Latitude & Longitude (WGS84):	43° 40' 14'' North , 71° 0' 29'' West
Latitude & Longitude (decimal):	43.67056,-71.00806
GeoHash:	G#: drv82jvx2
Locality type:	Mine
Köppen climate type:	Dfb : Warm-summer humid continental climate

Granite pegmatite. Opened in 1877. Mined for mica, feldspar, and beryl.

The Ham and Weeks Educational and Recreational Area is currently operated by the Maine Mineralogical and Geological Society (MMGS). The site is leased by MMGS, and access is limited to MMGS members. According to the MMGS website:

"Ham and Weeks Mine was first developed by the Mineral Hill Mining Corporation, formed August 7, 1877, by Samuel B. Ames. Shares were sold to buy equipment and mining rights in the area. Originally called the Mica Mine, 2 or 3 acres were worked and the mica was sold for use in stove windows and lamp chimneys. Operations didn’t last too long. As the pit depth increased, an underground spring flooded the pit, and pumps couldn’t keep up with the flow. The original pit is believed to be south of the present pit. The mine was inactive until 1914 or 1915, when the present pit was opened for mica to be used in gas masks for soldiers in WW I. The mica was taken by horse-drawn carts to East Wakefield and loaded unto trains. The mine was closed after a year or two, then re-opened a third time in the 1930’s, when mica was used as electrical insulation in early crystal radio sets; beryl was also reportedly mined for war use."

Cameron et. al. (1954) described the deposit, referred to as the Weeks Feldspar Quarry (named for the owner, Raymond B. Weeks of Burleysville [sic], N.H.): "in the 1920's...feldspar, scrap mica, and beryl were recovered. In the early 1930's, a Mr. Day, Kittery, Maine, operated the quarry for feldspar and scrap mica...In September 1942, J. D. Bardill, District Engineer for the Bureau of Mines, arranged a sampling program under the direction of E. E. Maillot and W. H. Evans. The Bureau of Mines quarried beryl from the north and west sides of the pit, dug 10 small pits and trenches, and drilled 5 horizontal jackhammer holes 12 to 16 feet long in an effort to locate the contacts of the pegmatite. They also pumped out the flooded part of the pit."

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

Pennsylvanian - Mississippian 298.9 - 358.9 Ma ID: 2942029

Two-mica granite of the Sebago batholith and Effingham pluton of eastern New Hampshire Age: Carboniferous (298.9 - 358.9 Ma) Description: Sebago batholith = 325+/-? Rb/Sr per NH026. 325+/-3 U/Pb per NH017. 298+/-2 U/Pb per J.N. Aleinikoff, oral commun., Dec. 24, 1992. Effingham pluton = 325+/-? Rb/Sr per NH026. Comments: Original map source: Bennett, D.S., Wittkop, C.A., and Dicken, C.L., 2006, Bedrock Geologic Map of New Hampshire - A Digital Representation of the Lyons and others 1997 map and ancillary files: U.S. Geological Survey Data Series 215, CD-ROM, scale 1:250,000. Lithology: Major:{granite} 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]

Devonian - Silurian 358.9 - 443.8 Ma ID: 3185212

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]

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

References

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