Geography
Dr Tim Barrows
Senior Lecturer in Earth Systems Science
Key publications | Publications by category | Publications by year
Key publications
Barrows, T.T.M., Hope, G.S., Prentice, M.L., Fifield, L.K., Tims, S.G. (2011). Late Pleistocene glaciation of the Mt Giluwe volcano, Papua New Guinea. Quaternary Science Reviews, 30, 2676-2689.
Williams, M.A.J., Williams, F.M., Duller, G.A.T., Munro, R.N., Tom, O.A.M.E., Barrows, T.T., Macklin, M., Woodward, J., Talbot, M.R., Haberlah, D., et al (2010). Late Quaternary floods and droughts in the Nile valley, Sudan: new evidence from optically stimulated luminescence and AMS radiocarbon dating. Quaternary Science Reviews, 29, 1116 - 1137-1116 - 1137.Abstract:
Our results show that the late Pleistocene Nile in northern Sudan was shifting position and actively aggrading at 145���20�kyr, 83���24�kyr, 32���8�kyr and 20.7���0.2�kyr and indicate, for the first time, a phase of high-energy flow in the White Nile at 27.8���3.2�kyr, with still high but somewhat reduced flow in that river at 13.3�kyr, 10�kyr and 4.8-4.0�kyr. Beach ridges associated with a 386�m strandline of the White Nile have OSL ages of 27.5���2.7�kyr and 14.5���1.6�kyr. The Holocene terraces and former channels of the main Nile have ages of 11�kyr, 6.5-5.0�kyr and 4.8-4.0�kyr, after which there was a general decline in flood discharge. The now arid main Nile valley in northern Sudan was significantly wetter during the early to middle Holocene, with a lake up to 450�km2 in area, fed by an overflow channel from the early Holocene Nile between 9.5�kyr and 7.5�kyr. Previously stable late Pleistocene dunes were reactivated at intervals during the Holocene, with five samples from the White Nile valley indicating brief phases of Holocene dune activity at 9.9���2.0�kyr, 9.0���2.8�kyr, 6.6���0.9�kyr, 4.8���0.9�kyr and 2.9���0.5�kyr, the earliest of which occurred within periods of generally wetter climate and higher Nile flow. The youngest freshwater shells on the Khor Abu Habl alluvial fan west of the White Nile correspond to a time of regionally wetter climate between 1.7 and 1.0�kyr. Our results suggest that millennial scale climatic instability may have been characteristic of Holocene climates in this region. Abstract.
Abstract:
Late Quaternary floods and droughts in the Nile valley, Sudan: new evidence from optically stimulated luminescence and AMS radiocarbon dating
Our results show that the late Pleistocene Nile in northern Sudan was shifting position and actively aggrading at 145���20�kyr, 83���24�kyr, 32���8�kyr and 20.7���0.2�kyr and indicate, for the first time, a phase of high-energy flow in the White Nile at 27.8���3.2�kyr, with still high but somewhat reduced flow in that river at 13.3�kyr, 10�kyr and 4.8-4.0�kyr. Beach ridges associated with a 386�m strandline of the White Nile have OSL ages of 27.5���2.7�kyr and 14.5���1.6�kyr. The Holocene terraces and former channels of the main Nile have ages of 11�kyr, 6.5-5.0�kyr and 4.8-4.0�kyr, after which there was a general decline in flood discharge. The now arid main Nile valley in northern Sudan was significantly wetter during the early to middle Holocene, with a lake up to 450�km2 in area, fed by an overflow channel from the early Holocene Nile between 9.5�kyr and 7.5�kyr. Previously stable late Pleistocene dunes were reactivated at intervals during the Holocene, with five samples from the White Nile valley indicating brief phases of Holocene dune activity at 9.9���2.0�kyr, 9.0���2.8�kyr, 6.6���0.9�kyr, 4.8���0.9�kyr and 2.9���0.5�kyr, the earliest of which occurred within periods of generally wetter climate and higher Nile flow. The youngest freshwater shells on the Khor Abu Habl alluvial fan west of the White Nile correspond to a time of regionally wetter climate between 1.7 and 1.0�kyr. Our results suggest that millennial scale climatic instability may have been characteristic of Holocene climates in this region.Waelbroeck, C., Paul, A., Kucera, M., Rosell-Melé, A., Weinelt, M., Schneider, R., Mix, A.C., Abelmann, A., Armand, L., Bard, E., et al (2009). Constraints on the magnitude and patterns of ocean cooling at the Last Glacial Maximum. Nature Geoscience, 2(2), 127-132.
Williams, M., Cook, E., van der Kaars, S., Barrows, T., Shulmeister, J., Kershaw, P. (2009). Glacial and deglacial climatic patterns in Australia and surrounding regions from 35 000 to 10 000 years ago reconstructed from terrestrial and near-shore proxy data. Quaternary Science Reviews, 28(23-24), 2398-2419.
Barrows, T.T., Lehman, S.J., Fifield, L.K., De Deckker, P. (2007). Absence of cooling in New Zealand and the adjacent ocean during the Younger Dryas chronozone. Science, 318(5847), 86-89.Abstract:
As the climate warmed at the end of the last glacial period, a rapid reversal in temperature, the Younger Dryas (YD) event, briefly returned much of the North Atlantic region to near full-glacial conditions. The event was associated with climate reversals in many other areas of the Northern Hemisphere and also with warming over and near Antarctica. However, the expression of the YD in the mid- to low latitudes of the Southern Hemisphere (and the southwest Pacific region in particular) is much more controversial. Here we show that the Waiho Loop advance of the Franz Josef Glacier in New Zealand was not a YD event, as previously thought, and that the adjacent ocean warmed throughout the YD. Abstract. Author URL
