Journal ArticleDOI
A Tsunami Deposit at the Cretaceous-Tertiary Boundary in Texas
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At sites near the Brazos River, Texas, an iridium anomaly and the paleontologic Cretaceous-Tertiary boundary directly overlie a sandstone bed in which coarse-grained sandstone with large clasts of mudstone and reworked carbonate nodules grades upward to wave ripple-laminated, very fine grained sandstones.Abstract:
At sites near the Brazos River, Texas, an iridium anomaly and the paleontologic Cretaceous-Tertiary boundary directly overlie a sandstone bed in which coarse-grained sandstone with large clasts of mudstone and reworked carbonate nodules grades upward to wave ripple-laminated, very fine grained sandstone. This bed is the only sandstone bed in a sequence of uppermost Cretaceous to lowermost Paleocene mudstone that records about 1 million years of quiet water deposition in midshelf to outer shelf depths. Conditions for depositing such a sandstone layer at these depths are most consistent with the occurrence of a tsunami about 50 to 100 meters high. The most likely source for such a tsunami at the Cretaceous-Tertiary boundary is a bolidewater impact.read more
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Tsunami: The Underrated Hazard
TL;DR: In this paper, Tsunami as a known hazard is discussed and the causes of tsunami are discussed. But the authors do not discuss the risk and avoidance of tsunami in the coastal landscape.
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Environmental Perturbations Caused by the Impacts of Asteroids and Comets
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Tsunami deposits in the geological record
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A record of Appalachian denudation in postrift Mesozoic and Cenozoic sedimentary deposits of the U.S. Middle Atlantic continental margin
C. Wylie Poag,William D. Sevon +1 more
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The palaeoclimatology, palaeoecology and palaeoenvironmental analysis of mass extinction events
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References
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Journal ArticleDOI
Chronology of fluctuating sea levels since the triassic.
TL;DR: An effort has been made to develop a realistic and accurate time scale and widely applicablechronostratigraphy and to integrate depositional sequences documented in public domain outcrop sections from various basins with this chronostratigraphic framework.
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Calculations of the Critical Shear Stress for Motion of Uniform and Heterogeneous Sediments
TL;DR: In this article, an expression for the critical shear stress of noncohesive sediment is derived from the balance of forces on individual particles at the surface of a bed, where the initial motion problem for mixed grain sizes additionally depends on the relative protrusion of the grains into the flow and the particle angle of repose.
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Wave-formed structures and paleoenvironmental reconstruction
TL;DR: Greenwood et al. as discussed by the authors proposed a plot of water depth versus wave height (h--H diagram) for showing the combination of wave parameters and water depths capable of generating any particular structure in sand of a given grain size.