Petrology, Geochemistry and Isotope Geology

The Petrology - Isotope Geochemistry group in the department studies a wide range of petrologic problems. Among these are:

Archean Crustal Evolution- The mountain ranges of Wyoming expose some of the oldest rocks in North America, which is known as the Wyoming Archean province. This provides a natural laboratory for the study of the geochemical and tectonic evolution of Archean terranes. We are also studying komatiites, the hottest lavas that ever erupted on the Earth's surface and what they tell us about the temperature of the Archaean mantle.

The Origin of Granites - We have used mineral chemistry, whole rock and trace element geochemistry, and radiogenic isotopes to determine the sources and evolution of Precambrian granitic plutons in Wyoming. We then use these geochemical constraints to produce mathematical models to understand the origin of granites in general.

Island Arc Volcanism-We are studying the petrogenesis of island arc magmas (with special emphasis on the Aleutian arc) including the quantitative petrography of volcanic rocks; the evolution of mafic magma during magma ascent (both from a purely petrological approach, as well as by theoretical modeling); and the thermal and fluid dynamic constraints on magma generation, ascent and differentiation.

Igneous Processes within Mafic Plutons - Our group is currently studying many of the world's classic igneous plutons: the Bushveld Complex in South Africa (the world's largest layered intrusion. or is it an meteorite impact phenomenom), the Stillwater Complex in Montana, the Rum intrusion of Scotland and the Laramie Anorthosite which lies within a few miles of the University itself.

Mid-Ocean Ridge Processes - We have used submersibles and ocean drilling to sample the mantle and lowewr crust at slow and ultra-slow spreading ridges. We are currently investigating the processes of melt migration and extraction in the mantle and the origin of oceanic crust.

Metamorphism and Melting of Massive Sulfide Ore Bodies - We have discovered that massive sulfide ore bodies melt during medium- and high-grade metamorphism. We are studying metamorphosed ore bodies in Australia and Northern Manitoba to characterize the reactions that produce the melt, the changes in melt composition with metamorphic grade, and the paths these melts follow during differentiation.

Interaction between tectonics and rock deformation- The petrology-isotope geochemistry group works closely with the tectonics group to help understand the interaction between petrologic and tectonic processes.