9/16/2006

Big Time Laingsberg Structural Geology!!!

Ah Laingsberg. Home of the famous Karoo Lamb - naturally spiced by its free range diet of wild herbaceous plants. I couldn't bring myself to eat a lamb chop (especially after a visit to the abattoir which is the butcher) but I do admit to having a few bites of the mixed-meat Boerewors (pronounced BOORVORS) which is a traditional farmers' sausage, super fatty, and very flavorful.

"Braai"-ing ("BRY") is just not done with briquettes here. Our coals came from an old apricot orchard on another part of the farm which the farmer took out during the winter. We built a large fire outdoors and let it burn down to a bed of coals. Once the coals are spread out, the "vegetables" go in - these are foil wrapped potatoes, jam squash and butternut (emptied of seeds and sprinkled with salt and pepper). Whole onions might be cooked this way too. The meat goes in this giant folding grill thing (2 grills, hinged with a long handle) and balanced it over the coals on a pile of rocks. The Braai is taken quite seriously by all involved. All the students in both classes seemed to know exactly how to cook perfect lamb and how to time everything to come out of the braai at the same time. One night we went to a braai with the Stellenbosch second-years, led by Dr. De Ville Wickens, who knows how to throw a party. Sadly the UCT kids all fell asleep in a corner together, wiped out by their first day of mapping. Sorry Maties.

OK to keep with the theme of this post, living LARGE South African style, let me show you some BIG TIME STRUCTURE.



Some gorgeous folds in Rooinek Pass. Rooinek of course means "Red Neck" which is a mildly durogatory term for Englishmen who came out to the Karoo and burnt to a crisp. In effect this is the opposite of what Americans mean when we say "redneck" as it is a slur on a city slicker for burning easily. This is what my associate John Rogers loves to refer to as an "afternoon shot".



The best anticline (and most interesting structure) in the field area! I've put my caption on the photograph itself so it won't be searchable by prying 2nd years.



To substantiate my claim that the repetitions mentioned above are due to axial plane-parallel thrusting in the hinge, and not by simple parasitic M-folds, here is a sheath fold in the shales in the hinge area. Note steeply plunging axes with opposite trends. Note tiny scale! Strike symbol shows approximate orientation of thrust, dip > 80S. There is lots of "catcher's mit"-like folding in the hinge as well - for those of you familiar with the Poleta Folds and "the Scissors".

1 comment:

spontaneous k said...

Im a second year geology student @ Uct and just today I gt back from Lainsburg fieldtrip,I beat myself up 4 not researching abt da area before the excursion,,epicness I agree da structure is intense,and I saw a pafader just as I was abt 2 take my strike n dip measuements,IM inlove with geology n Im a fan of ur writing,Im sad u wnt be lecturing us,I was really lookin fward 2 it.will u be gtn back soon?
Id like to chat with u abt a few things coz I really think u kwl,pls send me an email on kholofelo21@gmail.com

Hope