Publication Date:
2023-07-10
Description:
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. Coolest glacials are marked by a strong inflow of cool, southern-sourced waters at Site Y8 indicating a more vigorous flow along the Subantarctic Front (SAF).
Keywords:
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; Cannobotryidae; Carpocanarium papillosum group; Carpocaniidae; Carpocanistrum acutidentatum; Carpocanistrum spp.; Carposphaera sp. cf. C. capillacea; Cenosphaera cristata; Cenosphaera sp. aff. C. perforata; Cenosphaera spp.; Ceratocyrtis galeus; Ceratocyrtis histricosus; Ceratocyrtis spp.; Circodiscus microporus; Cladoscenium ancoratum; Cladoscenium sp. cf. C. tricolpium; Clathrocanium coarctatum; Clathrocorys murrayi; Coccodiscidae; Collosphaera confossa; Collosphaera huxleyi; Collosphaera macropora; Collosphaera spp.; Collosphaeridae; Cornutella bimarginata; Cornutella profunda; Corocalyptra alcmenae; Corocalyptra cervus/gegenbauri; Corocalyptra columba; Counting 〉45 µm fraction; Cromyechinus antarctica; Cubotholus spp.; Cycladophora bicornis; Cycladophora davisiana; Cyrtopera laguncula; Depth, bottom/max; DEPTH, sediment/rock; Depth, top/min; Dictyocoryne profunda; Dictyophimus bicornis; Dictyophimus hirundo; Dictyophimus infabricatus; Dictyophimus platicephalus; Dictyophimus spp.; Didymocyrtis sp. cf. D. tetrathalamus; Didymocyrtis tetrathalamus; Dipylissa bensoni; Disolenia zanguebarica; Druppatractus hastatus; Druppatractus irregularis; Druppatractus spp.; Druppatractus variabilis; Euchitonia elegans/furcata group; Eucyrthidium acuminatum octocolum; Eucyrtidium acuminatum acuminatum; Eucyrtidium annulatum; Eucyrtidium anomalum; Eucyrtidium hexagonatum; Eucyrtidium hexastichum; Eucyrtidium matuyamai; Eucyrtidium spp.; Eucyrtidium teuscheri; Euphysetta elegans; GeoB; Geosciences, University of Bremen; Gondwanaria dogieli; Haliometta miocenica; Heliodiscus asteriscus; Hexacontium aristarchi; Hexacontium armatum/hostile group; Hexacontium laevigatum; Hexacontium spp.; Hexastylus spp.; Hexastylus triaxonius; KAL; Kasten corer; Lamprocyclas maritalis maritalis; Lamprocyclas maritalis polypora; Lamprocyrtis nigriniae; Lampromitra cracenta; Lampromitra quadricuspis; Lampromitra schultzei; Lampromitra spp.; Larcopyle buetschlii; Larcopyle spp.; Larcospira quadrangula; Lipmanella bombus; Lipmanella dictyoceras; Lirellidae; Litharachnium tentorium; Litheliidae; Lithelius minor group; Lithelius nautiloides; Lithelius spp.; Lithocampe furcaspiculata; Lithocampe platycephala; Lithocarpium sp.; Lithomelissa borealis; Lithomelissa hystrix; Lithomelissa laticeps; Lithomelissa sp.; Lithomelissa spp.; Lithomelissa stigi; Lithomelissa thoracites; Lithostrobus hexagonalis; Lophophaena buetschlii; Lophophaena hispida; Lophophaena spp.; Lophospyris juvenile; Lophospyris pentagona pentagona; Lophospyris spp.; Mitrocalpis araneafera; Nassellaria; Neosemantis distephanus; Octopyle stenozona; offshore eastern New Zealand; Ommatodiscus cf. haeckeli; Peridium longispinum; Peripyramis circumtexta; Peromelissa phalacra; Phacodiscidae; Phaeodaria; Phormacantha hystrix; Phormospyris spp.; Phormospyris stabilis scaphipes; Phormospyris stabilis stabilis; Phormostichoartus corbula; Phorticium clevei; Phorticium pylonium group; Plagoniidae; Plagoniidae group; Plectacantha sp.; Plectopyramis dodecomma; Porodiscus sp.; Prunopyle spp.; Prunopyle titan; Pseudocubus obeliscus; Pseudodictyophimus gracilipes; Pterocanium praetextum group; Pterocanium sp.; Pterocanium spp.; Pterocanium trilobum; Pterocoryidae; Pterocorys clausus; Pterocorys macroceras; Pterocorys minythorax; Pterocorys sp.; Pterocorys spp.; Pterocorys zancleus; Pylolena armata; Pylonidae; Pylospira octopyle; Rhizoplegma boreale; Saccospyris antarctica; Sample code/label; Saturnalis circularis; Schizodiscus spatangus; Sethoconus tabulatus; Sethodiscus macrococcus; Sethophormis rotula; Siphocampe arachnea group; Siphocampe lineata group; Siphocampe nodosaria; Siphonosphaera martensi; Siphonosphaera socialis; Spirocyrtis scalaris group; Spirocyrtis subscalaris; Spongocore puella; Spongodiscidae; Spongodiscus resurgens; Spongopyle osculosa; Spongotrochus glacialis; Spongotrochus venustum; Spongurus pylomaticus; Spongurus sp.; Spumellaria; Stichopilium variabile var. davisianoides; Streblacantha circumtexta; Stylatractus spp. group; Stylochlamidium asteriscus; Stylochlamidium spp.; Stylodictya aculeata; Stylodictya validispina; Stylosphaera melpomene; Styptosphaera spumacea; T3034_Y8; TAN3034; Tangaroa; Tetrapyle octacantha; Thecosphaera inermis; Thecosphaera spp.; Theocorys veneris; Theocorythium trachelium dianae; Theocorythium trachelium trachelium; Theoperidae; Theopilium tricostatum; Tholonidae; Tholospyris rhombus; Triceraspyris antarctica; Triceraspyris sp. cf. T. antarctica; Trissocyclidae; Trisulcus spp.; Trisulcus triacanthus; Zygocircus productus group
Type:
Dataset
Format:
text/tab-separated-values, 16767 data points
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