Polymetamorphic evolution of pelites inferred from tourmaline zoning – the Rędziny hornfels case study at the eastern contact of the Karkonosze Granite, Sudetes, Poland

Abstract

Tourmaline occurring in hornfelses from the eastern envelope of the Karkonosze Granite (Western Sudetes, Poland) reveals at least two stages of crystallization expressed by its complex zoning. The cores and mantles of the crystals probably grew during prograde metamorphism under intermediate pressure-temperature conditions reflected by increasing Mg, Ti and Ca. Outermost rims show enrichment in Al and Ca, indicating growth during contact metamorphism in the presence of an Al-saturating phase. The Ti-content in biotite indicates that the temperature of the contact metamorphic event did not exceed 650ºC. The presence of andalusite and the lack of garnet and cordierite also indicates pressure conditions of ~ 2-3 kbar, typical of the C1 bathozone of Carmichael (1978) or the P1 bathozone of Pattison (2001).

Tourmalines as a Tool in Provenance Studies of Terrigenous Material in Extra-Carpathian Albian (Uppermost Lower Cretaceous) Sands of Miechów Synclinorium, Southern Poland

“…Tourmaline in metamorphic rocks crystallize over a wide range from low-grade to ultrahigh-pressure facies conditions, even above 4 GPa [36,47,48]. The tourmaline often occur in metamorphic rocks such as meta-evaporites [49,50], hornfels [51], aluminous schists [52][53][54][55], gneisses [56][57][58], skarns [59] and marbles [60]. Tourmaline can also be found in sedimentary rocks, where it crystallizes in pore spaces during diagenesis [61][62][63].…”