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Monday, 20 March 2006

RE: Article on paleo-Bolide porduced tsunamites/seismites

RE: Article on paleo-Bolide produced tsunamites/seismites

Paul bristolia at
Sun Mar 19 23:30:29 EST 2006

jonee (Elton) asked:

"Anyone have a link as to specifically what tsunamites
and seismites are defined as?"

There is a definition of "tsunamite" in:

Shanmugam, G., 2006, The Tsunamite Problem. Journal
of Sedimentary Research. vol. 76. DOI: 10.2110/jsr.2006.073

The above abstract stated:

"The genetic term tsunamite is used for a potpourri
of deposits formed from a wide range of processes
(overwash surges, backwash flows, oscillatory flows,
combined flows, soft-sediment deformation, slides,
slumps, debris flows, and turbidity currents) related
to tsunamis in lacustrine, coastal, shallow-marine,
and deep-marine environments."

Although they are called "Tsunami Sand Deposits", pictures
of coastal plain "tsunamites" created by the December Indian
Ocean Tsunami can be seen in:

"The December 26, 2004 Indian Ocean Tsunami: Initial
Findings on Tsunami Sand Deposits, Damage, and
Inundation in Sri Lanka" at:

and in "Tsunami deposits (figure 3: thickness of the deposits)" at:

Another coastal tsunami deposit (tsunamite) from the
1929 Grand Banks Earthquake found at Taylor's Bay on
Newfoundland's southern coast can be seen at:

A definition of "seismite" can be found in "Developing a Classification
Scheme for Seismites" by Stephen F. Greb at:

This abstract for the 2002 North-Central Section (36th) and
Southeastern Section (51st), Geological Society of America Joint
Annual Meeting stated:

"The term "seismite" is presently used for many features and
deposits of inferred seismic origin, each of which requires
varying types and amounts of data to support a seismic

One type of seismite is sediment that show disturbance /
deformation, while it was still soft, caused by the ground
shaking, which accompanies an earthquake. Some pictures
of seismites can be found in "The Late Triassic seismite
in Northern Ireland, southwest England and south Wales" at:

A related article might be:

Walkden, G., J. Parker, and S. Kelley, 2002, A Late Triassic
Impact Ejecta Layer in Southwestern Britain. Science. vol. 298,
no. 5601, pp. 2185-2188. DOI: 10.1126/science.1076249

The Entrada Sandstone contains soft sediment deformation
features, which are argued to be impact-related seismites.
This is discussed in:

Alvarez, W., E. Staley, D. O'Connor, and M. A. Chan, 1998,
Synsedimentary deformation in the Jurassic of southeastern
Utah: A case of impact shaking? Geology. vol. 26, no. 7,
pp. 579-582.

a press release can be found at:



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