Tropical sea temperatures in the high-latitude South Pacific during the Eocene

Hollis, Christopher J.; Handley, Luke; Crouch, Erica M.; Morgans, Hugh E. G.; Baker, Joel A.; Creech, John; Collins, Katie S.; Gibbs, Samantha J.; Huber, Matthew; Schouten, Stefan; Zachos, James C; Pancost, Richard D.

doi:10.1130/g25200a.1

Cited by 187 publications

(275 citation statements)

References 32 publications

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“…Although oceans surrounding Early Cenozoic penguin localities were tropical/subtropical at the surface [19], subsurface temperatures were still significantly cooler than penguin body temperature of about 388C [7]. More importantly, longer feeding excursions far from the shoreline present greater thermoregulatory challenges, requiring a heterothermic solution.…”

Section: Discussionmentioning

confidence: 99%

“…49 Ma) [18]. Geochemical signals (oxygen isotopes, Mg/Ca ratios, alkenones) [19,20] suggest that Early Eocene sea-surface habitats were warmer than 258C at both the equator (proto-Peru) and 558 S (Zealandia or proto-New Zealand), and approximately 158C at 638 S (proto-Seymour Island) during the Early Eocene. The humeral plexus evolved during a time of marked warmth, indicating that its evolution was unrelated to the expansion of polar ice sheets and invasion of glacial environments by penguins.…”

Section: Discussionmentioning

confidence: 99%

“…The lack of significant Early Cenozoic cooling events [19] rules out a cool-climate driver for the evolution of the CCHE. Rather, the CCHE appears to have evolved in concert with dramatic skeletal modifications in Early Palaeogene stem penguins-changes that promoted neutral buoyancy and drag reduction, and thus improved long-distance swimming and deep-diving.…”

Section: Discussionmentioning

confidence: 99%

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Penguin heat-retention structures evolved in a greenhouse Earth

2010

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Penguins (Sphenisciformes) inhabit some of the most extreme environments on Earth. The 60+ Myr fossil record of penguins spans an interval that witnessed dramatic shifts in Cenozoic ocean temperatures and currents, indicating a long interplay between penguin evolution and environmental change. Perhaps the most celebrated example is the successful Late Cenozoic invasion of glacial environments by crown clade penguins. A major adaptation that allows penguins to forage in cold water is the humeral arterial plexus, a vascular counter-current heat exchanger (CCHE) that limits heat loss through the flipper. Fossil evidence reveals that the humeral plexus arose at least 49 Ma during a ‘Greenhouse Earth’ interval. The evolution of the CCHE is therefore unrelated to global cooling or development of polar ice sheets, but probably represents an adaptation to foraging in subsurface waters at temperate latitudes. As global climate cooled, the CCHE was key to invasion of thermally more demanding environments associated with Antarctic ice sheets.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Penguin heat-retention structures evolved in a greenhouse Earth

2010

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“…Both marine (Bijl et al, 2009;Hollis et al, 2009) and terrestrial (Carpenter et al, 2012;Contreras et al, 2014;Macphail et al, 1994) temperature proxy records suggest that the midlatitude to high-latitude southwest Pacific was extremely warm (25-35 • C) during the warmest intervals of the late Paleocene, Paleocene-Eocene Thermal Maximum (PETM; 56 Ma) and early Eocene, yielding a substantial mismatch between proxy data and climate-model output for this region that is yet unresolved (Hollis et al, 2012). The anomalously high temperatures may have partly resulted from large-scale tectonic changes such as the opening of the Tasmanian Gateway, and it has been hypothesized that this gateway played an important role in diverting ocean currents and influencing climate on a regional scale (Bijl et al, 2013a;Sijp et al, 2016Sijp et al, , 2014Sijp et al, , 2011 and beyond (e.g., Kennett, 1977).…”

Section: General Introductionmentioning

confidence: 99%

Identification of the Paleocene–Eocene boundary in coastal strata in the Otway Basin, Victoria, Australia

Frieling

Huurdeman

Rem

et al. 2018

J. Micropalaeontol.

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Abstract. Detailed, stratigraphically well-constrained environmental reconstructions are available for Paleocene and Eocene strata at a range of sites in the southwest Pacific Ocean (New Zealand and East Tasman Plateau; ETP) and Integrated Ocean Discovery Program (IODP) Site U1356 in the south of the Australo-Antarctic Gulf (AAG). These reconstructions have revealed a large discrepancy between temperature proxy data and climate models in this region, suggesting a crucial error in model, proxy data or both. To resolve the origin of this discrepancy, detailed reconstructions are needed from both sides of the Tasmanian Gateway. Paleocene-Eocene sedimentary archives from the west of the Tasmanian Gateway have unfortunately remained scarce (only IODP Site U1356), and no well-dated successions are available for the northern sector of the AAG. Here we present new stratigraphic data for upper Paleocene and lower Eocene strata from the Otway Basin, southeast Australia, on the (north)west side of the Tasmanian Gateway. We analyzed sediments recovered from exploration drilling (Latrobe-1 drill core) and outcrop sampling (Point Margaret) and performed high-resolution carbon isotope geochemistry of bulk organic matter and dinoflagellate cyst (dinocyst) and pollen biostratigraphy on sediments from the regional lithostratigraphic units, including the Pebble Point Formation, Pember Mudstone and Dilwyn Formation. Pollen and dinocyst assemblages are assigned to previously established Australian pollen and dinocyst zonations and tied to available zonations for the SW Pacific. Based on our dinocyst stratigraphy and previously published planktic foraminifer biostratigraphy, the Pebble Point Formation at Point Margaret is dated to the latest Paleocene. The globally synchronous negative carbon isotope excursion that marks the Paleocene-Eocene boundary is identified within the top part of the Pember Mudstone in the Latrobe-1 borehole and at Point Margaret. However, the high abundances of the dinocyst Apectodinium prior to this negative carbon isotope excursion prohibit a direct correlation of this regional bio-event with the quasi-global Apectodinium acme at the PaleoceneEocene Thermal Maximum (PETM; 56 Ma). Therefore, the first occurrence of the pollen species Spinizonocolpites prominatus and the dinocyst species Florentinia reichartii are here designated as regional markers for the PETM. In the Latrobe-1 drill core, dinocyst biostratigraphy further indicates that the early Eocene (∼ 56-51 Ma) sediments are truncated by a ∼ 10 Myr long hiatus overlain by middle Eocene (∼ 40 Ma) strata. These sedimentary archives from southeast Australia may prove key in resolving the model-data discrepancy in this region, and the new stratigraphic data presented here allow for detailed comparisons between paleoclimate records on both sides of the Tasmanian Gateway.

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“…Paleoclimate research has focussed on several time periods. These include those climates prior to the Quaternary period, such as the Eocene (55-34 million years ago) where global mean surface air temperatures were more then 10 • C warmer than today (see Huber, 2008Hollis et al, 2009). Also, other paleoclimate studies have focussed primarily on the representation of climate during the Last Glacial Maximum (see for example Drost et al, 2007) and the Mid-Holocene (Hall and Valdes, 1997), which look at the climate response to extensive ice sheets and changes in the Earth's orbital parameters.…”

Section: Introductionmentioning

confidence: 99%

The Southern Hemisphere semiannual oscillation and circulation variability during the Mid-Holocene

Ackerley

Renwick

2010

Clim. Past

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Abstract. The Paleoclimate Modelling Intercomparison Project (PMIP) was undertaken to assess the climatic effects of the presence of large ice-sheets and changes in the Earth's orbital parameters in fully coupled Atmosphere-Ocean General Circulation Models (AOGCMs). Much of the previous literature has focussed on the tropics and the Northern Hemisphere during the last glacial maximum and Mid-Holocene whereas this study focuses only on the Southern Hemisphere. This study addresses the representation of the Semiannual Oscillation (SAO) in the PMIP2 models and how it may have changed during the Mid-Holocene. The output from the five models suggest a weakening of the (austral) autumn circumpolar trough (CPT) and (in all but one model) a strengthening of the spring CPT. The effects of changing the orbital parameters are to cause warming and drying during spring over New Zealand and a cooling and moistening during autumn. The amount of spring warming/drying and autumn cooling/moistening is variable between the models and depends on the climatological locations of surface pressure anomalies associated with changes in the SAO. This study also undertakes an Empirical Orthogonal Function (EOF) analysis of the leading modes of atmospheric variability during the control and Mid-Holocene phases for each model. Despite the seasonal changes, the overall month by month and interannual variability was simulated to have changed little from the Mid-Holocene to present.

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Tropical sea temperatures in the high-latitude South Pacific during the Eocene

Cited by 187 publications

References 32 publications

Penguin heat-retention structures evolved in a greenhouse Earth

Penguin heat-retention structures evolved in a greenhouse Earth

Identification of the Paleocene–Eocene boundary in coastal strata in the Otway Basin, Victoria, Australia

The Southern Hemisphere semiannual oscillation and circulation variability during the Mid-Holocene

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