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We report the discovery of concentrated invertebrate inchnofossils in close association with a dinosaur nest from the Hekou Formation in Jiangxi Province, China. The seven dinosaurian eggs reported clearly belong to the Elongatoolithidae and burrow traces were most likely made by small crustaceans. This association prompts the question as to whether invertebrate activity had relations with the buried eggs. This may be just an occasional case or the eggs may have organically increased the content of organic matter in soil which attracted the crustaceans.
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Bones displaying evidence of modification by macro, meso and microorganisms occur frequently in the ?Albian - early Cenomanian Cretaceous Kem Kem Group of the Tafilalt in southeast Morocco. Excluding the traces caused by other vertebrates (bite marks, tooth punctures, scratch marks, trample fractures) the different types of modification identified include a variety of borings referable to the ichnogenera Cubiculum, Cuniculichnus, Osteichnus and Osteocallis. Although the identity of the borers cannot always be confirmed several are attributed to dermestid beetles, possibly mayflies of the family Polymitarcidae, and perhaps to the activity of plant roots or fungal hyphae. Microbial damage to Kem Kem Group bones appears to be minimal.
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Digambar A. Ovhal, Bandana Samant, N.S. Dhoble, D.M. Mohabey & S.J. Dhoble (2020)
Thermoluminescence study in fossils of dinosaur bones and eggshells.
Luminescence (advance online publication)
doi:
https://doi.org/10.1002/bio.3892https://onlinelibrary.wiley.com/doi/10.1002/bio.3892In this paper thermoluminescence (TL) characterization of fossils of sauropod dinosaur bone, dinosaur eggshells and associated sediments are recorded for the first time. The fossil bone was collected from the Bagwanya intertrappean sediments in Dhar district of Madhya Pradesh. TL was recorded followed by 60Co gamma rays exposure at different doses. Fossils of dinosaur bone, dinosaur eggshells and associated sediments were irradiated by 60Co gamma rays with different doses from 0.15 kGy to 19 kGy. The linear dose response curve of irradiated sample was obtained for dose range from 0.15 kGy to 9.5 kGy. These geological samples were further characterized by XRD for the confirmation of phase, scanning electron microscope (SEM), FTâIR and WDâXRF for the determination of elemental composition for ppm to percentage level.
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Tore G. Klausen, Niall W. Paterson & Michael J. Benton (2020)
Geological control on dinosaursâ rise to dominance: Late Triassic ecosystem stress by relative sea level change.
Terra Nova (advance online publication)
doi:
https://doi.org/10.1111/ter.12480https://onlinelibrary.wiley.com/doi/10.1111/ter.12480
The Late Triassic is enigmatic in terms of how terrestrial life evolved: it was the time when new groups arose, such as dinosaurs, lizards, crocodiles and mammals. Also, it witnessed a prolonged period of extinctions, distinguishing it from other great mass extinction events, while the gradual rise of the dinosaurs during the Carnian to Norian remains unexplained. Here we show that key extinctions during the early Norian might have been triggered by major seaâlevel changes across the largest delta plain in Earthâs history situated in the Triassic Boreal Ocean, northern Pangea. Fossil and rock records display extensive marine inundations with floral turnover, demonstrating how susceptible widespread lowâgradient delta plains were to transgressions. Landward shoreline translocation implies decrease of important coastal regions and ecological stress on the dominant Archosauria, thriving in these habitats, and we argue that these unique geological factors played an important role in dinosaurs gradual rise to dominance.
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Lars B. Clemmensen, Dennis V. Kent, Malte Mau, OctÃvio Mateus & Jesper MilÃn (2020)
Triassic lithostratigraphy of the Jameson Land Basin (central East Greenland), with emphasis on the new Fleming Fjord Group.
Bulletin of the Geological Society of Denmark 68: 95-132
doi:
https://doi.org./10.37570/bgsd-2020-68-05
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https://2dgf.dk/xpdf/bull68-95-132.pdfThe lithostratigraphy of the Triassic deposits of the Jameson Land Basin in central East Greenland is revised. The new Scoresby Land Supergroup is now composed of the Wordie Creek, Pingo Dal, Gipsdalen and Fleming Fjord Groups. This paper only deals with the lithostratigraphy of the late Early-Late Triassic continental deposits of the latter three groups with emphasis on the vertebratebearing Fleming Fjord Group. The new Pingo Dal Group consists of three new formations, the RÃdstaken, Paradigmabjerg and Klitdal Formations (all elevated from members), the new Gipsdalen Group consists of three new formations, the Kolledalen, Solfaldsdal (with the new GrÃklint Member) and Kap Seaforth Formations (all elevated from members), and the new Fleming Fjord Group is subdivided into three new formations, the Edderfugledal, Malmros Klint and Ãrsted Dal Formations (all elevated from members). The Edderfugledal Formation contains two cyclic bedded, lacustrine members, a lowermost Sporfjeld Member (elevated from beds), and an uppermost Pingel Dal Member (elevated from beds). The lacustrine red beds of the Malmros Klint Formation are not subdivided. The lacustrine and fluvial Ãrsted Dal Formation contains three new members. In the eastern and central part of the basin, the formation is initiated by cyclic bedded, red lacustrine mudstones of the Carlsberg Fjord Member (elevated from beds), while in the northwestern part of the basin the lowermost part of the formation is composed of grey fluvial conglomerates and sandstones with subordinate red mudstones of the Bjergkronerne Member (elevated from beds). The uppermost part of the formations in most of the basin is composed of cyclic bedded, variegated lacustrine mudstones and grey to yellowish marlstones of the Tait Bjerg Member (elevated from beds). The sediments in the Fleming Fjord Group contain remains of a rich and diverse vertebrate fauna including dinosaurs, amphibians, turtles, aeotosaurs, pterosaurs, phytosaurs and mammaliaforms. Most vertebrate bones have been found in uppermost Malmros Klint Formation, and in the Carlsberg Fjord and Tait Bjerg Members. The Norianâearly Rhaetian, lacustrine Fleming Fjord Group was deposited at about 41Â N on the northern part of the supercontinent Pangaea. Lacustrine sedimentation was controlled by seasonal as well as longer-term (orbital) variation in precipitation. Precipitation was probably brought to the basin by southwesterly winds. The lacustrine sediments of the uppermost Fleming Fjord Group show deposition during increasingly humid conditions changing the lake environment from an ephemeral lake-steppe area to a perennial lake. This evolution of lake environment suggests a change from a winter-wet temperate climate to one with precipitation throughout the year.
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