Alligator Back Formation - Banded marble

Light- and dark-gray, laminated fine to medium-grained marble, calcareous gneiss, and schist. Mineralogy: calcite + quartz + biotite + muscovite + plagioclase + pyrite + magnetite-ilmenite. Thick to thin beds of marble are interlayered with graphitic phyllite and mica schist; the lithology grades from impure marble to calcareous metagraywacke depending on per cent age of detrital calcite present. The unit includes the Arch Marble of Brown (1958) and the Archer Creek Formation of Espenshade (1954).
State Virginia
Name Alligator Back Formation - Banded marble
Geologic age Proterozoic Z-Cambrian
Lithologic constituents
Major
Metamorphic > Metasedimentary > Metacarbonate > Marble
Incidental
Metamorphic > Gneiss
Metamorphic > Schist
Comments Lynchburg Group; Blue Ridge Anticlinorium (Southwest)
References

Virginia Division of Mineral Resources, 1993, Geologic Map of Virginia: Virginia Division of Mineral Resources, scale 1:500,000.

Virginia Division of Mineral Resources, 2003, Digital Representation of the 1993 Geologic Map of Virginia, Publication 174, CD ROM (ISO-9660) contains image file, expanded explanation in pdf, and ESRI shapefiles, scale 1:500,000.

NGMDB product
Counties Amherst - Appomattox - Bedford - Buckingham - Campbell - Franklin - Nelson - Pittsylvania - Lynchburg