Linking Danube River activity to Alpine Ice-Sheet fluctuations during the last glacial (ca. 33–17 ka BP): Insights into the continental signature of Heinrich Stadials

Martinez-Lamas, Ruth; Toucanne, Samuel; Debret, Maxime; Riboulot, Vincent; Deloffre, Julien; Boissier, Audrey; Chéron, Sandrine; Pitel, Mathilde; Bayon, Germain; Giosan, Liviu; Soulet, Guillaume

doi:10.1016/j.quascirev.2019.106136

Cited by 30 publications

(21 citation statements)

References 182 publications

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“…In three MeBo drilling sites, Riedel et al (2020) describe “sand layers several millimeters in thickness” as “typical” in the deeper units, between 45 and 140 mbsf. The analysis of long‐piston cores also shows the presence of sandy layers of thickness increasing with depth (Martinez‐Lamas et al, 2020). These observations indicate the presence of higher permeability layers within the overall fine grained sediments of the area.…”

Section: Discussionmentioning

confidence: 99%

Irregular BSR: Evidence of an Ongoing Reequilibrium of a Gas Hydrate System

Colin

Ker

Riboulot

et al. 2020

Geophysical Research Letters

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Gas hydrate (GH) systems constitute methane sinks sensitive to environmental changes such as pressure, temperature, and salinity. It remains a matter of debate as to whether the large GH system of the Black Sea has reached a steady state since the last glacial maximum (LGM). We report on an irregular free gas distribution in specific sediment layers marking an irregular bottom-simulating reflector (BSR). This anomalous free gas distribution revealed by very high resolution seismic images, acquired by a deep-towed multichannel seismic system, might be evidence of an ongoing migration of the base of the GH stability zone (GHSZ). We show that the reequilibrium is not occurring homogeneously as overpressure from hydrate dissociation slows their decomposition in specific sedimentary layers. The Black Sea example highlights that dissociation and the associated methane release in the water column or even in the atmosphere could be largely delayed by overpressure accumulation. Plain Language Summary Methane hydrate is an ice-like compound composed of a cage of water molecules enclosing a methane molecule. Hydrates can form where water and methane are present under high pressure and low temperatures, for example, in deep-sea sediments. As a result of climate change (e.g., seawater temperature increase), hydrates can melt and release free gas and water. Yet we observe that hydrates are present where they should have melted according to modeling. We explain this irregular melting by differing properties of the host sediments and different quantities of hydrate in the sediments. Methane in the Earth's atmosphere is a strong greenhouse gas. The release of methane from hydrate melting has been proposed as a runaway process where the methane released increases global warming, which further increases hydrate melting and methane release, repeating the cycle. Our results show that the destabilization of a hydrate system is actually a slow process, spanning several millennia. As such, a catastrophic destabilization of a gas hydrate system is unlikely.

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Section: Discussionmentioning

confidence: 99%

Irregular BSR: Evidence of an Ongoing Reequilibrium of a Gas Hydrate System

Colin

Ker

Riboulot

et al. 2020

Geophysical Research Letters

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“…17.2-15.7 ka BP, hyperpycnal floods from the Danube River were identified as the main sediment source, and sediment deposition and burial of reactive minerals under lacustrine oxic bottom water conditions was much more rapid than modern sedimentation. The analysis of clay mineralogy and Nd isotope signatures of the Danube and its main tributaries suggested that early periods of meltwater release during 32.5-30.5 ka BP supplied smectite-poor, chlorite and dolomite-rich sediments from Eastern Alpine domains (Martinez-Lamas et al, 2020). Thereafter between 30 and 29 ka J o u r n a l P r e -p r o o f…”

Section: J O U R N a L P R E -P R O O Fmentioning

confidence: 99%

“…The Danube River is considered to be the major source of sediment to the north-western margin of the Black Sea (Lericolais et al, 2013), especially during the ca. 32-17 ka period (Martinez-Lamas et al, 2020). Over this period, the river was characterized by high flood activity supplying huge amounts of sediment to the margin and the deep basin.…”

Section: Introductionmentioning

confidence: 99%

“…Over this period, the river was characterized by high flood activity supplying huge amounts of sediment to the margin and the deep basin. Martinez-Lamas et al (2020) demonstrated that the major sources of sediment have changed over that period, primarily because of the dynamics of the Alpine Ice sheets (AIS), but also that of the Fennoscandian Ice Sheet (FIS) (Soulet et al, 2013). Changes in the chemical composition and mineralogy of the deposited sediment are controlled by the relative inputs from the Danube tributaries connected to three main zones of the drainage basin (Martinez-Lamas et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

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Effects of postglacial seawater intrusion on sediment geochemical characteristics in the Romanian sector of the Black Sea

Ruffine

Deusner

Haeckel

et al. 2021

Marine and Petroleum Geology

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Pore water and sediment geochemistry in the western Black Sea were investigated on long Calypso piston core samples. Using this type of coring device facilitates the recovery of the thick sediment record necessary to analyze transport-reaction processes in response to the postglacial sea-level rise and intrusion of Mediterranean salt water 9 ka ago, and thus, to better characterize key biogeochemical processes and process changes in response to the shift from lacustrine to marine bottom water composition. Complementary data indicate that organic matter degradation occurs in the upper 15 m of the sediment column. However, sulfate reduction coupled with Anaerobic Methane Oxidation (AOM) is the dominant electron-accepting process and characterized by a shallow Sulfate Methane Transition Zone (SMTZ). Net silica dissolution, total alkalinity (TA) maxima and carbonate peaks are found at shallow depths. Pore water profiles clearly show the uptake of K+, Mg2+ and Na + by, and release of Ca2+ and Sr2+ from the heterogeneous lacustrine sediments, which is likely controlled by chemical reactions of silicate minerals and changes in clay mineral composition. Iron (Fe2+) and manganese (Mn2+) maxima largely coincide with Ca2+ peaks and suggest a close link between Fe2+, Mn2+ and Ca2+ release. We hypothesize that the Fe2+ maxima below the SMTZ result from deep Fe3+ reduction linked to organic matter degradation, either driven by DOC escaping from the shallow sulfate reduction zone or slow degradation of recalcitrant POC. The chemical analysis of dissolved and solid iron species indicates that iron is essentially associated with clay minerals, which suggests that microbial iron reduction is influenced by clay mineral composition and bioavailability of clay mineral-bound Fe(III). Overall, our study suggests that postglacial seawater intrusion plays a major role in shaping redox zonation and geochemical profiles in the lacustrine sediments of the Late Quaternary.Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site. Highlights► Geochemical analyses highlight multiple diagenesis processes occurring in the sediment. ► Intense methane seepages and organic matter degradation contribute to the sulfate reduction. ► Chemical of dissolved and mineral iron species indicate that iron is associated with clay minerals. ► In response to seawater intrusion, ion exchange, dissolution and reverse weathering reactions change the composition of clay constituting the sediment.

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“…If this change in strength arose from altered density of outflowing Mediterranean Water, in a manner similar to velocity minima during sapropels, this would require a large freshwater discharge into the Mediterranean during H1.1. In principle, this could have come from the Fennoscandian ice sheets via the Caspian‐Black Sea corridor (Bahr et al, 2005; Denton et al, 1999; Major et al, 2002, 2006; Martinez‐Lamas et al, 2020; Ryan et al, 2003; Soulet et al, 2013; Tudryn et al, 2016) or from the Alps (Braakhekke et al, 2020; Monegato et al, 2017; Ravazzi et al, 2014; Tombo et al, 2015). However, within radiocarbon dating uncertainties, the timing and pattern of freshwater discharge to the Mediterranean reported by these authors does not fit with the MOW weakening events observed in this study.…”

Section: Impact Of Surface and Intermediate Water Circulation On The mentioning

confidence: 99%

Mediterranean Overflow Over the Last 250 kyr: Freshwater Forcing From the Tropics to the Ice Sheets

Sierro

Hodell

Andersen

et al. 2020

Paleoceanog and Paleoclimatol

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To investigate past changes in the Mediterranean Overflow Water (MOW) to the Atlantic, we analyzed the strength of the MOW and benthic δ 13 C along the last 250 kyr at Integrated Ocean Drilling Program (IODP) Site U1389 in the Gulf of Cadiz, near the Strait of Gibraltar. Both the strength of the MOW and the benthic δ 13 C were mainly driven by precession-controlled fluctuations in the Mediterranean hydrologic budget. Reduced/enhanced Nile discharge and lower/higher Mediterranean annual rainfall at precession maxima/minima resulted in higher/lower MOW strengths at Gibraltar and stronger/weaker Mediterranean overturning circulation. At millennial scale, the higher heat and freshwater loss to the atmosphere during Greenland stadials increased buoyancy loss in the eastern Mediterranean. This enhanced the density gradient with Atlantic water, resulting in a higher MOW velocity in the Gulf of Cadiz. Unlike non-Heinrich stadials, a lower-amplitude increase in velocity was seen during Heinrich stadials (HSs), and a significant drop in velocity was recorded in the middle phase. This weak MOW was especially recognized in Termination I and II during HS1 and HS11. These lower velocities at the depth of Site U1389 were triggered by MOW deepening due to the lower densities of Atlantic intermediate water caused by freshwater released from the Laurentide and Eurasian ice sheets. The intrusion of salt and heat at deeper depths in the Atlantic during HSs and its shoaling at the end could have contributed to drive the changes in the Atlantic Meridional Overturning Circulation during Terminations.

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Linking Danube River activity to Alpine Ice-Sheet fluctuations during the last glacial (ca. 33–17 ka BP): Insights into the continental signature of Heinrich Stadials

Abstract: Please note that this is an author-produced PDF of an article accepted for publication following peer review. The definitive publisher-authenticated version is available on the publisher Web site.

Cited by 30 publications

References 182 publications

Irregular BSR: Evidence of an Ongoing Reequilibrium of a Gas Hydrate System

Irregular BSR: Evidence of an Ongoing Reequilibrium of a Gas Hydrate System

Effects of postglacial seawater intrusion on sediment geochemical characteristics in the Romanian sector of the Black Sea

Mediterranean Overflow Over the Last 250 kyr: Freshwater Forcing From the Tropics to the Ice Sheets

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