The role of magma in the birth of the Atlantic Ocean

The Atlantic Ocean was formed 200 million years ago when the supercontinent Pangea broke apart. The continental crust was stretched and fractured. Scientists can look at the structure of the eastern North American margin, where the Atlantic Ocean and North America meet. Clues about geological processes that accompanied continental breakup can be found in the composition of the crust and upper mantle.

magmatism may be important in this process. The portion of the eastern North American margin associated with the eastern United States has thick sections of rock that are considered to be magma-rich. There are parts of the margin that are poor in magma. A high-resolution seismic model was developed to investigate the Nova Scotia margin.

The team used a technique known as full- wave inversion to analyze the waves captured by 78 ocean bottom seismometers. The researchers used a high-resolution velocity model to show how seismic waves were reflected at different depths and positions.

On the basis of the data, Jian and colleagues were able to identify the stages of rift formation. There are features that suggest that a magmatic event preceded the final continental break up. There is a boundary between continental and oceanic crust.

The results show a new picture of what happened in a region off of northeastern Nova Scotia that has been thought to be amagmatic. Evidence of a role for magmatism in continental breakup is supported by the findings.

More information: Hanchao Jian et al, New Insights Into the Rift to Drift Transition Across the Northeastern Nova Scotian Margin From Wide‐Angle Seismic Waveform Inversion and Reflection Imaging, Journal of Geophysical Research: Solid Earth (2021). DOI: 10.1029/2021JB022201 Journal information: Journal of Geophysical Research: Solid Earth

The story was re-posted by the American Geophysical Union. The original story can be read here.

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