The town of Marietta, Ohio may have been founded in 1788 by pioneers wanting a permanent base northwest of the Ohio River Valley, but the land of Marietta has a rich past that stretches out long before that time, before even the Native American tribes that lived in the area.

The town that is now known as Marietta, Ohio has a rich geologic past, along with the area of Washington County and Ohio as well. I am hoping, with this blog post to introduce you to perhaps a small part of it.

DSCF1046A Warm, Balmy Sea…..

Now imagine if you can, traveling back to the end of the Cambrian period, about 488 million years ago. If you were to look out over the horizon that greets you in Marietta Ohio, you would be greeted by a vast shallow sea, and the air would be surprisingly dry. The sea would stretch as far as the eye could see and would be teeming with various types of marine life, including an explosion of different trilobite species. Over time, the waters will deposit sands, silts, and limy mud, along with various marine animals onto the bottom of the great sea.

Over time, that warm, shallow sea shifted and changed, becoming deeper in the east, with small muddy islands forming on the western horizon during the Ordovician period between 488-443 million years ago. The land and seas around the Marietta Ohio area also went under significant changes, including volcanic eruptions to the east, and the expansion of the seas to cover nearly the entire state of Ohio during the later portion of the period. However, you notice that the air is starting to become cold, and the great sea begins to retreat, feeding the glaciers that are starting to form to the south.


But eventually the seas return to the area, and the warm temperatures join them. The area of Marietta Ohio is south of the equator as it has been for some time, and various coral reefs serve as a home to abundant marine life, including clams, echinoderms, and brachiopods. Limestone is deposited over the previous sandstone and salt deposits that were in the area of Marietta Ohio at that time.

Giving Way to a Swampy Terrain….

IMG_6084Over time, the air around you become thick and heavy with the smell of stagnant water. The seas of eastern Ohio were cut off from fresh water at the end of the Devonian period, approximately 359 years ago. Sediments that are deposited during this period are organic-rich, black muds that were rich in uranium. Plants begin to come to life on the shorelines, and bony fishes and sharks begin to swim and hunt in the shallow seas.

A vast swamp forms throughout the area of Marietta Ohio and surrounding area, and life once again blooms and flourishes in the area, including land plants, amphibians, and various reptiles. Life in the swampy waters include crinoids, fishes, and brachiopods. This environment appears almost eternal lasting for about 100 million years.

A Land of Rivers, Lakes, and Ice…

file4911246896545By the end of the Permian time period, about 250 million years ago, the area of what is now called Washington County Ohio area was filled with sands and muds from various rivers and streams emptying into the swamp. The land around you slowly, very slowly begin to uplift and erode away, the land slowly rising and falling against the sea levels during the Mesozoic and Tertiary time periods. Chances are you see various dinosaurs and other land animals roaming the area and traveling against the horizons, but weathering and erosion erase the evidence of their passing over time.

By approximately 2.6 million years ago, thick sheets of ice are seen to the west and northwest of Marietta Ohio off in the distance, and over time, glacial waters and melt waters begin to slowly cut through the various sands, silts and limestone to form various valleys and hills, transforming the landscape. Eventually, you are joined in the Marietta Ohio area by various land animals including mastodons, mammoths, gigantic beavers. The plants begin to look more and more familiar to you, and eventually you see humans, like you traveling over the glacier areas toward your home, between 13,000 and 8000 BCE. The mighty Ohio River forms from the Allegheny and Monongahela rivers during this time, becoming one of the mightiest tributaries to the Mississippi River.

The area around Marietta Ohio and southeastern Ohio has undergone significant changes over the years, and not only during human habitation. The story of Marietta Ohio has included warm seas teeming with new life, swamps with rich organic black muds and stinking waters, rivers and streams, rolling hills, valleys, glacial meltwater deposits and raging rivers turning into serene landscapes.