The effect of gleyzation on iron compounds in red-colored deposits (experimental results)

Red-colored deposits occurring in the northwest and east of the Russian Pla in lose their red color upon gleyzation under a stagnant water regime eithe r because of dissolution of hematite particles or because of their dispersi on and separation from the clay mineral surfaces. In clayey deposits with i ron minerals presented mainly by fine crystals, processes induce the dissol ution of hematite and goethite. Tn sandy deposits, gleyzation contributes t o the dispersion of relatively coarse hematite grains in clay fraction and their separation from the clay mineral surfaces. Gley is more advanced in d eposits with a higher degree of iron oxidogenesis, expressed as the Fe-d/Fe -t ratio.