James Pierce L&S Sciences
Constraining the assembly of North America ca. 1.85 billion years ago
The geological core of North America, known as Laurentia, is a product of a collision that occurred some 1.85 billion years ago. The Superior Craton of eastern Canada collided with the Hearne and Wyoming Cratons to the west, creating the Trans-Hudson Orogenic Belt and the foundation for Earths putative first supercontinent, Nuna. As igneous rocks form, they record the direction and magnitude of Earths magnetic field as remanent magnetism. Ferromagnetic minerals, such as magnetite, align their magnetization in the direction of the prevailing magnetic field. After collecting samples that date to the creation of Laurentia, a magnetometer will be used for thermal demagnetization, a procedure that detects the magnetic moment (direction and magnitude) of the magnetization preserved in the sample. Measuring this magnetic imprint will allow me to reconstruct the movement of these cratons through time and better understand the Trans-Hudson Orogen and the assembly of North America.