- The Melanesian Boundary Plateau was formed in four different volcanic stages
- Created an “oceanic mid-plate superstructure” approximately the same size as Britain.
- Read more: Newly discovered 50-mile fault line could cause massive tsunami
Scientists have solved the mystery behind how a volcanic superstructure the size of Idaho formed beneath the Pacific Ocean.
Dubbed the Melanesian Border Plateau, this more than 80,500-square-mile structure was created between 145 and 66 million years ago, when dinosaurs ruled the Earth, and continues to grow today. An international research team determined that.
Researchers used seismic data, rock samples and computer models to identify four periods of volcanic eruptions deep beneath the Earth’s surface that began 100 million years ago.
It turns out that submerged structures also have characteristics. A rare element used in smartphones, computers, medical equipment, etc.
In a new study, an international team of scientists led by Kevin Conrad, assistant professor of geosciences at the University of Nevada, Las Vegas, assembled available data to determine the age of the Melanesian Border Plateau.
During a 2013 marine expedition, Conrad and colleagues dredged deeply along the slopes of the Melanesian Border Plateau from aboard a ship and collected rock samples from multiple locations around the Melanesian Border Plateau.
Scientists have had fragmentary knowledge of how the Melanesian border plateau was formed, but until now they have been unable to build a comprehensive picture.
Analyzing the age and chemical composition of these rocks helped put the pieces of the puzzle together.
The survey is not an easy task, as water depths in the area can reach up to 600 feet.
The work offers a glimpse into the forces that built the Earth as we know it, and may provide insight into what the Earth’s future will look like.
There are many submarine volcanoes in the Earth’s oceans. Their eruptions formed archipelagos like Hawaii and Japan, and undersea mountains and ridges that never penetrated the ocean’s surface.
Some of the structures created by volcanic activity accumulate into larger geological formations over time, usually by one major event at the edges of the plates that make up the Earth’s crust, or where two plates meet. will be formed.
These boundaries between plates are known to be sites of volcanic activity, so it makes sense that igneous (volcanic) rock formations would arise from them.
However, other structures have formed over time in the center of the plate, where volcanic activity is less pronounced. This makes its origin less simple.
The Melanesian Border Plateau is one such structure, which Conrad and colleagues refer to as the oceanic mid-plate superstructure.
Upon first inspection, it may appear to be a Melanesian border plateau, formed by the upwelling of giant lava from beneath the earth’s surface.
However, if such an event occurred, chunks of volcanic material could have been released into the water and recorded beyond the local area.
“The Pacific Basin has several characteristics. [scientists] We only have one sample, and it looks like a very large, single event,” Conrad said. live science. “Sampling these features in detail may reveal that they were actually built over multiple pulses over tens of millions of years and have no significant impact on the environment.”
Rather, four distinct periods of activity, all with different origins, appear to have built up the Melanesian Border Plateau over time.
A new study says the plateau began to form due to submarine volcanic activity during the Cretaceous Period, between 145 million and 66 million years ago, when dinosaurs still roamed the Earth.
During this first period, a volcanic hotspot called the Louisville Hotspot burned away the outermost layer of the Earth’s crust, the lithosphere, forming a ridge and several small underwater mountain ranges near what would eventually become the Melanesian Border Plateau .
Hotspots form when the lithosphere passes over magma near the surface.
This was just the beginning of a series of volcanic activities.
Some of the earliest mammals spread across Earth during the Eocene epoch, from 54.8 million years ago to 33.7 million years ago.
At the same time, the lithosphere passed over the Rurutu-Arago hotspot, in turn forming oceanic islands and underwater mountain ranges.
The third event occurred during the Miocene epoch, from 23 million years ago to 5.3 million years ago. Around that time, whales and sharks became more abundant in the ocean, and the first apes began to walk upright.
At this time, some of the existing islands and hotspots were reinvigorated as the region passed through the Samoan hotspot.
“The same conduit that magma passed through 45 million years ago is now a pre-existing weak spot that magma began to pass through 13 million years ago,” Conrad said. live science.
The period from then to the present represents the ongoing fourth pulse of the formation of the Melanesian border plateau.
Based on the ages of lava flows previously determined by other researchers, this latest phase of the Melanesian Border Plateau appears to have been caused by quite different factors than the previous three phases.
The deformation of the Tonga Trench plate boundary causes new volcanic eruptions, which continue to deposit and deposit rocks.
The results were published in the January issue Earth and Planetary Science Letters.
Conrad says the complex topography of the Melanesian border plateau may not actually be that unique.
Other oceanic mid-plate superstructures probably also exist, especially in the South Pacific, where volcanic activity continues to shape the region today, he said.
The volcanic activity that shapes this area poses no immediate threat to people.
But understanding it better provides insight into how other ocean floor structures formed.