Geology Rocks!

Dinner warming up, with mist adding
mystery to the campsite.

Now, in theory I'm a physics student, but the rest of the time I persistently wonder why I haven't chosen to study philosophy or run off to work in one of the National Parks, until I realise that I can't see myself living without science. Recently, however, all of these uncertainties have taken a new direction. I want to see the great outdoors, with one arm brandishing a notebook and with the other a handlens, chasing down Earth's mysteries, wild and free. I want to be a geologist.

So, to cut a long story short, last Thursday evening I found myself pulling out my hiking bag and packing in my tent and a lot of pencils in preparation for the fieldwork part of Introduction to Geology.

We drove to upstate New York, pitched our tents in the drizzle, ate soup and s'mores around the campfire, and got ready to go hunting fault lines across the state.

Looking upstream on the Canajoharie Gorge - you can
see how beautifully the water cuts across the shale.
Thanks to Matthew Joss for the photos.

One of my favorite sites was a steep gorge in the Canajoharie River. We were on a bed of shallow water, with a twenty metre cliff of shale towering above us - the kind of thing that would look like a rock climber's paradise were it not possible to break the layers of rock between your fingers. Shale is usually laid down in deep water, and a lot of people managed to find fossils of trilobites.
However, these particular walls had rusty patches seeping out between a few of the layers - one of them ended right at the level of the river bed, and tracing it along I found a gap, where between two layers of shale was nothing but ash. Volcanic ash. It crumbled when I poked it. An inch thick even after being crushed under so many tons of rock. Between two layers of mud landing on the sea floor, a volcanic eruption had taken place, spewing ash across what is now the peaceful, earthquake-free Eastern US. Estimating the age from the trilobites in the layers above it, I got to spend my Saturday morning poking 400 million year old volcanic ash.