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home again, home again
So. Home from Sedimentation and Stratigraphy field trip. Weather was about as good as could be reasonably expected, company was better, rocks were amazing. Have just showered off two days' worth of sweat and mud and rock dust. My pecs and thighs feel as if they was been pelted with large, weathered cleavage fragments of upper Devonian fossiliferous sandy shales from the Trimmers Rock formation. Which they weren't. Well, not on purpose. And I'm mildly sunburnt on my arms and face. And my feet hurt, and I have cuts and bruises all over. So I'm happy, if physically exhausted. More detailed trip report:
Saturday morning and afternoon: In which we drop some acid, and then have a very bad trip.
Because dropping acid is, of course, a vital activity for carbonate geologists such as Prof. Kaufman. He even requested that we bring our own; although none of us it, it not being particularly easy to acquire without connections, so we just borrowed his. (Yes, the bad geology puns continued all weekend. Aren't they gneiss?) I got everything else packed and ready: one pillowcase of tent and bedroll, one field pack of geology stuff, one backpack of miscellaneous other. I think I used everything in the field bag and nothing (other than the food) in the backpack.
I was the first one at the meeting place at 6:15 Saturday morning, even beating the professor, because he had locked his keycard and all the van keys in his office. So, yeah, we got off to a later start than planned. But all the junk and people fit in the vans-- the four girls and the female grad student claimed one van as the girls' van, so I spent most of the weekend in a confined space with Dory, Kim, Paula, and Kristina. We did the girl talk thing, too, boys and hair and clothes and gossip and music and sex and drinking and birth control and makeup and all-- and I actually found myself able to contribute most of the time, us all being geology students, after all. Girl talk is fun, once a month or so.
The first stop was at a farm in Fauquier County, Virgina. We traipsed by a stream, over barbed wire and past "Trespassers Will Be Shot" signs to an absolutely spectacular outcrop of neoproterozoic diamictite. (Neoproterozoic is right before the Cambrian, when the first fossils appeared. ~560 million years ago. Diamictite is rock made of big pebbles and cobbles glued together with sand and mud.) Prof. K's done a lot of work with the Snowball Earth theory, the idea that the earth was completely or mostly covered by glaciers several times in the neoproterozoic. If it can be proven that this diamictite was left by a retreating glacier, it will bolster the theory, and he offered a steak dinner to anyone who found striations or other obvious signs of glaciation. Unfortunately, the geology is not very clear, for all that it's an absolutely gorgeous outcrop-- probably twenty-five feet of dark gray, polka-dotted stone floating over a picture-perfect Alleghany pasture. Standing under it, I was brought to the fairy caves in "The Perilous Gard," remembering the weight that comes over their inhabitants, the sudden knowledge of the massiveness and age and presence of the rock above and around them. (I can't remember which county the Gard was in, or I'd look up the geology there-- it may be similar; the Alleghanies are contiguous with the Scottish Highlands.)
The next stop was the cap carbonate overlying the (possibly glacial) diamictite. Professor is very enthusiastic about cap carbonates, a worldwide thick layer of marine carbonate rock laid down at the end of the neoproterozoic. This area of Laurentia was undergoing rifting at the time-- you know, those images from dinosaur movies where the earth cracks open and red-hot lava pours out? Yeah, that. So there are flood basalts over the carbonate, and he wanted to show us beautiful flame structures formed when the two semi-liquid rocks mixed. Unfortunately that would have required fording Goose Leg Creek, not a problem in August, but after this winter and spring there was no way, so he took us to his second choice outcrop, which was near the shore of a small pond. Well, usually about ten yards past the pond, but today it was about five feet underwater, so we had to scramble to see it at all. Not very impressive, although we did see trace fossils from cenozoic steel-toothed borer worms, somewhat similar to these images taken on Mars by the Spirit Rover. Apparently people Professor calls Paleomagicians had been doing dating studies suggesting that the carbonate was being deposited contemoraneously with the Vendian ecosystems farther south, which says very intriguing things about the start of macrobiotic life on Earth.
We stopped for lunch at a general store. In my ongoing quest to drink only rare and regional sodapop on trips, I tried a bottle of Cheerwine, which is apparently a Carolina thing. It was very good; like Dr. Pepper, only fruiter and better. If I lived in the area it would probably take over from vanilla coke as my main caffiene source.
After lunch we went to Strasburg, to look at Cambrian carbonates on Old MacDonald's farm. No, really-- that's where it was, a long roadcut with horse pasture above. Carbonates are not real pretty too look at compared with other stuff-- as the Rochester professor who tagged along said, carbonate geology is all about admiring the shades of gray. These were peritidal sedimets, which means beach sand and just offshore, mostly, so there were some okay ripplemarks and cross-stratification. The really exciting stuff here, though (other than the abundant snails and the friendly horses) were the fossils. Giant stromatolites and thrombolites, which are the earliest fossils visible to the naked eye, made by huge colonies of algae, which ruled the earth back before anything evolved which could eat them. Stromatolites are made by layers of algal mats, which get crinkled into these intricate, finely striped wavy patterns; sometimes polished slabs are sold as gem-quality, and they are, really pretty. Thrombolites are just like stromatolites except not layered and not pretty.
The next stop was the one I have to do a presentation on for 1/4 of my grade, Ordovician carbonates of the Beekmantown group, so it wasn't as much fun. It was a roadside outcrop probably about half a mile long, layers and layers of different kinds of sand-y and chert-y carbonates laid down as sea levels rose and fell. The only semi-exciting bit was when we apparently discovered what seemed to be a giant ancient sinkhole or cave system which had been refilled, which would mean that the rock was well above sea level at a time when it probably shouldn't have been. That's something I've loved about all the geology field trips I've been on; even the outcrops that they go to every year, there's always new things being discovered.
That was the last stop of the day. We were camping in Shawnee State Park in Pennsylvania so the caravan started the long drive north. I slept for much of it. We stopped at the Super Wal-Mart in Hagerstown, and Professor Kaufman, who is a far, far braver man than I, took ten college kids grocery shopping for dinner and breakfast on his credit card. Suprisingly, he was the one who kept trying to get us to buy more stuff. We checked out with a self-checkout line, and it only cost about $90. Fun.
The next exciting thing to happen was after we got into Pennsylvania, and got on the Turnpike. When we weren't supposed to. And had to go about seventy miles in the wrong direction before we found an exit. And we were tired and hungry and bored and crabby and it was getting dark. But eventually we made it to the right town, and then Professor Kaufman didn't know where the campground was, so we went around in circles about six times before he found the right park entrance. And then we were so late the ranger station was closed and he didn't know where the group camping area was, and these three huge vans slowly drove past *every campsite in the park* until he finally decided that it was actually one of the first sites we passed. So two-and-a-half-hours behind schedule we finally made camp.
Coming sometime when I'm less exhausted, Part 2: Rumbles of Discontent, Part 3: The Marks of Progress (and Retrogress), and Part 4: Let's Go Play in the Highway.
Saturday morning and afternoon: In which we drop some acid, and then have a very bad trip.
Because dropping acid is, of course, a vital activity for carbonate geologists such as Prof. Kaufman. He even requested that we bring our own; although none of us it, it not being particularly easy to acquire without connections, so we just borrowed his. (Yes, the bad geology puns continued all weekend. Aren't they gneiss?) I got everything else packed and ready: one pillowcase of tent and bedroll, one field pack of geology stuff, one backpack of miscellaneous other. I think I used everything in the field bag and nothing (other than the food) in the backpack.
I was the first one at the meeting place at 6:15 Saturday morning, even beating the professor, because he had locked his keycard and all the van keys in his office. So, yeah, we got off to a later start than planned. But all the junk and people fit in the vans-- the four girls and the female grad student claimed one van as the girls' van, so I spent most of the weekend in a confined space with Dory, Kim, Paula, and Kristina. We did the girl talk thing, too, boys and hair and clothes and gossip and music and sex and drinking and birth control and makeup and all-- and I actually found myself able to contribute most of the time, us all being geology students, after all. Girl talk is fun, once a month or so.
The first stop was at a farm in Fauquier County, Virgina. We traipsed by a stream, over barbed wire and past "Trespassers Will Be Shot" signs to an absolutely spectacular outcrop of neoproterozoic diamictite. (Neoproterozoic is right before the Cambrian, when the first fossils appeared. ~560 million years ago. Diamictite is rock made of big pebbles and cobbles glued together with sand and mud.) Prof. K's done a lot of work with the Snowball Earth theory, the idea that the earth was completely or mostly covered by glaciers several times in the neoproterozoic. If it can be proven that this diamictite was left by a retreating glacier, it will bolster the theory, and he offered a steak dinner to anyone who found striations or other obvious signs of glaciation. Unfortunately, the geology is not very clear, for all that it's an absolutely gorgeous outcrop-- probably twenty-five feet of dark gray, polka-dotted stone floating over a picture-perfect Alleghany pasture. Standing under it, I was brought to the fairy caves in "The Perilous Gard," remembering the weight that comes over their inhabitants, the sudden knowledge of the massiveness and age and presence of the rock above and around them. (I can't remember which county the Gard was in, or I'd look up the geology there-- it may be similar; the Alleghanies are contiguous with the Scottish Highlands.)
The next stop was the cap carbonate overlying the (possibly glacial) diamictite. Professor is very enthusiastic about cap carbonates, a worldwide thick layer of marine carbonate rock laid down at the end of the neoproterozoic. This area of Laurentia was undergoing rifting at the time-- you know, those images from dinosaur movies where the earth cracks open and red-hot lava pours out? Yeah, that. So there are flood basalts over the carbonate, and he wanted to show us beautiful flame structures formed when the two semi-liquid rocks mixed. Unfortunately that would have required fording Goose Leg Creek, not a problem in August, but after this winter and spring there was no way, so he took us to his second choice outcrop, which was near the shore of a small pond. Well, usually about ten yards past the pond, but today it was about five feet underwater, so we had to scramble to see it at all. Not very impressive, although we did see trace fossils from cenozoic steel-toothed borer worms, somewhat similar to these images taken on Mars by the Spirit Rover. Apparently people Professor calls Paleomagicians had been doing dating studies suggesting that the carbonate was being deposited contemoraneously with the Vendian ecosystems farther south, which says very intriguing things about the start of macrobiotic life on Earth.
We stopped for lunch at a general store. In my ongoing quest to drink only rare and regional sodapop on trips, I tried a bottle of Cheerwine, which is apparently a Carolina thing. It was very good; like Dr. Pepper, only fruiter and better. If I lived in the area it would probably take over from vanilla coke as my main caffiene source.
After lunch we went to Strasburg, to look at Cambrian carbonates on Old MacDonald's farm. No, really-- that's where it was, a long roadcut with horse pasture above. Carbonates are not real pretty too look at compared with other stuff-- as the Rochester professor who tagged along said, carbonate geology is all about admiring the shades of gray. These were peritidal sedimets, which means beach sand and just offshore, mostly, so there were some okay ripplemarks and cross-stratification. The really exciting stuff here, though (other than the abundant snails and the friendly horses) were the fossils. Giant stromatolites and thrombolites, which are the earliest fossils visible to the naked eye, made by huge colonies of algae, which ruled the earth back before anything evolved which could eat them. Stromatolites are made by layers of algal mats, which get crinkled into these intricate, finely striped wavy patterns; sometimes polished slabs are sold as gem-quality, and they are, really pretty. Thrombolites are just like stromatolites except not layered and not pretty.
The next stop was the one I have to do a presentation on for 1/4 of my grade, Ordovician carbonates of the Beekmantown group, so it wasn't as much fun. It was a roadside outcrop probably about half a mile long, layers and layers of different kinds of sand-y and chert-y carbonates laid down as sea levels rose and fell. The only semi-exciting bit was when we apparently discovered what seemed to be a giant ancient sinkhole or cave system which had been refilled, which would mean that the rock was well above sea level at a time when it probably shouldn't have been. That's something I've loved about all the geology field trips I've been on; even the outcrops that they go to every year, there's always new things being discovered.
That was the last stop of the day. We were camping in Shawnee State Park in Pennsylvania so the caravan started the long drive north. I slept for much of it. We stopped at the Super Wal-Mart in Hagerstown, and Professor Kaufman, who is a far, far braver man than I, took ten college kids grocery shopping for dinner and breakfast on his credit card. Suprisingly, he was the one who kept trying to get us to buy more stuff. We checked out with a self-checkout line, and it only cost about $90. Fun.
The next exciting thing to happen was after we got into Pennsylvania, and got on the Turnpike. When we weren't supposed to. And had to go about seventy miles in the wrong direction before we found an exit. And we were tired and hungry and bored and crabby and it was getting dark. But eventually we made it to the right town, and then Professor Kaufman didn't know where the campground was, so we went around in circles about six times before he found the right park entrance. And then we were so late the ranger station was closed and he didn't know where the group camping area was, and these three huge vans slowly drove past *every campsite in the park* until he finally decided that it was actually one of the first sites we passed. So two-and-a-half-hours behind schedule we finally made camp.
Coming sometime when I'm less exhausted, Part 2: Rumbles of Discontent, Part 3: The Marks of Progress (and Retrogress), and Part 4: Let's Go Play in the Highway.
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::exceedingly jealous::
See? Life on Mars.
Yay stromatolites! The only ones my profs have talked about have been out on the coast of Australia somewhere. Or, wait, no, that's the only place where they're still alive. Still, yay stromatolites.
Maybe I shoulda been a geology major ...
How long should I be home encompassing June 5? We should go camping somewhere cool while I'm home ...
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The prof said that the Australian critters are actually much closer to thrombolites than stromatolites, if you really look properly.
And Kim's from New York City-- brooklyn, actually. She told us that Manhattan is schist, but Brooklyn is gneiss. q: