Finding a missing tectonic plate

Scientists from the University of Houston have managed to detect signs of a controversial tectonic plate knows as the Resurrection Plate.

The existence of the Resurrection Plate is an issue long debated with many experts stating in the past that the plate never existed. However, according to the new study, published in October 2020, in the Journal Geological Society of America Bulletin, evidence that proves the existence of the plate was discovered. 

Plate tectonics is an accepted theory suggesting that the outer part of Earth is divided into smaller rigid pieces that move against or break away from each over. Those pieces are known as tectonic plates and tend to slide over a less rigid formation known as the mantle of the earth. The mechanism that drives the movements of plates is heat transfer between the different layers of the planet and can be explained by the discipline of thermodynamics. The types of potential movements are complex consisting of mid-ocean ridges where two plates detach and magma flows forming new crust and subduction zones where two plates collide with one being pushed under the crust. Over millions of years, those complicated mechanisms re-arrange entirely the landscape of Earth and re-shape the plates themselves.

The debate over the existence of the Resurrection plate is long-lasting and involves a complex interpretation of North America's regime, In particular, two volcanic chains formed at about the same time period, one in Alaska and the other in the coastal line of Washington and Oregon. The question is why these zones are distanced about 4,000km and geologists suggest two prevailing scenarios: 1) The volcanic chains were once together and were gradually separated or 2) They were interconnected through a plate boundary that does not exist anymore.

The authors of the study utilized a method known as mantle tomography which enables the reconstruction of the subsurface using seismic waves. In particular, they applied a 3-dimensional technique developed at the University of Houston specified for slab unfolding. The 3-dimensional reconstruction revealed that the debated plate is currently under the Kula and the Farallon plates.

The Kula plate used to be an oceanic plate before it was subducted under the North American plate and the region that used to occupy is now captured by the Pacific Plate. The Farallon Plate was also an oceanic plate that subducted beneath the North American Plate during the Jurassic period. The Resurrection Plate was detected near the volcanic belts proving the existence of a former subduction zone. “We believe we have direct evidence that the Resurrection plate existed. We are also trying to solve a debate and advocate for which side our data support,” S. Fuston, lead author of the study and a Ph.D. candidate at the University of Houston, stated.

The Resurrection Plate probably existed about 40 and 60 million years ago.

A video of the suggested model uploaded by S. Fuston can be found below.