You are browsing the archive for south africa Archives - Page 5 of 7 - Mountain Beltway.
15 March 2012
An edgy outcrop
That’s a big pile of alluvial fan deposits (and colluvial debris?) on the eastern edge of the highway leading from Cape Town down to Rooiels. It’s not lithified, but it does seem to be at least partially cemented (perhaps by caliche?), because the outcrop face is essentially vertical, and there seems to be very little sediment that’s falling down onto the road (at least on the day I visited). It’s …
1 March 2012
Sea Point Migmatite
Callan visits the Sea Point migmatite, a contact between intrusive granite and older metasedimentary rocks, along the west coast of South Africa near Cape Town. His guide? None other than AGU Blogosphere blogger Evelyn Mervine of Georneys!
29 February 2012
This is a plant?
Weird plant from South Africa, in the north-central portion of Table Mountain National Park: it’s just two leaves! How bizarre is that? Two enormous leaves emerging from the leaf litter, nothing more. In Namibia, Welwitschia also have just two leaves, but they are much longer (and more prone to getting tattered). I’d love to learn what this thing is – botanical experts, please chime in if you know.
28 February 2012
Kopjes
Spheroidal weathering in Kruger National Park, South Africa. This outcrop is Archean granite of the Kaapvaal Craton. It’s producing a nice little inselberg in the low veld; good klipspringer habitat. “Kopje” is the word I learned to call these things in East Africa, but I guess the proper Afrikaans spelling is “koppie.”
23 February 2012
Contorted fractures in the Contorted Bed
Today, let’s zoom in on a little something I saw at the outcrop of the Contorted Bed in downtown Johannesburg, South Africa: What are these things? I only saw them at this one spot. These look to me like en echelon fractures at a high angle to bedding, that were then deformed due to dextral (top to the right) shearing. But they’re really closely spaced, and they show no apparent …
28 January 2012
Two new bugs
Got access to the wife’s photos from South Africa. Here are two other charismatic insects:
27 January 2012
Friday fold: Twisted turbidites
These are turbidites of the Malmsbury Group in South Africa, on the east shore of False Bay. A couple of nice little folds running sub-vertically through the package… Happy Friday!
26 January 2012
The mixed-up quartzites of Cape Agulhas
Callan and his wife journey to Africa’s southernmost point, and find a geological mystery there.
25 January 2012
Berlin Falls, South Africa
Here’s where to find it, if you want to. Can’t say I recommend it – just an overlook, with no opportunities to hike or swim or explore in any more detail than just passively observing gravity exert its pull on water unencumbered by underlying rock.
24 January 2012
Paleoproterozoic stromatolites from the Malmani Dolomite (Transvaal Supergroup)
After our safari, Lily and I were taken up onto the Great Escarpment in northern South Africa. The escarpment is supported by sedimentary strata of the Transvaal Supergroup that overlie the Archean basement rock of the Kaapvaal Craton. The Transvaal strata are Paleoproterozoic in age, somewhere between 2.5 and 2.0 billion years old. They are a mix of siliciclastic sediment and carbonates. Here’s the view from an overlook dubbed “God’s …
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.