Bijl Peter K p.k.bijl@uu.nl 0000-0002-1710-4012 Bendle James A J.Bendle@bham.ac.uk 0000-0002-6826-8658 Bohaty Steven M steve.bohaty@geow.uni-heidelberg.de Pross Jörg Joerg.Pross@geow.uni-heidelberg.de Schouten Stefan Stefan.Schouten@nioz.nl Tauxe Lisa Stickley Catherine E McKay Robert M robert.mckay@vuw.ac.nz 0000-0002-5602-6985 Röhl Ursula uroehl@marum.de https://www.marum.de/en/Dr._Ursula_Roehl.html 0000-0001-9469-7053 Olney M Sluijs Appy A.Sluijs@bio.uu.nl 0000-0003-2382-0215 Escutia Dotti Carlota cescutia@ugr.es 0000-0002-4932-8619 Brinkhuis Henk h.brinkhuis@bio.uu.nl 0000-0003-0253-6610 Expedition 318 Scientists 2013 Eocene cooling linked to early flow across the Tasmanian Gateway dataset publication series https://doi.org/10.1594/PANGAEA.816368 2013-07-04T14:14:28 Bijl Peter K p.k.bijl@uu.nl 0000-0002-1710-4012 Bendle James A J.Bendle@bham.ac.uk 0000-0002-6826-8658 Bohaty Steven M steve.bohaty@geow.uni-heidelberg.de Pross Jörg Joerg.Pross@geow.uni-heidelberg.de Schouten Stefan Stefan.Schouten@nioz.nl Tauxe Lisa Stickley Catherine E McKay Robert M robert.mckay@vuw.ac.nz 0000-0002-5602-6985 Röhl Ursula uroehl@marum.de https://www.marum.de/en/Dr._Ursula_Roehl.html 0000-0001-9469-7053 Olney M Sluijs Appy A.Sluijs@bio.uu.nl 0000-0003-2382-0215 Escutia Dotti Carlota cescutia@ugr.es 0000-0002-4932-8619 Brinkhuis Henk h.brinkhuis@bio.uu.nl 0000-0003-0253-6610 Expedition 318 Scientists 2013 Eocene cooling linked to early flow across the Tasmanian Gateway journal article Proceedings of the National Academy of Sciences of the United States of America https://doi.org/10.1073/pnas.1220872110 The warmest global temperatures of the past 85 million years occurred during a prolonged greenhouse episode known as the Early Eocene Climatic Optimum (52-50 Ma). The Early Eocene Climatic Optimum terminated with a long-term cooling trend that culminated in continental-scale glaciation of Antarctica from 34 Ma onward. Whereas early studies attributed the Eocene transition from greenhouse to icehouse climates to the tectonic opening of Southern Ocean gateways, more recent investigations invoked a dominant role of declining atmospheric greenhouse gas concentrations (e.g., CO2). However, the scarcity of field data has prevented empirical evaluation of these hypotheses. We present marine microfossil and organic geochemical records spanning the early-to-middle Eocene transition fromthe Wilkes LandMargin, East Antarctica. Dinoflagellate biogeography and sea surface temperature paleothermometry reveal that the earliest throughflow of a westbound Antarctic Counter Current began ca. 49-50 Ma through a southern opening of the Tasmanian Gateway. This early opening occurs in conjunction with the simultaneous onset of regional surface water and continental cooling (2-4 °C), evidenced by biomarker- and pollen-based paleothermometry. We interpret that the westbound flowing current flow across the Tasmanian Gateway resulted in cooling of Antarctic surface waters and coasts, which was conveyed to global intermediate waters through invigorated deep convection in southern high latitudes. Although atmospheric CO2 forcing alone would provide a more uniform middle Eocene cooling, the opening of the Tasmanian Gateway better explains Southern Ocean surface water and global deep ocean cooling in the apparent absence of (sub-) equatorial cooling. Zachos James C jzachos@ernerald.ucsc.edu 0000-0001-8439-1886 Dickens Gerald Roy DICKENSG@tcd.ie 0000-0003-2869-4860 Zeebe Richard E 0000-0003-0806-8387 2008 Age and δ¹⁸O analysis relating to Cenozoic greenhouse climatesXXX dataset https://doi.org/10.1594/PANGAEA.816367 127.59091 149.92826 -63.31023 -34.39093 141.42623 -49.57180666666668 1998-11-07T03:30:00 2000-04-26T09:30:00 not specified IODP Integrated Ocean Drilling Program / International Ocean Discovery Program https://www.iodp.org/ ODP Ocean Drilling Program https://www-odp.tamu.edu:443/ Ocean Drilling Program, Texas A&M University ODP http://www-odp.tamu.edu/ https://ror.org/01f5ytq51 6 CC-BY-3.0 Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/ Sample code/label | Sample label | DSDP/ODP/IODP sample designation | Dinoflagellate cyst, endemic | Dinofl cysts end | Calculated | Apectodinium spp. | Dinoflagellate cyst, endemic and bipolar | Dinofl cysts end+bip | 5 pnt MA | Apectodinium | High | Tetraether index of 86 carbon atoms | TEX86 | Low | Sea surface temperature | SST | Cyclization ratio of branched tetraethers | CBT | Methylation index of branched tetraethers | MBT | Temperature, air, annual mean | MAAT supplement citable method50 method5059 param103316 param128253 param45381 param49427 param54066 param54067 param790 param81975 param88542 param95000 pi32931 author10820 author10904 author20308 author20377 author22032 author22741 author23310 author25020 author26503 author28361 author32928 author32931 author43907 author45547 author46082 author898 author900 geocode1599 geocode1600 geocode1601 inst34 journal13288 license101 project3 project4048 ref57182 refds816367 topotype1