Biermann Quarries (Bethel quarries) and tourmaline ledge, Bethel, Fairfield Co., Connecticut, USA
|Latitude & Longitude (WGS84):||41° 21' 15'' North , 73° 21' 2'' West|
|Latitude & Longitude (decimal):||41.3541666667, -73.3505555556|
Two adjacent quarries in a granite pegmatite now well-known for its bertrandite crystals. Most references describe or list minerals but provide little history. Todd (1906) visited the "recently opened" quarry and reported that "This vein, we learned, is controlled jointly by the New Jersey Flint and Spar Company and the International Pottery, both of Trenton, New Jersey, and all its stone is shipped there." He mentions an immense tourmaline crystal measuring 3 feet by 18 inches that had been taken from the workings. The quarry apparently was not active during WWII because it does not appear in Cameron et al's (1954) Pegmatite Investigations 1942-45 New England. It may have been worked for beryl in the 1950s. Hiller (1982) claims it was worked in the 19th century for mica and in the early 20th century for mica and feldspar. He collected there after 1965 into the 1980s. It is located in Huntington State Park.
Some references such as Schooner (1961) refer to this quarry incorrectly as the Codfish Hill Quarry, though the minerals he describes are correct for Biermann.
This internally zoned pegmatite has small vugs and pockets in the albite-rich zone containing generally micro-crystals of albite, muscovite, fluorapatite (white to pale blue), smoky quartz, beryl (rarely), and lesser quantities of unusual (for a pegmatite) lead minerals like wulfenite, cerrusite and pyromorphite.
The nearby tourmaline-rich ledge is 100 meters or so away from the pegmatite. The host rock is the Ordovician Taine Mountain Formation chlorite/talc-rich granofels, schist and gneiss. The presence of tourmaline is possibly due to metasomatism of boron rich fluids from the pegmatite into the country rock. However, the ledge is probably too far from the pegmatite for this, and the crystals and matrix are essentially identical to the Taine Mountain Formation-hosted Great Ring Farm tourmaline locality in Newtown http://www.mindat.org/loc-224151.html where there are no known pegmatites. The tourmaline species is reportedly dravite though often labeled as schorl (like Great Ring Farm) and the species at both localities needs study and documentation.
Into the 1980s, collecting permission could be obtained from the park ranger. However, it is no longer allowed. All mineral collecting in Collis P. Huntington State Park is illegal and will be prosecuted.
|Middle Devonian - Ludlow382.7 - 427.4 Ma||Ordovician? granitic gneiss|
Ordovician? granitic gneiss (including local terms Ansonia, Mine Hill, Tyler Lake, Siscowit) - White, light-gray, buff, or pink, generally foliated granitic gneiss, composed of sodic plagioclase, quartz, microcline, muscovite, and biotite, and locally garnet or sillimanite. Commonly contains numerous inclusions or layers of mica schist and gneiss.
Part of Central Lowlands; Iapetus (Oceanic) Terrane - Connecticut Valley Synclinorium Ansonia Gneiss is here referred to as Ansonia leucogranite. On the basis of field and laboratory studies, Ansonia, Beardsley, Pumpkin Ground, and Shelton gneisses, previously considered stratigraphic units, are reinterpreted as plutonic. Ansonia is described as a strongly lineated and moderately foliated, fine-grained, garnet-bearing, biotite-muscovite leucogranite with a well-developed granoblastic texture. Intrudes Beardsley and Pumpkin Ground orthogneisses. Maximum age from zircons is 417+/-1.5 Ma. Conservative interpretation of isotopic data is crystallization between 393 and 419 Ma and therefore, authors assign an age of 406+/-13 Ma (Late Silurian to Early Devonian) to the Ansonia (Sevigny and Hanson, 1993) per CT007.
|Ordovician - Cambrian443.8 - 541 Ma||Cambrian-Ordovician sedimentary|
|Cambrian-Ordovician443.8 - 541 Ma||Cambrian-Ordovician mixed volcanic, volcaniclastic and sedimentary rocks|
Mixed volcanic, volcaniclastic and sedimentary rocks
This designation includes Precambrian iron-formation-bearing sedimentary and volcanic sequences, as well as mixed sedimentary and volcanic or volcaniclastic sequences.
References for regional geology:
Data provided by Macrostrat.org
Garrity, C.P., and Soller, D.R.,. Database of the Geologic Map of North America: adapted from the map by J.C. Reed, Jr. and others (2005). U.S. Geological Survey Data Series 424 .
USGS compilers. State geologic map data. State Maps.
Geological Survey of Canada. Generalized geological map of the world and linked databases. doi:10.4095/195142. Open File 2915d.
22 valid minerals. 1 erroneous literature entry.
Schairer, John F. (1931): Minerals of Connecticut. State Geological and Natural History Survey of Connecticut Bulletin 51.
Sohon, Julian A. (1951): Connecticut Minerals. State Geological and Natural History Survey of Connecticut Bulletin 77.
Schooner, Richard. (1958): The Mineralogy of the Portland-East Hampton-Middletown-Haddam Area in Connecticut (With a few notes on Glastonbury and Marlborough). Published by Richard Schooner; Ralph Lieser of Pappy’s Beryl Shop, East Hampton; and Howard Pate of Fluorescent House, Branford, Connecticut.
Januzzi, Ronald E. (1959): The Minerals of Western Connecticut and Southeastern New York. The Mineralogical Press, Danbury, Connecticut.
Januzzi, Ronald E. (1959): Wulfenite and Cerussite at Bethel, Connecticut. The American Mineralogist, Vol. 14, No. 11-12.
Jones, Robert W. Jr., (1960): Luminescent Minerals of Connecticut, a Guide to Their Properties and Locations. Fluorescent House. Branford, Connecticut
Schooner, Richard. (1961): The Mineralogy of Connecticut. Fluorescent House, Branford, Connecticut.
Hiller, John, Jr. (1971): Connecticut Mines and Minerals. Privately published.
Henderson, William A., Jr. (1975): The Bertrandites of Connecticut. The Mineralogical Record, Vol. 6, No. 3, pp. 114-123.
Januzzi, Ronald E. (1976): Mineral Localities Connecticut and Southeastern New York State. The Mineralogical Press, Danbury, Connecticut.
Ryerson, Kathleen H. (1976): Rock Hound’s Guide to Connecticut. Pequot press.
Hiller, John. (1982), The Biermann Quarry. Jewelry Making Gems and Minerals: (534).
Cruson, Daniel. (1991): Feldspar Quarries and the Mining History of Newtown. The Rooster’s Crow, Newtown Historical Society.
Januzzi, Ronald E. (1994): Mineral Data Book, Western Connecticut and Environs. The Mineralogical Press, Danbury, Connecticut.
Henderson, William A., Jr. (1995): The Microminerals of Connecticut. Rocks & Minerals (Connecticut Issue), vol. 70, no. 6, pp. 420-425.
Weber, Marcelle H. and Earle C. Sullivan (1995): Connecticut Mineral Locality Index. Rocks & Minerals (Connecticut Issue), Vol. 70, No. 6, p. 396.