Restructured: Segments of the Mid-Atlantic Ridge Formed During the Rift-to-Ridge Process

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Source: Journal of Geophysical Research: Solid Earth

The process of continental breakup includes a significant amount of volcanic activity and the addition of magma to the continental crust. After the continent breaks apart, the passive margin transforms into a mid-ocean ridge spreading center which produces oceanic crust. It is of interest to determine if the division of the spreading center is influenced by the previous structure and size of magma concentration along the passive margin.

In 2023, Brandl and colleagues explored the composition and types of rocks beneath the surface of the east coast of the United States, up to depths of 10 to 20 kilometers. They used ocean bottom seismometers to make their measurements and discovered areas with increased magmatic activity at scales of 30 to 100 kilometers, with gaps as wide as 30 kilometers. This type of small-scale magmatic segmentation has not previously been observed, except in current continental rifts, while there has been some variation observed along other passive margins.

This research, in addition to research conducted in the Main Ethiopian Rift, suggests that oblique rifting plays a significant role in directing extension and the formation of smaller magma segments. Interestingly, these magma breaks are in line with fracture zones of the Mid-Atlantic Ridge, indicating that the segmentation of the rift influences the later segmentation of the spreading center.

Citation: Brandl, C. C., Worthington, L. L., Magnani, M. B., Shillington, D. J., & Luckie, T. W. (2023). Discontinuous igneous addition along the Eastern North American Margin beneath the East Coast Magnetic Anomaly. Journal of Geophysical Research: Solid Earth, 128, e2023JB026459. https://doi.org/10.1029/2023JB026459

“Emilie Hooft, an Associate Editor at JGR: Solid Earth”

Text © 2023. The authors. CC BY-NC-ND 3.0

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