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Map showing publication footprint
  • Usage in publication:
    • Occoquan granite
  • Modifications:
    • Named
  • Dominant lithology:
    • Granite
  • AAPG geologic province:
    • Piedmont-Blue Ridge province
Publication:

Lonsdale, J.T., 1927, Geology of the gold-pyrite belt of the northeastern Piedmont, Virginia: Virginia Geological Survey Bulletin, no. 30, 110 p.


Summary:

Described here as greenish-gray, coarse-grained and horizontally sheeted granite. Exposed along Occoquan Run, from village of Occoquan to forks of Bull Run and at other places. Capped by crystalline schist. Age is Precambrian.

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


Map showing publication footprint
  • Usage in publication:
    • Occoquan granite
  • Modifications:
    • Overview
    • Geochronologic dating
  • AAPG geologic province:
    • Piedmont-Blue Ridge province
Publication:

Rader, E.K., and Evans, N.H., 1993, Geologic map of Virginia; expanded explanation: Virginia Division of Mineral Resources, 80 p.


Summary:

Occoquan used informally on the State map. Described as light-gray, medium- to coarse-grained, muscovite-biotite monzogranite and lesser granodiorite and tonalite. In many places the rock has a strong quartz-rod lineation, and locally, two foliations. Intrudes Popes Head Formation, Lunga Reservoir Formation, Accotink Schist, and Sykesville Formation. The Occoquan has been dated recently at 479+/-9 Ma (U-Pb single-crystal zircon; J.N. Aleinikoff, written communication, 1993). Map symbol indicates a Cambrian and Ordovician age.

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


Map showing publication footprint
  • Usage in publication:
    • Occoquan Granite*
  • Modifications:
    • Age modified
    • Geochronologic dating
  • AAPG geologic province:
    • Piedmont-Blue Ridge province
Publication:

Drake, A.A., Jr., and Froelich, A.J., 1997, Geologic map of the Falls Church quadrangle, Fairfax and Arlington Counties and the City of Falls Church, Virginia, and Montgomery County, Maryland: U.S. Geological Survey Geologic Quadrangle Map, GQ-1734, 1 sheet, scale 1:24,000


Summary:

Occoquan Granite intrudes Indian Run Formation in adjoining Annandale 7.5-min quad. Mose and Nagel (1982) determined an Rb-Sr whole-rock isochron age for Occoquan of 494+/-14 Ma. Preliminary U-Pb dating of zircon suggests that Occoquan may be Early Ordovician (J.N. Aleinikoff, 1992, oral commun.).

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


Map showing publication footprint
  • Usage in publication:
    • Occoquan Granite*
  • Modifications:
    • Age modified
    • Geochronologic dating
  • AAPG geologic province:
    • Piedmont-Blue Ridge province
Publication:

Drake, A.A., Jr., Southworth, Scott, and Lee, K.Y., 1999, Geologic map of the Seneca quadrangle, Montgomery County, Maryland, and Fairfax and Loudoun Counties, Virginia: U.S. Geological Survey Geologic Quadrangle Map, GQ-1802, 1 sheet, scale 1:24,000


Summary:

Occoquan Granite has an age of 484/-8 Ma [Early Ordovician] based on weighted average of 236Pb/238U ion microprobe ages of ten zircons.

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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