Northern Arizona University
2022-2023 Distinguished Lecturer
Active faulting and environmental change in young rifts
Active, young rift systems provide a unique window into the earliest stages of continental breakup, host earthquakes, and other geohazards, and are highly sensitive to environmental change. However, many questions remain about how fault systems accommodate rift opening and evolve over time, and how tectonic- and climate-driven processes conspire to shape rift evolution. Rift basin sediments record basin subsidence and fault slip, surface processes around and within the rift basin, and environmental changes, which can be used to tackle these questions. Here I will summarize new results from the Corinth Rift in Greece and the Malawi Rift in east Africa that provide new insights into these questions.
The Corinth Rift (Greece) is a young rift undergoing rapid extension, and it is one of the most seismically active regions in Europe. The rift hosts semi-isolated basins that oscillate between marine and lacustrine conditions due to sea level fluctuations associated with glacial cycles. Drilling during IODP Expedition 381 recovered rift basin sediments that include a high-resolution record of the last ~780 thousand years and reveal the timing and nature of dramatic environmental changes. Furthermore, integration of drilling and seismic imaging data provide evidence for fluctuations in the rate of sediment delivery to the basin associated with glacial cycles and a marked evolution in the activity of fault systems. I compare the Corinth Rift to Malawi Rift, a land-locked, early-stage rift in the southern East Africa Rift System that has experienced similarly dramatic climate-driven fluctuations in surface processes and an evolution in faulting, as documented by drilling as a part of the International Continental Scientific Drilling Program and seismic imaging.
Donna Shillington is an Associate Professor at Northern Arizona University. She studies tectonic, magmatic, and surface processes at ancient and active tectonic boundaries. She has sailed on one IODP and one ODP expedition and has participated in or led 20 other marine research expeditions and onshore field programs, including to other ancient and active rift systems.