If you are experiencing problems downloading PDF or HTML fulltext, our helpdesk recommend clearing your browser cache and trying again. If you need help in clearing your cache, please click here . Still need help? Email help@ingentaconnect.com

Halogen contents of eclogite facies fluid inclusions and minerals: Caledonides, western Norway

The full text article is temporarily unavailable.

We apologise for the inconvenience. Please try again later.

Download / Buy Article:

Abstract:

Abstract

Primary multiphase brine fluid inclusions in omphacite and garnet from low- to medium-temperature eclogites have been analysed for Cl, Br, I, F, Li and SO4. Halogen contents and ratios provide information about trapped lower crustal fluids, even though the major element (Na, K, Ca) contents of inclusion fluids have been modified by fluid–mineral interactions and (step-) daughter-crystal formation after trapping. Halogens in the inclusion fluids were analysed with crush–leach techniques. Cl/Br and Cl/I mass ratios of eclogite fluids are in the range 31–395 and 5000–33 000, respectively. Most fluids have a Cl/Br ratio lower than modern seawater and a Cl/I ratio one order of magnitude lower than modern seawater. Fluids with the lowest Cl/Br and highest Cl/I ratios come from an eclogite that formed by hydration of granulite facies rocks, and may indicate that Br and I are fractionated into hydrous minerals. Reconstructions indicate that the inclusion fluids originally contained 500–4000 ppm Br, 1–14 ppm I and 33–438 ppm Li. Electron microprobe analyses of eclogite facies amphibole, biotite, phengite and apatite indicate that F and Cl fractionate most strongly between phengite (F/Cl mass ratio of 1469 ± 1048) and fluid (F/Cl mass ratio of 0.008), and the least between amphibole and fluid. The chemical evolution of Cl and Br in pore fluids during hydration reactions is in many ways analogous to Cl and Br in seawater during evaporation: the Cl/Br ratio remains constant until the aH2O value is sufficiently lowered for Cl to be removed from solution by incorporation into hydrous minerals.

Keywords: dehydration; eclogite; fluid inclusions; halogen fractionation; halogens; hydration

Document Type: Research Article

Affiliations: 1: Department of Geology, University of Oslo, PO Box 1047 Blindern, N-0316 Oslo, Norway 2: School of Earth Sciences, University of Leeds, Leeds, LS2 9JT, UK 3: Mineralogical-Geological Museum, University of Oslo, N-0562 Oslo, Norway

Publication date: February 1, 2001

Related content

Tools

Favourites

Share Content

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial Content
Free trial content
Cookie Policy
X
Cookie Policy
ingentaconnect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more