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Mineral Resources > Online Spatial Data > Geology > by state > Alabama Geology

Geologic units in Lee county, Alabama

Eutaw Formation (Cretaceous) at surface, covers 3 % of this area

Eutaw Formation - Light-greenish-gray to yellowish-gray cross-bedded, well-sorted, micaceous, fine to medium quartz sand that is fossiliferous and glauconitic in part and contains beds of greenish-gray micaceous, silty clay and medium-dark-gray carbonaceous clay. Light-gray glauconitic fossiliferous sand, thin beds of sandstone, and massive accumulations of fossil oyster shells occur locally in the upper part of the formation in western AL (Tombigbee Sand Member). In eastern AL thin to thick-bedded accumulations of the fossil oyster Ostrea cretacea Morton occur throughout much of the formation.

Lithology: sand; clay or mud; sandstone;

Pine Mountain Group; Hollis Quartzite (Precambrian to Paleozoic) at surface, covers 2 % of this area

Hollis Quartzite - quartzite containing minor mica, feldspar, and pyrite; locally arkosic; commonly sheared.

Lithology: quartzite

High terrace deposits (Pleistocene) at surface, covers < 0.1 % of this area

High terrace deposits - Varicolored lenticular beds of poorly sorted sand, ferruginous sand, silt, clay, and gravelly sand. Sand consists primarily of very fine to very coarse poorly sorted quartz grains; gravel composed of quartz, quartzite, and chert pebbles.

Lithology: terrace

Opelika Complex; Auburn Gneiss (Precambrian to Paleozoic) at surface, covers 10 % of this area

Auburn Gneiss - fine-grained biotite-oligoclase gneiss intermixed with coarse-grained muscovite-biotite schist; locally contains muscovite-rich pegmatite.

Lithology: felsic gneiss; mica schist; pegmatite

Motts Gneiss, Unnamed unit (Precambrian to Paleozoic) at surface, covers 0.3 % of this area

Motts Gneiss, Unnamed unit - unnamed unit comprised of masses of epidote-hornblende-oligoclase mylonitic gneiss and amphibolite.

Lithology: gneiss; amphibolite

Dadeville Complex; Ropes Creek Amphibolite (Precambrian to Paleozoic) at surface, covers 8 % of this area

Ropes Creek Amphibolite - layered and massive amphibolite; locally includes hornblende migmatite and ultramafic pods.

Lithology: amphibolite; migmatite; ultramafic intrusive rock

Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones (Precambrian to Paleozoic) at surface, covers 12 % of this area

Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones - blastomylonite, mylonite gneiss, locally includes mylonite schist and mylonite quartzite in Towaliga fault zone.

Lithology: mylonite; gneiss; schist; quartzite

Wacoochee Complex; Whatley Mill Gneiss (Precambrian to Paleozoic) at surface, covers 6 % of this area

Whatley Mill Gneiss - variably mylonitized coarse-grained biotite-muscovite-oligoclase gneiss with large potassium feldspar augen.

Lithology: augen gneiss

Opelika Complex; Auburn Gneiss, Unnamed unit (Precambrian to Paleozoic) at surface, covers 1 % of this area

Opelika Complex; Auburn Gneiss, Unnamed unit - unnamed unit comprised of masses of medium- to coarse-grained muscovite-biotite schist, locally garnetiferous; grades into oa.

Lithology: mica schist

Pine Mountain Group; Chewacla Marble (Precambrian to Paleozoic) at surface, covers 0.1 % of this area

Chewacla Marble - light-gray coarse to fine-grained dolomite marble; locally rich in phlogopite.

Lithology: marble

Uchee Complex; Phenix City Gneiss (Precambrian to Paleozoic) at surface, covers 4 % of this area

Phenix City Gneiss - biotite-epidote quartz diorite gneiss and biotite-hornblende gneiss; locally includes migmatitic amphibolite; cut by numerous granitic veins.

Lithology: felsic gneiss; mafic gneiss; amphibolite; granite

Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones (Precambrian to Paleozoic) at surface, covers 0.2 % of this area

Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones - crushed schistose rock; includes sericite-graphite-rich rocks.

Lithology: mylonite; cataclasite

Dadeville Complex; Camp Hill Granite Gneiss (Precambrian to Paleozoic) at surface, covers 0.7 % of this area

Camp Hill Granite Gneiss - coarse to medium-grained foliated granite to quartz diorite (tonalite) gneiss, locally biotite-rich; locally contains thin amphibolite pods and lenses. Boundary between Rock Mills Granite Gneiss and Camp Hill Granite Gneiss arbitrarily defined.

Lithology: granitic gneiss; amphibolite

Wacoochee Complex; Halawaka Schist (Precambrian to Paleozoic) at surface, covers 4 % of this area

Halawaka Schist - feldspathic muscovite-biotite schist and quartz-diorite gneiss; locally contains lenses of muscovite-graphite schist and amphibolite; commonly cut by feldspathic veins and pegmatites.

Lithology: mica schist; gneiss; pegmatite

Wacoochee Complex; Phelps Creek Gneiss (Precambrian to Paleozoic) at surface, covers 1.0 % of this area

Phelps Creek Gneiss - quartz monzonite to granite gneiss in dikes and sheets with wide migmatite zones at contacts.

Lithology: quartz monzonite; granitic gneiss; migmatite

Tuscaloosa Group undifferentiated (Cretaceous) at surface, covers 21 % of this area

Tuscaloosa Group undifferentiated - Light-gray to moderate-reddish-orange clayey, gravelly fine to very coarse sand; massive mottled sandy clay; local wood and leaf beds; and thin beds of indurated sandstone. Gravel consists mainly of quartz and quartzite and range in size from very fine pebbles to large cobbles. Mapped eats of the Tallapoosa River.

Lithology: sand; clay or mud; sandstone; gravel; quartzite

Pine Mountain Group; Manchester Schist (Precambrian to Paleozoic) at surface, covers 5 % of this area

Manchester Schist - interlayered muscovite-quartz schist and quartzite, locally contains garnet, sillimanite and graphite; commonly intensely shared.

Lithology: schist; quartzite

Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones (Precambrian to Paleozoic) at surface, covers 2 % of this area

Mylonitic and Cataclastic Rocks in the Brevard, Towaliga, and Goat Rock Fault Zones - mylonite and blastomylonite; contains minor ultramylonite, mylonite schist, and mylonite gneiss.

Lithology: mylonite; schist; gneiss

Opelika Complex; Bottle Granite (Precambrian to Paleozoic) at surface, covers 5 % of this area

Bottle Granite - leucocratic, fine to medium-grained, well-foliated quartz monzonite to granite; locally porphyritic.

Lithology: quartz monzonite; granite

Biotite Gneiss (Precambrian-Paleozoic) at surface, covers < 0.1 % of this area

Biotite gneiss

Lithology: biotite gneiss

Opelika Complex; Loachapoka Schist (Precambrian to Paleozoic) at surface, covers 4 % of this area

Loachapoka Schist - muscovite-quartz schist; locally contains biotite-garnet-muscovite schist, many layers conatin sillimanite (northeast of Mount Jefferson, Lee County); kyanite (west of Mount Jefferson); locally muscovite-rich schist and quartzite common.

Lithology: mica schist; quartzite

Motts Gneiss (Precambrian to Paleozoic) at surface, covers 4 % of this area

Motts Gneiss - leucocratic quartz-rich quartz diorite pencil gneiss.

Lithology: felsic gneiss

Alluvial, coastal and low terrace deposits (Holocene) at surface, covers 1.0 % of this area

Alluvial, coastal and low terrace deposits - Varicolored fine to coarse quartz sand containing clay lenses and gravel in places. Gravel composed of quartz and chert pebbles and assorted metmorphic and igneous rock fragments in streams near the Piedmont. In areas of the Valley and Ridge province gravel composed of angular to subrounded chert, quartz, and quartzite pebbles. Coastal deposits include fine to medium quartz sand with shell fragments and accessory heavy minerals along Gulf beaches and fine to medium quartz sand, silt, clay, peat, mud and ooze in the Mississippi Sound, Little Lagoon, bays, lakes, streams, and estuaries.

Lithology: beach sand; alluvium

Dadeville Complex; Waverly Gneiss (Precambrian to Paleozoic) at surface, covers 3 % of this area

Waverly Gneiss - feldspathic biotite-hornblende gneiss with thin layers of amphibolite, calc-silicate rock, garnet quartzite, and muscovite schist; locally rich in manganese.

Lithology: mafic gneiss; amphibolite; quartzite; mica schist; calc-silicate rock

Uchee Complex; Hospilika Granite (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area

Hospilika Granite - leucocratic, massive epidote-muscovite quartz diorite to granodiorite; weak flow banding, sharp contacts.

Lithology: quartz diorite; granodiorite

Mylonite and ultramylonite (Age not given) at surface, covers < 0.1 % of this area

Mylonite and ultramylonite

Lithology: mylonite

Moffits Mill Schist (Precambrian to Paleozoic) at surface, covers 0.1 % of this area

Moffits Mill Schist - interlayered biotite-epidote-muscovite-quartz schist, metagraywacke, and quartzite.

Lithology: schist; metasedimentary rock; quartzite