Government Pit (Government Gravel Pits), Albany, Carroll Co., New Hampshire, USA
|Latitude & Longitude (WGS84):||44° 0' 15'' North , 71° 9' 43'' West|
|Latitude & Longitude (decimal):||44.00417,-71.16194|
Granite pegmatite associated with the Conway granite. - The "gravel" is decomposed granite pegmatite from in-situ ledges. It is the "rotten stone" ledges which collectors have worked. (Note: This site is often erroneously cited as being in either Conway or North Conway.)
30 valid minerals. 1 erroneous literature entry.
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
|Late Jurassic - Middle Jurassic|
145 - 174.1 Ma
Age: Jurassic (145 - 174.1 Ma)
Stratigraphic Name: Conway Granite
Comments: Part of the White Mountain igneous province of McHone and Butler (1984) - Overall part of the White Mountain Plutonic-Volcanic Suite - Includes Cretaceous alkalic syenite to granitic to gabbroic plutons, minor volcanic rocks, and lamprophyre dikes of the New England-Quebec igneous province of McHone and Butler (1984); also includes Jurassic granite and syenite and less abundant quartz syenite, diorite, gabbro, nepheline syenite, and volcanic rocks of the White Mountain igneous province of McHone and Butler (1984). Middle - Late? Jurassic White Mountain Plutonic-Volcanic Suite: Gore Mountain granitic intrusive rocks = 169+/-3 K/Ar per NH013. Percy pluton = 166+/-4 K/Ar per NH013. Pliny Range intrusive rocks = 182+/-4 and 189+/-5 K/Ar per NH013; also 183+/-2 Ar/Ar per NH019. Cannon Mountain pluton = 184+/-4 K/Ar per NH022 and 194+/-4 K/Ar per NH013. Conway Granite = 183+/-5, 182+/-4, 180+/-4, 178+/-4, 171+/-4, and 155+/-4 K/Ar per NH023. Mad River pluton = 178+/-5 K/Ar, 158+/-4 Rb/Sr, biotite, per NH022.Belknap intrusive rocks = 159+/-3 K/Ar per NH022. 161+/-5 Rb/Sr and 158+/-3 K/Ar, biotite, per NH013. 169.3+/-1.7 Rb/Sr per NH033.
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. 
Bearss, Gene and Janules, Bob (1992): Miarolitic Cavity Minerals of the Govemment Pit, Albany, New Hampshire (Rocks & Minerals 67:158-169).
Camp, Kristen F. (2011), "Mineralogy and Geochemistry of Anorogenic Granitic Miarolitic Pegmatites Associated with the White Mountain Intrusive Suite, New Hampshire." University of New Orleans Theses and Dissertations. Paper 1363.