The mineralogy of Egyptian serpentinites and talc-earbonates

Abstract

SummaryOptical, d.t.a., X-ray, and chemical analysis investigations were carried out on serpenttinites from various Egyptian localities and on their associated talc-carbonates. The serpentinites were proved to consist of pure antigorite, lizardite, or clinochrysotile, or of mixtures of any pair of these serpentine minerals. Lizardite, which is reported for the first time in Egypt, is found to be of common occurrence. Talc, tremolite, carbonates, chlorite, olivine, biotite, chromite, magnetite, goethite, and stevensite are the main admixtures. The talc-carbonates consist mainly of talc and magnesite, or magnesite, dolomite, and talc together with minor amounts of antigorite, magnetite, goethite, and occasionally a little chlorite or calcite. Spectrographic analyses of some of the magnetically separated serpentines have been carried out and the origin of the Egyptian serpentinites and talc-carbonates is briefly discussed.

Leaching optimization of mining wastes with lizardite and brucite contents for use in indirect mineral carbonation through the pH swing method

“…On the other hand, the lizardite 1T employed by Viti (2010) presented a content of 2.89%, being more stable thermally. Basta and Kader (1969) extensively evaluated the thermal stability for several lizardites with low Al 3þ contents, in the form of Al 2 O 3 (0.28e1.00%), as well as Weber and Greer (1965) and F€ oldv ari (2011). These authors reported a dehydroxilation temperature in the interval of 635 Ce685 C. However, thermal stability of lizardite with high Al 2 O 3 contents (2.39e2.89%), studied by Viti (2010), presented a dehydroxilation temperature in the range of 708 Ce714 C, demonstrating an influence of Al 3þ in the thermal stability of lizardite 1T.…”

Petrological and mineralogical studies of Pan-African serpentinites at Bir Al-Edeid area, central Eastern Desert, Egypt

“…The foliation of the intensively sheared serpentinites is parallel to the schistosity of the surrounding metavolcanic rocks. Along shear zones, the serpentinite bodies are replaced by talc-carbonate rocks due to CO 2 metasomatism (Akaad and El Ramly, 1961;Basta and Abdel Kader, 1969;Basta and Hanafy, 1971;Akaad and Noweir, 1972). Fresh peridotite relics occur as minor bodies within the serpentinite masses, a feature not recorded in the studied area before.…”

Metasomatic zonation of an ultramafic lens at Ikátoq, near Færingehavn, southern West Greenland

“…The main serpentine phasc is lizardite, which occurs as networks comprising blades and plales of interlocking grains; rare chrysotile occurs as clear and fibrous Abdel Kader (1969), McKenzie (1970), Coleman & Keith (1971) and Wicks & Whittaker (1975). Carbonate is synchronous with second-phase chrysotile and is cut by chrysotile veinlets.…”