March 2005

According to two UC Berkeley physicists (that’s right, not paleontologists) who have analyzed fossil records going back to the Pre-Cambrian, they have concluded that extinctions on Earth happen with startling regularity. According to this article in the San Francisco Chronicle, the cycles are so clear that the evidence “simply jumps out of the data,” said James Kirchner, a professor of earth and planetary sciences on the Berkeley campus who was not involved in the research but who has written a commentary on the report that is also appearing in Nature today.

Edit by Dave (03/13) - Here is a link to a news release from Lawrence Berkeley Laboratories.

In a story of public interest in geology driven by entertainment, this BBC news report focuses on a report issued from a group of British geologists (timed to coincide with the release of a television drama about the same thing) is warning that the risk posed to civilization by a so called “super-volcano” is 5-10 times more likely than that of an asteroid impact. The authors want to highlight the issue, which they feel is being ignored by governments. They emphasise that while catastrophic eruptions of this kind are rare in terms of a human lifetime, they are surprisingly common on a geological scale. The effects, say the authors, “could be sufficiently severe to threaten the fabric of civilisation” - putting events such as the Asian tsunami into the shade.

I picked this up via UC Davis’ Geology News site. Researchers are reconsidering how the Barringer Meteor Crater in Arizona may have formed. A long standing mystery revolving around the crater is that there have been no signs of significant amounts of melted minerals. A new study to be published in Nature says, “The high-velocity collision should have released so much heat that the iron-rich impacting rock itself, or at least part of it, should have melted in a flash. But no substantial signs of melted mineral have ever been found there. The reason, according to a new study: the rock was merely the largest chunk from a space bruiser that probably measured 42 meters (136 feet) across.”

Tuesdays small eruption by Mount St. Helens surprised scientists, according to an article by the Statesmen Journal. Scientists did not know what caused the larger-than-normal plume, but said that in the hours preceding the incident, the seismograph readings had changed. Although the peaks, indicating the strength of each seismic burst, were not higher than normal, the line separating them had become “noisier,” Major said. What scientists do know is that the plume rose very rapidly and much higher than in previous months. That indicates that there was an explosive element inside, rather than just a collapse of the crater’s roof. The Cascades Volcano Observatory also has some great pictures from Tuesday’s eruption.

A new study in this month’s journal of Geology shows that people who live downwind of the Kilauea Volcano could have an increased risk of respiratory or cardiac ailments caused by exposure to high levels of sulfur dioxide and aerosol particulates.