Listvenitization of Neoproterozoic ophiolitic serpentinites and formation of gold-bearing listvenites in the Mueilha-Dungash area, Eastern Desert of Egypt, Arabian-Nubian Shield

Abuamarah, Bassam A. , Drueppel, Kirsten , Azer, Mokhles K.

2026-08-01 LITHOS 2026   534(卷), null(期), (null页)

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The ophiolitic sequence exposed in the Mueilha-Dungash area, Egypt represents a fragmented Neoproterozoic ophiolite within the northern Arabian-Nubian Shield. Serpentinites are the dominant lithology and preserve fresh relics of primary minerals such as olivine, orthopyroxene, and Cr-spinel. These serpentinites are extensively altered, giving rise to listvenites, rodingites, talc-carbonate rocks, and magnesite veins. Listvenites, which consist of varying proportions of magnesite and quartz, occur as dyke-like bodies or lenses and are subdivided into carbonate-rich listvenite, quartz-carbonate listvenite, and quartz-rich listvenite (birbirite). The carbonate-rich listvenite formed early, pre-dating obduction but post-dating serpentinization, through infiltration of externally derived CO2-rich fluids. Following obduction, quartz-carbonate listvenite developed through influx of hydrothermal, crustally derived SiO2-rich fluids circulating during ophiolite emplacement. Birbirite represents the latest stage, formed by silicification of pre-existing listvenites. This progressive listvenitization is associated with notable enrichment in precious metals, particularly gold, in the quartz-carbonate samples. The gold content increases in tandem with elevated concentrations of Zn, As, Cu, Ag, and Pb, suggesting a shared source and fluid pathway for these elements.