35 research outputs found

    A model of the hydrothermal system at Casa Diablo in Long Valley, California, based on resistivity profiles and soil mercury analyses

    Get PDF
    A description and model of the near-surface hydrothermal system at Casa Diablo, with its implications for the larger-scale hydrothermal system of Long Valley, California, is presented. The data include resistivity profiles with penetrations to three different depth ranges, and analyses of inorganic mercury concentrations in 144 soil samples taken over a 1.3 by 1.7 km area. Analyses of the data together with the mapping of active surface hydrothermal features (fumaroles, mudpots, etc.), has revealed that the relationship between the hydrothermal system, surface hydrothermal activity, and mercury anomalies is strongly controlled by faults and topography. There are, however, more subtle factors responsible for the location of many active and anomalous zones such as fractures, zones of high permeability, and interactions between hydrothermal and cooler groundwater. In addition, the near-surface location of the upwelling from the deep hydrothermal reservoir, which supplies the geothermal power plants at Casa Diablo and the numerous hot pools in the caldera with hydrothermal water, has been detected. The data indicate that after upwelling the hydrothermal water flows eastward at shallow depth for at least 2 km and probably continues another 10 km to the east, all the way to Lake Crowley

    Areal and vertical distribution of total soil mercury and total phosphorusin the southern half of water conservation area 3-A, Everglades, Southern Florida

    Get PDF
    Total soil-mercury and phosphorus concentrations were determined in 64 sites in the southern half of Water Conservation Area 3A, an area of approximately 500 km2 . Surface soil-Hg concentrations ranged from 117 to 300 ng-g-1;total phosphorus concentrations range from 350 to 850 pg~g-1. No consistent north-south or east-west trends are found in the mercury or phosphorus surface concentrations when they are normalized to soil bulk density. Nine sites were used for the determination of the vertical distribution of soilmercury. Vertical profiles of soil-Hg revealed decreasing concentrations with depth and correlated well with phosphorus in soil profiles. Mercury concentrations in soil profiles may be interpreted as an increase in the rate of deposition of mercury in the region in recent decades and/or as postdepositionalmobilization of mercury to surface layers

    Water induced sediment levitation enhances downslope transport on Mars

    Get PDF
    On Mars, locally warm surface temperatures (~293 K) occur, leading to the possibility of (transient) liquid water on the surface. However, water exposed to the martian atmosphere will boil, and the sediment transport capacity of such unstable water is not well understood. Here, we present laboratory studies of a newly recognized transport mechanism: “levitation” of saturated sediment bodies on a cushion of vapor released by boiling. Sediment transport where this mechanism is active is about nine times greater than without this effect, reducing the amount of water required to transport comparable sediment volumes by nearly an order of magnitude. Our calculations show that the effect of levitation could persist up to ~48 times longer under reduced martian gravity. Sediment levitation must therefore be considered when evaluating the formation of recent and present-day martian mass wasting features, as much less water may be required to form such features than previously thought

    Recognizing, Determining, and Addressing Entrepreneurial Innovations By Superintendents of Emerging or Established Educational Service Agencies

    No full text
    This dissertation describes how entrepreneurial superintendents of educational service agencies (ESAs) recognize, determine and address common and distinct innovative characteristics within emerging or established regional educational environments. Because internal and external factors assist in recognizing innovative practices, this study verifies how superintendents obtain this information and reviews internal standard operating procedures. This study also explores if entrepreneurial activities can be replicated at other ESAs. The supporting roles of staff and governing board members of entrepreneurial ESAs are examined from superintendents‘ perspectives. This national study utilized an online questionnaire with 34 entrepreneurial ESA superintendents participating from 34 states and two state specific case studies from Minnesota and Pennsylvania, representing an emerging and established entity. This study concludes with summary analyses of the data, conclusions are offered, and suggestions are made for further study

    The Equatorial Deposits: Possible Glacial Remnants

    No full text

    Equatorial Ice Sheets of Mars

    No full text

    Perspective: Some Future Trends and Needs of Rural Schools and Communities

    Full text link
    corecore