Amazing stuff!
"... In 2023, scientists drilled more than a kilomter, not to the mantle directly, but into the undersea mountain Atlantis Massif in the middle of the North Atlantic Ocean. ...
“Our study begins to look at the composition of the mantle by documenting the mineralogy of the recovered rocks, as well as their chemical makeup. ..."
"... The nearly continuous 1,268 metres of mantle rock was recovered from a “tectonic window,” a section of the seabed where rocks from the mantle were exposed along the Mid-Atlantic Ridge ...
The study also provides initial results on how olivine, an abundant mineral in mantle rocks, reacts with seawater, leading to a series of chemical reactions that produce hydrogen and other molecules that can fuel life. ..."
From the editor's summary and abstract:
"Editor’s summary
The mantle of the Earth is hard to sample, with most of our direct information about it coming from rocks dredged off the ocean floor or from ancient mantle thrust up onto the crust in the form of ophiolites. Lissenberg et al. present the shipboard observations from the International Ocean Drilling Project Expedition 399, which drilled 1268 meters deep into the mantle under the seafloor ... The rock section was recovered from a hydrothermally active region near the mid-Atlantic ridge and should help us better understand the chemistry of mantle rocks shaped by the nearby magma extraction process that forms new ocean crust. ...
Abstract
The upper mantle is critical for our understanding of terrestrial magmatism, crust formation, and element cycling between Earth’s solid interior, hydrosphere, atmosphere, and biosphere. Mantle composition and evolution have been primarily inferred by surface sampling and indirect methods. We recovered a long (1268-meter) section of serpentinized abyssal mantle peridotite interleaved with thin gabbroic intrusions. We find depleted compositions with notable variations in mantle mineralogy controlled by melt flow. Dunite zones have predominantly intermediate dips, in contrast to the originally steep mantle fabrics, indicative of oblique melt transport. Extensive hydrothermal fluid-rock interaction is recorded across the full depth of the core and is overprinted by oxidation in the upper 200 meters. Alteration patterns are consistent with vent fluid composition in the nearby Lost City hydrothermal field."
Record-breaking recovery of rocks that originated in Earth’s mantle could reveal secrets of planet’s history (original news release)
A long section of serpentinized depleted mantle peridotite (no public access)
The researchers say the rocks recovered from the mantle bear a closer resemblance to those that were present on early Earth rather than the more common rocks that make up our continents today.
Scientists analyzing the cores.
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