Reporter doing a phone interview: “Please slow down, professor. You’ve been researching this topic for a decade. I’ve been researching it since lunchtime.”
Source via RealClimate
Saturday, January 15, 2011
Monday, January 10, 2011
Zircon Zapping And Antarctica Fieldwork
New York Times Scientist At Work Blog features a geologist this time.
John Goodge, a professor of geological sciences at the University of Minnesota-Duluth writes about his research and field work in Antarctica along with a good explanation of the various zircon dating methods and the instruments involved in this sophisticated geochemical analysis.
..the A.N.U. has been building a special class of ion probes since the 1980s called Shrimp, which stands for sensitive high-resolution ion microprobe. The name Shrimp belies their actual size. These instruments cover a floor space of about 13 feet by 20 feet. It is by virtue of their size, the so-called turning radius of the mass spectrometer’s magnet, that they are so powerful in dating zircons of only a few tens of microns in size by the U-Pb method. In other words, analyzing something very small sometimes takes something very big.
Not quite the Large Hadron Collider... but impressive nonetheless.
The aim is to reconstruct the evolution of Antarctica crust and for that, dating the rocks accurately is essential. Not all rock samples are exposed as outcrop.. the scientists are relying on rock fragments eroded by glaciers and dumped in moraine deposits to sample pieces of crust hidden under ice.
Good stuff.
John Goodge, a professor of geological sciences at the University of Minnesota-Duluth writes about his research and field work in Antarctica along with a good explanation of the various zircon dating methods and the instruments involved in this sophisticated geochemical analysis.
..the A.N.U. has been building a special class of ion probes since the 1980s called Shrimp, which stands for sensitive high-resolution ion microprobe. The name Shrimp belies their actual size. These instruments cover a floor space of about 13 feet by 20 feet. It is by virtue of their size, the so-called turning radius of the mass spectrometer’s magnet, that they are so powerful in dating zircons of only a few tens of microns in size by the U-Pb method. In other words, analyzing something very small sometimes takes something very big.
Not quite the Large Hadron Collider... but impressive nonetheless.
The aim is to reconstruct the evolution of Antarctica crust and for that, dating the rocks accurately is essential. Not all rock samples are exposed as outcrop.. the scientists are relying on rock fragments eroded by glaciers and dumped in moraine deposits to sample pieces of crust hidden under ice.
Good stuff.
Friday, January 7, 2011
Review Article On The Origin Of Mountains
Simon Lamb and Anthony Watts have published a review article on the Origin of Mountains in a recent issue of Current Science. This volume has a special section: Perspectives on Earth Sciences 2010.
The article discusses at length the basic principles of mountain building.. isostacy, crust mantle density and thickness contrasts, horizontal forces, lithosphere and asthenosphere strength and flow characteristics along with examples from the Andes and Himalayas and plenty of neatly annotated figures.
There is a nice symmetry to the way it ends, suggesting that the nuclei of stable continental crust are forged in the weak interior of great mountains:
Graduate students and educators should find this a very good resource to brush up on the fundamentals.
The article discusses at length the basic principles of mountain building.. isostacy, crust mantle density and thickness contrasts, horizontal forces, lithosphere and asthenosphere strength and flow characteristics along with examples from the Andes and Himalayas and plenty of neatly annotated figures.
There is a nice symmetry to the way it ends, suggesting that the nuclei of stable continental crust are forged in the weak interior of great mountains:
An intriguing final insight of all this is that the central highly deformed parts of mountain belts, by being such weak and mobile parts of the Earth, may be the places where the strong cratonic cores of the continents were first formed, comprising what are today the most stable parts of the dry land we live on. This is because the process of mountain building, by squeezing both the crust and mantle parts of the lithosphere, creates a thick lithosphere.
Over time, as geotherms relax and the crust heats up as a result of the increased radiogenic heat generation in the thickened crust, granulite grade metamorphism will occur, eventually dehydrating and further strengthening the crust. If, at some later stage, the crust in this thick lithosphere is eroded back down to its original thickness of around 30–40 km, as isostasy would predict, the land surface will return to around sea level, but with the deep crustal levels of granulite grade metamorphic basement now exposed at the surface. So, as has been long suspected by geologists, mountain building, although occurring in only a small fraction of the surface area of the continents at any one time, might have shaped most of the Earth’s continental crust.
Graduate students and educators should find this a very good resource to brush up on the fundamentals.
Thursday, January 6, 2011
Geologists Entering New Legal Territory?
Stephen Testa writes in Earth Magazine of some recent legal problems for geologists.
Getting into trouble over "risk management" was something one would associate with dodgy Wall Street high fliers. Now the term seems to be encompassing the grinding of tectonic plates and the health of ecosystems as well with accountability spilling over towards the custodians of scientific data.. geologists are among those on the frontlines of this emerging engagement with society as responsible analyzers of risk.
We live in a litigious society. Engineering and environmental geologists
are no strangers to the legal system. They frequently deal with issues
relating to geologic hazards such as active faults and unstable ground,
the release of contaminants into the environment and numerous other
circumstances. But for the most part, geoscientists tend to avoid legal
battles. Is that changing?
In the last couple of years, several events have brought geologists into
new legal territory. Geologists have recently been accused of
potentially inducing earthquakes, of not predicting natural hazards, of
potentially adversely impacting water quality, of spying and of engaging
in indelicate e-mail discussions and alleged misdealings with climate
change data.
Getting into trouble over "risk management" was something one would associate with dodgy Wall Street high fliers. Now the term seems to be encompassing the grinding of tectonic plates and the health of ecosystems as well with accountability spilling over towards the custodians of scientific data.. geologists are among those on the frontlines of this emerging engagement with society as responsible analyzers of risk.
Tuesday, January 4, 2011
Geology Word Usage Using Google Ngram Viewer
I don't have the answers but I've been having fun with Google Ngram Viewer, a tool that can track the change in frequency of word usage through time.
Google has relied on about 5 million books containing a total of 500 billion words digitized from library collections to come up with a graphical view of word usage changes. The algorithm compares the frequency with which a particular word occurs in these five million books compared to all other words. You can go as far back as 1500 but the more reliable results are from about the 1800's. You can also view the list of books that the word occurs in.
You can find out when a word first came into use, how its popularity waxed and waned through time, and by pairing words with similar meaning or contexts try to figure out why the frequency of that word usage may have changed. That may reflect cultural trends, fashion or maybe new developments in a scientific field, technology or something else.
The tool doesn't offer any explanation why a word has become less or more common.
I plugged in a few geology terms.
Aqueous rock - all the way from 1800.
The word aqueous for describing rock or sediment formed in water was popular in the 1800's, but as science advanced, slowly has given way to more specific terms that describe the conditions in which sediment was deposited.
Peneplain, which describes a low relief surface caused by prolonged weathering. - 1900's onwards
I've added the words landform and geomorphology to see if the decline since the 1940's could be due to less interest over time in studying landforms. You can see though that both landform and geomorphology show a marked increase in usage. Likewise, the terms erosional surface and planation surface do show small but significant increases in use. I think the use of the word surface in isolation and as a suffix to a word that described the process of feature formation, both terrestrial and marine, became somewhat the norm. With a more process oriented approach to describing features, Peneplain may have just become a less fashionable way of describing low relief weathered landforms.
How about the way geology departments are named? 1900 onwards..
You can see that the term Department of Geology is the most common way of naming a geology department. It term show a steady increase through the 1900's with a surge around the mid 1960's, peaking in the 1980's and then declining. That may reflect a smaller number of newer geology departments...?
Accompanying this pattern though are a number of other ways of naming geology departments.. the terms Geology and .. Earth Sciences.. Earth Sciences and... become more common beginning the 1960's. The increase in Geology and... may reflect the hardening of geology specializations like geophysics and geochemistry. Departments acquired multiple specializations with important faculty presiding over their respective domains and hence were named accordingly.
Regarding the term Earth Sciences.. check out the usage of these two terms - interdisciplinary and holistic.
Both show a marked increase beginning the 1960's and point to more collaboration between different fields, an increased awareness of the importance of understanding the interaction of the geosphere with the biosphere and atmosphere, a generally increased tendency to study the bigger picture.. hence more department names reflecting the interdisciplinary nature of their endeavors.
Finally the influence of technological developments - the words maps and mapping - 1900 onwards.
Both show a steady increase through the last century and that does reflect the increased exploration and scrutiny of various aspects of the earth. The term mapping though shows a marked increase in usage through the 1970's.
Two technological developments may have helped. In 1972, the Landsat remote sensing satellite program became operational and began releasing earth images for public consumption, thereby making it easier to map the earth's surface. Satellite imagery is now commonly used for mapping.
And in the mid -late 1980's computer assisted mapping tools like Geographic Information Systems (GIS) software started becoming available resulting in increased access to geographic data and new ways of compiling maps.
So.. plug in your favorite geology term, analyze its rise and demise.. have fun!
...OnPoint Radio has an interesting talk on Google Ngram.
Google has relied on about 5 million books containing a total of 500 billion words digitized from library collections to come up with a graphical view of word usage changes. The algorithm compares the frequency with which a particular word occurs in these five million books compared to all other words. You can go as far back as 1500 but the more reliable results are from about the 1800's. You can also view the list of books that the word occurs in.
You can find out when a word first came into use, how its popularity waxed and waned through time, and by pairing words with similar meaning or contexts try to figure out why the frequency of that word usage may have changed. That may reflect cultural trends, fashion or maybe new developments in a scientific field, technology or something else.
The tool doesn't offer any explanation why a word has become less or more common.
I plugged in a few geology terms.
Aqueous rock - all the way from 1800.
The word aqueous for describing rock or sediment formed in water was popular in the 1800's, but as science advanced, slowly has given way to more specific terms that describe the conditions in which sediment was deposited.
Peneplain, which describes a low relief surface caused by prolonged weathering. - 1900's onwards
I've added the words landform and geomorphology to see if the decline since the 1940's could be due to less interest over time in studying landforms. You can see though that both landform and geomorphology show a marked increase in usage. Likewise, the terms erosional surface and planation surface do show small but significant increases in use. I think the use of the word surface in isolation and as a suffix to a word that described the process of feature formation, both terrestrial and marine, became somewhat the norm. With a more process oriented approach to describing features, Peneplain may have just become a less fashionable way of describing low relief weathered landforms.
How about the way geology departments are named? 1900 onwards..
You can see that the term Department of Geology is the most common way of naming a geology department. It term show a steady increase through the 1900's with a surge around the mid 1960's, peaking in the 1980's and then declining. That may reflect a smaller number of newer geology departments...?
Accompanying this pattern though are a number of other ways of naming geology departments.. the terms Geology and .. Earth Sciences.. Earth Sciences and... become more common beginning the 1960's. The increase in Geology and... may reflect the hardening of geology specializations like geophysics and geochemistry. Departments acquired multiple specializations with important faculty presiding over their respective domains and hence were named accordingly.
Regarding the term Earth Sciences.. check out the usage of these two terms - interdisciplinary and holistic.
Both show a marked increase beginning the 1960's and point to more collaboration between different fields, an increased awareness of the importance of understanding the interaction of the geosphere with the biosphere and atmosphere, a generally increased tendency to study the bigger picture.. hence more department names reflecting the interdisciplinary nature of their endeavors.
Finally the influence of technological developments - the words maps and mapping - 1900 onwards.
Both show a steady increase through the last century and that does reflect the increased exploration and scrutiny of various aspects of the earth. The term mapping though shows a marked increase in usage through the 1970's.
Two technological developments may have helped. In 1972, the Landsat remote sensing satellite program became operational and began releasing earth images for public consumption, thereby making it easier to map the earth's surface. Satellite imagery is now commonly used for mapping.
And in the mid -late 1980's computer assisted mapping tools like Geographic Information Systems (GIS) software started becoming available resulting in increased access to geographic data and new ways of compiling maps.
So.. plug in your favorite geology term, analyze its rise and demise.. have fun!
...OnPoint Radio has an interesting talk on Google Ngram.
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