USGS - science for a changing world

Mineral Resources On-Line Spatial Data

Mineral Resources > Online Spatial Data > Geology > by state > Massachusetts

Straw Hollow Diorite and Assabet Quartz Diorite undifferentiated

Straw Hollow Diorite and Assabet Quartz Diorite undifferentiated - Gray, medium-grained, slightly-foliated biotite-hornblende diorite and quartz diorite. Intrudes OZn.
StateMassachusetts
NameStraw Hollow Diorite and Assabet Quartz Diorite undifferentiated
Geologic ageSilurian
Original map labelSsaqd
CommentsPart of Nashoba Zone (Silurian and Older Rocks) Straw Hollow Diorite and Assabet Quartz Diorite are shown on MA State bedrock geologic map by Zen and others (1983) as one unit because of their similar occurrence and general lithology and small size. Straw Hollow covers only 3 sq km. Intrudes Nashoba Formation; in fault contact with Marlboro Formation. Described as light gray to dark green, medium grained, and weakly foliated. Age is Silurian based on lithologic similarity to Sharpners Pond Diorite, dated at 430 +/-5 Ma by U-Pb methods on zircon (Zartman and Naylor, 1984) (Wones and Goldsmith, 1991) per MA007.
Primary rock typediorite
Secondary rock typequartz diorite
Other rock types
Lithologic constituents
Major
Igneous > Plutonic > Dioritic > Quartz-dioritemedium-grained, slightly-foliated biotite-hornblende diorite and quartz diorite
Igneous > Plutonic > Dioritic > Dioritemedium-grained, slightly-foliated biotite-hornblende diorite and quartz diorite
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Unpublished Digital Geologic Map of Massachusetts received from Rudi Hon at Boston College in 1998.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.
Wones, D.R. and Goldsmith, Richard, 1991, Intrusive rocks of eastern Massachusetts, Chapter I, IN Hatch, N.L., Jr., ed., The bedrock geology of Massachusetts: U.S. Geological Survey Professional Paper, 1366-E-J, p. I1-I61.
Geographic coverageMiddlesex

Show this information as [XML] - [JSON]

AccessibilityFOIAPrivacyPolicies and Notices

Take Pride in America logoUSA.gov logoU.S. Department of the Interior | U.S. Geological Survey
URL: http://mrdata.usgs.gov/geology/state/sgmc-unit.php?unit=MASsaqd;0
Page Contact Information: Peter Schweitzer