Abu Zarab locality is a part from Um Bogma area in southwestern Sinai, Egypt, where paleokarsts are widespread, especially in carbonate rocks. Abu Zarab area is covered by Carboniferous carbonate rocks containing several paleokarsts. One of these paleokarsts was selected to geochemical investigation. The paleokarst was dissected by three excavated trenches constructed by Nuclear Materials Authority team to reveal its geologic features. The paleokarst is filled with lateritic components represented mainly, by gibbsite, ferruginous siltstone and clay minerals.

Twelve samples were collected from the walls of these trenches and chemically analyzed for this purpose in term of major oxides, traces and rare earth elements. The geochemical data of the major oxides display three important geochemical processes in the lateritic components of the paleokarst: (1) Enrichment of aluminum, iron and manganese; (2) depletion of calcium and magnesium (3) silicon experienced both depletion and enrichment. The geochemical data of trace and rare earth elements (REE) display enrichment of U, Cu, Pb, Zn, Ag, As and Cd with obvious enrichment of REE and conversely some elements were depleted such as V, Cr and Ga. It also, noticed that uranium has strong positive correlation with both iron and Aluminum.

This paper attempts to establish the relation between uranium and other elements in the paleokarst conditions. It is more likely, according to geochemical features of radioactive elements, that the uranium enrichment process was postdating laterite formation and the iron played an important role in capturing and trapping uranium.