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DOI	10.1016/j.quascirev.2019.07.040
	Geological and soil maps of the Palaeo-Agulhas Plain for the Last Glacial Maximum
	Cawthra H.C.; Cowling R.M.; Andò S.; Marean C.W.
发表日期	2020
ISSN	0277-3791
卷号	235
英文摘要	The South African Cape South Coast is bordered by one of the broadest continental shelves in Africa. The Agulhas Bank, inshore shelf and presently exposed coastal plain make up the Palaeo-Agulhas Plain (PAP), though our area of study extends beyond this limit and as far inland as the first mountain belt. Quaternary sea levels have been significantly lower than at present for ∼90% of the Pleistocene, exposing a terrestrial ecosystem on what is now the submerged shelf. The presently drowned component makes up 94% of the total area of the PAP. Past work has hypothesised a contrast in character of this submerged landscape when compared to the subaerial environment. Here, we assimilate newly-acquired geophysical and geological datasets to produce geological- and soil maps from the Last Glacial Maximum on a scale of 1:750,000, covering an area of ∼55,000 km. Three broad geomorphic zones are defined, including the Western section from Cape Agulhas to Cape Infanta, the Central section from Cape Infanta to Knysna and the Eastern section extending eastward of Knysna. We demonstrate that Mesozoic sedimentary deposits crop out near the surface on this current-swept shelf and soils derived from siltstone and shale bedrock are prominent when the coast is up to 64 km distant from the modern shoreline at its maximum point. Beyond this, weathered limestone dominates the substrate sequences on the Agulhas Bank. We show that the submerged landscape was a unique terrestrial environment and that there is no exact modern-day analogue in the region other than a small (∼70 km2) area located at the edge of the Agulhas Plain near Cape Agulhas, and map major contrasts in the geological, topographic and edaphic nature of the landscape from the onshore to the offshore. The expansion of this plain is coupled with exaggerated floodplains, meandering shallowly incised rivers and wetlands. The submerged shelf is dominated by fertile soils compared to the dissected onshore belt, and extensive calcareous dunefields extending up to 10 km inland from their associated palaeoshorelines covered much of the emergent shelf. Sedimentary bedforms may have obstructed or slowed drainage as suggested by leached palaeosols and carbonate mixing observed in petrographic thin sections and grain mounts. The data show a low-relief “plains” landscape, which contrasts strongly to the topographically complex contemporary coastal foreland. © 2019 Elsevier Ltd
英文关键词	Cape south coast; Marine geology; Palaeolandscape; Pleistocene geological map; Pleistocene soil map; South Africa; Submerged landscape
语种	英语
scopus关键词	Glacial geology; Lime; Offshore oil well production; Rivers; Sea level; Sedimentology; Submarine geology; Geological map; Palaeolandscape; Soil maps; South Africa; Submerged landscape; Underwater soils; bedrock; coastal plain; continental shelf; floodplain; Last Glacial Maximum; limestone; Pleistocene; Quaternary; siltstone; terrestrial environment; Agulhas Bank; Agulhas Plain; Cape Agulhas; Indian Ocean; South Africa; Western Cape
来源期刊	Quaternary Science Reviews
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/151518
作者单位	Geophysics and Remote Sensing Unit, Council for Geoscience Western Cape Office, PO Box 572, Bellville, 7535, South Africa; African Centre for Coastal Palaeoscience, Nelson Mandela University, PO Box 77000, Port Elizabeth, Eastern Cape 6031, South Africa; Department of Earth and Environmental Sciences, University of Milano Bicocca, PO Box 20126, Piazza della Scienza 4, Milan, Italy; Institute of Human Origins, School of Human Evolution and Social Change, Arizona State University, PO Box 872402, Tempe, AZ 85287-2402, United States
推荐引用方式 GB/T 7714	Cawthra H.C.,Cowling R.M.,Andò S.,et al. Geological and soil maps of the Palaeo-Agulhas Plain for the Last Glacial Maximum[J],2020,235.
APA	Cawthra H.C.,Cowling R.M.,Andò S.,&Marean C.W..(2020).Geological and soil maps of the Palaeo-Agulhas Plain for the Last Glacial Maximum.Quaternary Science Reviews,235.
MLA	Cawthra H.C.,et al."Geological and soil maps of the Palaeo-Agulhas Plain for the Last Glacial Maximum".Quaternary Science Reviews 235(2020).