By Herbert A. Pierce, Joseph Duval, and Dave Sutphin
Open File Report 03-498
This report describes the use of ground penetrating radar time sections converted to depth sections to measure depths to surfaces from which volumes of sand and gravel are estimated. The ground penetrating radar techniques provides a noninvasive, inexpensive, and relatively quick way to characterize the three-dimensional geometry of the deposits.
Sand and gravel deposits in southern New Hampshire are a remnant of the last 250,000 years of surficial geologic processes. At least two pulses of a thick continental ice sheet covered New Hampshire grinding and breaking the underlying rocks before sorting a small percentage of the rocks into economically important sand and gravel deposits by the melt water as the last ice sheet retreated. These industrial mineral deposits are utilized throughout the northeastern corridor of the United States. The high quality and intrinsic properties of these glacially washed sands and gravels make them sought after by the construction industry. Southern New Hampshire sand and gravels are often transported by truck and rail more than 60 miles for use in various large infrastructure projects. The resource use impacts us all through buildings, bridges, and other transportation projects. Though often thought of as vast, the resource has become increasingly scarce due to depletion, anthropologic sterilization (roads, canals, railways, parks, dams, lakes, and buildings). In addition, communities and industry throughout the state are concerned about the role the sands and gravels play in recharge, filtering, and storage of New Hampshire's valuable potable groundwater resource. The large environmental and economic impact sand and gravel has upon the area underscores the need for accurate estimates of resource.
The Industrial Minerals Program directed by Team Leader Nora Foley of the Eastern Mineral Resource Team funded experiments using geophysical techniques to map and provide estimates of sand and gravel deposits. This Open-File Report provides data, images, and discusses the application of ground penetrating radar to sand and gravel deposits in southern New Hampshire. Within this study area calculations of gravel thickness can be made to provide volumetric information important to the methodology of resource analysis.
Contact: Herbert A. Pierce
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