Heritage Cases

Situated beneath the Kalahari sands on the farm Stomp Oor 109 near Marydale in the Northern Cape Province of South Africa is a fossil-rich ancient volcanic crater that has provided a truly exceptional window into a the Late Cretaceous terrestrial ecosystem in South Africa. This was a time when the land surface was being denuded resulting in a scarcity of terrestrial deposits of that age throughout southern Africa. A drill core recovered from Stompoor by De Beers Consolidated Mines Ltd., while prospecting for diamond-bearing kimberlites, revealed up to 76m of lacustrine sediments with excellently preserved fossils of new types of frog (Vulcanobatrachus sp.) and fish (Stompooria sp.) both with rare soft tissue preservation and colour pigments (i.e. melanosomes on the scales of Stompooria). Follow-up pitting ( by Roger Smith and Callum Ross ) along the margin of the crater revealed tantalising vertebrate remains from the site, include a possible bird humerus as well as the impressions of several articulated caudal vertebrae of an ornithopod dinosaur both of which offer huge potential for future finds. The rich invertebrate and plant fossil record includes ostracods, bivalves, gastropods, winged insects, fossil wood, seeds and leaf impressions. As the only known Cretaceous lagerstätte from the Mesozoic of Africa, and one of few Southern Hemisphere localities to exhibit exquisite preservation of soft tissues, the Stompoor cater lake represents a unique opportunity to conduct a full multidisciplinary study of a Late Cretaceous continental ecosystem. Motivation for conducting further research. There is little doubt that based on what has been recovered to date ( Smith 1986a, 1996b, 1988 , 1995, 2005; Anderson 1998, Trueb et al. 2005) the Late Cretaceous Stompoor crater lake deposits contain abundant and diverse floral and faunal remains with soft tissue preservation which is strikingly similar, although considerably older, than the well-known Eocene-aged Messel crater in Germany. The reason that the research potential of this unique fossil lagerstätte has not been fully realised is that it lies beneath up to 42 metres of coarse sand, gravels and clays of the Cenozoic Kalahari Sand Formation. We are here proposing a multinational interdisciplinary project of at least 3 year duration that aims to open-up this deposit, and keep it open for long enough to thoroughly exploit its research potential. Our main goal is to collect geological, palaeontological and geochemical evidence for reconstructing the geomorphic, faunal and floral composition of this unique inland lake ecosystem in southern Africa during the Late Cretaceous, a time when epirogenic uplift caused subcontinent to be constantly denuded with very few places for sediment accumulation and fossil preservation. The areal extent of the crater was delimited by shallow percussion drilling performed by De Beers geologists back in 1980’s , and the depth to the top of the lake deposits was been proven in 3 prospecting pits near the edge of the crater. A single wide diameter core recovered from the centre of the crater contains fossil- bearing crater-lake sediments from 42-112m below surface. We are convinced that large-scale removal of the overburden is essential for the envisaged long-term excavation project. This removal can only be achieved with a singular, yet cost-intensive use of heavy machinery (i.e. bulldozers/earth movers, wheel-loaders and excavators). Facing the expected large initial development costs to access the fossil site, we envisage a large international team involving scientists from South Africa, Germany, USA, and Switzerland. Combined grant proposals will assure a high chance of successful funding. A large team also ensures consistent work at the site even in cases where individual researchers are not available during a particular field season. The special skills of team members include quarrying, fossil- stabilisation and preparation ( Zaituna Erasmus, Nolusindiso Mtalana ( Iziko) and Akiko Shinya (Chicago)), sedimentology and vertebrate taphonomy (Roger Smith (Wits/Iziko) ), fishes ( Mike Anderson (JLB) ) , frogs (Thalassa Matthews (Iziko)), archosaurs (Pete Makovicky (US) and Oliver Wings Germany)), palynomorphs (Frank Neumann/ESI) and macro floral remains including woods (Marion Bamford/ESI). Additionally, experts of other invertebrate (insects, ostracodes, bivalves and gastropods) and vertebrate groups such as turtles and squamates, will be included as the need arises. Applications have been submitted to funding bodies in Europe (Oliver Wings) and US (Pete Makovicky) to cover the major cost of removing the overburden, stabilizing the quarry walls and making good after the fossil excavations are finished. References ANDERSON, M.E. (1998). A Late Cretaceous (Maastrichtian) galaxiid fish from South Africa. J.L.B. Smith Inst. Ichthyol., Spec. Publ. (60): 1-12. SMITH, R.M.H., (1988). Palaeoenvironmental reconstruction of a Cretaceous crater lake in Bushmanland, South Africa. In: Heine, K (ed) Palaeoecology of Africa and the surrounding islands. A.A. Balkema, Rotterdam. p.27-42. SMITH, R.M.H., (1986). Sedimentation and palaeoenvironments of Late Cretaceous crater-lake deposits in Bushmanland, South Africa. Sedimentology, 33, p.369-386. SMITH, R.M.H., (2005) A feast of fossils. Africa Geographic, 13 (7), p. 22-23. SMITH, R.M.H., (1995) Life in a prehistoric crater-lake. Phoenix, 8, p.4-6. SMITH, R.M.H.,(1986) Crater Lakes in the age of the dinosaurs.Sagittarius,1(1), p.10-15. TRUEB, L., ROSS, C. and SMITH, R.M.H., (2005) A new pipoid anuran from the Late Cretaceous of South Africa. Journal of Vertebrate Palaeontology 25(3) 533-547 Methodology and Research Plan Removal of overburden: This will be done by professional contractors using earth movers and/ or rubber wheeled bulldozers following the 20-30 degree dip of the top of the crater facies from the margin towards the centre of the crater in a 15-20m wide trench as deeply as is feasible. As soon as the laminated mudrocks are encountered the bulldozers will give way to the excavating team(s) Fossil excavations will involve gridding and detailed mapping of the fossil bearing slabs before removal. Two excavating teams (one at the deepest point and one half way to the margin ) will work for 10 days to penetrate the crater facies in 5x5m pits to a depth of approximately 5m- or deeper if the walls are strong and safe. The application of consolidants is not advised due to the high moisture content of the mudrock. Rigid packaging for transport to Iziko SA Museum is essential. The specimens will be damp when collected and thus need climate controlled storage and slow drying, prior to preparation/scanning/study. Care will be taken to not split the slabs on site- rather wait to do this under laboratory conditions to prevent all the skeletons from being broken in half along bedding plane. Provided the project is fully funded and that the quarry walls do not collapse between seasons it is envisioned that we will be able to do 2-3 annual field seasons should the potential warrant the further effort. Providing that the SAHRA permit is granted we envisage the first season beginning in October/November 2021. It is intended that all specimens collected will be transported to Iziko SA Museum’s Karoo Palaeontology laboratory for further stabilisation, preliminary preparation and closer inspection. After preliminary preparation and/or CT scanning all worthwhile specimens will be accessioned into the Iziko Karoo Palaeontology collections and entered onto their Specify database. Batches of study specimens may then be loaned to various institutions for further work. Drying, consolidating (limited to rock surfaces only), and controlled parting of the dried mudrock slabs will be conducted at Iziko SA Museum Karoo Palaeontology laboratory. No exposed fossils will be coated with any consolidants as this interferes with detailed studies of soft tissue preservation. CT scanning has proven to be an effective method of studying the previously collected frog specimens which will allow us to see the 3-D arrangement of the skeletons without the need for disrupting them by splitting or preparing with mechanical tools. Larger dinosaur vertebrae have been successfully prepared out mechanically, others that have been partially weathered have been carefully removed, leaving an external mould that is then cast with silicone rubber. Anticipated academic outputs Depending on what we find, the results of the first season’s excavations will be written up in a short report for a high profile journal such as Plos-One or Nature Communications with the view to securing further funding to maintain the integrity of the quarry and remove more overburden. Envisioned research topics leading to publications: Taphonomy of Late Cretaceous frogs in a volcanic crater-lake mass death scenario. Melanosomes of Late Cretaceous galaxiid fishes Significance of dinosaur remains linked with Cretaceous –aged volcanism in South Africa. Palaeobotany of a Late Cretaceous crater lake deposits in Bushmanland South Africa Transformation This project will provide a tremendous opportunity for the technical support staff of Iziko SA Museum and the Evolutionary Studies Institute, who are predominantly non-white, to take the lead in the excavation and curation aspects of this project which are the main activities planned for the coming field season, and which will determine whether the project will be able to run for2 or 3 years. Zaituna Skosan (Iziko Karoo Palaeo collection manager) will head up the technical team and ensure that the excavated material is professionally handled, transported and stored. She will also be responsible to reporting back to SAHRA. Nolusindiso Mtalana (Iziko Head of Karoo Preparation Lab) will oversee the mechanical preparation of the dinosaur bones that are robust enough to allow this procedure. Although this project is in its infancy- we fully expect to provide valuable field training to honours and masters students who volunteer to help with the excavations as well as numerous research topics for these and future graduants. Data Management The primary data relating to 3-D co-ordinates, stratigraphy, sedimentology, lithology and taphonomy that will be recovered during the excavation phase will be collated by the PI’s and collection manager and backed up to Iziko server as well as their home institutes. Following taxonomic review of the material and detailed analysis the new taxonomic data will be entered onto the Specify database and the specimens then officially accessioned into the Iziko Collections. These data are then available to any bona-fide researcher on application to the director of collections at Iziko SA Museum. Science Engagement Despite the tremendous wealth of fossils in the crater lake deposits at Stompoor - they are far too remotely situated, and far too deeply buried to be considered for an open dig site visitor centre or similar site museum enterprise. Thus the best opportunity for science engagement is through the internet- daily blogs during excavation season, webcams at site and in the lab, bringing the field to the people rather than the other way round. The small display on the Stompoor crate lake in the African Dinosaurs gallery at Iziko SA Museum can be used as a hub for releasing new developments in this project. The live Karoo Fossil Demo-lab is right next to this display and as such is well- positioned for the preparator’s to engage with groups of learners as the new fossils come out for preparation and/or publication.