Rich area’s sub volcanic bodies in southwest of Birjand have intruded into Upper Cretaceous ophiolite mélange.  These rocks are in diorite porphyry to monzonite porphyry range and their main texture is porphyry with microgranular groudmass. Plagioclase and green hornblende phenocrysts are made about 70% of these rocks. Plagioclases are andesine with albitic and carlsbad twining and distinct zoning   which altered to calcium carbonate in centeral parts.  Hornblende phenocrysts have altered partly to biotite so show a weakly potassic alteration. The average ratio of Ce/Yb in these rocks are 25.40 and shows they belong to enrich magmatic arc. There is a negative anomaly in high field strength elements (HFSE) such as P, Nb and Ti in these rocks which is a geochemical charactestic of continental margin magmatic arc. High ratio of LREE / HREE, Sr/Y (average is 38.14(, and the amount of SiO₂ with the absent of Eu negative anomaly show that these rocks are very similar to high SiO₂ adakites. High ratio of Sr/Y can be interpreted as high depth melting in plagioclase unstability and garnet stability field. The source of this magma can be an eclogite or garnet amphibolites which is derived from subducted metamorphosed oceanic plate in east of Iran. Dating with zircon uranium – lead show that this magmatic event occurred about 39.1 ± 0.7 Ma (Late Eocene).

Uranium becomes soluble and mobile under oxidizing conditions in aqueous environment, and presence of complexing agents with uranium increase this mobility. Existence of such conditions in groundwaters of Ayrakan and Cheshmeh Shotori areas has led to oxidation, solubility and mobility of uranium minerals. Hydrogeochemical study of uranium in the study areas reveals the presence of bicarbonate ion, as the complexing agent with uranium (UO₂ (CO₃)₂^2-) and icreasing factor of uranium mobility in groundwaters. Calculating the uranium mineral’s saturation index also indicates the super saturation of water samples in pitchblende. The positive saturation index of pitchblende expresses the proper water flow rate to steady-state equilibrium with probable uranium mineralization in depth and indicates that the permeability of groundwaters by porous flow has provided the enough time for their contact with hidden uranium mineralization (uranium ore deposit). As a result of this contact and because of the presence of carbonate complexes, solubility and mobility of uranium has increased. Hydrogeochemical studies, high activity of water and soil samples and all the above evidences indicate the possibility of existence of hidden uranium mineralization in depth and the distance between Ayrakan and the Cheshmeh Shotori areas.