15 November 2009

Little Rock City

Posted by Jessica Ball

Long time, no writing! I hate dropping the ball, but schoolwork has to come first. Anyway, I spent part of this weekend exploring the geology of Western New York – specifically, south of Buffalo in Cattaraugus County.

Cattaraugus County moves away from the carbonate sequences that you see around Buffalo and into Late Devonian sandstones and shales. On the map to the left, they’re shown in a sort of pistachio green, while the limestones that I live on are in dark green. (You can find a copy of this map on the UB Library’s map collection website – the resolution isn’t great, but it’s a pretty general map to begin with.)

The weekend was a combination geology and beer-and-wine-tasting trip, but Saturday was a lovely day for hiking, so we went for a visit to Rock City State Forest (roughly near the red arrow on the map). Cattaraugus County has a number of “rock cities” – places where the Salamanca conglomerate caps hills and breaks up into large blocks along joints. According to a K/H Geology Field Guide series book on Upstate New York, “where the rock cites occur, a conglomerate ledge forms a level, ribbon-like outcrop that follows the contour of the hill for a way and then seems to just fade out.”

The rock cities are really fun, and look to be prime bouldering locations; the cracks between the blocks are anywhere from inches to feet wide, so there are lots of alleys and cracks to explore.

The conglomerate is really cool; it has some beautiful cross-bedding, normal and reverse grading sequences, and imbrication in the flat pebbles that make up the largest clasts. The pebbles are mostly white quartz or quartzite, but every so often there are little bits of shale.

I’m too out of practice to be bouldering without a spotter and the right shoes, but the crack climbing was just fine for some of the folks on the trip…
The conglomerate retains water very well – I guess you could consider the blocks “perched aquifers”. There are little dripping springs all over the sides of the blocks, and the water tends to pool at the bases. It makes for muddy hiking, but somebody went to the trouble of putting down wooden walkways in some spots.
Luckily, it was a nice day for hiking; it’s all too easy to get so caught up in the research part of geology that you forget to go out into the field. (The crazy weather up here right now also helped; we should probably be getting snow at this point, but it was warm enough yesterday to go outside in short sleeves! I’m betting this means we’re going to get dumped on this winter.)

I’d recommend a visit to anyone who’s in the WNY area; this is a small but probably underappreciated park that many people would probably overlook in favor of the larger parks (or the ski areas, which I’m sure are lovely when they have some snow…)