The Niobrara Sea

The Niobrara Sea

Science tells us that 85 million years ago, before The Great Ice Age came and froze vast amounts of water at the poles of our planet, the earth was a much warmer and wetter place. In fact, 85 million years ago, the great Niobrara Sea, also known as The Western Interior Seaway, completely covered what we know today as The Great Plains of the American Midwest.

Stretching from Utah through Iowa, during the Cretaceous Period, this inland sea stretched over North America all the way from the North Pole down to the equator, through the very center of the continent. All during the ‘Age of The Dinosaurs,’ the middle of North America lay as the muddy floor of a vast inland sea, submerged under water that was one or two football fields deep, for tens of millions of years.

Palm trees, cottonwoods, cedars, giant ferns, and flowering trees lined the fertile coasts and dotted the sporadic rocky islands. The Niobrara Sea was full of life. Colonies of Crinoids and Nautiloids, that looked like seashell-covered squids, swam in pulsating motions among vast shoals of fish. Herds of crabs ranged along the bottom of the sea, among the swaying reef-building coral, and around the pointy sea urchins, and there were occasional thick beds of various clams on the bottom, some of which grew to gargantuan size, measuring as much as three foot wide.

Up in the sky, there were 6 ft tall hairy winged birds that looked like giant bats with long sharp pointy beaks, named Pteranodons. They had wings as big as modern cars, and they soared above the teeming surface waters of the Niobrara Sea, hunting for fish.

Under the waves, the Niobrara Sea was even more dangerous. Huge sea monsters lived in those waters.

The Giant Squid - for example, haunted the waters of the Niobrara Sea. And there were others:

The Plesiosaur - which had a gigantic body as big as a city bus, topped by a long snake-like neck, with four extended paddle-like fins, swam these waters.

Xiphactinus - much bigger than a goldfish, at 15-20 ft long, was the largest bony fish ever, bigger than many modern bass boats. Xiphactinus had eyes the size of dinner plates, and a jaw full of big long spiky piranha teeth. A swimming school of those monsters would have been a terrifying sight.

Mosasaur - was a giant powerful swimming marine reptile. It grew to 15 tons and about 55 foot long, almost as big as an 18 wheeler truck and trailer. It had a big 6 foot long alligator face with a specially hinged jaw that could open over 3 foot wide, enough to swallow a man, with rows of thick powerful conical dinosaur teeth, each up to 3 – 4 inches long. The Mosasaur was fast and limber enough to rise up and catch flying sea birds, with a bite powerful enough to crush turtles and shellfish.

Cretoxyrhina - the 20 foot long giant 'Ginsu Shark'. With sharp serrated and thickly enameled teeth, this super predator apparently ate anything it wanted to eat, including the giant Xiphactinus, Giant Turtles, and even an occasional Mosasaur that crossed its path.

Although 85 million years ago is popularly thought of as ‘The Age of the Dinosaurs,’ people are sometimes surprised to learn that the term actually refers to something microscopic, and not something big like dinosaurs. The term ‘Cretaceous’ actually means ‘abounding in chalk’ and this is because, while those big dinosaurs were lumbering around on the dry land, at the same time, in the Niobrara Sea, there were thick clouds of billions of tiny one-celled golden brown algae floating in the warm waters. So much algae, that it may have created a very oxygen-rich environment necessary for dinosaurs to sustain their great size. These were ‘calcareous’ algae, with delicate calcium carbonate shells. When all those tiny microscopic plants would die, their protective shells slowly drifted down like a constant magical invisible snow that slowly built up on the sea floor, for tens of millions of years. In parts of the state of Kansas, the Niobrara Sea left chalk deposits that are 600 feet thick, very similar to the famous white cliffs of Dover, in England.

The neighboring state of Missouri, also under water for millions of years, got hundreds of feet of hard limestone deposits. Faults and water erosion have caused over 6,000 underground caves to form in the thick Missouri limestone deposits, making Missouri famous as “The Cave State.”

In other places, where the Niobrara Sea’s sandy beaches once existed, today there are deposits of sandstone.

Eventually, the Rocky Mountains rose up on the western shores of the Niobrara Sea, and after hundreds of feet of deposits had filled the basin floor, the Niobrara Sea completely receded, and eventually disappeared altogether into what we know today as the great grass-covered plains and farm lands of the American Midwest.

(c)

#history