Radiolarian abundance of sediment core Y8

• Main Authors: Lüer, Vanessa, Cortese, Giuseppe, Neil, Helen L, Hollis, Christopher J, Willems, Helmut
• Format: Dataset
• Language: English
• Published: PANGAEA 2009
• Subjects: Acanthosphaera actinota; Acanthosphaera dodecastyla; Acanthosphaera pinchuda; Acanthosphaera spp.; Acrosphaera arktios; Acrosphaera cyrtodon; Acrosphaera inflata; Acrosphaera lappacea; Acrosphaera mercurius; Acrosphaera murrayana; Acrosphaera spinosa; Acrosphaera spp.; Actinomma antarcticum; Actinomma arcadophorum; Actinomma delicatulum; Actinomma leptodermum leptodermum; Actinomma leptodermum longispina; Actinomma medianum; Actinomma sol; Actinomma spp.; Actinomma trinacria; Actinommidae; Actinosphaera acanthophora; AGE; Amphiplecta acrostoma; Amphirhopalum ypsilon; Androcyclas gamphonycha; Anomalacantha dentata; Antarctissa cylindrica; Antarctissa denticulata; Antarctissa longa; Antarctissa sp. cf. denticulata; Antarctissa spp.; Antarctissa strelkovi; Anthocyrtidium ophirense; Anthocyrtidium zanguebaricum; Arachnocorallium calvata; Arachnocorys umbellifera; Archipilium macroporus; Artostrobiidae; Artostrobus annulatus; Artostrobus joergenseni; Axoprunum bispiculum; Axoprunum stauraxonium; Bathropyramis woodringi; Botryocampe cf. inflata; Botryocampe conythorax; Botryopyle dictyocephalus; Botryostrobus aquilonaris; Botryostrobus auritus/australis; New Zealand; Campbell Plateau; Antarc*
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.691487; https://doi.org/10.1594/PANGAEA.691487

A high-resolution record of radiolarian faunal changes from Site Y8 south of the Subtropical Front (STF), offshore eastern New Zealand, provides insight into the paleoceanographic history of the last 265 kyrs. Quantitative analysis of radiolarian paleotemperature indicators and radiolarian-based sea surface temperature (SST) estimates reveal distinct shifts during glacial-interglacial (G-I) climate cycles encompassing marine isotope stages (MIS) 8-1. Faunas at Site Y8 are abundant and diverse and consist of a mixture of species typical of the subantarctic, transitional and subtropical zones which is characteristic of subantarctic waters just south of the STF. During interglacials, diverse radiolarian faunas have increased numbers of warm-water taxa (not, vert, similar 15%) while cool-water taxa decrease to not, vert, similar 11% of the assemblage. Warmest climate conditions occurred during MIS 5.5 and the early Holocene Climatic Optimum (HCO) at the onset of MIS 1 where SSTs reach maxima of 12.8 and 12.9 °C, respectively. This suggests that temperatures during the HCO were comparable to the Eemian, one of the warmest interglacial intervals of the Late Quaternary. Glacials are characterized by less diverse radiolarian faunas with cool-water taxa increasing to 49% of the assemblage. Coolest climate conditions occurred in MIS 4 and 2 where SSTs are reduced to 5.4 °C and 4.3 °C, respectively. Radiolarian faunal changes and SST estimates clearly identify major water masses and oceanic fronts in the offshore eastern New Zealand area. During warmest MIS 5.5 and early MIS 1 substantial influence of northern-sourced Subtropical Surface Water (STW) is evident at Site Y8. This implies southward incursions of STW around the eastern crest of Chatham Rise with the STF displaced towards higher latitudes and spinning off eddies as far south as Campbell Plateau. Additionally, increased flow of the Southland Current (SC) might have enhanced the local occurrence of warm-water radiolarians derived from the subtropical Tasman Sea. ...