Deerfield Basalt (MAJdb;0)

State	Massachusetts
Name	Deerfield Basalt
Geologic age	Lower Jurassic
Lithologic constituents	Major Igneous > Volcanic > Mafic-volcanic > Basalt (Flow-pillows)Well-jointed quartz tholeiite, locally vesicular and locally pillowed near base.
Comments	Part of Mesozoic Basins (Jurassic and Triassic Rocks); Sedimentary and Volcanic Rocks of Deerfield and Northfield Basins. Secondary unit description per MA003 as reported in USGS Geologic Names lexicon (ref. MA024): The Deerfield Diabase is here redefined as Deerfield Basalt of the Newark Supergroup to reflect its extrusive origin, shown by pillows and pillow breccias at the base, and by vesicular pahoehoe flows at the top. The Triassic-Jurassic boundary is arbitrarily drawn at the base of the Deerfield in clastic rocks of the Sugarloaf Formation (Robinson and Luttrell, 1985).
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., and Wones, D.R., 1983, Bedrock Geologic Map of Massachusetts: U.S. Geological Survey, Reston, VA, scale 1: 250,000. https://pubs.er.usgs.gov/publication/70046713 Robinson, Peter and Luttrell, G.W., 1985, Revision of some stratigraphic names in central Massachusetts, IN Stratigraphic notes, 1984: U.S. Geological Survey Bulletin, 1605-A, p. A71-A78. https://pubs.er.usgs.gov/publication/b1605A USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/ https://ngmdb.usgs.gov/Geolex/search
NGMDB product	NGMDB product page for 16357
Counties	Franklin

State

Name

Deerfield Basalt

Geologic age

Lower Jurassic

Lithologic constituents

Major

Igneous > Volcanic > Mafic-volcanic > Basalt (Flow-pillows)Well-jointed quartz tholeiite, locally vesicular and locally pillowed near base.

Comments

Part of Mesozoic Basins (Jurassic and Triassic Rocks); Sedimentary and Volcanic Rocks of Deerfield and Northfield Basins. Secondary unit description per MA003 as reported in USGS Geologic Names lexicon (ref. MA024): The Deerfield Diabase is here redefined as Deerfield Basalt of the Newark Supergroup to reflect its extrusive origin, shown by pillows and pillow breccias at the base, and by vesicular pahoehoe flows at the top. The Triassic-Jurassic boundary is arbitrarily drawn at the base of the Deerfield in clastic rocks of the Sugarloaf Formation (Robinson and Luttrell, 1985).

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., and Wones, D.R., 1983, Bedrock Geologic Map of Massachusetts: U.S. Geological Survey, Reston, VA, scale 1: 250,000.

https://pubs.er.usgs.gov/publication/70046713

Robinson, Peter and Luttrell, G.W., 1985, Revision of some stratigraphic names in central Massachusetts, IN Stratigraphic notes, 1984: U.S. Geological Survey Bulletin, 1605-A, p. A71-A78.

https://pubs.er.usgs.gov/publication/b1605A

USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/

https://ngmdb.usgs.gov/Geolex/search

NGMDB product

NGMDB product page for 16357

Counties

Franklin