Many scientists thought Venus had been geologically dormant for past half-billion years
Thomson Reuters · Posted: Jul 21, 2020
Two coronae, which are ring-like structures formed when hot material from deep inside the planet rises through the mantle and erupts through the crust, are observed on the surface of Venus in a 3D rendering provided to Reuters on July 20. (Laurent Montesi/University of Maryland/Handout via REUTERS )
Scientists have identified 37 volcanic structures on Venus that appear to be recently active — and probably still are — painting the picture of a geologically dynamic planet and not a dormant world, as was previously thought.
The research focused on ring-like structures called coronae, caused by an upwelling of hot rock from deep within the planet’s interior, and provided compelling evidence of widespread recent tectonic and magma activity on Venus’s surface, researchers said on Monday.
Many scientists had long thought that Venus, lacking the plate tectonics that gradually reshape Earth’s surface, had essentially been dormant geologically for the past half-billion years.
“Our work shows that some of that interior heat is still able to reach the surface even today. Venus is clearly not so geologically dead or dormant as previously thought,” said Earth and planetary scientist Anna Gülcher of the Institute of Geophysics in Zurich, lead author of the research published in the journal Nature Geoscience.
The researchers determined the type of geological features that could exist only in a recently active corona — a telltale trench surrounding the structure. Then they scoured radar images of Venus from NASA’s Magellan spacecraft in the 1990s to find coronae that fit the bill.
Of 133 coronae examined, 37 appear to have been active in the past two to three million years, a blink of an eye in geological time.
“In my opinion, many of these structures are indeed active today,” said University of Maryland geophysicist and study co-author Laurent Montesi.
This hemispheric view of Venus is based on radar investigations from the 1990-1994 Magellan mission. Many scientists had long thought the planet, lacking the plate tectonics that gradually reshape Earth’s surface, had essentially been dormant geologically for the past half-billion years. (NASA/JPL/USGS/Handout via REUTERS)
Coronae are essentially fields of lava flows and major faults spanning a large circular area. Many of the 37 reside within a gigantic ring in the planet’s southern hemisphere, including a colossal corona called Artemis 2,100 kilometres in diameter.
Venus, Earth’s closest and just slightly smaller planetary neighbour, is covered by clouds of sulphuric acid and has surface temperatures hot enough to melt lead.