Radiolarian-based paleotemperatures of ODP Site 177-1089 in the Atlantic Sector of the Southern Ocean

• Main Authors: Cortese, Giuseppe, Abelmann, Andrea
• Format: Other/Unknown Material
• Language: English
• Published: PANGAEA 2002
• Subjects: 177-1089; Agulhas Basin; Agulhas Ridge; ANT-IV/3; ANT-IV/4; ANT-IX/2; ANT-IX/4; ANT-VIII/3; ANT-VIII/6; ANT-X/5; ANT-XI/2; ANT-XI/4; Astrid Ridge; Atka Bay; Atlantic Ridge; AWI_Paleo; Brazil Basin; Cape Basin; COMPCORE; Composite Core; Filchner Shelf; Fram Strait; GeoB2004-1; GeoB2007-1; GeoB2008-1; GeoB2016-3; GeoB2018-1; GeoB2019-2; GeoB2021-4; GeoB2022-3; Giant box corer; GKG; Gravity corer (Kiel type); Indian-Antarctic Ridge; Joides Resolution; Lazarev Sea; Leg177; M23/1; Maud Rise; Meteor (1986); Meteor Rise; MIC; MiniCorer; MSN; MUC; MultiCorer; Multiple opening/closing net; Ocean Drilling Program; ODP; Paleoenvironmental Reconstructions from Marine Sediments @ AWI; Antarc*; Antarctic; GISP; Greenland; GRIP; Southern Ocean
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.706557; https://doi.org/10.1594/PANGAEA.706557

Two cores, Site 1089 (ODP Leg 177) and PS2821-1, recovered from the same location (40°56'S; 9°54'E) at the Subtropical Front (STF) in the Atlantic Sector of the Southern Ocean, provide a high-resolution climatic record, with an average temporal resolution of less than 600 yr. A multi-proxy approach was used to produce an age model for Core PS2821-1, and to correlate the two cores. Both cores document the last climatic cycle, from Marine Isotopic Stage 6 (MIS 6, ca. 160 kyr BP, ka) to present. Summer sea-surface temperatures (SSSTs) have been estimated, with a standard error of ca. +/-1.16°C, for the down core record by using Q-mode factor analysis (Imbrie and Kipp method). The paleotemperatures show a 7°C warming at Termination II (last interglacial, transition from MIS 6 to MIS 5). This transition from glacial to interglacial paleotemperatures (with maximum temperatures ca. 3°C warmer than present at the core location) occurs earlier than the corresponding shift in delta18O values for benthic foraminifera from the same core; this suggests a lead of Southern Ocean paleotemperature changes compared to the global ice-volume changes, as indicated by the benthic isotopic record. The climatic evolution of the record continues with a progressive temperature deterioration towards MIS 2. High-frequency, millennial-scale climatic instability has been documented for MIS 3 and part of MIS 4, with sudden temperature variations of almost the same magnitude as those observed at the transitions between glacial and interglacial times. These changes occur during the same time interval as the Dansgaard-Oeschger cycles recognized in the delta18Oice record of the GRIP and GISP ice cores from Greenland, and seem to be connected to rapid changes in the STF position in relation to the core location. Sudden cooling episodes ('Younger Dryas (YD)-type' and 'Antarctic Cold Reversal (ACR)-type' of events) have been recognized for both Termination I (ACR-I and YD-I events) and II (ACR-II and YD-II events), and imply that our core is located ...