DOI: 10.1016/j.gloplacha.2017.01.007
论文题名: Palaeoenvironments during a terminal Oligocene or early Miocene transgression in a fluvial system at the southwestern tip of Africa
作者: Roberts D.L. ; Neumann F.H. ; Cawthra H.C. ; Carr A.S. ; Scott L. ; Durugbo E.U. ; Humphries M.S. ; Cowling R.M. ; Bamford M.K. ; Musekiwa C. ; MacHutchon M.
刊名: Global and Planetary Change
ISSN: 0921-8181
出版年: 2017
卷: 150 起始页码: 1
结束页码: 23
语种: 英语
英文关键词: 3D landscape reconstruction
; Biostratigraphy
; Coastal environment
; Marine transgression
; Palaeoecology
; Southern Africa
; Terminal Oligocene/early Miocene
Scopus关键词: Biostratigraphy
; Catchments
; Ecology
; Plants (botany)
; Rain
; Sea level
; Seismology
; Coastal environments
; Landscape reconstruction
; Marine transgression
; Oligocene
; Palaeoecology
; Southern Africa
; Forestry
; Araucariaceae
; Brachystegia
; Combretaceae
; Dinophyceae
; Filicophyta
; Impagidinium
; Magnoliophyta
; Podocarpaceae
; Rhizophoraceae
英文摘要: A multi-proxy study of an offshore core in Saldanha Bay (South Africa) provides new insights into fluvial deposition, ecosystems, phytogeography and sea-level history during the late Paleogene-early Neogene. Offshore seismic data reveal bedrock topography, and provide evidence of relative sea levels as low as − 100 m during the Oligocene. 3D landscape reconstruction reveals hills, plains and an anastomosing river system. A Chattian or early Miocene age for the sediments is inferred from dinoflagellate taxa Distatodinium craterum, Chiropteridium lobospinosum, Homotryblium plectilum and Impagidinium paradoxum. The subtropical forest revealed by palynology includes lianas and vines, evergreen trees, palms and ferns, implying higher water availability than today, probably reduced seasonal drought and stronger summer rainfall. From topography, sedimentology and palynology we reconstruct Podocarpaceae-dominated forests, Proto-Fynbos, and swamp/riparian forests with palms and other angiosperms. Rhizophoraceae present the first South African evidence of Palaeogene/Neogene mangroves. Subtropical woodland-thicket with Combretaceae and Brachystegia (Peregrinipollis nigericus) probably developed on coastal plains. Some of the last remaining Gondwana elements on the sub-continent, e.g., Araucariaceae, are recorded. Charred particles signal fires prior to the onset of summer dry climate at the Cape. Marine and terrestrial palynomorphs, together with organic and inorganic geochemical proxy data, suggest a gradual glacio-eustatic transgression. The data shed light on Southern Hemisphere biogeography and regional climatic conditions at the Palaeogene-Neogene transition. The proliferation of the vegetation is partly ascribed to changes in South Atlantic oceanographic circulation, linked to the closure of the Central American Seaway and the onset of the Benguela Current ~ 14 Ma. © 2017 URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85011024036&doi=10.1016%2fj.gloplacha.2017.01.007&partnerID=40&md5=1ccb5478ddc2365f43790775631c16e2
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/11749
Appears in Collections: 全球变化的国际研究计划 气候变化与战略
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作者单位: Department of Geography, University of the Free State, Bloemfontein, South Africa
Recommended Citation:
Roberts D.L.,Neumann F.H.,Cawthra H.C.,et al. Palaeoenvironments during a terminal Oligocene or early Miocene transgression in a fluvial system at the southwestern tip of Africa[J]. Global and Planetary Change,2017-01-01,150.