My head spins when I listen to Stan Riggs and Orrin Pilkey. They are legendary geologists. Both have been studying coastal N.C. for more than half a century. Last week I spent a couple days with the two of them on Ocracoke Island and Portsmouth Island.
When I listen to them, my whole sense of time changes. History to them is a whole other thing.
They look at the state’s coastal plain and what they see is a quarry near the small town of Fountain, in Pitt County. The quarry’s rock is the same rock that you’d find in Dakar, Senegal, a relic of a time more than 200 million years ago when what’s now eastern N.C. and what’s now West Africa nuzzled together.
That was before the land broke up and the continents separated and formed the Triassic Basins—the birth of the Atlantic Ocean.
Pilkey, now 83, and Riggs, now 79, described the edge of N.C.’s continental shelf, the plateau offshore that runs out to sea and then drops precipitously into the deep ocean. There, they told me, you’ll find 40,000 feet of sediments.
In those sediments you can find traces of many ecological worlds, once here, now vanished. Plumb those sediments and you see them: layer upon layer—tropical coral reefs, salt pans, big deltas, drowned river estuaries, ancient beaches.
They also told me: those sediments are what’s left of the Appalachian mountains, back when they were among the world’s greatest mountain ranges, like the Himalayans or the Andes today.
They conjured up images of ice ages, come and gone. In the most recent ice age, we would not have recognized eastern N.C.: it was a semi-arid land, one covered with boreal forests, spruce and fir trees, more closely resembling the Canadian north than what is here now.
It was also an age of big storms. We can see evidence of them in our braided rivers bottoms, shaped by those storms’ wild cataracts and sprawling floodwaters into twisting strands and narrow offshoots.
Then the two geologists described the slow unfolding of a landscape that we would recognize today.
The climate warmed up—that was 125,000 years ago. The sea moved inland, forming what’s called the Suffolk shoreline, an ancient beach that is roughly the path of U.S. Hwy. 17 now.
To the east of that shoreline laid a shallow continental shelf: shallow water, broad mud flats. On those flats, our great pocosin swamps formed as domes of organic matter accumulated over the centuries.
Some of those pocosin swamps covered hundreds of thousands of acres—the Great Dismal Swamp, Pocosin Lakes, the Croatan. They formed because water couldn’t flow off those ancient mud flats, and the clays below did not allow the water to drain, either.
Put a canoe paddle deep into Mill Tail Creek or the Northeast Prong of the Alligator River (as I often did when I was younger), they told me, and marvel at how such tiny, narrow creeks seem to have no bottom.
Pilkey and Riggs told me that those creeks (which local legend says have no bottoms) are the vestiges of another age. They are what’s left of ancient channels of great rivers, now gone or wholly transformed, that once moved toward the sea in paths that we would not recognize today.
I first studied with Pilkey and Riggs when I was an undergraduate at the Duke University Marine Laboratory more than 3 decades ago. Their coastal geology class was a series of frantic, almost madcap treks. We covered tremendous distances. We stopped at rock outcrops. We waded onto swamp hammocks. We stood in driving rain next to inlets that had burst open in the last hurricane. We slept in tents.
They never stopped talking—never ran out of things to tell us about the Earth’s history, never failed to demonstrate what this coastal world had come through and how it was shaped.
They also never ceased to caution us about the foolish things that humans have done to the Earth since about 1850. That was when, data shows, human beings first became as much a geologic force as earthquakes, volcanoes and the shifting of tectonic plates.
At one point this past weekend, Riggs and I were standing on the beach at Ocracoke Island, across from the pony pens. A group of public school teachers gathered around him.
Dig down into the mud beneath the sound waters behind the island, Riggs told them: you’ll discover the memory of old estuaries and river valleys, ancient oyster rocks and salt marshes. The beaches are moving, the sea is rising, everything is changing, he said.
* * *
On the ferry home, I found myself singing the greatest song ever written about geology and the human heart. It’s from the fabulous pop-noir band The Old Ceremony, led by N.C. singer/songwriter (and my friend) Django Haskins.