Rb-Sr whole-rock and /sup 40/Ar//sup 39/Ar mineral ages of the Hartland stock, south-central Maine: a post-Acadian representative of the New Hampshire Plutonic series
Journal Article
·
· Am. J. Sci.; (United States)
- Univ. of Georgia, Athens
The Hartland granodioritic stock is an undeformed, post-Acadian representative of the New Hampshire Plutonic series that intrudes low-grade Silurian-Devonian (.) metasedimentary rocks in south-central Maine. A nine-point, Rb-Sr whole-rock isochron defines an age of 360 +/- 8 m.y. for the pluton (initial /sup 87/Sr//sup 86/Sr = 0.7056 +/- 3). Biotite and hornblende from the pluton display undisturbed /sup 40/Ar//sup 39/Ar age spectra with mutually overlapping dates of 362 +/- 5 m.y. (seven samples). The undisturbed character of the argon isotopic systems suggests that the /sup 40/Ar//sup 39/Ar ages date times of post-magmatic cooling through temperatures required for retention of argon. Comparison of the emplacement age defined for the Hartland stock with Rb-Sr whole-rock isochron dates reported for crystallization of other New Hampshire Series plutons suggests continuous Devonian intrusive activity in New England, preceding, during, and following the Acadian orogeny. No geochronologic evidence for separating distinct subseries of intrusion can be provided with presently available data.
- OSTI ID:
- 5130406
- Journal Information:
- Am. J. Sci.; (United States), Journal Name: Am. J. Sci.; (United States) Vol. 282:1; ISSN AJSCA
- Country of Publication:
- United States
- Language:
- English
Similar Records
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Excess /sup 40/Ar in minerals of a shallow pluton, the Mount St. Hilaire complex, Quebec
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Conference
·
Sun Feb 28 23:00:00 EST 1993
· Geological Society of America, Abstracts with Programs; (United States)
·
OSTI ID:5579280
Excess /sup 40/Ar in minerals of a shallow pluton, the Mount St. Hilaire complex, Quebec
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·
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· Geol. Soc. Am., Abstr. Programs; (United States)
·
OSTI ID:6595311
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Journal Article
·
Tue Dec 31 23:00:00 EST 1974
· J. Res. U.S. Geol. Surv., v. 3, no. 2, pp. 229-231
·
OSTI ID:4152731
Related Subjects
58 GEOSCIENCES
580100* -- Geology & Hydrology-- (-1989)
AGE ESTIMATION
ALKALI METALS
ALKALINE EARTH ISOTOPES
ARGON 39
ARGON 40
ARGON ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
DEVONIAN PERIOD
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FEDERAL REGION I
GEOLOGIC AGES
GRANITES
GRANODIORITES
HOURS LIVING RADIOISOTOPES
IGNEOUS ROCKS
INTERMEDIATE MASS NUCLEI
INTRUSION
ISOMERIC TRANSITION ISOTOPES
ISOTOPE DATING
ISOTOPES
LIGHT NUCLEI
MAGMA
MAINE
METALS
METAMORPHIC ROCKS
NORTH AMERICA
NUCLEI
PALEOZOIC ERA
PLUTONIC ROCKS
RADIOISOTOPES
ROCKS
RUBIDIUM
SILURIAN PERIOD
STABLE ISOTOPES
STRONTIUM 86
STRONTIUM 87
STRONTIUM ISOTOPES
USA
YEARS LIVING RADIOISOTOPES
580100* -- Geology & Hydrology-- (-1989)
AGE ESTIMATION
ALKALI METALS
ALKALINE EARTH ISOTOPES
ARGON 39
ARGON 40
ARGON ISOTOPES
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
DEVONIAN PERIOD
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
FEDERAL REGION I
GEOLOGIC AGES
GRANITES
GRANODIORITES
HOURS LIVING RADIOISOTOPES
IGNEOUS ROCKS
INTERMEDIATE MASS NUCLEI
INTRUSION
ISOMERIC TRANSITION ISOTOPES
ISOTOPE DATING
ISOTOPES
LIGHT NUCLEI
MAGMA
MAINE
METALS
METAMORPHIC ROCKS
NORTH AMERICA
NUCLEI
PALEOZOIC ERA
PLUTONIC ROCKS
RADIOISOTOPES
ROCKS
RUBIDIUM
SILURIAN PERIOD
STABLE ISOTOPES
STRONTIUM 86
STRONTIUM 87
STRONTIUM ISOTOPES
USA
YEARS LIVING RADIOISOTOPES