Research

RESEARCH PROJECTS

Massive flowstone at Bolt's Farm

U-Pb dating early hominin cave sites in South Africa

I have spent the last decade developing the U-Pb chronometer to date the early hominin bearing cave deposits in the 'Cradle of Humankind' outside Johannesburg, South Africa. This work has produced the first set of direct ages for these sites. There is plenty more still to do...

Dating Australopithecus sediba

The site of Malapa, in South Africa, preserves fossils of a new human ancestor, Au. sediba. I was part of the team who dated these fossils to 1.95 million years old. We used U-Pb to date the flowstones and palaeomagnetic analysis of the sediments surrounding the fossils to pin down the age. See Dirks et al., 2010 and Pickering et al., 2011 for more.

Stalagmite SC1 (Green et al., 2015)

Stalagmites as archives of South African palaeoclimate variability

Stalagmites from Sudwala and Cango caves were dated using U-Th and analysed for carbon and oxygen isotopes. We used these proxies to reconstruct the palaeoenvironment at both sites and link this to larger drivers of climate variability. See Green et al., 2015 for more.

Calcrete at Elandsfontein (Braun et al., 2013)

Dating calcrete at Elandsfontein, South Africa

This is experimental work, developing the U-series chronometer to date calcretes and is part of a larger project re-investigating the Elandsfontein site. Careful fieldwork and a lot of trial and error in the lab are beginning to pay off with some exciting results on their way.

Underwater cave in the Dominican Republic (photo credit Laurent Benoit)

Primates of the Caribbean

We dated a piece of carbonate encasing the tibia of fossil primate Antillothrix bernensis recovered from an underwater cave in the Dominican Republic. The age of ~1.2 million years changes our understanding of the palaeobiogeography of this small, island dwelling monkey. See Rosenberger et al., 2015 for more.

1 million year old flowstone at site 13G (Pickering et al, 2013)

The world's oldest sea caves?

The coastal cliffs near the town of Mossel Bay in South Africa preserve an amazing archaeological record. We were surprised to find flowstone and cemented dune remnants as old as 1 million years, which opens up the possibility for more, equally ancient deposits along this coast line. See Pickering et al., 2013 for more.

GRADUATE Students

Jessica Von Der Meden completed her Honours at the University of Cape Town in 2016. Her project is looking at the micromorphology and stable light isotope signatures of the calcretes from the early hominin occupation sites of Elandsfontein in the Western Cape, South Africa. She is currently doing her Masters on more calcretes.

Zoë Decker is a PhD at the University of Cape Town and is working on the lacustrine carbonates of the Kalkkop meterorite impact structure. Her research includes mapping the surface carbonates, as well as looking at some drill core and attempting to date these deposits with U-series.

Tara Edwards is PhD student in the Archaeology Program at La Trobe University and her research is focused at Bolt's Farm in the Cradle of Humankind. She is dating the deposits using palaeomag and investigating the micromorphology of the flowstone layers.

Rebekah Kurpiel is also a PhD student in the Archaeology Program at La Trobe University. Her research focuses on raw material procurement in the Willandra Lakes region in Australia. We used Pb isotopes and trace elements to finger print silcrete outcrops with a view to tracing stone tool sources. Read more about her work here.

Sam Boone is a PhD student at the University of Melbourne working in the Thermochronology and Continental Tectonics group, his thesis is titled 'A low-temperature thermochronology investigation of the Turkana Depression: Implications for the geodynamic evolution of the East African Rift System'. We are experimenting with trying to date East African carbonates with U-series as a side project.

Helen Green graduated from the University of Melbourne in 2013, her thesis titled 'Exploring the palaoeclimate potential of South Eastern Australian speleothems' focused on new stalagmite records from a numbers of caves in Victoria, providing valuable insights into southern hemisphere palaeoclimate dynamics. Helen also worked for me as a Research Assistant while I was on maternity leave, writing up two papers in just 6 months. She is now doing a post doc dating Australian Rock Art with the Kimberly Foundation Australia, read about it here.

Jay Sloman worked on stalagmites from Tasmania for his masters thesis, titled 'Trace elements in speleothems: implications for age models and palaeoclimate'. He is now working as a school teacher - lucky kids!

PUBLICATIONS

Pickering, R. 2015. Middle – Lower Pleistocene U-Pb ages for buried speleothems from Wonderwerk Cave, South Africa. African Archaeological Review, 32, 645-668

Rosenberger, A.L., Pickering, R., Green, H., Cooke, S.B., Tallman, M., Morrow, A. Rimoli, R. 2015. 1.3±0.11 Ma ages for underwater remains constrain antiquity and longevity of Dominican primate Antillothrix bernensis, Journal of Human Evolution, 88, 85-96

Hellstrom, J., Pickering, R., 2015. Recent advances and future prospects of the U-Th and U-Pb dating applicable to archaeology, Journal of Archaeological Science, 56, 32-40

Green, H., Pickering, R, Drysdale, R., Johnson, B., Hellstrom, J. 2015. Evidence for global teleconnections in a late Pleistocene speleothem record of water balance and vegetation change at Sudwala Cave, South Africa, Quaternary Science Reviews, 110, 114-130

Braun, D.R., Levin, N.E., Stynder, D., Herries, A.I.R., Archer, W., Forrest, F., Roberts, D.L., Bishop, L.C., Matthews, T., Lehmann, S.B., Pickering, R., Fitzsimmons, K., 2013. Mid-Pleistocene Hominin occupation at Elandsfonein, Western Cape, South Africa, Quaternary Science Reviews, 82, 145-166.

Green, H., Woodhead, J.D., Hellstrom, J., Pickering, R., Drysdale, R., 2013. Re-analysis of key evidence in the case for a hemispherically synchronous response to the Younger Dryas climatic event. Journal of Quaternary Science, 28, 8-12.

Pickering, R., Jacobs, Z., Herries, A.I.R., Karkanas, P., Bar-Matthews, M., Woodhead, J.D., Kappen, P., Fisher, E., Marean, C.W., 2013. Paleoanthropologically Significant South African Sea Caves dated to 1.0 Million Years using a combination of U-Pb, TT-OSL and palaeomagnetism. Quaternary Science Reviews, 65, 39-52.

Woodhead, J.D., Hellstrom, J., Pickering, R., Drysdale, R., Paul, B, Bajo, P. U and Pb variability in older speleothems and strategies for their chronology. 2012. Quaternary Geochronology, 14, 105-113.

Woodhead, J.D., Pickering, R. Beyond 500 ka: progress and prospects in the U-Pb chronology of speleothems, and their application to studies in palaeoclimate, human evolution, biodiversity and tectonics. Chemical Geology, 322–323, 290–299.

Pickering, R., Dirks, P.H.G.M., Jinnah, Z., de Ruiter, D.J., Churchill, S.E., Herrires, A.I.R., Woodhead, J.D., Hellstrom, J.C., Berger, L.R. 2011. Australopithecus sediba at 1.977 Ma and implications for the origins of Genus Homo. Science 333, 1421-1423.

Pickering, R., Kramers, J.D., Hancox, P.J., deRuiter, D.J., Woodhead, J.D., 2011. Contemporary flowstone development links early hominin bearing cave deposits in South Africa. Earth and Planetary Science Letters, 306, 23-32.

Pickering, R. & Kramers, J.D. 2010. A re-appraisal of the stratigraphy and new U-Pb dates at the Sterkfontein hominin site, South Africa. Journal of Human Evolution, 56, 70-86.

Pickering, R., Kramers, J.D., Partridge, T., Kodolanyi, J., Pettke, T. 2010. U–Pb dating of calcite–aragonite layers in speleothems from hominin sites in South Africa by MC-ICP-MS. Quaternary Geochronology, 5 (5), 544-558.

Dirks, P.H.G.M., Kibii, J.M., Kuhn, B.F., Steininger, C., Churchill, S.E., Kramers, J.D., Pickering, R., Farber, D.L., Meriaux, A-S., Herries, A.I.R., King, G.C.P. & Berger, L.R. 2010. Geological setting and age of Australopithecus sediba from Southern Africa. Science, 328, 205-208.
Fleitmann, D., Cheng, H., Badertscher, S., Edwards, R.L., Mudelsee, M., Göktürk, O.M., Fankhauser, A., Pickering, R., Raible, C.C., Matter, A., Kramers, J. & Tüysüz, O. 2009. Timing and climatic impact of Greenland interstadials recorded in stalagmites from northern Turkey. Geophysical Research Letters, 36(19), L19707.

de Ruiter, D.J., Pickering, R., Steininger, C.M., Kramers, J.D., Hancox, P.J., Churchill, S.E. & Berger, L.R. 2009. New Australopithecus robustus fossils and associated U-Pb dates from Cooper’s Cave (Gauteng, South Africa). Journal of Human Evolution, 56, 5, 497-513.

Backwell, L.R., Pickering, R., Brothwell, D., Berger, L.R., Witcomb, M., Martill, D., Penkman, K. & Wilson, A. 2009. Probable human hair found in a fossil hyaena coprolite from Gladysvale cave, South Africa. Journal of Archaeological Science. 36(6): 1269-1276.

Berger, L.R., Pickering, R., Kuhn, B., Backwell, L.R., Hancox, P.J., Kramers, J.D., & Boshoff, P. 2009. A Mid-Pleistocene in situ fossil brown hyaena (Parahyaena brunnea) latrine from Gladysvale Cave, South Africa. Palaeogeography, Palaeoclimatology, Palaeoecology. 279, 3-4, 131-136.

Sutton, M., Pickering, T.R., Pickering, R., Brain., C.K., Clarke, R.J., Heaton, J.L. & Kuman, K. 2009 Newly Discovered Fossil- and Artifact-Bearing Deposits, Uranium-Series Ages and Plio- Pleistocene Hominids at Swartkrans Cave, South Africa. Journal of Human Evolution, 57, 688-696.

Hajdas, I., Ivy-Ochs, S., Pickering, R., Preusser, F. 2008. Recent developments in Quaternary dating methods. Geographica Helvetia 1, 1-5.

Pickering, R., Hancox, P.J., Lee-Thorp, J.A., Grün R., Mortimer, G.E., McCulloch, M. & Berger, L.R. 2007. Stratigraphy, U-series chronology and palaeoenvironments at Gladysvale Cave: insights into the climatic control of South African hominin bearing caves, South Africa, Journal of Human Evolution, 53, 602-619.

Ustaszewski, M., Herwegh, M., McClymont, A.F., Pfiffner, A.O., Pickering, R. & Preusser, F. 2007. Unravelling the evolution of an Alpine to post-glacially active fault in the Swiss Alps, Journal of Structural Geology, 29, 1943-1959.

Hall, G., Pickering, R., Lacruz, R., Hancox, P.J., Berger, L.R & Schmid, P. 2006. An Acheulean handaxe from Gladysvale Cave Site, Gauteng, South Africa. South African Journal of Science, 102, 103-105.

Pickering, R. 2006. Regional geology, setting and sedimentology of the Middle Stone Age deposits at Sibudu Cave, KwaZulu-Natal, South Africa. Southern African Humanities 18 (1): 123-29.