Late Quaternary nannofossil indicators of climate change in two deep-sea cores associated with the Leeuwin Current off Western Australia

Okada, Hisatake; Wells, Patricia

doi:10.1016/s0031-0182(97)00014-x

Cited by 113 publications

(63 citation statements)

References 34 publications

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“…The dominance of E. huxleyi in the upper photic zone nannoflora of the Holocene and latest late Pleistocene is well documented both globally (e.g. Matsuoka and Okada, 1989;Rahman and de Vernal, 1994;Okada and Wells, 1997;Flores et al, 1999;Henriksson, 2000;Kinkel et al, 2000;Takahashi and Okada, 2000) and from the Mediterranean (Flores et al, 1997;Aksu et al, 1995a;Sbaffi et al, 2001).…”

Section: Holocene -Latest Late Pleistocene Reticulofenestridsmentioning

confidence: 93%

Abnormal carbonate diagenesis in Holocene–late Pleistocene sapropel-associated sediments from the Eastern Mediterranean; evidence from Emiliania huxleyi coccolith morphology

Crudeli

Young

Erba

et al. 2004

Marine Micropaleontology

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In studying the Holocene -late Pleistocene record of the Eastern Mediterranean, considerable Emiliania huxleyi size/shape variation not clearly assignable to primary or secondary calcification was observed. Accordingly, different morphotypes were distinguished by light microscope (LM).A subsequent scanning electron microscope (SEM) analysis of selected samples has indicated that Emiliania huxleyi coccoliths are variably affected by carbonate diagenesis in these sediments. A series of diagenetic stages were qualitatively defined, comprising well-preserved specimens, three overgrowth (OG1 to OG3) and one etching (E1) stage. Comparing SEM and LM observations, a tentative correlation between the E. huxleyi calcified LM-morphotypes and E. huxleyi SEM-overgrowth stages is proposed here.Our study not only indicates that Emiliania huxleyi coccoliths are strongly influenced by carbonate diagenesis, but also that they show effects of carbonate precipitation and dissolution much more clearly than other coccoliths. The relative abundances of the different LM-morphotypes were used to define an E. huxleyi overgrowth index (EXO) that qualitatively estimates carbonate precipitation/dissolution on coccoliths in this sediment. This resulted in definition of five ''Diagenetic'' intervals (D1 to D5). Deposition of sapropel S1 was a time of good preservation with variable dissolution and no overgrowth of E. huxleyi coccoliths, whereas calcite overgrowth was high during the Last Glacial Maximum (LGM) and interglacial period and, to a lesser extent, during the Younger Dryas and through the last 5 ka. D

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Section: Holocene -Latest Late Pleistocene Reticulofenestridsmentioning

confidence: 93%

Abnormal carbonate diagenesis in Holocene–late Pleistocene sapropel-associated sediments from the Eastern Mediterranean; evidence from Emiliania huxleyi coccolith morphology

Crudeli

Young

Erba

et al. 2004

Marine Micropaleontology

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“…This is caused by a decline in the strength of the LC, caused by a reduced ITF leading to the increased dominance of the cooler West Australian Undercurrent (Wells et al, 1994;Wells and Okada, 1996;Okada and Wells, 1997;Martinez et al, 1999;Takahashi and Okada, 2000 There is some evidence for pulses of upwelling bringing nutrient rich water to the west coast of Australia during the LGM (Wells et al, 1994;Rogers and De Deckker, 2007), but it is unlikely that there was ever a fully developed upwelling system comparable to other eastern boundary currents in the Southern Hemisphere. The latitudinal limit of the reduced LC during the LGM is equivocal with Barrows and Juggins (2005) using foraminiferal assemblages to suggest that the LC probably reached as far as 32°S, while Takahashi and Okada (2000) used calcareous nanofossils to show that it did not reach as far south as 24°S.…”

Section: Last Glacial Maximum (Lgm) ~22-18 Kamentioning

confidence: 99%

Climatic records over the past 30 ka from temperate Australia – a synthesis from the Oz-INTIMATE workgroup

Petherick

Bostock

Cohen

et al. 2013

Quaternary Science Reviews

119

122

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Dosseto, A. (2013). Climatic records over the past 30 ka from temperate Australia -a synthesis from the Oz-INTIMATE workgroup. Quaternary Science Reviews, 74 58-77.Climatic records over the past 30 ka from temperate Australia -a synthesis from the Oz-INTIMATE workgroup AbstractTemperate Australia sits between the heat engine of the tropics and the cold Southern Ocean, encompassing a range of rainfall regimes and falling under the influence of different climatic drivers. Despite this heterogeneity, broad-scale trends in climatic and environmental change are evident over the past 30 ka. During the early glacial period (∼30-22 ka) and the Last Glacial Maximum (∼22-18 ka), climate was relatively cool across the entire temperate zone and there was an expansion of grasslands and increased fluvial activity in regionally important Murray-Darling Basin. The temperate region at this time appears to be dominated by expanded sea ice in the Southern Ocean forcing a northerly shift in the position of the oceanic fronts and a concomitant influx of cold water along the southeast (including Tasmania) and southwest Australian coasts. The deglacial period (∼18-12 ka) was characterised by glacial recession and eventual disappearance resulting from an increase in temperature deduced from terrestrial records, while there is some evidence for climatic reversals (e.g. the Antarctic Cold Reversal) in high resolution marine sediment cores through this period. The high spatial density of Holocene terrestrial records reveals an overall expansion of sclerophyll woodland and rainforest taxa across the temperate region after ∼12 ka, presumably in response to increasing temperature, while hydrological records reveal spatially heterogeneous hydro-climatic trends. Patterns after ∼6 ka suggest higher frequency climatic variability that possibly reflects the onset of large scale climate variability caused by the El Niño/Southern Oscillation. Petherick, L., Bostock, H., Cohen, T. J., Fitzsimmons, K., Tibby, J., Fletcher, M. -S., Moss, P., Reeves, J., Mooney, S., Barrows, T., Kemp, J., Jansen, J., Nanson, G. & Dosseto, A. (2013). Climatic records over the past 30 ka from temperate Australia -a synthesis from the Oz-INTIMATE workgroup. Quaternary Science Reviews, 74 58-77. Australian coasts. The deglacial period (~18-12 ka) was characterised by glacial recession and eventual disappearance resulting from an increase in temperature deduced from terrestrial records, while there is some evidence for climatic reversals (e.g. the Antarctic Cold Reversal) in high resolution marine sediment cores through this period. The high spatial density of Holocene terrestrial records reveals an overall expansion of sclerophyll woodland and rainforest taxa across the temperate region after ~12 ka, presumably in response to increasing temperature, while hydrological records reveal spatially heterogeneous hydro-climatic trends. Patterns after ~6 ka suggest higher frequency climatic variability that possibly reflects the onset of large scale climate variability caused by...

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“…e Gephyrocapsa oceanica têm sua abundância diretamente influenciada pelo fortalecimento e enfraquecimento deste fenômeno oceanográfico (Giraudeau, 1992;Ziveri et al, 1995;Okada & Wells, 1997;Álvarez et al, 2010), sendo também os táxons de maior representatividade nestes sistemas. (Maciel, 2008;Tokutake, 2005;Toledo et al, 2002).…”

Section: Nas Principais áReas De Ressurgência Os Táxons Emiliania Huxunclassified

“…Deise de Oliveira Delfino & Maria Dolores Wanderley espécie que habita exclusivamente a zona fótica inferior (Okada & Honjo, 1973) e que tem sido reconhecida como uma poderosa ferramenta para a paleoceanografia do Quaternário (Okada & Wells, 1997). A abundância relativa deste táxon pode ser utilizada como indicador de paleoprofundidade da água, transparência média da água (Ahagon et al, 1993) e mudanças na estrutura vertical dos oceanos (Molfino & McIntyre, 1990;Castradori, 1993).…”

Section: Nanofósseis Calcários Da áRea De Ressurgência De Cabo Frio unclassified

Nanofósseis Calcários da Área de Ressurgência de Cabo Frio, Brasil

Delfino

Wanderley

2013

Anuário IGEO-UFRJ

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Late Quaternary nannofossil indicators of climate change in two deep-sea cores associated with the Leeuwin Current off Western Australia

Cited by 113 publications

References 34 publications

Abnormal carbonate diagenesis in Holocene–late Pleistocene sapropel-associated sediments from the Eastern Mediterranean; evidence from Emiliania huxleyi coccolith morphology

Abnormal carbonate diagenesis in Holocene–late Pleistocene sapropel-associated sediments from the Eastern Mediterranean; evidence from Emiliania huxleyi coccolith morphology

Climatic records over the past 30 ka from temperate Australia – a synthesis from the Oz-INTIMATE workgroup

Nanofósseis Calcários da Área de Ressurgência de Cabo Frio, Brasil

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