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Stable isotope evidence for limited fluid infiltration of deep crustal rocks from the Ivrea Zone, Italy

Journal Article · · Geology; (United States)
Isotopic and petrologic studies of the Ivrea Zone, a segment of deep-crustal high-grade rocks, suggest that metamorphism did not involve the transfer of large quantities of CO/sub 2/ from mantle to crust. High-grade Ivrea Zone calcites may retain high ..delta../sup 18/O (up to 24 per thousand SMOW), indicating little interaction with externally derived fluid. Graphite isotopic compositions (..delta../sup 13/C = -10 per thousand to -25 per thousand PDB) that do not vary with grade are attributed to mixing between carbonate carbon and biogenic noncarbonate carbon. Calcites from high-grade, carbonate-poor amphibolites have ..delta../sup 13/C of about 1 per thousand PDB and sedimentary, not infiltrative, origins. The general lack of carbon and oxygen isotopic homogenization suggests that fluid interactions may be explained in terms of fluid generated internally to the Ivrea Zone metasedimentary rocks.
Research Organization:
Grant Institute of Geology, Edinburgh (Scotland)
OSTI ID:
7042403
Journal Information:
Geology; (United States), Journal Name: Geology; (United States) Vol. 16:6; ISSN GLGYB
Country of Publication:
United States
Language:
English