Dinne Mesa SW, preliminary geologic map of part of the Carrizo Moutains area, northeastern Arizona
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A study was performed by the U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, to describe the geohydrology and distribution of light-nonaqueousphase liquids in an industrialized area of northwestern Indiana and northeastern Illinois. The geologic units of concern underlying this area are the carbonates of the Niagaran Series, the Detroit River and Traverse Formations; the Antrim Shale; and sands, silts, and clays of Quaternary age. The hydrologic units of concern are surface water, the Calumet aquifer, the confining unit, and the Silurian-Devonian aquifer. Water levels collected in June 1992 indicate that the water-table configuration generally is a subdued reflection of topography. Recharge from landfill leachate and ponded water, discharge to sewers, and pumping also affect the water-table configuration. A depression in the potentiometric surface of the Silurian-Devonian aquifer results from pumping. Light-nonaqueous-phase liquids were detected near petroleum handling, industrial and waste-disposal facilities. Horizontal ground-water velocity at the water table in the confining unit ranged from 4.4x10 -4 to 1.0x10 -3 feet per day. Horizontal ground-water velocity in the Calumet and Silurian-Devonian aquifers ranged from 1.0x10 -2 to 3.4x10 -1 and from 1.4x10 -2 to 2.9x10 -2 feet per day, respectively. Vertical hydraulic gradients indicate generally downward flow from the Calumet aquifer into the confining unit, then into the Silurian-Devonian aquifer. Calculated vertical groundwater velocity through the weathered and unweathered parts of the confining unit are 3.8x10 -2 and 1.5x10 -3 feet per day, respectively.
The U.S. Geological Survey, in cooperation with the Tennessee State Planning Office, conducted a 4 l/2-year water-quality study in the Clinch and Powell River drainage basins in northeastern Tennessee. An intermittent sampling program was conducted from June 1989 through January 1994. Water-quality samples were collected and analyzed for an upstream site and a downstream site on each river. The upstream sites were near the Tennessee-Virginia State line, and the downstream sites were located on the rivers upstream of Norris Lake. At the upstream sites, fecal coliform bacteria exceeded the water-quality criteria for recreational use in 14 of 40 samples. At the downstream sites, counts exceeded the criteria limits in 2 out of 22 samples. Concentrations of nitrogen and phosphorus compounds were within the range expected for natural surface water. Nutrient discharge did not correlate well to streamflow, rainfall, and seasonal effects. Suspended-sediment discharge at the four study sites was related to streamflow, a rainfall factor, and seasonal effects. Average annual sediment yields among sites were estimated at 97 tons per square mile per year on the Clinch River and 184 tons per square mile per year on the Powell River. Concentrations of calcium, magnesium, sodium, potassium, sulfate, chloride, silica, and fluoride were all measured within the range expected for a natural carbonate system. Instantaneous total-iron concentrations exceeded the U.S. Environmental Protection Agency criteria for fish and aquatic life at the upstream sites in 23 of 28 samples on the Clinch River, and in 38 of 44 samples on the Powell River. At the downstream sites, total iron exceeded the same criteria in 2 of 5 samples on the Clinch River, and in 1 of 4 samples on the Powell River.
This trip will present the preliminary results of ongoing bedrock mapping in the North Hartland and Claremont North 7.5-minute quadrangles in western New Hampshire. The trip will travel from the Lebanon pluton to just north of the Sugar River pluton (Fig. 1) with the aim of examining the lower structural levels of the Bronson Hill anticlinorium (BHA), and the nature of the boundary with the rocks of the Connecticut Valley trough (CVT). Spear and others (2002, 2003, 2008) proposed that western New Hampshire was characterized by five major faults bounding five structural levels including, from lowest to highest, the “chicken yard line”, Western New Hampshire Boundary Thrust, Skitchewaug nappe, Fall Mountain nappe, and Chesham Pond nappe. Lyons and others (1996, 1997) showed the lowest level cored by the Cornish nappe and floored by the Monroe fault. Thompson and others (1968) explained the geometry of units by folding without major thrust faults, and described the second level as the Skitchewaug nappe. This trip will focus on the two lowest levels which we have revised to call the Monroe and Skitchewaug Mountain thrust sheets. Despite decades of geologic mapping in the northeastern United States at various scales, little 1:24,000-scale (or larger scale) modern bedrock mapping has been published for the state of New Hampshire. In fact, of the New England states, New Hampshire contains the fewest published, modern bedrock geologic maps. Conversely, adjacent Vermont has a relatively high percentage of modern bedrock maps due to focused efforts to create a new state-wide bedrock geologic map over the last few decades. The new Vermont map (Ratcliffe and others, 2011) has identified considerable gaps in our knowledge of the bedrock geology in adjacent New Hampshire where published maps are, in places, more than 50 years old and at scales ranging from 1:62,500 to 1:250,000. Fundamental questions remain concerning the geology across the Connecticut River, especially in regards to the stratigraphy of the BHA and CVT, and the distribution, or even existence, of faults ranging in age from Devonian to Mesozoic (e.g., Spear and others, 2008; McWilliams and others, 2010; Walsh and others, 2010). Questions to ponder on this trip include, but are not limited to: 1) Is the Bronson Hill anticlinorium allochthonous? 2) What is the crust beneath the Bronson Hill anticlinorium? 3) Is there a “Big Staurolite nappe” as proposed by Spear and others (2002, 2003, 2008)? 4) What is the role of Taconic, Acadian, and Alleghanian orogenesis in the tectonic development of the region? Modern 1:24,000-scale mapping is the first step towards answering these questions. Mapping will be supplemented by modern geochronology and geochemistry as this project develops. We plan to share some of our provisional results during this field trip.