A team of scientists has discovered that a rare type of diamond may indicate that water can penetrate deeper than previously thought.
Although more than 70% of our planet is covered by water, there are more than 322 kilometers of mineral-containing water underground, including the upper mantle, the semi-elastic layer on which the crust “floats”, the area most affected by tectonics. activity.
Scientists have long believed that minerals may contain less water as the upper mantle migrates into the hotter and denser lower mantle.
But in a new study published on September 26 in Nature Geoscience, scientists found that diamonds contain inclusions or small pieces of other minerals and may contain more water and appear to be present at the boundary between the upper and lower mantle.
The findings suggest there may be more water on Earth than scientists thought, and it could affect our understanding of the deep water cycle and plate tectonics.
The results were unexpected, according to the study’s lead author Tingting Gu, who is now a mineral physicist at Purdue University in Indiana but was a researcher at the Gemological Institute of America in New York when conducting the study.
Jo and colleagues studied type IaB, a rare type of diamond from the Karowe mine in Botswana that forms deep in the ground and often stays in the ground for long periods of time.
To study the diamonds, the team used “non-destructive” methods of analysis, including Raman micro-spectroscopy, which uses lasers to detect some of the material’s physical properties, and X-rays. diffraction to view the internal structure of the diamond without cutting it.
Recently discovered in a diamond mine in Botswana, the diamond is a contaminated rock containing traces of ringwoodite, ferropericlase, enstatite, and other minerals that indicate the diamonds formed 660 kilometers (410 mi) below. of the Earth’s surface.
Inside the diamond inclusions, scientists found a mineral called ringwoodite, which has the same chemical composition as olivine, the raw material for the upper mantle, but because it was formed under extreme heat and pressure. , scientists just couldn’t find it until 2008. In the case of the meteorite, according to Joe.
Ringwoodite is typically found in the transition zone between the upper and lower mantle, between 410 and 660 km (255 and 410 mi) below the Earth’s surface, and may contain more water than what is believed to be “bridgemanite” and “ferroperclase” mineral. The authors of the study noted that the mantle (mantle) dominates the lower part.
But instead of minerals normally found in the transition zone, the area around this “ringwoodite” is mineral forms unique to the lower mantle.
Because the encapsulated diamonds retain the properties of these minerals as they appear deep in the earth, scientists can find the temperatures and pressures these minerals endure, and estimate the minerals which is 660 km (410 mi) below the surface. outer boundaries of the transition zone.
The analysis also showed that ringwood is likely in the process of breaking down into minerals in the lower mantle, which is more common in a watery or saturated environment, and that water can penetrate the lower mantle from the transition zone.
Scientists note that although previous research has found some mineral forms from the lower mantle in diamond inclusions, the combination of materials in this inclusion is unique.
It is also unclear from previous findings whether these minerals indicate the presence of water-containing minerals in the lower mantle, the study authors said. Because no rocks 11 km (7 miles) below the Earth’s surface have been directly sampled, diamond inclusions are one of the few sources of minerals from the Earth’s mantle.
Jo explained that the findings could have implications for understanding the deep water cycle, or the water cycle between the planet’s surface and its deep interior.
“The timescale of the water cycle is actually shorter if it can be stored deeper,” he added, meaning less time is required for water to replenish itself when stored deeper.
Jo said that scientists hope that the results of this study can be incorporated into models of how water in the mantle influences processes such as the Earth’s internal convection current, and that the findings may also affect in models of plate tectonics. This current heats the Earth’s mantle unevenly, fueling plate tectonics, which causes the hottest parts to rise and move across the Earth’s plates over millions of years.
Source: Life Sciences
Source: Arabic RT
