GLORIA — GEOMAR Library Ocean Research Information Access

1

Digitale Medien

Geological evaluation of climate General Circulation Models and model implications for Mesozoic cloud cover (1997)

Sellwood, Bruce W. ; Valdes, Paul J.

Oxford, UK : Blackwell Publishing Ltd

Terra nova 9 (1997), S. 0

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ISSN: 1365-3121

Quelle: Blackwell Publishing Journal Backfiles 1879-2005

Thema: Geologie und Paläontologie

Notizen: General Circulation Models (GCMs) are currently used to predict future global change. However, the robustness of GCMs can, and should, be evaluated by their ability to simulate past climate regimes. Their success in ‘retrodiction’ can then be assessed by reference to the testimony of the geological record. Geological evidence provides a database which can be used in the estimation of sea surface temperatures and other proxy data useful in palaeoclimatic studies. These data can then be used to refine the prescribed boundary conditions for running GCMs themselves. Results of modelling experiments confirm a generally warmer Mesozoic earth with arid tropics and convective rainfall higher over the oceans than at present. Circum-polar wetlands are also indicated. Modelled cloudiness is also higher in the Mesozoic, contributing to greenhouse conditions and possibly influencing terrestrial biomes and marine ecosystems.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1111/j.1365-3121.1997.tb00006.x

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2

Digitale Medien

Constant elevation of southern Tibet over the past 15 million years (2003)

Harris, Nigel B. W. ; Widdowson, Mike ; Herman, Alexei B. ; [weitere]

[s.l.] : Macmillian Magazines Ltd.

Nature 421 (2003), S. 622-624

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ISSN: 1476-4687

Quelle: Nature Archives 1869 - 2009

Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik

Notizen: [Auszug] The uplift of the Tibetan plateau, an area that is 2,000 km wide, to an altitude of about 5,000 m has been shown to modify global climate and to influence monsoon intensity. Mechanical and thermal models for homogeneous thickening of the lithosphere make specific predictions about ...

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1038/nature01356

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3

Digitale Medien

Atmospheric equilibrium, instability and energy transport at the last glacial maximum (1996)

Hall, Nicholas M. J. ; Doug, Buwen ; Valdes, Paul J.

Springer

Climate dynamics 12 (1996), S. 497-511

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ISSN: 1432-0894

Quelle: Springer Online Journal Archives 1860-2000

Thema: Geologie und Paläontologie , Physik

Notizen: Abstract A range of diagnostics from two GCM simulations, one of the present-day climate and one of the last glacial maximum (LGM) is used to gain insight into their different temperature structures and eddy dynamics. There are large local increases in baroclinicity at the LGM, especially in the Atlantic storm track, with large accompanying increases in the low level transient eddy heat flux. However, the differences in the zonal mean are much smaller, and the increases in both baroclinicity and heat flux are confined to low levels. Supplementary experiments with baroclinic wave lifecycles confirm the marked contrast between local and zonal mean behaviour, but do not adequately explain the differences between the zonal mean climates. The total flux of energy across latitude circles in the Northern Hemisphere does not change much during DJF, although its transient component is actually reduced at the LGM (during JJA the transient component is increased). Calculations of total linear eddy diffusivity reveal that changes in the time mean stationary waves are chiefly responsible for the seasonal range of this quantity at the LGM, while they only account for half the seasonal range at the present-day.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/BF02346821

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4

Digitale Medien

Atmospheric equilibrium, instability and energy transport at the last glacial maximum (1996)

Hall, Nicholas M. J. ; Dong, Buwen ; Valdes, Paul J.

Springer

Climate dynamics 12 (1996), S. 497-511

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ISSN: 1432-0894

Quelle: Springer Online Journal Archives 1860-2000

Thema: Geologie und Paläontologie , Physik

Notizen: Abstract. A range of diagnostics from two GCM simulations, one of the present-day climate and one of the last glacial maximum (LGM) is used to gain insight into their different temperature structures and eddy dynamics. There are large local increases in baroclinicity at the LGM, especially in the Atlantic storm track, with large accompanying increases in the low level transient eddy heat flux. However, the differences in the zonal mean are much smaller, and the increases in both baroclinicity and heat flux are confined to low levels. Supplementary experiments with baroclinic wave lifecycles confirm the marked contrast between local and zonal mean behaviour, but do not adequately explain the differences between the zonal mean climates. The total flux of energy across latitude circles in the Northern Hemisphere does not change much during DJF, although its transient component is actually reduced at the LGM (during JJA the transient component is increased). Calculations of total linear eddy diffusivity reveal that changes in the time mean stationary waves are chiefly responsible for the seasonal range of this quantity at the LGM, while they only account for half the seasonal range at the present-day.

Materialart: Digitale Medien

URL: http://dx.doi.org/10.1007/s003820050123

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5

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Thin-section and isotope data from the Lakadong Limestone, NE India (eastern Tethys) (2022)

Sarkar, Suman ; Cotton, Laura ; Valdes, Paul J ; [weitere]

PANGAEA

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Publikationsdatum: 2023-01-30

Beschreibung: The Paleocene Eocene Thermal Maximum (PETM) is associated with major extinction events in the deep ocean, and significant paleogeographic and ecological changes in surface ocean and terrestrial environments. However, the impact of the associated environmental change on shelf biota is less well understood. Here we present a new PETM record of a low paleolatitude late Paleocene-earliest Eocene shallow-marine carbonate platform from Meghalaya, NE India (eastern Tethys). The biotic assemblage was distinctly different to other Tethyan PETM records dominated by larger benthic foraminifera and calcareous algae both in the Paleocene and Eocene. The record is lacking the ecological change from corals to larger foraminiferal assemblages and the Lockhartia dominance, characteristic of other sections in the Tethys. Limestone samples were collected at very high resolution of up to 10 cm from the carbonate successions outcropping in the Mawmluh Cement quarry (25°15.707' N; 91°42.626' E), East Khasi Hills, Meghalaya, NE India. Petrographic thin-sections were prepared from the limestone samples for the light and scanning electron microscopic analysis of the biotic components. In addition to LBF biostratigraphy, carbon isotope analysis was carried out for correlating the shallow benthic zones with the carbon isotope excursion (CIE) for developing a polished record of the PETM. An CIE of ~-3‰ (from 1.96 to -1.08 ‰) tied into the biostratigraphy places the PETM towards the upper part of the Lakadong Limestone from 25.0 to 30.5 m. A change in taxa and forms indicating deeper waters with a concurrent decrease in abundance of shallow water algae suggested a sea-level rise during the onset of the PETM. Oxygen isotope analysis indicated signs of diagenetic overprint in the studied succession.

Schlagwort(e): Benthic foraminifera; coralline algae; isotope data; Paleocene-Eocene Thermal Maximum; thin-section

Materialart: Dataset

Format: application/zip, 3 datasets

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6

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Sea surface temperature reconstruction for sediment core MD02-2515

McClymont, Erin L ; Ganeshram, Raja S ; Pichevin, Laetitia ; [weitere]

PANGAEA

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Publikationsdatum: 2023-06-27

Schlagwort(e): AGE; Calculated from TEX86 (Kim et al., 2010); Calculated from UK'37 (Müller et al, 1998); CALYPSO; Calypso Corer; Guaymas Basin; IMAGES VIII - MONA; Marion Dufresne (1995); MD022515; MD02-2515; MD126; Sea surface temperature, annual mean

Materialart: Dataset

Format: text/tab-separated-values, 506 data points

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7

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(Table 1) Age determination of sediment core MD02-2515

McClymont, Erin L ; Ganeshram, Raja S ; Pichevin, Laetitia ; [weitere]

PANGAEA

In: Supplement to: McClymont, Erin L; Ganeshram, Raja S; Pichevin, Laetitia; Talbot, Helen M; van Dongen, Frank H; Thunell, Robert C; Haywood, Alan M; Singarayer, Joy S; Valdes, Paul J (2012): Sea-surface temperature records of Termination 1 in the Gulf of California: Challenges for seasonal and interannual analogues of tropical Pacific climate change. Paleoceanography, 27(2), PA2202, https://doi.org/10.1029/2011PA002226

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Publikationsdatum: 2023-06-27

Beschreibung: Centennial-scale records of sea-surface temperature and opal composition spanning the Last Glacial Maximum and Termination 1 (circa 25-6 ka) are presented here from Guaymas Basin in the Gulf of California. Through the application of two organic geochemistry proxies, the UK37' index and the TEX86H index, we present evidence for rapid, stepped changes in temperatures during deglaciation. These occur in both temperature proxies at 13 ka (~3°C increase in 270 years), 10.0 ka (~2°C decrease over ~250 years) and at 8.2 ka (3°C increase in 〈200 years). An additional rapid warming step is also observed in TEX86H at 11.5 ka. In comparing the two temperature proxies and opal content, we consider the potential for upwelling intensity to be recorded and link this millennial-scale variability to shifting Intertropical Convergence Zone position and variations in the strength of the Subtropical High. The onset of the deglacial warming from 17 to 18 ka is comparable to a "southern hemisphere" signal, although the opal record mimics the ice-rafting events of the north Atlantic (Heinrich events). Neither the modern seasonal cycle nor El Niño/Southern Oscillation patterns provide valid analogues for the trends we observe in comparison with other regional records. Fully coupled climate model simulations confirm this result, and in combination we question whether the seasonal or interannual climate variations of the modern climate are valid analogues for the glacial and deglacial tropical Pacific.

Schlagwort(e): Age, 14C AMS; Age, 14C milieu/reservoir corrected; Age, dated; Age, dated material; Age, dated standard deviation; Calendar age; CALYPSO; Calypso Corer; DEPTH, sediment/rock; Guaymas Basin; IMAGES VIII - MONA; Marion Dufresne (1995); MD022515; MD02-2515; MD126

Materialart: Dataset

Format: text/tab-separated-values, 56 data points

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8

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Quantifying the stability of planktic foraminiferal physical niches (2017)

Waterson, Amy ; Edgar, Kirsty M ; Schmidt, Daniela N ; [weitere]

PANGAEA

In: Supplement to: Waterson, Amy; Edgar, Kirsty M; Schmidt, Daniela N; Valdes, Paul J (2017): Quantifying the stability of planktic foraminiferal physical niches between the Holocene and Last Glacial Maximum. Paleoceanography, https://doi.org/10.1002/2016PA002964

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Publikationsdatum: 2023-07-07

Beschreibung: The application of transfer functions on fossil assemblages to reconstruct past environments is fundamentally based on the assumption of stable environmental niches in both space and time. We quantitatively test this assumption for six dominant planktic foraminiferal species (Globigerinoides ruber (pink), G. ruber (white), Trilobatus sacculifer, Truncorotalia truncatulinoides, Globigerina bulloides and Neogloboquadrina pachyderma) by contrasting reconstructions of species realised and optimum distributions in the modern and during the Last Glacial Maximum (LGM) using an ecological niche model (ENM; MaxEnt) and ordination framework. Global ecological niche models calibrated in the modern ocean have high predictive performance when projected to the LGM for sub-polar and polar species, indicating that the environmental niches of these taxa are largely stable at the global scale across this interval. In contrast, ENM's had much poorer predictive performance for the optimal niche of tropical-dwelling species, T. sacculifer and G. ruber (pink). This finding is supported by independent metrics of niche margin change, suggesting that niche stability in environmental space was greatest for (sub)polar species, with greatest expansion of the niche observed for tropical species. We find that globally calibrated ENMs showed good predictions of species occurrences globally, whereas models calibrated in either the Pacific or Atlantic Oceans only and then projected globally performed less well for T. sacculifer. Our results support the assumption of environmental niche stability over the last ~21,000 years for most of our focal planktic foraminiferal species and thus, the application of transfer function techniques for palaeoenvironmental reconstruction during this interval. However, the lower observed niche stability for (sub)tropical taxa T. sacculifer and G. ruber (pink) suggests that (sub)tropical temperatures could be underestimated in the glacial ocean with the strongest effect in the equatorial Atlantic where both species are found today.

Schlagwort(e): File content; File format; File name; File size; Uniform resource locator/link to file

Materialart: Dataset

Format: text/tab-separated-values, 70 data points

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Terrestrial environmental change across the onset of the PETM and the associated impact on biomarker proxies: a cautionary tale (2019)

Inglis, Gordon N ; Farnsworth, Alexander ; Collinson, Margaret E ; [weitere]

PANGAEA

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Publikationsdatum: 2023-08-11

Beschreibung: The following supplementary information includes one dataset which contains 3 tables: Biomarker distributions and proxies at Cobham, UK Bulk and compound specific isotope data at Cobham (UK) Model-derived mean annual surface temperature and precipitation estimates as a function of CO2 at Cobham (UK).

Schlagwort(e): lignite

Materialart: Dataset

Format: application/zip, 3 datasets

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Biomarker distributions and proxies at Cobham, UK (2023)

Inglis, Gordon N ; Farnsworth, Alexander ; Collinson, Margaret E ; [weitere]

PANGAEA

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Publikationsdatum: 2023-08-11

Schlagwort(e): Acyclic glycerol dialkyl glycerol tetraether, fractional abundance; Acyclic glycerol dialkyl glycerol tetraether (peak intensity); Age, comment; Branched and isoprenoid tetraether index; Branched glycerol dialkyl glycerol tetraether; Branched glycerol dialkyl glycerol tetraether, Ia, fractional abundance; Branched glycerol dialkyl glycerol tetraether, Ia (peak area); Branched glycerol dialkyl glycerol tetraether, Ib, fractional abundance; Branched glycerol dialkyl glycerol tetraether, Ib (peak area); Branched glycerol dialkyl glycerol tetraether, Ic, fractional abundance; Branched glycerol dialkyl glycerol tetraether, Ic (peak area); Branched glycerol dialkyl glycerol tetraether, IIa, fractional abundance; Branched glycerol dialkyl glycerol tetraether, IIa', fractional abundance; Branched glycerol dialkyl glycerol tetraether, IIa' (peak area); Branched glycerol dialkyl glycerol tetraether, IIa (peak area); Branched glycerol dialkyl glycerol tetraether, IIb, fractional abundance; Branched glycerol dialkyl glycerol tetraether, IIb', fractional abundance; Branched glycerol dialkyl glycerol tetraether, IIb' (peak area); Branched glycerol dialkyl glycerol tetraether, IIb (peak area); Branched glycerol dialkyl glycerol tetraether, IIc, fractional abundance; Branched glycerol dialkyl glycerol tetraether, IIc', fractional abundance; Branched glycerol dialkyl glycerol tetraether, IIc' (peak area); Branched glycerol dialkyl glycerol tetraether, IIc (peak area); Branched glycerol dialkyl glycerol tetraether, IIIa, fractional abundance; Branched glycerol dialkyl glycerol tetraether, IIIa', fractional abundance; Branched glycerol dialkyl glycerol tetraether, IIIa' (peak area); Branched glycerol dialkyl glycerol tetraether, IIIa (peak area); Branched glycerol dialkyl glycerol tetraether, IIIb, fractional abundance; Branched glycerol dialkyl glycerol tetraether, IIIb', fractional abundance; Branched glycerol dialkyl glycerol tetraether, IIIb' (peak area); Branched glycerol dialkyl glycerol tetraether, IIIb (peak area); Branched glycerol dialkyl glycerol tetraether, IIIc, fractional abundance; Branched glycerol dialkyl glycerol tetraether, IIIc', fractional abundance; Branched glycerol dialkyl glycerol tetraether, IIIc' (peak area); Branched glycerol dialkyl glycerol tetraether, IIIc (peak area); Branched glycerol monoalkyl glycerol tetraethers, Ia (peak area); Branched glycerol monoalkyl glycerol tetraethers, IIa (peak area); Branched glycerol monoalkyl glycerol tetraethers, IIIa (peak area); Cobham; Comment; Crenarchaeol, fractional abundance; Crenarchaeol (peak area); Degree of cyclisation; DEPTH, sediment/rock; Dicyclic glycerol dialkyl glycerol tetraether, fractional abundance; Dicyclic glycerol dialkyl glycerol tetraether (peak area); Glycerol dialkyl glycerol tetraether 5 (peak area); Glycerol monoalkyl glycerol tetraether lipids; Glycerol monoalkyl glycerol tetraether lipids (peak area); H-Glycerol dialkyl glycerol tetraether (peak area); Isoprenoid glycerol dialkyl glycerol tetraether, 5; lignite; Lithology/composition/facies; Methylation index of branched tetraethers; Monocyclic glycerol dialkyl glycerol tetraether, fractional abundance; Monocyclic glycerol dialkyl glycerol tetraether (peak area); pH; Proxy; QU; Quarry; Sample code/label; Tetracyclic glycerol dialkyl glycerol tetraether, fractional abundance; Tetracyclic glycerol dialkyl glycerol tetraether (peak area); Tricyclic glycerol dialkyl glycerol tetraether, fractional abundance; Tricyclic glycerol dialkyl glycerol tetraether (peak area)

Materialart: Dataset

Format: text/tab-separated-values, 2155 data points

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