- Usage in publication:
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- Lahore Complex
- Modifications:
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- Overview
- AAPG geologic province:
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- Piedmont-Blue Ridge province
Summary:
Description of Lahore Complex based on Pavlides (1982; 1990). Divided into three map units: amphibole monzonite; pyroxene monzonite; and mafic and ultramafic rocks. Amphibole monzonite is mesocratic, medium-grained, and has a foliation defined by alignment of tabular feldspar crystals. Pyroxene monzonite is dark-gray to black, fine- to medium grained, massive to vaguely-foliated. Mafic and ultramafic rocks consist of partially serpentinized pyroxenite containing diopside rimmed by antigorite or by tremolite. In contact with Mine Run Complex and Ellisville biotite granodiorite. Map symbol indicates an Ordovician age.
Source: GNU records (USGS DDS-6; Reston GNULEX).
- Usage in publication:
-
- Lahore Complex*
- Modifications:
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- Named
- Dominant lithology:
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- Monzonite
- Pyroxenite
- AAPG geologic province:
-
- Piedmont-Blue Ridge province
Summary:
Lahore Complex formally named for community in Orange Co., central VA. Used informally by Pavlides (1989). Consists of Lahore pluton and mafic pluton that Lahore pluton partially encloses. In north-central part of Lahore pluton, saprolite of amphibole monzonite is exposed in roadcuts near Lahore. Fresh bedrock of amphibole monzonite is mostly found along streams or their nearby enclosing slopes. Pyroxene monzonite bedrock of the Lahore pluton is exposed in fields along west side of US Hwy 522 near north end of pluton. Rocks of the mafic pluton poorly exposed in a few places at its north end. Intrudes Cambrian and (or) Ordovician Mine Run Complex melange zones II and III. A combination of U-Pb (zircon), Rb/Sr (whole-rock isochron), and 40Ar/39Ar (age spectra and isochrons of amphiboles) geochronologic data supports an age of about 450 Ma for the Lahore pluton. Age of Lahore Complex is Cambrian and (or) Ordovician. Report includes geologic maps.
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 ([ ]).