Early<scp>M</scp>iocene<scp>M</scp>ollusca from<scp>M</scp>c<scp>M</scp>urdo<scp>S</scp>ound,<scp>A</scp>ntarctica (<scp>ANDRILL</scp>2<scp>A</scp>drill core), with a review of<scp>A</scp>ntarctic<scp>O</scp>ligocene and<scp>N</scp>eogene<scp>P</scp>ectinidae (<scp>B</scp>ivalvia)

Beu, Alan G.; Taviani, Marco

doi:10.1111/pala.12067

Cited by 22 publications

(21 citation statements)

References 106 publications

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“…The interval between 428.28 and 436.18 mbsf incorporates a single sequence comprising a basal diamictite overlain by a sandstone unit with relatively abundant marine bivalves. Thick-shelled costate scallops and venerid clams recovered from this interval indicate that water temperatures were at least 5°C warmer than in the Ross Sea today (29). Relatively warm water temperatures are supported by TEX 86 L and Δ 47 data, which indicate SWT at the coastal margin reached a maximum between 7.0 ± 2.8°C and 10.4 ± 2.5°C.…”

Section: Resultsmentioning

confidence: 73%

Antarctic ice sheet sensitivity to atmospheric CO ₂ variations in the early to mid-Miocene

Levy

Harwood

Florindo

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

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172

273

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Geological records from the Antarctic margin offer direct evidence of environmental variability at high southern latitudes and provide insight regarding ice sheet sensitivity to past climate change. The early to mid-Miocene (23–14 Mya) is a compelling interval to study as global temperatures and atmospheric CO2 concentrations were similar to those projected for coming centuries. Importantly, this time interval includes the Miocene Climatic Optimum, a period of global warmth during which average surface temperatures were 3–4 °C higher than today. Miocene sediments in the ANDRILL-2A drill core from the Western Ross Sea, Antarctica, indicate that the Antarctic ice sheet (AIS) was highly variable through this key time interval. A multiproxy dataset derived from the core identifies four distinct environmental motifs based on changes in sedimentary facies, fossil assemblages, geochemistry, and paleotemperature. Four major disconformities in the drill core coincide with regional seismic discontinuities and reflect transient expansion of grounded ice across the Ross Sea. They correlate with major positive shifts in benthic oxygen isotope records and generally coincide with intervals when atmospheric CO2 concentrations were at or below preindustrial levels (∼280 ppm). Five intervals reflect ice sheet minima and air temperatures warm enough for substantial ice mass loss during episodes of high (∼500 ppm) atmospheric CO2. These new drill core data and associated ice sheet modeling experiments indicate that polar climate and the AIS were highly sensitive to relatively small changes in atmospheric CO2 during the early to mid-Miocene.

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Section: Resultsmentioning

confidence: 73%

Antarctic ice sheet sensitivity to atmospheric CO ₂ variations in the early to mid-Miocene

Levy

Harwood

Florindo

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

Self Cite

172

273

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“…They interpreted the presence of Hiatella cf. arctica as indicative of relatively warm sea temperatures (~5°C warmer than present Ross Sea temperatures; Beu and Taviani, 2014). Most notably, fragments of multiple Pectinid species and a complete Hiatella cf.…”

Section: Comparison With Other Evidence From And-2amentioning

confidence: 99%

“…We also compared palynological data with mollusk data from Beu and Taviani (2014), who found mollusks, including diverse Pectinidae, in several AND-2A intervals. They interpreted the presence of Hiatella cf.…”

Section: Comparison With Other Evidence From And-2amentioning

confidence: 99%

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Early to middle Miocene vegetation history of Antarctica supports eccentricity-paced warming intervals during the Antarctic icehouse phase

Griener

Warny

Askin

2015

Global and Planetary Change

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“…To the degree that temperature is responsible for the differences in size and color, these observations together further suggest that the early Permian high southern latitudes were not as cold as those today. Indeed the Miocene again presents a reasonable analog, as some Miocene Antarctic bivalves are strikingly similar to common Permian ones [e.g., Miocene Australochlamys anderssoni (Beu and Taviani, 2014, Fig. 3D) and Permian Deltopecten mitchelli (Waterhouse, 1987, Plate 4, Fig.…”

Section: Perspectives On High-latitude Settingsmentioning

confidence: 96%

Gradients in seasonality and seawater oxygen isotopic composition along the early Permian Gondwanan coast, SE Australia

Beard

Ivany

Runnegar

2015

Earth and Planetary Science Letters

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Oxygen isotope compositions of marine carbonates are commonly employed for understanding ancient temperatures, but this approach is complicated in the very distant past due to uncertainties about the effects of diagenesis and the isotopic composition of seawater, both locally and globally. Microsampled accretionary calcite from two species of the fossil bivalve Eurydesma Sowerby and Morris 1845 collected from sediments of Cisuralian age in high latitude marine sediments along the SE coast of Australia records cyclic seasonal fluctuations in shell δ 18 O values during growth, demonstrating the primary nature of the isotope signal and thus allowing investigation of early Permian seawater isotopic composition and water temperature in the high southern latitudes. The mean and seasonal range of δ 18 O carb decreases poleward across about 10 • of paleolatitude (∼67 • S-77 • S). The presence of co-occurring dropstones and stratigraphically associated glendonites constrains winter temperatures across the region to near-freezing, thus permitting calculation of realistic estimates of water composition and summer temperatures.Summer δ 18 O carb values indicate water temperatures between 5 • C and 12 • C, with warmer values at lower latitudes. The decrease in both mean sea surface temperature and seasonal amplitude with increasing latitude on the Gondwanan coast is much like that observed along high-latitude coastlines today. Calculated δ 18 O water decreases toward the pole, likely associated with an increasing contribution of isotopically light fresh water derived from summer snow-melt. The gradient in δ 18 O water is similar to that documented over a similar span of latitude on the modern SE Greenland coast. We infer the presence of a north-flowing coastal current of cold, O 18 -depleted water that entrains progressively greater amounts of more typical seawater as it moves away from the pole. δ 18 O values in SE Australia, however, are about 3h lower than those off Greenland, suggesting comparatively lower salinity water or more O 18 -depleted glacial ice/runoff in the Permian Gondwanan high latitudes, perhaps augmented by more depleted (negative) global average seawater. Conditions in southeastern Australia during the largest of the Permian deglaciations were warmer than present-day Antarctica at similar latitudes, but may approximate those of early-mid Miocene Antarctica, with frozen winters but summers closer to 10 • C.

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EarlyMioceneMollusca fromMcMurdoSound,Antarctica (ANDRILL2Adrill core), with a review ofAntarcticOligocene andNeogenePectinidae (Bivalvia)

Cited by 22 publications

References 106 publications

Antarctic ice sheet sensitivity to atmospheric CO ₂ variations in the early to mid-Miocene

Antarctic ice sheet sensitivity to atmospheric CO ₂ variations in the early to mid-Miocene

Early to middle Miocene vegetation history of Antarctica supports eccentricity-paced warming intervals during the Antarctic icehouse phase

Gradients in seasonality and seawater oxygen isotopic composition along the early Permian Gondwanan coast, SE Australia

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EarlyMioceneMollusca fromMcMurdoSound,Antarctica (ANDRILL2Adrill core), with a review ofAntarcticOligocene andNeogenePectinidae (Bivalvia)

Cited by 22 publications

References 106 publications

Antarctic ice sheet sensitivity to atmospheric CO 2 variations in the early to mid-Miocene

Antarctic ice sheet sensitivity to atmospheric CO 2 variations in the early to mid-Miocene

Early to middle Miocene vegetation history of Antarctica supports eccentricity-paced warming intervals during the Antarctic icehouse phase

Gradients in seasonality and seawater oxygen isotopic composition along the early Permian Gondwanan coast, SE Australia

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Antarctic ice sheet sensitivity to atmospheric CO ₂ variations in the early to mid-Miocene

Antarctic ice sheet sensitivity to atmospheric CO ₂ variations in the early to mid-Miocene