Late Miocene paleoclimatology; subantarctic water mass, Southwest Pacific

Author(s): Loutit, Tom S.
Author Affiliation(s): Primary:
Univ. R.I., Grad. Sch. Oceanogr., Kingston, RI, United States
Volume Title: Marine Micropaleontology
Source: Marine Micropaleontology, 6(1), p.1-27. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0377-8398 CODEN: MAMIDH
Note: In English. 3 p. refs.; illus. incl. 4 tables, 2 plates, sketch map
Summary: The Late Miocene--Early Pliocene paleoclimatic history has been evaluated for a deep drilled sediment sequence at Deep Sea Drilling Project Site 281 and a shallow water marine sediment sequence at Blind river, New Zealand, both of which lay within the Subantarctic water mass during the Late Miocene. A major, faunally determined, cooling event within the latest Miocene at Site 281 and Blind River coincides with oxygen isotopic changes in benthonic foraminiferal composition at DSDP Site 284 considered to indicate a significant increase in Antarctic ice sheet volume. However, at Site 281 benthonic foraminiferal oxygen isotopic changes do not record such a large increase in Antarctic ice volume. It is possible that the critical interval is within an unsampled section (no recovery) in the latest Miocene. Paleoclimatic histories from the two sections are very similar. Surface water temperatures and Antarctic ice-cap volume appear to have been relatively stable during the late Middle--early Late Miocene (early--late Tongaporutuan). By 6.4 m.y. cooler conditions prevailed at Site 281. Between 6.3 and 6.2 m.y. the carbon isotopic shift occurred followed, within 100,000 yr, by a distinct shallowing of water depths at Blind River. The earliest Pliocene (Opoitian) is marked by increasing surface-water temperatures. (Auth. mod.)
Year of Publication: 1981
Research Program: DSDP Deep Sea Drilling Project
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Antarctic Ocean; Australasia; Benthic taxa; Biostratigraphy; Blind River; C-13/C-12; Carbon; Cenozoic; DSDP Site 281; DSDP Site 284; Deep Sea Drilling Project; Foraminifera; Invertebrata; Isotopes; Leg 29; Microfossils; Mid-Antarctic Ridge; Miocene; Neogene; New Zealand; O-18/O-16; Oxygen; Pacific Ocean; Paleocirculation; Paleoclimatology; Paleocurrents; Paleotemperature; Planktonic taxa; Protista; South Island; South Pacific; Southwest Pacific; Stable isotopes; Stratigraphy; Tasman Sea; Tertiary; Upper Miocene; West Pacific
Coordinates: S480000 S480000 E1474600 E1474600
Record ID: 1982045499
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from the Antarctic Bibliography, United States, Reference includes data from PASCAL, Institute de l'Information Scientifique et Technique, Vandoeuvre-les-Nancy, France