9/30/2009

Stromatolites in the Naukluft Nappe Complex

Finally back in CT for a while. Lots to post but more to catch up on. Here are some cool stromatolites in dolomites of the Naukluft Nappe complex. There's a thin layer of sand over the top of the carbonate bed. I wonder what this represents. Was it a wave that washed sand between the bioherms? Did it kill them? I didn't see the beds above. Isn't it incredible how the sedimentary record is a stack of discrete moments - not a continuous record. Just snapshots.




I love being a geologist because I can hike up a cliff on a dry hot windy day in southern Africa, watch a meerkat shading himself with his tail, scare a herd of Hartman's Mountain Zebra up the slope ahead of me, then sit on this 550-million year old warm shallow sea and imagine a tropical, tectonically active world owned completely by algae and possibly some ediacaran fauna - no shells, no teeth, no fish, no birds. Must have been a quiet and peaceful world.

9/14/2009

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.