Filters: Tags: Palaeogeography, Palaeoclimatology, Palaeoecology (X)
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This study provides a detailed pedogenic evaluation of two Upper Triassic (Late Norian through Rhaetian) stratigraphic intervals in New Mexico in order to assess the climate and ecology of the Latest Triassic, which ended in a mass extinction. The two study areas are located in north?central and east-central New Mexico and are separated by 200 km. Each section contains abundant paleosols of varying maturity with features that reflect an arid to semiarid climate. There is little pedogenic variation throughout the strata at each location, and a typical paleosol profile is about 1 m thick and has an AB?Bw?Bk?BC horizon succession. Bkm, Bss, Bssk, or Bssg horizons are present in some paleosols. Micromorphological features...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Chinle Formation,
New Mexico,
Palaeogeography, Palaeoclimatology, Palaeoecology,
Paleoclimate,
Paleosols,
Outcrops of the upper Fruitland and lower Kirtland formations (Upper Cretaceous) in the Fossil Forest area of northwestern New Mexico, USA, contain abundant organic remains. This fossil accumulation is “typical” of the late Cretaceous of the Western Interior. The vertebrate fauna is characterized by a lack of coprocoenoses or soil accumulations, few bones with evidence of carnivore damage and a paucity of small bones. Macrovertebrate remains are disarticulated and hydrodynamically sorted. Microvertebrate accumulations are all hydrodynamic in origin. Macerated plant material is common in all rocktypes. An extensive fossil forest was preserved as the result of a large flood which drowned a floodplain forest. Invertebrates...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Palaeogeography, Palaeoclimatology, Palaeoecology
The Colorado Plateau is a distinct physiographic province in western North America, which presently straddles the transition between summer-wet and summer-dry climatic regimes to the south and northwest, respectively. In addition to climate, the diversity of environments and plant communities on the Colorado Plateau has resulted from extreme topographic diversity. Desert lowlands as low as 360 m elevation are surrounded by forested plateaus, and even higher peaks greater than 3800 m elevation. This environmental diversity provides a unique opportunity to study the history of biotic communities in an arid region of North America. Although the Colorado Plateau harbours numerous potential sites, the paleoecological...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Colorado Plateau,
Palaeogeography, Palaeoclimatology, Palaeoecology,
Quaternary,
packrat middens,
paleoecology,
The paleoecological reconstruction of Pleistocene deserts along the Colorado River of western North America is attempted using data from fossil packrat middens. The Colorado River drainage is set into a physiographic context along a gradient from the hyperarid Colorado Desert to the moist high elevations on the Colorado Plateau. The Pleistocene and modern distributions of individual plant species along this corridor are compared emphasizing records from the Picacho Peak area of the Colorado Desert and the eastern Grand Canyon. In general, plant species are now distributed 700?900 m higher in elevation and 400?700 km further up-river than they were during the late Wisconsin, however, some plant species have not conformed...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Palaeogeography, Palaeoclimatology, Palaeoecology
New paleomagnetic and stable isotopic results from the northeastern margin of the greater Green River Basin (South Pass, Wyoming) provide a refined geochronological context for the Wasatchian/Bridgerian Land Mammal Age boundary and suggest the existence of large amplitude Milankovich-scale carbon and oxygen isotopic oscillations in this area during the early Eocene. Analysis of 55 paleomagnetic sites through a 310 m section of Wasatch, Green River, and Bridger Formations indicates several reversals that can be correlated to the Geomagnetic Polarity Time Scale using radiometric age constraints. This correlation places the Wasatchian/Bridgerian boundary in Chron C23r at about 52 Ma, approximately two million years...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Palaeogeography, Palaeoclimatology, Palaeoecology,
biostratigraphy,
eocene,
green river basin,
magnetostratigraphy,
In four sections in the lacustrine Eocene Green River Formation in Utah (?Lake Uinta?), fish are preserved on carbonate mudflats, along high-energy carbonate shorelines, in the littoral zone, and in deeper profundal areas. Scattered bones and scales are found throughout, dropped from disintegrating floating carcasses. Gar scales typify shallow-water deposits, partly due to habitat preference. Beach concentrations of greatly abraded bones and scales grade offshore into storm lag layers and lenses, which grade to loosely packed horizons or patches of unworn remains. Littoral fish fossils range from dropped bones to good skeletons, with much floating, lifting, and scavenging. Preservation improves away from the waterline,...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Palaeogeography, Palaeoclimatology, Palaeoecology
A taphonomic study of the Lower Cretaceous, Dalton Wells (DW) dinosaur bonebeds near Moab, Utah, provides insight into the origins, preservational biases, and paleobiological significance of one of the richest and most diverse Early Cretaceous dinosaur sites known. The bonebeds occur in a stacked succession of debris flows at the base of the Yellow Cat Member of the Cedar Mountain Formation, which was deposited in a seasonally-dry, alluvial-lacustrine setting. Although only 5% of the locality has been collected, more than 4200 bones were recovered, representing an assemblage overwhelmingly dominated by dinosaurs — with a minimum of 67 individuals that represent at least eight genera. The assemblage also includes...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Palaeogeography, Palaeoclimatology, Palaeoecology,
bonebed,
cedar mountain formation,
debris flow,
dinosaur,
In four sections in the lacustrine Eocene Green River Formation in Utah (“Lake Uinta�), fish are preserved on carbonate mudflats, along high-energy carbonate shorelines, in the littoral zone, and in deeper profundal areas. Scattered bones and scales are found throughout, dropped from disintegrating floating carcasses. Gar scales typify shallow-water deposits, partly due to habitat preference. Beach concentrations of greatly abraded bones and scales grade offshore into storm lag layers and lenses, which grade to loosely packed horizons or patches of unworn remains. Littoral fish fossils range from dropped bones to good skeletons, with much floating, lifting, and scavenging. Preservation improves away from the...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Palaeogeography, Palaeoclimatology, Palaeoecology
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