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19 June 2012
101 American Geo-Sites You’ve Gotta See, by Albert B. Dickas
I just finished reading 101 American Geo-Sites You’ve Gotta See, one of the latest publications by geology-friendly (and Missoula-based) Mountain Press. I’m grateful to the the publishers for sending me a review copy. It’s a nicely written and produced book highlighting sites across the United States of America of geological interest. The book is organized in a series of two-page spreads. On the left is a one-page write-up of the …
20 January 2012
Friday fold: one from Romney (West Virginia)
Last weekend, my wife and I joined friends for a weekend of cross-country skiing in the wonderful Canaan Valley of West Virginia. On the way back, between the towns of Burlington and Romney, West Virginia, I saw this folded shale on the north side of Route 50: You can click on that panorama to make it a thousand pixels tall, if you want to explore it a bit. There are …
19 January 2012
Mudcracks
Here’s two nice examples of mudcracks I saw used as paving stones in South Africa:
17 January 2012
The ventifacts of Rooiels
Site of the mystery photo I posted over the weekend, the beach at Rooiels (“red grass” in Afrikaans), South Africa, is a lovely place… Located on the western side of False Bay a tad north of Cape Hangklip, Rooiels is somewhat famous in my mind because the Guru of Gigapan, Illah Nourbakhsh, spoke glowingly of it at the November 2010 Gigapixel Imaging for Science conference in Pittsburgh. When I finally …
6 January 2012
Friday fold: the Contorted Bed
Callan reviews the geology of the superlatively auriferous Witwatersrand Supergroup of South Africa, and then zooms in on a distinctive marker bed near the base of the sequence. The deformation in this particular banded iron formation (BIF) is an aesthetic wonder, as this suite of images reveal. The layer outcrops in the heart of urban Johannesburg.
27 October 2011
Pavement outcrops of strained Seine conglomerate
Picking up from the astonishing first couple of outcrops we saw of strained Seine Group metaconglomerate from the boundary between the Wabigoon and Quetico sub-provinces of the Superior Craton, our group moved on down the road. It was lovely clear fall weather near Fort Frances, and shockingly warm. Our third stop of the morning was a lunch stop atop a great “pavement” outcrop of the same strained metaconglomerate, showing different …
1 July 2011
Friday fold: west Bighorn monocline
While out in the field with Butch Dooley last week, making major discoveries like I do, I was very impressed with the landscape-scale west Bighorn monocline, which takes formerly horizontal Madison limestone and skews it to a westward dip where the mountains end and the intermontane basin begins. It’s totally sweet. Check it out in photo form and gigapan, too.
7 June 2011
The grave of John Wesley Powell
Callan visits the grave of John Wesley Powell, second director of the USGS and explorer of the Grand Canyon, on an afternoon in Arlington National Cemetery.
10 May 2011
Four new gigapans from the Billy Goat Trail
Yesterday afternoon, I spent some time in the field with a colleague, a student, and a gigapan. I took four gigapan images, which are of varying quality due to the partly cloudy day, but still you ought to find them interesting to explore. You can see any of them full-screen by clicking on the word “GigaPan” in the lower right corner: Antiform in Mather Gorge Formation, C&O Canal: Folds and …
30 March 2011
Rusty rinds on peely rocks
Another group of interesting cobbles from the same sand and gravel pit that I described earlier in the week: Here’s the same sample, gone all animated, for your perspectivizing pleasure: What we’re seeing here is some fine-grained gray colored rock (siltstone, I guess?) that’s developed a pronounced weathering rind marked by a large amount of rust. This rusty rind is tougher than the original, unaltered rock, and it peels off, …