Microvertebrates from the Rhaetian basal bone bed of Saltford,near Bath,SW England     

Matthieu Moreau  Christopher J. Duffin  Claudia Hildebrandt  Deborah Hutchinson  Adam Parker  Simon Carpenter  Michael J. Benton 《Proceedings of the Geologists' Association. Geologists' Association》2021,132(2):174-187

The famous Rhaetian bone bed (Late Triassic, 205 Ma) is well known because it marks a major switch in depositional environment from terrestrial red beds to fully marine conditions throughout the UK and much of Europe. The bone bed is generally cemented and less than 10 cm thick. However, we report here an unusual case from Saltford, near Bath, S.W. England where the bone bed is unconsolidated and up to nearly 1 m thick. The exposure of the basal beds of the Westbury Formation, Penarth Group includes a bone bed containing a diverse Rhaetian marine microvertebrate fauna dominated by sharks, actinopterygian fishes and reptiles. Despite the unusual sedimentary character of the bone bed, we find similar proportions of taxa as in other basal Rhaetian bone beds (55–59 % Lissodus teeth, 13–16 % Rhomphaiodon teeth, 12–14 % Severnichthys teeth, 6–9% Gyrolepis teeth, 3–4% undetermined sharks’ teeth, 1–3% undetermined bony fish teeth, and < 1% of each of Hybodus, Parascylloides, and Sargodon), the only differences being in the proportions of Rhomphaiodon teeth, which can represent 30–40 % of specimens elsewhere. This suggests that taphonomic bias of varying Rhaetian bone beds may be comparable despite different sedimentary settings, and that the proportions of taxa say something about their original proportions in the ecosystem.  相似文献   

Partly obscured accretion disc model to explain shifted broad Balmer emission lines of active galactic nuclei     

Xue-Guang Zhang  Deborah Dultzin  Ting-Gui Wang  Guinevere Kauffmann 《Monthly notices of the Royal Astronomical Society》2009,397(3):1510-1520

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Analysis and simulated diagenesis of kerogen in a Recent bottom mud from Mono Lake,California: a comparison with selected ancient kerogens     

Deborah S. Sklarew 《Geochimica et cosmochimica acta》1979,43(12):1949-1958

The insoluble organic matter, or kerogen, in a Recent bottom mud (<1000yr old) from Mono Lake, California, has been analyzed by vacuum pyrolysis-GC-MS and compared with the kerogen from several Precambrian rocks, including the Belingwe and Transvaal stromatolites. The Mono Lake kerogen consists mainly of cyclic and acyclic aliphatic components with lesser amounts of aromatics present. It is less aromatic and more susceptible to thermal degradation than the Precambrian kerogens, and its products show a much greater diversity especially among the unsaturated aliphatics and the heteroatomic components. The presence of these compounds, most notably 2,5-dimethylfuran, in the Mono Lake kerogen indicates a relatively rapid formation and incorporation into a young kerogen and suggests that their presence in the Precambrian kerogens, such as the Belingwe stromatolite, may be consistent with an ancient biological origin.In simulated diagenesis experiments the Recent mud was heated at 150°C for 3 months or 225°C for 8 months. The former was insufficient to affect the kerogen pyrolysis products. The latter, however, caused a large decrease in the heteroatomic components and a slight increase in the abundance of n-alkanes relative to that of the cyclic and branched alkanes. This suggests that the presence of some of these components in Precambrian rocks should be consistent with a high degree of preservation of these rocks, as appears to be the case for the Belingwe and Transvaal stromatolites.  相似文献   

Capitalism, masculinity and whiteness in the dialectical landscape: The case of Tarzan and the Tycoon     

Deborah Dixon  John Grimes 《GeoJournal》2004,59(4):265-275

The intent of this paper is to explore how ‘reel’ and ‘real’ landscapes can be rendered dialectic. The analysis focuses on the filming of Tarzan's Secret Treasure (1941) at the wildlife preserve of Wakulla Springs in Florida, which was administered by the financial tycoon Ed Ball. Using Mitchell's recent commentaries on ‘good’ and ‘bad’ dialectics as our entry point, we offer two readings of this cinematic process. The first renders the on and off screen Wakulla Springs as ideological fodder, serving to valorise capital, masculinity and whiteness. The second reading addresses how this place has been actively constructed from discourses pertaining to class, gender and race, such that Wakulla exists as a series of fully relational spaces within diverse contexts, both ‘real’ and ‘reel’. In structuring our analysis in this manner, we hope to make clear why it does indeed matter for film geographers to acknowledge the conceptual presumptions brought to bear in the framing of the real and the reel as objects of analysis. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

A Regionally Based Energy End‐Use Strategy: Case Studies from Centre County,Pennsylvania*     

Deborah Feder 《The Professional geographer》2004,56(2):185-200

The production and use of fossil fuels and nonrenewable electricity creates many forms of environmental degradation. To reduce degradation, this research suggests an energy strategy based on energy end‐use analysis and regional geography. Energy end‐use analysis and regional geography are used to match renewable energy resources with site‐specific, end‐use needs. Fieldwork conducted within Centre County, Pennsylvania, demonstrates that small‐scale solar, wind, and micro‐hydropower resources could displace a proportion of household electricity use. Such an approach meets energy end‐use needs, while conserving fossil fuels and reducing environmental degradation.  相似文献   

The Consumer Society and the Postmodern City by David B Clarke     

Deborah Leslie 《Area》2006,38(2):221-222

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Using logistic regression to merge mineral resource databases     

Deborah J. Shields  Stella W. Todd 《Natural Resources Research》1998,7(1):53-61

The purpose of this project was to develop and test a methodology for determining the likelihood that mineral resource location records from two nationwide mineral resource information databases represent the same site. The long-term goal is to create a comprehensive database by merging the Mineral Resource Data System (MRDS) of the U.S. Geological Survey, and the Mineral Availability System/Mineral Industry Location System (MAS/MILS) of the U.S. Bureau of Mines (now part of the Geological Survey). Part of that process involves linking records for the same site from each database. Match probabilities were estimated using a logistic regression of mineral resource location attributes, derived from known matched (cross-referenced) and known unmatched randomly sampled mineral site pairs from within the conterminous United States (n=10,000). Model accuracy was assessed using a randomly sampled test dataset, not used in logistic model development (n=4,000). Probability distributions were similar between the development and test datasets. The overall agreement beyond chance was good for the test data set using the kappa statistic. Classification accuracy was 89.6% for known matched site pairs and 84.0% for known unmatched site pairs based on a probability threshold of 0.50 for a match. Distributions of attributes were similar between the development and test datasets. This classification method is a viable approach for estimating match probabilities between database records.  相似文献   

A natural resource damage assessment model for coastal and marine environments     

Thomas A. Grigalunas  James J. Opaluch  Deborah French  Mark Reed  Dean Knauss 《GeoJournal》1988,16(3):315-321

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A literary geography of Soweto     

Deborah Hart 《GeoJournal》1986,12(2):191-195

Humanist inspired literary geography offers one avenue of enquiry into the study of place. Its prime intention is to untangle the subjective, personalised construction and connotations of place meaning. African literature offers a rich source of information into the black urban experience. The presentation focuses upon the literary interpretation of Soweto, South Africa's largest black township. The Sowetan environment emerges as a landscape of placelessness in which the overwhelming emphasis by white and black writers alike is upon relating appalling conditions in an austere and hostile environment.  相似文献   

Evolution of the modern Nile delta promontories: development of accretional features during shoreline retreat   总被引：1，自引：0，他引：1  

Omran Frihy  Deborah Lawrence 《Environmental Geology》2004,46(6-7):914-931

The active accretional features that have developed along the modern Nile Delta promontories during shoreline retreat are analysed using topographic maps, remote imagery, ground and hydrographic surveys, together providing 15 time-slice maps (1922–2000) at Rosetta and 14 time-slice maps (1909–2000) at Damietta. Small double sandy spits developed and persisted at Rosetta between 1986 and 1991. At Damietta, a much larger single spit, 9 km long, formed approximately east of the mouth of the Damietta Nile branch between 1955 and 1972, although its source has now been depleted. Both the Rosetta and Damietta inlets are associated with submerged mouth bars that accumulated prior to the damming of the Nile, but that continue to contribute to local sedimentation problems, particularly at Rosetta. The development of the active accretional features along the Nile promontories reflects a combination of factors including sediment availability, transport pathways from source areas, a decrease in the magnitude of Nile flood discharges, as well as the impact of protective structures at the river mouths.  相似文献