Is there a link between dinosaurs' extinction and this Martian volcano?
Martian volcanologists now have something else to brag about, besides a cool-sounding job title: They think they鈥檝e nailed down the timeline of Mars鈥檚 Arsia Mons volcano.
The southernmost of a volcanic trio making up the colossal Tharsis Montes feature, Arsia Mons鈥檚 giant caldera could swallow up all the water in Lake Huron and still have room for more. Fortunately for the Curiosity rover, the mountain is extinct today, but that wasn鈥檛 always the case. Eruptions probably peaked while the Stegosaurus roamed the earth, and likely bit the dust along with the Triceratops, according to NASA scientists.
鈥淲e estimate that the peak activity for the volcanic field at the summit of Arsia Mons probably occurred approximately 150 million years ago 鈥� the late Jurassic period on Earth 鈥� and then ,鈥� said聽Jacob Richardson, a postdoctoral researcher at NASA鈥檚 Goddard Space Flight Center,聽in a press release.
Dr. Richardson, of course, refers to the non-avian dinosaurs such as Tyrannosaurus, as the avian branch of the dinosaur family is .
But any apparent correlation is purely a temporal coincidence, as even the most astronomically-inclined dinosaur would have been hard-pressed to detect a sign of the eruptions from Earth. By Terran聽standards, Arsia Mons's activity was quiet and rare.
At its peak, the Arsia Mons鈥檚 caldera probably oozed up to two cubic miles of magma every million years, gradually building up the volcano layer by layer.
鈥淭hink of it like a slow, leaky faucet of magma,鈥� said Richardson. 鈥淎rsia Mons was creating about one volcanic vent every 1 to 3 million years at the peak, compared to one every 10,000 years or so in similar regions on Earth.鈥�
Today, the Mars Reconnaissance Orbiter can spy with its mighty eye 29 volcanic vents in the caldera, and the team started by using that data to map the boundaries of the lava flows, and determine who was on top of whom.
The usual geologic dating tricks don鈥檛 work without direct access to the rocks in question, so the researchers had to get creative to figure out how old each flow was, just from looking at the orbiter鈥檚 pictures.
By counting the number of craters over a certain size, the volcanologists were able to figure out the ages of the flows. Older ones have had longer to get bombarded with space rocks while younger ones feature relatively few pockmarks.
Richardson and his colleagues at the University of South Florida then developed a computer simulation to parse through all the data and reconstruct a timeline for the volcano鈥檚 life, which they suggest can provide insight into the geology and history of Mars.
鈥淎 major goal of the Mars volcanology community is to understand the anatomy and life cycle of the planet鈥檚 volcanoes. Mars鈥� volcanoes show evidence for activity over a larger time span than those on Earth, but their histories of magma production might be quite different,鈥� Jacob Bleacher, a planetary geologist at Goddard and a co-author on the study, said in the press release.聽鈥淭his study gives us another clue about how activity at Arsia Mons tailed off and the huge volcano became quiet.鈥�
When compared with Earth, many have a tendency to think of Mars as a dead world ( in that department), but the results of this study serve as a reminder that the active histories of both planets overlap significantly.
As Richardson points out, 鈥淚t鈥檚 possible, though, that the last volcanic vent or two might have been active in the past 50 million years, which is very recent in geological terms.鈥�
