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Lithosphere 3 notes: NC Geology
The document summarizes the geology of North Carolina through time. It describes how North Carolina began with the ancient Appalachian mountains forming 480 million years ago during the collision of tectonic plates that built the supercontinent Pangea. Erosion of these mountains contributed sediment that was deposited in inland seas, forming the Coastal Plain regions. Changing sea levels over millions of years shaped the coastline, including the barrier islands along the Outer Banks. The geology of North Carolina was ultimately determined by plate tectonics and weathering processes acting over hundreds of millions of years.
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Lithosphere 3 notes: NC Geology
- 1. Lithosphere 3 NC Geology ppt.by Robin D. Seamon 1
- 2. NC GEOLOGY VOCABULARY: province CoastalPlains craton Carolina Slate Belt Rodinia Fall Line Pangea Coastal Plain Triassic Basin Barrier Islands Appalachian Mountains sounds Mt. Mitchell Piedmont Plateau monadnocks Piedmont Blue Ridge Mountains = Great Smoky Mountains 2
- 3. North America’s Origins Province- areaof ancient geological sameness; origin & history Craton- a large stable block of crust forming the nucleus of a continent We can’t go back in time, so scientists must be good observers, and put clues together to tell the story… 3
- 4. OLDEST NC LANDAREA: Appalachian Mountain Province CLUES • In these mountains today we see folded & thrust faulted marine sedimentary rocks, volcanic rocks, pieces of ancient ocean floor… • evidence suggests mountain formation from plate collision 480 mya… the building of Pangea; ancient Apps near the center RESOURCE: https://geomaps.wr.usgs.gov/parks/province/appalach.html 4
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- 8. RODINIA breaks up 700mya GONDWANA (China, India, Africa, S America, Antarctica) RODINIA forms 1.1 bya Laurentia + Baltic + Siberia LAURASIA EUROPE NORTH AMERICA Laurentia ASIA AFRICA S. AMERICA 8
- 9. 9 VIDEO: How NorthAmerica Got its Shape (5 min)
- 10. • 500mya PaleozoicEra, the area that would later be N America was at the equator, periodically submerged beneath the shallow ocean • layers of sediment & carbonate rock were deposited on the ocean bottom • Paleozoic Era; Ordovician Period (440-480mya) a neighboring oceanic plate subducted under the NA craton, building the first App Mtns • volcanoes grew; thrust faulting uplifted & changed old sedimentary rocks WHAT WE CAN DEDUCE… 10
- 11. • Erosion woredown the App Mtns, carrying sediments downstream • mountain building continued periodically for 250 million years as other continents melded into the growing Pangea supercontinent • 350mya (Carboniferous period) the Ancient African craton (Gondwana) crashed into Pangea, pushing up the Appalachians again • Climate was warm & wet … swamps RESOURCE: https://geomaps.wr.usgs.gov/parks/province/appalach.html RESOURCE: https://geomaps.wr.usgs.gov/parks/province/appalach.html RESOURCE: http://www.jamestown-ri.info/northern_appalachians.htm 11
- 12. Paleozoic Era; Carboniferous Period Paleozoic Era; DevonianPeriod Paleozoic Era; Permian Period SWAMPS: warm & wet: = high plant growth 12
- 13. 13 • warm, swampyclimate allowed much plant growth on Pangea: • increase in photosynthesis added much oxygen to the atmosphere • extra oxygen allowed for enormous
- 14. 14 • huge forestsof fern-like trees grew • lignin (tough-like bark) in the trees was not decomposed as decomposers had not evolved the ability to decompose it yet
- 15. 15 • As climatechanged, the forests died, leaving the un-decomposed trees to be buried • 50 million years of accumulated plant matter became buried • Pressure & heat turned it into… COAL fossil fuels: coal, oil, and natural gas from this time period that are mined for Energy + - lots of energy produced when it is burned Polluting & Non- renewable
- 16. 16 While NC isnot a coal-mining state, shale deposits from Chatham county are being considered for fracking hydraulic fracturing (fracking) fracking: a method of oil & natural gas extraction by injecting water, sand & chemicals into sedimentary shale rock VIDEO: What is fracking? (5 min)
- 17. 17 Where did thesedimentary shale rock come from?
- 18. • Mesozoic Era245 mya Pangea split, creating rift basins • Newark Rift System pulled North America from Africa, forming the Atlantic Ocean in between RESOURCE: https://deq.nc.gov/triassic-conglomerates-deep-river-triassic-basin-morrisville-nc18
- 19. NC’s Triassic Basin 200mya Smaller inland riftswere formed and filled with boulders, cobbles, sand, silt, & clay: turned into the reddish sandstones, siltstones, shale & of mudstones today 19
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- 22. • By theend of the Mesozoic, much of the old Appalachians were eroded away • Cenozoic Era, 50mya the area uplifted again, streams cut downward again forming mountain rivers & canyons on the ancient-formed landscape RESOURCE: https://geomaps.wr.usgs.gov/parks/province/appalach.html RESOURCE: https://geomaps.wr.usgs.gov/parks/province/appalach.html 22
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- 26. NC’s modern geologydetermined by plate tectonics & weather: - Appalachian Mountains - mountains were weathered and washed downhill into rivers, producing the materials that comprise the coastal plains - these sediments created beaches and barrier islands RESOURCE: https://www.ncpedia.org/geology 26
- 27. N C MO U N T A I N S oldest • Blue Ridge Mountains- part of N America’s Appalachian Mtn chain • ROCKS: igneous, metamorphic, & sedimentary • 43 peaks of 6,000 ft • Mt Mitchell 6,684 ft • RESOURCES Mining: deposits of feldspar, mica, raw materials 27
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- 29. P I ED M O N T • Piedmont Plateau- stretches from Alabama to New Jersey (includes NC) • ROCKS: metamorphic, igneous rocks • landscape worn down to hills • some isolated hard rock outcroppings remain- monadnocks- Pilot Mountain, Uwharries • Carolina Slate Belt- evidence of ancient rift zone • RESOURCES Mining: gneiss, schist, lithium, clay, sand, gravel, building stone, gold 29
- 30. 30 Pilot Mountain, MtAiry NC
- 31. C O AS T A L P L A I N largest region • During Mesozoic era, the coastal plain was a wide sloping region well above sea level • loose soil eroded & deposited at the ocean forming beaches • During Cenozoic era, ocean covered then receded across the NC Coastal Plain region repeatedly; made terraces • RESOURCES: sand- used for glass-making Mining: clay, limestone, phosphates 31
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- 34. T h eF A L L L I N E • Fall Line: line of erosion between the Piedmont and Coastal Plain regions; hard rocks sink into softer, eastern rocks • in rivers this creates natural falls & rapids; (places to port) • influenced NC transportation, settlement, population distribution, and economic development • today, scientists look at fall lines to determine pollution effects on either side of the line 34
- 35. Fall Line PopulationCenters: Tar River: Tarboro, Greenville, Rocky Mount Neuse River: Kinston, Smithfield, Goldsboro Roanoke River: Weldon Eno River: Hillsborough Alamance Creek: Alamance Fall Line parallels I-95 N/S 35
- 36. 36 Great Falls, PotomacRiver: hard metamorphic Piedmont Rock
- 37. O U TE R B A N K S • chain of barrier islands 175 miles long; • sounds separate mainland from the Outer banks: 30 miles • Pamlico Sound- largest NC sound • Albemarle Sound- 2nd largest • topography constantly changing due to erosion & deposition: beaches widen & narrow; inlets close & open up • RESOURCES: drill exploration for oil on the East Coast currently (2018) buffer the islands by 50 miles 37
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- 39. 39 Beach-Waves continually movesand on coastline Shorelines influenced by: • waves • tides • surface currents crest crest wavelength wave break Wave “feels” the bottom (slows down)
- 40. 40 Headland- regions thatproject into the ocean: EROSION Bay- indentations in the shoreline DEPOSITION Bathymetry - contour of ocean floor HEADLAND BAY
- 41. 41 Longshore current oceancurrent that moves parallel to shore. Creates: • beach drift (zig-zag pattern) • spits
- 42. 42 Spit • Sand depositconnected to land, extends into water Tombolo • Spit with a hook-like end These features can form: Barrier Islands • Long linear Islands of sand that are deposited by waves parallel to shore; few km wide • First line of defense during powerful storms
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- 46. 46 Lighthouses- Used to navigateships in the dark to warn them of the shallow waters & to indicate shoreline
- 47. Groin (groyne) • Man-made,rigid hydraulic structure built along an ocean shore • Slows down the longshore current, dropping sand & building up shoreline 47
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- 49. 49 NC Geology LAB 1.Video 2. Labsheet: • Minerals of NC • NC Geology 3. Resources Page
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