Preserving the palaeoenvironmental record in Drylands: Bioturbation and its significance for luminescence-derived chronologies

被引:115
作者
Bateman, M. D.
Boulter, C. H.
Carr, A. S.
Frederick, C. D.
Peter, D.
Wilder, M.
机构
[1] Univ Sheffield, Sheffield Ctr Int Dryland Change, Sheffield S10 2TN, S Yorkshire, England
[2] Univ Texas, Dept Geog & Environm, Austin, TX 78712 USA
[3] Geo Marine Inc, Plano, TX 75074 USA
基金
英国自然环境研究理事会;
关键词
bioturbation; luminescence dating; Florida; Texas; Kalahari;
D O I
10.1016/j.sedgeo.2006.07.003
中图分类号
P5 [地质学];
学科分类号
0709 ; 081803 ;
摘要
Luminescence (OSL) dating has revolutionised the understanding of Late Pleistocene dryland activity. However, one of the key assumptions for this sort of palaeoenvironmental work is that sedimentary sequences have been preserved in tact, enabling their use as proxy indicators of past changes. This relies on stabilisation or burial soon after deposition and a mechanism to prevent any subsequent re-mobilisation. As well as a dating technique OSL, especially at the single grain level, can be used to gain an insight into post-depositional processes that may distort or invalidate the palaeoenvironmental record of geological sediment sequences. This paper explores the possible impact of bioturbation (the movement of sediment by flora and fauna) on luminescence-derived chronologies from Quaternary sedimentary deposits in Texas and Florida (USA) which have both independent radiocarbon chronologies and archaeological evidence. These sites clearly illustrate the ability of bioturbation to rejuvenate ancient weathered sandy bedrock and/or to alter depositional stratigraphies through the processes of exhumation and sub-surface mixing of sediment. The use of multiple OSL replicate measurements is advocated as a strategy for checking for bioturbated sediment. Where significant OSL heterogeneity is found, caution should be taken with the derived OSL ages and further measurements at the single grain level are recommended. Observations from the linear dunes of the Kalahari show them to have no bedding structure and to have OSL heterogeneity similar to that shown from the bioturbated Texan and Florida sites. The Kalahari linear dunes could therefore have undergone hitherto undetected post-depositional sediment disturbance which would have implications I-or the established OSL chronology for the region. (c) 2006 Elsevier B.V All rights reserved.
引用
收藏
页码:5 / 19
页数:15
相关论文
共 54 条
[41]  
Scott T. M, 2001, TEXT ACCOMPANY GEOLO
[42]  
SELLARDS EH, 1932, GEOLOGY TEXAS, V1
[43]   Transition-matrix model of bioturbation and radionuclide diagenesis [J].
Shull, DH .
LIMNOLOGY AND OCEANOGRAPHY, 2001, 46 (04) :905-916
[44]   Multiple episodes of aridity in southern Africa since the last interglacial period [J].
Stokes, S ;
Thomas, DSG ;
Washington, R .
NATURE, 1997, 388 (6638) :154-158
[45]   Late Pleistocene wetting and drying in the NW Kalahari: an integrated study from the Tsodilo Hills, Botswana [J].
Thomas, DSG ;
Brook, G ;
Shaw, P ;
Bateman, M ;
Appleton, C ;
Nash, D ;
McLaren, S ;
Davies, F .
QUATERNARY INTERNATIONAL, 2003, 104 :53-67
[46]   Late Quaternary environmental change in central southern Africa: new data, synthesis, issues and prospects [J].
Thomas, DSG ;
Shaw, PA .
QUATERNARY SCIENCE REVIEWS, 2002, 21 (07) :783-797
[47]   Dune activity as a record of late Quaternary aridity in the Northern Kalahari: new evidence from northern Namibia interpreted in the context of regional arid and humid chronologies [J].
Thomas, DSG ;
O'Connor, PW ;
Bateman, MD ;
Shaw, PA ;
Stokes, S ;
Nash, DJ .
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY, 2000, 156 (3-4) :243-259
[48]  
THOMSA V, 1994, VALLEY BRANCH PROJEC, P167
[49]   Bioturbation and Holocene sediment accumulation fluxes in the north-east Atlantic Ocean (Benthic Boundary Layer experiment sites) [J].
Thomson, J ;
Brown, L ;
Nixon, S ;
Cook, GT ;
MacKenzie, AB .
MARINE GEOLOGY, 2000, 169 (1-2) :21-39
[50]   Subterranean ant nests: trace fossils past and future? [J].
Tschinkel, WR .
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY, 2003, 192 (1-4) :321-333