Geophysicists confirm ancestral tectonic plates


The pun is inevitable: two geologists at the University of Houston found, using 3D mapping technology, evidence that shows that the Resurrection – an ancient tectonic plate on what is now the North American coast facing the Pacific Ocean – really existed.

To the east of where Alaska is today, measurements have detected the presence of large amounts of magma, which could be the consequence of intense volcanic activity in the region. So while some geophysicists questioned the existence of a third tectonic plate in the region, in addition to the already known Kula and Farallon, others argued that a puzzle piece was missing.

For them, the hypothesis is that, like the others, it has been subdued – it moved under the Earth’s mantle, on the shores of the Pacific Ocean, between 40 million and 60 million years ago. In the image below, the Resurrection would be between the Kula and Farallon plates, having been pushed under what is now North America by the Pacific Plate.

“Volcanoes are formed at the boundaries of the plates; the more plates there are, the more volcanoes there are, the activity of which also affects climate change. Therefore, to model the Earth itself to understand how the climate has changed, it is necessary to know how many volcanoes there were on the planet “said geologist Jonny Wu, author of the study, now published in the GSA Bulletin, together with doctoral student Spencer Fuston.

Unfolding the past

To find out if Resurrection existed or not, a 3D technique developed by the UH Center for Tectonics and Tomography, called slab unfolding (plate unfolding), was used to redo the geological scenario 60 million years ago, reconstructing the way tectonic plates in the Pacific Ocean were positioned at the beginning of the Cenozoic Era.

At the time, the lithosphere (rigid and outermost layer of the earth’s crest) at the edge of the Pacific in North America was divided into tectonic plates Kula and Farallon. The question was whether a third plate, the hypothetical Resurrection, formed a volcanic belt across Alaska and the state of Washington.


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