma). The age coincidence and the hydrothermal Te and Bi metal signature suggest a foremost role of granite-related fluids in the quartz-vein system.

Geologic and Metallogenic Framework of North Africa

“…These intervals are within the Paleoproterozoic (2.5-1.6 Ga), Neoproterozoic (1.6-0.57 Ga), and Paleozoic (570-250 Ma) time spans considered by Goldfarb et al (2001) as being favorable periods for the formation of orogenic gold deposits. (Zoheir et al 2014), which coincides within error of the U-Pb zircon age of 598 ± 3 Ma for the spatially associated monzogranite intrusion (Zoheir et al 2014). These temporal relationships suggest a key role for granite-derived hydrothermal fluids in forming the quartz-vein system.…”

“…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).…”

“…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.…”

The protective role of honey against cytotoxicity of cadmium chloride in mice

“…The association of honey with cyclophosphamide (CPM) ameliorates the evaluated reduced glutathione (GSH), malondialdehyde (MDA) and chromosomal aberrations. Zoheir et al (2015) also stated that honey inhibited the cytotoxic and genotoxic risks associated with the treatment by CPM in mice. Royal jelly has shown a protective effect in opposition to chromosomal abnormalities in bone marrow and histological alterations in kidney produced by valproic acid in male mice (Galaly et al, 2014).…”

Gold-bearing volcanogenic massive sulfides and orogenic-gold deposits in the Nubian Shield

“…The Sukari deposit in the Eastern Desert of Egypt is at the southern end of the major belt of Najd shearing (the "Najd fault corridor") that extends obliquely across, and controls much of, the orogenic gold in the region (Figure 3, inset; Helmy et al, 2004). Other deposits along this belt include El Sid and Fawakhir (Zoheir et al, 2014). Modern mining began at Sukari in 2009.…”