Georgia Geology Notes 4 Provinces

1. Georgia Geology Notes � 4 Provinces

3. Valley & Ridge Province � (incl. Appalachian Plateau) Cambrian � Pennsylvanian folded & faulted sedimentary rocks (544 to 286 m.y.) Fracture and karst aquifers Bounded by Cartersville and Great Smoky Mt. faults Alternating anticlines & synclines, thrust faults Cambrian � Ordovician sediments deposited on passive margin. Limestones, shales, sandstones. Ordovician � Pennsylvanian � mostly clastics derived from rising highlands. Sandstones, shales, coal (Pennsylvanian Period)

4. Taconic Orogeny �collision of Island Arc & Laurentia continent uplifted mountain range �Taconic Highlands�. Erosion of highlands produced a series of northwestward prograding �clastic wedges� (river deltas). Later orogenies rejunvenated uplands.

5. Georgia Geology Notes

6. Blue Ridge Province � Precambrian � Devonian(?) igneous and metamorphic rocks � includes phyllites, schists, gneisses, metabasalts, other metavolcanics, marble, quartzite Fracture aquifers, except for a few karst aquifers � Murphy Syncline Highest topography in Georgia � 28 peaks > 4,000 ft.

9. Appalachian Mountains � a quick summary Late Precambrian (600 m.y.) � Rifting of super- continent, opening of Iapetus Ocean. Late Ordovician (450 my.) � Island arc collision with North America � Taconic Orogen y Clastic wedges accumulate NW of Taconic Highlands. Late Devonian (410 to 380 m.y.) � Collision of Baltica and North America � Acadian Orogeny Late Pennsylvanian (320 m.y.) � Collision of N.A. with Africa, final deformation & uplift. Stone Mt. and other granites emplaced � 300 m.y..

10. Fall Line � separates crystalline rocks of Piedmont from present extent of softer sediments of Coastal Plain. Fall Line Cities � Columbus, Macon, Augusta Marked by waterfalls and rapids. Piedmont may have been partially covered by Eocene and Oligocene transgressions (sea level rises). Shoreline may have been low ridge of Brevard Fault Zone. Evidence eroded away.

11. Coastal Plain Province � Late Cretaceous to Holocene (Recent) deposits at shoreline. Age � 70 m.y. - >10,000 yr. Layered sediments, sands, clays, limestones. Late Cretaceous sediments � mostly deltaic, including Providence Sand. Paleocene � Oligocene sediments � mostly marine. Miocene � Holocene � mostly continental deltaic, fluvial and alluvial sediments, except near coast. Aquifers � uniform sediments, a few karst wells.

13. Resources Valley & Ridge Province Oil & Natural gas (other states), Coal, Limestone, Barite. Blue Ridge Province Marble, minerals in pegmatites, Gold, Sulfide minerals (including Copper), Talc, Corundum. Piedmont Province Granite, minor Gold, Copper, Feldspar, minerals in pegmatites, minor Marble. Coastal Plain Limestone, Kaolin, Bauxite, Sand.

14. Review Valley and Ridge Province Hard, compacted Paleozoic sedimentary rocks, folded and faulted during uplift of Appalachian Mts. Blue Ridge Province Hard, Precambrian to Paleozoic metamorphic rocks, folded, faulted, and metamorphosed during uplift of Appalachian Mts. Piedmont Province Hard, Precambrian to Paleozoic metamorphic and igneous rocks, similar to Blue Ridge Province. Coastal Plain Province Soft, uncompacted Late Cretaceous through Cenozoic sediments, layers inclined gently toward Atlantic Ocean and Gulf of Mexico (SW Ga.)

15. Groundwater Resources Valley & Ridge Province � Fracture zones, karst features (caverns, enlarged fractures) Blue Ridge Province � Fracture zones, karst features (in Marble) Piedmont Province � Fracture zones Coastal Plain Province � More uniform aquifers (softer sand, limestone, karst features � Regional Floridan aquifer � Georgia and Florida.

16. Geology and Ecology Geologic structures affect topography and stream channel distribution Rock types influence soil type Soil type influences nature of rainfall infiltration Soil type and topography influence vegetation types Hardness of rock influences type of porosity and permeability and aquifer types Topography influences climate and microclimate Rock type influences chemistry and pathways of ground water