Textures, involving grain sizes, grain shapes, grain orientations, and grain inter-relations, are difficult to quantify, but the human brain is an excellent patternrecognition machine, and we can commonly determine at a glance whether one texture is a good match for another, particularly in the matter of grain size, modal proportions of felsic and ferromagnesian
minerals, and grain orientations.
05), is attributed to the higher proportion of ferromagnesian
minerals, derived from mafic and ultramafic rocks.
It has been suggested that variations in MS are related to changes in lithogenic (aqueous, detrital and aeolian) inputs during transgressive-regressive cycles, which in turn results in changes in the amount of iron, clay and ferromagnesian
A general equation for estimating Fe3+ concentrations in ferromagnesian
silicates and oxides from microprobe analyses, using stoichiometric criteria.
The depleted content of Fe and Mn in this groundwater is attributed to the poverty of ferromagnesian
minerals in the water bearing sediments in the desert areas of Nile valley (Omer 2003; Gomaa 2006).
On the other hand, depletion of Mg and Mn from the system is related to decomposition of ferromagnesian
This correlation can be due to similar geochemical behavior of these elements, such that these elements can be in the early stages of magmatic differentiation replacement of each other in a structure of ferromagnesian
minerals of ultramafic rocks .
Several trace elements occur preferentially in ferromagnesian
1987): A general equation for estimating Fe3+ concentrations in ferromagnesian
silicates and oxides from microprobe.
Biotite is a common hydrated ferromagnesian
silicate in most mafic, intermediate and felsic plutonic rocks which related to Mn metal species and confirmed by another g signal which appear at a lower magnetic field 3700 G.
However, in the study area, the sources of the iron and manganese can be attributed to weathering of iron and manganese bearing minerals and rocks, such as amphiboles, ferromagnesian
micas and magnetite.
The texture of andesite is generally porphyritic, with phenocrysts of feldspar and ferromagnesian