DOI: 10.1016/j.quascirev.2014.06.029
Scopus记录号: 2-s2.0-84904353906
论文题名: Understanding late quaternary change at the land-ocean interface: A synthesis of the evolution of the Wilderness coastline, South Africa
作者: Cawthra H.C. ; Bateman M.D. ; Carr A.S. ; Compton J.S. ; Holmes P.J.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2014
卷: 99 起始页码: 210
结束页码: 223
语种: 英语
英文关键词: Aeolianite
; Barriers
; Dunes
; Palaeochannels
; Seismic profiling
Scopus关键词: Deposits
; Sediments
; Seismology
; Stratigraphy
; Aeolianite
; Barriers
; Dunes
; Palaeochannels
; Seismic profiling
; Sea level
; continental shelf
; dune
; geological record
; land-sea interaction
; paleochannel
; Quaternary
; sea level change
; sedimentation rate
; Eastern Cape
; South Africa
; Wild Coast
英文摘要: Coastal barrier systems have been widely used to understand the responses of coastal margins to fluctuating Pleistocene sea levels. What has become apparent, particularly with the development of robust chronological frameworks, is that gaps in terrestrial barrier sedimentary records are not uncommon and that they most likely reflect phases of barrier construction on the now submerged continental shelf. Thus, understanding the land-ocean interface through time is critical to fully appreciate the Quaternary archives contained within the barriers and their associated back-barrier deposits. This study uses offshore and lakefloor (back-barrier) seismic profiling from the South African south coast at Wilderness to link the sub-aerially exposed barrier stratigraphy to the currently submerged geological and sedimentological record. A total of eight separate submerged aeolian units are identified at water depths of up to 130m below mean sea level. Their approximate ages are constrained with reference to the eustatic sea-level record and the deepest units are consistent with the estimated magnitude of sea-level lowering during the Last Glacial Maximum (LGM) on the South African coastline. As previously assumed, aeolian sedimentation tracked the shoreline onto the continental shelf during the Late Pleistocene. During sea-level regressions, both the incision of fluvial channels and the deposition of back-barrier systems occurred across the continental shelf. During late low stand/early transgression periods, landward shoreface migration occurred, pre-existing channel incisions were infilled and pre-existing barriers were truncated. Rapid transgression, however, allowed the preservation of some back-barrier deposits, possibly aided by protection from antecedent topography. As sea level neared the present-day elevation, erosion of the mid-shelf sediments resulted in the development of a Holocene sediment wedge, which was augmented by Holocene fluvial sediment supply. The Holocene sand wedge is preserved in the back-barrier lakes and was deposited during the Holocene highstand inundation. Overlying middle to late Holocene terrestrial muds reflect the deposition of river-borne mud onto the shelf. These results clearly demonstrate that within transgressive-regressive sea-level cycles, accommodation space for barriers is controlled by antecedent drainage systems and gradients on the adjacent inner continental shelf. © 2014 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/60194
Appears in Collections: 过去全球变化的重建
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作者单位: Marine Geoscience Unit, Council for Geoscience, PO Box 572, Bellville 7535, South Africa; Department of Geography, University of Sheffield, Winter Street, Sheffield S10 2TN, United Kingdom; Department of Geography, University of Leicester, University Road, Leicester LE1 7RH, United Kingdom; Department of Geological Sciences, University of Cape Town, Rondebosch 7700, South Africa; Department of Geography, University of the Free State, PO Box 339, Bloemfontein 9300, South Africa
Recommended Citation:
Cawthra H.C.,Bateman M.D.,Carr A.S.,et al. Understanding late quaternary change at the land-ocean interface: A synthesis of the evolution of the Wilderness coastline, South Africa[J]. Quaternary Science Reviews,2014-01-01,99