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Table of Contents


Vol. 9 - 2010

Vol. 8 - 2009

Vol. 7 - 2008
SP 1 - 2008

Vol. 6 - 2007
Vol. 5 - 2006
Vol. 4 - 2005
Vol. 3 - 2004
Vol. 2 - 2003
Vol. 1 - 2001-2002

Notes for Authors
(PDF - 80 kb)



GeoActa Special Publication 1 2008


Acquisto online

GeoActa
an international Journal of Earth Sciences


Roberto Braga and Giovanna T. Sapienza
Dipartimento di Scienze della Terra e Geologico-Ambientali, Universita' di Bologna, Piazza di Porta S. Donato 1, 40126 Bologna, Italy. E-mail: r.braga@unibo.it; giovanna.sapienza@unibo.it

Groundwaters on the island of Salina (Aeolian Archipelago, Italy): geochemical aspects and genetic considerations


Volume 6, 2007, pages 37-45

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Abstract

A dolomite-bearing chlorite-amphibole peridotite from the Ulten Zone (Eastern Alps) preserves the mineralogical and textural record of three metamorphic assemblages: the near-peak condition M1 stage (= garnet-amphibole) and the exhumation-related M2 and M3 stages (= spinel-amphibole and chlorite-amphibole, respectively). This metamorphic evolution supports the hypothesis that chlorite-bearing peridotites from the Ulten Zone represent the retrograde equilibration product of former high-pressure garnet-bearing peridotite. Multi-equilibrium thermobarometry, which involves also hydrous phases, dolomite and a C-O-H fluid phase, gives P ~ 1.8-2.2 GPa, T 800°C (M1) and P ~ 1.5-1.7 GPa, T ~ 730°C (M3). M2 stage lacks minerals suitable for multi-equilibrium computation. During the retrograde evolution, the CO2 content X(CO2) of the fluid phase increased from 0.1 to 0.5.

Keywords: Dolomite-bearing peridotite, multi-equilibrium thermobarometry, average PT method, Ulten Zone