this study was carried out to investigate the effect of crown canopy of ziziphus spina-christi on seed bank characteristics (density and similarity with above ground flora) in two sites with saline-alkaline and alkaline soils. in each soil, forty plots were established, half in and half outside of z. spina-christi cover. in each plot, soil sampling was done from 0-5 and 5-10 cm depths. paired a...

Phillipsite has formecl from volcanic glass in saline, alkaline lakes both saturated and undersaturated with respect to gaylussite and trona. It has also formed from volcanic glass in saiine, alkaline soils of Olduvai Gorge, Tanganyika. Phillipsite occurs both as lath,shaped and as equant crystals, which are commonly zoned lvith refractive indices ranging between 1.438 and 1.490. Molecular SiOz...