Dean A. Zabel

Date of Award


Document Type


Degree Name

Master of Science (MS)


Physics & Astrophysics


Terrestrial heat flow measurements have been carried out at three sites in Southeastern North Dakota. The heat flow values were calculated from temperature gradients measured in three wells and thermal conductivities measured in the lab using samples from these wells.

At two of the sites values were obtained in Precambrian layers. Near Lidgerwood, North Dakota measurements in a layer of weathered Precambrian yielded a value of 1.21 HFU. At a site near Blanchard, North Dakota measurements in a Precambrian greenstone yielded a value of 0.76 HFU.

At a third site near Wheatland, North Dakota, no Precambrian layer was accessible for temperature gradient measurement. Temperature gradients (42.10 and 31.56°C/km) measured in two Cretaceous sedimentary layers at this site were found to be in the same range as the gradients (45.06, 49.97 and 23.51°C/km) measured in three corresponding Cretaceous sedimentary layers at the Lidgerwood site. These contrast with the gradients (12.58, 14.22 and 13.93°C/km) measured in Cretaceous and Ordovician sedimentary layers at the Blanchard site. This contrast in these temperature gradients is reflected in the calculated heat flows.

Differences in the radiogenic heat productions of the underlying Precambrian rocks is a likely explanation for the difference between the two heat flow values in the Precambrian materials at the Blanchard and Lidgerwood sites. The observed variations in the temperature gradients, and hence in the heat flows, in the sedimentary layers are probably a result of ground water movement in the different aquifers present at the three sites.