THE MORPHOLOGICAL FEATURES OF MICA AND CHLORITE MINERALS IN FINE SAND FRACTION IN SOME FOREST SOILS IN SULAYMANIYAH GOVERNORATE, KURDISTAN
This study was conducted to investigate the morphological features of mica and chlorite minerals in fine sand fraction in some forest soils. Soil profiles were taken from seven different sites of forest soils. Which include Khalakan-Pine, Dukan-Oak, Bakhy-bakhteyare-Pine, Goizha-Cypress and Goizha-Olive. Near each above sites, a reference site of soil was dug and they had the same above properties, but are abandoned soils. Soil samples were analyzed for some physical, chemical and mineralogical properties in the soils. The following results were obtained and can be summarized as follows: Results of chemical analysis were exhibited that the pH values for studied soils were ranged between moderate slightly acidic to alkali (6.62-8.36). The results of electrical conductivity (EC) indicated that all studied soils were non-saline, and the value ranged between (0.13- 2.07 dS.m-1). Amount of calcium carbonate equivalent indicated that the studied soils were calcareous to extremely calcareous soils and the amounts of total and active CaCO3 were ranged between (50-495 g.kg-1) and (10-225 g.kg-1) respectively. As well as the results showed a decrease in content of organic matters with depth in all studied soils. The results of four forms of K in soils: soluble, exchangeable, Non-exchangeable, and mineral were (0.0014-0.0595), (0.40–1.51), (0.02–1.66), and (17.83–38.72) Cmol kg-1 respectively. The change in morphological features of fine sand fraction due to weathering by using optical microscope was investigated and the results showed that the grains of these minerals from individual soil horizons had different colors, those from the surface horizons were have a dark brownish spots, presumable due to staining by organic matter, those from (B) horizon have a yellowish grey-to yellowish brown spots, and those from the (C) horizon were sometimes grey, similar to the parent rocks. In general, almost the grains of chlorite were kept up their green color with depth in all studied pedons, while the surface of these grains in top soil were stained by dark brownish to dark spots, due to partial oxidation of chlorite minerals at the surface soil horizons. The optical microscope examination indicated that mica grains generally occurred as thick particles with different stages of layer separation. They were weathered with layer separations and bending at their edges. However, in control pedons, weak layer separation at the edge was observed.