Transcript oldest rocks

NC Geological History
Bubble Map
• You need to make a bubble map using the
information provided about North Carolina’s
geological history.
• Be sure to include all major events *
• Put the notes in your own words.
• Orange-written away from map
• Red- written Coastal region
• Green- written in Piedmont region
• Purple-written in Mt. region
Earth
• Formed 4.6 billion years ago
• The landmass under North Carolina began to
form about 1,700 million years ago, and has
been in constant change ever since.
Science Daily
NC Geological History
Continents broke apart, merged, then drifted
apart again. As landmasses came together, the
Appalachian mountains (and other mountain
ranges on the earth) were formed — and wind
and water immediately began to wear them
down by erosion.
NC Geological History
• After North Carolina found its present
place on the eastern coast of North
America
• The global climate warmed and cooled
many times, melting and re-freezing the
polar ice caps and causing the seas to
rise and fell, covering and uncovering the
Coastal Plain.
Piedmont
Coastal
Ncpedia.com
NC Geological History
The first humans arrived in North Carolina
just 10,000 years ago — and continued the
process of environmental change through
hunting, agriculture, and eventually
development.
Coastal Region
Coastal
*Flat area underlaid by young, unconsolidated
sediments produced by erosion of the
“Appalachian Mountains and deposited here
*In the Coastal Plain in the east, younger
sediments are found (Tertiary, 65 to 2 million years
and Quaternary, less than 2 m.y.).
*The Coastal Plain is home to hundreds, perhaps
thousands, of the mysterious oval basins called
Carolina bays.
Barrier Islands
*Formed by sand deposits by currents and rising
seas
*The Coastal Plain of NC was underwater, but the
ocean began to recede later in the Cretaceous Era
eventually allowing the Outer-Coastal Plain to
appear and be above sea level 65.5 Mya: Palocene
*Also, due to the glaciers receding a ridge was left
above sea level, which was the Barrier Islands 1.8
Mya: Pleistocene
www.thinkingdrinking.com
Piedmont Region
Piedmont
*Area of rolling hills underlain by mostly ancient igneous and
metamorphic rock and igneous rocks are the roots of the
volcanoes formed during an ancient episode of subduction
that occurred before the formation of the “Appalachian
Mountains
*Between the Blue Ridge and Coastal Plain is a complex set of
mostly metamorphosed, mostly Paleozoic rocks (550 to 200
m.y.) called the Piedmont.
*Granite, gneiss, schist and slate are the typical rocks here.
*North Carolina's famous gem mines and gold district,
America's first, are in the Piedmont. Exactly in the middle is a
former rift valley of Triassic age (200 to 180 m.y.)
Fall Zone
• Sand Hills formed due to erosion carrying
sediment to the "Coastal Plains." Eventually,
heavy clay sinks downward causing sands that
form dunes due to the wind. Most likely when
the Fall Zone formed. Due to heavier rocks
becoming more soft 1.8 Mya: Pleistocene
Eoearth.org
Mountain Region
Appalachian Mountains
*The rocks at the core of the Appalachian
Mountains formed more than a billion
years ago.
*At that time, all of the continents were
joined together in a single supercontinent
surrounded by a single ocean.
*We can see fragments of the billion-year
old supercontinent at the surface in many
places in the Appalachian Mountains.
Ridges/Valleys
*Area with long parallel ridges and valleys
underlain by ancient folded and faulted
sedimentary rocks
*Folding and faulting of the rocks occurred
during the collision between “Africa and North
“America
* Collision occurred during the late Paleozoic Era
and produced the “Appalachian Mountains
Blue Ridge
*High ridge separating the Piedmont from the
Valley and Ridge Province
*billion-year old igneous and metamorphic rocks
are the oldest in NC
*By the end of the Mesozoic era, the Appalachians
had been eroded to an almost flat plain.
*It was not until the region was uplifted during the
Cenozoic Era that the distinctive present
topography formed.
https://www.youtube.com/watch?v=EpC31JbMY-A
https://www.youtube.com/watch?v=cSnrFld3EE8
https://www.youtube.com/watch?v=H72I_kVFbJM
https://www.youtube.com/watch?v=VeNlAIndO7s
https://www.youtube.com/watch?v=NE_tDjhNwfA
*North Carolina's oldest rocks are the
metamorphic rocks of the Blue Ridge belt in the
west, cut off abruptly at the Brevard Fault Zone.
They are strongly altered by several episodes of
folding and disruption. This region yields some
industrial minerals.
Fineartamerica.com
River Basins
• Land drained by rivers
• Most rivers and river basins were most likely
formed during this era due to glaciers fully
receding inland. 5.3 Mya Pilocene
NC Fossils
• Fossilized remains of animal and plant life
have been discovered at numerous locations
in North Carolina
• Primarily in the sedimentary rock formations
of the eastern coastal plains
• -NC major rock and mineral resources:
limestone (concrete), coal (energy), gravel and
crushed stone (road construction)