Geologiczno-geofizyczna ocena perspektyw złożowych pierwotnych i wietrzeniowych minerałów tytanowych w rejonie ofiolitowego masywu Ślęży w Sudetach (SW Polska)

Abstract

Geologic and geophysical estimation of the prospect for ore deposit of the occurrences of primary and placer titanium minerals in the OElê¿a Massif ophiolite, area, the Sudetes Mts (SW Poland).A b s t r a c t. A Miocene aged heavy mineral (HMin) alluvial cones and regolith sands above ore-bearing gabbro and amphibolite/diabase rock zone were considered as a prospective metallotect in the area of Devonian ophiolite Ślęża Massif in the Sudets (SW Poland). The available research data from the Sobótka region indicated that the ultramafic gabbro intrusion has an interesting titanium ore enrichment with minerals such as ilmenite and titanomagnetite in the Strzegomiany-Kunów primary ultramafic rocks. The mean composition of ore gabbro samples taken from the surface contained eg; Fe – 14.21%, TiO2 – 4.92%, V2O5 – 0,15. Conducted geophysical surveys in the vicinity of the presumed gabbroic rocks at thin Quaternary sediments cover, suggested the variable content of a primary mineralization, which could be related to the increased content of heavy minerals fractions over the bed in the form of regolith or as a secondary deposit. Titanium minerals such as ilmenite, sphene, were enriched during the oxidation process and created secondary bed, where the concentrates of titanium oxides: rutile, leucoxene or oxidized ilmenite may have a high titanium content as high as 70–90%. Placer HMin sands are at present a major source of titanium deposits worldwide and the largest industrial value due to their large resources, simplicity and purity of exploitation and the ability to yield concentrates of HMin: ilmenite, rutile, pseudobrookite, anatase and leucoxene, sometimes in the company of valuable zircon, monazite or garnet. These deposits in the world are mainly used in metallurgical and chemical industries, eg; the production of paints and pigmentsused in the pharmacy, paper and paint industry. Similar observations have been reported from the region of Spain, Portugal, western Australia and from the south of India. Preliminary results of presented study indicate that the Strzegomiany–Kunów region can be considered as prospective not only because of the presence of primary titanium mineralization in gabbro, especially in diallage gabbro, amphibolite (diabase) and serpentinite, but also a presence of enriched titanium mineralization in regolith over gabbro and in clasticsediments on the foreland of Ślęża Massif.