I swear some people think they are the center of the universe but they couldn’t be because the universe carried on long before any human creature entered the stage.
So how do us humans know what happened on this planet before we got here?
Last week (June 2014), I had the pleasure of driving through the Rocky Mountains, from Denver to Grand Junction, Colorado, and beyond, into the Sierra Nevadas. The size alone of these landforms – the hills and the basins – are impressive but their various shapes, colors, textures, and striations are what make them so awe-inspiring.
Not only do those traits make the landscape of the western part of the United States interesting, they provide clues to geologists as to how this continent formed and who – or what – inhabited the space before the introduction of humanity.
Non-scientists like myself can appreciate the history of this land even with just the basic knowledge we obtained from 5th grade earth science class. Knowing a little bit about paleogeography (the study of ancient lands) simply makes the world around us more interesting.
On the other hand, geologists and other scientists with fancy-sounding titles are always looking for more clues and a richer understanding of the history of this planet. In fact, as
we returned to our car at one vista point in Utah that felt more like heaven than a pit stop, students from the University of Texas piled out of three large vans, notebooks and pens in hand, and ventured up the hill – their classroom for the hour. Thanks to the efforts of these researchers, we can get a glimpse into life on earth millions of years ago.
By studying the formations and characteristics of rocks and fossils found in those rocks, we can learn so much about the land, climate, and temperature way back when. We can tell if there was water, how deep it was, whether or not it was saltwater, and which way the currents flowed. Found bones, shells, footprints, and impressions made by leaves or other objects of nature provide more evidence of life before the human species came along.
The history of the North American continent is divided into three ages.
- 300 million years ago, we were in what is called The Coal Age, also referred to as the Pennsylvanian Period. The midwest where I live and what is now mostly farms, prairies, and urban areas was mostly low-lying and swampy with lots of fern trees.
During this period, coal beds formed in Illinois, Pennsylvania, West Virginia, Kentucky, and Tennessee. There were a lot of islands and shallow seas (salt water) in the middle of the continent. Over time, the accumulation of mud and lime, the deposition of rock and sediment, and the erosion of land created the mountain ranges that we see today, especially at the eastern and western ends of the continent. Life in North America during the Coal Age included algae, fungi, plants, and some animals – first with external skeletons and later those with internal vertebrae. At this time, almost all of the earth was formed into one big landmass. This supercontinent is referred to as Pangea (Greek for “all the earth”). About 200 million years ago, the continental drift began and North American started moving further and further away from what is now South American, Europe, and Africa.
- Dinosaurs began roaming the planet around 80 million years ago and so this time is referred to as The Age of Dinosaurs also known as the Cretaceous Period. At this
time, the Rockies were nothing like they look now and the Appalachian Mountains were much lower then. Much of California was under water and it was marine sediment filling a huge trough that ending up forming the mountain ranges we see today. Back then, the sea level was much higher than it is now.
- The Great Ice Age (Pleistocene time) began about 2 million years ago. Seems like yesterday! Much of Canada and the northern
section of what is now the United States were covered by a massive sheet of ice. Sea level was 450 feet below what it is now and the shape of the continent was somewhat different. For instance, Florida is currently smaller than it was back then.