The character and evolution of hydrothermal fluids associated with the kaolinized St. Austell Granite, SW England

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doi: 10.1144/gsjgs.140.2.0297
Authors:Alderton, D. H. M.; Rankin, A. H.
Author Affiliations:Primary:
Chelsea Coll., London SW10 0UA, United Kingdom
Imperial Coll., United Kingdom
Volume Title:Journal of the Geological Society of London
Source:Journal of the Geological Society of London, 140(2), p.297-309. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649
Publication Date:1983
Note:In English. 21 refs.
Summary:A complex assemblage of fluid inclusions is found in quartz from the St Austell granite; homogenization T range from <100° to >570°C with salinities ranging <1 to 42 wt.% NaCl equivalents. Regional variations in the abundance and type of the inclusions can be correlated with the petrology of the host rock; low-T, low- salinity fluids are most abundant in extensively kaolinized granite and represent the latest phase of fluid activity and were probably responsible for the China clay deposits, at T 150°-<70°C. The most saline fluids are restricted to the lithionite and fluorite granites. They could represent either the earliest fluids associated with these granites or the concentrated residue formed by boiling of an earlier, more dilute fluid. In the biotite granite, the earliest fluids have salinities of approx 10-20 wt.% NaCl equivalents, and it can be shown that these fluids boiled at approx 520°C. Abundant gas-rich inclusions in all rock types show that episodic boiling did occur during the evolution of the hydrothermal phase. [R.A.H.]
Subjects:Chlorides; Fluid inclusions; Geochemistry; Granites; Halides; Halite; Hydrothermal conditions; Igneous rocks; Inclusions; Kaolinization; Metasomatism; Petrology; Phase equilibria; Plutonic rocks; Processes; Salinity; Temperature; Cornwall England; England; Europe; Great Britain; South-West England; United Kingdom; Western Europe; Saint Austell Granite; Southwestern England
Abstract Numbers:83M/2666
Record ID:1985060238
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom, Reference includes data from PASCAL, Institute de l'Information Scientifique et Technique
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