Oliwiny ze skał ultramaficznych masywu Jordanów–Gogołów (ofiolit sudecki)— zapis zróżnicowanych procesów geologicznych

Abstract

Olivines from ultramafic rocks of Jordanów-Gogołów Serpentinite Massif (Sudetic ophiolite) — a complex interplay of petrogenetic processes.A b s t r a c t . Olivines occurring in the Jordanów-Gogołów Serpentinite Massif (JGSM) in the Polish Sudetes were formed during complex series of geological events and processes: growth in the upper mantle; crystallization of ultramafic cumulates at a mid-ocean ridge; ultra-high pressure (UHP) and high pressure metamorphism in a subduction zone; and contact metamorphism related to intrusion of boninitic and/or granitic magmas into the JGSM. The presence of olivine with pseudocleavage and intergrowths of ferrichromite and of pseudospinifex olivine indicates very fast transport from UHP conditions (from depths ca. 410 km) to the surface, similar to the model proposed by Brueckner & van Roermund (2004). The range of metamorphic conditions (from UHP to zeolite facies) recorded by JGSM olivines and also by associated serpentinites indicates that the JGSM is a fragment of an accretionary prism.