Published May 1984
| public
Journal Article
Distribution of Ordovician and Devonian metamorphism in mafic and pelitic schists from northern Vermont
- Creators
- Laird, Jo
- Lanphere, Marvin A.
- Albee, Arden L.
Abstract
^(40)Ar/^(39) Ar range from 471 to 439 my and confirm that Ordovician metamorphism is recorded from the Canadian border south to the Precambrian core of the Green Mountain Anticlinorium (GMA). Medium-high pressure (P) facies series metamorphism in the north and medium-P metamorphism to the south. Similar metamorphic ages and compatible estimates of T and P indicate mafic and pelitic rocks were metamorphosed together. Medium-P Devonian metamorphism has overprinted the Ordovician metamorphism in northern Vermont east and probably west of the GMA axis, resulting in conventional K/Ar, ^(40)Ar/^(39)Ar total fusion and plateau ages of 386 to 355 my on muscovite, biotite, and amphibole. --Modified journal abstract.
Additional Information
© 1984 American Journal of Science. American Journal of Science Online May 1984. We thank Henry Shaw for doing the electron microprobe analyses of the additional samples of mafic schist and James R. Anderson for helping make the amphibole separates. G. P. Kraker, D. H. Rusling, and the operational staff of the U.S. Geological Survey reactor facility managed the fast neutrons required for this study. S. E. Kollman, J. Y. Saburomaru, and J. C. Von Essen assisted with the argon measurements. Theoretical concepts developed by J. B. Thompson, Jr. have been invaluable to our petrologic studies. Discussions with countless New England geologists have helped put the data into geological perspective. Reviews by E. A. Downie, C. V. Guidotti, and J. F. Sutter are sincerely appreciated. We gratefully acknowledge financial support from the National Science Foundation (#DES 69-0064 and EAR 75-03416 to A.L.A.).Additional details
- Eprint ID
- 44919
- Resolver ID
- CaltechAUTHORS:20140414-105654946
- DES 69-0064
- NSF
- EAR 75-03416
- NSF
- Created
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2014-04-14Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences