|Name||Littleton Formation, Lower unnamed member|
|Geologic age||Lower Devonian|
Metamorphic > MetasedimentaryThinly or poorly bedded aluminous lower part (of Littleton Formation), somewhat rusty.
Metamorphic > Metaigneous > MetavolcanicThinly or poorly bedded aluminous lower part (of Littleton Formation), somewhat rusty.
Metamorphic > Metasedimentary > Metaclastic > Quartziterare quartzite lentils
|Comments||Secondary unit description from the USGS Geologic Names lexicon (Ref. NH047): Used as Early Devonian (Siegenian) Littleton Formation. Mapped as 10 unnamed subdivisions and one undivided unit. Undivided Littleton consists of gray metapelite and metawacke with subordinate metavolcanics generally, but not everywhere, conformable with underlying Fitch or Madrid Formations. Fossiliferous in western NH. Subdivisions include a lower unnamed member probably correlative with Carrabassett Formation of northwestern ME; metaconglomerate and quartzite that is locally fossiliferous (at Dalton Mountain); graphitic-sulfidic metashale in Piermont allochthon of northwestern NH; calc-silicate rock that is locally fossiliferous (at Mt. Moosilauke) and is possibly equivalent in part to Hildreths Formation of ME; epiclastic or resedimented metavolcanic sediments; metabasaltic greenstone or amphibolite; metarhyolite, some of it in subvolcanic intrusions; a unit consisting of rhyolitic and keratophyric metatuff and meta-agglomerate, volcaniclastic metagraywacke, and minor basalt; volcanic lentils, both mafic and felsic; and an upper unnamed member consisting of light-gray metaturbidite with common coticule, lithologically identical to, and probably correlative with Seboomook Formation of ME. Ironbound Mountain Formation is a probable facies equivalent to lower part of Littleton. Report includes geologic map and correlation chart, cross sections, and four 1:500,000-scale derivative maps. Part of the Central Maine Composite Terrane (Central Maine Trough) - Variably metamorphosed sedimentary and volcanic rocks of greenschist to granulite facies, locally migmatized. Area includes structural belts between the Monroe fault on the west and the Campbell Hill fault on the east; that is, the Bronson Hill anticlinorium, Piedmont allochthon, Kearsarge-central Maine synclinorium, central New Hampshire anticlinorium, and Rochester-Lebanon (Maine) antiformal synclinorium. Granite pegmatite, Holderness quadrangle (point within formation): 393+/-? U/Pb, monazite per NH030.|
Lyons, J.B., Bothner, W.A., Moench, R.H., and Thompson, J.B., Jr., 1997, Bedrock Geologic Map of New Hampshire: Reston, VA, U.S. Geological Survey Special Map, 2 sheets, scale 1:250,000.
Eusden, J.D., Jr., and Barreiro, Barbara, 1988, The timing of peak high-grade metamorphism in central-eastern New England: Maritime Sediments and Atlantic Geology, v. 24, p. 241-255.
USGS Geologic Names lexicon found at: http://ngmdb.usgs.gov/Geolex/
|Counties||Cheshire - Grafton - Merrimack - Sullivan|