BY HANNES THUM
One of the more defining characteristics of the study of geology is time. Big time. Deep time. Geologic time. We talk about the history of the planet and of the continents and the outcrops and the drifts and faults in terms of great spans of years such as periods and ages. Units of time that go so far beyond our human scales and human lifetimes that they simply cannot be adequately understood by our human minds (or at least by mine).
Eons, eras and epochs.
It seems hard to study geology at all without having to return again and again to this assumed concept that geology moves incredibly and imperceptibly slowly, but that there has been incredible amounts of time for it to occur. Amounts of time so vast that they, too, border on the imperceptible.
For many people, myself included, the most challenging piece of talking about geology is to stretch one’s brain out, slowly but surely, as if it were silly putty or a piece of chewing gum, and try one’s best to visualize what a few billion years looks like. Or even a million. Or even a thousand. The sound of water hissing against sandstone and cutting a river canyon, the immense but silent grind of fault lines, the welding of two continents together to make the highest mountains on Earth.
Like the invisibly measured drip, drip, drip of sap running down the outer bark of a whitebark pine perched on the lonely edge of a high alpine ridgeline. All of these years gone by.
I once visited a local whitebark pine that has been confirmed to be more than 700 years old, and I can barely get my head around that span of time, let alone the span of time that has built up and broken down that ridgeline numerous times in the four-and-a-half-billion years that our planet has been in existence. All of these years gone by.
It’s been said that the Atlantic Ocean is widening by a few centimeters a year; Everest grows a half a centimeter a year; that the Grand Canyon has been cut and eroded by only half a millimeter a year. You can hold these annual distances between your finger and your thumb. But can you hold that much time?
For as long as I can remember, I’ve believed that the study of geology required a leap of faith of sorts. That to understand how geology works, one had to deeply trust in deep time as a profound underlying force of geology, as powerful as plate tectonics, even though it was so hard to comprehend as to be nearly unprovable.
That one could turn coal into diamonds if one simply allowed time and heat and pressure to work their magic.
Hannes Thum is a Wood River Valley native and has spent most of his life exploring what our local ecosystems have to offer. He currently teaches science at Community School.