Late Cretaceous winter sea ice in Antarctica?

Bowman, Vanessa C.; Francis, Jane E.; Riding, James B.

doi:10.1130/g34891.1

Cited by 78 publications

(69 citation statements)

References 33 publications

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“…This has confirmed the Maastrichtian-Danian age of the succession, and also the high rate of sedimentation during the Cretaceous-Paleogene interval (10-20 cm/kyr), with the entire sequence on SI likely deposited in b4 million years (Tobin et al, 2012;Bowman et al, 2013). The homogenous nature of these deposits, and the lack of significant grain size variation or evidence for significant hiatuses, suggests essentially continuous sedimentation.…”

Section: Stratigraphysupporting

confidence: 66%

“…The LBF on SI is composed of fairly monotonous sandy to clayey siltstones, with occasional well-cemented sandier layers, some of which contain post-depositional carbonate concretions. A number of discrete beds throughout the succession also contain significant amounts of glauconite (Macellari, 1988;Crame et al, 2004;Bowman et al, 2013). Primary depositional textures are often obscured by freeze-thaw weathering of the surface, and in places by apparently extensive bioturbation, and primary sedimentary fabrics have never been studied systematically (though see Olivero et al, 2007;Olivero et al, 2008).…”

Section: Stratigraphymentioning

confidence: 97%

“…Large-scale blooms of the dinoflagellate cyst Impletosphaeridium clavus in the LBF have been linked to the decay of ephemeral sea ice during short-lived 'cold snaps' (Bowman et al, 2013) correlated to isotopic evidence for cool ocean temperatures (Tobin et al, 2012;Petersen et al, 2016). Others have suggested that these blooms are related to periods of higher continental nutrient influx and eutrophication, without the need to invoke sea ice formation (Amenábar et al, 2014).…”

Section: Dynamics Of Anoxia In the Jrbmentioning

confidence: 97%

“…However, the subdivisions are differentiated in published geological maps (e.g., Montes et al, 2013), meaning that their boundaries, along with other features such as the K-Pg boundary and several distinctive glauconite-rich horizons, can be used to attempt correlation between sets of samples collected by different workers (e.g., Bowman et al, 2013;Witts et al, 2016, Section 2.4).…”

Section: Stratigraphymentioning

confidence: 98%

“…The samples analyzed in this study were collected from parallel sections across northern and southern Seymour Island, collected by two different research teams: a section collected by a joint Caltech and CADIC -Conicet-IAA team (hereafter the T12 section; first published in Tobin et al, 2012) and the British Antarctic Survey (BAS) composite section D5.251 (published in Bowman et al, 2013;Witts et al, 2016). While direct meter-to-meter correlation of sections collected from different parts of the island is not always possible due to the difficulties outlined above, especially in the lower portion of the sequence, correlations between sections can be established with reasonable confidence.…”

Section: Stratigraphic Correlationmentioning

confidence: 99%

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Intermittent euxinia in the high-latitude James Ross Basin during the latest Cretaceous and earliest Paleocene

Schoepfer

Tobin

Witts

et al. 2017

Palaeogeography, Palaeoclimatology, Palaeoecology

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Available online xxxx Seymour Island, in the James Ross Basin, Antarctica, contains a continuous succession of latest Cretaceous sediments deposited in a shallow marine environment at high latitude, making it an ideal place to study environmental changes prior to the K-Pg mass extinction. We measured major and trace elements and conducted petrographic analysis of two sections from the Maastrichtian-Danian López de Bertodano Formation of Seymour Island. Several lines of evidence point to intermittently anoxic to euxinic conditions during deposition, including the presence of pyrite framboids with a size distribution suggesting syngenetic formation in the water column, and enrichments in several trace elements, including molybdenum, arsenic, copper, zinc, and chromium. Molybdenum enrichments are clearly associated with enrichments in manganese and authigenic iron, suggesting "shuttling" of redox sensitive trace elements across a chemocline that fluctuated across the sediment-water interface. Comparisons with modern systems suggest relatively high-frequency redox variability, possibly over approximately annual timescales, which may be related to the annual cycle of polar sunlight and associated seasonal changes in primary productivity. Glauconitic horizons are associated with more reducing conditions, including at the K-Pg boundary, though this does not appear to be a uniquely euxinic interval; similar degrees of trace element enrichment are seen in other highly glauconitic intervals. While euxinia may have contributed to low diversity in the lowermost 'Rotularia Units', redox conditions do not seem to have been the primary control on the transition to a mollusc dominated fauna in the latest Maastrichtian. Redox conditions show little to no response to the eruption of the Deccan Traps or Maastrichtian climatic changes. Instead, intermittent euxinia appears to have been a characteristic feature of this high-latitude environment during the Cretaceous-Paleogene transition.

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Section: Stratigraphysupporting

confidence: 66%