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| The Basin and Range from 20,000 feet. (Photo by me.) |
It occurred to me while flying somewhere over the Basin and Range, that I haven't posted many blogs about my given field of study. I decided then, as we sailed over dry lake beds and faulted earth that I would re-read Basin and Range by John McPhee and write about my favorite geological province. McPhee's is an older book, first written in 1980 I think, but one of the best in expressing the wonder of geologyof the western US.
He makes fun of the names and terminology while trying to explain them, paints vivid pictures of landscapes long gone, and explains the history of geology and it's methods without boring the reader to death. It's really a great read, and I highly recommend it to anyone who has even the slightest curiosity about how geology works, and why it's so interesting.
I also though it was a good time to post something about geology because of the earthquake that occurred off the coast of Japan a couple days ago, that caused the tsunami that devastated much of northern Japan.
It seems to me anyway that most people have a general knowledge about other sciences namely ones that affect them directly. Take biology for example, most people know that we have DNA and genes that explain things like hereditary disease. Or astronomy, that the sun is the center of our solar system, and the length of the day is decided by the spin of the earth. Meteorology is another science that the average Joe knows something about.
But geology, because it's implications are so non-important to the live of the average person (except maybe here in California), has almost no identifiable base of understanding in popular society. If I speak about rock less that 10,000,000 year old as being "young" or oceans that existed two hundred million years ago people look at me like I am crazy. When I explain that the San Andreas fault is the boundary between two tectonic plates moving in different directions people are amazed. When I say something to the effect that one would never (under any circumstance known on earth) find fossils of dinosaurs in granite, I get doubtful glances, and questions like "How could you know that? You haven't seen every rock on the planet. I'm sure there is a granite
somewhere with a Tyrannosaurus bone in it." There is no solid base for which a lay person can even begin to construct the rational geologist use to make their discoveries, establish their facts, or see the world as it existed at a time when there were no humans around to see it.
It's too bad too because I can tell you from personal experience the paradigm that comes from viewing of the earth as a geologist is one of the most rewarding and exhilarating feelings I have ever had as a scientist.
I am not sure how many people (over the age of 5 anyway) still look out the window of an airplane as it flies thousands of feet above the earth, but I do. Always. Unless there are clouds or it's dark, my eyes are glued to the terrain below. Viewed only as shapes and colors the surface of the earth is breathtaking. But looking at jagged mountains, iron stained valleys, ribbons of bedrock that appear to have been cut and pulled apart by a giant pair of scissors, ridges tilted upward to the sky and halved by rivers that curl almost back on themselves, the red of oxidized sandstone and the black of basalt flows out of small cinder cone volcanoes, and understanding the processes that made it all is just...mind blowing.
I can look out the window and see continents colliding, mountains growing, racing toward the sky, the earth being stretch and pulled apart, tiny volcanoes erupting like black pimples across smooth gray-tan sediments of bowl shaped valleys. I see oceans where there are now deserts, I see sand dunes where there are now mountains. I see what was once millions of years of quiet marine strata, violently split apart and jostled into near vertical positions. Not only can I see these events, I can also tell the order in which they occurred (although not the specific time in years.) Take this example from McPhee where he was discussing a road cut along the highway
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In order to account for that hillside...you had to build a mountain range, destroy it, and then build another mountain range in the same place, and then for the most part destroy them."
One of the greatest qualities a geologist possesses is the ability to see what is no longer there.
If I see low smooth mountains with exposed strata flanked by a shallow valley dotted with cinder cone volcanoes and tiny roads cutting through the dark basalt I can piece together a story with a beginning middle and end. It will probably span a hundred million years and go something like this:
Way back when, there was an ocean that over millions of years deposited sediment horizontally on its bottom where it hardened into rock. Then something occurred, (maybe colliding plates, maybe a pulling apart of the earths crust...who knows?) that caused the ocean to disappear, and several large lakes to form between the exposed layers rock that were broken apart into fresh sharp pieces and tilted this way and that. Then over another long time time the sharp ridges were dulled by wind erosion and rain. As the valley filled and the lakes evaporated, the mountains became low islands in a sea of sediment. Sometime later the earth was stretched (ah ha! so the mountains formed by stretching, not by collision!) a little more, became thinner and small basaltic (the kind in Hawaii that get their "juice" from the molten material under the rigid crust) cinder cone volcanoes squirted through the weak areas, where the crust of the earth was thinnest, and where the magma below was closest to the surface. Then later on (probably a few million years) human beings came across the mountains turned to hills with bulldozers and concrete and blasted a road through the extinct volcanoes, and over the gently sloping hills and valleys to connect the dozens of small desert towns that lay scattered across the landscape. The end.
It may seem unlikely that a person could tell all of that by looking out the window at a bunch of mountains, but when you understand the principles of geology, it is obvious in the rock, in the topography that the story I just told you (more or less anyway) is exactly how the Basin and Range formed, over several million years.
John McPhee describes the Basin and Range as "
a soundless immensity with mountains in it" and in those silent mountains is a story which only geologist hear and appreciate. If I could impart any aspect of geology to the non-geologist it would be the ability to look at a mountain, or a layer of stratified rock and be able to read the story in it. That's what makes geology cool. It's finding clues in outcrops of rock, and knowing how to extrapolate back from the piece of siltstone in your hand to the bottom of the ocean it formed in several million years ago. McPhee says it perfectly by saying
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Geologist...inhabit scenes that no one ever saw...scenes gone and gone again....including seas, mountains, rivers and forests...and archipelagos of aching beauty...If some fragment has remained in the crust [of the earth] somewhere and something has lifted that fragment into view, the geologist in his tweed cap goes out with his hammer and his sandwich, his magnifying glass and his imagination, and rebuilds the archipelago."
I can look out the window and see continents colliding, mountains growing, racing toward the sky, the earth being stretch and pulled apart, tiny volcanoes erupting like black pimples across smooth gray-tan sediments of bowl shaped valleys. I see oceans where there are now deserts, I see sand dunes where there are now mountains. I see what was once millions of years of quiet marine strata, violently split apart and jostled into near vertical positions. Not only can I see these events, I can also tell the order in which they occurred (although not the specific time in years.) Take this example from McPhee where he was discussing a road cut along the highway
