Young lava flows detected by ESA’s Venus Express spacecraft are just few years old, according to new research from Universities Space Research Association (USRA).
An artist’s impression of a volcano erupting on Venus. Image credit: ESA / AOES Medialab.
In 2010, Venus Express scientists reported that the infrared radiation coming from three regions on Earth’s neighbor planet was different to that from the surrounding terrain.
The researchers interpreted this as coming from relatively fresh lava flows.
They suggested that some lava flows were younger than 2.5 million years, and possibly even younger than 250,000 years, but they could not establish whether there is still active volcanism on the planet.
“The crust of Venus consists mostly of basaltic rock, which is in contact with its hot caustic atmosphere,” explained Dr. Justin Filiberto, a USRA staff scientist at the Lunar and Planetary Institute, and his colleagues.
“Chemical reactions between Venus’ basaltic crust and its atmosphere, i.e., weathering, modify the surface’s mineralogy and composition and affect its visible to near-infrared spectral characteristics.”
“Without liquid water, weathering, based on experimental and modeling work, is suggested to be geologically slow and includes mainly oxidation reactions that produce coatings of hematite and/or magnetite on surfaces of iron-bearing mineral grains.”
“However, the rates of oxidation on Venus, and how these weathering results affect reflectance spectra, are not well understood and are needed to constrain the ages of lava flows measured by the Venus Express mission.”
This figure shows the volcanic peak Idunn Mons in the Imdr Regio area of Venus. The topography derives from data obtained by NASA’s Magellan spacecraft, with a vertical exageration of 30 times. Radar data (in brown) from Magellan has been draped on top of the topographic data. Bright areas are rough or have steep slopes. Dark areas are smooth. The colored overlay shows the heat patterns derived from surface brightness data collected by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) aboard ESA’s Venus Express spacecraft. Temperature variations due to topography were removed. The brightness signals the composition of the minerals that have been changed due to lava flow. Red-orange is the warmest area and purple is the coolest. The warmest area is situated on the summit, which stands about 2.5 km above the plains, and on the bright flows that originate there. Idunn Mons has a diameter of about 200 km. The VIRTIS data was collected from May 2006 to the end of 2007. Image credit: ESA / NASA / JPL.
Dr. Filiberto and co-authors recreated Venus’ caustic atmosphere in the lab to investigate how the observed Venusian minerals react and change over time.
Their experimental results showed that olivine, an abundant mineral in basalt, reacts rapidly with the atmosphere and within weeks becomes coated with magnetite and hematite.
They further found that the Venus Express observations of this change in mineralogy would only take a few years to occur.
The results suggest that lava flows on Venus are very young, which in turn would imply that the planet does indeed have active volcanoes.
“This active volcanism is consistent with episodic spikes of sulfur dioxide in the atmosphere measured by both NASA’s Pioneer Venus Orbiter and ESA’s Venus Express, which could have been produced by the same eruptions that formed the young lava flows,” the study authors said.
The study was published in the journal Science Advances.
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Justin Filiberto et al. 2020. Present-day volcanism on Venus as evidenced from weathering rates of olivine. Science Advances 6 (1): eaax7445; doi: 10.1126/sciadv.aax7445
