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J. S. Duval

Publications and source records attributed to J. S. Duval.

At least 19 recordsLinked to original sources
USGS2006

Geochemistry of bed and suspended sediment in the Mississippi river system: Provenance versus weathering and winnowing

Stream-bed sediment for the size fraction less than 150 μm, examined in 14,000 samples collected mostly from minor tributaries to the major rivers throughout the Mississippi River drainage system, is composed of 5 mineral fractions identified by factor analysis—Al-silicate minerals, quartz, calcite and dolomite, heavy minerals, and an Fe–Mn fraction. The Al-silicate fraction parallels its distribution in the regolith, emphasizing the local sediment source as a primary control to its distribution. Quartz and the heavy-mineral fraction, and associated trace elements, exhibit a complementary distribution to that of the Al-silicate fraction, with a level of enrichment in the bed sediment that is achieved through winnowing and sorting. The carbonate fraction has a distribution suggesting its dissolution during transport. Trace elements partitioned onto the Fe–Mn, possibly amorphous oxyhydride, fraction are introduced to the streams, in part, through human activity. Except for the heavy-mineral fraction, these fractions are identified in suspended sediment from the Mississippi River itself. Although comparison of the tributary bed sediment with the riverine suspended sediment is problematic, the geochemistry of the suspended sediment seems to corroborate the interpretation of the geochemistry of the bed sediment.

Arkansas basin, Ohio basin Tennessee basin, Lower ↗
USGS2000

Preliminary report on geophysics of the Verde River headwaters region, Arizona

This report summarizes the acquisition, data processing, and preliminary interpretation of a high-resolution aeromagnetic and radiometric survey near the confluence of the Big and Little Chino basins in the headwaters of the Verde River, Arizona. The goal of the aeromagnetic study is to improve understanding of the geologic framework as it affects groundwater flow, particularly in relation to the occurrence of springs in the upper Verde River headwaters region. Radiometric data were also collected to map surficial rocks and soils, thus aiding geologic mapping of the basin fill. Additional gravity data were collected to enhance existing coverage. Both aeromagnetic and gravity data indicate a large gradient along the Big Chino fault, a fault with Quaternary movement. Filtered aeromagnetic data show other possible faults within the basin fill and areas where volcanic rocks are shallowly buried. Gravity lows associated with Big Chino and Williamson Valleys indicate potentially significant accumulations of low-density basin fill. The absence of a gravity low associated with Little Chino Valley indicates that high-density rocks are shallow. The radiometric maps show higher radioactivity associated with the Tertiary latites and with the sediments derived from them. The surficial materials on the eastern side of the Big Chino Valley are significantly lower in radioactivity and reflect the materials derived from the limestone and basalt east of the valley. The dividing line between the low radioactivity materials to the east and the higher radioactiviy materials to the west coincides approximately with the major drainage system of the valley, locally known as Big Chino Wash. This feature is remarkably straight and is approximately parallel to the Big Chino Fault. The uranium map shows large areas with concentrations greater than 5 ppm eU, and we expect that these areas will have a significantly higher risk potential for indoor radon.

Arizona↗
USGS1996

Factors affecting tritium and 14carbon distributions in the unsaturated zone near the low-level radioactive-waste burial site south of Beatty, Nevada

Interpretations of the distributions of tritiated water vapor (HTO V ) and 14 carbon dioxide gas ( 14 CO 2 ) concentrations in the unsaturated zone adjacent to the low-level radioactive-waste burial site south of Beatty, Nevada, suggest that observed concentrations of 14 CO 2 could be explained by either diffusive or advective transport of the radioactive gas from the site. The distribution of HTO V cannot be explained by vapor transport, either by diffusive or advective mechanisms. Thus, liquid transport appears to have played a role in moving HTO V to well UZB-2. Although the process by which this occurred cannot be determined from available data (and indeed may never be known), it is likely that liquid wastes disposed directly into the trenches during the period from 1962 to 1975 contributed to the offsite contamination. Liquid transport may have been enhanced by precipitation and runoff into open trenches that resulted in the occasional accumulation of ponded water in the trenches and flow along preferential pathways in the underlying unsaturated zone

Nevada↗