Characterizing the Spiritwood Valley Aquifer using Helicopter Time-Domain Electromagnetics

Monday, December 4, 2017: 11:10 a.m.
101 D (Music City Center)
Jean Legault , Geotech Ltd., Aurora, ON, Canada
Timothy Eadie , Geotech Ltd., Aurora, ON, Canada
Geoffrey Plastow , Geotech Ltd., Aurora, ON, Canada
Alexander Prikhokdo, Dr. , Geotech Ltd., Aurora, ON, Canada
David Hisz , Water Appropriations, North Dakota State Water Commission, Bismarck, ND
Jon C. Patch, P.E. , Water Appropriations, North Dakota State Water Commission, Bismarck, ND

Buried valley aquifers, consisting of permeable sand and gravel deposits in eroded bedrock valleys, are important sources of groundwater supply in many regions of the United States and Canada. Buried valley aquifers have been difficult to define because they are often partially eroded, have complex lithology and are hidden by other shallow sand and gravel aquifers within thick glacial overburden. One example of a buried valley aquifer is the Spiritwood system that is an important supply of water both in the US and Canada.

Investigations of the Spiritwood aquifer in southern Manitoba by the Geological Survey of Canada and other workers, have demonstrated the value of helicopter time domain electromagnetic (TDEM) surveys in aquifer mapping and characterization using the contrasts between Quaternary glacio-lacustrine sand-gravels (high resistivity) that are relatively permeable and clay-tills (low resistivity) that are relatively impermeable, as well as the deeper, much less resistive Cretaceous Pierre Formation Shale basement rocks. This success provided the impetus for the North Dakota State Water Commission to fly a VTEM helicopter EM survey in the Jamestown, ND region in October, 2016.

The VTEM data collected over the Spiritwood-JT block allowed for geological mapping from near surface to depth, in spite of relatively weak resistivity contrasts (<10X). These data were inverted with a layered-earth algorithm to produce resistivity-depth models. These models were able to resolve the location and depths to the top and bottom of the Spiritwood aquifer throughout the central portion of the block providing more detailed pictures of the aquifer’s geometry. In addition to resolving the main aquifer as well as its deeper channels, the VTEM data and models highlighted several smaller, previously undiscovered aquifers that cross-cut/branch-off from the main Spiritwood channel. These are interpreted as probable transverse low-K barriers that were apparent from the existing test drilling and aquifer testing.

Jean Legault, Geotech Ltd., Aurora, ON, Canada
Jean M. Legault is a +30 year career exploration geophysicist. He obtained his Bachelor’s degree in applied science (geophysics) at Queen’s University at Kingston, ON and his Master’s degree in applied science (geophysics) at École Polytechnique of University of Montreal, QC. He is an experienced geophysicist in both the ground and airborne geophysics sectors since 1985. He is chief geophysicist at Geotech Ltd. (Aurora), a worldwide airborne geophysical service provider, where he is mainly interested in passive and active-source airborne EM methods as geological mapping tools for mineral exploration and groundwater. Jean has authored and co-authored over 50 papers and journals articles, and has been a regular speaker at geophysical conferences around the world over the last 10 years. He is a past president of KEGS, co-chair of the SEG Mining Committee, a director of the KEGS Foundation, and a member of SEG, ASEG, EAGE, as well as APEO, APGO and OGQ.


Timothy Eadie, Geotech Ltd., Aurora, ON, Canada
Graduated with B.Sc. from York University, Toronto, Ontario.


Geoffrey Plastow, Geotech Ltd., Aurora, ON, Canada
Graduated with BSc from Carleton University, Ottawa,Canada


Alexander Prikhokdo, Dr., Geotech Ltd., Aurora, ON, Canada
Bachelor’s degree in Computer Sciences and Programming, Pacific State Polytechnic University, Russia. Master’s degree in Geophysics, National Mining University, Ukraine Ph.D., Postgraduate in Institute of Geophysics of Academy of Science. Ekaterinburg, Russia


David Hisz, Water Appropriations, North Dakota State Water Commission, Bismarck, ND
David is a hydrologist in the Water Appropriations division of the North Dakota State Water Commission, in Bismarck, ND.


Jon C. Patch, P.E., Water Appropriations, North Dakota State Water Commission, Bismarck, ND
Jon C. Patch is the Director of the Water Appropriations Division, of the North Dakota State Water Commission, in Bismarck, ND.


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