First Fold 2009

The traditional "First Fold" picture - see 2008 and 2007). I just can't get enough of this cool folded bed in the lower Prince Albert Formation.
This class was fun - and every one of them was pretty keen in the field! Also did their chores without nagging! Truly a first on both counts. It was a nice one to go out on - my last trip to Laingsburg, at least as a lecturer at UCT.

It was a big year for transitions - as Dr. John Rogers, our sedimentologist with whom I have taught this part of the field course for the last 4 years, will be retiring at the end of this year.
We were lucky to have the two new guys (our replacements) accompanying us for the trip, in a kind of hand-over. It was great to be in the field with them and see all the energy and interest and excitement they will bring to the department. They both saw a lot of research potential in the area too - I hope some of their plans will turn into future Honours projects for these students!

As you can see, they worked well together in the field. All the groups did. I haven't seen their final maps yet but I have a feeling they will be good.
Every year I change it up a little bit - we usually do a "structure training day" and a "sedimentology training day" before they start mapping on their own. This year it went particularly well. I decided to focus directly on field methods instead of rehashing the structure topics we discussed in the classroom. We practiced sketching from afar and ground-truthing the sketch, and talked a lot about scale and planning where to go. Here's an example of a student with his field sketch of a faulted anticline thrusted over a faulted anticline. That peaky Prince Albert Formation sure does take up a lot of the strain in this part of the fold belt.

Here we are on the last day - the last day, for me, of formal teaching at UCT. Pretty sad about that but also looking forward to the next phase of my life.

Visitors are Fun.

For those of you considering a visit to Cape Town, get on with it already! Visitors are Fun! When Visitors arrive I go out to Eat! I see the Sights! and I do ridiculously short field trips to Far-Away Turbidites!

I have had three "reunions" recently as a result of the AAPG meeting - two with blogosphere "colleagues" (Jeannette and Chris), and one with an an actual real-world acquaintance, the notorious Daniel Minisini. These visitors are very intrepid - Chris circumambulated Cape Town to see the Sea Point Contact on his own, and gave an excellent talk in our department. Jeannette found her way (taxi-wise) to campus on her own for Chris's talk, and brought me an amazing and unexpected present without sticking around long enough to be compensated by a trip to above-referenced turbidites. Come back Jeannette! Anyway, watch your mailbox.

Daniel materialized a few days after the meeting was over. Daniel is one of the "crazy Italians" who held court in my grad school lab at UC Santa Cruz - there were always one or more around during the 5.5 years I was there - We were part of some Appeninic exchange program! Daniel probably inspired the most mayhem during his tenure (excepting our RESIDENT Italian, Stefano, the undisputed Maestro of Mayhem).

I won't tell you what happened on Friday because... um... it's blurry.

On Saturday we made lots and lots of food and went swimming with penguins. Can you see how this photo is weirdly funny?
On Sunday, we drove to Laingsburg to see turbidites. Yes, the Laingsburg, which is 3.5 hrs away from Cape Town. We spent an hour or so pondering weird sedimentary structures in the Laingsburg Formation.

We also visited my favorite folds at the "LilyPad Pond". Can you see how this photo is also weirdly funny?
We had the chance to follow up on rumors from past students that there was a cave on the "Whale Back" doubly-plunging anticline that had Bushman paintings. We found them. Small and perfect (but potentially NSFW).
You be the judge.

We stopped at Matjiesfontein for a beer on the way home and arrived in CT at 11pm.
On Monday Daniel and Sila went surfing and hiked all over Cape Point and we cooked another HUGE dinner.
On Tuesday Daniel and Sila are climbing Table Mountain (via Platteklip Gorge) and then ALSO climbing Lion's Head.
On Wednesday I need a nap.

A word about ecotones in the Klein Karoo

OK I have never pretended to be a biologist in spite of a growing fixation on succulents, but there are a few concepts from biology that just seem REALLY IMPORTANT and stuck with me somehow.

The first is the "ecotone" - basically the line marking the edge of the area where a species is successfully living (actual definition is more systemic) - so maybe i don't know the right term but I'm trying to say, the edge of the world for a particular species.

For example, anybody ever driven the Extraterrestrial Highway? Otherwise known as NV state route 375? It was laid out to skirt the Joshua tree ecotone - literally - on one side (south) of the highway there is a semi-geometric grid of Joshua Trees as far as the eye can see. On the other side.... none.

Why do I like this idea so much? It's pleasantly mathematical - as in calculus plus binary - somehow asymptotic to one, then zero. It has a pleasing physics sensation like quantum mechanics - can't see the line when you're looking at it? And in a geological sense - to which it is often correlated, any way - it reminds me of the brittle-ductile transition. A hard and distinct theoretical boundary - but more often than not, shifted or curved by strain rate, temperature, moisture, other mysterious factors.... easy to describe in the abstract, hard to pinpoint in the field. LOVE IT LOVE IT LOVE IT***.

This absolutely beautiful, Georgia-OKeefeish, [absolutely cuter than any foram] pink Aloe plant reminded me of the ECOTONE concept. Succulent people - please name it ??? This beauty and her blushing sisters were found on one hill, in one mapping area, facing one way, on one formation. Literally about 50m³ of real estate, bounded by changes in slope, strike or lithology. Beyond that - another subspecies of different colour, size or shape. To a girl from the California Chaparal this explodes my little mind. Even the plants here are on geologic time.... and the geology? on astronomic time I think. Billions instead of millions. I know I left nothing for scale but that aloe is about a meter across.


Two formations down section - we found this little beast. He is in the lower Prince Albert siltstones, which are pink. OK this section is often madly folded and thickened but the stratigraphic thickness is about 10m. Maybe 15m. Above that: Dark brown siltstones and shales. Below: green glaciomarine diamictites. Literally this guy crosses geologic boundaries and his whole life plan for camoflage is over.
I'm desperately sorry I don't have a photo, but THERE IS A DARK BROWN ONE EXACTLY LIKE HIM IN THE NEXT UNIT UPSECTION. again, a perfect match to the chippy opally silty rocks.


*** You know what i got a lot of crap for recently? "ILOVEITILOVEITSOMUCH".
Turns out this is just more evidence that Americans are flakey. but you know what? IDO FRICKIN LOVE IT SO MUCH. It's that great to be here and see these things. No time for post-colonial understatement.

It's that Field Mapping time of year again

Hey folks I'm back from Laingsburg again with the 2nd year field trip. Every year it seems to get better and better as the sedimentologist and I iron out the plan and I get to know the field. This year's class seemed particularly keen and that makes it even more fun of course. And since they've let me know they found this blog, I'll say they were also clever and good looking, and don't forget to turn in your course evaluations kids. Anyway.

Here's the now traditional "first fold photo" (see 2007 first fold photo). Always a bit of a step up learning about trend and plunge and remembering strike and dip. This year I had an extra prac during 2nd year structure and we used it to do some mock mapping exercises. Seemed like it helped. We were forced by the weather to do things a bit differently this year because it snowed/sleeted on our first day of instruction. What the hey? this is not why I moved to Africa, to field map under ice. At least, not Quaternary ice...

Anyway I'm going to try to arrange some more inclement weather for next year because that was the only day the students complained about the mapping conditions. Awesome.

I digress for a moment to show you a cute tiny angulate tortoise. What could be cuter?

We return to customary annual photos with the "giant pencil cleavage fencepost" installment for 2008 (see 2007 giant pencil cleavage fencepost). This beauty makes use of the Laingsburg Formation turbidite sands.
Sunrise on the last morning in camp:
Time to rise and shine!
more hard core geology posts to come!

Doubly-plunging overturned folds!

We were getting ready to send the students out into the field and I showed them again what the symbols are for putting folds on a map. When I came to the doubly-plunging overturned syncline, I literally said, "I've never seen one and I sincerely doubt you'll need this symbol, but here it is anyway..."

That same afternoon I was out walking around with Cat (the demonstrator) and we came upon this:



I'm calling it the Lilly Pad Pond for now - giving areas and features good names like in Poleta. Just part of my daily quest to be a little bit more like Hilde Schwartz. I'm calling it this because I swear these swirly folds look like ripples in a pond, or like a bunch of lilly pads. It is HECTIC in there! Love it love it.

The clincher of course is that many, if not most of these folds are doubly plunging and overturned!! So I finally saw my first doubly plunging overturned syncline!!! so kickass. Here's Cat in a doubly plunging overturned anticline I'm calling "Cat's Canoe". The Lilly Pad Pond is in the "chestnut" shales of the lower Prince Albert Fm.




The ridge in the background is the Dwyka 4c ridge and the 4f between Lilly Pad Pond and the ridge is quite deformed as well, if not as easy to see due to its weak bedding. I will go back and work on this place for sure.

Samba?

Dancing with the Stars, starring two aloe plants:

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

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 ******