Geologists have achieved a significant milestone by drilling 1,268 metres below the seafloor in the North Atlantic Ocean, marking the deepest penetration into Earth’s mantle ever recorded. The analysis of this rock core is shedding new light on the evolution of our planet’s outer layers and may even provide insights into the origins of life.
Earth’s structure consists of various layers, including a solid outer crust, an upper and lower mantle, and a core. The upper mantle, situated beneath the crust, is primarily composed of peridotite, a magnesium-rich rock that plays a crucial role in geological processes such as earthquakes, the water cycle, and volcanic activity.
“Until now, we’ve only accessed small fragments of the mantle,” noted a researcher involved in the study. “However, there are several locations where the mantle is exposed on the seafloor.”
One such site is the Atlantis Massif, an underwater mountain located near a volcanically active region of the mid-Atlantic ridge. Here, the continuous surfacing and melting of mantle material contribute to local volcanic activity. Additionally, seawater that seeps deeper into the mantle experiences heating, producing chemical compounds like methane, which rise through hydrothermal vents and serve as fuel for microbial life.
“This region acts as a sort of chemical kitchen beneath the surface,” the researcher explained.
Initially, the drilling team set out to reach 200 metres into the mantle using their drilling vessel, but due to unexpectedly successful drilling, they decided to extend their reach and ultimately achieved the remarkable depth of 1,268 metres.
Upon examining the drill core samples, researchers discovered significantly lower levels of a mineral called pyroxene compared to other global mantle samples. This finding indicates that this specific mantle section has experienced considerable melting in the past, leading to a depletion of pyroxene.
Researchers aim to reconstruct the melting process within this unique region to enhance understanding of how the mantle transitions to molten rock, which ultimately feeds oceanic volcanoes.
Some scientists speculate that life on our planet may have originated in the depths of the ocean, near hydrothermal vents. By analyzing the chemical composition of the rock core, microbiologists hope to uncover the conditions that may have led to the emergence of life and the depths at which it transpired.
“This drill hole represents a vital reference point for scientists across multiple disciplines,” a team member stated. “While a single sample cannot provide comprehensive information about the complex pathways of melt and water migration, it remains a significant achievement in geological research.”
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