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U. S. Route 7 Expressway (Danbury line to Iron Works District), Brookfield, Fairfield Co., Connecticut, USA
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Latitude: 41°27'4"N
Longitude: 73°23'42"W
 
 
The expressway section of U. S. Route 7 extending from Interstate 84 in Danbury to exit 12 at U. S. Route 202 in Brookfield was constructed between 1974 and 1976. The section from the Danbury/Brookfield line (from just north of the Agstone Co. marble quarry) to exit 12 at U. S. Route 202 (apparently the "Iron Works district" in Brookfield) traverses mostly sediments along the Still River and not much apparent bedrock. One roadcut is visible on the right of the northbound lanes, about 1 mile south of exit 12. However, Januzzi (1976) and (1994) reports a long list of minerals, many repeated in Weber and Sullivan (1995).

In Januzzi (1994) he shows photos of several minerals from the Iron Works district, apparently from exit 12, then the northern terminus of this stretch of expressway (which has since been extended further north), where bedrock evidently was encountered. Clarke (1958) shows outcrops in the area of exit 12, mapped as dolomitic marble of the Inwood (now called Stockbridge) marble, mixed with "younger granite" (now mapped as granite Proterozoic granitic gneiss).

Although the identical list of minerals in Januzzi (1976) and (1994) says all the minerals are from the U. S. Route 7 expressway construction, details accompanying photos in Januzzi (1994) indicate some came from pegmatites in the "Iron Works District", some locations "undisclosed". Because no one else has documented the specific localities and minerals, that information has largely been lost. That is unfortunate because, as Januzzi (1994) states:

The author’s research there not only confirms Shepard’s spodumene discovery in the area in 1835 (Shepard, 1837) but also establishes, in the record, a whole series of minerals that have previously not been reported including chrysoberyl, beryl, beryl var. morganite, triphylite, hydroxyfluorapatite, dickinsonite, bertrandite, as well as a number of common species.


The coordinates are for the approximate mid-point of this stretch of highway.

Mineral List

Actinolite
Albite
var: Andesine
'Allanite'
Almandine
Anatase
Anglesite
Aragonite
Arsenopyrite
Augite
Bertrandite
Beryl
'Biotite'
Calcite
Cerussite
Chalcopyrite
'Chlorite Group'
Chondrodite
Chrysoberyl ?
Chrysotile
Clinozoisite
Dickinsonite-(KMnNa)
Diopside
Dolomite
Elbaite
Epidote
Fluorapatite
Forsterite
Galena
Greenockite
Hematite ?
Hemimorphite ?
'Hornblende'
Hydrozincite ?
Ilmenite
'K Feldspar
var: Adularia' ?

Kyanite
'Limonite'
Magnetite
Microcline
Molybdenite
Muscovite
var: Sericite
Opal
var: Opal-AN

Orthoclase
Palygorskite
Phlogopite
Pyrite
Pyromorphite
Pyrrhotite
Quartz
Rutile
'Scapolite'
Schorl
'Serpentine Group'
Sillimanite
Sphalerite
Spodumene
Staurolite
Talc
Titanite
'Tourmaline'
Tremolite
Triphylite
Vivianite
Wollastonite
Zircon
Zoisite


68 entries listed. 56 valid minerals.

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References

Shepard, Charles U. (1837), A Report on the Geological Survey of Connecticut. Hamlen, New Haven.

Clarke, James W. (1958): The Bedrock Geology of the Danbury Quadrangle. State Geological and Natural History Survey of Connecticut Quadrangle Report No. 7.

Schooner, Richard. (1961), The Mineralogy of Connecticut. Fluorescent House, Branford, Connecticut.

Januzzi, Ronald E. (1976): Mineral Localities of Connecticut and Southeastern New York State. The Mineralogical Press, Danbury, Connecticut: 185.

Januzzi, Ronald E. (1994), Mineral Data Book - Western Connecticut and Environs. The Mineralogical Press, Danbury, Connecticut.

Weber, Marcelle H. and Earle C. Sullivan. (1995): Connecticut Mineral Locality Index. Rocks & Minerals (Connecticut Issue): 70(6): 397.

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Copyright © Jolyon Ralph and Ida Chau 1993-2014. Site Map. Locality, mineral & photograph data are the copyright of the individuals who submitted them. Site hosted & developed by Jolyon Ralph. Mindat.org is an online information resource dedicated to providing free mineralogical information to all. Mindat relies on the contributions of thousands of members and supporters. Mindat does not offer minerals for sale. If you would like to add information to improve the quality of our database, then click here to register.
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