Archive for the ‘Geology’ Category

Seismology breaks up with the Richter scale

January 29, 2009

Did you hear the news? Green Gabbro not only has the break-up story but also the one about their falling in love in the first place:

I wince every time I see a newspaper article talking about the Richter scale (here it’s from the New York Times last November). Don’t get me wrong, I love the Richter scale – but I love it like you will always love the ex who taught you how to have a real relationship, even though it didn’t work out in the end. Seismology’s relationship with the Richter scale was deep and meaningful, and they will always think fondly of their time together, but they are no longer right for one another.

Take a look!

Fractofusus misrai 

September 19, 2007

A retired Indian geologist who made an internationally known discovery in the 1960s in Canada, then gave up his career in North America to build a village school in India, has received a rare honour: a 565-million-year-old fossil has been named after him. Canadian Ministers, officials and scientists attended a meeting in Canada’s Portugal Cove South city where two top geologists, Guy Narbonne from Canada and Jim Gehling from Australia, announced the name of one of the many fossils discovered by S.B. Misra in the 1960s.The discovery, the oldest record of multi-cellular life on earth, is now called Fractofusus misrai.

From this report in the Hindu; apparently, Dr. Misra retains the fossils with him. The story of the discovery of these fossils is also interesting:

The place where the discovery was made — jutting into the Atlantic Ocean — is known as Mistaken Point. It was one of the most rugged and remote areas of the peninsula and Canadian and foreign students had declined to map the area.

Prof. W.D. Brueckner, a Swiss geologist who headed the Geology Department at Memorial University, St. John’s, Newfoundland, asked the young man to accept the challenge. The assignment, part of his doctoral thesis, was to prepare a geological map of the area.

Dr. Misra won fame when he published research papers based on the discovery in journals including Nature, the Geological Society of America Bulletin and the journal of the Geological Society of India.

Take a look!

Hat tip: To my wife who brought the news item to my attention.

A few links

September 10, 2007

Happy reading!

How old is the earth?

July 5, 2007

When a number of scientists, in the last decade of the nineteenth century, converged on the discovery of radioactivity, it became clear that the earth had heat sources — in the form of uranium, radium, and the other radioactive metals — which Kelvin had not suspected. More important still, it was discovered that the radioactive elements had precise halflives, so that the age of a mineral could be exactly dated by measuring the proportion of isotopes it contained. In effect, radioactivity offered the earth-clock that scientists had long been searching for.

That clock enabled Clair Patterson, an American geochemist who died as recently as 1995, to solve the mystery that had baffled Aristotle and Newton and Kelvin. By analyzing samples of terrestrial lead, and comparing them to lead from the great meteorite that created the Meteor Crater in Arizona, Patterson concluded that the Earth was formed 4.55 billion years ago. The immensity of the figure is staggering, not least because it renders absurd all anthropocentric accounts of the Creation and the universe. But if “A Natural History of Time” teaches one lesson, it is that any attempt to shortcircuit the truth, in the name of a consoling myth, is destined to fail. Worse, it is an insult to human dignity. If there is anything miraculous about mankind, it is not our Scriptures, but our ability to read the text of the world. In a time when obscurantism speaks louder and louder, Mr. Richet reminds us that the truth, if anything, is what will set us free.

From this review by Adam Kirsch of Pascal Richet’s A natural history of time. Via A&L Daily.

Amazing rock solidification structures

June 26, 2007

Aardvarchaeology has some amazing pictures of Napoleonite rocks (etched by ice?); I do not know what my solidification friends call the process of the formation of this structure. But it sure is very interesting. Take a look!

The materials science of earth

May 15, 2007

Today I heard Prof. Steven D Jacobsen on Hydrogen related defects in mantle mineralogy: Oceans in the Earth’s interior? The basic question that he addressed is as follows: Is it possible that the minerals in the earth’s mantle, by virtue of their being at high temperatures and pressures, store water. The answer is that the transition region in earth’s mantle (from 410 kms till 660 kms) can in principle store 2-3 wt. % of water.

In reaching these conclusions, he brought together several interesting materials aspects to the problem. They varied from the physical chemistry of hydrogen under high temperatures and pressures, to high pressure-high temperature infra red spectroscopy and neutron diffraction of silicate minerals, to charge neutrality induced point defects in spinels which lead to changes in elastic properties of these minerals, to crystal growth under high pressure-high temperature conditions.

His talk also showed what a live, heaving mass the earth is. For example, how do we know that the transition region of the earth’s mantle begins at the 410th km? Because, during earthquakes, the shear waves that are generated bounce off from these transition layers. Further, after earthquakes, apparently, the earth vibrates like a bell, the normal modes of which can be measured in the laboratory.

Finally, from a materials point of view, it was also very interesting to see that the conditions at the earth’s mantle a few hundred kilometres from the surface could be simulated so well using a diamond anvil cell  (to pressurise) and laser (to heat); and, the resulting phase transitions could be studied in situ using spectroscopic and diffraction techniques, while the microstructure can then be analyzed using TEM.

A nice talk, and a very interesting field! For those of you who are interested in learning more about this area, his home page has several pointers; for those of you at Northwestern, he is also planning a course on the subject. Have fun!