Vegetation and climate near Lago Llanquihue in the Chilean Lake District between 20200 and 9500 14C yr BP
✍ Scribed by Patricio I. Moreno
- Book ID
- 101283015
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 459 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0267-8179
No coin nor oath required. For personal study only.
✦ Synopsis
Radiocarbon-dated pollen records of two adjacent sediment cores from Canal de la Puntilla (40°57Ј09ЉS, 72°54Ј18ЉW) in the Chilean Lake District reveal that a sparsely vegetated landscape prevailed during the portion of the Last Glacial Maximum between 20 200 and about 14 800 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 20 200 and 15 800 14 C yr BP, interrupted by a reversal at 19 200 14 C yr BP and followed by a prominent increase in Gramineae pollen between 15 800 and about 14 800 14 C yr BP. A major increase in Nothofagus started at about 14 800 14 C yr BP, followed by an abrupt expansion of thermophilous Valdivian/North Patagonian Rain Forest taxa (Myrtaceae, Lomatia/Gevuina, Hydrangea, etc.) at about 14 000 14 C yr BP. An opening of the rain forest and an expansion of Podocarpus nubigena, Misodendrum, and Maytenus disticha-type subsequently occurred between 11 000 and 10 000 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 20 200 and 14 000 14 C yr BP, implying a northward shift and intensification of the westerlies storm-tracks. Slight climate warming occurred between 20 200 and 15 800 14 C yr BP, featuring cooling reversals at 19 200 14 C yr BP, and later at 15 800 14 C yr BP. The warming of the last termination started at about 14 800 14 C yr BP, and reached a total temperature rise of Ն5°C by 12 400 14 C yr BP, followed by cooling between 11 000 and 10 000 14 C yr BP.