Mineral genesis and radioactivity of the upper part of the Adediya Formation, southwestern Sinai, Egypt

- The upper part of the Adediya Formation (Cambro-Ordivician) exposed in southwestern Sinai.
- It contains mineralizations which are exceptionally rich in radioactive and rare earth elements as well as heavy metals.
- The recorded mineral assemblage consists of a large number of essential and accessory minerals some of which are radioactive and REE-bearing.
- The obtained field and laboratory data were implemented to determine the sedimentary history of the host rocks.

The upper part of the Adediya Formation (Cambro-Ordivician) exposed in southwestern Sinai represents a very interesting succession. It contains mineralizations which are exceptionally rich in radioactive and rare earth elements as well as heavy metals. Field and several laboratory studies were carried out on this part of the Adediya Formation exposed in four stratigraphic sections distributed in a geographically wide area in southwestern Sinai.The radioactive mineralizations exist in sandstones, ironstone bodies and, to a much lesser extent, siltstones. Each of these rock types has a relatively wide range of textural characteristics. The recorded mineral assemblage consists of a large number of essential and accessory minerals some of which are radioactive and REE-bearing.The obtained field and laboratory data were implemented to determine the sedimentary history of the host rocks and the genesis of the mineral species which constitute the mineralizations. This included the identification of the types and effects of the various diagenetic processes and hydrothermal activity which led to the genesis of the recorded mineralizations. Also, the relative roles played by these post-depositional processes in determining the mineral, chemical and radioactive characteristics of the mineralizations and host rocks were assessed. These roles resulted in redistribution of the various elements especially the radioactive and rare earth elements as well as heavy metals during the epigenetic phase particularly by the action of supergene processes. A genetic model for the studied mineralizations is proposed.