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|Title:||Airborne resistivity and magnetometer survey in northern Maine for obtaining information on bedrock geology|
|Authors:||United States. Army. Corps of Engineers. New England Division.|
Sellmann, P. V. (Paul V.)
Arcone, Steven A.
Delaney, Allan J.
|Publisher:||Cold Regions Research and Engineering Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
|Series/Report no.:||CRREL report ; 76-37.|
Abstract: Geophysical studies were conducted during September and October of 1975 in northern Maine to locate rock types suitable for construction purposes for the proposed Dickey-Lincoln School Dam Project. Simultaneous airborne magnetometer and VLF electrical resistivity surveys were performed over an area of approximately 920 km^2 surrounding the confluence of the St. John and Allagash rivers. The resulting data were used to construct contour maps of apparent resistivity and of total magnetic intensity above the earth's background magnetic field. During the same time period, ground and multi-elevation surveys were performed over a special test sector of known geology. The ground and airborne study in the test sector aided in interpretation of the data by revealing a strong correlation between igneous geology, resistivity, and magnetic intensity. Lack of a similar correlation between resistivity and magnetic data in the remainder of the survey area suggested an absence of additional areas of igneous rocks. The multi-elevation survey of the test area indicated that changes in flight altitude, necessitated by the topographic relief encountered, would not seriously affect the regional resistivity patterns. Although there was no strong evidence of igneous rocks outside the test sector, suitable rock types may exist within the Dss geologic unit (cyclically bedded gray slate and sandstone) in the central part of the main survey area, where most of the high resistivity contours occur.
|Rights:||Approved for public release; distribution is unlimited.|
|Appears in Collections:||CRREL Report|