Last Glacial central Mediterranean hydrology inferred from Lake Trasimeno’s (Italy) calcium carbonate geochemistry

Abstract. The new sediment record from the deep Dead Sea basin (ICDP core 5017-1) provides a unique archive for hydroclimatic variability in the Levant. Here, we present high-resolution sediment facies analysis and elemental composition by micro-X-ray fluorescence (µXRF) scanning of core 5017-1 to trace lake levels and responses of the regional hydroclimatology during the time interval from ca. 117 to 75 ka, i.e. the transition between the last interglacial and the onset of the last glaciation. We distinguished six major micro-facies types and interpreted these and their alterations in the core in terms of relative lake level changes. The two end-member facies for highest and lowest lake levels are (a) up to several metres thick, greenish sediments of alternating aragonite and detrital marl laminae (aad) and (b) thick halite facies, respectively. Intermediate lake levels are characterised by detrital marls with varying amounts of aragonite, gypsum or halite, reflecting lower-amplitude, shorter-term variability. Two intervals of pronounced lake level drops occurred at ∼  110–108 ± 5 and ∼  93–87 ± 7 ka. They likely coincide with stadial conditions in the central Mediterranean (Melisey I and II pollen zones in Monticchio) and low global sea levels during Marine Isotope Stage (MIS) 5d and 5b. However, our data do not support the current hypothesis of an almost complete desiccation of the Dead Sea during the earlier of these lake level low stands based on a recovered gravel layer. Based on new petrographic analyses, we propose that, although it was a low stand, this well-sorted gravel layer may be a vestige of a thick turbidite that has been washed out during drilling rather than an in situ beach deposit. Two intervals of higher lake stands at ∼  108–93 ± 6 and ∼  87–75 ± 7 ka correspond to interstadial conditions in the central Mediterranean, i.e. pollen zones St. Germain I and II in Monticchio, and Greenland interstadials (GI) 24+23 and 21 in Greenland, as well as to sapropels S4 and S3 in the Mediterranean Sea. These apparent correlations suggest a close link of the climate in the Levant to North Atlantic and Mediterranean climates during the time of the build-up of Northern Hemisphere ice shields in the early last glacial period.

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Episodic, rapid sea-level rises on the central Mediterranean shelves after the Last Glacial Maximum: A review

Marine Geology ◽

10.1016/j.margeo.2015.09.002 ◽

2015 ◽

Vol 369 ◽

pp. 212-223 ◽

Cited By ~ 22

Author(s):

Massimo Zecchin ◽

Silvia Ceramicola ◽

Emanuele Lodolo ◽

Daniele Casalbore ◽

Francesco Latino Chiocci

Keyword(s):

Sea Level ◽

Last Glacial Maximum ◽

Glacial Maximum ◽

Central Mediterranean ◽

Last Glacial ◽

The Last Glacial Maximum ◽

The Last Glacial

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Calcium carbonate corrosiveness in the South Atlantic during the Last Glacial Maximum as inferred from changes in the preservation of Globigerina bulloides: A proxy to determine deep-water circulation patterns?

Marine Geology ◽

10.1016/s0025-3227(03)00372-4 ◽

2004 ◽

Vol 204 (1-2) ◽

pp. 43-57 ◽

Cited By ~ 28

Author(s):

A.N.A Volbers ◽

R Henrich

Keyword(s):

Calcium Carbonate ◽

Last Glacial Maximum ◽

Deep Water ◽

Glacial Maximum ◽

Water Circulation ◽

Last Glacial ◽

Globigerina Bulloides ◽

Circulation Patterns ◽

The Last Glacial Maximum ◽

The Last Glacial

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Hydroclimatic variability in the Levant during the early last glacial (∼ 117–75 ka) derived from micro-facies analyses of deep Dead Sea sediments

Climate of the Past Discussions ◽

10.5194/cpd-11-3625-2015 ◽

2015 ◽

Vol 11 (4) ◽

pp. 3625-3663 ◽

Cited By ~ 4

Author(s):

I. Neugebauer ◽

M. J. Schwab ◽

N. D. Waldmann ◽

R. Tjallingii ◽

U. Frank ◽

...

Keyword(s):

Lake Level ◽

Dead Sea ◽

Lake Levels ◽

Last Interglacial ◽

Central Mediterranean ◽

Close Link ◽

Last Glacial ◽

Gravel Layer ◽

Lower Amplitude ◽

Hydroclimatic Variability

Abstract. The new sediment record from the deep Dead Sea basin (ICDP core 5017-1) provides a unique archive for hydroclimatic variability in the Levant. Here, we present high-resolution sediment facies analysis and elemental composition by μXRF scanning of core 5017-1 to trace lake levels and responses of the regional hydroclimatology during the time interval from ca 117–75 ka, i.e. the transition between the last interglacial and the onset of the last glaciation. We distinguished six major micro-facies types and interpreted these and their alterations in the core in terms of relative lake level changes. The two end-member facies for highest and lowest lake levels are (a) up to several meters thick, greenish sediments of alternating aragonite and detrital marl laminae (aad) and (b) thick halite facies, respectively. Intermediate lake levels are characterised by detrital marls with varying amounts of aragonite, gypsum or halite, reflecting lower-amplitude, shorter-term variability. Two intervals of pronounced lake level drops occurred at ∼110–108 ± 5 and ∼93–87 ± 7 ka. They likely coincide with stadial conditions in the central Mediterranean (Melisey I and II pollen zones in Monticchio) and low global sea levels during MIS 5d and 5b. However, our data do not support the current hypothesis of an almost complete desiccation of the Dead Sea during the earlier of these lake level low stands based on a recovered gravel layer. Based on new petrographic analyses, we propose that, although it was a low stand, this well-sorted gravel layer may be a vestige of a thick turbidite that has been washed out during drilling rather than an in-situ beach deposit. Two intervals of higher lake stands at ∼108–93 ± 6 and ∼87–75 ± 7 ka correspond to interstadial conditions in the central Mediterranean, i.e. pollen zones St. Germain I and II in Monticchio, and GI 24 + 23 and 21 in Greenland, as well as to sapropels S4 and S3 in the Mediterranean Sea. These apparent correlations suggest a close link of the climate in the Levant to North Atlantic and Mediterranean climates during the time of the build-up of Northern Hemisphere ice shields in the early last glacial period.

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Tracking atmospheric and riverine terrigenous supplies variability during the last glacial and the Holocene in central Mediterranean

Climate of the Past Discussions ◽

10.5194/cpd-8-2921-2012 ◽

2012 ◽

Vol 8 (4) ◽

pp. 2921-2968 ◽

Cited By ~ 2

Author(s):

V. Bout-Roumazeilles ◽

N. Combourieu-Nebout ◽

S. Desprat ◽

G. Siani ◽

J.-L. Turon

Keyword(s):

North Africa ◽

Large Scale ◽

Fine Particles ◽

Intermediate Water ◽

Central Mediterranean ◽

Inter Tropical Convergence Zone ◽

The Holocene ◽

Last Glacial ◽

Southern Side ◽

The Last Glacial

Abstract. The objectives were to retrace the eolian and fluvial terrigenous supplies in a sediment core from the Sicilian-Tunisian Strait by coupling mineralogical, grain-size and geochemical approaches, in order to get informations on the atmospheric versus riverine contributions to sedimentation on the southern side of central Mediterranean since the last glacial. The eolian supply is dominant over the whole interval, excepted during the sapropel S1 when riverine contribution apparently became significant, and particles provenance has been modified since Last Glacial. Saharan contribution increased during the Bølling-Allerød, evidencing the persistence of aridity over North Africa although the northern Mediterranean already experienced moister and warmer conditions. The Younger Dryas is marked by proximal dust inputs highlighting intense regional eolian activity. A southward migration of dust provenance toward Sahel occurred at the onset of the Holocene, likely resulting from a southward position of the Inter Tropical Convergence Zone, probably associated with a large-scale atmospheric reorganization. Finally, a peculiar high terrigenous flux associated with drastic modifications of the mineralogical and geochemical sediment signature occurred during the sapropel S1, suggesting the propagation of fine-particles derived from major floodings of the Nile River – resulting from enhanced rainfall on northeastern Africa – and their transportation across the Sicilian-Tunisian Strait by intermediate water-masses.

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The Y-3 tephra: A Last Glacial stratigraphic marker for the central Mediterranean basin

Journal of Volcanology and Geothermal Research ◽

10.1016/j.jvolgeores.2007.08.017 ◽

2008 ◽

Vol 177 (1) ◽

pp. 145-154 ◽

Cited By ~ 49

Author(s):

G. Zanchetta ◽

R. Sulpizio ◽

B. Giaccio ◽

G. Siani ◽

M. Paterne ◽

...

Keyword(s):

Mediterranean Basin ◽

Central Mediterranean ◽

Last Glacial

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Tracking atmospheric and riverine terrigenous supplies variability during the last glacial and the Holocene in central Mediterranean

Climate of the Past ◽

10.5194/cp-9-1065-2013 ◽

2013 ◽

Vol 9 (3) ◽

pp. 1065-1087 ◽

Cited By ~ 33

Author(s):

V. Bout-Roumazeilles ◽

N. Combourieu-Nebout ◽

S. Desprat ◽

G. Siani ◽

J.-L. Turon ◽

...

Keyword(s):

North Africa ◽

Large Scale ◽

Fine Particles ◽

Nile River ◽

Intermediate Water ◽

Central Mediterranean ◽

Inter Tropical Convergence Zone ◽

The Holocene ◽

Last Glacial ◽

The Last Glacial

Abstract. A multiproxy study – coupling mineralogical, grain size and geochemical approaches – was used to tentatively retrace eolian and fluvial contributions to sedimentation in the Sicilian–Tunisian Strait since the last glacial. The eolian supply is dominant over the whole interval, excepted during the sapropel S1 when riverine contribution apparently became significant. Saharan contribution increased during the Bølling–Allerød, evidencing the persistence of aridity over North Africa although the northern Mediterranean already experienced moister and warmer conditions. The Younger Dryas is marked by proximal dust inputs, highlighting intense regional eolian activity. A southward migration of dust provenance toward Sahel occurred at the onset of the Holocene, likely resulting from a southward position of the Inter Tropical Convergence Zone that was probably associated with a large-scale atmospheric reorganization. Finally, a peculiar high terrigenous flux associated with drastic modifications of the mineralogical and geochemical sediment signature occurred during the sapropel S1, suggesting the propagation of fine particles derived from major floodings of the Nile River – resulting from enhanced rainfall on northeastern Africa – and their transportation across the Sicilian–Tunisian Strait by intermediate water masses.

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A TEM study of the microstructure of avian eggshells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130146 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1102-1103

Author(s):

S. Q. Xiao ◽

S. Baden ◽

A. H. Heuer

Keyword(s):

Electron Microscope ◽

Calcium Carbonate ◽

Nucleation And Growth ◽

Growth Mechanisms ◽

Shell Surface ◽

Thin Sections ◽

Polycrystalline Metals ◽

Transmission Electron ◽

Nucleation And Growth Mechanisms

The avian eggshell is one of the most rapidly mineralizing biological systems known. In situ, 5g of calcium carbonate are crystallized in less than 20 hrs to fabricate the shell. Although there have been much work about the formation of eggshells, controversy about the nucleation and growth mechanisms of the calcite crystals, and their texture in the eggshell, still remain unclear. In this report the microstructure and microchemistry of avian eggshells have been analyzed using transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS).Fresh white and dry brown eggshells were broken and fixed in Karnosky's fixative (kaltitanden) for 2 hrs, then rinsed in distilled H2O. Small speckles of the eggshells were embedded in Spurr medium and thin sections were made ultramicrotome.The crystalline part of eggshells are composed of many small plate-like calcite grains, whose plate normals are approximately parallel to the shell surface. The sizes of the grains are about 0.3×0.3×1 μm3 (Fig.l). These grains are not as closely packed as man-made polycrystalline metals and ceramics, and small gaps between adjacent grains are visible indicating the absence of conventional grain boundaries.

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