The story of North Carolina’s geologic past begins over a billion years ago. Yep, that was BILLION, with a “B,” and the number is actually closer to 1.8 billion years.
In western North Carolina, where the current Appalachain Mountains stand, there has been an endless cycle of mountain growth through uplift, followed by erosion and weathering. This has resulted in a mish-mesh of old mountain bits and pieces, over a billion years in the making. There are actually reports in some places, like Valle Crucis, that small parts of the original ancient mountain chain remain, poking through the earth as a few random boulders (aged 1.8 billion years), surrounded by younger rock, and covered by weeds. While it is something to be celebrated as our history, it might also be something to protect.
The geologic story in North Carolina, which is of course part of our natural history, came about because of the immense pressure and heat building inside the crust of the Earth as the continents shifted in the oceans for hundreds of millions of years. That heat melted rock in the crust, so that magma spewed to the surface between 800 and 500 million years ago, creating additional new land for our state.
Roughly 600 million years ago, much of the state was covered by an inland sea resulting in the fossil remains of marine animals that we can see in Linville Caverns, or the preserved ripples of water on an ancient shoreline at Pilot Mountain.
About 450 million years ago a chain of volcanic island arcs smashed into the eastern side of the state pushing up more mountains and leaving evidence of eruptions in places like Reed’s Gold Mine in Midland, NC with surprisingly large gold deposits that set off America’s first gold rush in 1799 after a young boy found a bowling ball-sized gold nugget in a stream.
Three hundred million years ago, as the continents were moving around within the oceans, our state was on the leading eastern edge of the continent when it pounded into current day Morocco during the formation of the giant supercontinent of Pangaea. Only one hundred million years later did Pangaea rip apart, separating North America (and North Carolina) from Africa. It was a violent land-shearing event, leaving three giant ditches in the middle of our state – the Triassic Basins.
Millions of years of erosion and weathering began washing away the insanely tall mountains in the western part of our state. Where did all of that rock go? Downhill. Massive rivers washed all of that rock across the region of the current Piedmont, filling in the three Triassic basins, and dumping the remaining rock, on the continental margin, like landfill, where the land met the newly formed Atlantic Ocean.
About 50 million years ago the Sandhills were formed. They were an area of coastline where rocks had been ground into fine sand. Winds blew the sand around fiercely until wiregrass settled, helping to hold the sand in place just long enough for an important species to take hold and spread efficiently in its newfound home- the longleaf pine.
Today, our coastline is comprised of rock and sand over 10,000 feet deep, moved from the tremendous ancient mountains to the current Coastal Plain by the magnificent Piedmont rivers in between.
Sometimes these concepts seem too large to even get our heads around, but part of exploring science and nature in our state means that we learn to make observations, we look at the evidence, and begin to piece together the story of how North Carolina came to be what it is today. How lucky are we to get to experience all of this natural history and learn about the fascinating geology of our state as it has developed over time.
