HR: 08:45h
AN: PP11C-04    [Abstracts]
TI: El Nino Activity During MIS 5e in Peru
AU: * Rein, B
EM: brein@uni-mainz.de
AF: Bert Rein, Johannes Gutenberg - Universitaet Mainz, Institut fuer Geowissenschaften, Becherweg 21, D-55099 Mainz, RHP D-55099 Germany
AU: Sirocko, F
EM: sirocko@uni-mainz.de
AF: Bert Rein, Johannes Gutenberg - Universitaet Mainz, Institut fuer Geowissenschaften, Becherweg 21, D-55099 Mainz, RHP D-55099 Germany
AB: Oceanography and climate along the coast of Peru is fundamentally linked to ENSO variability with stronger lithic flux into the sea and reduced marine bioproductivity during El Nino events. A 19 m long piston core with laminated marine sediments has been recovered on the edge of the Peruvian shelf (12 03'S, 77 40W, 184 m waterdepth) during cruise Sonne-147 in 2000. We present the lower 6 meters of this core that cover the time between 100 to 130 kyr before the present (BP). SST has been estimated from alkenone analysis with a mean temporal resolution of 300 years. Color logging along the core at 2 mm intervals revealed high resolution proxy data (3 to 30 a) for the precipitation on the continent (fine-grained lithics) and marine bioproduction (photosynthesis pigments: chlorines, carotenoids). Proxy data show that a major change occurred around 123 kyr BP. Mean sedimentation rate which is largely controlled by lithics dropped from 40-70 cm/kyr to 18 cm/kyr after 123 kyr BP. Contemporaneously SST start to decline towards the early Glacial level that is reached between 118 to 116 ka during the time of glacial inception. We conclude that stronger El Nino floods occurred before 123 kyr BP and El Ninos were weaker during the second half of MIS 5e. The change to weaker ENSO activity in Peru is therewith roughly contemporaneous with the beginning cooling in Greenland.
UR: http://www.uni-mainz.de/FB/Geo/Geologie/sedi/index.html
DE: 9360 South America
DE: 4267 Paleoceanography
DE: 4522 El Ni¤o
DE: 1600 GLOBAL CHANGE (New category)
DE: 1620 Climate dynamics (3309)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting