Grant: Discovery Grants Program - Individual

The objective of my research is to better understand the nature and duration of mountain-building events, a consequence of plate-tectonics. This is done by careful mapping of rock units where they are well exposed, such as coastal Newfoundland, followed by examination of their minerals under the microscope, and determination of their ages of crystallization. To determine the rate at which mountain- building occurs and the rates at which rocks heat up as they are deeply buried, then melt, and then cool down again, radiometric ages are determined for rocks by measuring the amount of lead (Pb) produced by the decay of uranium (U) that is present in certain tiny minerals (zircon, monazite) in the rock. U/Pb ages of minerals are measured in the radiogenic isotope laboratory in the Department of Earth Sciences at Memorial University, one of only a few such labs in Canada with an extremely low level of background lead contamination. With very miniaturized chemical processing techniques that can cleanly separate less than 1 millionth of a gram of lead and measure it precisely, we can determine the age of a single zircon crystal less than one tenth of a millimeter in length. These crystals act as tiny clocks recording the time elapsed since they crystallized from a molten lava, or during a high-temperature heating of deeply buried rocks. With precise ages, which for a geologist is +/-1 million years or less, it is possible to resolve events that happened in quick succession in the development of a mountain range over geological time.