Download or read book New stratigraphic subdivision depositional environment and age estimate for the Upper Cretaceous Djadokhta Formation southern Ulan Nur Basin Mongolia written by Demberelyin Dashzeveg and published by . This book was released on 2005 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Stratigraphic Subdivision Depositional Environment and Age Estimate for the Upper Cretaceous Djadokhta Formation Southern Ulan Nur Basin Mongolia American Museum Novitates written by and published by . This book was released on with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book New Stratigraphic Subdivision Depositional Environment and Age Estimate for the Upper Cretaceous Djadokhta Formation Southern Ulan Nur Basin Mongolia written by Demberelyin Dashzeveg and published by . This book was released on 2005 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Studies of key and newly discovered sections of the Upper Cretaceous Djadokhta Formation along the southern margin of the Ulan Nur Basin allow a new subdivision based on lithology. The formation and its members were mapped at both Bayn Dzak, an area that includes the Flaming Cliffs, and Tugrugyin Shireh, an area about 50 km to the northwest of Bayn Dzak. Stratigraphic sections at both localities were remeasured. The considerably enlarged formation comprises a lower Bayn Dzak Member, dominated by moderate reddish orange sands with subordinate mudstone units, and an upper Tugrugyin Member, composed of pale orange to light gray sands. Investigations of key sections at Tsonzh and Alag Teer demonstrate the presence of transitional mudstone lenses between these members within the Djadokhta Formation. Two distinct, sandy, sedimentologic facies are recognized in both members. Crossbedded intervals, occasionally exhibiting wind-ripple cross lamination, document the presence of a Cretaceous dunefield in the Ulan Nur Basin. Structureless intervals are interpreted to represent wet sandy fluvial deposits and debris flows that moved down the dune faces. In the Bayn Dzak Member, lenses of brownish mudstone are interpreted to represent interdune deposition in shallow ponds by fluvial action. Fluvial action is also represented in the Bayn Dzak Member by beds of caliche, which contain conglomerate at the base but fine upward into limestone. The vertebrate fauna from the Djadokhta Formation is summarized. Although the Bayn Dzak fauna lived somewhat earlier than that from Tugrugyin Shireh based on the superposition of the members, it is not clear how much earlier. The fauna from the Djadokhta Formation has previously been assigned ages from Cenomanian to earliest Maastrichtian. New magnetostratigraphic data document a sequence of normal and reversed magnetozones through the Bayn Dzak Member up into the basal Tugrugyin Member. The presence of reversed magnetozones establishes that the sediments containing the faunas were probably deposited after C34n. The quick stratigraphic succession of normal and reversed magnetozones suggests, but does not clearly establish, that the sediments may have been deposited during the rapid sequence of polarity changes in the late part of the Campanian between about 75 to 71 Ma.
Download or read book New Perspectives on Horned Dinosaurs written by Michael J. Ryan and published by Indiana University Press. This book was released on 2010-06-22 with total page 1180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Easily distinguished by the horns and frills on their skulls, ceratopsians were one of the most successful of all dinosaurs. This volume presents a broad range of cutting-edge research on the functional biology, behavior, systematics, paleoecology, and paleogeography of the horned dinosaurs, and includes descriptions of newly identified species.
Download or read book Hadrosaurs written by David A. Eberth and published by Indiana University Press. This book was released on 2014-11-05 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive study of the Late Cretaceous, duck-billed dinosaur, featuring insights on its origins, anatomy, and more. Hadrosaurs—also known as duck-billed dinosaurs—are abundant in the fossil record. With their unique complex jaws and teeth perfectly suited to shred and chew plants, they flourished on Earth in remarkable diversity during the Late Cretaceous. So ubiquitous are their remains that we have learned more about dinosaurian paleobiology and paleoecology from hadrosaurs than we have from any other group. In recent years, hadrosaurs have been in the spotlight. Researchers around the world have been studying new specimens and new taxa seeking to expand and clarify our knowledge of these marvelous beasts. This volume presents the results of an international symposium on hadrosaurs, sponsored by the Royal Tyrrell Museum and the Royal Ontario Museum, where scientists and students gathered to share their research and their passion for duck-billed dinosaurs. A uniquely comprehensive treatment of hadrosaurs, the book encompasses not only the well-known hadrosaurids proper, but also Hadrosaouroidea, allowing the former group to be evaluated in a broader perspective. The 36 chapters are divided into six sections—an overview, new insights into hadrosaur origins, hadrosaurid anatomy and variation, biogeography and biostratigraphy, function and growth, and preservation, tracks, and traces—followed by an afterword by Jack Horner. “Well designed, handsome and fantastically well edited (credit there to Patricia Ralrick), congratulations are deserved to the editors for pulling together a vast amount of content, and doing it well. The book contains a huge quantity of information on these dinosaurs.” —Darren Naish, co-author of Tetrapod Zoology, Scientific American “Hadrosaurs have not had the wide publicity of their flesh-eating cousins, the theropods, but this remarkable dinosaur group offers unique opportunities to explore aspects of palaeobiology such as growth and sexual dimorphism. In a comprehensive collection of papers, all the hadrosaur experts of the world present their latest work, exploring topics as diverse as taxonomy and stratigraphy, locomotion and skin colour.” —Michael Benton, University of Bristol
Download or read book Phylonyms written by Kevin de Queiroz and published by CRC Press. This book was released on 2020-04-30 with total page 995 pages. Available in PDF, EPUB and Kindle. Book excerpt: Phylonyms is an implementation of PhyloCode, which is a set of principles, rules, and recommendations governing phylogenetic nomenclature. Nearly 300 clades - lineages of organisms - are defined by reference to hypotheses of phylogenetic history rather than by taxonomic ranks and types. This volume will document the Real World uses of PhyloCode and will govern and apply to the names of clades, while species names will still be governed by traditional codes. Key Features Provides clear regulations for implementing new guidelines for naming lineages of organisms incorporates expressly evolutionary and phylogenetic principles Works with existing codes of nomenclature Eliminates the reliance on rank-based classification in favor of phylogenetic relationships Related Titles: Rieppel, O. Phylogenetic Systematics: Haeckel to Hennig (ISBN 978-1-4987-5488-0) Cantino, P. D. and de Queiroz, K. International Code of Phylogenetic Nomenclature (PhyloCode) (ISBN 978-1-138-33282-9).
Download or read book Timetrees Incorporating Fossils and Molecules 2nd edition written by Michel Laurin and published by Frontiers Media SA. This book was released on 2022-09-15 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt: Calibrating phylogenies to time is central to addressing many questions in evolutionary biology and macroevolution. The fossil record once provided our only source for establishing a timeline for evolution. However, the incompleteness of the fossil record and the non-uniformity of fossil recovery rate make it challenging to obtain precise estimates of divergence times from fossil evidence alone. Molecular dating, which combines evidence from the geological and molecular records, enables us to generate a much more complete and precise timeline of events. The molecular clock can be time-calibrated using temporal evidence from fossils and used to estimate divergence times based on the assumption that the rate of sequence evolution will be approximately constant over time and among lineages. Methodological challenges to applying this concept in practice have been to relax the assumption of constant evolutionary rates and to model the uncertainty associated with paleontological and geological calibrations. To this end, available statistical methods have become increasingly complex in order to capture key features of empirical data. These are typically applied using Bayesian inference, which provides a powerful framework for incorporating multiple sources of uncertainty. Although overall more effort has been expended in developing models of molecular sequence evolution, critical advances have also included approaches to modeling taxonomic diversification and fossilization. In particular, recent advances in birth-death process models have allowed for continuous sampling along lineages, enabling more information from the fossil record to be incorporated into dating analyses in a statistically coherent way. In addition, available dating methods can now be applied to scenarios in which no molecular data may be available, allowing for novel insights into the evolution of entirely extinct clades. Other recent innovations enable us to date divergence times among taxa that have no fossil record, including the use of gene duplication events or biogeographic evidence. Furthermore, time-calibrated trees are necessary for obtaining phylogenetic estimates of taxonomic diversification and extinction rates, which can now be jointly inferred along with lineage divergence times. These approaches offer an exciting opportunity to understand the evolution of life in deep time, although key challenges remain, especially with regards to modeling the processes of genome evolution, taxonomic diversification and fossil recovery. In this Research Topic, we focus on recent advances in methodology, outstanding challenges, and the application of molecular and paleontological dating methods to empirical case studies across the Tree of Life.
Download or read book written by and published by . This book was released on 2015 with total page 98 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Journal of Vertebrate Paleontology written by and published by . This book was released on 2009 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stratigraphy Depositional Environments and Paleogeography of Coal bearing Strata in the Upper Cretaceous Mesaverde Group Central Grand Hogback Garfield County Colorado written by Dawn J. Madden and published by . This book was released on 1989 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: New correlations of the Trout Creek Sandstone Member and adjacent sandstone members between Rifle Gap and New Castle and new paleogeographic sketches for the oscillating shorelines at the time of Exiteloceras jenneyi and Didymoceras cheyennense.
Download or read book The Geology of Ukhaa Tolgod Djadokhta Formation Upper Cretaceous Nemegt Basin Mongolia written by Lowell Dingus and published by . This book was released on 2008 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: The lithostratigrahy and sedimentology of the fossiliferous Upper Cretaceous strata exposed in the Gobi Desert of Mongolia at Ukhaa Tolgod are described and mapped on aerial photos. Topographic features are also mapped by plane table and alidade. Five lithologic and sedimentologic facies are described: E-1, distinctly cross-stratified sandstone with fine structure, interpreted to represent eolian dune deposits; E-2, vaguely bedded sandstone with cross-stratified concretionary sheets, interpreted to represent eolian dune deposits modified by diagenetic formation of slope-parallel concretionary sheets of pedogenic calcite; S, structureless sandstone lacking concretions or cross-strata, interpreted to represent sandslide deposits generated by mass wasting along the lee slopes; C, conglomerate interpreted to represent basin-margin conglomerates washed into the dune field from adjacent topographic highs; and M, mudstone and siltstone interpreted to represent interdune deposition in ephemeral ponds and lakes. Facies E-2 and S have not been reported previously. Eleven stratigraphic sections at various localities within the Ukhaa Tolgod drainage basin are documented. The exposed composite section consists of about 75 m of pale orange sandstones, greenish-brown conglomerates, and brown siltstones that are products of an arid environment. Four schematic cross sections are documented to illustrate the lateral relationships among the five facies. In the Ukhaa Tolgod area, the beds dip about 2.5° to the south, away from the nearby Gilbent Range. This structural attitude is interpreted to be related to the uplift of the Gilbent block along normal faults exposed at the base of the range. The strata at Ukhaa Tolgod are referred to the Djadokhta Formation. Similar to the classic Djadokhta exposures at Bayn Dzak, the sequence of strata reflects a mixture of facies E-1, E-2, S, and M in the lower part of the section, with prominent beds of Facies C near the top. The dune-derived sandslides of Facies S contain a rich skeletal fauna of Late Cretaceous dinosaurs, mammals, and lizards. Essentially, all the skeletal remains collected at Ukhaa Tolgod come from Facies S. Facies E-1 does contain numerous, concave-up depressions in the cross-strata interpreted as vertebrate tracks. Facies E-2 contains abundant cylindrical structures interpreted as burrows. As seen in the Bayn Dzak Member at Bayn Dzak, facies E-1, E-2, S, and M dominate the lower part of the section at Ukhaa Tolgod, with prominent beds of Facies C exposed near the top. Accordingly, the exposures at Ukhaa Tolgod are referred to the Bayn Dzak Member of the Djadokhta Formation. Classic exposures of the Barun Goyot Formation at Khulsan differ in having units of flat-bedded sandstone intercalated with beds of Facies S near the top of the section. To date, over 1,000 vertebrate skulls and skeletons have been collected from Facies S. Most are preserved as float contained in small calcareous nodules; however, some were found in situ. Many specimens represent either fairly complete skulls or skulls with articulated or associated postcranial skeletons. Based on faunal similarities between Bayn Dzak and Ukhaa Tolgod, the fauna at Ukhaa Tolgod is interpreted to reflect a Campanian age. The rich assemblage of fossils makes Ukhaa Tolgod one of the richest Late Cretaceous vertebrate fossil localities in the world, and the fossils provide unique insights into evolutionary developments of mammals, lizards, and dinosaurs, including birds, less than 10 my before the terminal Cretaceous extinction event.
Download or read book Type and Reference Sections for a New Member of the Fox Hills Formation Upper Cretaceous Maastrichtian in the Missouri Valley Region North and South Dakota written by Mark C. Klett and published by . This book was released on 1977 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Middle Cretaceous Stratigraphy on the South and East Sides of the Uinta Basin Northeastern Utah and Northwestern Colorado written by C. M. Molenaar and published by . This book was released on 1991 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Uppermost Cretaceous and Tertiary Stratigraphy of Fossil Basin Southwestern Wyoming written by Steven S. Oriel and published by . This book was released on 1970 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: New subdivisions of the 7,000-foot-thick continental Evanston, Wasatch, Green River, and Fowkes Formations facilitate understanding of sediment genesis and Wyoming thrust-belt tectonic events.
Download or read book Stratigraphy Petrography and Depositional Environment of Greenhorn Formation upper Cretaceous of Eastern Nebraska written by Nagaraja Subraya Kirumakki and published by . This book was released on 1976 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stratigraphy and Depositional Environment of the Upper Cretaceous Horsethief Formation Northwest of Augusta Montana written by Carol Jean Bibler and published by . This book was released on 1985 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Stratigraphic revision and depositional environments of the Upper Cretaceous Toreva Formation in the northern Black Mesa area Navajo and Apache counties Arizona written by Karen J. Franczyk and published by . This book was released on 1988 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:
