TWH – Research by geologists indicates that each year the Atlantic Ocean widens by approximately 1.5 inches (3.8 cm). A team of scientists published new research that explains this widening. One of the key drivers of plate tectonics is that rising magma wells up from deep within the earth, and as a result, is building up the mid-Atlantic Ridge and causing the ocean to widen.
To explore this topic, The Wild Hunt spoke with geologist Kathleen Borealis. Borealis hosts the Borealis Meditation Podcast and is the founder of #WitchesWearMasks. She described herself as a “lifelong pagan, animist, witch, and geologist.”
Tectonic plate theory holds that moving plates cover the entire earth. Some plates support continents, while other plates support oceans.
Borealis explained, “The plates are the hard crust of the planet and they are all in motion on the surface. Where they meet is called a plate boundary and is where we tend to see the most active faulting. Oceanic plates are denser than continental plates. The continents tend to ‘float’ on the mantle happily while as the ocean crust gets older and cools more it wants to sink back into the mantle.”
She continued, “Where the oceanic plates pull apart the mantle is closer to the surface and rises as magma and forms the new plates. You can also get thinning and pulling apart of the continents like the American west Basin and Range, and the East African Rift zone. In this way, there is a recycling of material from the mantle to the surface.”
Most scientific writing strives for a dry, objective tone. In contrast, plate tectonics lends itself to an animist interpretation. Borealis described the earth as “a dynamic system and one that we are part of.”
She said that humans are familiar with what we can perceive – a solid planet. That solidity occurs on the surface. She continued, “The deep interior of the earth is the true engine of the planet. Personally, when I ground, I ground through to the interior of the planet. (I have an example meditation on my website). Like most systems, there is a cycle of creation and destruction.”
How plate tectonics work
As Borealis outlined, and in an article on Live Science explains in more detail the mechanics of plate tectonics, “Earth’s outer shell is divided into large slabs of solid rock, called ‘plates,’ that glide over Earth’s mantle, the rocky inner layer above Earth’s core.”
These plates vary in size. Geologists have sorted them by size into three categories: 1) major, 2) minor, and 3) micro.
Seven major tectonic plates exist: 1) African, 2) Antarctic, 3) Eurasian, 4) Indo-Australian, 5) North American, 6) Pacific, and 7) South American. It is the movements of these plates drive earthquakes, volcanoes, and tsunamis.
In the middle of the Atlantic, the North American plate meets the Eurasian plate. The South American plate also meets the African plate in the middle of the ocean. The Mid-Atlantic ridge runs north and south along those plate boundaries. Iceland is part of that ridge.
The Live Science article explains, “Earth’s solid outer layer, which includes the crust and the uppermost mantle, is called the lithosphere … Below the lithosphere is the asthenosphere —a viscous layer kept malleable by heat deep within the Earth. It lubricates the undersides of Earth’s tectonic plates, allowing the lithosphere to move around.”
Seismologist Nicholas van der Elst considers plate tectonics to be the “unifying theory of geology.”
Borealis said, “The current debate in tectonics has to do with the driving force of these movements.”
One of those forces would be the “ridge push.” That involves the generating of new material at mid-ocean ridges. That new material pushes the plates away from the ridge. Another would be a slab pull. That involves the pulling down of the plates as they sink into the mantle.
Borealis continued, “The slab pull is easier to study since there are usually areas on land, above this type of plate boundary. It is much harder to do seismic studies on the mid-ocean ridges because of their location.”
She explained that the recent EcoWatch article that discusses the new research involved a survey of the ocean floor, which used ocean bottom seismometers. Those instruments allowed for an examination and observation of the mantle below the ridge system.
Does a widening Atlantic affect sea level rise?
To a non-geologist, a widening ocean would seem to have some sort of relationship to sea-level rise. To a geologist like Borealis, the widening Atlantic involves, “the balance of forces between the different aspects of the system for oceanic plates. We have known for a very long time that the Atlantic is widening as new crust is being generated at the mid-ocean ridges. This is a slow process that has gradually opened the Atlantic basin.”
Climate change occurs on a longer time scale than that of the change in weather patterns, and geologic change occurs on a longer time scale yet than that of climate change.
Borealis went on to say, “The timescale of the opening of the Atlantic Basin is long compared to the timescale for sea-level rise from anthropogenic changing of the atmosphere. When we look at the geologic record, the changes in sea level are more strongly correlated to atmospheric changes and changes in the polar/continental ice sheets than plate tectonics. Therefore, this will not have a measurable impact on the current sea level issue.”
A message to Pagans
Borealis had a message for other Pagans, “As a Pagan who became a geologist I have always found that geologic study gave me new eyes to see the stories written in the landscape around me. I will always and forever advocate Pagans look into natural science and the natural history of where they live as a way to deepen their connection with our planet. There are lots of opportunities to learn and volunteer in your communities and citizen science projects you can be involved in. “
In the event of a major event like an earthquake, volcano, or tsunami, that generates a lot of interest, Borealis collects the questions and uses them as a basis for a podcast. People can follow her on Twitter, Instagram, via her podcast, and website.