rganic matter and clay miner0 als in soils have negatively charged surfaces that act much like cation exchange resins. When more than 15% of the exchange sites are neutralized by Na+ and the final ionic strength of the aqueous extract is less than about 0.04 M, the clays and organic matter are dispersed. Under these conditions, the solution pH is usually greater than 8.4, and carbonate (COi-) a...

A field experiment was carried out to study the changes of soil bacteria, fungi and actinomycetes in saline-sodic soils for different numbers of cultivated years under drip irrigation. The drip irrigation had substantial effects on levels of bacteria, fungi and actinomycetes. With increased number of cultivated years under drip irrigation, the soil biological properties were greatly improved. A...

Geophysical imaging provides a unique perspective on metasomatism, because it allows the present day fluid distribution in the Earth’s crust and upper mantle to be mapped. This is in contrast to geological studies that investigate midcrustal rocks have been exhumed and fluids associated with metasomatism are absent. The primary geophysical methods that can be used are (a) electromagnetic method...

The area of Esfordi-Zarigan in Central Iran is located in Bafq metallogenic province where most the rock units belong to Precambrian, Infracambrian and Cambrian periods. Although the sedimentary and volcanic rocks are widely distributed, this research is mainly focused on petrogenesis of plutonic rocks. From stratigraphic point of view sedimentary and volcanic rocks can be classified in five ma...

Our aim in this work is (1) to characterize mineralogically and geochemically the brown amphibole and other minerals filling millimetric veins in the Cóbdar metabasalts of the Betic ophiolites in southern Spain, and (2) to deduce their genetic conditions, mainly with the aid of the optical microscopy and analytical electron-microprobe analysis, complemented by transmission and analytical electr...

soil samples from the jakara irrigation project site were evaluated with respect to possible degradation caused by irrigation. most of the soils were neutral to alkaline with ph values ranging between 6.58 + 0.04 and 10.45 + 0.03. the electrical conductivity ranged from 0.3 + 0.01 to 75.2 + 0.06 dsm-1 which implies low to very high salinity. the concentrations of the exchangeable cations in the...

Modern plate tectonic brings down oceanic crust along subduction zones where it either dehydrates or melts. Those hydrous fluids or melts migrate into the overlying mantle wedge trigerring its melting which produces arc magmas and thus additional continental crust. Nowadays, melting seems to be restricted to cases of young (< 50 Ma) subducted plates. Slab melts are silicic and strongly sodic (t...