Ohio’s Black Thumb

Ohio’s Black Thumb

When I first heard the term “fossil fuel” in grade school I was honestly intrigued and a little disturbed by the idea. I assumed one day, in the distant future, my dead, dry bones would be used as a power source. Thankfully, I was a little bit off on my assumption of what a fossil fuel actually is. As children we learn the impact these fuels had on Ohio’s history and will have on Ohio’s future. But back when I was a student the real questions that I wanted answers to were: Who were the faceless organisms that fossil fuels were made of? When did they live? What did they look like?

At its simplest, a fossil fuel is described as combustible organic material found buried underground. Things such as crude oil, coal, natural gas and heavy crude oils fall into this category. Coal is the most abundant fossil fuel found in Ohio.

Coal from the Ohio History Connection’s Education Collection taken from an unknown location in Ohio. The mining industry has played an important role in the state’s history.

Coal mining in the Southern and Eastern parts of the state began during the 1810s and 1820s. Early coal mining operations were small, but the arrival of the railroad, a rise in the use of steamships and the growth of industry in the years before, during and after the Civil War caused mining operations to grow in size and capacity. By 1872 Ohio mines produced more than five million tons of coal, and by 1886 those mines had doubled their production to about ten million tons. Today, coal still remains a large source of Ohio’s energy.

The history of coal in the Buckeye State does not begin and end with the coal industry, however. To discover the origins of this fuel you have to travel back in time by about 318 million years to a period known as the Pennsylvanian (318 million – 299 million years ago). During this time our state would have been unrecognizable to us.

At the start of the period, the growth of the young Appalachian Mountain range, caused by a much earlier collision of landmasses east of what would become modern day Ohio, sent an influx of sediment rushing into the state that pushed back the shallow prehistoric seas that had entered Ohio from the southwest. This dramatic event, coupled with periodic rising and falling ocean levels, which were probably caused by glaciation in the southern parts of the globe, meant that Ohio was actually a fluctuating coastal area during the Pennsylvanian. To top it off, the state also would have been located right around the equator, creating a very warm and hospitable environment for all kinds of animals and, importantly, the plants that would later become our coal.

Before you go and set your time machine for an ancient Ohio tropical vacation, though, I must warn you about a few things first.

The land during this period was actually very swampy along the coastal regions. The climate was also hot and humid. These conditions coupled with the extremely high amount of oxygen in the air made it possible for insects living in the swamps to become monstrous in size. Among the nightmarish giant insects were Meganeura, a carnivorous flying insect with wings over two feet across. Massive cockroaches and millipedes scuttled across the ground during this time as well. The swamps themselves were the reason why there was so much oxygen in the air that allowed insects to grow so large. These prehistoric coastal swamps are also the reason why Ohio has coal in its soil.

Meganeura resembled our modern day dragonflies, but this extinct insect is actually categorized with what are known as griffinflies. (Image: askabiologist.asu.edu)

The vegetation in those ancient swamps was very lush and very affective at producing oxygen. Plants familiar to us modern Ohioans, such as ferns, horsetails, conifers and giant reeds, grew during this time. But there were also plants that are far less familiar, such as the giant Lycopods. These plants are sometimes referred to as scale trees because of the scale shaped “scars” left on the trunk of the plant that were created after the strap shaped leaves became old and broke off. The Lycopods that grew during this period were some of the largest plants on Earth at the time. They commonly reached heights over 100 feet tall.

 Lycopods, such as this fossilized Lepidodendron on display at the Ohio History Center, are called scale trees because of their scale shaped leaf scars. Lycopods, however, are actually not trees at all! Instead they are closely related to modern day club mosses.  

Stigmaria (a generic title given to all Lycopod roots) currently on display at the Ohio History Center. Lycopods reproduced by spore pod rather than by seed and had an average life span of only 10-15 years.  

The extinct seed-bearing Alethopteris was an ancient Pennsylvanian plant that resembled our modern day ferns. This specimen is part of the Education Collection at the Ohio History Center. 

This rock contains the star shaped leaf pattern of Asterophylcites, a massive horsetail plant that lived alongside Lycopods and Alethopteris.

Sphenopteris is the name given to foliage of several different types of fern and seed fern that existed in the coal swamps of the Carboniferous. This particular specimen is part of the education collection at the Ohio History Center.  

Coal was formed when the ancient plants died and fell into the swamp water. Cut off from oxygen and regular decay those dead plants stacked on top of one another creating the perfect conditions to allow organic material to turn into peat. Many different factors, such as compaction and heat, needed to come together in order to make the peat turn into coal. The Pennsylvanian provided the perfect storm of organic material and the conditions to make fossil fuels.

The era of the coal-producing swamps of the Pennsylvanian Period came to an end when the climate became dryer around 299 million years ago, the swamps and its plants were soon replaced by the species and plants of the Permian Period (299 million– 251 million years ago). The Pennsylvanian Period lasted for a relatively short 18 million years, but the swamps and plant life of that time have greatly affected the course of Ohio’s history and continue to affect our future.

Posted February 1, 2018

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