Mineralizacja agatowa w wulkanitach czerwonego spągowca w rejonie Nowego Kościoła (Góry Kaczawskie)

Abstract

AGATE MINERALIZATION IN ROTLIEGENDES VOLCANIC ROCKS IN THE VICINITIES OF NOWY KOŚCIÓŁ (GÓRY KACZAWSKIE MTS) Summary The geological setting of agate mineralization in Rotliegendes volcanic rocks in the vicinities of Nowy Kościół is discussed. Two forms of mineralization were found: 1) agate-bearing nodules in weathering cover of volcanic rocks and 2) chalcedony veins in compact rhyolites. The distribution of mineralization is given along with descriptions of localities and petrographic characteristics of exposed rocks. The map (Fig. 1) and sketch cross-section (Fig. 2) show the extent of mineralization. It was found that agate-bearing nodules occur in a characteristic weathering cover developed in top parts of tuffs, beneath the major cover of rhyolite lava. It is assumed that the origin of agates has been primarily determined by decay of acid volcanogenic rocks of the tuffolava type under the influence of volatile components and volcanic solution. This process could result in secretion of silica in the form of chalcedony (or, perhaps, at first opal) as well as in origin of the characteristic weathering cover with agate-bearing nodules.