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1	An Investigation of Stratigraphic Evidence for an Abrupt Climatic Event 8200 yr BP in Valle de las Morrenas, Costa Rica Watson, Brian Thomas 01 May 2011 (has links) Lago de las Morrenas 4 (9.498056° [degrees] N, 83.486111° [degrees] W, 3466 m elev.) is the lowest lake in a chain of glacial lakes located in the Valle de las Morrenas, a valley facing almost due north from Cerro Chirripó, the highest peak in the Cordillera de Talamanca in Costa Rica. Coarse resolution analyses of pollen, microscopic charcoal, and loss-on-ignition of a ca. 10,000 year sediment record from Lago de las Morrenas 4 was carried out to complement and extend previous research on the environmental history of the Chirripó highlands and to provide context for high-resolution sampling and analysis of early Holocene sediments. The focus of the high-resolution analysis was the period around 8200 cal yr BP, the time of a prominent Holocene climatic event recognized at many northern hemisphere sites between ca. 8000 and 8400 cal yr BP. The high-resolution sampling of sediments encompassing the time period of the 8200 yr BP event revealed a sharp increase in microscopic charcoal indices coincident with a shift from fibrous silty organic sediment to granular peat. These shifts, which occurred ca. 7900 cal yr BP, are interpreted to reflect an interval of drier climate and lower lake level. A decrease in Poaceae pollen percentages and an increase in Alnus pollen from montane forests may reflect reduced pollen production within the páramo at this time. The peak charcoal concentration and influx value at ca. 7800 cal yr BP in the Morrenas 4 record may match a similar peak in the macroscopic charcoal record from nearby Morrenas 1 that occurred ca. 8000 cal yr BP. Both peaks may correspond to the 8200 yr BP event. Paramo 8.2ka Palynology Paleoecology Paleoenvironmental Other Earth Sciences Other Ecology and Evolutionary Biology Physical and Environmental Geography
2	Stable isotope investigations on speleothems from different cave systems in Germany. / Stabile Isotopen-Untersuchungen an Speläothemen aus verschiedenen Höhlensystemen in Deutschland. Nordhoff, Peter 13 June 2005 (has links) No description available. 550 Geowissenschaften VAO 200 VDI 200 VDI 210 VDI 220 VEB 127 VEB 147 VJJ 100 Mathematics and Natural Science Speläotheme Stalagmiten Stalaktiten Tropfwasser Deutschland Schwäbische Alb Fränkische Alb Harz Paläoklima δ18O/δ13C stabile Isotope 234U/230Th TIMS Zaininger Höhle Hintere Kohlhaldenhöhle Baumannshöhle Herrmannshöhle Mühlbachquellhöhle Höhlenruine Hunas thermodynamische Equilibrium kinetische Fraktionierung OIS2 Jüngere Dryas Bölling/Alleröd T1 Pleistozän Holozän 8.2ka Holozänes Optimum speleothem stalagmites stalactites dripwater Germany Swabian Alb Franconian Alb Harz Mountains paleoclimate δ18O/δ13C stable isotopes 234U/230Th TIMS Zaininger Cave Hintere Kohlhalden Cave Baumanns-Cave Herrmanns-Cave Mühlbach-Cave Paleocave Hunas hendy test equilibrium conditions kinetic fractionation OIS2 Younger Dryas Bölling/Alleröd T1 Pleistocene Holocene 8.2 kyr. Holocene Climatic Optimum 38.03 38.82 38.17 38.19 38.32

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An Investigation of Stratigraphic Evidence for an Abrupt Climatic Event 8200 yr BP in Valle de las Morrenas, Costa Rica

Stable isotope investigations on speleothems from different cave systems in Germany. / Stabile Isotopen-Untersuchungen an Speläothemen aus verschiedenen Höhlensystemen in Deutschland.