Re: New Guinea tsunami information.

From: Jonathan Clarke (
Date: Wed Feb 13 2002 - 15:12:20 EST

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    Thanks david, for these.

    Some other web-based tsunami references for Allen, yourself, and anyone else interested. Summary quotes also.

    Bryant, T. and Price, D. 2001. The magnitude and frequency of tsunami along the South coast of New South Wales, Australia.

    "Tsunami waves produce four general categories of depositional and erosional evidence that can be preserved in the geological record. Individual items
    within these categories are geomorphic signatures that, singly or in combination with each other, uniquely define the impact of tsunami in the coastal
    landscape. Depositional: sand laminae, sand with boulders, chaotic mixes, imbricate boulders, smear deposits, sand sheets, beach ridges, coastal
    barriers, carseland. Erosional: cavitation marks, S-forms, whirlpools and plugs, canyons, cascades and falls, roche moutonnees, toobrush shaped
    stacks, fluted headlands, keel-shaped ridges, truncated cliffs, raised platforms, ramps, headlands, eroded barrier remnants."

    Goto, K., Tajika, E., Tada, R., Iturralde-Vinent, M., Kiyokawa, S., Oji, T., Nakano, Y., Delgado, D. Garcia, C., Reinaldo R., and Matsui, T. 2001 K/T
    boundary sequence of the Peñalver Formation: the deep-sea tsunami deposit in northwestern Cuba. GSA Annual Meeting, November 5-8, 2001,

    "The Peñalver Formation in northwestern Cuba is one of the thickest (>180 m) K/T boundary deposits in the world. It is composed of a lower gravity flow
    unit and an upper homogenite unit, the latter being interpreted as a deep-sea tsunami deposit (Kastens and Cita, 1981; Takayama et al., 2000).
    According to our previous study at the type locality, the upper homogenite unit has homogeneous appearance, and neither erosional nor current
    structures are observed (Takayama et al., 2000). However, our recent study revealed slight compositional oscillations characterized by variation in
    serpentine lithic content within the upper homogenite unit, which is repeated >6 times. These oscillations are associated with variation in coarse
    fraction content within insoluble residues and are interpreted as reflecting the repeating vertical remixing and/or lateral supply of the clastic
    particles caused not by gravity flow but by tsunami repetitions, because there is no erosional and current structure. We have also found that the
    Peñalver Formation shows lateral lithological variations, over >150 km. At Santa Isabel (60 km to the west of Havana) and Matanzas (90 km to the east
    of Havana), the upper homogenite unit is much thinner compared with that of the type locality in Havana, and has erosional surface at its base. These
    differences may reflect difference in the influence of tsunamis reflecting the difference in the depositional depth at each locality. In spite of these
    lithological variations, grain composition and grain size in the upper homogenite unit are very similar throughout the studied localities. Thus, the
    upper unit of the Peñalver Formation was probably formed by rapid sedimentation from widely expanded sediment suspended cloud caused by energetic
    impact-induced tsunamis in the Caribbean basin."

    Jacobs, S. 2001. “Fossil hash:” A late Pleistocene tsunami deposit at 2nd street, San Pedro, California. Cordilleran Section - 97th Annual Meeting, and
    Pacific Section, American Association of Petroleum Geologists (April 9-11, 2001)

    "Late Pleistocene “fossil hash,” mapped by Woodring et al. (1946) as Palos Verdes Sand, rests unconformably on the wave-cut bench. We analyzed the
    sediments and fossils of the “fossil hash” bed, with particular emphasis on determining its mode of deposition. The “fossil hash” bed, approximately
    1-2 feet thick, fills irregularities on the surface of the wave-cut bench and thins in a westerly direction. This bed is overlain by a relatively thin
    orange sand with sparse foraminifers, which indicates a marine origin, and should probably be considered part of the Palos Verdes Sand. Nonmarine older
    alluvial terrace deposits overlie the marine deposits. The “fossil hash” bed contains an admixture of littoral to outer neritic (0-200 m water depth),
    including megafossils (0-27 m) and microfossils (0-200 m), with pelagic (Neogloboquadrina pachyderma) and benthic (miliolid, 0-20 m, bolivinid, 20-100
    m, and cassidulinid, 100-200 m, foraminifer) forms. This megafossil assemblage includes small and large, whole and broken shells. The sediments include
    sand and silt with some schist pebbles. The “fossil hash” bed exhibits a lack of sorting, grading, and stratification."

    Satake K., 1994. Study of Recent Tsunamis Sheds Light on Earthquakes. Eos Vol. 75, No. 1, January 4, 1994, p. 3.
    contains useful references but no description of deposits.

    Young, R. W., Bryant, E. A., and Price, D. M. 1995. The imprint of tsunami in Quaternary coastal sediments of Southeastern Australia. Bulgarian
    Geophysical Journal, 1995, v. XXI, No4, 24-32.

    "TL and 14C dating has revealed anomalous chrono-stratigraphies at two sites on the coast of southern New South Wales, Australia where Pleistocene
    sands have been driven onshore over Holocene estuarine deposits. Lack of solar bleaching of the TL component which occurs in normal swash zones, an
    identical TL age obtained from pumice incorporated in the Pleistocene deposit, and boulders scattered through the sand are indicative of tsunami
    impact. These observations prompt reassessment of the strictly uniformitarian models of barrier emplacement during the Holocene transgression both in
    eastern Australia and elsewhere in the world where tsunami are a possibility."

    Recognising tsunami deposits is not only inveresting and important for understanding sedimentary history, but vital for coastal risk assessment, hence
    the recent interest. Allen, when discussing tsunami deposits, it is vital to distinguish between shore deposits, where sediments are transported
    shoreward by the wave, and seaward deposits, where material is transported off shore by the backwash. It is also important to distinguish those
    generated by earthquakes and those by impacts. I should note that the NSW south coast sites are becoming quite well known and are shown to first year
    university students.


    bivalve wrote:

    > An abstract on identifying tsunami depsotis in the geological record can be found at
    > Dr. David Campbell
    > Old Seashells
    > 46860 Hilton Dr #1113
    > Lexington Park MD 20653 USA
    > That is Uncle Joe, taken in the masonic regalia of a Grand Exalted Periwinkle of the Mystic Order of Whelks-P.G. Wodehouse, Romance at Droigate Spa

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