Continental Breakup & Mid-Ocean Ridge Dynamics

Continental breakup leads to the formation of spreading centers, which are the factories that generate new oceanic lithosphere, are key contributors to the release of heat and volatiles from the planet’s interior, and are drivers of plate tectonics. Yet, questions remain regarding the fundamental rift-to-drift process, modes of mantle deformation in extensional settings, crustal accretion processes, and extent and degree of melting. Oceanic lithosphere provides a window into mid-ocean ridge processes via structures preserved within it.

A key outstanding question pertaining to the rift-to-drift process is how the asthenosphere (re)organizes during the transition from the late stages of rifting to early stages of seafloor spreading. We can learn a lot from investigating passive margins, the remnants of lithosphere left over from continental breakup and successful rifting. For example, at the Eastern North American Margin Community Seismic Experiment (ENAM-CSE) we found anisotropy that is oriented parallel to the margine (perpendicular to what is epected) indicating that mantle flow during the earliest stages of seafloor spreading is not what we previously thought.