Mineralogical and chemical composition of sand ore deposits in the seashore zone N. Peramos - L. Eleftheron (N. Greece)

Résumé

This study concerns the U-Th ore deposits containing also Ti and R.E.E., located at the area between Nea Peramos and Loutra Eleftheron, of the Kavala prefecture, North Greece, in the contemporaneous littoral zone. From this littoral zone of 25 Km. total length and 50 m. average width, were collected 142 samples of shoreside surficial sand and 128 specimens from depths up to 2 meters. In the contemporaneous littoral zone very high surficial levels of Uranium were found, (with an average value of 22 ppm U and a highest value of 92 ppm U), as a result of today's and mainly older sea wave-action, at the lower parts of the sandy shoreside formations, and with the highest expected enrichment in the bedrock cavities. Initial samples of U enriched sands (up to 50 ppm) are considered to be a naturally grated multimetal ore of Ti, U-Th, R.E.E.,.Au and other metals for high-value technological applications. The concentrations of the above metals are higher of those known to other similar ores (2.5%, 50-1600 ppm, 11.000 ppm and 250 mg/m3 respectively) and can be multiplied with a light water-metallurgical processes. In the present shoreside zone, lower layers of sands formed out with the processus of natural grate action, are mainly the medium grain sands and secondarily the fine grain variety. These natural enrichments due to sea wave-action, form selective concentrations of U and R.E.E. enriched allanite, which are responsible for the content in metals of high-value technological applications. On the contrary, the coexisting minerals of titanite, zircon, apatite, and epidote, as well as the iron minerals, do not much contribute in the increment of this content.