Deep-sea benthic foraminiferal record of the mid-Pleistocene transition in the SW Pacific

Author(s): Hayward, Bruce W.; Grenfell, Hugh R.; Sabaa, Ashwaq T.; Sikes, Elizabeth
Author Affiliation(s): Primary:
Geomarine Research, Auckland, New Zealand
Other:
Rutgers, The State University of New Jersey, United States
Volume Title: Early-middle Pleistocene transitions; the land-ocean evidence
Volume Author(s): Head, Martin J., editor; Gibbard, Philip L.
Source: Geological Society Special Publications, Vol.247, p.85-115; Early-middle Pleistocene transitions; the land-ocean evidence, Cambridge, United Kingdom, April 4, 2003, edited by Martin J. Head and Philip L. Gibbard. Publisher: Geological Society of London, London, United Kingdom. ISSN: 0305-8719 CODEN: GSLSBW
Note: In English. Includes appendices. 98 refs.; illus., incl. sect., 2 tables, geol. sketch map
Summary: Benthic foraminiferal faunas from three bathyal sequences provide a proxy record of oceanographic changes through the mid-Pleistocene transition (MPT) on either side of the Subtropical Front (STF), east of New Zealand. Canonical correspondence analyses show that factors related to water depth, latitude and climate cycles were more significant than oceanographic factors in determining changes in faunal assemblage composition over the last 1 Ma. Even so, mid-Pleistocene faunal changes are recognizable and can be linked to inferred palaeoceanographic causes. North of the largely stationary STF the faunas were less variable than to the south, perhaps reflecting the less extreme glacial-interglacial fluctuations in the overlying Substropical Surface Water. Prior to Marine Isotope Stage (MIS) 21 and after MIS 15, the northern faunas had fairly constant composition, but during most of the MPT faunal composition fluctuated in response to climate-related food-supply variations. Faunal changes through the MPT suggest increasing food supply and decreasing dissolved bottom oxygen. South of the STF, beneath Subantarctic Surface Water, mid-Pleistocene faunas exhibited strong glacial-interglacial fluctuations, inferred to be due to higher interglacial nutrient supply and lower oxygen levels. The most dramatic faunal change in the south occurred at the end of the MPT (MIS 15-12), with an acme of Abditodentrix pseudothalmanni, possibly reflecting higher carbon flux and lowered bottom oxygen. This study suggests that the mid-Pleistocene decline and extinction of a group of elongate, cylindrical deep-sea foraminifera may have been related to decreased bottom oxygen concentrations as a result of slower deep-water currents.
Year of Publication: 2005
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Australasia; Benthic taxa; Biostratigraphy; Cenozoic; Climate change; Cluster analysis; Cores; Correlation coefficient; Correspondence analysis; DSDP Site 594; Deep Sea Drilling Project; Dendrograms; Extinction; Faunal list; Foraminifera; Glacial environment; IPOD; Interglacial environment; Invertebrata; Leg 181; Leg 90; Lower Pleistocene; Magnetic properties; Magnetic susceptibility; Marine sediments; Microfossils; Middle Pleistocene; New Zealand; ODP Site 1119; ODP Site 1125; Ocean Drilling Program; Organic compounds; Pacific Ocean; Paleo-oceanography; Paleoclimatology; Paleoecology; Paleoenvironment; Paleomagnetism; Paleotemperature; Pleistocene; Protista; Quaternary; Reflectance; Sediments; South Pacific; Southwest Pacific; Species diversity; Statistical analysis; Total organic carbon; West Pacific
Coordinates: S453129 S453128 E1745653 E1745652
S444520 S444520 E1722336 E1722336
S423259 S423259 W1780959 W1780959
Record ID: 2006031596
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