Study reveals the extent of the sun's influence on the depth of the Earth

A new study by scientists from China and Romania has revealed that solar radiation can affect the Earth's deep interior.

According to scientists from the Institute of Geology and Geophysics (IGG) of the Chinese Academy of Sciences, China University of Geosciences, and the University of Bucharest, solar radiation varies with latitude, creating temperature gradients at the sea surface that affect the distribution of marine life.

Carbon-rich organisms are transported into the Earth's interior by the process of subduction of oceanic plates (subduction of oceanic plates is responsible for some of the world's largest earthquakes and volcanic eruptions,  as  the subducting plate melts as it descends into the mantle, forming magma that rises to the surface and causes volcanic eruptions). This process greatly affects the "redox" state of arc magma (where magma rises to form an arc of volcanoes).

The scientists analyzed data from thousands of magma samples, including those from deep underground and undersea, collected by geologists around the world. They examined tiny melt inclusions within peridot minerals and bulk rock data to determine the “redox” state of arc magma.

The "redox" state of an arc magma refers to the balance between reducing (losing oxygen or gaining electrons) and oxidizing (gaining oxygen or losing electrons) conditions within the magma formed in volcanic arcs.

Scientists have found that solar radiation, which varies across latitudes, affects the different distribution of marine organisms in the water column. These organisms, in turn, enter the Earth's mantle and change its "oxidation-reduction" processes in different ways.

The study shows for the first time how the sun works in the deepest layers of our planet, revealing that magma at low latitudes is less oxidized than at higher latitudes.

"This unexpected pattern suggests that under the influence of solar radiation, the Earth's surface environment and climate have a profound impact on processes in the mantle," said Wan Bo, co-author of the study and a researcher at the Institute of Geology and Geophysics.

According to the scientists, many metal ores, such as copper, tin and lithium, are sensitive to redox conditions, and understanding the spatial and temporal distribution of redox conditions in global subduction zones has significant implications for predicting the locations and availability of these resources.

The study was published in the journal Nature Communications.