Research Interests


Jack Satterly Geochronology Laboratory

Understanding the breadth and detail of geologic time has had a huge impact on culture as well as on science. The first valid measurement of the true age of the Earth was only made about 50 years ago and greatly expanded our vision of the universe. Since then dates on rocks, minerals and meteorites have often furnished decisive evidence for or against competing theories on the origin and evolution of our planet. My work and that of my group at the Jack Satterly Geochronology Laboratory focuses on the precise measurement of geologic time. Our tool of choice is the uranium-lead isotopic system in the mineral zircon. There are several other long-lived radioactive decay systems and other rock/mineral hosts that we can use but zircon usually gives the most accurate ages for the geologic events that have accompanied significant phases in Earth’s development. Our lab is the birthplace of high precision zircon dating thanks to the pioneering work of its founding director, Tom Krogh. It has consistently maintained the world’s lowest contamination levels, giving us the ability to analyze the smallest samples. This is a critical advantage in selecting the most pristine and representative material.

Studies of Earth’s past often produce a mass of poorly connected observations due to the incomplete nature of the geologic record. It is the geologist’s task to connect these observations into a coherent model that describes a sequence of events. These models are usually based on some theory about how the Earth works, such as plate tectonics. With precise ages we can work out the sequence and duration of events in the remote past and compare this to what is predicted by different models. Geochronology is one of the few methods in Earth science that allows robust testing of theories, which is how scientific progress is made.

Good geochronology is demanding. It requires the highest level of laboratory discipline but geochronologists can choose to work on diverse problems throughout the world with other specialists. This gives a broader overview of Earth science than many other fields and the chance to contribute to a large range of other disciplines. The isotope field is now expanding rapidly due to development of new instrumentation that opens up most of the periodic table to precise isotopic analysis. New applications of geochronology and isotope geoscience are limited only by one’s imagination.

The work of colleagues at our lab, students and myself has contributed to solving a wide range of problems. Some of this work is central to my research, in some of it I was involved only as a facilitator and source of advice. Together it represents the collective effort of an outstanding research team. Below are a few examples.