Earth Dynamics and Environments
The Earth is the only planet that we know of that supports life today. Yet, when geophysical models and the geological record are examined, it becomes clear that the current environment is the unique result of a delicate balance of forces. These triggers and feedbacks span the solid Earth, atmosphere and oceans. Knowledge of the geophysical evolution of Earth dynamics and surface environments that cradled early life can elucidate the history of life on Earth and inform constraints on the habitability of other planets. My research aims and projects stem from two driving questions:
1. Earth Dynamics: How have Earth’s dynamics varied through its history?
2. Earth Environments: What are the tempos and triggers of fundamental changes in global and local marine oxygen?
I integrate computational, field, and laboratory techniques within a robust geologic framework. I have experience creatively applying this combined approach to geologic questions as I have written geodynamic codes, carried out fieldwork with international teams in Northwest Canada, Death Valley, the Grand Canyon, and Greenland, and led field campaigns to the Pacific Northwest and the North American Great Lakes region. Subsequent paleomagnetic and geochemical laboratory analyses I have completed at Boise State, Harvard and Yale Universities and MIT. Almost all of my projects are multidisciplinary and involve collaborations with colleagues of diverse expertise.
Research theme 1: Everyone loves jigsaw puzzles. As a geologist with a foundation in physics, I examine rocks collected on my expeditions to sites such as the Grand Canyon and Greenland, along with cutting-edge laboratory techniques to solve the world’s biggest jigsaw puzzle: rearranging the Earth’s plates to understand what the world looked like millions to billions of years ago. My research has several goals, one of which is to identify when the ancient Earth’s crust was first broken up into a patchwork of moving plates. The established theory of “plate tectonics” recognizes that the Earth’s surface is currently composed of approximately nine major plates. As they slide across the Earth’s surface, some get bigger, some break apart, and others collide. These motions facilitate crucial recycling of nutrients for life.
Research theme 2: Did you know that the Earth’s atmosphere hasn’t always had all that oxygen you breathe? The early Earth was a very different inhospitable place, lacking the oxygenated atmosphere crucial for large complex life on Earth today. We know that since the Earth’s birth, the oxygen rose to modern day levels via two steps, first about two billion years ago, and later about 700 million years ago. The triggers and details of the subsequent trajectory from low oxygen to the presently high oxygen levels in the atmosphere and oceans remain uncertain. Furthermore, current anthropogenic global warming is contributing to the decrease of oxygen in the modern ocean. My research focuses on constraining the tempos and triggers of oxygenation, as well as understanding ocean deoxygenation associated with warm climate states.
Department of Earth, Atmospheric and Planetary Science
Massachusetts Institute of Technology
77 Massachusetts Avenue
Cambridge, MA 02139, USA
Featured Photo: Greenland, July 2019. C. Nichols