Opelika Complex; Auburn Gneiss

Fine-grained biotite-oligoclase gneiss intermixed with coarse-grained muscovite-biotite schist; locally contains muscovite-rich pegmatite.
State Alabama
Name Opelika Complex; Auburn Gneiss
Geologic age Precambrian to Paleozoic
Lithologic constituents
Major
Metamorphic > Schist > Mica-schistintermixed with coarse-grained muscovite-biotite schist; Unit commonly grades to medium to coarse-grained muscovite-biotite schist, locally garnetiferous.
Metamorphic > Gneiss > Biotite-gneissfine-grained biotite-oligoclase gneiss
Minor
Igneous > Plutonic > Granitic > Leucocratic-granitic > Pegmatitelocally contains muscovite-rich pegmatite.
Comments Printed map has units 'oa' and 'oas' in one description; split them up here.
References

Szabo, M.W., Osborne, E.W., Copeland, C.W. Jr., and Neathery, T.L., 1988, Geologic Map of Alabama, Geological Survey of Alabama Special Map 220, scale 1:250,000.

NGMDB product
Counties Chambers - Lee