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.
2. NC GEOLOGY
VOCABULARY:
province Coastal Plains
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- area of 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 LAND AREA:
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
8. RODINIA breaks up
700 mya
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
10. • 500mya Paleozoic Era, 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 wore down 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
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13. 13
• warm, swampy climate allowed much plant
growth on Pangea:
• increase in photosynthesis added much
oxygen to the atmosphere
• extra oxygen allowed for enormous
14. 14
• huge forests of 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 climate changed, 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 is not 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)
18. • Mesozoic Era 245 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 rifts were formed and filled with
boulders, cobbles, sand, silt, & clay: turned into the
reddish sandstones, siltstones, shale & of mudstones
today
19
22. • By the end 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
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26. NC’s modern geology determined 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 M O 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
29. P I E D 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
31. C O A S 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
34. T h e F 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 Population Centers:
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
37. O U T E 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
40. 40
Headland- regions that project into the ocean:
EROSION
Bay- indentations in the shoreline
DEPOSITION
Bathymetry
- contour of
ocean floor
HEADLAND
BAY
41. 41
Longshore current ocean current that moves
parallel to shore.
Creates:
• beach drift (zig-zag pattern)
• spits
42. 42
Spit
• Sand deposit connected 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
47. Groin (groyne)
• Man-made, rigid hydraulic structure built along
an ocean shore
• Slows down the longshore current, dropping
sand & building up shoreline
47