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Mapping clayey till layers between glacial drift aquifers using the seismic method: An aquifer vulnerability problem

Conference · · Geological Society of America, Abstracts with Programs; (United States)
OSTI ID:6974590
; ; ;  [1]
  1. Western Michigan Univ., Kalamazoo, MI (United States). Dept. of Geology

Agricultural practices such as heavy use of chemical fertilizers and hog pasturing has led to nitrate contamination of the unconfined aquifer in the Donnell Lake area, Cass County, Michigan. In order to determine the vulnerability of the underlying aquifer to nitrate contamination, several monitoring wells were installed in the study area. Many of these wells penetrated clayey till layers which appear to be discontinuous suggesting that the lower aquifer may be semi-confined and, therefore, vulnerable to nitrate contamination. As part of an ongoing hydrogeologic investigation, seismic surveys were conducted at several sites in the Donnell Lake area in order to determine the lateral continuity of the clayey till layers and the intraglacial stratigraphy. Preliminary analysis of P-wave records suggest several reflectors within the glacial drift with the strongest reflections occurring at the drift/bedrock interface. Since S-waves are not refracted at the water table, the refractions seen on S-wave records are correlated with the clayey till layers. At many of the sites, the depths to these layers determined from refraction analysis are in good agreement with driller logs and gamma-ray logs of nearby monitoring wells.

OSTI ID:
6974590
Report Number(s):
CONF-9404217--
Journal Information:
Geological Society of America, Abstracts with Programs; (United States), Journal Name: Geological Society of America, Abstracts with Programs; (United States) Vol. 26:5; ISSN GAAPBC; ISSN 0016-7592
Country of Publication:
United States
Language:
English