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Fletcher Mine, Groton, Grafton Co., New Hampshire, USA

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Latitude & Longitude (WGS84): 43° 45' 34'' North , 71° 49' 38'' West
Latitude & Longitude (decimal): 43.75972,-71.82750
GeoHash:G#: drubvw0yc
Locality type:Mine
Köppen climate type:Dfb : Warm-summer humid continental climate

A former open pit mica and feldspar mine.

Mineralization is granite pegmatite, Grafton field. Located near the village of North Groton. (Has produced remarkable examples of hydroxylherderite, strengite, phosphosiderite, strunzite and other pegmatite phosphates.)

Local rocks include rocks of the Littleton Formation, Upper unnamed member.

PLEASE TAKE NOTICE: The Fletcher Mine has been closed to the public since the 1970s. The property is posted against tresspassers. Prosecution will be the result of trespassing. Adjoining property with mines is also privately owned. Please respect wishes of property owners concerned with your safety in mind.

Mineral List

40 valid minerals. 1 (TL) - type locality of valid minerals. 4 erroneous literature entries.

Regional Geology

This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.

Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org

Devonian - Silurian
358.9 - 443.8 Ma

ID: 3184704
Paleozoic intrusive rocks

Age: Paleozoic (358.9 - 443.8 Ma)

Lithology: Intrusive igneous rocks

Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. [154]

Early Devonian
393.3 - 419.2 Ma

ID: 2756282
Littleton Formation, Upper unnamed member

Age: Early Devonian (393.3 - 419.2 Ma)

Stratigraphic Name: Littleton Formation

Description: Light-gray metaturbidite, lithologically identical to, and probably correlative with, the Seboomook Formation of Maine. Coticule layers common.

Comments: 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.

Lithology: Major:{metaclastic}

Reference: Horton, J.D., C.A. San Juan, and D.B. Stoeser. The State Geologic Map Compilation (SGMC) geodatabase of the conterminous United States. doi: 10.3133/ds1052. U.S. Geological Survey Data Series 1052. [133]

Data and map coding provided by Macrostrat.org, used under Creative Commons Attribution 4.0 License

This page contains all mineral locality references listed on mindat.org. This does not claim to be a complete list. If you know of more minerals from this site, please register so you can add to our database. This locality information is for reference purposes only. You should never attempt to visit any sites listed in mindat.org without first ensuring that you have the permission of the land and/or mineral rights holders for access and that you are aware of all safety precautions necessary.


Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
McNair, A. H.; Burnett, C. B.; Headley, J. B., Jr. (1943). Fletcher mica mine, Groton, New Hampshire, USGS Open-File Report 43-63.
Palache, C., Berman, H., & Frondel, C. (1951), The System of Mineralogy of James Dwight Dana and Edward Salisbury Dana, Yale University 1837-1892, Volume II: 868.
Cameron, E.N., Larrabee, D.M., McNair, A.H., et al (1954), USGS Professional Paper 255.
Meyers & Stewart (1956), Geology of New Hampshire, part III.
Moore and Ito (1978), Mineralogical Magazine: 42: 309-323.
Nashua Mineralogical Society Display Catalog (1995).
Korbel & Novak (1999), Min. Encylopaedia: 163.
Rocks & Minerals (2005), New Hampshire Mineral Locality Index: 80: 242-261.
USGS (2005), Mineral Resources Data System (MRDS): U.S. Geological Survey, Reston, Virginia, loc. file ID #10223198.
U.S. Bureau of Mines, Minerals Availability System (MAS) file ID #0330090080.

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