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Molten Rock Layer

11 February 2023
Geology, Plate Tectonics

The headline reads, scientists detect a molten rock layer hidden beneath earth’s tectonic plates – see https://phys.org/news/2023-02-scientists-molten-layer-hidden-earth.html … I wonder why they said ‘tectonic plates’ rather than crust? However, the reason is explained in the first couple of paragraphs. The idea is to settle a long  standing debate on how tectonic plates move. We are then told it is partly molten rock. Not entirely viscosity. In fact, the authors would appear to favour the convection theory.

The article is published in Nature Geoscience and will therefore be taken seriously by geologists [February 2023]. The molten layer, they say, is about 100 miles below the surface, part of the asthenosphere. It sits directly underneath earth’s hypothetical plates – at the margin with the upper Mantle. The asthenosphere is important as far as Plate Tectonics are concerned as it forms a relatively soft boundary  that allows the plates to move, albeit gradually. Very lsowly in fact. The reason why it is soft is another subject of debate. There are a lot of geological uncertainties  which the public don’t get to know about. Why they don’t say this openly is a mystery. Surely they can’t be afraid it will give sustenance to the Biblical flood types.

The new study shows that melt, itself, does not appear to influence the flow of Mantle rock. It is in fact a minor effect, we are told. It is the convection of heat and rock in the Mantle that influences motion of the plates. The researchers compiled seismic images from seismic activity around the world in order to create a model  of the asthenosphere. They have composed the modelled map with seismic and tectonic movements, and found no correlation – in spite of the molten layer existing over half of the globe. See https://doi.org/10.1038/s41561-022-01116-9

See also https://www.dailymail.co.uk/sciencetech/article-11723215/ … new layer under the earth, the molten rock layer covers 44 per cent of our planet. However, even when the molten layer is most obvious its effects on Mantle flow is minor. Extremely minor. They then fall back to convection currents in the Mantel below the crust. Is this evidence of plate tectonics or is it telling us something else?

This leads into the next link at https://phys.org/news/2023-02-magma-unexpected-route-beneath-volcanoes.html … magma following an unexpected route beneath volcanoes has been observed by researchers. The findings were based on a proposed tectonic plate boundary in the Caribbean. The research is thought to help understand volcanic eruptions – why some are more active than others. It is poorly understood, we are told, how magma forms underground, and what controls the position of volcanoes at the surface. They now claim it is not subduction, or the plates moving across the descending plate at the subduction boundary, but a combination of both processes, at work at plate boundaries. Interesting read, the energy of seismic waves dissipate in hot and molten rock.

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