Date of Award
Master of Arts
Geological and Environmental Sciences
Dr. John D. Grace
Masters Thesis-Open Access
The purpose of this study is to ascertain the petrogensis of the Hell Canyon pluton through the use of standard petrographic techniques and three dimensional mineralogical variability trends. It is intended that this study will provide additional information to the ongoing investigations of the Boulder batholith sequence, of which this intrusion is a part.
The Boulder batholith is located in the Southeastern part of the Northern Rocky Mountains physiographic province in southwestern Montana. This province is typified by numerous rugged mountain ranges of which there are two distinct types. The Idahotype( Rocky Mountain Association of Geologists, 1972) mountains, erosional mountains carved in the Idaho batholith, show little individuality due to the uniform nature of the underlying material from which they are carved. In contrast to the Idaho-type mountains is the so called Montana-type, found in all parts of the Northern Rocky Mountains physiographic province excluding the Idaho batholith. Montanatype( Rocky Mountain Association of Geologists, 1972) mountains are linear, northwest trending ranges, separated by broad basins. They are primarily structural mountains similar to those of the Basin and Range province.
Johanns, William M., "Petrogenetic and Trend Surface Analysis of Hell Canyon Pluton, Montana" (1973). Masters Theses. 4434.