Yaser M. Abdel-Aziz's research while affiliated with Assiut University and other places

... Dilek et al., 2008;Hajialioghli et al., 2007;Niu et al., 1997). In order to constrain on tectonic setting of the primary rocks of the Salmas serpentinized peridotites, composition of Cr-spinel is used, which is applicable to determine the petrogenesis of ultramafic rocks and peridotites (Ahmed et al., 2005;Oh et al., 2010) and to estimate the partial melting rates (Arai, 1994;Dick and Bullen, 1984;Michael and Bonatti, 1985). Because of modification of Cr-spinel rims by late hydrothermal fluids, only the core compositions of unaltered crystals are used in this regard. ...

... Zincian spinels (gahnite) and silicates (staurolite, garnet) reported from the metamorphosed copper-lead-zinc deposits of different parts of the world mostly formed by desulphidation of sphalerite or direct crystallisation from hydrothermal fluids (Dill 2010, Ghosh et al. 2011Dill et al. 2021. Nevertheless, the possible genesis of zincian chromite different theories are proposed, i.e., primary magmatic (inclusions in diamonds and silicates) and post magmatic (alteration due to metamorphism or hydrothermal fluids rich in Zn content) (Paktunc and Cabri 1995;Gaetani and Grove 1997;Righter 2003;Downes et al. 2004;Gahlan et al. 2006;Gahlan and Arai 2007;Yang et al. 2007;Lagos et al. 2008;Arai and Ishimaru 2011;Fanlo et al. 2015). The primary magmatic zincian chromite is present as inclusions in a diamond within kimberlites and lamprophyres and also as small inclusions in silicate within meteorites (especially iron meteorites). ...

... The relatively high Cr# spinels (0.6 -0.9) of concordant chromitites of the Neoproterozoic ophiolites is not compatible with their formation from a MOR-like melt, which would produce low to intermediate Cr# spinels and PGE-poor chromitites. This could be due to the old age of these Pan-African Late Proterozoic ophiolite complexes, where the thermal state and degree of partial melting of the mantle could be high enough to produce Cr# of Cr-spinels much higher than those of the Phanerozoic ophiolites (Fig. 11b) (Ahmed et al., 2009;Farahat et al., 2011;Ahmed, 2013;Ahmed and Habtoor, 2015;Khedr and Arai, 2016;Arai and Ahmed, 2018). The chromitites from the Phanerozoic ophiolites usually show a wide range in Cr-spinel composition, Cr# varies from 0.3 to 0.9 (compiled by Arai, 1997) (Fig. 11b), possibly depending on the tectonic setting of their formation. ...