Lueer, Vanessa et al. (2008): Late Quaternary radiolarian assemblages as indicators of paleoceanographic changes north of the subtropical front, offshore eastern New Zealand, Southwest Pacific

Leg/Site/Hole:
ODP 181
ODP 181 1123
ODP 181 1124
Identifier:
2008-120599
georefid

Creator:
Lueer, Vanessa
University of Bremen, Faculty of Geosciences, Bremen, Federal Republic of Germany
author

Hollis, Christopher J.
GNS Science, New Zealand
author

Willems, Helmut
GNS Science, New Zealand
author

Identification:
Late Quaternary radiolarian assemblages as indicators of paleoceanographic changes north of the subtropical front, offshore eastern New Zealand, Southwest Pacific
2008
In: Lazarus, David B. (editor), Hollis, Christopher J. (editor), Radiolarians in paleoceanography; selected papers from InterRad XI
American Museum of Natural History, New York, NY, United States
54
1
49-69
Abundant and diverse polycystine radiolarian faunas from ODP Leg 181, Site 1123 (0-1.2 Ma at nearly equal 21 kyr resolution) and Site 1124 (0-0.6 Ma, nearly equal 5 kyr resolution, with a disconformity between 0.42-0.22 Ma) have been used to infer Pleistocene-Holocene paleoceanographic changes north of the Subtropical Front (STF), offshore eastern New Zealand, southwest Pacific. The abundance of warm-water taxa relative to cool-water taxa was used to determine a radiolarian paleotemperature index, the Subtropical (ST) Index. ST Index variations show strong covariance with benthic foraminifera oxygen isotope records from Site 1123 and exhibit similar patterns through Glacial-Interglacial (G-I) cycles of marine isotope stages (MIS)15-1. At Site 1123, warm-water taxa peak in abundance during Interglacials (reaching nearly equal 8% of the total fauna). Within Glacials cool-water taxa increase to nearly equal 15% (MIS2) of the fauna. Changes in radiolarian assemblages at Site 1124 indicate similar but much better resolved trends through MIS15-12 and 7-1. Pronounced increases in warm-water taxa occur at the onset of Interglacials (reaching nearly equal 15% of the fauna), whereas the abundance of cool-water taxa increases in Glacials peaking in MIS2 ( nearly equal 17% of the fauna). Overall warmer conditions at Site 1124 during the last 600 kyrs indicate sustained influence of the subtropical, warm East Cape Current (ECC). During Interglacials radiolarian assemblages suggest an increase in marine productivity at both sites which might be due to predominance of micronutrient-rich Subtropical Water. At Site 1123, an increased abundance of deep-dwelling taxa in MIS 13 and 9 suggests enhanced vertical mixing. During Glacials, reduced vigor of ECC flow combined with northward expansion of cool, micronutrient-poor Subantarctic Water occurs. Only at Site 1123 there is evidence of a longitudinal shift of the STF, reaching as far north as 41 degrees S.
English
Coverage:Geographic coordinates:
North:-39.2954
West:-176.3154East: -171.2956
South:-41.4710

Quaternary geology; assemblages; Cenozoic; faunal list; Holocene; Invertebrata; Leg 181; marine environment; microfossils; Ocean Drilling Program; ODP Site 1123; ODP Site 1124; Pacific Ocean; paleo-oceanography; paleobathymetry; paleoclimatology; paleoenvironment; paleotemperature; Pleistocene; Protista; Quaternary; Radiolaria; South Pacific; Southwest Pacific; statistical analysis; West Pacific;

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