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.
Here’s my species list for the past three weeks: African penguin Cape gannet Bunch of gulls (didn’t bother differentiating them) Bunch of terns (didn’t bother differentiating them) Cape cormorant Reed cormorant White-breasted cormorant Cattle egret Little egret Grey heron Saddle-billed stork Marabou stork White stork Woolly-necked stork Hammerkop Greater flamingo African spoonbill African sacred ibis … Read more
Scops owl, Kruger National Park, South Africa Hi everyone! I’m back in the States. There will be more photos of wildlife and geology from South Africa to come in the days and weeks ahead, but this little fellow can be an appetizer for you. It was a great trip, but it also feels good to … Read more
While I was away in South Africa, both Brian Romans of Clastic Detritus and Evelyn Mervine of Georneys posted pictures of folds in quartzite of the Cape Fold Belt in southern South Africa. Well, I’m not going to be left out. Here’s a belated Friday fold for December 23, showing a bunch of sweet folds … Read more
A heads-up: I’m leaving Wednesday afternoon for a 3 week trip to South Africa. My wife Lily and I are off on our half-year-delayed honeymoon (to be distinguished from our Canadian Rockies pre-honeymoon last summer mainly by its exorbitant cost and low levels of geology). We will be spending the day in downtown London, England, … Read more
Folded & boudinaged granite dikes in tonalitic gneiss, Barberton granite-greenstone belt, South Africa. From Passchier, CW, Myers, JS, and Kroner, A., (1990). FIELD GEOLOGY OF HIGH GRADE GNEISS TERRANES. Very crudely annotated: This is a sweet example of how you can get different structures developing in different orientations relative to the principal stress directions. In … Read more
One of my students brought this sample in the other day: She said her father collected it in South Africa. It was labeled “suevite.” I learned the term suevite about a year ago, while touring the USGS Chesapeake Bay Impact Crater coring project samples at the USGS Headquarters in Reston, Virginia. Wright Horton taught me … Read more