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 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 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 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 Depositional Environments and Taphonomy of Vertebrate Sites in the Upper Cretaceous Tropic Shale Southern Utah written by Kaitlin A. McCormick and published by . This book was released on 2006 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Indian Mesozoic Chronicle written by Jai Krishna and published by Springer. This book was released on 2017-03-11 with total page 748 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book reviews and summarizes the Indian Mesozoic geological evolution in an innovative alternative perspective of sequence stratigraphy. It mainly focuses on the Jurassic interval, but also concisely discusses the preceding Triassic and Cretaceous geological records. The key to the study is primarily held in the recently developed ammonoid based high resolution scales in the Triassic and Jurassic period. The Indian Jurassic record is thus elevated to a high resolution pedestal. The large intra-Jurassic stratigraphic gap in Kachchh, with increase in duration from margin to basin, has been précised in different sections, along with radical revision of its long held interpretation from sub-aerial to sub-marine all over from Arabia to Australia. Other significant gaps are also differentiated into sub-aerial and sub-marine. The Indian Late Precambrian – Neogene record is organized into five mega-sequences. Among these, the fourth – also the most important one – includes the intra-Permian to Early Eocene interval from the origin to the closure of the Neotethys. Based on multidisciplinary integration of the Indian Mesozoic geological record and comparison with hydrocarbon producing basins on east and west of India, a highly positive scenario of the hydrocarbon source/reservoir sediment perspective is outlined in the book in sequence stratigraphic backdrop as an edifice for future elaborate evaluation.
Download or read book Bonebeds written by Raymond R. Rogers and published by University of Chicago Press. This book was released on 2010-02-15 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: The vertebrate fossil record extends back more than 500 million years, and bonebeds—localized concentrations of the skeletal remains of vertebrate animals—help unlock the secrets of this long history. Often spectacularly preserved, bonebeds—both modern and ancient—can reveal more about life histories, ecological associations, and preservation patterns than any single skeleton or bone. For this reason, bonebeds are frequently studied by paleobiologists, geologists, and archeologists seeking to piece together the vertebrate record. Thirteen respected researchers combine their experiences in Bonebeds, providing readers with workable definitions, theoretical frameworks, and a compendium of modern techniques in bonebed data collection and analysis. By addressing the historical, theoretical, and practical aspects of bonebed research, this edited volume—the first of its kind—provides the background and methods that students and professionals need to explore and understand these fantastic records of ancient life and death.
Download or read book A Taphonomic Study of Selected Sites in the Poison Strip Sandstone and Ruby Ranch Members of the Cedar Mountain Formation Lower Cretaceous East Central Utah written by David A. Lee and published by . This book was released on 2014 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: Taphonomic characteristics were explored and described in order to understand the relationship between preservation of vertebrate fossils and corresponding lithostratigraphic units in the upper Cedar Mountain Formation of east-central Utah. This was accomplished through collection, analysis, and interpretation of taphonomic data collected from fossil specimens and their corresponding stratigraphic units from two localities: Tonys Bone Bed (Poison Strip Sandstone Member) and Lorries Site (Ruby Ranch Member). In addition to original quarry descriptions and assemblage information, taphonomic data were collected, including weathering and abrasion, which were compared by locality and element shape in order to determine their relationship. Data regarding fracturing and breakage were also collected and analyzed in order to better understand the post-depositional conditions of bone degradation. Both localities were described and characterized by weathering traits, abrasion traits, degree of articulation, preferred long bone orientation, and corresponding lithofacies. Tonys Bone Bed is characterized by less prominent degrees of weathering and differential transport abrasion by element shape, as well as preferred long-bone orientation, and corresponds to a lake margin debris flow and pedogenically altered overbank deposit. Lorries Site is characterized by more pronounced weathering, which is differentiated based on element shape, prominent long-bone orientation, and corresponds to a crevasse splay deposit with carbonate concretionary development.
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 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 Current Topics on Taphonomy and Fossilization written by Miquel de Renzi and published by . This book was released on 2002 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vertebrate Taphonomy and Paleoecology of a Cretaceous Paleogene Marine Bonebed written by Zachary M. Boles and published by . This book was released on 2016 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this dissertation, I characterize the vertebrate taphonomy and paleoecology of the Cretaceous-Paleogene Main Fossiliferous Layer (MFL) of the Hornerstown Formation, exposed at the Rowan Fossil Quarry in Mantua Township, New Jersey. The MFL has been proposed to represent a: 1) reworked deposit; 2) time-averaged deposit; or 3) a mass-death assemblage, possibly related to the K/Pg impact event. If the mass-death scenario is correct, the MFL would represent the only known vertebrate bonebed located stratigraphically at the K/Pg Boundary and would offer unique insight into the immediate aftermath of the bolide impact event. In spite of the potential importance of this site, no systematic taphonomic studies had been conducted prior to my research. Beginning in 2012, the MFL was systematically excavated and all contextual information was recorded. Several associated and articulated partial skeletons were recovered from an area of ~ 150 m2 in addition to hundreds of isolated bones. A "bloat and float" scenario can explain the abundance of isolated skeletal elements. Preservation of skeletal elements varies, although abrasion is typically minor or absent. Bioerosion is relatively common and may account for much of the damage to the bones. My taphonomic data, when viewed in light of other previous studies, favors the hypothesis that the MFL formed over a relatively short period of time due to a sudden influx of vertebrate carcasses. I also report the first recovery of soft-tissue-like structures from marine vertebrate fossils with known handling history and negative controls. Osteocyte-like structures were isolated from turtle shell elements of various taxa as well as from an indeterminate turtle humerus. Osteocyte- and vessel-like structures were also isolated from the femur of a marine crocodile, Thoracosaurus neocesariensis. However, not all of the sampled bone samples yielded soft-tissue-like structures. At least within the MFL, preservation of these microstructures is independent of taxon, skeletal element, or the macroscopic preservation of the bone. Instead, the best indicator of both the preservation of microstructures and bone microstructure is the fossil color. In the sampled bone fragments, tan colored samples yielded no or poorly preserved osteocyte-like structures whereas darker colored samples provided abundant and/or well-preserved cell-like structures. This study indicates that soft-tissue-like structures can be preserved in a marine setting and that they can be recovered from sediments completely waterlogged over geologic time. My third chapter focuses on the preservation and identification of vertebrate coprolites in the MFL. At least 178 coprolites were recovered from the MFL and at least seven morphotypes are recognized based on size, morphology, and the presence of inclusions. Heteropolar spiral coprolites are abundant and were likely produced by chondrichthyans with a spiral valve. Pellets, small cylindrical coprolites and large cylindrical coprolites may have been produced by bony fish, sea turtles, crocodilians, and/or mosasaurs. None of these morphotypes, except for the single large heteropolar spiral coprolite and a few indeterminate coprolite fragments, possess identifiable inclusions. Instead, most visible inclusions are small brown or black structures that may represent highly digested bone fragments. The phosphatic nature of the coprolites and the presence of some bone material suggest that carnivores likely produced many of them. However, the specific producer(s) cannot be identified. Complete coprolites are uncommon with most exhibiting some degree of pre-fossilization damage including breaks and bioerosion (e.g. coprophagy). For my final chapter, I described the shell bone histology of six of the eight turtle taxa known from the MFL. Based on the histology, overall architecture, and compactness of the bones, I was able to infer the habitat preference of the turtles. Agomphus pectoralis and Adocus beatus likely inhabited freshwater habitats near the shore, whereas Bothremys barberi and Taphrosphys sulcatus were shallow marine sea turtles. The bone histology of Peritresius ornatus suggests a shallow marine environment whereas the compactness values and overall shell morphology suggest a more pelagic lifestyle. Catapleura repanda is suggested to be a pelagic turtle based on bone histology, bone compactness values, and overall shell morphology.
Download or read book Depositional environment and taphonomy of some fossil vertebrate occurrences in Lower Permian redbeds in Archer County Texas written by Dr. Martin Sander and published by . This book was released on 1984 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Lower Permian Admiral Formation redbeds in north-central Texas are famous for their well-studied vertebrate fauna. Taphonomical and paleoecological aspects, however, are inadequately understood. The prerequisite for taphonomical interpretations is an analysis of the depositional environments. Low relief and low regional dip expose extensive paleoslopes in western Archer County. Three major depositional systems may be recognized: a fine-grained meanderbelt, a low sinuosity fine-grained fluvial system, and a tidal flat. The small scale of the sedimentation (average sandstone thickness 1. 5 m) is remarkable. Four types of vertebrate occurrences can be distinguished: Type 1: Mass death bonebeds are situated in a floodbasin facies comprised of gray and red mudstones with abundant Psaronius roots (a swamp-dwelling tree fern) which is associated with the fluvial systems. Such basins were covered by a dense swamp forest with a high diversity of vertebrates. This type is exemplified by the Geraldine Bonebed, which has yielded at least 45 partly articulated skeletons representing 4 genera of tetrapods, and remains of another 8 vertebrate taxa. The bones were found on a layer of fern, seed fern, and conifer foliage and wood. This occurrence was formed by a single catastrophic event, possibly a forest fire, which drove the animals of the swamp forest into a pond, where they died of suffocation and were concentrated into a bonebed by physical processes (wind). Type 2: Lag bonebeds, situated on the landward margin of tidal flat environments, are represented by the Rattlesnake Canyon Bonebed which consists mainly of a calcareous concretion conglomerate, which contains fragmentary bone, serpulid worm colonies (brackish water!), and calamitelean wood. The diversity of forms represented by articulated material is low. The ubiquitous predator Dimetrodon and an amphibian, Trimerorachis, which tolerates brackish water, are common. This type was deposited as lag in a storm washover deposit. Type 3: Ponds (abandoned channels, etc.) which contained a fauna dominated by aquatic forms (the fishes Xenacanthus and Ectosteorachis, and the amphibian Archeria) were gradually filled by fine-grained sediment and organic debris (vertebrates, plants). These oxbow lakes were probably rimmed by stands of Calamites. Four examples are described. Type 4: Single, complete skeletons examplified here by Diadectes are occasionally found in red floodplain mudstones.
Download or read book Biosphere to Lithosphere written by International Council for Archaeozoology. Conference and published by Oxbow Books Limited. This book was released on 2005 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: Some taphonomic investigations on reindeer (Rangifer tarandus groenlandicus) in West Greenland / Kerstin Pasda -- Magnitude of faunal accumulations by carnivores and humans in the South American Andes / Mariana Mondini -- Anthropogenic versus non-anthropogenic bird bone assemblages : new criteria for their distinction / Véronique Laroulandie -- Owls, diurnal raptors, and humans : signatures on avian bones / Zbigniew Bochenski -- Predator bias and fluctuating prey populations / Jim Williams -- Taphonomic consequences of the use of bones as fuel : experimental data and archaeological applications / Sandrine Costamagno [and others] -- Taphonomic influences on cremation burial deposits : implications for interpretation / Fay Worley -- Microfossils in camelid dung : taphonomic considerations for the archaeological study of agriculture and pastoralism / M. Alejandra Korstanje -- Why ancient DNA research needs taphonomy / Eva-Maria Geigl -- Bone density variation between similar animals and density variation in early life : implications for future taphonomic analysis / Robert Symmons -- Contribution to knowledge of the Pleistocene mammal-bearing deposits of the territory of Siracusa (southeastern Sicily) / Corrado Marziano and Salvatore Chilardi -- Using comparative micromammal taphonomy to test palaeoecological hypotheses : ʻUbeidiya, a Lower Pleistocene site in the Jordan Valley, Israel, as a case study / Miriam Belmaker -- Fragments of information : preliminary taphonomic results from the middle Palaeolithic breccia layers of Misliya Cave, Mount Carmel, Israel / Guy Bar-Oz [and others] -- Bone weathering and food procurement strategies : assessing the reliability of our behavioural inferences / Nellie Phoca-Cosmetatou -- Social changes in the early European Neolithic : a taphonomy perspective / Arkadiusz Marciniak.
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 Sequence Stratigraphy and Vertebrate Taphonomy of the Upper Cretaceous Two Medicine and Judith River Formations Montana written by Raymond R. Rogers and published by . This book was released on 1995 with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Depositional Environment and Diagenetic Effects on Sand Bodies Within the Unconventional Resource Play of the Spearfish Formation triassic in North Central North Dakota written by Matthew Joseph Sebade and published by . This book was released on 2014 with total page 262 pages. Available in PDF, EPUB and Kindle. Book excerpt:
