Date of Award

1978

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Geology

First Advisor

F.R. Karner

Abstract

Thirty-one new heat flow determinations in North Dakota range from 0.6 to 1.9 HFU. The majority of heat flow measurements were completed for southwestern North Dakota.

Heat flow measurements were made in both oil and water wells. Heat production data from basement rocks when used in conjunction with nearby heat flow values indicate that only two of six sites may be considered to be similar to Basin and Range type of heat flow. One site occurs in southwestern North Dakota in a region west of 103° W where no heat flow value is less than 1.5 HFU. The other site is in north-central North Dakota and a Basin and Range interpretation for it seems to conflict with nearby heat flow data and is inconsistent with other available geophysical information.

The major conclusion is that a heat flow province transition between Basin and Range and eastern United States types of heat flow occurs west of 103° W longitude in southwestern North Dakota. There is coincidence between the heat flow results reported here and a zone of anomalous electrical conductivity reported by Alabi, Camfield and Gough (1975), although the transition is better delineated by the heat flow data. The width of the transition zone between heat flow provinces is narrow (28 km) implying a shallow depth to partially molten lower crust or upper mantle. When used with experimental petrologic data for peridotite in the presence of excess water, temperature calculations suggest that a partial melt zone begins approximately at the depth of the Moho (45 to 55 km) as determined by seismic refraction data.

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