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Scientists Discover Volcanoes on Venus Are Still Active
A new study identified 37 recently active volcanic structures on Venus. The study provides some of the best evidence yet that Venus is still a geologically active planet. A research paper on the work, which was conducted by researchers at the University of Maryland and the Institute of Geophysics at ETH Zurich, Switzerland, was published in the journal Nature Geoscience on July 20, 2020.
[...] Scientists have known for some time that Venus has a younger surface than planets like Mars and Mercury, which have cold interiors. Evidence of a warm interior and geologic activity dots the surface of the planet in the form of ring-like structures known as coronae, which form when plumes of hot material deep inside the planet rise through the mantle layer and crust. This is similar to the way mantle plumes formed the volcanic Hawaiian Islands.
But it was thought that the coronae on Venus were probably signs of ancient activity, and that Venus had cooled enough to slow geological activity in the planet's interior and harden the crust so much that any warm material from deep inside would not be able to puncture through. In addition, the exact processes by which mantle plumes formed coronae on Venus and the reasons for variation among coronae have been matters for debate.
Also at EarthSky.
Corona structures driven by plume–lithosphere interactions and evidence for ongoing plume activity on Venus (DOI: 10.1038/s41561-020-0606-1) (DX)
Journal Reference:
Anna J. P. Gülcher, Taras V. Gerya, Laurent G. J. Montési, et al. Corona structures driven by plume–lithosphere interactions and evidence for ongoing plume activity on Venus, Nature Geoscience (DOI: 10.1038/s41561-020-0606-1)
(Score: 3, Informative) by Kitsune008 on Tuesday July 21 2020, @02:57PM
A REALLY simplified answer would be: It's complicated.
Okay, first off, I do not doubt your intelligence or ability to reason...your comments have demonstrated you have both.
An adequate answer would involve way more typing than I am willing to do, and you would be scrolling forever to read it.
Wikipedia has a decent version, but you have to follow some of the citations. :-)
So I'm going with a more 'real simple' version.
For a long time there was debate about Venus having a liquid core, if there was a mantle...how thick, thick or thin crust, plate tectonics or not.
All of these were related to the discussion of what happened to Venus' magnetic field, and when.(We knew that Venus used to be Earth-like w/ liquid water, so therefore it must have had a 'dynamo' producing a magnetic shield, right?[newer debate])
Which leads to the different models we developed to explained observations:
Venus has no plate tectonics, at least not for several billion years. Volcanism on Venus will be different than on Earth.
There has been no indication of recent active volcanoes on Venus.
a) Venus rotates to slow to create magnetic shield(recent models/calculations seem to discount this), but still has a solid core and liquid mantle
b) Venus lost it's solid core(it melted), and has a liquid core/mantle with a thick crust
c) various versions in between
The cooling referred to has put more weight on b), due to lack of recent signs of volcanism.
The crust radiates heat quick enough that currents in the liquid keep a solid core from forming, and a thicker crust develops.
With no plate tectonics, and a thicker crust, volcanism doesn't stand a chance.
This changes that discussion. Back to the drawing board. :-)