DOI: 10.1016/j.quascirev.2014.05.005
Scopus记录号: 2-s2.0-84901818219
论文题名: Variations in water level for Lake Turkana in the past 8500 years near Mt. Porr, Kenya and the transition from the African Humid Period to Holocene aridity
作者: Forman S.L. ; Wright D.K. ; Bloszies C.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2014
卷: 97 起始页码: 84
结束页码: 101
语种: 英语
英文关键词: Holocene
; Lake level
; Lake turkana
; Monsoon variability
; Relict beaches
Scopus关键词: Atmospheric thermodynamics
; Beaches
; Oceanography
; Quartz
; Stratigraphy
; Water levels
; Holocenes
; Hydrological process
; Lake level fluctuations
; Lake levels
; Monsoon variability
; Quartz grains
; Sea surface temperatures
; Western indian oceans
; Lakes
; aridity
; carbon isotope
; compression
; Holocene
; humid environment
; intertropical convergence zone
; paleoclimate
; Postglacial
; sea surface temperature
; water level
; Atlantic Ocean
; East African Lakes
; Indian Ocean
; Lake Turkana
英文摘要: A stratigraphic and geomorphic study of relict beaches up to 80m above current water level of Lake Turkana reveal four major lake level fluctuations of >50m between ca 8.5 and 4.5ka during the transition from the African Humid Period to Holocene aridity. We hypothesize that high stands of Lake Turkana reflect complex hydrological processes with variability in Atlantic and Indian Ocean-derived moisture into East Africa, ultimately linked to changes in sea surface temperatures (SSTs). Lake level rise was also amplified regionally by increased precipitation causing overflow from the adjacent Suguta and Chew Bahir basins, particularly during high stands at ca >8.5ka and at 6.4ka. The timing of transgressive and regressive events is constrained by 14C dating of carefully selected lacustrine mollusks, incorporation of previous shell ages with sufficient elevational control, and OSL dating of quartz grains from littoral and sublittoral deposits by a multiple aliquot regeneration (MAR) approach. There was a high water level up to at least 70m at >8.5ka that probably reached the spillover limit ~100m. A brief (<500yr) high stand up to at least 50m at ca 7ka appears to be coincident with warm postglacial SSTs in the western Indian Ocean and thus may reflect a strengthened East African Monsoon, though some precipitation was probably derived from Atlantic sources as well. A pronounced high stand inferred at ca 6.4ka, possibly up to 100m, is associated with warming across the Indian Ocean and equatorward compression of the ITCZ, thus reflecting a strengthened East African Monsoon. A high stand occurred at ca 5.5-5.0ka up to at least 80m, with a precipitous drop in lake level by 4.6ka. Evidence from relict Porr strand plain indicate that lake level was probably below 20m since ca 4.5ka, though there were two noticeable high stands up to 12-20m at ca 830 years ago and <100 years, the latter age is consistent with the historic record. © 2014 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/60214
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Geology, Baylor University, One Bear Place #97354, Waco, TX 76796, United States; Department of Archaeology and Art History, Seoul National University, San 56-1, Sillim-9dong, Gwanak-gu, Seoul 151-745, South Korea; Department of Earth and Environmental Sciences, University of Illinois at Chicago, Chicago, IL 60607, United States
Recommended Citation:
Forman S.L.,Wright D.K.,Bloszies C.. Variations in water level for Lake Turkana in the past 8500 years near Mt. Porr, Kenya and the transition from the African Humid Period to Holocene aridity[J]. Quaternary Science Reviews,2014-01-01,97