Minerały ciężkie w utworach trzeciorzędowych czwartorzędowych zagłębia żytawskiego

Abstract

HEAVY MINERALS IN THE TERTIARY AND QUATERNARY FORMATIONS OF THE ŻYTAWA BASINSummaryThe Żytawa basin is filled in with the Miocene formations represented mainly by shallow-water fluviatile and ice-marginal lake deposits, accompanied by brown coal formations. Quaternary deposits consist mainly of Pleistocene fluviatile sediments of the Nysa Łużycka River and of its tributaries. Among them, two gravel – arenaceous horizons may be distinguished, differing in their age and petrographical and mineral composition.Samples of the Miocene and Pleistocene formations were taken for analyses in a period from 1964 to 1966 within the area of the Turów l and Turów II brown coal mines. The samples were subdivided into fractions and then heavy minerals were separated. This allowed the author to ascertain various concentration of minerals in various fractions.The mineral assemblages found in the formations mentioned above differ from each other in having other composition and contents of minerals. The Miocene assemblage proved to be the poorest one, revealing only minerals characterized by highest resistance. In the coarser fractions andalusite predominates, in the finer ones –zircon. In the older Pleistocene formations the assemblage of minerals is, as a rule, similar to that of the Miocene. It differs only by having higher percentage of green hornblende and by high tourmaline and topaz contents. The assemblage of the younger Pleistocene is the richest one. Here prevails clinopyroxene that does not appear in both assemblages mentioned previously. Moreover, there are found also lamprobolites and various species of garnets and tourmalines other than those found to occur in the assemblages discussed above. A high zircon, concentration in the Miocene formations is a result not only of a wide-spread occurrence of this mineral in the adjacent rocks, but also of the elimination of less resistant minerals.