USGS Home
Contact USGS
Search USGS

Mineral Resources > Online Spatial Data > Geology > by state > New Hampshire Geology

Geologic units in Sullivan county, New Hampshire

[Additional scientific data in this geographic area]

Gile Mountain Formation, undivided (Lower Devonian) at surface, covers 6 % of this area

Gile Mountain Formation, undivided - Gray to tan metawacke and schist or phyllite; gradational into Meetinghouse Slate Member but more thickly bedded and less pelitic than the member. Includes minor metavolcanic lentils.

Lithology: schist; metasedimentary rock; phyllite; slate; metavolcanic rock

Granite, granodiorite, and trondhjemite (Late Ordovician) at surface, covers 4 % of this area

Granite, granodiorite, and trondhjemite.

Lithology: granite; granodiorite; trondhjemite

Concord Granite (Late Devonian ) at surface, covers 1 % of this area

Concord Granite - Gray two-mica granite, locally grading to tonalite.

Lithology: granite; tonalite

Littleton Formation (Devonian) at surface, covers < 0.1 % of this area

Littleton Formation - Gray slate and phyllite containing interbeds of gray schistose quartzite 1/4 inch to 6 inches thick. West of Guildhall are lustrous, light to dark gray biotite-garnet phyllite and schist, some slate, and subordinate quartzite and impure quartzite. South of Bellows Falls gray phyllite passes eastward into gray mica schist containing porphyroblasts of biotite, garnet, and staurolite.

Lithology: slate; phyllite; quartzite; schist; mica schist

Littleton Formation, Volcanic lentils (Lower Devonian) at surface, covers < 0.1 % of this area

Littleton Formation, Volcanic lentils - Both mafic and felsic

Lithology: mafic metavolcanic rock; felsic metavolcanic rock

Kinsman Granodiorite (Early Devonian ) at surface, covers 9 % of this area

Kinsman Granodiorite - (Kinsman Quartz Monzonite of Billings, 1955) - Foliated granite, granodiorite, tonalite, and minor quartz diorite; large megacrysts of potassium feldspar characteristic; garnet locally abundant.

Lithology: granite; granodiorite; tonalite; quartz diorite

Fitch Formation (Upper Silurian; Pridolian and Ludlovian) (Upper Silurian - (Pridolian and Ludlovian)) at surface, covers 0.8 % of this area

Fitch Formation - Metamorphosed limestone, calcareous sandstone, siltstone, and dark pelitic schist; lower contact is disconformable on the Clough Quartzite. Fossiliferous.

Lithology: marble; quartzite; phyllite; pelitic schist

Metavolcanic and metasedimentary rocks of the lower part of Ammonoosuc Volcanics, undivided (Middle Ordovician) at surface, covers 0.3 % of this area

Metavolcanic and metasedimentary rocks of the lower part of Ammonoosuc Volcanics, undivided.

Lithology: metavolcanic rock; metasedimentary rock

Littleton Formation, Lower unnamed member (Lower Devonian) at surface, covers 2 % of this area

Littleton Formation, Lower unnamed member - Thinly or poorly bedded aluminous lower part, somewhat rusty. Rare quartzite lentils. Carrabassett Formation in northwestern Maine is probably correlative.

Lithology: metasedimentary rock; metavolcanic rock; quartzite

Ammonoosuc Volcanics (Ordovician) at surface, covers < 0.1 % of this area

Ammonoosuc Volcanics - Fine-grained chloritic and biotitic gneiss and greenstone in areas north of Bellows Falls; biotite gneiss and amphibolite south of Bellows Falls. (Southeastern Vermont).

Lithology: biotite gneiss; greenstone; amphibolite

Upper part of Rangeley Formation (Lower Silurian (Llandoverian)) at surface, covers 2 % of this area

Upper part of Rangeley Formation - Rusty-weathering, pelitic schist, metasandstone, and local coarse-grained metasandstone lentils; calc-silicate pods common; minor coticule. Probably equivalent to member C of Rangeley Formation of Maine.

Lithology: pelitic schist; metasedimentary rock; calc-silicate rock

Granodiorite to tonalite (Late Ordovician) at surface, covers 0.2 % of this area

Granodiorite to tonalite.

Lithology: granodiorite; tonalite

Spaulding Tonalite (Early Devonian) at surface, covers 0.5 % of this area

Spaulding Tonalite (Spaulding Quartz Diorite of Fowler-Billings, 1949) - Weakly foliated to nonfoliated, spotted biotite quartz diorite, tonalite, granodiorite, and granite; garnet and muscovite may or may not be present.

Lithology: quartz diorite; tonalite; granodiorite; granite

Gile Mountain Formation (Devonian) at surface, covers < 0.1 % of this area

Gile Mountain Formation - Gray quartz-muscovite phyllite or schist, interbedded and intergradational with gray micaceous quartzite (graywacke northeast of Nulhegan River), calcareous mica schist, and, locally, quartzose and micaceous crystalline limestone like that of the Waits River formation. The phyllite and schist commonly contain porphyroblasts of biotite, garnet, or staurolite, and locally kyanite, andalusite, or sillimanite. Used as Early Devonian Gile Mountain Formation. Generally consists of gray to tan metawacke and schist or phyllite, gradational into its Meetinghouse Slate Member, but much more thickly bedded and less pelitic. Contains minor metavolcanic lentils. Unnamed metavolcanic member is possibly equivalent to Putney Volcanics of southeastern VT. Separately mapped interbedded gray slate or phyllite and brown-weathering calcite-ankerite metasiltstone, and minor marble and quartzite, resembles Waits River Formation of VT. Meetinghouse Slate Member consists of gray to black phyllite and silty metasandstone turbidite. Report includes geologic map, cross sections, correlation chart, and four 1:500,000-scale derivative maps (Lyons and others, 1997).

Lithology: phyllite; mica schist; quartzite; limestone; graywacke

Partridge Formation, Interstratified metavolcanic rocks (Middle - Upper Ordovician) at surface, covers 0.2 % of this area

Partridge Formation, Interstratified metavolcanic rocks - Chiefly amphibolites, found in southwestern New Hampshire.

Lithology: amphibolite; metavolcanic rock

Partridge Formation, undivided (Middle - Upper Ordovician) at surface, covers 8 % of this area

Partridge Formation, undivided - Black, rusty-weathering sulfidic-graphitic slate or schist and sparse to abundant metagraywacke. Lies stratigraphically between upper and lower parts of the Ammonoosuc Volcanics.

Lithology: slate; schist; metasedimentary rock

Fitch and Clough Formations, undivided (Silurian) at surface, covers 2 % of this area

Fitch and Clough Formations, undivided.

Lithology: quartzite; marble; meta-conglomerate; sandstone; mica schist; siltstone; pelitic schist; marble

Lower part of Rangeley Formation (Lower Silurian (Llandoverian)) at surface, covers 3 % of this area

Lower part of Rangeley Formation - Gray, thinly laminated (5-25 mm) metapelite with local lentils of turbidites and thin quartz conglomerates in western New Hampshire. Sparse calc-silicate pods and coticule. Probably equivalent to member B of Rangeley Formation of Maine.

Lithology: meta-argillite; meta-conglomerate; calc-silicate rock

Littleton Formation, Metaconglomerate and quartzite (Lower Devonian) at surface, covers 0.1 % of this area

Littleton Formation, Metaconglomerate and quartzite - Locally fossiliferous in Whitefield quadrangle.

Lithology: meta-conglomerate; quartzite

Gile Mountain Formation, Interbedded gray slate or phyllite and brown-weathering calcite-ankerite metasiltstone (Lower Devonian) at surface, covers 1 % of this area

Interbedded gray slate or phyllite and brown-weathering calcite-ankerite metasiltstone - Contains minor marble and quartzite. Resembles Waits River Formation in Vermont.

Lithology: slate; phyllite; metasedimentary rock; marble; quartzite

Clough Quartzite (Lower Silurian (upper Llandoverian)) at surface, covers 2 % of this area

Clough Quartzite - Orthoquartzite, quartz metaconglomerate, muscovite schist, minor polymictic metaconglomerate. Disconformable below Fitch Formation and unconformable on Ordovician formations. Equivalent, in part, to member C of Rangeley Formation of Maine. Fossiliferous.

Lithology: quartzite; meta-conglomerate; mica schist

Gile Mountain Formation, Mafic metavolcanic member (Lower Devonian ) at surface, covers 0.8 % of this area

Mafic metavolcanic member - Possibly equivalent to Putney Volcanics of southeastern Vermont.

Lithology: mafic metavolcanic rock

Gile Mountain Formation, Meetinghouse Slate Member (Lower Devonian ) at surface, covers 0.4 % of this area

Meetinghouse Slate Member - Gray to black phyllite and silty metasandstone turbidite.

Lithology: phyllite; metasedimentary rock

Trondhjemite (Late Ordovician) at surface, covers 2 % of this area

Trondhjemite - Contains biotite and hornblende.

Lithology: trondhjemite

Member C (uppermost) of the Rangeley Formation in Maine and northeastern and southwestern New Hampshire (Lower Silurian (Llandoverian)) at surface, covers 0.3 % of this area

Member C (uppermost) of the Rangeley Formation in Maine and northeastern and southwestern New Hampshire - Quartz-pebble conglomerate overlain by rusty metapelite and feldspathic quartzite.

Lithology: conglomerate; meta-argillite; quartzite

Bethlehem Granodiorite (Early Devonian) at surface, covers 30 % of this area

Bethlehem Granodiorite (Bethlehem Gneiss of Billings, 1955) - Gray, strongly foliated biotite-muscovite granodiorite and associated tonalite and granite.

Lithology: granodiorite; tonalite; granite

Littleton Formation, Upper unnamed member (Lower Devonian) at surface, covers 0.4 % of this area

Littleton Formation, Upper unnamed member - Light-gray metaturbidite, lithologically identical to, and probably correlative with, the Seboomook Formation of Maine. Coticule layers common.

Lithology: metasedimentary rock

Littleton Formation, undivided (Lower Devonian; Siegenian) at surface, covers 13 % of this area

Littleton Formation undivided - Gray metapelite and metawacke and subordinate metavolcanic rocks; generally, but not everywhere, conformable with underlying Fitch or Madrid Formations. Fossiliferous in western New Hampshire.

Lithology: metasedimentary rock; metavolcanic rock

Ammonoosuc Volcanics, Bimodal volcanic rocks (Middle - Upper Ordovician) at surface, covers 10 % of this area

Ammonoosuc Volcanics, Bimodal volcanic rocks - Locally includes unmapped Oals.

Lithology: bimodal suite

Clough Formation (Silurian) at surface, covers < 0.1 % of this area

Clough Formation - Quartzite, quartz-conglomerate, and mica schist; lenses of fossiliferous calcareous quartzite in upper part. (Southeastern Vermont).

Lithology: conglomerate; quartzite; mica schist