Saturday, 11 February 2017

Lake Kariba dinosaur expedition: Part 2

On arrival in Harare we were met by one of our local hosts, Dave Glynn, who whisked us to his house in the suburbs where were to meet the other team members. Dave and his wife Julie run a tourism business in Zimbabwe and organised most of the logistics for our trip, as well as hosting us before and after the fieldwork. They also provided our accommodation at Kariba, placing their houseboat on Kariba, Musankwa, at our disposal. As the day wore on, we were joined by Darlington Munyikwa, the Deputy Director of National Museums and Monuments, and Michael Zondo, from the Bulawayo Museum, both of whom have extensive fieldwork experience within Zimbabwe and had been on many trips to look for dinosaur material all over the country. All of us were to stay with Dave and Julie, to allow an early start on the road to Kariba. That night we were joined by more of the crew, namely the Broderick family, Tim, Patricia and Lucy. Tim was a geologist with the Zimbabwean Geological Survey and had spent many days walking and mapping our study area and his wife Patricia and daughter Lucy were veterans of many fossil hunting trips. Lucy is a professional photographer and was to prove invaluable in documenting our sites and finds. Over dinner we discussed our hopes for the trip and a strategy for making the most of our time around the shores of Lake Kariba.

After a short night and an early start, we packed our vehicles with field kit, 10 days worth of fresh food and other supplies, hitting the road at 4:30 am in order to reach Kariba by early afternoon. It was still dark as we left Harare, but as the sun rose it revealed a beautiful country. Most of the region between Harare and Kariba is farmland and the rains had left the landscape lush and green. After one minor breakdown, which was quickly repaired, we reached Kariba at lunchtime. The Broderick family caught up with us en route, bringing with them another team member, Rowan MacNiven, a fossil-mad restaurateur from San Francisco, whose loud and frequent shouts of “BONE!!!” would become a hallmark of the trip. 

Loading up the speedboats at Kariba and getting ready to cross the lake (photo: Pia Viglietti)

On arrival at Kariba we were met by the final member of our party, Steve Edwards, whose lodge, Musango Safari Camp, was based on the shores of the lake, in prime fossil-hunting territory. This is the point at which our work really began and the whole group was needed to transfer our supplies to the two speedboats that were to take us across the lake to rendezvous with Musankwa. We’d have these speedboats, and two other pontoon boats, with us for the entire trip to allow us to explore the convoluted coastline. With everything safely stowed we boarded and began the 90-minute journey westwards to meet Musankwa, which was lying moored off of the island that was to be the site of our first prospecting trip. The houseboat was essential as camping in the area is potentially hazardous, with lion, elephant, hippo and other game in the areas we wanted to prospect. In addition, it allowed easier transport of stores and was an excellent mobile base for moving from island-to-island and from lake-to-shore.

Some days the commute to work is a lot more pleasant than others (photo: Pia Viglietti)

During our journey across the lake we got our first real flavour of the region. Lake Kariba is one of the largest artificial lakes in the world and is 140 miles (~220 km) long, up to 20 miles (~32 km) wide and has a maximum depth of just under 100 m (although most of it is significantly shallower). It was formed by damming the eastern end of the Kariba Gorge, which forms part of the Zambezi river valley, close to Kariba town, which took place in 1955–59. It forms the international boundary between Zambia and Zimbabwe and was created by the colonial government for the region, prior to the independence of both countries. The lake filled between 1958­–63 and a hydroelectric plant at the dam supplies most of the electricity for both nations, while the lake is used for commercial fishing and tourism. The fringes of the lake are dotted with numerous small islands (which were large hills before the flooding of the valley) and the southern (Zimbabwean) border of the lake is occupied by Matusadonha National Park. The area is densely vegetated, with mopane forest and grassland running down to the shores, and has prolific birdlife and game. During our transfer we were entertained by white-winged terns fishing, African sea eagles flying overhead, and sightings of elephant on the shore and hippo bobbing along the the lake margins. 

Elephant and hippo were frequent visitors to our fieldsites (photo: Pia Viglietti)

The houseboat Musankwa, which was to be our home during our time on Kariba (photo: Jonah Choiniere)

The geology in the area is complex, with much faulting, and the southern shore of the lake is composed mostly of ‘Karoo-aged’ rocks thought to be equivalents to those found in South Africa, which range from Permian to Early Jurassic in age. The area has suffered some drought over the past few years, exposing more shoreline than usual, increasing the amount of land that we were able to prospect. Some of the islands are named, but many are known only by a formal numbering system. Our destination, and base for the next few days, was to be island 126/127. This was chosen as it is the type locality for the earliest known sauropod, Vulcanodon karibaensis, literally ‘the volcano tooth from Kariba’. Vulcanodon, which is known from incomplete remains, is one of the most important animals for understanding the origin of sauropods and all of the available material comes from this island. These bones are now stored in Bulawayo, but one of our aims was to find out more about this site and, hopefully, to find new material … 

The bright orange cliffs that yielded Vulcanodon on islands 126/127, capped by a dark layer of basalt (photo: Pia Viglietti)

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