USGS Home
Contact USGS
Search USGS

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

Geologic units in Coosa county, Alabama

Alluvial, coastal and low terrace deposits (Holocene) at surface, covers 0.1 % 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

Wedowee Group; Wedowee Group undifferentiated (Precambrian to Paleozoic) at surface, covers 8 % of this area

Wedowee Group undifferentiated - Wedowee Group undifferentiated includes the Cragford Phyllite and Cutnose Gneiss. Cragford Phyllite -- interbedded fine-grained graphite-chlorite-sericite schist and phyllite, garnet-sericite schist and phyllite, graphite-quartz-sericite phyllite, locally feldspathic biotite gneiss, calc-silicate rock, and quartzite. Cutnose Gneiss -- cyclically interbedded fine-grained quartz-biotite feldspathic gneiss, graphite-chlorite-sericite schist, locally thin interbeds of graphite-quartz-sericite phyllite, and quartzite. Rocks in the area northeast of Clanton in Chilton and Coosa Counties that are here assigned to the Wedowee Group also have been interpreted as part of the Higgins Ferry Group.

Lithology: schist; phyllite; felsic gneiss; quartzite; calc-silicate rock

Hatchet Creek Group; Hanover Schist (Precambrian to Paleozoic) at surface, covers 4 % of this area

Hanover Schist - coarse to fine-grained feldspathic biotite-sericite-quartz-muscovite schist, commonly containing staurolite, garnet, and locally sillimanite in northeastern outcrop areas includes zones of aluminous graphite schist, hornblende quartzite, garnet quartzite, and rare amphibolite. Schist commonly retrograded to sericite-garnet-quartz schist. Numerous granitic pegmatites.

Lithology: schist; quartzite; pegmatite; amphibolite

Hissop Granite (Precambrian to Paleozoic) at surface, covers 3 % of this area

Hissop Granite - mesocratic to leucocratic, strongly lineated granite to granodiorite.

Lithology: granite; granodiorite

Talladega Group; Lay Dam Formation, unnamed diamictite facies (Silurian?-Devonian) at surface, covers 1 % of this area

Talladega Group; Lay Dam Formation, unnamed diamictite facies - Unnamed diamictite facies of Lay Day Formation in Coosa and Chilton Counties consists of cobbles and boulders of carbonate, pelitic rocks, quartzite, chert, felsic plutonic rocks, and gneiss in a metagraywacke matrix.

Lithology: conglomerate; carbonate; mudstone; quartzite; chert; plutonic rock (phaneritic); gneiss; metasedimentary rock

Rockford Granite (Precambrian to Paleozoic) at surface, covers 6 % of this area

Rockford Granite - leucocratic granite, granodiorite, and trondhjemite; locally well foliated, numerous pegmatites. Includes unnamed granitoids in Chilton County.

Lithology: granite; granodiorite; trondhjemite; pegmatite

Mitchell Dam Amphibolite (Precambrian to Paleozoic) at surface, covers 3 % of this area

Mitchell Dam Amphibolite - dark-green to black fine to coarse-grained, thin-layered to massive hornblende-actinolite amphibolite; includes all amphibolite associated with the Higgins Ferry and Hatchet Creek Groups.

Lithology: amphibolite

Talladega Group; Butting Ram Sandstone (Silurian?-Devonian) at surface, covers 0.5 % of this area

Butting Ram Sandstone - white to light-bluish-gray medium to coarse-grained, locally conglomeratic thick-bedded quartzose sandstone. Possible Devonian fossils.

Lithology: sandstone; conglomerate

Newala Limestone (Ordovician) at surface, covers 0.4 % of this area

Newala Limestone - light to dark-gray thick-bedded micritic and peloidal limestone and minor dolomite.

Lithology: limestone; dolostone (dolomite)

Sylacauga Marble Group; Shelvin Rock Church Formation (Cambrian?-Ordovician?) at surface, covers < 0.1 % of this area

Shelvin Rock Church Formation - moderate-pink to light-gray calcite and locally dolomite marble.

Lithology: marble

Emuckfaw Group; Emuckfaw Group undifferentiated in part (Precambrian to Paleozoic) at surface, covers 2 % of this area

Emuckfaw Group undifferentiated in part - interbedded muscovite +/- garnet-biotite schist, metagraywacke, calc-silicate rock, and quartzite; rare thin amphibolite. Includes thin layers of aluminous graphitic schist. Locally sheared to mylonite schist.

Lithology: mica schist; metasedimentary rock; quartzite; calc-silicate rock; amphibolite

Hillabee Greenstone, unnamed dacite unit (Paleozoic) at surface, covers 0.2 % of this area

Hillabee Greenstone, unnamed dacite unit - unnamed unit comprised of masses of well-foliated quartz dacite.

Lithology: dacite

Kahatchee Mountain Group; Waxahatchee Slate (Precambrian?-Cambrian?) at surface, covers < 0.1 % of this area

Waxahatchee Slate - dark-gray to grayish-green thin-bedded, micaceous metasiltstone, slate, and fine-grained quartzite.

Lithology: metasedimentary rock; slate; quartzite

Kahatchee Mountain Group; Brewer Phyllite (Precambrian?-Cambrian?) at surface, covers < 0.1 % of this area

Brewer Phyllite - dusky-red micaceous slate and phyllite, locally containing interbedded micaceous arkosic quartzite and metasiltstone; locally at the base is interbedded calcite and dolomite marble.

Lithology: slate; phyllite; quartzite; metasedimentary rock; marble

Sylacauga Marble Group; Gooch Branch Chert (Cambrian?-Ordovician?) at surface, covers < 0.1 % of this area

Gooch Branch Chert - light-gray to light-brown dolomite marble associated with abundant light-gray to white massive to moderately foliated metachert.

Lithology: marble; metasedimentary rock

Kahatchee Mountain Group; Stumps Creek Formation (Precambrian?-Cambrian?) at surface, covers 0.3 % of this area

Stumps Creek Formation - grayish-green micaceous metasiltstone and minor phyllite; grayish-green fine to medium-grained pyritic metasandstone in middle to upper part.

Lithology: phyllite; metasedimentary rock

Sylacauga Marble Group; Jumbo Dolomite (Cambrian?-Ordovician?) at surface, covers 0.4 % of this area

Jumbo Dolomite - light to medium-gray thin to thick-bedded dolomite marble; contains intraclast-bearing dolomite, locally sandy in middle part.

Lithology: marble; dolostone (dolomite); sand

Zana Granite (Precambrian to Paleozoic) at surface, covers 0.9 % of this area

Zana Granite - quartz monzonite to granite with strong gneissic texture, cut by small pegmatites and aplite dikes, generally elongate; semiconcordant to foliation of country rock.

Lithology: quartz monzonite; granite; pegmatite; aplite

Higgins Ferry Group; Roscoelite-graphite-quartz schist and graphitic quartzite (Precambrian to Paleozoic) at surface, covers 10 % of this area

Higgins Ferry Group; Roscoelite-graphite-quartz schist and graphitic quartzite

Lithology: schist; quartzite

Hatchet Creek Group; Pinchoulee Gneiss (Precambrian to Paleozoic) at surface, covers 10 % of this area

Pinchoulee Gneiss - medium to fine-grained migmatitic, locally garnetiferous biotite-feldspar gneiss, commonly saturated with granitic pods.

Lithology: felsic gneiss; granite

Kahatchee Mountain Group; Wash Creek Slate (Precambrian?-Cambrian?) at surface, covers 0.5 % of this area

Wash Creek Slate - grayish-green to black micaceous, partly carbonaceous to graphitic slate and metasiltstone containing interbedded light-gray to light-brown fine to coarse-grained metasandstone.

Lithology: slate; metasedimentary rock

Hillabee Greenstone (Paleozoic) at surface, covers 3 % of this area

Hillabee Greenstone - pale-green to light-olive-brown massive, fine-grained greenstone interbedded locally with well-foliated mafic phyllite.

Lithology: greenstone; phyllite

Higgins Ferry Group; Garnet quartzite (garnetite) and garnitiferous altered mafic rock (Precambrian to Paleozoic) at surface, covers 0.1 % of this area

Higgins Ferry Group; Garnet quartzite (garnetite) and garnitiferous altered mafic rock.

Lithology: quartzite; metamorphic rock

Higgins Ferry Group (Precambrian to Paleozoic) at surface, covers 9 % of this area

Higgins Ferry Group - thinly layered coarse to fine-grained biotite-feldspar-quartz gneiss, sericite-feldspar-muscovite schist, +/- biotite +/- garnet-muscovite schist, and biotite-garnet feldspathic gneiss; locally common pegmatites.

Lithology: felsic gneiss; mica schist; pegmatite

Kowaliga Gneiss (Precambrian to Paleozoic) at surface, covers 0.6 % of this area

Kowaliga Gneiss - coarse-grained granodiorite to quartz monzonite with large plagioclase augen; generally shared among margins.

Lithology: granodiorite; quartz monzonite

Wedowee Group; Hackneyville Schist (Precambrian to Paleozoic) at surface, covers 0.1 % of this area

Hackneyville Schist - medium to coarse-grained quartz-plagioclase +/- almandine +/- kyanite +/- biotite-muscovite schist, graphite-muscovite-quartz schist, and quartzite containing biotite. Large porphyroblasts of muscovite, andalusite and/or chiastrolite common. Rocks in the areas between Goodwater in Coosa County and Millerville in Clay County that are here assigned to the Hackneyville Schist also have been interpreted as part of the Higgins Ferry Group.

Lithology: schist; quartzite

Talladega Group; Jemison Chert and Chulafinnee Schist undifferentiated (Silurian?-Devonian) at surface, covers 5 % of this area

Jemison Chert and Chulafinnee Schist undifferentiated - grayish-white to yellowish-orange massive, thick-bedded, fine-grained, locally argillaceous, locally fossiliferous metachert and light to dark-greenish-gray fine to medium-grained fissile quartz-sericite-chlorite phyllite and schist which locally includes thin chlorite phyllite and quartzose phyllite beds.

Lithology: schist; phyllite; metasedimentary rock

Sylacauga Marble Group; Fayetteville Phyllite (Cambrian?-Ordovician?) at surface, covers < 0.1 % of this area

Fayetteville Phyllite - dusky-red and medium-gray phyllite and slate interlayered with light-brown to light-gray feldspathic metasiltstone, fine-grained metasandstone and dolomite marble.

Lithology: phyllite; slate; metasedimentary rock; marble

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

Kahatchee Mountain Group; Kalona Quartzite Member of Wash Creek Slate (Precambrian?-Cambrian?) at surface, covers 2 % of this area

Kalona Quartzite Member of Wash Creek Slate - light-brown to light-gray coarse-grained, feldspathic quartzite and metaconglomerate in lower part of Wash Creek Slate.

Lithology: quartzite; meta-conglomerate

Parkwood Formation and Floyd Shale undifferentiated (Pennsylvanian-Mississippian) at surface, covers 0.8 % of this area

Parkwood Formation and Floyd Shale undifferentiated - Parkwood Formation -- Interbedded medium to dark-gray shale and light to medium-gray sandstone; locally contains dusky-red and grayish-green mudstone, argillaceous limestone, and clayey coal. Floyd Shale -- Dark-gray shale, sideritic in part; thin beds of sandstone, limestone and chert are locally present; beds of partly bioclastic, partly argillaceous limestone are abundant in parts of Calhoun and Cherokee Counties.

Lithology: shale; sandstone; mudstone; limestone; chert; mixed clastic/coal; clay or mud

Talladega Group; Lay Dam Formation (Silurian?-Devonian) at surface, covers 7 % of this area

Lay Dam Formation (Talladega Group) - interbedded dark-green phyllite, medium-gray to light-brown and black metasiltstone, dark-green feldspathic metagraywacke, and light-gray and dark-gray medium to coarse-grained arkosic quartzite and metaconglomerate; graphitic phyllite common in upper part. In Cleburne and Calhoun Counties, rocks mapped as the Lay Dam include the Abel Gap Formation of Bearce (1973) and consist of interbedded greenish-gray metasiltstone and quartzite, black phyllitic metasiltstone, medium-gray to greenish-gray arkosic quartzite, and dark-gray pyritic quartzite. In Clay Chounty the upper part of the Lay Dam includes black graphitic sericite phyllite and slate reportedly containing plant fossils (Erin Slate Member).

Lithology: phyllite; metasedimentary rock; quartzite; slate; meta-conglomerate

Ultramafic rock (Precambrian to Paleozoic) at surface, covers < 0.1 % of this area

Ultramafic rock - ultramafic pods and sheets, principally enstatite-hypersthene pyroxenite with hornblende and actinolite alteration assemblages.

Lithology: pyroxenite

Elkahatchee Quartz Diorite Gneiss (Precambrian to Paleozoic) at surface, covers 21 % of this area

Elkahatchee Quartz Diorite Gneiss - mesocratic to melanocratic, fine to coarse-grained, massive to strongly foliated, locally sheared quartz diorite gneiss.

Lithology: orthogneiss