A description of the Marysville site is given. The drilling program, an environmental analysis, and a survey of geophysical surveys are described. A preliminary survey is presented of the area using aerial thermal infrared imaging techniques. (MOW).

This report describes the exploration of an anomalous site near Marysville, Montana, where the geothermal heat flow is about 10 times the regional average. The site arouses scientific interest because there are no surface manifestations such as young volcanics, hot springs, geysers, etc., within 20 miles of it. Also, there is significant economic interest in exploring the source of heat as a potential for the generation of electricity. Included herein are independent sections prepared by each contractor. Consequently, there is some overlapping information, generally presented from different viewpoints. The project consists of geophysical surveys in 1973 and 1974, the drilling of the deep well in the summer of 1974 to a depth of 6790 feet, the coring and logging of the well, the supporting scientific studies, and the data analysis. Since so much data are available on the Marysville system, it can serve as a testing and research area to help locate and understand similar systems. (GRA).