The Devonian geological period, which lasted roughly 419 million to 359 million years ago, experienced a mantle plume that supposedly resulted in a major geological activity.
This led to the break up of the continental crust and opened the Mongol-Okhotsk Ocean, the remains of which are part of today’s Mongolia.
A new study conducted by a team of geologists from the National Spanish Research Council in Madrid, the Chinese Academy of Sciences, and several other institutions aimed to understand the Wilson Cycle and the mechanism behind how the continents broke up.
Rebuilding the breakup of the supercontinent
The Earth’s mantle which tore apart the land where Mongolia is located today, sprouted an ocean that lasted about 115 million years.
Daniel Pastor-Galán, the study’s co-author and a geoscientist at the National Spanish Research Council in Madrid explained that these are slow, broad-scale processes that progress by less than an inch per year.
“It’s telling us about processes in the earth that are not very easy to understand and that are also not very easy to see,” he told Live Science.
Now, the experts have recreated an almost exact scenario of how the supercontinent – Pangea separated 250 million years ago.
Fascinated by the volcanic rocks in northwestern Mongolia that date back to the Devonian period, the researchers investigated the geological history and processes associated with the Central Asian Orogenic Belt (CAOB) and the opening of the Mongol-Okhotsk Ocean (MOO).
Mantle plume evoked the separation in Mongolia land
According to the study, the mantle plume – a stream of particularly hot, buoyant mantle rock evoked the breakup of continents, weakening the lithosphere, facilitating the formation of this ocean within the Central Asian Orogenic Belt.
Mingshuai Zhu, study lead author a professor of geology and geophysics at the Chinese Academy of Sciences, told Live Science:
“Mantle plumes are usually involved in the first stage of the Wilson cycle: the breakup of continents and opening of the ocean, such as the Atlantic Ocean.”
He further explained that sometimes the separation can occur in the center of a solid chunk of continent. However, in this case, the geology was more complex due to the plume tearing apart the crust which earlier formed through accretion.
“Weak spots between the accreted microcontinents, combined with the plume, probably helped the ocean to form,” Zhu said.
Pastor-Galán explained that the ocean closed in the same spot that it opened, which is a common pattern in ocean life cycles. This is based on the snapshot of the ocean’s opening in this study.
“A good thing is that a hotspot is relatively stable so they keep on, for many millions of years, in the same place,” he stated.
“As continents in the crust move over the mantle hotspot, the hotspot leaves behind volcanic rocks and a tell-tale chemistry; this helps researchers track plate motion over millennia.”
Asia is no longer accumulating new microcontinents, but the formation of the Mongol-Okhotsk Ocean was likely similar to the current geological activity at the Red Sea.
There, the crust is spreading by about 0.4 inches (1 centimeter) per year, potentially leading to the creation of a new ocean in eastern Africa over tens of millions of years. However, it is uncertain whether other geological forces might prevent this new ocean from fully forming.
The study was published on May 16 in the journal – Geophysical Research Letter.
