Minerały z rozsypisk chromitowych w okolicy Uliczna na Dolnym Śląsku

Abstract

MINERALS FROM CHROMITE PLACERS IN THE ULICZNO REGION, LOWER SILESIA

Summary

Heavy minerals that have been identified in heavy concentrates from the chromite placers in the region of Uliczno, Lower Silesia, can be divided into three genetical groups:

1 – minerals related to the decomposition of ultrabasic rocks of the massif and possible endogenous ore concentrations in these rocks: chromirtes, magnetite, ilmenite, hematite, garnets of pyrope group, nickel talc, and most probably colerainite;

2 – minerals typical of veins and dikes related to granitoid magmatism: zircon,

gold, pyrite, which as a rule occur along with quartz and feldspars;

3 – minerals from crystalline schists land gneisses of the Sowie Mts. massif:

disthene and garnets (almandine).

Siderite that occurs at some places represents a mineral most probably formed tinder hypergenic conditions.

X-ray examinations of chromites allowed the authors to distinguish, the placers of the region of Uliczno and in the Tąpadła deposit, the following minerals: aluminium chromites, with varying parameters of unit cells, according Cr₂O₃, and chrompicotite. The Cr₂O₃ content, determined in these chromites by means of X-ray spectrograph, ranges from 30 to 45%, thus it can be practically used only in production of refractories, and in chemical industry. A possibility exists to discover new endogenous ore bodies in the region in study, as proved by both the high concentration of chromites in the placers and their similarity to those found in the mine Tąpadla, situated on the other of the watershed.