| چکیده انگلیسی مقاله |
Depositional cessations during Permian period in north of Saqqez were associated with development of lenses of bauxite-kaolin ores in Ruteh carbonate formation. In one of these lenses considered, six lithologic units were recognized which are from bottom to the top, (1) dark brown red, (2) violet, (3) multicolor, (4) pink (5) yellow, and (6) white (kaolin). Calculations of absolute weathering index for these units indicate that elements such as Si, Na, K, P, Mn, Mg, Ca, Sr, Ba, and Lu were leached during the weathering processes from basaltic rocks and elements such as Th, U, Y, Nb, Hf, Zr, Tb, Dy, Ho, Er, Tm, and Yb enriched. Whereas, elements such as Al, Fe, Ti, Rb, V, Cr, Ni, Co, La, Ce, Pr, Nd, Sm, Eu, and Gd have born leaching-fixation processes during the development of the weathered profile. The obtained results show that processes such as adsorption, scavenging and concentration by Fe-oxides and hydroxides, stability of metal-carrying complexes, variations in chemistry of weathering solutions, the presence of organic matters, fixation in neomorph phases, and the presence in the resistant mineral phases were the important factors that have played pronounced roles in distribution of elements in these deposits. |