| State | Massachusetts |
|---|---|
| Name | Fitchburg Complex |
| Geologic age | Lower Devonian or younger |
| Lithologic constituents |
Major
Igneous > Plutonic > Granitic > Granitemuscovite-bearing granite; may include some granite of late Paleozoic age
Minor
Igneous > Plutonic > Granitic > Leucocratic-granitic > Pegmatitecommonly contains white pegmatite bearing muscovite and tourmaline
|
| Comments | Part of Merrimack Belt (Silurian, Devonian and Pennsylvanian Rocks). Secondary unit description per MA007 as reported in USGS Geologic Names lexicon (ref. MA024): Fitchburg Complex mapped as three small stocks intruding Worcester Formation east of Wekepeke fault and west of Clinton. Also intrudes Paxton and Littleton Formations. U-Pb zircon age of 390 +/-15 Ma and Rb-Sr whole-rock age of 402 +/-11 Ma were both reported by Zartman and Naylor (1984) (Wones and Goldsmith, 1991). |
| 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 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.https://pubs.er.usgs.gov/publication/pp1366EJ USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/https://ngmdb.usgs.gov/Geolex/search |
| NGMDB product | |
| Counties | Middlesex - Worcester |