Kasyteryt i inne minerały ciężkie w aluwiach potoku Brusznik

Abstract

CASSITERITE AND OTHER HEAVY MINERALS IN THE ALLUVIAL DEPOSITS OF THE BRUSZNIK STREAMSummaryThe paper presents the results of the investigations made in 1968-1969 on the alluvial deposits in the Brusznik stream, between Leśna and Świecie (Pogórze Izerskie - Sudetes). The Brusznik stream valley is filled in with the Quaternary gravels and sands, from 3 to 7 m in thickness. Detailed mineralogical examinations have been made on schlich samples taken from bore holes K-5, K-21 and K-35, situated along three drilling sections. The association of heavy minerals found to occur in the alluvial deposits of the Brusznik stream consist of ilmenite (from 23 to 31% of schlich volume), cassiterite, iron oxides, topaz and garnets (all from 6 to 14% of schlich volume), as well as of zircon, tourmaline, and rutile (not more than 5% of schlich volume). Moreover, other minerals have been distinguished, too, among them: olivine, augite, staurolite, sillimanite, grammatite, pyrite, scheelite, fluorite, corundum, anatase, disthene and gold. Chemical analyses and mineralogical observations allowed the author to determine preliminarily the association of index minerals that accompany cassiterite in the alluvial deposits of the Brusznik stream. Here belong: topaz, haematite, limonite, zircon, coarse-crystalline rutile (nigrine), tourmaline, fluorite, scheelite and gold. The schlich analysed did not reveal, however, such type index minerals as wolframite lithium minerals, sphalerite and columbite. Four varieties of cassiterite have been distinguished, characterized by different colour, structure and percentage. Each of the varieties has been spactrally analysed and trace elements have been determined. The data obtained are useful in drawing conclusions concerning the genesis of the clastic cassiterite found in the alluvial deposits of the Brusznik stream.