20 February 2011
A tour of deskcrops
Posted by Jessica Ball
The weather in Buffalo this weekend has gone from warm and rainy to windy and snowy to tolerably cold and sunny, with potential for more ickiness tomorrow, but for someone who likes to be warm and comfy on the weekends this doesn’t make for fantastic hiking conditions. So I decided to photograph some extremely local outcrops (otherwise known as “the ones inside the apartment, where there is heat”). None of these are actually on my desk, but I think they count as “deskcrops” (outcrops that are no longer in-situ and have often experienced extreme geographical displacement).
Starting with the mantel, we encounter a variety of volcanic clasts from extremely varied origins. (I suppose this is a volcaniclastic region, although nothing’s holding them on the mantel except gravity. It’s a good thing the cat won’t fit up there!) Here is a spindle bomb from Llaima Volcano in Chile (center), a piece of pahoehoe basalt from Hawaii (right), and two bits of andesite from Arenal Volcano in Costa Rica.
On the mantel’s other side, some more Arenal andesite (left and right), a bit of dacite from Poas Volcano (Costa Rica), and a piece of the 1800 Kaupulehu lava flow on Hualalai Volcano, Hawaii (it contains some wehrlite xenoliths, but they’re hard to see here).
And a bit more to the right, a lovely breadcrust bomb from a pyroclastic deposit on the Island of Procida, Italy, next to another lava bomb from the same formation (right).
Moving a few meters to the west, we come to two forms of quartz: Blue quartz from Virginia’s Blue Ridge Mountains, and Herkimer “diamonds” from Herkimer, NY.
Half a meter up in this outcrop, we find some Hawaiian basalt with an unusual xenolith…and an age of 1,731.5 days (~4.7 years).
And some hematite “blueberries” from outside of Big Bend National Park, TX.
Below that is a varied assortment of clasts and fossils (maybe a diamicton?). Click to zoom in – there are lots of things to see here. (That chunk of basalt in the bottom left is from somewhere in New Zealand, but the person who gave it to me neglected to mention where; I ran out of steam and space for labeling, so there are a few mystery rocks as well.)
Finally, we move on to the far western end of the study area, where a sample of Niagara Falls-area Whirlpool Sandstone (with cross-beds) is holding down one side of my draft-preventing device (a curtain)…
…and a bit of Blue Ridge (VA) granitoid gneiss has the other side covered.
There’s a nifty fold in this one, but it’s easier to see from the side. Sabrina (the official scale cat for Magma Cum Laude) wanted to make sure you had a sense of scale in this one.
And that’s the tour! I left out a few bits (mostly things I’ve featured before), as well as the random decorative rocks in the bathroom, because I can’t remember where they all came from. They’re mostly glacial dump from the shores of Lake Erie and Lake Ontario. And I also left out the rocks in the fishtank, because the fish has a taboo against being photographed – being a betta, he’s not as friendly as the cat.
Love the hawaii basalt with xenolith. I think I might have a snapshot from the instant of its formation!
My favorite too!
this is great
i always mean to photo-catalogue my own rocks before i start forgetting where they came from; i might copy your model