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  • Usage in publication:
    • Franklinville Gneiss
  • Modifications:
    • Named
  • Dominant lithology:
    • Gneiss
  • AAPG geologic province:
    • Piedmont-Blue Ridge province
Publication:

Crowley, W.P., 1976, The geology of the crystalline rocks near Baltimore and its bearing on the evolution of the eastern Maryland Piedmont: Maryland Geological Survey Report of Investigations, no. 27, 40 p.


Summary:

Name Franklinville Gneiss proposed for medium- to coarse-grained biotite-quartz-plagioclase gneiss that overlies Bradshaw Layered Amphibolite of the Baltimore Mafic Complex in a northeast-southwest syncline in White Marsh quad, Baltimore Co., MD. At Franklinville, rock contains sparse, and very small "mafic inclusions." However, 300 m north-northwest of the Franklinville bridge, unit includes cobble-size clasts of calc-silicate fels. Also includes several occurrences of deformed chlorite schist in zones up to 15 m across. Equivalent to Port Deposit Gneiss in adjacent Harford Co. Age given as Cambrian-Ordovician(?).

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 ( ).

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