Samba?

Dancing with the Stars, starring two aloe plants:

Sorry but this reminds me of Spanish dancing for some reason.

Friends in the garden

I spent the weekend decompressing and marking papers. Gawd do I hate marking papers. Luckily I have some friends in the garden.

My broccoli is starting to make something which looks like tiny broccolis! There was a beautiful green mantis on this big plant the other day.
We also have this kitty: He is old and loud. He likes milk and hates peanut butter. What should I call him? "Old loud kitty" is not a great name for him. He waits for me most mornings to scratch his ears even though I have only given him milk twice - he remembers.

Big Pencils

These massive tillites take the fold-axis effect : Pencil Cleavage to new heights.

Sorry but this is like Art.

Some microfaults in Rooinek Pass.

There were also some people out there

Apparently there is only one person who reads my blog, and that person is a sarcastic SOB. That would be Crazy Jonny who sends me rude emails about formerly extinct fish. Anyway just to reassure you that the next 10 posts are not all going to be about rocks, I will provide you with some images of students using compasses (with varying degrees of success).

Anyway I like this class, they were fun and big and boisterous and generally ok in the kitchen and each and every one of them has a whopping personality. You can't tell from these photos though, because these depict the "learners" performing

Here we have Oarabile measuring the trend of a nice tight plunging anticline with some consultation from Tshidi. Some signs suggest that OB knew how to use his compass at this point, although for a practical only 2 weeks earlier they had to repeat a single strike/dip measurement 10 times and calculate the standard deviation. Several students were showing standard deviations of up to 50°. Not sure physically how to do that unless you have an iron peg in your compass arm or something.


Next we have demonstrator Nic Laidler indicating the attitude of the axial planar cleavage of the fold he is standing on with Tanya and Caitlin. You can see from the look on Tanya's face (yellow shirt) that she is not too impressed with my "roadside geology" methods of waving your compass toward the trace of the axis. Tanya likes specifics! Caitlin is more trusting, perhaps.

This is the second group to map the Floriskraal Anticline. I accompanied this group on their first day to make sure they escaped the downfall of the first group, who maybe just a little bit didn't find the anticline in the Floriskraal anticline. Future students: if A overlies B, and you see the sequence A-B-A on your map, let anticline be your first working guess... until I tell you about faults that is (evil laughter)

Now I know what Barb secretly wants. She wants me to tell you the name, home language, life history and religious background of each of these students. But who would I be if I kept such data? I would be John Rogers! So Mom, if you want such data, you should write to him directly. I will tell you we had a 7th Day who had to be given an extension because he couldn't write up on Saturday. There are many different religions among the student body, a small subsampling of the more observant ones in one class will mean that there are students who don't work Friday, students who don't work Saturday, and students who don't work Sunday. Now imagine trying to run a field trip - which at that cost and time investment - can not be run multiple times. It looks like the department is going to move toward a "work or receive no credit" type policy with wiggle room for accommodating anyone's needs as possible (but no guaruntees of allowances). Awkward feelings about this.

Springboks

This post should be about the rugby game last week but it's really about baby animals. Funny how I always think my photos are so much better than they really are. Click on the photos to make them bigger. There were a lot of springboks in the map areas this year. I also saw 5 bat eared foxes - in the same valley as Nicci and I spotted the pair a year ago - could it be the same foxes with 3 new kits? They definitely live there as the students who mapped that area saw them several times in the same place.





So you're wondering, "what is that unusual massive but friable pressure solution-cleaved greenish diamictite the springboks are grazing on?" Why, that's the Dwyka 3c ridge - one of the last coarse sequences of the Dwyka glaciation at the end of the Carboniferous period. Here's a nice fresh surface in the Witteberg River showing some late fracture cleavages cutting the clasts - don't worry, I had my NEW BRUNTON and I measured it to the nearest minute - and yes, it is post-folding. Wow.


Just for comparison, here's a more weathered outcrop of the fine-grained, laminated Dwyka 4f - including a characteristic big brown dolomite/phosphate nodule.

Nerding out on Some Old Bugs

This incredible trackway - in the Permian Collingham Fm., Ecca Group - Maybe it's a eurypterid trackway? It doesn't look like the other eurypterid trackways on the internet. Hilde? Help? Whatever made this was something huge! Here's paleontologist John Almond sitting on the same outcrop for a SABC show about the Dwyka glaciation / Ecca Sea.

A bit of paleo-environmental background and a few questions:
The Dwyka Group (Carboniferous-Permian) contains a minimum of 3 regressive sequences - mostly glaciomarine diamictite, laminated or massive. There is some weird shiznit in there, including Banded Iron Formation boulders (which I have only collected one large hand sample of but must get more!) The warming sequence is the Ecca Group - brackish to marine, transgressive sequence - begins with a silt/shale unit of variable colour and fresh water del¹⁸O (Prince Albert Fm) which is gleefully structurally destroyed in the Laingsburg area but my guess is no more than a few 10s meters thick. More on that later. That is overlain by gypsum-bearing black anoxic shales (only a few meters): the Whitehill Fm. The Collingham Fm. where these trackways are found is more normal looking turbiditic sequence with blackish shales and gray siltstones. Not sure about salinity. Above that we get coarser and more sandy turbidites for hundreds, more like thousands of meters. There's not much published on these formations - and the work is quite old. From a shallow survey of the eurypterid literature, it looks like by the Permian most of the big guys are showing up in brackish-fresh anoxic lagoons and sometimes hypersaline lagoons.

This leads to my big question about the whole Ecca Group, and indeed the Dwyka Group as well - aren't these to some degree marginal environments? Where on earth today can one find a place like this? The Black Sea perhaps if it were near to the South Pole, as the inland Ecca Sea was during the Carboniferous-Permian? What about the Dwyka - how are the massive diamictites deposited, and are they in fact true tillites? Both the massive (aka "coarse") and laminated subunits have dropstones and are mostly rock flour except for the 1c-2c "Boulder Bed" (See John Rogers' photo here). I guess I should read the papers before I get on my soap box but doesn't this sound like sub-ice sheet deposition, with maybe varve cycles developing during times of thinning and/or increased seasonal sensitivity in the basin?




Finally, the Burgess Shale mystery animal Hallucigenia has been positively identified and is extant in the Succulent Karoo. This is going to be bigger than the coelocanth.
The Cambrian fossil

My photo



**** sorry for the nerdy jokes, I am tired from the trip ****
****** I hope Al Curren is proud that I recognized Hallucigenia on sight ******

I think someone is calling me a nerd.

Avid readers may recall that I gave a couple of mentions to Alaska blogs I regularly read. Turns out Ishmael uses the "links to this blog" feature.

Those kind words from Christie, a geologist who spent summer here last year and is now teaching in South Africa. I think. Most of her blog is in Greek. Or Latin. Witness:

{here he quotes my Worcester rocks post}

But it's pretty witty and breezy writing, and I think I recognize a couple of those words from college, though.

I'm especially humbled by her listing the KoKon on her blog under "things i read over lunch."

Hey Ishmael! you should see what I've got on the Rock. Turns out South Africa 600 million years ago wasn't so different than Kodiak 60 million years ago. Who'dathunkit. working conditions can be quite different however:
Me, cranky, Isthmus Bay (Chiniak), Alaska June, 2002: Photo by my adviser J. Casey

Me, happy, Worcester, Western Cape, South Africa, September 2007: (self portrait taken with aid of boulder of nasty coarse vein quartz! This puppy has got to be chalk full of fluid inclusions! But no carbonate in sight (no pun intended)).

Taco Mystery: Solved!!!

What a day what a day! One Leonard Creo (no link provided) commented on my Taco post the following clue:
"I've been chasing this one for years....suggest you google "nixtamalization."
...and investigate history of Pelegra in any of the high mealie cosumption areas in SA ."

Do it! Do it! Google it!
Here I'll help:
link to wiki article on nixtamalization

In the Americas, the corn is cooked and seeped with lime water (1% CaO) which separates the outer hull from the grain. This causes a variety of chemical changes including increasing nutritional value significantly! I had underestimated the importance of the lime.

So the mystery is solved, and my path to the taco lifestyle is lengthened considerably... can I buy dry samp and boil it with CaO and dry it and grind it?

Phase II begins after the field trip.

Worcester for the Weekend ! Rocks !

Yee Haw! Finally a weekend outside. Soooo beautiful near Worcester, just on the eastern edge of the Syntaxis of the Cape Fold and Thrust Belt. Thirteen students, myself, and two post-grads, sunshine, birds, bugs, fynbos in bloom, a cozy wine farm, and good driving directions. Field trip bliss.

(Manditory photo of living thing)Check out this beautiful Aloe! My friend Nicci painted this one. I think it's the same one as Laingsburg. Thanks to Nicci I noticed subtle changes both in the spatial distribution, frequency, and morphology/colour of aloe as I walked up and down the hills. The fynbos is so highly derived some of those plants have a 20m ecotome. Not even exaggerating!

Ah, but what is that lovely outcrop in the background, you ask? Well dear friends, it is the leading edge of the Peninsula Formation (Table Mt Group) thrust over the Malmesbury Group. Now, if you were in a hurry you might just think that the Peninsula always unconformably overlies the Malmesbury so what's the deal with calling it the leading edge? But that would mean you had missed this:
The basal cataclasite. Gritty as can be and with a suspiciously fractal-looking grain size distribution. OK so I didn't measure any grains but it sure as hell isn't sandstone. Nor is it limestone in spite of some opinions I heard in the field. Not everybody shares my enthusiasm for the oral textural analysis (sorry Bill) but it sure can tell you the difference between calcite (mohs hardness 3) and quartz (mohs hardness 7). Someday I'll post a tutorial. That will have to be for Heather's weekly gross-out.

Before I get too far along, must show you a map:
Each map area is about 3.5 km2, each student had 2 days to map one area. I mapped both (but didn't walk the whole place) and in the process reassured myself that I am up to the job. Thank goodness for Hilde and Poleta. In fact, thank goodness for "the Scissors" because it helped me out I think. I won't post my map here because I need secrets for next year. In fact I am having doubts about putting my interpreted photographs. Maybe if I remove all potential search terms no students will find it?

We'll start with some basics. The Malmesbury Group is a big pile o' turbidites, but pretty much the least deformed accretionary wedge I've ever read about. In fact I live on MG (covered by colluvium) but it never outcrops. In the mapping area it is low greenschist facies, phyllite, with a nice sheen. Bedding is cryptic most of the time, unless you find one of these kick ass pebble beds. Here's one for anybody who needs to see what S₀ - S₁ intersection is all about! Stereonet shows bedding/cleavage intersection.
The MG is tightly folded - S1 is the axial planar cleavage (according to urban legend, I have yet to see a fold axis, why does this remind me suddenly of Cummington MA and H. Bob Burger and Lena reaching into the isoclinally folded turbidite outcrop and coming out with a pissing fistful of garter snakes? Because nobody had seen a fold axis there either. But I digress.) So here we have established the angle between bedding and cleavage is about 30 degrees. This held true everywhere I measured it (again, no fold axes!!) So maybe it's just as likely tied to imbrication and underplating. Who's to say. Either way it is early - right?

The same outcrop from another angle. Streched Pebbles! "Cigars" as we call them. Strain ellipse proxies extraordinaire! Funny thing - the e₁ axis lies in the S₀ plane and not in the S₁ plane. What does that mean I wonder?

Complicating the matter - here are some relatively late porphyroblasts - I think they are chloritoid - they are also stretched, but in S₁. I don't know how I forgot to measure the trend and plunge of these but oh well, something for next year I guess.

But what about the faults christie! Well you'll have to wait for the next post. Hooo boy do I have some faults to show you. In the meantime, here's my intentionally obtuse schematic to tide you over.

off to Laingsburg on Saturday morning - expect 8 days radio silence...