Amazing stuff!
Unfortunately, it appears neither the King Abdullah University nor the Helmholtz Centre for Ocean Research posted any news release on this discovery!
"The Atlantic Ocean’s Balerion Lava Field doesn’t fit any established model of volcanic eruptions"
"A glassy swath of lava discovered on the floor of the Atlantic Ocean doesn’t fit any existing explanation for how volcanoes form. Named the Balerion Lava Field after the gargantuan black dragon from the TV series Game of Thrones, it may represent a previously unrecognized form of volcanism lurking across Earth’s still mostly unexplored sea floor. ...
But the Balerion Lava Field—located in the northwestern Atlantic far from any subduction zone, midocean ridge, or known hot spot—fits none of these categories. ..."
From the abstract:
"The abyssal plains cover more than half of Earth’s surface and are generally regarded as volcanically and hydrothermally inactive environments that progressively accumulate pelagic sediments with age. This assumption is the basis for models on e.g., oceanic crust evolution, chemical budgets of the deep ocean floor, and the distribution of hard-substrate benthic habitats.
Here, we present high-resolution acoustic data, seafloor observations, and sample characteristics from the NW Atlantic abyssal seafloor that reveal 360 km2 of young (<50 ka) volcanism on 20 Ma oceanic crust.
These Balerion Lava Fields do not display a significant bathymetric expression and are only detectable from the surface by a stronger acoustic backscatter, pointing to limited sedimentation.
Geochemistry of the lavas reveals that the lavas are Si-saturated basaltic andesites with low Ca and Fe at relatively high Mg contents. Whole rock trace element and elevated Ni, low Ca/Fe olivine chemistry signatures resemble those of Hawaiian samples from Koʻolau and Mauna Loa that have been linked to pyroxenite-bearing mantle sources.
Isotopic compositions are close to the PREMA mantle domain. Small (<1 mm), skeletal phenocrysts suggest rapid crystal growth and ascent of low-viscosity, possibly superheated melts with little or no crustal storage.
Regional bathymetry and tectonic structure are consistent with normal 20 Ma seafloor subsidence and deformation, providing no evidence for anomalous lithospheric thinning, intraplate extension, or a mantle thermal anomaly.
Instead, the geochemical characteristics point to magma generation at >2 GPa from a pyroxenite-rich source within the asthenosphere [cf. 4].
We propose that the Balerion volcanism reflects melting of anomalous volumes of recycled oceanic crust, rising in the convecting upper mantle. Such processes may occur widely beneath oceanic plates, representing a form of intraplate magmatism independent of both plate tectonics and mantle plumes."
Hidden, young lavas on the 20 Ma old abyssal plain: A new form of oceanic intraplate volcanism
A crystal of olivine in a sample of seafloor lava that resembled a dragon prompted researchers to name the eruptive flow Balerion, after a Game of Thrones dragon
No comments:
Post a Comment