Giant Lake Geneva tsunami in AD 563

Kremer, Katrina; Simpson, Guy; Girardclos, Stéphanie

doi:10.1038/ngeo1618

Cited by 90 publications

(91 citation statements)

References 6 publications

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“…He proposed that a prominent channel on the lake floor was formed by sediment deposition from underwater flows generated by sinking river water (Forel, 1895; and see Girardclos et al, 2012). The relative importance of hyperpycnal river discharge, or other processes such as delta-front slope failure, for triggering turbidity currents remains a key question for this contribution.…”

Section: Introductionmentioning

confidence: 99%

How are subaqueous sediment density flows triggered, what is their internal structure and how does it evolve? Direct observations from monitoring of active flows

Talling

Paull

Piper

2013

Earth-Science Reviews

210

184

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Subaqueous sediment density flows are one of the volumetrically most important processes for moving sediment across our planet, and form the largest sediment accumulations on Earth (submarine fans). They are also arguably the most sparely monitored major sediment transport processes on our planet. Significant advances have been made in documenting their timing and triggers, especially within submarine canyons and delta-fronts, and freshwater lakes and reservoirs, but the sediment concentration of flows that run out beyond the continental slope has never been measured directly. This limited amount of monitoring data contrasts sharply with other major types of sediment flow, such as river systems, and ensure that understanding submarine sediment density flows remains a major challenge for Earth science. The available monitoring data define a series of flow types whose character and deposits differ significantly. Large (N 100 km 3 ) failures on the continental slope can generate fast-moving (up to 19 m/s) flows that reach the deep ocean, and deposit thick layers of sand across submarine fans. Even small volume (0.008 km 3 ) canyon head failures can sometimes generate channelised flows that travel at N 5 m/s for several hundred kilometres. A single event off SE Taiwan shows that river floods can generate powerful flows that reach the deep ocean, in this case triggered by failure of recently deposited sediment in the canyon head. Direct monitoring evidence of powerful oceanic flows produced by plunging hyperpycnal flood water is lacking, although this process has produced shorter and weaker oceanic flows. Numerous flows can occur each year on river-fed delta fronts, where they can generate up-slope migrating crescentic bedforms. These flows tend to occur during the flood season, but are not necessarily associated with individual flood discharge peaks, suggesting that they are often triggered by delta-front slope failures. Powerful flows occur several times each year in canyons fed by sand from the shelf, associated with strong wave action. These flows can also generate up-slope migrating crescentic bedforms that most likely originate due to retrogressive breaching associated with a dense near-bed layer of sediment. Expanded dilute flows that are supercritical and fully turbulent are also triggered by wave action in canyons. Sediment density flows in lakes and reservoirs generated by plunging river flood water have been monitored in much greater detail. They are typically very dilute (b 0.01 vol.% sediment) and travel at b 50 cm/s, and are prone to generating interflows within the density stratified freshwater. A key objective for future work is to develop measurement techniques for seeing through overlying dilute clouds of sediment, to determine whether dense near-bed layers are present. There is also a need to combine monitoring of flows with detailed analyses of flow deposits, in order to understand how flows are recorded in the rock record. Finally, a source-to-sink approach is needed because the character of subm...

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Section: Introductionmentioning

confidence: 99%

How are subaqueous sediment density flows triggered, what is their internal structure and how does it evolve? Direct observations from monitoring of active flows

Talling

Paull

Piper

2013

Earth-Science Reviews

210

184

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“…MTDs are also linked to some of the most important near-seafloor geohazards such as submerged slope failures with large tsunamigenic potential (e.g. Kremer et al, 2012). Thus, determining their triggers, emplacement, morphology and extent is crucial for deep-water hydrocarbon exploration as well as for geohazard assessments.…”

Section: Introductionmentioning

confidence: 99%

The role of mass-transport deposits and turbidites in shaping modern lacustrine deepwater channels

Corella

Loizeau

Kremer

et al. 2016

Marine and Petroleum Geology

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a b s t r a c tSubaquatic canyons are an important pathway for sediment transport into oceanic and lacustrine basins. Understanding the mechanisms governing their geomorphological evolution is a key to predict the sediment distribution patterns through these sediment conduits as well as to implement geo-hazard assessments. Submerged channels developed in large lacustrine basins offer a small-scale natural laboratory to understand the sedimentological processes operating in submarine channels. For this reason, a multidisciplinary research initiative -including time-lapse, high-resolution bathymetric surveys, innovative coring using submersibles, in situ geotechnical tests, and geophysical and sedimentological analyses-was applied to unravel the factors controlling the geomorphological evolution of the Rhone delta channels in Lake Geneva during the last decades. The morphology of the lacustrine Rhone Delta consists of a freshwater delta system deeply incised by nine canyons (C1eC9). Geotechnical measurements in proximal areas and sediment cores retrieved in the distal fans at the end of each canyon revealed complex sediment dynamics. No turbidity current events have occurred in the easternmost canyons (C1eC4) during the last decades while the western canyons sediment record (C5eC9) indicated repeated flushing events during the 20 th century. The main "active" canyon C8 has been dominated by turbidite activity on the canyon floor with frequent overspill events along the levees. A large 6.2 Â 10 6 m 3 Mass-Transport Deposit (MTD) that resembles a debrite in its upper section was found in the distal area of the active channel. The MTD was dated at 1998e2000 CE and most likely originated from proximal delta areas affected by frequent slope failures of the steep channel walls. In situ geotechnical tests on the modern proximal channel floor showed an unconsolidated soft top-layer that might have served as a low-friction surface favouring the MTD long run-out distance to the distal part of the channel. The MTD has had a major effect morphological evolution of the distal channel by filling the existing conduit, indirectly promoting the formation of a new channel. The role of MTD emplacement in subaquatic channels has important implications for hydrocarbon exploration as they control channel avulsion processes and the location of sand-prone deposits. This study gives a detailed insight on poorly investigated short-term sedimentological dynamics that affect the long-term evolution of turbidite systems and channel migration processes. This detailed model of a river-dominated deep-lacustrine depositional system can be used as an analog for similar modern and ancient deep-water systems.

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“…Investigaciones efectuadas en los lagos Ginebra (Kremer et al, 2012) y Brienz (Girardclos et al, 2007), en Suiza, muestran la importancia del estudio de estos procesos particularmente en los ambientes deltaicos, donde las elevadas pendientes y las altas tasas de sedimentación favorecen la movilización del sustrato. En ambos trabajos se hallaron evidencias de depósitos de remoción en masa (turbiditas) en la porción más profunda de los lechos lacustres, generados a partir del colapso de deltas.…”

Section: Introductionunclassified

Análisis de deslizamientos subacuáticos en deltas lacustres (lago Nahuel Huapi, Argentina) a partir de batimetrías de alta resolución

Beigt

Villarosa

Gómez

2014

CIG

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Giant Lake Geneva tsunami in AD 563

Cited by 90 publications

References 6 publications

How are subaqueous sediment density flows triggered, what is their internal structure and how does it evolve? Direct observations from monitoring of active flows

How are subaqueous sediment density flows triggered, what is their internal structure and how does it evolve? Direct observations from monitoring of active flows

The role of mass-transport deposits and turbidites in shaping modern lacustrine deepwater channels

Análisis de deslizamientos subacuáticos en deltas lacustres (lago Nahuel Huapi, Argentina) a partir de batimetrías de alta resolución

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