Reconstructing Taiwan’s Metamorphic Core
Dr. Jonathan C. Lewis
This summer, I am working with Dr. Jonathan C. Lewis to document the plastic to brittle transition of rocks in the eastern Central Range of Taiwan as they exhume to the surface. We are able to do this by analyzing plastic and brittle deformation
data collected from natural river outcrops in previous field seasons. Brittle deformation is described as a geologic feature fractures, and plastic deformation is described as a geologic feature flowing without fracturing. Using software such
as Stereonet, Fault Kin, and T-Tecto, we are able to derive the geometry and kinematics of these structures that provide constraints to the metamorphic core. Geometric analysis refers to the size and orientation of a structure while kinematic
analysis refers to the path that rocks will take during a deformation event. While working with this data we are in search of patterns throughout transitions to show where the rocks are moving.
Taiwan is an island off the coast of China that has a population of over 23 million and has some of the highest exhumation rates in the world, uplifting up to 8mm per year. The constant plate movement creates steep topography, earthquakes, and
high erosion rates that can be dangerous to the population. 2D models have been created but none have been created in 3D. 2D models tend to only show the way the rocks are stretching which could influence earthquake effects on the landscape.
But by providing the 3D models, we will able to show the geometry and kinematics of structures in Taiwan. We are hoping to provide these constraints to have a better understanding of Taiwan's geology.