SciTech Chronicles. . . . . . . . .Mar 26th, 2025
#xenoliths #volatiles #subduction #models #spike #glycans #receptor #low-mutation ##Yellowknife #linear #dodecane #SAM #lipids #Mesoscale #signature #transport #photolysis #replenishment #size #thickness
In a geologic triumph, scientists drill a window into Earth’s mantle
The #mantle isn’t a complete unknown. Occasionally, volcanic eruptions spew out bits of it — chunks of greenish #peridotite, the type of rock that dominates the upper mantle, embedded in basalt rock. But these samples, called mantle #xenoliths, have their limits, because they are often chewed up and weathered from their trip to the surface.
There are also #ophiolites, sheets of oceanic crust tinged with some of the upper mantle that were uplifted and plastered onto the land. But they too have been altered by the trip.
What scientists have long craved was a drilled sample of mantle rock. #Project #Mohole, a famous ocean expedition, set out to drill through the thinner crust on the ocean floor to reach the mantle in 1961 but failed.
Portions of the ocean floor where the mantle is closer to the surface seemed like an opportunity to take a sample without the technical difficulties of drilling through miles of crust. That’s where the scientists aboard the }#JOIDES #Resolution set their sights for one of the vessel’s last missions before its scheduled retirement in fiscal year 2024.
The team departed Ponta Delgada in Portugal’s Azores Islands in April and headed to the Atlantis Massif, an underwater mountain about the size of Mount Rainier. Its primary mission wasn’t to drill the deepest hole yet in mantle rock, but to sample those rocks for clues about how, in the absence of life on infant Earth, small organic molecules might have formed as rocks reacted with water.
“This could be a way that you go from just having basically water and rock,” said Susan Lang, the co-chief scientist of the expedition and a scientist at the Woods Hole Oceanographic Institution. “That produces hydrogen, [and] that hydrogen is a really big fuel to things like the formation of smaller organic molecules, and that can then combine with other organic molecules and lead to early life.”
https://www.washingtonpost.com/science/2023/06/06/drill-earth-mantle-rocks/
