Download or read book Comparative Taphonomy and Paleoecological Reconstruction of Two Microvertebrate Accumulations from the Late Cretaceous Hell Creek Formation Maastrichtian Eastern Montana 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 Comparative Taphonomy and Paleoecological Reconstruction of Two Microvertebrate Accumulations from the Late Cretaceous Maastrichtian Hell Creek Formation Eastern Montana written by Laura Elizabeth Wilson and published by . This book was released on 2006 with total page 212 pages. Available in PDF, EPUB and Kindle. Book excerpt: The CM assemblage is dominated by tabular, low density elements such as cycloid scales and fish vertebrae. Dense, equidimensional elements such as teeth and ganoid fish scales dominate the JPC assemblage. Transport distances, hydraulic equivalencies of dominant skeletal elements, amount of hydraulic sorting and reworking, and degree of time-averaging varies between deposits and significantly affect taxonomic distributions. Chi-squared tests and rank order analysis results demonstrate that relative abundance of taxa can be determined for portions of the assemblages despite different taphonomic processes. Most notably, relative abundance of hydraulically equivalent skeletal elements from morphologically similar organisms can be compared regardless of accumulation in non-isotaphonomic deposits. Statistical comparisons were made among osteichthians using ganoid scales, caudates using vertebrae, ornithischians using teeth, and testudinates using shell fragments. Results show that portions of the assemblage analyzed using hydrodynamically equivalent elements are not significantly different.
Download or read book Taphonomy Geology and Paleoecology of the Sandy Site an Exceptional Assemblage in the Maastrichtian Hell Creek Formation of South Dakota written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The Sandy Site is a multispecific terrestrial deposit in the fluvial sediments of the Upper Cretaceous Hell Creek Formation. It captures a diversity of Late Cretaceous dinosaurs and other vertebrates. Over three thousand bones represent at least fifty genera of birds, pterosaurs, terrestrial and aquatic tetrapods, and fish. Ten of the eleven dinosaur families found throughout the formation have been recognized at this quarry. Detailed taphonomic observations included abrasion, bone completeness, skeletal representation. These and a number of qualitative features indicated two distinct bonesets in the assemblage. An allochthonous suite included bones of tyrannosaurs, hadrosaurs and ceratopsians, which possessed taphonomic signatures similar to exotic aquatic vertebrate specimens. Smaller, unusual dinosaurs comprised a parautochthonous group with mammals, birds, pterosaurs, and small herpetofauna. Sedimentologic data suggest a fluvial crevassing event as the most likely depositional setting. Crevasse channel deposition fits with the Sandy microstratigraphic package and structures present, the narrow time resolution, and the dual nature of the taphocoenosis. A direct cause of mortality cannot be identified, but that agent and the subsequent burial of the taphocoenosis apparently occurred in two steps. Comparison with other sites indicates that Sandy was a product of fortuitous set of repeatable events, and that similar depositional environments produce mixed assemblages with multispecific parautochthonous components. The autochthonous assemblage presents a Sandy paleofauna different from conventional reconstructions of the Hell Creek Formation. Smaller dinosaurs prevailed in this setting, in marked contrast to the dominance of a few megafaunal taxa presented in previous reconstructions. The original faunule has a size structure similar to modern mammal communities. The regional ecology may have been mosaic rather than homogeneous, where large dinosaurs lived near but s.
Download or read book Journal of Vertebrate Paleontology written by and published by . This book was released on 2006 with total page 160 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Taphonomy and a Suggested Structure of the Dinosaurian Assemblage of the Hell Creek Formation Maastrichtian Eastern Montana and Western North Dakota written by Paul D. White and published by . This book was released on 1996 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Taphonomy Geology and Paleoecology of the Sandy Site an Exceptional Assemblage in the Maastrichtian Hell Creek Formation of South Dakota written by Jeffrey Alan Bartlett and published by . This book was released on 2004 with total page 143 pages. Available in PDF, EPUB and Kindle. Book excerpt: Keywords: paleoecology, taphonomy, Maastrichtian, Cretaceous, Hell Creek Formation, South Dakota, dinosaur, Sandy Site, vertebrate, paleontology.
Download or read book Taphonomy and Sedimentology of the Mason Dinosaur Quarry Hell Creek Formation upper Cretaceous South Dakota written by Jon P. Christians and published by . This book was released on 1992 with total page 214 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Depositional Environment Asssemblage Taphonomy and Diagenesis on Vertebrate Skeletal Preservation in a Crevasse Splay Sandstone Upper Cretaceous Hell Creek Formation Eastern Montana written by Daigo Yamamura and published by . This book was released on 2013 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: Although a great deal of paleontological information is derived from analyzing fossilized skeletal remains, the fossilization process of vertebrate skeletal remains is poorly understood. Depositional environment, taphonomy and diagenesis of an assemblage of vertebrate skeletal elements from a sandstone in the Late Cretaceous Hell Creek Formation are investigated in order to decipher relations between sandstone diagenesis and skeletal element fossilization. Fieldwork included taphonomic data collection, section measurement and description as well as sample collection. The rock and fossil bone samples were analyzed by petrography, cathodoluminescence, scanning electron microscopy (SEM) and X-ray diffractometry (XRD). The depositional environment including the fossil assemblage is interpreted as a crevasse splay based on the facies association of repeating sequences of mudrock and fine sandstone overlying channel and levee deposits. Taphonomic data suggest the bones were exposed on the surface up to 15 years before burial, and the assemblage is time-averaged. Although sandstone including the fossil bones indicates physical compaction, fossil bones do not exhibit signs of compaction. Barite is an unusual authigenic mineral found in fossil bones, suggesting collagen degradation during early diagenesis facilitated unique diagenetic microenvironment within bones. Calcite and siderite cements were precipitated multiple times, suggesting alkaline pore-fluid conditions were common during diagenesis. However, oversized pores and highly altered grains indicate that porefluids were acidic during late diagenesis; acidic pore-fluid conditions are likely due to the organic acid produced by degradation of organic molecule at higher diagenetic temperatures. Fossil bone minerals are altered due to 1) early pore-fluid infiltration combined with dehydration/rehydration processes, 2) saline pore-fluid infiltration and 3) increased temperature and pressure during deeper burial. This study demonstrates that petrography, XRD and SEM/EDS together can help decipher the diagenetic history of fossilized bones. In order to maximize the information, not only the fossil bones, but surrounding rocks need to be analyzed because surrounding rocks record different sets of diagenetic processes such as calcite precipitation in the vadose zone, siderite precipitation in the phreatic zones, acidic pore-fluid condition during mesogenesis.
Download or read book Taphonomy of the Sun River Bonebed Late Cretaceous Campanian Two Medicine Formation of Montana written by Benjamin Andrew Scherzer and published by . This book was released on 2008 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the summer of 1998, a bonebed of juvenile dinosaur material was found in beds of the Two Medicine Formation along the Sun River in Teton County, Montana. Initial inspection of the "Sun River Bonebed" indicated unique dominance by juvenile remains and unusually high concentration of fossil material. Modern exposure of both the bonebed and surrounding strata allowed for a detailed taphonomic study of the assemblage. In the summer of 2004, the bonebed was excavated in a fashion that recorded depthwise taphonomic data of fossil material and surrounding sediment, and allowed for three-dimensional reconstruction of the bonebed. The lithology of the surrounding beds was documented for 120 m immediately below and 40 m immediately above the bonebed to interpret the overall depositional environment of the area. Lastly, the paleobiologic and sedimentologic interpretations made for the bonebed were compared to bonebeds of similar fauna in the Two Medicine Formation. Taphonomic attributes of the fossil material indicate a mass death assemblage of late juvenile lambeosaurines subject to post-mortem bioturbation and possible fluvial transport. A number of elements from the assemblage exhibit a rare form of taphonomic modification known as "wet rot," currently documented in only one other dinosaur bonebed. Sedimentologic and additional taphonomic data in the assemblage indicate entrainment of the vertebrate material in a cohesive debris flow and ultimate deposition in the respective flow deposit. The sedimentology of the surrounding beds indicates ultimate deposition in an ephemeral fluvial environment. The restricted age class representation of the assemblage lends credence to existing paleobiologic interpretations of hadrosaurids in the Late Cretaceous of Montana, and the Sun River Bonebed is significant in its exhibition of "wet rot" modification and in being one of a restricted number of documented debris-flow hosted vertebrate bonebeds.
Download or read book An Experimental and Field based Approach to the Taphonomy of Microvertebrate Assemblages written by Mara E. Brady and published by . This book was released on 2005 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study explores the origin of concentrations of small fossil bones and teeth preserved in (1) pond/lake and (2) active channel deposits in the Judith River Formation of Montana. Vertebrate fossils recovered from both types of assemblages are similar in shape and rounding, but channel concentrations are better sorted. In flume experiments, bone concentrations formed when an active flow was directed through sediment beds with initially dispersed bone material. The coarse bone fraction was minimally transported, while the fine fraction was winnowed to distal parts of the flume. These results suggest channel assemblages may be derived from pre-existing pond/lake assemblages.
Download or read book Advances in Fluvial Dynamics and Stratigraphy written by Paul A. Carling and published by John Wiley & Sons. This book was released on 1996-08-06 with total page 550 pages. Available in PDF, EPUB and Kindle. Book excerpt: A final chapter provides a brief view of future perspectives.
Download or read book Taphonomy of Three Monospecific Dinosaur Bone Beds in the Late Cretaceous Two Medicine Formation Northwestern Montana written by Raymond R. Rogers and published by . This book was released on 1989 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vertebrate Paleontology in Utah written by David D. Gillette and published by Utah Geological Survey. This book was released on 1999 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 52 papers in this vary in content from summaries or state-of-knowledge treatments, to detailed contributions that describe new species. Although the distinction is subtle, the title (Vertebrate Paleontology in Utah) indicates the science of paleontology in the state of Utah, rather than the even more ambitious intent if it were given the title “Vertebrate Paleontology of Utah” which would promise an encyclopedic treatment of the subject. The science of vertebrate paleontology in Utah is robust and intense. It has grown prodigiously in the past decade, and promises to continue to grow indefinitely. This research benefits everyone in the state, through Utah’s muse ums and educational institutions, which are the direct beneficiaries.
Download or read book Bone Histology of Fossil Tetrapods written by Kevin Padian and published by Univ of California Press. This book was released on 2013-03-19 with total page 298 pages. Available in PDF, EPUB and Kindle. Book excerpt: The microscopic examination of fossilized bone tissue is a sophisticated and increasingly important analytical tool for understanding the life history of ancient organisms. This book provides an essential primer and manual for using fossil bone histology to investigate the biology of extinct tetrapods. Twelve experts summarize advances in the field over the past three decades, reviewing fundamental basics of bone microanatomy and physiology. Research specimen selection, thin-section preparation, and data analysis are addressed in detail. The authors also outline methods and issues in bone growth rate calculation and chronological age determination, as well as how to examine broader questions of behavior, ecology, and evolution by studying the microstructure of bone.
Download or read book The Hell Creek Formation and the Cretaceous Tertiary Boundary in the Northern Great Plains written by Joseph Herbert Hartman and published by Geological Society of America. This book was released on 2002 with total page 530 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Taphonomy of a Late Cretaceous Mammal bearing Microvertebrate Assemblage from the Deccan Inter trappean Beds of Naskal Peninsular India 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 The Trace Fossil Record of Major Evolutionary Events written by M. Gabriela Mángano and published by Springer. This book was released on 2016-11-17 with total page 497 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume addresses major evolutionary changes that took place during the Mesozoic and the Cenozoic. These include discussions on major evolutionary radiations and ecological innovations on land and at sea, such as the Mesozoic marine revolution, the Mesozoic radiation of vertebrates, the Mesozoic lacustrine revolution, the Cenozoic radiation of mammals, the evolution of paleosol biotas, and the evolution of hominins. The roles of mass extinctions at the end of the Triassic and at the end of the Cretaceous are assessed. This volume set provides innovative reviews of the major evolutionary events in the history of life from an ichnologic perspective. Because the long temporal range of trace fossils has been commonly emphasized, biogenic structures have been traditionally overlooked in macroevolution. However, comparisons of ichnofaunas through geologic time do reveal the changing ecology of organism-substrate interactions. The use of trace fossils in evolutionary paleoecology represents a new trend that is opening a window for our understanding of major evolutionary radiations and mass extinctions. Trace fossils provide crucial evidence for the recognition of spatial and temporal patterns and processes associated with paleoecologic breakthroughs.
