Transient temperature asymmetry between hemispheres in the Palaeogene Atlantic Ocean

Liu, Zhonghui; He, Yuxin; Jiang, Yiqing; Wang, Huanye; Liu, Weiguo; Bohaty, Steven M; Wilson, Paul A.

doi:10.1038/s41561-018-0182-9

Cited by 54 publications

(92 citation statements)

References 54 publications

(80 reference statements)

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“…The new SST record generated here for Site 1406A confirms that very warm waters, typical of today's tropical latitudes, extended through midlatitudes in the western North Atlantic during the Oligocene to early Miocene, as suggested by previous biomarker studies (Liu et al, ; Super et al, ) as well as evidenced by Northern Hemisphere fossil flora records (Kotthoff et al, ; Larsson et al, ). Furthermore, our new data from both TEX 86 and

U_{37}^{k'}

at the same site confirm similar temperature estimates.…”

Section: Discussionsupporting

confidence: 84%

“…During some time intervals, the 1406A temperature estimates differ in absolute values and trends from those of the proximal but deeper Site 1404 (Liu et al, ; modern location: 40.00°N, 51.60°W; 4, 710 m bsl; Figure ). Temperatures are compared here for both records using the BAYSPLINE calibration (Tierney & Tingley, ).…”

Section: Discussionmentioning

confidence: 92%

“…The paleolatitude of Exp. 342 sites does not differ significantly from their modern latitude due to the polar location of the rotation pole of the mid‐Atlantic ridge, which led to a longitudinal rather than poleward, tectonic migration of the Newfoundland banks, attaining a position of 41°N, 46°W by 18 Ma (Liu et al, ).…”

Section: Methodsmentioning

confidence: 99%

“…In contrast to the late Miocene, where over a dozen globally distributed temperature records from alkenone unsaturation ratios (

U_{37}^{k'} true)

record pronounced midlatitude and high‐latitude cooling (Herbert et al, ), absolute sea surface temperature (SST) estimates for the Oligocene to early Miocene are very limited in time and spatial extent. One late Eocene through Oligocene temperature record from

U_{37}^{k'}

in north Atlantic sediments suggests temperatures averaging 26 °C (Liu et al, ). The TEX 86 temperature proxy based upon glycerol dialkyl glycerol tetraethers (GDGTs) was used to reconstruct temperatures for the last 40 Myr in the tropical and high‐latitude North Atlantic Ocean (Super et al, ; Zhang et al, ).…”

Section: Introductionmentioning

confidence: 99%

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Midlatitude Temperature Variations in the Oligocene to Early Miocene

Guitián

Phelps

Polissar

et al. 2019

Paleoceanog and Paleoclimatol

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Antarctic ice sheet margin extent and the sensitivity of benthic δ18O to orbital forcing have varied on million‐year timescales during the Oligocene to Early Miocene. However, few sea surface temperature (SST) records for this time interval exist to evaluate links between polar processes and mean temperature outside polar regions. Here, we present a new record of SST for the time interval 30 to 17 Ma derived from the long‐chain alkenone unsaturation ratio ( U37k′) at Integrated Ocean Drilling Program Site 1406A in the midlatitude North Atlantic. Results confirm that warm temperatures from 24°C to over 30°C prevailed in midlatitudes in this time and suggest a transition from colder early‐middle Oligocene to warmer average conditions after 24.5 Ma. The global significance of this transition is highlighted by the coincidence with changes in the dominance from marine‐ to terrestrial‐terminating ice sheets in the Ross Sea around Antarctica. The longest continuous section of the record (20.6 to 26.6 Ma) contains multiple 2 million‐year cycles in SST, potentially paced by long obliquity modulation. Complex and temporally varying relationships are observed between North Atlantic SST and benthic δ18O in paired samples; significant covariation is only observed around the Oligocene‐Miocene transition, coincident with a lower average marine ice extent. These North Atlantic U37k′ temperature records provide a new context in which to examine the stability of climate and the Antarctic ice sheet during the Oligocene and early Miocene.

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U_{37}^{k'}

at the same site confirm similar temperature estimates.…”

Section: Discussionsupporting

confidence: 84%

Section: Discussionmentioning

confidence: 92%

Section: Methodsmentioning

confidence: 99%

“…In contrast to the late Miocene, where over a dozen globally distributed temperature records from alkenone unsaturation ratios (

U_{37}^{k'} true)

U_{37}^{k'}

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Midlatitude Temperature Variations in the Oligocene to Early Miocene

Guitián

Phelps

Polissar

et al. 2019

Paleoceanog and Paleoclimatol

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“…Tectonic reconstruction of Antarctica and its surrounding continents at 34 Ma (obtained from the Ocean Drilling Stratigraphic Network, after Hay et al, ) also showing study sites for published stable isotope and Mg/Ca records that span Step 1 of the EOT (blue open circles; see text for details) (Bohaty et al, ; Katz et al, ; Lear et al, ; Peck et al, ; Wade et al, ). Also shown are sites where latest Eocene alkenone‐based sea surface temperature records have been collected (red open circles; see text for details) (Liu et al, ; Liu et al, ; Plancq et al, ). Inset: study site location in South Australia in present geographic coordinates.…”

Section: Introductionmentioning

confidence: 99%

Midlatitude Southern Hemisphere Temperature Change at the End of the Eocene Greenhouse Shortly Before Dawn of the Oligocene Icehouse

Haiblen

Opdyke

Roberts

et al. 2019

Paleoceanog and Paleoclimatol

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The Eocene-Oligocene transition (EOT) marked the initiation of large-scale Antarctic glaciation. This fundamental change in Cenozoic climate state is recorded in deep-sea sediments by a rapid benthic foraminiferal δ 18 O increase and appearance of ice-rafted debris in the Southern Ocean. However, we know little about the magnitude of cooling associated with the EOT in shallow water environments, particularly at middle to high latitudes. Here we present new stratigraphic records of the C13r/C13n magnetochron boundary and the EOT in the clay-rich Blanche Point Formation, South Australia. The Blanche Point Formation was deposited in a shallow shelf setting (water depths of <100 m) at a paleolatitude of~51°S. We present high-resolution δ 18 O, δ 13 C, and Mg/Ca records of environmental change from well-preserved benthic foraminifera of latest Eocene age at this site. A marked, negative δ 13 C excursion occurs immediately before EOT Step 1 and may be a globally representative signal. An~2°C cooling of shallow shelf seawater is evident from benthic foraminiferal Mg/Ca across Step 1. This cooling signal is both sufficient to account fully for the δ 18 O increase in our data and is of similar amplitude to that documented in published records for shallow shelf and upper water column open ocean settings, which suggests no obvious polar amplification of this cooling signal. Our results strengthen the evidence base for attributing EOT Step 1 to global cooling with little contribution from ice volume growth and contradict the mechanism suggested to explain the inferred northward migration of the intertropical convergence zone in the contemporaneous equatorial Pacific Ocean. Key Points:• We present a detailed stable isotopic and Mg/Ca record for the early Eocene-Oligocene transition from southern Australia at~51°S • Shallow shelf (<100 m deep) seawater temperatures fell 2°C across this part of the transition • Surface seawater δ18O values were probably closer to positive one than negative one within this embayment in the latest Eocene, indicating that a source of relatively saline water was present at this time Supporting Information:• Supporting Information S1

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Leaf‐economic strategies across the Eocene–Oligocene transition correlate with dry season precipitation and paleoelevation

Butrim

Royer

2020

American J of Botany

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PREMISE The Eocene–Oligocene transition (EOT; 34–33 Ma) was marked by global cooling and increased seasonality and aridity, leading to a shift in North American floras from subtropical forests to deciduous hardwood forests similar to today. This shift is well documented taxonomically and biogeographically, but its ecological nature is less known. METHODS Using the relationship between petiole cross‐sectional area and leaf mass, we estimated leaf dry mass per area (LMA), a functional trait tied to plant resource investment and expenditure, at 22 western North American sites spanning the EOT to determine how the broad restructuring of vegetation during this time was reflected in leaf economics. RESULTS There was no overall shift in LMA between pre‐EOT and post‐EOT floras; instead, changes in LMA across sites were mostly driven by a negative correlation with dry‐season precipitation and a positive correlation with paleoelevation. These patterns held for both whole sites and subsets of sites containing taxa with similar biogeographical histories (taxa that persisted in the highlands across the EOT or that migrated to the lowlands) and are consistent with most observations in extant floras. CONCLUSIONS Our data provide a geological context for understanding environmentally paced changes in leaf‐economic strategies, particularly linking leaf economic strategies to dry‐season precipitation and paleoelevation.

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Transient temperature asymmetry between hemispheres in the Palaeogene Atlantic Ocean

Cited by 54 publications

References 54 publications

Midlatitude Temperature Variations in the Oligocene to Early Miocene

Midlatitude Temperature Variations in the Oligocene to Early Miocene

Midlatitude Southern Hemisphere Temperature Change at the End of the Eocene Greenhouse Shortly Before Dawn of the Oligocene Icehouse

Leaf‐economic strategies across the Eocene–Oligocene transition correlate with dry season precipitation and paleoelevation

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