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Paul F Carr - One of the best experts on this subject based on the ideXlab platform.
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elemental and mineralogical analysis of marine and coastal sediments from phra thong island thailand insights into the provenance of coastal hazard Deposits
Marine Geology, 2017Co-Authors: D T Pham, Adam D. Switzer, Chris Gouramanis, Charles Martin Rubin, Brian G Jones, Kruawun Jankaew, Paul F CarrAbstract:Abstract Sediment records left by coastal hazards (e.g. tsunami and/or Storms) may shed light on the sedimentary and hydrodynamic processes happening during such events. Modern onshore and offshore sediment samples were compared with the 2004 Indian Ocean Tsunami, three palaeotsunami and a 2007 Storm Deposit from Phra Thong Island, Thailand, to determine provenance relationships between these coastal overwash Deposits. Sedimentological and stratigraphic characteristics are generally inadequate to discriminate tsunami and Storm Deposits so a statistical approach (including cluster analysis, principal component analysis and discriminant function analysis) was used based on grain size, mineralogy and trace element geochemistry. The mineral content and trace element geochemistry are statistically inadequate to distinguish the provenance of the modern Storm and tsunami Deposits at this site, but the mean grain size can potentially discriminate these overwash Deposits. The 2007 Storm surge Deposits were most likely sourced from the onshore sediment environment whereas all four tsunami units statistically differ from each other indicating diverse sediment sources. Our statistical analyses suggest that the 2004 tsunami Deposit was mainly derived from nearshore marine sediments. The uppermost palaeotsunami Deposit was possibly derived from both onshore and nearshore materials while the lower palaeotsunami Deposits showed no clear evidence of their sediment sources. Such complexity raises questions about the origin of the sediments in the tsunami and Storm Deposits and strongly suggests that local context and palaeogeography are important aspects that cannot be ignored in tsunami provenance studies.
K D Pieper - One of the best experts on this subject based on the ideXlab platform.
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quartz thermoluminescence in a Storm Deposit and a welded beach ridge
Quaternary Science Reviews, 2001Co-Authors: W J Rink, K D PieperAbstract:Abstract We examined the natural residual thermoluminescence (NRTL) of quartz in samples collected from the surface and the subsurface of the beach on a sand spit in the Gulf of Mexico located at St. Joseph Peninsula State Park near Apalachicola Florida. The subsurface samples were collected within two berm structures that respectively, represented a hurricane Deposit and a subsequently Deposited smaller tidal berm (beach ridge) produced by wave action during a seven-week period following the Storm. Higher NRTL was found in the underwater zone of the beach surface than in the areas exposed to full daylight on the beach and in the dunes (seawater is known to strongly absorb the ultraviolet component of daylight). In each of the berms, similar variations in NRTL could confidently be correlated to primary sedimentary structures. Strong transitions in NRTL occurred at boundaries between sedimentary units. These variations were used to interpret processes of berm formation and the identity of local sources of quartz incorporated into the berms.
M Ishii - One of the best experts on this subject based on the ideXlab platform.
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sedimentary differences between the 1993 hokkaido nansei oki tsunami and the 1959 miyakojima typhoon at taisei southwestern hokkaido northern japan
Sedimentary Geology, 2000Co-Authors: Futoshi Nanayama, K Shigeno, Kenji Satake, Koichi Shimokawa, S Koitabashi, S Miyasaka, M IshiiAbstract:Abstract Tsunami Deposits differ distinctly from Storm Deposits as seen in a trench in the southwestern Hokkaido town of Taisei, which was struck by a typhoon in 1959 and a tsunami in 1993. The typhoon generated a Storm surge that crested about 6 m above ordinary high-tide levels for 1 h. The tsunami, caused by a nearby earthquake with a magnitude of 7.8, contained two main waves and was 1–3 m higher than the typhoon surge. We found Deposits from both the typhoon and the tsunami in a 3 by 9 m trench located 60 m inland from the beach. The Deposits are similar in thickness, which in both cases decrease landward from a maximum of about 50 cm. The tsunami Deposits can be divided into four layers probably correlative with landward and seaward flows from the two main tsunami waves; the flow directions are shown by gravel fabrics, and remains of knocked-down plants. The landward tsunami flow Deposited marine sand and rounded gravel, whereas the return flow Deposited a poorly sorted mixture of soil, non-marine sand, and stream gravel with plant fragments. Only the Storm Deposit shows foreset bedding. This Deposit is mostly marine sand that is better sorted than any of the tsunami layers.
D T Pham - One of the best experts on this subject based on the ideXlab platform.
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elemental and mineralogical analysis of marine and coastal sediments from phra thong island thailand insights into the provenance of coastal hazard Deposits
Marine Geology, 2017Co-Authors: D T Pham, Adam D. Switzer, Chris Gouramanis, Charles Martin Rubin, Brian G Jones, Kruawun Jankaew, Paul F CarrAbstract:Abstract Sediment records left by coastal hazards (e.g. tsunami and/or Storms) may shed light on the sedimentary and hydrodynamic processes happening during such events. Modern onshore and offshore sediment samples were compared with the 2004 Indian Ocean Tsunami, three palaeotsunami and a 2007 Storm Deposit from Phra Thong Island, Thailand, to determine provenance relationships between these coastal overwash Deposits. Sedimentological and stratigraphic characteristics are generally inadequate to discriminate tsunami and Storm Deposits so a statistical approach (including cluster analysis, principal component analysis and discriminant function analysis) was used based on grain size, mineralogy and trace element geochemistry. The mineral content and trace element geochemistry are statistically inadequate to distinguish the provenance of the modern Storm and tsunami Deposits at this site, but the mean grain size can potentially discriminate these overwash Deposits. The 2007 Storm surge Deposits were most likely sourced from the onshore sediment environment whereas all four tsunami units statistically differ from each other indicating diverse sediment sources. Our statistical analyses suggest that the 2004 tsunami Deposit was mainly derived from nearshore marine sediments. The uppermost palaeotsunami Deposit was possibly derived from both onshore and nearshore materials while the lower palaeotsunami Deposits showed no clear evidence of their sediment sources. Such complexity raises questions about the origin of the sediments in the tsunami and Storm Deposits and strongly suggests that local context and palaeogeography are important aspects that cannot be ignored in tsunami provenance studies.
Jorge Ledesmavazquez - One of the best experts on this subject based on the ideXlab platform.
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rhodolith transport and immobilization on a volcanically active rocky shore middle miocene at cabeco das laranjas on ilheu de cima madeira archipelago portugal
Palaeogeography Palaeoclimatology Palaeoecology, 2011Co-Authors: Markes E. Johnson, Carlos Marques Da Silva, Mário Cachão, Eduardo Mayoral, Ana Santos, Ana Cristina Rebelo, Gudveig B Baarli, Jorge LedesmavazquezAbstract:Abstract Extraordinary Deposits of fossil rhodoliths occur at the Cabeco das Laranjas (Portuguese~Hill of the Oranges) in a small fault block at the northwest end of Ilheu de Cima off Porto Santo in the Madeira Archipelago. Stratigraphic repetitions of densely packed rhodolith beds up to 2.6 m thick are associated with a receding rocky shoreline, and are interpreted as the result of hurricanes. The initial Storm Deposit sits unconformably on basalt and eroded basalt boulders associated with tuff and volcaniclastic breccia. Approximately 90,000 rhodoliths of Middle Miocene age (14–15 Ma) are exposed on the upper surface of the initial Deposit over a 450-m2 shelf exhumed from the hill's southeast side. Ranging in diameter from ≤ 3 cm to 20 cm, many of the rhodoliths generated by crustose coralline red algae are now iron stained and resemble a mass of oranges in gross appearance. Sea stacks and large boulders rise through the thick basal rhodolith bed to form small catchment areas that held the Deposit in place after the Storm's passage. The succeeding rhodolith Deposits are variably separated by layers with mixed carbonate and volcanic sand, pure volcanic lapilli, and volcaniclastic tephra mixed with tuff showing swaley cross-stratification. Three out of four rhodolith beds are truncated against the flank of the adjoining rocky shore. Only the youngest (fourth) rhodolith layer is fully exposed around the perimeter of the hill and can be shown to cross a basalt barrier that is traceable for 70 m in cross section as an erosional ramp dipping from 6° to 8° southeast. The entire fossil-rich sequence is capped by a basalt flow showing columnar disjunction. Based on thin-section analysis, three genera of coralline red algae are recognized in the basal rhodolith Deposit: Sporolithon, Lithothamnion, and Neogoniolithon. Associated biodiversity is low, represented by 16 kinds of marine invertebrates dominated by encrustations and borings on the rhodoliths and very few free body fossils. The Madeira region of the North Atlantic may have been susceptible to major cyclonic Storms immediately after the Middle Miocene Climate Optimum, when a northward shift of the Inter-tropical Convergence Zone was stimulated by a steeper temperature gradient in the southern hemisphere related to expansion of continental glaciers on Antarctica.