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Map showing publication footprint
  • Usage in publication:
    • Trap Falls Formation
  • Modifications:
    • Named
  • Dominant lithology:
    • Gneiss
    • Schist
  • AAPG geologic province:
    • New England province
Publication:

Crowley, W.P., 1968, The bedrock geology of the Long Hill and Bridgeport quadrangles, Connecticut: Connecticut Geological and Natural History Survey Quadrangle Report, no. 24, 81 p.


Summary:

Trap Falls Formation of Hartland Group named in Fairfield Co., southwestern CT. Consists of leucocratic feldspathic gneiss with interlayered schist and pegmatite. Includes Shelton facies. Overlies Straits Schist; underlies Southington Mountain Formation or Prospect Gneiss. Age is Middle and Late Ordovician.

Source: GNU records (USGS DDS-6; Reston GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Trap Falls Formation*
  • Modifications:
    • Revised
    • Age modified
  • AAPG geologic province:
    • New England province
Publication:

Rodgers, John, 1985, Bedrock geological map of Connecticut: Connecticut Geological and Natural History Survey, scale 1:125,000


Summary:

Trap Falls Formation divided into lower schist and granulite member, Shelton (white gneiss) Member, and Carringtons Pond Member. Age modified to Early and Middle Ordovician.

Source: GNU records (USGS DDS-6; Reston GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Trap Falls Formation
  • Modifications:
    • Revised
  • AAPG geologic province:
    • New England province
Publication:

Sevigny, J.H., and Hanson, G.N., 1993, Orogenic evolution of the New England Appalachians of southwestern Connecticut: Geological Society of America Bulletin, v. 105, no. 12, p. 1591-1605.


Summary:

Shelton Member of Trap Falls Formation (Rodgers, 1985) is here referred to as Shelton muscovite granite . On the basis of field and laboratory studies, Ansonia, Beardsley, Pumpkin Ground, and Shelton gneisses, previously considered stratigraphic units, are reinterpreted as plutonic. Shelton is a foliated, medium-grained, garnet-bearing muscovite leucogranite with a conspicuous white color and abundant garnets. Age of crystallization for the Shelton determined from U-Pb garnet analysis is 380+/-3 Ma (Middle Devonian). Southeast margin of the Shelton is in contact with the Trap Falls Formation. The staurolite-kyanite-grade schists of the Trap Falls Formation contain reversely discordant xenoblastic monazites with 207Pb/235U ages ranging from 385 to 376 Ma and concordant to normally discordant idioblastic monazites that grew approximately 395 Ma. These ages probably represent the range of the Acadian metamorphic thermal peak.

Source: GNU records (USGS DDS-6; Reston GNULEX).


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Asterisk (*) indicates published by U.S. Geological Survey authors.

"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).

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