Extinct South Africa

 

On Tuesday we decided to explore downtown Cape Town. We started by visiting the oldest establishment, the Dutch fort constructed in the late 1600′s. Among the highlights of the visit were exhibits on the Boer war and the ‘Torture Room’. We then walked around downtown stopping by art shops, street vendors, and the church where Desmond Tutu gave sermons.

After a quick lunch downtown we drove to the V&A Waterfront to depart for our tour of Robben Island (where Nelson Mandela was imprisoned during apartheid) only to find that it was fully booked. Plan B was to take the cable car to the top of Table Mountain, but due to high winds that was also not possible. We settled on the aquarium which turned out to be a very cool place to go. It featured various species from both the Atlantic and Indian Oceans, and was home to one of only two kelp forests in the world which are kept alive in an aquarium. Afterwards we enjoyed a dinner of Kudu and Ostrich at a local grill.

On our last day in South Africa we drove out to Stellenbosch to visit the vineyards. We started at The Bergkelder with a cellar tour and wine tasting, which exposed us to most of the aspects of making wine. It tasted pretty good too! Not much of their wine gets exported to the U.S., but if you have ever seen Fleur de Cap or Two Oceans wine it came from Die Bergkelder cellar.

After our tour we drove to the Spier vineyard for lunch and to see their Cheetahs. Unfortunately we never got to see wild Cheetahs at the game reserve, but this was an acceptable substitute.

Afterwards we returned to the house to collect our baggage and drove to the airport to begin our journey home. It was relatively uneventful (Dan didn’t think he would be let on the plane for a few minutes…) and we made it back to Colby after about 28 hours of travelling. Needless to say, we were a little out of it by the time we made it back.

On our way back to Capetown, we stopped at a small town of Laingsburg. Laingsburg is a field site for oil companies who explore turbidity currents. There are small and large-scale exposures of turbidites. First, we looked at localized small-scale turbidites. The beds, at this outcrop, display a variety of ripple marks and crossbeds. So, we used the ‘stoss’ and ‘lee’ sides of the cross beds to determine the direction of fluid flow. Then we made other stops just outside the town to look at regional scale turbidites. We got to think about the rule of V’s in a real life exposure. It was simply amazing to see large scaled geologic features and think about the time scale.

So after leaving Ganora we made the long drive back to Cape Town for a few more days in South Africa. We woke up the next morning in our beautiful accommodations (we had a whole house!) and drove around Cape Town and the surrounding towns. We went to the beach at Muizenberg, which was beautiful despite the cloudy weather (the forecast had been for bright sun). The clouds cleared out by the end of the day and we explored he V&A Waterfront, a shopping area right on the water. The next day we went to Table Mountain National Park to see the Cape of Good Hope and Cape Point. After being rained on a little (another forecast of bright sun), the skies cleared and it was great to sit on the top of the cliffs with the breeze coming off the ocean. Then, for the last stop of the day we went to a less crowded part of the park where we finally saw some animals, and got to experience an area free of tourists. It was a great first few days in Cape Town!  

It’s time to depart the Karoo and head back to Cape Town, leaving the gorgeous desert sunsets to JP and Hester, our friends and gracious hosts at Ganora.  Saturday morning marks the end of our 4th extended stay near Nieu Bethesda, and it’s always with some regret that we leave them to the peace and tranquility of the region.  Without neighbors or roads close to the farm, and away from the light pollution of the bigger South African cities, a clear evening sky is an image to remember.  Venus, the brightest shining object during sunset, appears at the horizon soon to be followed by the Milky Way which stretches from the horizon across from the house in the image, arcing overhead, and disappearing behind the sandstone outcrop behind the cottage.  The southern cross makes its way into view to the East, and all of the other constellations make their way into view.  Orion’s Belt may look the same, with three stars aligned in a row, but, to us, the stars outlining his sword are upside down.  Our African colleagues jest that this is the correct way to view Orion; we demure.

Objects not normally visible even in a quiet area such as Waterville are now obvious.  There are the satellites that orbit Earth, seeming to float across the sky at a low trajectory, glowing reddish.  Then, there are the meteorites that streak the night, originating from any part of the sky and heading towards the planet, only to be vaporized in their descent.  The more vapor, the better the show.  The pitch black background makes for memorable evenings, allowing us to retain a mental image of how small our planet is, and how much more there is out there that we yet understand.

Our two weeks in the desert examining the rock sequence that records the Permo-Triassic extinction event have given us some perspective not only on the vastness of the universe in which we live, but also of the immensity of Earth history locked away in the geological record, of times past that serve as models for how the planet has responded to times of crisis.  If we can add a little more knowledge to this puzzle, we’ll have been successful.  We won’t remember (or maybe some of us won’t) the long hours, fatiguing conditions, and enormous effort to make small strides towards achieving our goal.  But, we will remember the camaraderie, conversation, and intellectual stimulation that is Ganora.

 

After two weeks of measuring and describing the rocks for each of our sections we have finally finished our fieldwork. Yesterday at New Wapadsberg Pass we finished Tara’s project and collected all the necessary samples. After lunch we drove back to Tweefontein to collect samples for my project and to go through the section to make sure we had written down everything correctly. This morning we returned to Tweefontein to do the same for Dan’s section. Thanks to cores that had already been taken for paleo-magnetism testing there were not many samples left to be taken, so we finished before noon and took a few paleo-current measurements before we returned to Ganora for lunch and some rest before our big drive back to Cape Town on Saturday. A week from today we’ll be back at Colby!

Team Karoo has since been reduced to 5 members after Johann, Rose, John, and Valerie finished their intended projects last week. This left the last standing team members, which include Tara, Kody, Bob, Sandra and obviously me, three projects to complete. At Tweefontein, Kody had to characterize the lower section while I had to characterize the upper section of the stratigraphy. Tara had to characterize a river channel at the Wapasberg Pass.
After a week toiling under the Karoo sun, the team decided to take a break last weekend. We headed north to Mountain Zebra national park, near Cradock, to hangout with Springboks, Wildebeests, Zebras, and Kudus. Some of these fellas had their minutes of fame as they posed and strolled for our cameras. Other animals decided to give us the butt picture shots. One buffalo decided that he had had enough living in the, and so it bust its way into the lodge compound to communicate with humans. The rangers were alarmed; however, I admired the confidence. Big ups to the buffalo!!! I was looking forward to shaking hands with him but he was distracted by the rangers.
After the break, the team came back with loads of energy packed in our bags. On Monday morning, as early as we could, we headed out to the field to continue our work. We have since finished the three projects, and we are left with making sure that everything is what it should be.

Debate continues about exactly when the “Mother of Mass Extinctions,” the Permo-Triassic event, actually occurred on land.  A team of scientists published a paper in the journal Science last November in which they reported on a large suite of radiometric dates from ocean sediments that bracket the extinction event.  But, to date, there are no well constrained dates for when the event occurred on land.  The problem lies in the fact that volcanic ash beds, in which datable minerals occur, are unknown from the sediments deposited on the Late Permian land surface.  With only three days left to this year’s field season, and following several grueling long days of 10-12 hours under the Karoo sun, and a hard night’s sleep (see Dan below with Lulu), we’ve hit pay dirt (no pun intended).

Earlier today we found a new volcanic ash horizon in the vicinity of Graaf Reinet that is close to the reported Permian-Triassic boundary.  The photograph below may not look like much other than some crumbly rock of various olive-gray shades, but a close examination of the image will reveal a white interval that may look like snow.  As an aside, it is hHard to believe, but true, that the mountain passes here often receive centimeters of snowfall during winter, and there are signs warning travelers of road closings….in Africa.  The snow white layer in the picture is volcanic ash, which we collected and will have analyzed by our colleague, Sandra Kamo, University of Toronto, for datable minerals.  This is one of the Rosetta stones for which we’ve been looking.  To date, the Karoo has been unrelenting in giving up its secrets, with teams of scientists searching for such a horizon.  It now may be the time for breaking the locks on the rocks.

Tomorrow we’ll return to the site and complete our measurements and sample collection.  Then, it’s time to begin to check off our list to finalize our field studies before heading to Cape Town this coming weekend for a few days to enjoy South African culture and learn more about its post-Apartheid history.

So after a full week’s work we had a relaxing weekend off. Yesterday we spent the morning catching up on field notes and lounging around. Then, we drove to Mountain Zebra National Park, about an hour’s drive from Ganora. We took an evening drive around the park, taking lots of great pictures of zebra, antelope, and many other animals. We hoped to see some cape water buffalo on our drive, but there were none to be found. However, we were greeted by a ranger at dinner who warned us to be careful on our way back to the rooms. Apparently a buffalo had broken into the camp! Some unhappy rangers were still stationed at the camp gate the next morning. We took another drive in the morning, seeing more zebra and baboons. We drove back to Ganora in the early afternoon, and had a relaxing time reading and enjoying the breezy day. Back in the field tomorrow!

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.