| Title | Timing of the late glacial and Younger Dryas cold reversal in southern Chile varved sediments |
| Author | Boës, X.; Fagel, N. |
| Author Affil | Boës, X., University of Liège, Clays and Paleoclimate Research Unit, Liege, Belgium. Other: University of Liège, Belgium; Université Catholique de Louvain, Belgium; Eidgenössische Technische Hochschule Zürich, Switzerland |
| Source | A 17,900-year multi-proxy lacustrine record of Lago Puyehue (Chilean Lake District), edited by M. De Batist, N. Fagel, M. Loutre and E. Chapron. Journal of Paleolimnology, 39(2), p.267-281, . Publisher: Springer, Dordrecht, Netherlands. ISSN: 0921-2728 |
| Publication Date | Feb. 2008 |
| Notes | In English. 46 refs. GeoRef Acc. No: 297025. CRREL Acc. No: 64001977 |
| Index Terms | lacustrine deposits; lake deposits; paleoclimatology; Pleistocene; Quaternary deposits; sediments; Antarctica--Byrd Station; Caribbean Sea--Cariaco Basin; Chile-- Lake District; Greenland--Summit; Antarctica; Arctic region; Atlantic Ocean; Byrd Station; Cariaco Basin; Caribbean Sea; Cenozoic; Chile; cores; deglaciation; GISP2; Greenland; lacustrine environment; Lago Puyehue; Lake District; lake sediments; lithostratigraphy; Marie Byrd Land; North Atlantic; paleoenvironment; planar bedding structures; Quaternary; sedimentary structures; South America; Summit Greenland; upper Pleistocene; upper Weichselian; varves; Weichselian; Younger Dryas |
| Abstract | The timing of the last deglaciation in southern Chile is re-evaluated from a calendar varve chronology (Lago Puyehue, 40°S). The climate shifts are analysed by continuous annual varve-thickness measurements through the 17,100 cal. year to 10,800 cal. year BP time window. The varve years are determined by the alternation of light (phytoplankton-rich) and dark (terrigenous and organic-rich) layers forming graded annual couplets. The varve chronology is constructed by conventional varve-counting methods on thin sections after correction for instantaneous volcanic and/or seismic events detected in the thin sections. The calibrated varve-age model derived from the manual varve counting is constrained by high-resolution grey-scale (GS) semi-automatic counts of the annual light phytoplankton-rich layers. Due to physical sediment properties the GS constitutes a proxy record for the phytoplankton/terrigenous varve-thickness variations through the sediment record. The varve couplets are thicker/thinner during humid/dry phases and darker/lighter (negative/positive annual grey-scale index) during cold/warm phases. Our results show that at 40°S the last deglaciation took place in two phases between 17,100 cal. year and 15,500 cal. year BP. (mod. journ. abst.) |
| URL | http://hdl.handle.net/10.1007/s10933-007-9118-x |
| Publication Type | journal article |
| Record ID | 87404 |