Putney Volcanics (MADpv;0)

State	Massachusetts
Name	Putney Volcanics
Geologic age	Lower Devonian
Original map label	Dpv
Comments	Part of Connecticut Valley Belt (Silurian and Devonian Rocks). Secondary unit description per MA006 as reported in USGS Geologic Names lexicon (ref. MA024): .Putney Volcanics described as light-greenish-gray to white, very fine grained, poorly foliated phyllite to granulite in a discontinuous belt as much as 130 m wide. Exposed in MA in small area at north end of Deerfield Mesozoic basin. First mapped by Balk (1956) as occurring within his Leyden Argillite [approx the same as present-day Littleton Formation]. Doll and others (1961), in adjacent southern VT, included these rocks in Standing Pond Volcanic Member of Waits River Formation on their Centennial Geologic Map of Vermont, despite that they showed the rocks, as do Zen and others (1983) on the MA State geologic map, at the Gile Mountain-Littleton formational contact, totally isolated from Waits River Formation. Trask (1964) applied the name Standing Pond Volcanics to these rocks in northern MA and southern VT, treating them as a discrete formation. Hepburn (1972), in remapping southeasternmost VT, called the rocks Putney Volcanics in order to distinguish them from other parts of the Standing Pond. Trask (1980) then extended the name Putney into northern MA, and pointed out that Putney Volcanics is not physically traceable into Standing Pond Volcanics. Furthermore, amphibolites in Gile Mountain and Waits River Formations probably correlate with the Standing Pond as they are more mafic in composition. Standing Pond and correlatives in VT and MA are everywhere at or near Waits River-Gile Mountain contact; Putney Volcanics is at or near Gile Mountain-Littleton contact. Further mapping needed to establish continuity between Putney and Standing Pond. Because it is sandwiched in between two Lower Devonian formations, Putney is assigned an Early Devonian age (Hatch and others, 1988).
Primary rock type	phyllite
Secondary rock type	granofels
Other rock types
Lithologic constituents	Major Metamorphic > Granoblastic > Granofelslight greenish-gray plagioclase-quartz-muscovite phyllite and gronofels Metamorphic > Metasedimentary > Metaclastic > Phyllitelight greenish-gray plagioclase-quartz-muscovite phyllite
Map references	Unpublished Digital Geologic Map of Massachusetts received from Rudi Hon at Boston College in 1998.
Unit references	Zen, E-An (ed.), Goldsmith, R. (comp.), Ratcliffe, N.M. (comp.), Robinson, P. (comp.), Stanley, R.S. (comp.), Hatch, N.L., Jr., Shride, A.F., Weed, E.G.A., Wones, D.R., 1983, Bedrock Geologic Map of Massachusetts: U.S. Geological Survey, Reston, VA, scale 1: 250,000. Hatch, N.L., Jr., Robinson, Peter and Stanley, R.S., 1988, Stratigraphy of the Connecticut Valley belt, Chapter B, IN Hatch, N.L., Jr., ed., Bedrock geology of Massachusetts: U.S. Geological Survey Professional Paper, 1366-A-D, p. B1-B34. [http://pubs.er.usgs.gov/publication/pp1366AD] USGS Geologic Names Lexicon (GEOLEX) [http://ngmdb.usgs.gov/Geolex/]
Geographic coverage	Franklin