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CO/sub 2/-rich fluid inclusions from fluid absent granulites, Adirondack Mountains, N. Y

Conference · · Geol. Soc. Am., Abstr. Programs; (United States)
OSTI ID:6460441

Examination of 5 to 20 micron diameter fluid inclusions in low fO/sub 2/ charnockites from the Adirondack Mountains, N.Y. indicate the presence of numerous generations of fluids, including: 1) H/sub 2/O rich 2) three phase (H/sub 2/O liquid and CO/sub 2/ liquid + vapor), and 3) high density, CO/sub 2/-rich. These inclusions are in samples in which the temperature and oxygen fugacity have been determined from coexisting magnetite and ilmenite (Bohlen and Essene, 1977). Fluid calculations in the C-O-H system place limits on the fugacity of CO/sub 2/ in these rocks. A table summarizes results from the most dense CO/sub 2/-rich inclusions in these samples: included are the homogenization temperature (T/sub H/), the melting temperature (T/sub M/), the pressure derived from the CO/sub 2/ density at the peak metamorphic temperature (F/sub FI/), the metamorphic temperature (T) and pressure (P), fO/sub 2/, and XCO/sub 2/ from C-O-H calculations. Many of these samples are orthopyroxene + K-feldspar bearing indicating reduced H/sub 2/O activities. Low CO/sub 2/ + H/sub 2/O in samples such as IN-10 and SR-31 indicates vapor absence. The presence of CO/sub 2/-rich fluid inclusions have been interpreted as indicating that the peak of granulite facies metamorphism is dominated by and possibly caused by CO/sub 2/-rich fluids. The authors results suggest that high density CO/sub 2/-rich fluid inclusions do not, in at least some cases, represent the primary metamorphic fluid.

Research Organization:
Univ. of Wisconsin, Madison (USA)
OSTI ID:
6460441
Report Number(s):
CONF-8510489-
Journal Information:
Geol. Soc. Am., Abstr. Programs; (United States), Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Vol. 17; ISSN GAAPB
Country of Publication:
United States
Language:
English