DOI: 10.1016/j.quascirev.2013.10.031
Scopus记录号: 2-s2.0-84888123621
论文题名: Isotopic reconstruction of the African Humid Period and Congo Air Boundary migration at Lake Tana, Ethiopia
作者: Costa K. ; Russell J. ; Konecky B. ; Lamb H.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2014
卷: 83 起始页码: 58
结束页码: 67
语种: 英语
英文关键词: African Humid Period
; Air mass trajectories
; Compound specific hydrogen isotopes
; Congo Air Boundary
; East Africa
; Holocene paleoclimate
; Tropical paleoclimate
Scopus关键词: Hierarchical systems
; Hydrogen
; Isotopes
; Moisture
; Rain
; Air mass trajectories
; Congo Air Boundary
; East Africa
; Humid periods
; Hydrogen isotope
; Paleoclimates
; Tropical paleoclimate
; Lakes
; Holocene
; humid environment
; isotopic analysis
; leaf
; rainfall
; sediment core
; vegetation dynamics
; Africa
; Ethiopia
; Lake Tana
英文摘要: The African Humid Period of the early to mid-Holocene (12,000-5000 years ago) had dramatic ecological and societal consequences, including the expansion of vegetation and civilization into the "green Sahara." While the humid period itself is well documented throughout northern and equatorial Africa, mechanisms behind observed regional variability in the timing and magnitude of the humid period remain disputed. This paper presents a new hydrogen isotope record from leaf waxes (δDwax) in a 15,000-year sediment core from Lake Tana, Ethiopia (12°N, 37°E) to provide insight into the timing, duration, and intensity of the African Humid Period over northeastern Africa. δDwax at Lake Tana ranges between -80‰ and -170‰, with an abrupt transition from D-enriched to D-depleted waxes between 13,000-11,500 years before present (13-11.5 ka). A similarly abrupt transition from D-depleted to D-enriched waxes occurs ca 8.5-8 ka and is followed by generally D-enriched waxes throughout the late Holocene. Trends in δDwax covary with changes in Northern Hemisphere summer insolation and reflect increased precipitation at Lake Tana during the AHP; however, the transition from D-depleted to D-enriched waxes occurs earlier at Lake Tana (ca8ka, vs5ka) than in many other regional records, and the amplitude of D-depletion during the AHP is larger at Lake Tana as well. We attribute this early enrichment to a reduction of moisture derived from westerly sources (the Congo Basin and Atlantic Ocean) which we suggest are D-depleted relative to moisture sourced from the east (Indian Ocean) and the north (Red Sea and Mediterranean Sea). Our new record highlights the importance of both the northward migration of the tropical rain belt as well as east-west migration of the Congo Air Boundary to precipitation source and amount during the African Humid Period. © 2013 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/60417
Appears in Collections: 过去全球变化的重建
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作者单位: Department of Geological Sciences, Brown University, Box 1846, Providence, RI 02912, United States; Institute of Geography and Earth Sciences, University of Wales, Aberystwyth SY23 3DB, United Kingdom; Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964, United States; School of Earth and Atmospheric Sciences, Georgia Institute of Technology, 311 Ferst Drive, Atlanta, GA 30332-0340, United States
Recommended Citation:
Costa K.,Russell J.,Konecky B.,et al. Isotopic reconstruction of the African Humid Period and Congo Air Boundary migration at Lake Tana, Ethiopia[J]. Quaternary Science Reviews,2014-01-01,83