Date of Award
Master of Science (MS)
A magnetometer survey in respect to oil exploration is a regional reconnaissance tool and, therefore, it is customary to check an interesting magnetic anomaly with a seismograph or gravimeter. An exception to this is found in micro magnetic surveys which, because of their detailed nature 28 nature, may serve as a cheek on the other types of geophysical surveying.
The two large magnetic highs may be more areas in the basement rocks, and they may indicate structure. However, the large eastward-trending magnetic high area on the west side of the map area is quite possibly due to a regional increase in magnetic susceptibility caused by changes in lithology. The lower magnetic intensity highs and lows are more likely to reflect basement and possibly overlying sedimentary structure. These highs and lows form at least one northeasterly trend which may be an irregular basement ridge. A promising place to look for oil accumulation might then be on there lower intensity magnetic highs and lows, which may reflect both basement and the overlying sedimentary structures. (See Plate IV, envelope)
Because of the coarse sensitivity setting of the instruments used and the large magnetic interval used in contouring the map, the writer does not think that structural relief of a homogenous body is generally indicated. Rather it is believed that changes in magnetic susceptibility were mapped. Ashes previously been discussed, these changes in lithology could affect the structure of the basement and possibly the sedimentary section. The writer thinks that magnetometer surveys in North Dakota made with a sensitive instrument setting can serve a definite purpose in outlining a structural prospect if the previously discussed geological and geophysical elements are kept in mind when interpreting the work.
Haraldson, Harald C., "A geomagnetic survey of parts of Pierce, Benson, Sheridan and Wells counties" (1953). Theses and Dissertations. 123.