- Usage in publication:
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- Mascoma Granite*
- Modifications:
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- Overview
- Age modified
- Geochronologic dating
Summary:
Used as Mascoma Granite of Oliverian Plutonic Suite. Not separately mapped on 1:250,000-scale geologic map, but shown on 1:500,000-scale map showing plutons and sample localities for isotopic dating. Isotope age of 431 +/-30 Ma [Silurian per time scale of Palmer, 1983] by Rb/Sr methods and of 450 +/-25 Ma [Ordovician and Silurian per Palmer, 1983] by U/Pb methods are both reported by Naylor (1969). Authors assign age of Late Ordovician and Silurian to entire Oliverian Plutonic Suite in this report; therefore, age of Mascoma is here assigned the same age. Report includes geologic map, cross sections, correlation chart, and four 1:500,000-scale derivative maps.
Source: GNU records (USGS DDS-6; Reston GNULEX).
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).