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National Geologic Map Database
Map showing publication footprint
  • Usage in publication:
    • Ellsworth Schist*
  • Modifications:
    • Overview
  • AAPG geologic province:
    • New England province
Publication:

Rankin, D.W. (editor), Chiarenzelli, J.R., Drake, A.A., Jr., Goldsmith, Richard, Hall, L.M., Hinze, W.J., Isachsen, Y.W., Lidiak, E.G., McLelland, James, Mosher, Sharon, Ratcliffe, N.M., Secor, D.T., Jr., and Whitney, P.R., 1993, Proterozoic rocks east and southeast of the Grenville Front, IN Reed, J.C., Jr., and others, eds., Precambrian; conterminous U.S.: Geological Society of America, The Geology of North America, The Decade of North American Geology (DNAG), v. C-2, p. 335-461.


Summary:

Ellsworth Schist is of Late Proterozoic to Ordovician age. Islesboro Formation is considered a distal facies of North Haven Greenstone, Ellsworth Schist, and schist at Columbia Falls (eastern coastal ME). Consists of interbedded grayish-green phyllite and white to gray, siliceous, feldspathic siltstone (Berry and Osberg, 1989).

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


Map showing publication footprint
  • Usage in publication:
    • Ellsworth Schist*
  • Modifications:
    • Age modified
    • Geochronologic dating
  • AAPG geologic province:
    • New England province
Publication:

Stewart, D.B., and Tucker, R.D., 1999, Geology of northern Penobscot Bay, Maine; with contributions to geochronology: U.S. Geological Survey Miscellaneous Investigations Series Map, I-2551, 1 sheet, scale 1:62,500


Summary:

Age of Ellsworth Schist changed to Cambrian. Pb-U date on zircon from tuff within Ellsworth is 509+/-2 Ma (R.D. Tucker, written commun., 1995). Rb-Sr whole-rock age is 499+/-15 Ma (recalculated from Brookins, 1976). Age of Castine Volcanics, which contains clasts of Ellsworth, may be as old as Early Ordovician (Ruitenberg and others, 1993), thus indicating an earlier age for Ellsworth.

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


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

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 ( ).

Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).

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