USGS Home
Contact USGS
Search USGS

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

Geologic units in Belknap county, New Hampshire

[Additional scientific data in this geographic area]

Augite monzodiorite (Jurassic) at surface, covers 2 % of this area

Augite monzodiorite.

Lithology: monzodiorite

Upper part of Rangeley Formation (Lower Silurian (Llandoverian)) at surface, covers 27 % 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

Mesoperthitic biotite granite (Early Cretaceous) at surface, covers 0.8 % of this area

Mesoperthitic biotite granite - Pink Conway-type granite of Kingsley (1931).

Lithology: granite

Porphyritic syenite (Jurassic) at surface, covers 1 % of this area

Porphyritic syenite - Hastingsite or hornblende and (or) hedenbergite are present.

Lithology: syenite

Winnipesaukee Tonalite (Early Devonian) at surface, covers 16 % of this area

Winnipesaukee Tonalite (Winnipesaukee Quartz Diorite of Billings, 1955) - Gray, massive to foliated tonalite and minor quartz diorite, granodiorite, and granite. Probably coeval with Spaulding Tonalite.

Lithology: tonalite; quartz diorite; granodiorite; granite

Rangeley Formation, Ribbon-banded calc-silicate of eastern New Hampshire (Lower Silurian (Llandoverian)) at surface, covers 0.2 % of this area

Rangeley Formation, Ribbon-banded calc-silicate of eastern New Hampshire - Probably equivalent to Patch Mountain Member of the Sangerville Formation (Llandoverian and Wenlockian) of central Maine.

Lithology: calc-silicate rock

Kinsman Granodiorite (Early Devonian ) at surface, covers 16 % 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

Concord Granite (Late Devonian ) at surface, covers 6 % of this area

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

Lithology: granite; tonalite

Rhyolite and fine-grained granite (Cretaceous) at surface, covers < 0.1 % of this area

Rhyolite and fine-grained granite - Includes some ignimbritic caldera-fill and minor intrusive rocks (part of Ossipee Mountain Complex of Kingsley, 1931); also some aphanitic gray, black, or tan quartz-feldspar porphyry.

Lithology: rhyolite; granite; ignimbrite; porphyry

Quartz syenite (Jurassic) at surface, covers 2 % of this area

Quartz syenite - Commonly porphyritic and mesoperthitic; contains biotite and, locally, fayalite, hastingsite, hornblende, or ferrohedenbergite.

Lithology: quartz syenite

Moat Volcanics (Middle Jurassic?) at surface, covers 0.1 % of this area

Moat Volcanics - Bedded and ignimbritic tuffs, flows, and breccias; also porphyritic rhyolite and minor trachyte.

Lithology: ignimbrite; ash-flow tuff; volcanic breccia (agglomerate); rhyolite; trachyte

Gabbro (Jurassic) at surface, covers < 0.1 % of this area

Gabbro - Has varying amounts of olivine, augite, and hornblende.

Lithology: gabbro

Porphyritic biotite granite (Cretaceous) at surface, covers 0.2 % of this area

Porphyritic biotite granite - Pink to gray; hastingsite or riebeckite in some varieties.

Lithology: granite

Littleton Formation, undivided (Lower Devonian; Siegenian) at surface, covers < 0.1 % 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

Smalls Falls Formation, undivided (Upper to Middle Silurian (Ludlovian and Wenlockian)) at surface, covers 0.2 % of this area

Smalls Falls Formation, undivided -Very rusty weathering, thinly bedded sulfidic-graphitic schist and pyrrhotitic calc-silicate granofels. Eastern facies equivalent to lower part of the Fitch Formation. Locally mapped as Francestown Formation of Nielson (1981) in southern New Hampshire.

Lithology: schist; granofels

Lower part of Rangeley Formation (Lower Silurian (Llandoverian)) at surface, covers 20 % 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

Hornblende-biotite quartz monzodiorite (Jurassic) at surface, covers < 0.1 % of this area

Hornblende-biotite quartz monzodiorite - Composition ranges from quartz monzonite to diorite.

Lithology: quartz monzodiorite; quartz monzonite; diorite

Porphyritic granite (Jurassic) at surface, covers 0.7 % of this area

Porphyritic granite.

Lithology: granite

Diorite (Jurassic) at surface, covers 1 % of this area

Diorite - Contains hornblende, biotite, and hedenbergite.

Lithology: diorite

Perry Mountain Formation, undivided (Lower? - Middle? Silurian) at surface, covers 6 % of this area

Perry Mountain Formation, undivided - Sharply interbedded quartzites, light-gray nongraphitic metapelite, and "fast-graded" meta-turbidites. Coticule layers common.

Lithology: quartzite; meta-argillite; metasedimentary rock

Conway Granite (Middle - Late? Jurassic) at surface, covers 2 % of this area

Conway Granite - Typically pink, coarse-grained mesoperthitic biotite (amphibole-free) granite; locally fine-grained or porphyritic.

Lithology: granite