Richard M. Bailey
Quaternary climates & environments
Examples of past environmental projects, and some ongoing, are given below. The common theme in these projects is the use of OSL dating to define the relative and absolute timing of events linked to specific geomorphic response to changes in climate. This allows the development of environmental histories and the testing of relevant hypotheses about the operation of the climatic and environmental systems.
Past projects: African lake records—Lake Chilwa (Malawi), Lakes Ngami & Makgadikadi (Botswana)
Samples were taken from ancient beach ridges surrounding the northern shore of Lake Chilwa and dated using OSL methods. The purpose of these projects was to document the hydrological history in these regions by assessing the depositional age of geomorphological features (e.g. beache ridges) which are directly related to the presence of former lake highstands. Results show many distinct periods of deposition, and interestingly not paced by precision-forcing of monsoons. In Chilwa, highstands matched well with dates for N. Hemisphere Heinrich events and modelling using HadCM3 confirmed the existence of relevant physical mechanisms operating through ocean-atmosphere connections. The picture in Ngami & Makgadikadi is more complicated, with tropical signals imported from the Angolan highlands and local lake-climate feedbacks.
David S.G. Thomas, Richard Bailey, Paul A. Shaw, Julie A. Durcan, Joy S. Singarayer (2009) Late Quaternary highstands at Lake Chilwa, Malawi: Frequency, timing and possible forcing mechanisms in the last 44 ka. Quaternary Science Reviews 28, 526–539.
Burrough, S.L. Thomas, D.S.G., Shaw, P.A., Bailey, R.M. Multiphase Quaternary highstands at Lake Ngami, Kalahari, northern Botswana. Palaeogeography, Palaeoclimatology, Palaeoecology 253 (2007) 280–299.
Burrough, S.L, Thomas, D.S.G. Bailey, R.M. Mega-Lake in the Kalahari: A Late Pleistocene record of the Palaeolake Makgadikgadi system. Quaternary Science Reviews 28, 1392-1411.
Past projects: Glaciations in the British Isles
The broad aims of these projects has been to help constrain the timing of major glaciations of the British Isles.
In Ireland, OSL dating was used to help answer a longstanding question over the nature and age of deposits in southern Ireland. This work (headed by Colm O’Cofaigh, Dept. Of Geography, Durham University) concerned the longstanding debate over the ‘older drift’ and ‘younger drift’ deposits, the assignment of these to former glacial periods, and the extent of last-glacial-maximum ice in Ireland. Based on luminescence and radiocarbon results, this work supports a fundamental revision of the traditional interpretation of ice sheet limits in southern Ireland. An extensive ice sheet covered most of southern Ireland during the last glacial maximum (~18,000 years ago) and the moraine belts which have traditionally been interpreted as marking the last glacial limit, such as the South Ireland End Moraine, are reinterpreted here as recessional features formed during ice sheet retreat.
In East Anglia (England), records of glacial deposits were dated using OSL, back to 500,000 years. The lowland region of north Norfolk contains some of the best preserved evidence for glacial deposition during the Middle Pleistocene in northwest Europe. Despite the importance of these deposits, there is limited chronological control and it is debated whether they belong to a single glaciation, equated to the Anglian Glaciation (Marine Isotope Stage 12), or represent deposition over a number of Middle Pleistocene cold stages. Based on optical dating of quartz, we found that the glacial sediments studied were deposited during MIS 12 rather than in different post MIS 12 stages.
S.M. Pawley, R.M. Bailey, J. Rose, B.S.P. Moorlock, R.J.O. Hamblin, S.J. Booth, J.R. Lee (2008) Age limits on Middle Pleistocene glacial sediments from OSL dating, north Norfolk, UK. Quaternary Science Reviews 27, 1363– 1377.
Colm Ó Cofaigh, Matt W. Telfer, Richard M. Bailey, David J.A. Evans. Late Pleistocene chronostratigraphy and ice sheet limits, southern Ireland. In press, Quaternary Science Reviews.
Ongoing projects: details to be added as projects progress
Chronological constraint of the Lake Malawi palaeoenvironmental record
Collaborating with Prof. Tom Johnson, Dr Sallie Burrough, Prof. Dave Thomas
Vegetation history of the Congo basin
Collaborating with Prof. Kathy Willis (Oxford)
Dune chronologies in UAE, matching climate change to sediment records
Collaborating with Prof. Dave Thomas (Oxford), Ms Carly Leighton (DPhil student)
Seal level and tectonic uplift in UAE
Collaborating with Prof. Warren Wood (Michigan State University, USA)
Tectonics in Iran and northern/western Africa
Collaborating with Dr Morteza Fattahi, Dr Richard Walker, Prof. Dave Thomas (Oxford)
Chinese loess chronologies
Collaborating with Prof. Lu Huayu (Nanjing University), Prof. Dave Thomas