72 research outputs found

    Agate Fossil Beds National Monument, Paleontological Resources Management Plan (Public Version)

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    Executive Summary Since Agate Springs Ranch was founded by James H. Cook in 1887, exquisite examples of transitional Miocene mammalian fauna have been found along this stretch of the Niobrara River valley. Collectively these paleontological discoveries, along with the existing archeological and historical Native American collection, were the basis for establishing Agate Fossil Beds National Monument (AGFO) as a unit of the National Park System (NPS). The fossil remains from the Harrison and Anderson Ranch formations span a short, but important, time period within the Miocene Epoch. AGFO has provided science with an intimate look into North American mammalian evolution of the time that is matched nowhere else, with body fossils and trace fossils (burrows) of many mammals in excellent condition. Investigation of the paleontological resources at AGFO has been very limited since its establishment, but the opportunities for research and discovery are still substantial. Public and academic interest in the Monument’s paleontological resources are considerable. Although there are existing legal authorities, policies and guidelines regarding the management of paleontological resources, at both the departmental and agency levels, more specific guidance would be helpful for the management of AGFO’s non-renewable fossils. This document has been prepared to provide more specific guidance and recommendations for paleontological resources management at AGFO. The Introduction outlines the significance of AGFO’s paleontological resources and defines the purpose, need, and objectives for the Agate Fossil Beds National Monument Paleontological Resources Management Plan (PRMP). This plan also identifies the legal authorities, requirements, and mandates underpinning AGFO’s mission as a unit of the NPS, with special attention to authorities that address managing and preserving paleontological resources. Background Geology and Paleontology provides a basic park geologic description, discusses the scope of AGFO’s paleontological resources, and summarizes past paleontological work performed at the Monument. This information includes historical information from periods both before and after authorization of the Monument as a unit of the NPS. This section also presents the paleontological significance of AGFO and its specimens, such as how AGFO’s taxa are cornerstones of North American geochronology and biostratigraphy. Paleontological Resources Management begins by listing in greater detail the strategic objectives related to paleontological resources within the NPS and at AGFO. This section then proceeds to discuss the specific considerations related to paleontological resource inventories and monitoring along with management requirements (from policy and guidelines) specific to AGFO. This section discusses what a paleontology inventory is and why, when and how to conduct one; fundamentals of paleontological resource monitoring; the various types of threats to paleontological resources and how to mitigate them; and resource condition assessment and site monitoring protocols. It also addresses how to handle paleontological resources discovered or recovered during other park activities. Paleontological Research Management presents NPS and AGFO research goals, how to evaluate the scientific significance of research, and how to weigh the significance of research against other park mandates, operations, and goals. The section also includes a description of the permitting process, recommended park-specific permit conditions, and rules for overseeing collection and excavation. Museum Collections and Curation documents AGFO’s current paleontological collections, collections management and curation policies, AGFO’s photographic archives, collections from AGFO in external repositories, type specimens from AGFO, and Monument compliance with museum security policies. Interpretation discusses goals and current implementation for how AGFO interprets its paleontological resources for the public. This includes: the primary themes for interpretation; the exhibits, tools and programs used by AGFO to interpret fossil resources; the target audiences for the interpretive programs; teaching good stewardship of paleontological resources; and a discussion of public accessibility to AGFO, its interpretive materials, and the paleontological resources. Relation of Paleontological Resources to Other Park Programs provides an overview of how each park division may interact with paleontological resources and have their duties cross over with paleontological resource management related actions. It also discusses the potential impacts of paleontological resource management on other types of AGFO resources (archeological, biological, historical, and physical). Paleontological Resource Data Management discusses various paleontological resource records, datasets, and other archives. AGFO’s paleontological archives and library, as well as their current status, are discussed along with an overview of the type of contents stored within them. The NPS Paleontology Program Archives and Library, and how to exchange data and records between them and the AGFO archives, are also described. This section also reviews geospatial data available to AGFO and issues of sensitivity and confidentially related to paleontological resource data and information. Finally, the Summary, Conclusions, and Recommendations summarizes the work done on the AGFO PRMP, discusses ongoing and planned projects which assist in implementing the instructions and goals set out in this PRMP, and makes a variety of recommendations for future paleontological resource management at AGFO

    Pleistocene/Holocene Cave Fossils From Grand Canyon National Park: Ice Age (Pleistocene) Flora, Fauna, Environments, and Climate of the Grand Canyon, Arizona

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    The Colorado Plateau is a distinct physiographic province in western North America covering an area of roughly 337,000 km2 (130,115 mi2) across parts of Arizona, Colorado, New Mexico, and Utah. Elevations range from about 360 m (1,180 ft) in the overall Grand Canyon (GC; which includes the Grand Canyon National Park, GRCA) river corridor to an average at the eastern South Rim of 2,072 m (6,800 ft) to 3,850 m (12,630 ft) on the nearby San Francisco Peaks at Flagstaff, Arizona, with an average elevation of 1,525 m (5,000 ft). The Colorado River of Grand Canyon is located along the southwestern portion of the Colorado Plateau in Arizona and is renowned for its dramatic display of geomorphic effects created by fluvial incision and its unique dry-preservation of fossils from the Ice Age (late Pleistocene and Holocene [Quaternary]; most recent 2.58 million years). Although there were at least 22 glacial-interglacial cycles during the Ice Age, this discussion is limited to the most recent episode (called the Wisconsinan Glaciation), which includes the transition to the modern climate (latest Pleistocene and Holocene; the most recent 50,000 years of geologic history)

    Local probing of the field emission stability of vertically aligned multiwalled carbon nanotubes

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    Metallic cantilever in high vacuum atomic force microscope has been used as anode for field emission experiments from densely packed vertically aligned multi-walled carbon nanotubes. The high spatial resolution provided by the scanning probe technique allowed precise setting of the tip-sample distance in the submicron region. The dimension of the probe (curvature radius below 50nm) allowed to measure current contribution from sample areas smaller than 1um^2. The study of long-term stability evidenced that on these small areas the field emission current remains stable (within 10% fluctuations) several hours (at least up to 72 hours) at current intensities between 10-5A and 10-8A. Improvement of the current stability has been observed after performing long-time Joule heating conditioning to completely remove possible adsorbates on the nanotubes.Comment: 15 pages, 7 figure

    Interpretative and predictive modelling of Joint European Torus collisionality scans

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    Transport modelling of Joint European Torus (JET) dimensionless collisionality scaling experiments in various operational scenarios is presented. Interpretative simulations at a fixed radial position are combined with predictive JETTO simulations of temperatures and densities, using the TGLF transport model. The model includes electromagnetic effects and collisions as well as □(→┬E ) X □(→┬B ) shear in Miller geometry. Focus is on particle transport and the role of the neutral beam injection (NBI) particle source for the density peaking. The experimental 3-point collisionality scans include L-mode, and H-mode (D and H and higher beta D plasma) plasmas in a total of 12 discharges. Experimental results presented in (Tala et al 2017 44th EPS Conf.) indicate that for the H-mode scans, the NBI particle source plays an important role for the density peaking, whereas for the L-mode scan, the influence of the particle source is small. In general, both the interpretative and predictive transport simulations support the experimental conclusions on the role of the NBI particle source for the 12 JET discharges

    Preserving fossils in the national parks: A history

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    The fossil record preserved throughout the National Park Service spans more than a billion years and is documented in at least 267 park units. The discovery, collection, study, and resource management of fossils from localities which are currently within parks sometimes predate the establishment of the National Park Service and many of the parks. Public education and interpretation at parks such as Agate Fossil Beds and Tule Springs Fossil Beds national monuments and many other designated areas include information on the rich history of paleontological field work by notable paleontologists undertaken prior to the areas being preserved as national park areas. Another important historical aspect for several dozen parks involves the conservation efforts undertaken by the public and interest groups to preserve and protect these important fossil localities. The evolution of the science and methodologies in paleontology is reflected in the resource management undertaken by the National Park Service and documented in park resource management records and archives, scientific publications, and agency policy. Today the National Park Service celebrates fossils by coordinating the National Fossil Day partnership which helps to promote the scientific and educational value of fossils
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