Entries in subsurface characterization (4)


Xenon Geosystems: Environmental instrumentation, monitoring and data management

Starting in 2013, Xenon Geosystems will be offering environmental instrumentation, monitoring, and data visualization services. We will provide monitoring solutions for surface water, ground water, subsurface and ambient environmental conditions. Packages will include installation, monitoring and maintainence of instrumented nodes, data visualization, and delivery of data packages via web services. 

Our services will complement our base of geological and geophysical services and broaden the range of subsurface characterization tools which we will make available to our clients.


IDEM Remediation Closure Guide [DRAFT]

The Indiana Department of Environmental Management has issued their draft of the Remediation Closure Guide (available here http://www.in.gov/idem/6683.htm). This guide is intended as a replacement of the RISC Technical Guide, and to serve as the de facto guidance document for all environmental investigations to be performed under IDEM's regulatory programs.

Of note, the guidance document explicitly requires the development of a Conceptual Site Model of its investigated sites. The CSM is to integrate hydrogeologic settings, land use, identification of contaminants and their phases, plume characterization, and possible off-site and natural sources. We applaud this approach and believe that its implementation will result in more thoughtful and efficient investigations that will be a benefit to the citizens of Indiana.



Gamma Ray Logs

Gamma ray logging is a borehole tool that can provide useful information for environmental and engineering investigations and water resource exploration. In practice, the tool is sensitive to clay content, and functions as a sand/clay log for unconsolidated sediments, or a shale log in rock sequences. The method measures natural gamma irradiation from radioactive isotopes in the sediment/rock minerals. Potassium is the most common radioisotope in surficial geologic materials in the Midwest.

It is particulary helpful for wells with poor or absent boring logs, and can be useful in lithologic correlations. The method ties well with observed lithologic profiles and can be used to help constrain earth resistivity surveys. Ned Bleuer has applied gamma logging to the analysis of glacigenic facies (Indiana Geological Survey Special Report 65).

Gamma ray logs can be obtained from in situ wells and cased boreholes. Because it detects natural gamma radiation, there is no radioactive source within the tooling, and no NRC permitting is required.


GPR imaging of ground water seepage within an earthen dam



This is one slice of a 3-D radar survey performed at an earthen dam in northeastern Indiana (click the image to enlarge). The bright areas near the center of the image indicate ground water saturation. A geotextile layer is imaged as an inclined planar surface, and breaching of ground water from the geotextile into the fill lifts is observed. This indicates failure of the textile to route seepage to the toe drain.