Geochemical Prospecting at Um Ud Gold Mine Area, Estern Desret, Egypt

S.O.Khalil1, A.I.Arslan1, M.M.El-Sayed2, K.I.Khalil1 and H.M.El-Deeb1

 1-Geology Department, Faculty of Science, Alexandria University,Alexandria, Egypt        2-Dean of Faculty of Science, Damanhour branch, Alexandria University, Egypt.

The shear zone-controlled gold mineralization at Um Ud gold mine is hosted   in Pan-African metavolcanics, metagabbro-diorite rocks as well as tonalite.The mineralized shear zone comprises boudinaged NW trending auriferous quartz veins enveloped by wallrock alteration zones. These veins show some characteristic primary as well as superimposed textures. A generalized style of hydrothermal zones is ascertained. The inner alteration zones proximal to the auriferous quartz veins comprise carbonate, sericite, albite, biotite, quartz and minor chalcopyrite, while the outer zones are dominated by chlorite and epidot. The mass-balance calculations of wallrock alterations are revealed an addition of some elements such as Si, Ca, Mg, Fe, K, Na, and volatiles, Rb, Ba, Sr and Cu dominated by the alteration minerals.

The statistical study of the raw geochemical data includes univariate and multivariate statistical treatment. The frequency distribution of P2O5, TiO2 and some trace elements (Au, Ag, Mo, Cu, Zn, S, Cr, V, Co and Ni) revealed unimodal lognormal distribution. The R-mode factor analysis of the chemical data revealed a five-factor model. The revealed R-mode factor represents the best explanation for geochemical associations in the mineralized veins and the hydrothermally altered wallrocks. The geochemical data are manifested by variation of elements along some profiles as well as geochemical and factor score maps. These maps are found excellent for pointing to the highly mineralized sites of veins and wallrock alterations and the overall zoning model of the Um Ud gold mineralization.

The variation and spatial distribution of Ag/Au ratios in the mineralized veins and contact wallrock alteration zones revealed good indicators for gold-mineralized sites. These ratios are clearly manifesting a distinct model for lateral and vertical zoning of the Um Ud gold mineralization