Geology, Petrography, and Mineral Chemistry of the Zn Pb-Cu-Sulfide Deposits of the Filfila Massif (East Algeria)

Abstract

The Filfila Massif consists of four stacked tectonic units, which are superimposed on a metamorphic basement. The Filfila metasomatic-type polymetalic deposit of the Northeast crosscut the tectonic units of the Filfila and the proximal granites. The deposits consists of lead and zinc mineralization associated with iron oxides, hydroxide and accessory minerals. To highlight the mineralogical, petrographical and geochemical characteristics of the deposit, several methods have been combined: Microscopic observation, XRD diffractometry, XRF spectrometry, scanning electron microscopy with energy-dispersive X-ray spectrometry (SEMEDS) and fluid inclusion microthermometry. Field observations and Analyses indicate that the orebody in Filfila displays a complex geometry. The shows are located in the limits of the thrust sheet structure within the metamorphic basement that plunges eastward at about 20°–30°. The veins range between 60 m and 1000 m lengths and from 10 cm up to 3 m in the thickness. The strikes follow the same directional trend (E-W) as the Filfila granites, and are steeply dipping 60°–80°. Ore minerals include quartz, fluorite, barite, galena, sphalerite, cupper sulfides, sulfosalts and oxides. The deposit turns out to be closely associated with to the Miocen post-orogenic Filfila granite.