ABSTRACT

In systematic microscopic measurements completed by fission track studies the occurrence of polonium halos and polonium bands could be confirmed in biotites of different areas. The abundance of the different types of polonium halos is given by the order ²¹⁰Po > ²¹⁸Po > ²¹⁴Po. As magmatic and often also hydrothermal mechanisms are contrary to geological evidences a supergene hypothesis has been supposed for the genesis of the polonium halos. According to this mechanism polonium isotopes are accumulated out of uranium or radium-bearing solutions which are liberated from rocks by leaching processes of percolating weathering waters. The concept of the given origin of polonium halos may be significant in discussing problems of dating, uranium prospection and the origin of secondary uranium deposits.