DrSam Kelley

I am a glacial geologist with an interest in the connections between earth surface processes, ice sheets and glaciers, and changes in climate. My research is field-oriented, focusing on glacial-geologic archives, such as glacial deposits and sedimentary archives of past change, which hold information about changes in past ice masses and paleoclimate. One of the tools I use in my work is terrestrial cosmogenic nuclide (TCN) concentrations to make connections between past climate perturbations and changes in the extent of paleo-ice-masses. Specifically, TCN can be used as a dating technique to provide precise radiometric constraints on geologic processes, such as when an ice mass recedes off a landscape, or when a fault scarp is exposed by an earthquake. The principle behind the dating technique is that a cosmogenic nuclide is produced through the bombardment of a rock surface by secondary cosmic rays, and this production of the cosmogenic isotope begins as soon as the rock surface is no longer shielded by overlying ice or sediment. Through measuring the quantity of nuclides present and understanding the rate at which they are produced, I am able to calculate the time when the surface was exposed. Beyond their use as a dating technique, TCN can be used to assess long-term landscape stability or provide information about erosion and uplift rates In addition to paleoclimate research, I also examine glacial processes related to the production and provenance of glacial sediments for applications in the resource exploration industry. This work uses mineral and geochemical attributes of glacial sediment, in conjunction with knowledge about the local glacial geology, to examine glacial dispersal patterns, the net result of glacial entrainment, transport, and deposition.