Genesis and mobility of the H2O-CO2 fluid phase during regional greenschist and epidote amphibolite facies metamorphism; a petrological and stable isotope study in the Scottish Dalradian

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doi: 10.1144/gsjgs.140.4.0577
Authors:Graham, Colin M.; Greig, Kenneth M.; Sheppard, Simon M. F.; Turi, Bruno
Author Affiliations:Primary:
Edinburgh Univ., Dep. Geol., Edinburgh EH9 3JW, United Kingdom
Univ. Roma, Italy
Volume Title:Fluids in metamorphism
Volume Authors:Brown, Michael, convener; Powell, Roger; Yardley, Bruce W. D.
Source:Journal of the Geological Society of London, 140(4), p.577-599; Fluids in metamorphism; Geological Societies of the British Isles; fifth meeting, Glasgow, United Kingdom, Sept. 23, 1982, convened by Michael Brown, Roger Powell and Bruce W. D. Yardley. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0016-7649
Publication Date:1983
Note:In English. 2 p. refs.; illus. incl. table
Summary:During high-P, low-T metamorphism in the SW Scottish Highlands, mineral assemblages in metamorphosed basic rocks and calcareous metasediments were controlled by infiltration of hydrous fluids. Three such fluid infiltration events are recognized. During prograde greenschist facies metamorphism, metabasic sills were infiltrated by large volumes of CO2-bearing hydrous fluid (the CO2 being locally derived by widespread oxidation of graphite or other organic carbon in adjacent metasediments). In the epidote-amphibolte facies (garnet zone), dehydration reactions in metabasic rocks generated large quantities of water, which removed carbonate from the metabasic rocks on a regional scale and infiltrated calcareous metasediments to produce grossular-diopside-K-feldspar-amphibole-clinozoisite-sphene assemblages. A late retrograde infiltration of CO2-bearing hydrous fluid under lower-greenschist facies conditions generated K-feldspar + chlorite + rutile + or - dolomite in calcareous rocks and albite porphyroblast schists in zones of intense secondary deformation. Large-scale infiltration of fluid into greenschist-facies metadolerite sills was closely related to, and possibly controlled by, penetrative deformation; in the absence of such penetrative deformation, grain-boundary diffusion was itself an ineffectual mechanism of fluid transport. [R.A.H.]
Subjects:C-13/C-12; Carbon; Carbon dioxide; Dalradian; Epidote-amphibolite facies; Facies; Fluid phase; Geochemistry; Greenschist facies; Isotopes; Lower Ordovician; Metamorphic rocks; Metamorphism; O-18/O-16; Ordovician; Oxygen; P-T conditions; Paleozoic; Petrology; Regional metamorphism; Stable isotopes; Europe; Great Britain; Northern Highlands; Scotland; United Kingdom; Western Europe; Knapdale
Abstract Numbers:84M/0630
Record ID:1985080235
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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