Extinct South Africa

As quick as one can say hippopotamus, the Karoo desert has turned into foreign landscape.  Rather than an intense, hot and radiant sun, with temperatures over 100 F, the skies now are overcast, the breeze cold and strong, and rain has fallen.  It was fleece and sweatshirt weather this evening as we gazed on the southern hemisphere’s display of stars, following the milky way arc across the sky.  There’s nothing like this display in the contiguous United States, and a few hours star gazing makes one realize how insignificant planet Earth is in the scheme of things.

After a week of 6 am mornings, 10-12 hour days in the field, late suppers and early bedtimes, we’re headed for a “administrative” break to compile our field notes, compare ideas, and catch up after a full daily schedule.  Then, we’re off to Mountain Zebra (pronounced zeb-ra) National Park near Craddock for an overnight and some wildlife.  Not that we’ve been remiss in wildlife.  Yesterday, we had zebra cross the road in front of us, wildebeest roaming the grasslands a distance from the cars, and springbok’s leaping on the ridge far from our study site.  But, we’ll be able to get in a late evening (5-8) and early morning (5-8; see a pattern here) drive through the lowlands and high plains of the park.  In addition to the usual suspects–springbok, bontibok, wildebeest, and zebra–there may be a plentiful supply of Cape Buffalo and Kudu.  If we’re especially fortunate, there is always the occasional leopard in the park.  I asked if either Tara, Dan or Kody wanted to “stay up during the night outside the accommodation” and let us know when the leopards arrived, but no one has yet volunteered for this “mission.”

For such a massive chunk of time covered in thirty meters of sedimentary rocks, all of the rocks at the outcrop at Tweefontein are remarkably similar. With the exception of a few meters of sandstone the entire outcrop is composed of coarse and fine siltstones. There is hardly even any variation in the color. At the moment almost every bed is an olive gray with a few that are maroon. Although it may seem tedious to describe thirty meters of the same green rocks it is quite interesting to see dune and ripple structures, as well as several layers that contain animal burrows and fossils that are well over 200 million years old.

Besides measuring and describing rocks we have had the opportunity to help determine the paleo-magnetic orientation of these rocks by measuring the orientation of cores, which will later be taken to a lab to find the orientation of the magnetic grains in the samples. This new information will help correlate time in different rocks based on the movement of the poles during earth’s history.

And although the geology of the Karoo is fascinating, equally exciting has been seeing several different types of antelope, flamingoes, zebras, baboons, and wildebeest. Almost anywhere you go you can see some kind of indigenous African animal from the road or our field site.

Above: The burrow of a Permian animal.

After seeing textbook quality primary structures such as ripple marks and crossbeds at Chapman’s Peak in Capetown, we finally made it, on Friday evening, to the Karoo Basin. Today, the 10th of January is the fourth day in Ganora farm. The farm is located about 10km from Nieu Bethesda in between the spectacular mountains of the Eastern Cape.
Over the past four days, we were introduced to various field methods such as using the handy Jacobs’ staff to measure the thicknesses of stratigraphic sections, using the hand lens, sand-gauge and color chart to characterize different rocks types. On Sunday, Kody and I started characterizing a stratigraphic section in Tweefontein. We encountered the non-textbook type of primary structures, and we have since become experts in spotting the rock color 5Y 4/1.
In short, the past four days has seen us become better geologists. Tomorrow morning, we return to Tweefointein with the hope of learning and finding more structures up the Tweefontein stratigraphic section.
Cheers,

So we have now been in the field for two days. After a long drive on Friday we arrived in the Karoo at Ganora Guest Farm. The farm is going to be our home for the next two weeks and it is a beautiful oasis in the middle of the desert. We found a locality two days ago, Tweefontain, which has been described in previous papers about the area. Today, we spent a long day in the field at this locality. Our goal is to map the stratigraphy of the exposed rock that supposedly extends 100 meters. We began with rock beds near the bottom of a gully carved out by a stream that is currently dry. We worked our way upstream, measuring 1.5 meter sections at a time. Also, found at this locality are fossil plants seen in at least two distinct beds. There is additionally a potential ash layer about 1.5 meters up from where the most fossil plants have been found. We hope that we can correlate the stratigraphy at this site with another site studied previously. We plan to return to the field at the same site tomorrow for another hot day of work!

After a very long and posterior numbing trip from Boston to Amsterdam (7 1/2 hours) and then Amsterdam to Cape Town (11 1/2 hours), we’ve finally arrived in South African summer. Our accommodation is outside of the city, in Constantia, because of a Cricket Test Match with Sri Lanka. It’s all wickets and overs in the media, with the outcome of the tournament providing bragging rights for the next few years. South Africa already lost to Australia in a November Test Match, and Sri Lanka may overtake the Proteas during this engagement. We’re off to stock up on dry food–the selection in Cape Town is much wider than in Graaf Reinet–and begin to adjust to the 7-hour time change.

Today was a day for getting over jet lag, shopping for provisions, wine tasting at Groot Constantia, and a trip to Boulders to see the northern most colony of African (Jackass) Penguins.  Dinner was over a setting sun overlooking False Bay without any notice of a great white shark.

Tomorrow, we’re headed over the Cape Fold Belt into the Karoo Basin, where the rocks of Permian-Triassic boundary are exposed, and will meet up with the remainder of our field party from various parts of the world.

Welcome to our blog! Here we will be writing updates on our trip to South Africa and our study of the geology in the Karoo Basin. On January 3rd Dr. Gastaldo, Tara, and I will depart Boston on our way to Cape Town (where we will meet up with Dan) and continue on to Nieu Bethesda in the Karoo Basin. The internet situation may be spotty but we will do our best to keep you updated with posts and photos of our experience.