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Alkali Feldspar Leucogranite

Alkali feldspar leucogranite
StateVirginia
NameAlkali Feldspar Leucogranite
Geologic ageProterozoic Y
Original map labelYal
CommentsBlue Ridge Basement Complex, Middle Proterozoic (Grenville-Age) Plutonic Rocks. From expanded explanation (ref. VA002): Alkali-feldspar leucogranite. Leucocratic, coarse grained to megacrystic, equigranular to porphyritic granite contains white alkali feldspar phenocrysts and interstitial blue quartz, with accessory biotite, pyroxene, and garnet; primary flow-banding is locally delineated by aligned feldspar phenocrysts. Geophysical signature: positive radiometric anomaly. This lithology occurs as dikes and discrete plutons, comprises migmatitic leucosomes within early or pre-Grenville age layered gneisses, and occurs as xenoliths with in some Grenville-age plutonic rocks. This is a lithologic unit that likely includes rocks spanning a range of ages.
Primary rock typegranite
Secondary rock type
Other rock types
Lithologic constituents
Major
Igneous > Plutonic > Granitic > Leucocratic-granitic
Map references
Digital Representation of the 1993 Geologic Map of Virginia", 2003, CD ROM (ISO-9660) contains image file, expanded explanation in pdf, and ESRI shapefiles, viewing software not included. This is a digital version of "Geologic Map of Virginia" published in 1993. Available from: https://www.dmme.virginia.gov/commerce/
Unit references
Virginia Division of Mineral Resources, 1993, Geologic Map of Virginia: Virginia Division of Mineral Resources, scale 1:500,000
Digital Representation of the 1993 Geologic Map of Virginia - expanded explanation: 2003, Commonwealth of Virginia, Department of Mines, Minerals, and Energy, Divsion of Mineral Resources, Publication 147, 85 pp
Digital Representation of the 1993 Geologic Map of Virginia", 2003, CD ROM (ISO-9660) contains image file, expanded explanation in pdf, and ESRI shapefiles, viewing software not included. This is a digital version of "Geologic Map of Virginia" published in 1993. Available from: https://www.dmme.virginia.gov/commerce/
Geographic coverageAlbemarle - Amherst - Bedford - Greene - Madison - Nelson - Rappahannock - Warren

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