EBookClubs

Read Books & Download eBooks Full Online

EBookClubs

Read Books & Download eBooks Full Online

Book Age of Tephra Beds at the Ocean Point Dinosaur Locality North Slope Alaska Based on K Ar and 40Ar 3 p9 sAr Analyses

Download or read book Age of Tephra Beds at the Ocean Point Dinosaur Locality North Slope Alaska Based on K Ar and 40Ar 3 p9 sAr Analyses written by James E. Conrad and published by . This book was released on 1992 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book U S Geological Survey Bulletin

Download or read book U S Geological Survey Bulletin written by and published by . This book was released on 1992 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Book A New Tolypella from the Ocean Point Dinosaur Locality North Slope Alaska and the Late Cretaceous to Paleocene Nitelloid Charophytes

Download or read book A New Tolypella from the Ocean Point Dinosaur Locality North Slope Alaska and the Late Cretaceous to Paleocene Nitelloid Charophytes written by Monique Feist and published by . This book was released on 1991 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: A multidisciplinary approach to research studies of sedimentary rocks and their constituents and the evolution of sedimentary basins, both ancient and modern.

Book Depositional Environments of the Late Cretaceous Maastrichtian Dinosaur bearing Prince Creek Formation

Download or read book Depositional Environments of the Late Cretaceous Maastrichtian Dinosaur bearing Prince Creek Formation written by Peter Paul Flaig and published by . This book was released on 2010 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The Prince Creek Formation contains first-order meandering trunk channels, second order meandering distributary channels, third-order fixed anastomosed(?) distributary channels, crevasse splays, levees, lakes, ponds, swamps, paleosols, and ashfall deposits. Trampling by dinosaurs is common. Most deposition occurred on crevasse splay-complexes adjacent to trunk channels. Rhythmically-repeating coarse-to fine-grained couplets in inclined heterolithic stratification suggest tidal-influence in channels. Cumulative to compound soils similar to Entisols, Inceptisols, and potential acid sulfate soils formed on levees, point bars, crevasse splays, and on the margins of lakes and swamps. Frequent overbank flooding is evidenced by silt and sand dispersed throughout paleosol profiles and fluctuations with depth in several molecular ratios. Drab colors, organics, siderite, depletion coatings, and zoned peds indicate waterlogged, anoxic conditions while ferruginous and manganiferous features, insect and worm burrows, and rare illuvial clay coatings and infillings suggest drying and oxidation of some soils. Repeated wetting and drying is tied to fluctuating river discharge. Marine influence is evidenced by jarosite, pyrite, and gypsum which become increasingly common up-section near the contact with the shallow-marine Schrader Bluff Formation. Recovered biota include Peridinioid dinocysts; algae; projectates; Wodehouseia edmontonicola; pollen from lowland trees, shrubs and herbs; Bisaccates; fern and moss spores; and fungal hyphae and indicates that all strata are Early Maastrichtian and that sediments become progressively younger from measured section NKT in the south to measured section LBB in the north. 40Ar/39Ar analysis of a tuff returned an age of 69.2 ± 0.5 Ma in the Sling Point outcrop belt. World-class dinosaur bonebeds are encased in muddy overbank alluvium overlying floodplains. No concentration of bone was found in channels. Bonebeds are laterally extensive except where truncated by distributaries. At the Sling Pont, Liscomb, and Byers bonebeds alluvium encasing bone exhibits a bipartite division of flow and a massive mudstone fades containing flow-parallel plant fragments that 'float' in a mud matrix suggesting deposition by fine-grained hyperconcentrated flows. Exceptional floods driven by seasonal snowmelt in the Brooks Range increased suspended sediment concentrations, generating hyperconcentrated overbank flows that killed and buried scores of juvenile dinosaurs occupying this high-latitude coastal plain. This unique killing mechanism likely resulted from fluctuating discharge tied to seasonality brought about by the near polar latitude of northern Alaska in the Late Cretaceous"--Leaves iii-iv.