HR: 11:35h
AN: PP52A-06    [Abstracts]
TI: The role of tropics in climatic change: Variations in productivity and intermediate waters ventilation to resolve propagation of millennial time-scales in the Eastern Tropical Pacific
AU: * Arellano Torres, E
EM: E.Arellano-Torres@sms.ed.ac.uk
AF: University of Edinburgh, Grant Institute, West Main Road, Edinburgh, EH93JW, United Kingdom
AU: Ganeshram, R S
EM: R.Ganeshram@ed.ac.uk
AF: University of Edinburgh, Grant Institute, West Main Road, Edinburgh, EH93JW, United Kingdom
AB: A 40 metre Calypso piston core (MD02-2519) was raised from the Mazatlán margin off NW Mexico (22° 30.89N / 106° 39.00W; 995 m water depth) is used to reconstruct millennial scale oscillation in eastern Tropical North Pacific over the last 130Ka. We have reconstructed proxy records of productivity (% organic carbon, reflectivity, δ13C in OC & opal) and denitrification (δ15N) in very high resolution. These records show that the accumulation of biogenic components and denitrification declined during Dansgaard-Oescheger (D/O) stadials and glacial periods, but are higher during warm and interglacial periods. Thus, millenial scale records in this area are similar to records off Southern California and Santa Barbara Basin. The underlying cause for changes in denitrification in this area will be scrutinized using additional proxy records off benthic foraminiferal δ13C and assemblage changes recording intermediate water circulation/ventilation changes. These new records will be compared with existing records from the ETP to address (1) whether millennial scale oscillations in the Pacific originate at low or high latitudes and (2) whether these oscillations first propagated in the study site through the ocean (intermediate water circulation/ventilation) or through the atmosphere (upwelling/productivity).
DE: 3344 Paleoclimatology (0473, 4900)
DE: 4279 Upwelling and convergences (4964)
DE: 4850 Marine organic chemistry (0470, 1050)
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 8408 Volcano/climate interactions (1605, 3309)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Joint Assembly