26 July 2011
One thing I saw yesterday at the Burgess Shale
Posted by Callan Bentley
Comments
One thing I saw yesterday at the Burgess Shale11 Comments
Leave a Reply
One thing I saw yesterday at the Burgess Shale
1 Trackback
AGU Blogosphere | Mountain Beltway | Hiking to the Burgess Shale
on 16 August 2011
Callan Bentley is Associate Professor of Geology at Piedmont Virginia Community College in Charlottesville, Virginia. He is a Fellow of the Geological Society of America. For his work on this blog, the National Association of Geoscience Teachers recognized him with the James Shea Award. He has also won the Outstanding Faculty Award from the State Council on Higher Education in Virginia, and the Biggs Award for Excellence in Geoscience Teaching from the Geoscience Education Division of the Geological Society of America. In previous years, Callan served as a contributing editor at EARTH magazine, President of the Geological Society of Washington and President the Geo2YC division of NAGT.
Have always wanted to see the Burgess Shale. Is it possible to just go there and see it. Have heard it is restricted.
Dan
Dan: check out http://www.burgess-shale.bc.ca/guided-hikes
Dan–
You can only visit with a guided tour. No unsupervised visits are allowed, otherwise people would fill their pockets and clean the place out. See http://www.burgess-shale.bc.ca/guided-hikes/walcott-quarry
Callan–Nice trilobite pic, BTW! Olenoides serratus, if I’m not mistaken. Looks like you lucked out and got a sunny day!
Hi Howard,
Yes: lovely weather on the way in. Though a tad rainy (read: torrential) on the way out. Boots are still drying out.
C
Hey Callan,
Great having you on the hike the other day!
I like this close up; it shows well the characteristic asymmetrical strain many of the specimens from both Walcott’s Quarry and the Mt Stephen beds display. I imagine this is the result of tectonic shear. Any thoughts on this?
Yeah, I think that’s a very appealing aspect of this critter — he’s enjoyed some tectonic torque!
Do you know if anyone has tried to quantify strain using distortion of fossils? I seem to recall having had a conversation with a fellow U-Grad a last year, and he was quite convinced it could be done.
This would be an interesting question at the Kicking Horse Rim, because one of the ideas that was floated about the Burgess Shale’s “survival” a few years ago was that it was protected from the regional deformation (destruction, really, with cross-bedded crenulation cleavage destroying bedding and a very large scale fan shaped structure – the Porcupine Creek fan) of the Chancellor Group (the basinal shales to the west, of similar composition to BS) during the orogeny by a “pressure strain shadow” resulting from the presence of the Cathedral Escarpment. (The reference is the Powell 2003 “greenschist metamorphism” paper I gave you, or at least the plasticine modelling they did to show how the strain shadow might work is reported there.) I wonder if one might be able to confirm this idea by studying the difference in strain using in situ trilobite fossils from several Cambrian sites in the platform (Stephen Fm.), the shadow (BS or ‘thick’ Stephen Fm.), and basin (Chancellor Gr. – if recoverable).
This definitely can and has been done (using fossils as strain markers), though I don’t know about the Canadian Rockies section. I think your ideas about regional application are great — another project once the Mt. Whyte Formation research is concluded!
Nice strain marker. It also looks like a dead animal…
Don’t let looks fool you! 🙂
[…] as I mentioned, there were some lovely […]