DOI: 10.1016/j.quascirev.2014.01.021
Scopus记录号: 2-s2.0-84896811791
论文题名: Proglacial lake sediment records reveal Holocene climate changes in the Venezuelan Andes
作者: Stansell N.D. ; Polissar P.J. ; Abbott M.B. ; Bezada M. ; Steinman B.A. ; Braun C.
刊名: Quaternary Science Reviews
ISSN: 2773791
出版年: 2014
卷: 89 起始页码: 44
结束页码: 55
语种: 英语
英文关键词: Clastic sediment flux
; Little Ice Age
; Middle Holocene
; Northern tropics
; Paleoclimate
Scopus关键词: Clastic sediments
; Holocenes
; Little Ice Age
; Northern tropics
; Paleoclimates
; Climate change
; Driers (materials)
; Glacial geology
; Ice
; Lakes
; Landforms
; Tropics
; Watersheds
; Sediments
; clastic sediment
; climate variation
; glacier advance
; glacier dynamics
; glacier retreat
; Holocene
; hypsometry
; lacustrine deposit
; lake level
; paleoclimate
; precipitation (climatology)
; proglacial environment
; sediment transport
; watershed
; Andes
; Cordillera de Merida
; Venezuela
英文摘要: Lake sediment records from the Cordillera de Mérida in the northern Venezuelan Andes document the history of local glacial variability and climate changes during the Holocene (~12ka to the present). The valleys that contain these lakes have similar bedrock compositions and hypsometries, but have different headwall elevations and aspects, which makes them useful for investigating the magnitude of past glaciations. There was widespread glacial retreat in the Venezuelan Andes during the early Holocene, after which most watersheds remained ice free, and thus far only valleys with headwalls higher than ~4400masl contain evidence of glaciation during the last ~10ka. There was a pronounced shift in sediment composition for the Montos (headwall: ~4750masl) and Los Anteojos (headwall: ~4400masl) records during the middle Holocene from ~8.0 to 7.7ka when conditions appear to have become ice free and drier. There is tentative evidence that the glacier in the Mucubají valley (headwall: ~4609masl) advanced from ~8.1 to 6.6ka and then retreated during the latter stages of the middle Holocene. Clastic sediment accumulation in other nearby lake basins was either low or decreased throughout most of the middle Holocene as watersheds stabilized under warmer and/or drier conditions. In the Montos record, there was another major shift in sediment composition that occurred from ~6.5 to 5.7ka, similar to other regional records that suggest conditions were drier during this period. Overall, the late Holocene was a period of warmer and wetter conditions with ice extent at a minimum in the northern tropical Andes. There were also punctuated decadal to multi-centennial periods of higher clastic sediment accumulation during the last ~4ka, likely in response to periods of cooling and/or local precipitation changes. In watersheds with headwalls above 4600masl, there is evidence of glacial advances during the Little Ice Age (~0.6-0.1ka). The pattern of glacial variability is generally similar in both the northern and southern tropics during the Little Ice Age, suggesting that ice margins in both regions were responding to colder and wetter conditions during the latest Holocene. The observed pattern of Holocene climate variability in the Venezuelan Andes cannot be explained by insolation forcing alone, and tropical ocean influences were likely associated with the observed glacial and lake level changes. © 2014 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/60350
Appears in Collections: 过去全球变化的重建
There are no files associated with this item.
作者单位: Department of Geology and Environmental Geosciences, Northern Illinois University, 312 Davis Hall, Normal Road, DeKalb, IL 60115, United States; Lamont-Doherty Earth Observatory of Columbia University, 61 Route 9W, Palisades, NY 10964, United States; Department of Geology and Planetary Science, University of Pittsburgh, 4107 O'Hara Street, Pittsburgh, PA 15260, United States; Departamento de Ciencias de la Tierra, Universidad Pedagógica Experimental Libertador, Av. Páez, El Paraíso, Caracas 1021, Venezuela; Department of Meteorology and Earth and Environmental Systems Institute, Pennsylvania State University, 528 Walker Building, University Park, PA 16802-5013, United States; Department of Geography and Regional Planning, Westfield State University, Westfield, MA 01086, United States
Recommended Citation:
Stansell N.D.,Polissar P.J.,Abbott M.B.,et al. Proglacial lake sediment records reveal Holocene climate changes in the Venezuelan Andes[J]. Quaternary Science Reviews,2014-01-01,89