Bill McIntosh

Dr. Bill McIntosh is an associate professor of geochemistry, and a volcanologist and geochronologist with the N.M. Bureau of Geology. He earned his bachelor’s at Princeton, his master’s at the University of Colorado-Boulder, and his Ph.D. at New Mexico Tech.

His chief research interests involve volcanoes of the southwestern United States and Antarctica over the last 40 million years. McIntosh has spent many austral summers at Tech’s Mount Erebus Volcano Observatory in Antarctica. He is among a handful of scientists who has expertise in Argon-Argon dating techniques.

My chief ongoing research interests involve volcanism of the southwestern U.S. and Antarctica during the last 40 million years. Both regions have experienced extensive volcanic activity well away from active plate tectonic margins, instead related to rifting and extension within continental plates.

The two main tools that I have been using to unravel the volcanic history of these regions are 40Ar/39Ar geochronology and paleomagnetism. Recent developments in the 40Ar/39Ar dating method allow highly increased precision as well as dating of very young and very small samples. This opens up exciting new possibilities, such as detailed reconstruction of the eruptive history of 30 million-year-old calderas, or using 10,000-year-old ash deposits in Antarctic ice cores to help understand the timing of changing global climates.

The combination of volcanic geology, 40Ar/39Ar dating, paleomagnetism, and other geochronologic techniques has opened up a wealth of other research avenues, including calibration of the time scale of worldwide geomagnetic reversals, and an attempt to determine the uplift history of the Tibetan Plateau.

• Volcanism
• Paleomagnetism
• Geochronology