Coconino Cross Bedding - EPOD - a service of USRA
2003年3月27日 · This erosion resistant layer forms a spectacular cliff of 300-500 feet (90–150 meters) not far below the Canyon’s rim. Dating to approximately 260 million years ago, the Coconino is composed of nearly pure quartz sand. The cross-bedded features indicate that the Coconino Sandstone is basically petrified sand dunes.
Cross-bedding - Geology is the Way
Cross-bedding (or cross-stratification) is a primary sedimentary feature characterized by layers that intersect at an angle with each other through planar erosional surfaces that truncate inclined beds and laminae. This structure is the result of the migration of bedforms, such as dunes, ripples, and megaripples, produced by wind or water ...
Cross-Bedded Sandstones: Windblown or Water Carried?
2020年5月6日 · Researchers have found the same thing with the huge layers of Navaho Sandstone at Zion National Park and with the Coconino Sandstone found in the Grand Canyon. Both of these deposits cover vast areas of the United States and are usually referred to as cemented Sahara-type sand dunes.
"Cross-bed Inclinations" by John H. Whitmore
2023年12月1日 · To address this problem, cross-bed inclinations of ancient sandstones and from modern eolian dunes were collected from the literature and from some from personal field measurements. Sandstones include the Coconino, Wescogame, Tapeats, Navajo, Manakacha, Esplanade, Cedar Mesa and Botucatú.
2018年10月10日 · In earlier Skeptical Inquirer articles I described how cross-bedding with maximum angles of dip greater than 30o in the Navajo Sandstone gives evidence that this sandstone was created by wind deposition that produced giant dunes in a desert environment.
much scientific evidence that the Coconino Sandstone has an eolian desert origin whereas young-Earth creationists insist that it is water-deposited by Noah’s flood. Scientific evidence presented by Helble include discussions of dune cross-bedding with dip angles more than 30 degrees typical of desert dunes, raindrop prints, grain shapes,
An Analysis of Cross-Lamination the Coconino Sandstone
This paper calls atention to the advantages of the use of the stereographic polar net for representation of cross-bed attitudes and describes a mode of analysis for the same based on the consideration of each attitude as a vector quantity.
(PDF) Characterization of hard‐to‐differentiate dune stratification ...
2021年1月1日 · To interpret depositional processes in the Coconino Sandstone, cross‐bed facies were characterized using a suite of sedimentary textures and structures.
estimate the water depth and current speed associated with deposition of cross-bedded sandstones during a global Flood is examined. It is shown how this graphical pro-cedure was used to estimate a widely quoted depth and speed of Flood waters said to be responsible for depositing the Coconino Sandstone and other Grand Canyon
CC365.1: Coconino Sandstone deposition environment.
2003年6月23日 · The Coconino Sandstone, the origin of which is conventionally attributed to desert sand dunes, was deposited by water. Evidence for this (in addition to the character of fossil footprints therein) includes cross-bedding angles of only 25 degrees, not the 30-34 degrees one expects from desert dunes.