Journal
TECTONOPHYSICS
Volume 744, Issue -, Pages 403-421Publisher
ELSEVIER
DOI: 10.1016/j.tecto.2018.07.021
Keywords
Continental rifting; Volcanic passive margins; Midcontinent Rift
Categories
Funding
- NSF [EAR-1550108, EAR-1148088, EAR-1549764, EAR-0952345, EAR-0952154]
Ask authors/readers for more resources
Continental rifts evolve along two possible paths. In one, a rift successfully evolves into seafloor spreading, leaving the rift structures buried beneath thick sedimentary and volcanic rocks at a passive continental margin. Alternatively, the rift fails and remains as a fossil feature within a continent. We consider insights into these processes from studies of North America's Midcontinent Rift (MCR). The MCR combines the linear geometry of a rift formed at a plate boundary and the huge igneous rock volume of a Large Igneous Province. The rift is a fault bounded basin filled with volcanics and sediments, which record a history of extension, volcanism, sedimentation, subsidence, and inversion. The MCR came close to evolving into an oceanic spreading center, but it instead failed and thus records a late stage of rifting. It thus preserves a snapshot of a stage of the process by which actively extending rifts, characterized by upwelling mantle and negative gravity anomalies, evolve either into failed and often inverted rifts without upwelling mantle and positive gravity anomalies or into passive continental margins. Many rifts can be viewed as following a generally similar evolutionary sequence, within which a complex combination of factors control the variability of structures within and among rifts. Study of the MCR also gives insight into passive continental margins. The MCR gives a snapshot of deposition of a thick, dense, and highly magnetized volcanic section during rifting. Surface exposures, seismic, and gravity data delineate a rift basin filled by inward dipping flood basalt layers, underlain by thinned and underplated crust. The fact that the MCR shows many features of a rifted volcanic margin suggests that it came close to continental breakup before it failed, and illustrates how many passive margin features form prior to breakup.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available