North-African paleodrainage discharges to the central Mediterranean during the last 18,000 years: A multiproxy characterization

Wu, Jiawang; Liu, Zhifei; Stuut, Jan‐Berend; Zhao, Yulong; Schirone, Antonio; Lange, Gert J. de

doi:10.1016/j.quascirev.2017.03.015

Cited by 29 publications

(54 citation statements)

References 113 publications

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“…The organic carbon content was measured with a Fisons NA1500 CNS elemental analyzer using samples decarbonated with 1 M HCl (4 and 12 hr; cf. Wu et al, ), The average standard deviation for international and laboratory standards was better than 1%.…”

Section: Methodsmentioning

confidence: 97%

Eastern Mediterranean Deep Water Formation During Sapropel S1: A Reconstruction Using Geochemical Records Along a Bathymetric Transect in the Adriatic Outflow Region

Filippidi

Lange

2019

Paleoceanog and Paleoclimatol

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Eastern Mediterranean thermohaline circulation is directly influenced by middle‐ and low‐latitude climate systems. The dramatic paleoclimate changes during the last African Humid Period (~10–6 ka BP) were captured in Mediterranean sediments as the distinctly organic‐rich unit sapropel S1. Here, deepwater formation variability during S1 deposition is reconstructed. We use geochemical records of three cores along a bathymetric transect (775‐, 1,359‐, and 1,908‐m water depths), at the transition between the Adriatic DW‐ formation area and the Eastern Mediterranean. In all three cores, sedimentation rates are distinctly higher during S1, corresponding with enhanced runoff emanating from the Adriatic hinterland. Hence, major runoff did not only come from southern but also from northern borderlands in this period. During sapropel formation, enhanced levels of primary productivity occurred in the surface waters and oxygen‐depleted conditions in the bottom waters for all sites. Conditions for sediment and bottom‐water below ~1.4 km water depth were sulfidic throughout S1, but for intermediate depth (775 m) were anoxic only during the first part (S1a). Bottom‐water oxygenation interrupted S1 formation at water depths down to ~1.4 km, during two brief episodes, at 8.2 and 7.4 cal. ka BP. From the 7.4 cal. ka BP ventilation onward, the transition to more oxygenated bottom‐water conditions was more progressive for the intermediate water depth site (775 m) than for the deeper sites. Conditions remained fully oxic for all water depths following the S1‐MarkerBed ventilation event. Possibly, the onset of continuously oxic conditions started slightly earlier at intermediate depth (775 m; 6.6 ± 0.3 cal. ka BP) than at greater depths (1,359 m, 1,908 m; 6.0 ± 0.3 cal. ka BP).

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Section: Methodsmentioning

confidence: 97%

Eastern Mediterranean Deep Water Formation During Sapropel S1: A Reconstruction Using Geochemical Records Along a Bathymetric Transect in the Adriatic Outflow Region

Filippidi

Lange

2019

Paleoceanog and Paleoclimatol

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“…Map of Mediterranean Sea with locations of cores used in study. (a) Mediterranean bathymetry and (b) sea surface circulation schematic (arrows; based on Pinardi et al, , and Rohling et al, ), current drainage system (blue), and potential North African paleodrainage networks (cyan; Vörösmarty et al, ; Pachur, ; Rohling et al, ; Osborne et al, ; Paillou et al, ; Coulthard et al, ; Wu et al, ). Plot generated with Ocean Data View (Schlitzer, ).…”

Section: Approachmentioning

confidence: 99%

Quantification of African Monsoon Runoff During Last Interglacial Sapropel S5

Amies

Rohling

Grant

et al. 2019

Paleoceanog and Paleoclimatol

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Organic‐rich sapropel layers punctuate the eastern Mediterranean sedimentary sequence, recording deep‐sea anoxic events. The timing of sapropel deposition coincides with precession minima, which are associated with the northward migration of the monsoon rain belt over North Africa. The resultant increase in monsoon precipitation over the Sahara caused an increase in low‐δ18O freshwater runoff into eastern Mediterranean surface waters, which is reflected by negative δ18O anomalies in the records of planktic foraminiferal calcite. However, despite extensive research on sapropels, the magnitude of monsoon intensification and freshwater runoff, along with its influence on δ18O, remains elusive. Here, we present a quantification of African monsoon freshwater runoff into the eastern Mediterranean for the period of deposition of last interglacial sapropel S5 (~128.3–121.5 ka). Our method uses a box model of the Mediterranean Sea, which represents different water masses, and has been calibrated using δ18O from planktic foraminiferal species of different depth and seasonal habitats. The model was constrained with existing records of sea level and sea surface temperature then inverted to deconvolve the δ18O signal of the surface‐dwelling foraminiferal species Globigerinoides ruber (w) and calculate the freshwater runoff volume. Our calculated African monsoon runoff suggests large increases in freshwater discharge to the eastern Mediterranean (up to ~8.8 times the modern pre‐Aswan Nile discharge). Rapid onset of S5 deposition following the estimated increase in runoff strongly suggests a preconditioning of the eastern Mediterranean for sapropel deposition. Our study also provides insight into the stratification and warming of eastern Mediterranean surface waters during the S5 interval.

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“…In core CP10, the analyzed cryptotephra was recognized initially through elemental composition of the bulk sediments (Wu et al, 2016(Wu et al, , 2017. It was between 7 and 6.5 cm bsf (sample CP10/7) ( Fig.…”

Section: Sampling and Selection Of Materialsmentioning

confidence: 99%

“…Box core CP10BC (hereafter CP10) was collected during the CORTADO-2011 cruise on the Lybian-Tunisian slope. It is 35.5 cm long and characterized by marly ooze with sapropel S1 as a distinct unit (Wu et al, 2016(Wu et al, , 2017.…”

Section: Introductionmentioning

confidence: 99%

The Late Holocene tephra record of the central Mediterranean Sea: Mapping occurrences and new potential isochrons for the 4.4–2.0 ka time interval

Insinga

Petrosino

Alberico

et al. 2019

J Quaternary Science

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Five cores from the southern Tyrrhenian and Ionian seas were studied for their tephra and cryptotephra content in the 4.4-2.0 ka time interval. The chronological framework for each core was obtained by accelerator mass spectrometry 14 C dating, the occurrence of distinct marker tephra and stratigraphic correlation with adjacent records. Tephrochronology allowed us to correlate the analyzed deposits with tephra markers associated with Somma-Vesuvius (79 AD), Ischia Island (Cretaio), Mt Etna (FG, FL and FS) and Campi Flegrei (Astroni-Agnano Monte Spina) events. For the first time in the marine setting, a large single glass data set is provided for the Late Holocene Etnean marker beds including the FS tephra (ca. 4.3 ka). Moreover, unknown deposits from Lipari (ca. 2.2-2.0 ka) and Vulcano (3.6-3.3 ka) are also recognized at more distal sites than previously reported. These results contribute to improve the high-resolution tephrostratigraphic framework of the central Mediterranean Sea. They also provide new insights into the chemical composition and dispersal pattern of tephras that can be used as inter-archive tools for regional and 'local' stratigraphic correlations and for addressing paleoclimate research.

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North-African paleodrainage discharges to the central Mediterranean during the last 18,000 years: A multiproxy characterization

Cited by 29 publications

References 113 publications

Eastern Mediterranean Deep Water Formation During Sapropel S1: A Reconstruction Using Geochemical Records Along a Bathymetric Transect in the Adriatic Outflow Region

Eastern Mediterranean Deep Water Formation During Sapropel S1: A Reconstruction Using Geochemical Records Along a Bathymetric Transect in the Adriatic Outflow Region

Quantification of African Monsoon Runoff During Last Interglacial Sapropel S5

The Late Holocene tephra record of the central Mediterranean Sea: Mapping occurrences and new potential isochrons for the 4.4–2.0 ka time interval

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