stripes
Intruded into syn- and post-tectonic granites and volcano-sedimentary rocks, Faronge is a 4x5 km complex consisting of a core of gabbro surrounded by a broad, vertical ring of syenite. The gabbros grade from an outer mesocratic hornblende gabbro, containing a 'basaltic hornblende' and phlogopite, to a very coarse melanocratic hornblende gabbro, to a central area of olivine gabbro. The ring-dyke syenite is a coarse rock of perthite, aegirine-augite, amphibole, biotite, chlorite, iron oxides, titanite and apatite. There are numerous, mainly arcuate, dykes around the complex including basaltic, felsitic, trachytic and phonolitic types. The trachytes include aegirine-augite, amphibole and feldspar, which may be spherulitic. Euhedral sodalite crystals are the main phenocryst phase in the phonolites. Some 40 rock analyses, including trace elements, are available.
VAIL, J.R., HUGHES, D.J., ABDEL MAGID, A.E.M., ABDEL RAHMAN, E.M. and TOUM, I.M. 1986. Geology of southern Blue Nile Province, Sudan. Bulletin of the Geology and Mineral Resources Department, Republic of the Sudan, 37: 1-32.
