Composition of tourmalines from tin-tungsten-bearing country rock of the Variscan Karkonosze granitoid - a record of the wall rock and hydrothermal fluid interaction
Słaby, Ewa; Kozłowski, Andrzej
published: Jun 9, 2005
ArtNo. ESP154018103004, Price: 29.00 €
Tourmaline, a product of interaction of B F-rich fluids mobilized by granite pluton with country rocks embedding the pluton has been investigated. The country rock alteration yielded albite metasomatites, greisenised granite-gneisses and greisens. The rocks bear tin-tungsten mineralization of no economic significance. They form a sequence, in which each one of them is a link in continuous, progressive alteration process, finally leading to greisen formation. The path of the process was reconstructed by means of consideration of the tourmaline composition and fluid inclusion study results. The tourmaline crystallized in two stages, resulting in formation of a dravitic core (preceding greisenization) and a schorl-enriched outer zone (formed simultaneously with greisenization). The composition of the outer zone of tourmaline grains reflects the fluid evolution. It changes along the ongoing process and seems to be good indicator of the evolution of the wall rock alteration.