DOI: 10.1016/j.palaeo.2012.11.013
论文题名: Late Holocene air temperature variability reconstructed from the sediments of Laguna Escondida, Patagonia, Chile (45°30'S)
作者: Elbert J. ; Wartenburger R. ; von Gunten L. ; Urrutia R. ; Fischer D. ; Fujak M. ; Hamann Y. ; Greber N.D. ; Grosjean M.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2013
卷: 369 起始页码: 482
结束页码: 492
语种: 英语
英文关键词: Climate change
; Paleoclimatology
; Quaternary
; Sedimentology
; South America
; Tephra
英文摘要: Climate and environmental reconstructions from natural archives are important for the interpretation of current climatic change. Few quantitative high-resolution reconstructions exist for South America which is the only land mass extending from the tropics to the southern high latitudes at 56°S. We analyzed sediment cores from two adjacent lakes in Northern Chilean Patagonia, Lago Castor (45°36'S, 71°47'W) and Laguna Escondida (45°31'S, 71°49'W). Radiometric dating (210Pb, 137Cs, 14C-AMS) suggests that the cores reach back to c. 900BC (Laguna Escondida) and c. 1900BC (Lago Castor). Both lakes show similarities and reproducibility in sedimentation rate changes and tephra layer deposition. We found eight macroscopic tephras (0.2-5.5cm thick) dated at 1950BC, 1700BC, at 300BC, 50BC, 90AD, 160AD, 400AD and at 900AD. These can be used as regional time-synchronous stratigraphic markers. The two thickest tephras represent known well-dated explosive eruptions of Hudson volcano around 1950 and 300BC. Biogenic silica flux revealed in both lakes a climate signal and correlation with annual temperature reanalysis data (calibration 1900-2006AD; Lago Castor r=0.37; Laguna Escondida r=0.42, seven years filtered data). We used a linear inverse regression plus scaling model for calibration and leave-one-out cross-validation (RMSEv=0.56°C) to reconstruct sub decadal-scale temperature variability for Laguna Escondida back to AD 400. The lower part of the core from Laguna Escondida prior to AD 400 and the core of Lago Castor are strongly influenced by primary and secondary tephras and, therefore, not used for the temperature reconstruction. The temperature reconstruction from Laguna Escondida shows cold conditions in the 5th century (relative to the 20th century mean), warmer temperatures from AD 600 to AD 1150 and colder temperatures from AD 1200 to AD 1450. From AD 1450 to AD 1700 our reconstruction shows a period with stronger variability and on average higher values than the 20th century mean. Until AD 1900 the temperature values decrease but stay slightly above the 20th century mean. Most of the centennial-scale features are reproduced in the few other natural climate archives in the region. The early onset of cool conditions from c. AD 1200 onward seems to be confirmed for this region. © 2012 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/69911
Appears in Collections: 过去全球变化的重建
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作者单位: University of Bern, Oeschger Centre for Climate Change Research and Institute of Geography, University of Bern, Bern, Switzerland; PAGES International Project Office, Bern, Switzerland; Centro de Ciencias Ambientales EULA-Chile, Universidad de Concepción, Concepción, Chile; SURF-EAWAG, Duebendorf, Switzerland; Geological Institute, ETH Zurich, Zurich, Switzerland; Institute of Geological Sciences, University of Bern, Bern, Switzerland
Recommended Citation:
Elbert J.,Wartenburger R.,von Gunten L.,et al. Late Holocene air temperature variability reconstructed from the sediments of Laguna Escondida, Patagonia, Chile (45°30'S)[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2013-01-01,369