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1200-900 MYA: Greenville orogeny forms 1st super-continent: Rodinia
Proterozoic->Meso-proterozoic.
Rocks were deformed in a massive continental collision known as the Greenville Orogeny. Rodinia, the first super-continent, is the result. The piece of crust that would become the Carolinas was shoved against South American crust. This crumpled and thickened crust, burying it under 20,000 ft. tall mountains! -
750-680 MYA: Rodinia rifts apart; first attempt to split fails.
Proterozoic->Neo-proterozoic.
As rodinia begins to rift, rift-basins without vegetation form. Rivers fill these valleys with sediment and you can see this present at Grandfather mtn. Basaltic magma came piping through the widening cracks, cutting rift sediment and crust. However, for some strange reason, Rodinia's first attempt to split falters, and the super-continent lives on. -
620 MYA: Rodinia's 2nd attempt to rift is a success.
Proterozoic->Neo-proterozoic.
The magma along with granitic magma injection is a process called bimodal magmatism (producing both basalt and granite.) This pulse of bimodal magmatism was enough to finally put into motion the rifitng and permanent extinction of Rodinia. -
620 MYA: While Rodinia splits, Iapetus Ocean forms.
Proterozoic->Neo-proterozoic.
Ancient beach sands are preserved scattered throughout the Carolinas. A mid-ocean ridge churned out oceanic crust in the middle of the Iapetus, slowly widening the gulf in between the two main parts of Rodinia-Laurentia & Gondwana. As it widened. the Carolinas were pushed away from the edge by new crust and became geologically quiet. -
700-600 MYA: Earth is shifitng from snowball earth to greenhouse warming.
Proterozoic->Neo-proterozoic.
There is glacial sediment from this time visible in Valle Crucis, North Carolina. It's exposed and shows the times where glaciers have frozen and scraped sediment along with them, and then melted and released this sediment. Very cool! -
500 MYA: New subduction zones bring Gondwana and Laurentia together.
Phanerozoic->Paleozoic->Cambrian.
Offshore from Laurentia was a sliver of crust, oceanic crust subducted under this which caused a line of active volcanoes to erupt on this piece of crust. The ocean had an active convergent boundary, and the fragment was moving toward the Carolinas, scraping oceanic floor and basaltic crust with it. We can now see this basaltic crust and oceanic floor preserved along the coastline of North Carolina! -
460 MYA: Crust fragment collision forms tall Appalachians ~15,000 ft.
Phanerozoic->Palezoic->Ordovician.
The edge of crust of the Carolinas was shoved beneath the wedge and the fragment and became a permanent part of the Carolinas. Today, it is known as the Piedmont Terrane. The force of the collision formed the ancestral applachians! (~15,000 ft.) -
420-370 MYA: Acadian orogeny forms huge mountains due to Gondwanan fragment collision.
Phanerozoic->Palezoic->Devonian.
The Acadian orogeny, the major mountain building event, produced many features. The thickened crust of the mountains produces metamorphism in the deeper rocks, which we can observe today. If the crust is thick enough, the deepest rocks melt and can form igneous rock, which we can observe. Thrust faults and clastic wedges are also present at these major mountain building events, like the thrust fault present underneath the Blue Ridge mountains! -
330 MYA: Gondwana collides with Laurentia: pushes Applachians to ~26,000 feet!
Phanerozoic->Paleozoic->Carboniferous.
This collision, the Alleghainian orogeny, was the last great upheaval of the Carolinian crust. Stone mountain and Mt. Airy were created durong this collision. When the orogeny was complete, the continents assembled into Pangaea. What a HUGE collision! -
330 MYA: Pangaea forms due to the Alleghanian orogeny.
Phanerozoic->Paleozoic->Carboniferous.
Just like with Rodinia, the crust cracked and sank as it stretched apaprt. Rift valleys formed, and there, basins continued to form the Atlantic Ocean. Pangaea is now alive and well! She will continue to be so for another 100 million years or so as well. -
220 MYA: Pangaea begins to rift, forming NC's two triassic basins.
Phanerozoic->Mesozoic->Triassic
Rift basins formed up and down the east coast and almost 4,000 miles of oceanic crust was created by the divergent plate boundary in the middle of the Atlantic Ocean. North Carolina's two triassic basins, the Deep River basin and the Dan River basin, were both formed during the rifting of Pangaea and are visible today. -
220-90 MYA: Quiet and continuous geological change froms barrier islands and beaches.
Phanerozoic->Mesozoic->Cretaceous.
Erosion has widdled the Applachain peaks, rivers formed sandy beaches, off shore barrier islands, and a sediment-draped continental shelf. Rivers carried the sediment eroded off the Applachian peaks to the end of their road and thus formed the above landforms. -
90 MYA: Sea levels reach 800 feet higher than today's; highest in 600 MY.
Phanerozoic->Mesozoic->Cretaceous.
The rising of this sea-level may have attributed to the steep change in elevation from the Piedmont to Blue Ridge. The cause can be attributed to the beautiful and ever-becoming rare glaciers! They melted due to a time in the Earth's history in which the Earth heated up excessive to normal called greenhouse warming. This allowed for much more water than normal to be present withn Earth oceans/seas/rivers/etc. -
2 MYA: Orangeburg Scarp shows ancient shoreline of 270-ft. rise in sea level.
Phanerozoic->Cenozoic->Neogene.
The Orangeburg scarp is a big geological sight because it shows how quickly Earth can heat up and freeze up and change the geological appearance of certain areas forever. You can find fossils of seashells and other orgasims buried high in mountains simply because the seal level was once that high! How cool is that?! -
125,000 YRSAGO: Sea-level is 20-ft. higher than today!
Phanerozoic->Cenozoic->Neogene.
The suffolk scarp records 20-ft. rise in sea-level in only the past 125,000 years. Again, 20-ft. seems like nothing compared to the once 600-ft. rise in sea-level, however, this is quite a massive amount more water world wide. Consider how massive the ceans are today, then add another 20-ft. of water EVERYWHERE, you have got a massive amount of water! Now, though, the water that was once in the oceans is now frozen as difficult-attainable fresh-water glaciers. -
10-20 MYITF: Oceanic crust will sink: active convergent boundary will form.
Era-Eon-Period Unknown.
Volcanoes, earthquakes, and a new mountain ridge will form when this boundary forms. Roads will become sanded over, beach houses may tumble toward the surf. We could, very easily, have brand new geography along the entire east coast in only 10-20 million years. Sadly, however, none of us will be around to witness it. :(
