Nicolas Anderson

Using paleomagnetism and geochronology to test a bifurcating mantle plume hypothesis

1.1 billion years ago, Laurentia, the Craton which makes up majority of modern North America’s landmass, was rifting apart in the Lake Superior region and growing in the American Southwest. Both of these processes produce magma. As magma cools, the magnetic minerals within align with Earth’s magnetic field and these alignments can be used to determine the age of a rock (paleomagnetism). Similarly, small crystals formed within the magma can also indicate a rocks age (geochronology). There is a likely connection between the locations due to similar timing of emplacement and geochemical signals. Recent, high-quality data collected for Lake Superior indicate a high volume, short duration magmatic event 1096 million years ago, which is inconsistent with a typical rift (long duration, low volume). It is hypothesized that an upwelling magma plume encountered topography at the base of the crust, bifurcating it, sending some magma into the rift, with the rest emptying into the American Southwest. Previous geochronology of the American Southwest is plagued by inaccuracy. Improved geochronology and paleomagnetism of the region will better establish their relationship.

Message to Sponsor

I am beyond grateful to the McKinley fund for supporting my project. This research fellowship has given me the opportunity to get my hands dirty in the field and participate in meaningful geological research at Berkeley, even in the midst of a global pandemic. This research is laying the ground work for my thesis and is integral to preparing me for continued research in graduate school. I am so thankful for this amazing opportunity!
  • Major: Geology
  • Sponsor: McKinley Fund
  • Mentor: Nicholas Swanson-Hysell