The questions I address in my research cover three main areas:
How do environmental materials get magnetized? And what can the magnetic properties of rocks and sediments tell us about the environment of the past? I focus mainly on using magnetic anisotropy to explore material flow, compaction, and crystallization. I also use magnetic minerals to find the sources of sediments and to investigate mineralogical changes in those sediments. Projects addressing these questions are tagged EnvMag below.
Earth’s Ancient Magnetic Field
What was Earth’s magnetic field like at times when our planet’s structure and deep-Earth processes were considerably different from today? Much of my graduate work focused on getting reliable records of Earth’s magnetic field intensity from the Archean Eon, early in our planetary history. Projects addressing these questions are tagged Paleomag below.
Geoscience Teaching and Learning
A large body of literature exists to indicate that students learn best when actively involved in constructing their own knowledge. How can we model the process of science in general and geoscience in particular to engage students in learning? I am particularly interested in how geospatial technology can help students develop geological ideas, and in how we teach issues related to probabilistic thinking and risk.
If you are interested in getting involved, check out the projects below!
Magnetic minerals, because of their iron content, are sensitive indicators of chemical weathering. The magnetic properties of soils and loess (windblown silt deposits, somewhat modified by soil formation) can therefore help us understand the moisture and temperature conditions in which soil and loess landscapes formed.
Sediments eroded from the Himalayas during their 50 million years of uplift have largely been carried out to sea and deposited in great cone-shaped piles to the east and west of the Indian subcontinent. The Bengal Fan, the deposit fed by the modern Ganges and Brahmaputra rivers, is by far the larger of these sediment accumulations. In the winter of 2015, I sailed on International Ocean Drilling Program Expedition 354 to sample these sediments. We collected cores from a transect across the middle of the Bengal Fan to track the flow of detritus from the rising Himalayas to its ultimate resting place in the Bay of Bengal.
Layered intrusions are the solid remains of ancient underground magma systems. Unlike granites or other relatively silica-rich rocks, layered intrusions are often rich in iron and magnesium. The squishing and squashing as magma is injected into the crust, the density contrasts between magmas and crystals, and the chemical changes in magma, crystals, and hydrothermal fluids …