Identification of tsunami induced deposits the tsunamite problem
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Identification of Tsunami-induced deposits: the “Tsunamite Problem”. Recent Tsunamis: Historical and archeological record Paleotsunamis: geological record  Frequency and occurrence?. Geological record of paleotsunamis. “Tsunamite’’ :

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Identification of tsunami induced deposits the tsunamite problem

Identification of Tsunami-induced deposits: the “Tsunamite Problem”

  • Recent Tsunamis: Historical and archeological record Paleotsunamis: geological record  Frequency and occurrence?


Geological record of paleotsunamis Problem”

“Tsunamite’’ :

 tractive-current-reworked conglomerates (Yamazaki et al.,1989)

 sediments transported by the tsunami wave itself and tsunami-induced current deposits (Shiki and Yamazaki, 1996)

  • = Tempestites (storm-induced sediments)

  • The term tsunamite is not a self-defining expression of a single depositional process and refers to an amalgamation of issues at several levels (Shanmugan, 2006):

    • Turbidites, debris flows, seismites, etc...


Geological record of paleotsunamis Problem”

 What are the geological proxies for tsunami-induced deposits???

As a extraordinary event, a tsunami can trigger a variety of processes including turbidity currents and debris flows.

Pure Sedimentology

 Multidisciplinary approach :

- Sedimentology – Petrology – Paleontology

- Perspectives: Rock Magnetism – Geochemistry

 Function of the paleoenvironment:

- Peculiar zones such as estuary and lagoon

- Seismites in deeper water





Some Geological proxies for tsunami-induced deposits Problem”

Flat pebble conglomerate

Molaar tooth

Identifying tsunami deposits using sedimentary features (Pratt, 2002)


Some Geological proxies for tsunami-induced deposits Problem”

Identifying tsunami deposits using boulder deposits (Dawson & Stewart, 2007)

Large coral-reef fragments deposited on Pakarang Beach, near Khao Lak, Thailand, by the 26 December 2004 tsunami. The high energies needed to remove these boulders may ensure they have a higher preservation potential than other tsunami-related onshore sediments.


Some Geological proxies for tsunami-induced deposits Problem”

Identifying tsunami deposits using bivalve shell taphonomy (Donato et al.; 2007)


A new approach: rock magnetism Problem”

Magnetic

susceptibility (Abrantes et al., 2007)

Magnetic susceptibility, grain-size mean, and radiocarbon chronology along composite perfil of the Lisbon platform. Ages as calendar yr BP; magnetic susceptibility (106 SI – blue line) and mean grain-size (μm – black line)

 Spectral analysis?????


A new approach: Problem”

rock magnetism

SEM and EDS analyses

Scanning Electron Microscopy (SEM) and Energy Dispersive Spectra (EDS) of Tsunami-induced deposits in spanish coast


A new approach: Problem”

rock magnetism

SEM and EDS analyses

Scanning Electron Microscopy (SEM) and Energy Dispersive Spectra (EDS) of Tsunami-induced deposits in spanish coast


A new approach: Problem”

rock magnetism

SEM and EDS analyses

Scanning Electron Microscopy (SEM) and Energy Dispersive Spectra (EDS) of Tsunami-induced deposits in spanish coast


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