Friday Headlines, December 13, 2013
THE LATEST IN THE GEOSCIENCES
A freshwater lake on Mars
Did volcanoes cause the huge extinction 250 million years ago?
Researchers at the California Institute of Technology have discovered that on part of the Gale Crater on Mars, where the Curiosity rover has been roving for the past year, once contained a very nearly freshwater lake. This lake existed about 3.7 billion years ago, about the same time that the earliest physical evidence of life on Earth appears.
The inferences are based on the study of mudstones that were once the sediments on the bottom of the lake. The specific types of clay minerals that were present indicate that the lake was freshwater and contained many of the key chemical ingredients for life.
Such an environment would be suitable for bacterial life, leading some to propose that life might have existed on Mars at that time, too. As yet, however, we have no definitive proof that life has ever been present on Mars.
This is a two-part headline.
The science part is interesting. About 30 million years ago, enormous volcanoes in the region of central Utah and Colorado, were exploding enthusiastically like Mount Saint Helens did in May of 1980. Processes of erosion have all but erased any evidence of these volcanoes. Only ashes and other pyroclastic debris (things blown out of volcanoes) remain as clues to their former presence.
Then there’s the did-I-hear-that-right part of this headline. I admit that I laughed out loud when I read this in the press release.
Mount Saint Helens is a stratovolcano, not a ‘straddle’ volcano. Obviously, whomever wrote the article mis-heard the scientists as they explained the significance of their findings.
This kind of error should have been caught. But it wasn’t, because the press release was probably published without being reviewed by the geologists cited in it. It happens.
What does this mean?
Press releases are helpful to find interesting information, but do so with caution, because sometimes mistakes creep in.
Many people think that the extinction of the dinosaurs 65 million years ago is the biggest extinction that the Earth has ever seen. This is probably because it gets all the press. I mean… DINOSAURS!
But the extinction event that killed off the dinosaurs is small peanuts compared to one that happened about 250 million years ago. This one occurred at the boundary between the Permian and Triassic periods. This event killed off 95% of all animals living in the ocean, and took out about 70% of life on land.
The thing geologists and paleontologists want to know is, what caused such a huge extinction?
What we do know is that at about that time, there were massive volcanic eruptions in what is now Siberia. The lava that erupted at that time would have covered the United States a mile deep.
Such an eruption would be expected to have severe climatic effects. We know that much smaller eruptions on the modern Earth have caused measurable global climate changes.
The challenge is determining whether the eruptions happened before or after the extinction. If the eruptions followed the extinction event, surely they couldn’t have been the cause.
New research conducted by researchers at MIT shows that the eruptions did precede the extinction. This means that the eruptions could have led to the extinction event.