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Petrographic relations and uranium distribution in the Skaloti granitoid complex, Paranestion district, Greek Macedonia

Journal Article · · Econ. Geol.; (United States)

The Skaloti granitoid complex consists, for the most part, of biotite granites. The granites are composed of quartz, K-feldspar (mainly microcline), plagioclase, and biotite, with less common muscovite and rare hornblende. Common accessories are allanite, apatite, sphene, epidote, monazite, and garnet. The complex is divided on the basis of texture into two groups-granular and foliated--which have distinct accessory mineralogy. Epidote and sphene coexisting with biotite are relatively abundant in the foliated types; garnet is found only in the granular types. The granular granitoid group includes a leucocratic facies that occurs along the central part of the granitoid terrain. The leucocratic rocks show alteration and mechanical deformation and consist of quartz, feldspar, minor amounts of mica, garnet, and disseminated sulfides (pyrite, chalcopyrite). Sulfide mineralization and hematitization are associated with the microfractures. The alkali enrichment, potassium affinity, moderate to high thorium contents, and presence of uranium-bearing accessory minerals render the complex a possible uranium source rock. The two groups of granitoids (granular, foliated) identified in Skaloti differ in the crystal chemical character of the uranium that they contain. In the foliated granites, the accessory minerals contain most of the uranium and represent refractory uranium sites. Granular granites, on the other hand, contain relatively high soluble uranium; these uranium sites in which uranium is not firmly chemically bound, are related to fragmentation and hydrothermal alteration undergone by the leucocratic granites, and to deuteric and low-temperature alteration which, overall, has affected the rocks of this group. The total uranium contents (U/TAU/) of the analyzed surface samples range between 1 and 39 ppm.

Research Organization:
Geological Laboratory, University of Patras, Patras, Greece
OSTI ID:
6012747
Journal Information:
Econ. Geol.; (United States), Journal Name: Econ. Geol.; (United States) Vol. 77:8; ISSN ECGLA
Country of Publication:
United States
Language:
English