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Vegetation and climate near Lago Llanquihue in the Chilean Lake District between 20200 and 9500 14 C yr BP
Author(s) -
Moreno Patricio I.
Publication year - 1997
Publication title -
journal of quaternary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.142
H-Index - 94
eISSN - 1099-1417
pISSN - 0267-8179
DOI - 10.1002/(sici)1099-1417(199711/12)12:6<485::aid-jqs330>3.0.co;2-4
Subject(s) - nothofagus , westerlies , southern hemisphere , radiocarbon dating , geology , glacial period , holocene , physical geography , pollen , ecology , climatology , geography , oceanography , biology , paleontology
Radiocarbon‐dated pollen records of two adjacent sediment cores from Canal de la Puntilla (40°57′09″S, 72°54′18″W) in the Chilean Lake District reveal that a sparsely vegetated landscape prevailed during the portion of the Last Glacial Maximum between 20200 and about 14800 14 C yr BP. Dominating the vegetation was Nothofagus , Gramineae and Compositae, along with taxa commonly found today above the Andean treeline ( Perezia ‐type, Valeriana ) and in Magellanic Moorlands ( Donatia, Astelia ). Nothofagus expanded between 20200 and 15800 14 C yr BP, interrupted by a reversal at 19200 14 C yr BP and followed by a prominent increase in Gramineae pollen between 15800 and about 14800 14 C yr BP. A major increase in Nothofagus started at about 14800 14 C yr BP, followed by an abrupt expansion of thermophilous Valdivian/North Patagonian Rain Forest taxa ( Myrtaceae, Lomatia/Gevuina, Hydrangea , etc.) at about 14000 14 C yr BP. An opening of the rain forest and an expansion of Podocarpus nubigena, Misodendrum , and Maytenus disticha ‐type subsequently occurred between 11000 and 10000 14 C yr BP. These results suggest that mean annual temperature was 6–7°C colder than at present, with twice the modern annual precipitation between 20200 and 14000 14 C yr BP, implying a northward shift and intensification of the westerlies storm‐tracks. Slight climate warming occurred between 20200 and 15800 14 C yr BP, featuring cooling reversals at 19200 14 C yr BP, and later at 15800 14 C yr BP. The warming of the last termination started at about 14800 14 C yr BP, and reached a total temperature rise of ≥5°C by 12400 14 C yr BP, followed by cooling between 11000 and 10000 14 C yr BP. © 1997 John Wiley & Sons, Ltd.