Northeastern Pacific oxygen minimum zone variability over the past 70 kyr; impact of biological production and oceanic ventilation

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doi: 10.1029/2011PA002126
Author(s): Cartapanis, Olivier; Tachikawa, Kazuyo; Bard, Edouard
Author Affiliation(s): Primary:
CNRS-IRD-College de France-Aix en Provence Université, CEREGE, Aix en Provence, France
Volume Title: Paleoceanography
Source: Paleoceanography, 26(4). Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0883-8305 CODEN: POCGEP
Note: In English. 96 refs.; illus., incl. 1 table, sketch maps
Summary: During the last glacial period, the Oxygen Minimum Zone (OMZ) within the northeastern Pacific Ocean strengthened and weakened on a millennial time scale, demonstrating a tight linkage with northern high latitude climate, although the precise mechanisms responsible remain unknown. Core MD02-2508, retrieved off Baja California, was analyzed for major and trace elements (Br, Ca, Ti, Fe, Mn, and Sr) using a XRF scanner and redox-sensitive trace elements (Cu, Ni, Cd, As, V, Cr, Mo, and U) using the ICP-MS. The trace element content, the Fe/Ti ratio, and Br-based organic carbon exhibit higher values during the Holocene and during warm Dansgaard-Oeschger events than during the Last Glacial Maximum (LGM), stadials, and Heinrich (H) events. A principal component analysis of the element/Al ratio indicated that the following two main factors controlled the chemical composition of the sediments: (1) export production, as represented by organic carbon, that was lower during cold periods; and (2) regional intermediate water oxygenation, as represented by U and Mo variability, that was not supported by a change in export production. The latter suggests that intermediate water oxygenation improved during H events, but slightly deteriorated during late Marine Isotope Stage (MIS) 3 and MIS 2. A local biogeochemical effect, forced by atmospheric processes, impacted the LGM and H events in the same manner. Whereas regional intermediate oceanic circulation varied in an opposite manner during the LGM and H events, possibly as a result of the global reorganization of intermediate water circulation during the LGM.
Year of Publication: 2011
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 07 Marine Geology and Oceanography; Actinides; Baja California; Biochemistry; Carbon; Cenozoic; Chlorophyll; Climate; Dansgaard-Oeschger cycles; Dissolved oxygen; East Pacific; Geochemistry; Heinrich events; Holocene; ICP mass spectra; Isotope ratios; Isotopes; Last glacial maximum; Leg 146; Leg 167; Mass spectra; Metals; Mexico; Molybdenum; North Pacific; Northeast Pacific; O-18/O-16; ODP Site 1017; ODP Site 893; Ocean Drilling Program; Ocean circulation; Organic carbon; Organic compounds; Oxygen; Oxygen minimum zone; Pacific Ocean; Paleo-oceanography; Paleoclimatology; Pigments; Pleistocene; Porphyrins; Principal components analysis; Productivity; Quaternary; Santa Barbara Basin; Sediments; Solutes; Spectra; Stable isotopes; Statistical analysis; Upper Pleistocene; Uranium; X-ray fluorescence spectra
Coordinates: N343205 N343205 W1210625 W1210625
N341715 N341715 W1200211 W1200212
N220000 N320000 W1090000 W1190000
Record ID: 2014039631
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