Tuesday, July 31, 2012

Hyperspectral Mapping Of The Geology Of Afghanistan

This post submitted to the Accretionary Wedge # 48 hosted by Earth-like Planet. The theme is "Geoscience and Technology" and this post is on the use of multi and hyperspectral remote sensing for geological mapping.

Coinciding with the 40th anniversary of the Landsat series of remote sensing satellites, two maps of the surface distribution of several distinctive minerals covering a large portion of Afghanistan has been released by the USGS.

 Source: USGS Pub A

These maps have been prepared by processing the reflectance properties of surface materials captured by sensors aboard a plane. Conventional satellite mapping like that prepared from Landsat data does the same thing but it generally captures less information. For example, most conventional commercial satellites will capture reflected energy in the visible and the near infra red portion of the spectrum in 4 - 7 bands.

This type of remote sensing of the reflected and emitted energy from surface material is termed multispectral sensing. Recently, new satellites have started capturing hyperspectral data. Here, the energy from the visible to infrared spectrum is collected at very narrow intervals or channels. For example, NASA's Hyperion sensor aboard the EO-1 satellite is capable of collecting spectral information in 220 spectral bands from between the 0.4 to 2.5 ┬Ám (micrometer) bandwidth with a 30-meter ground resolution.

Thursday, July 26, 2012

Battling For The One True History Of Israel

The Chronicle of Higher Education has a fascinating article on several new archaeological finds in Israel. There is serious scholarship addressing these finds and reasonable scientists have different opinions on the significance of ruins and artifacts, particularly on the correspondence of archaeological finds and biblical stories. On the other hand there is some apprehension that these findings are being used by some to push forward a nationalistic version of the history of Israel.

The wild card and one that may be having a damaging impact on the field of archaeology is the recent interest shown by cable TV and film producers:

In the old days, scholars could spend years excavating a site, and then more years, perhaps decades, marshaling material and publishing their conclusions.

In recent years, a new hunger for publicity and acclaim has changed all that. As the cost of excavations and scholarship has risen, archaeologists have turned to private sponsors and commercial organizations to underwrite their expeditions. Publicity has become a key tool for raising money. With the proliferation of cable TV, channels like National Geographic and Discovery, and then independent film producers, were able to provide huge injections of cash in return for exclusive access and production rights to the most camera-friendly expeditions. After such heavy investment, the producers expect discoveries that would create headlines and attract large audiences.

In the past decade, a steady stream of spectacular discoveries linked to well-known biblical stories has come from a mixture of outright charlatans, religious foundations, highly regarded mainstream archaeologists, and even the Israel Antiquities Authority, an official government agency that oversees all archaeological work in Israel. Some of the announcements read like a modern-day search for holy relics.

Suddenly, every archaeologist is being compared with Indiana Jones, and filmed in what appear to be similar settings.

Saturday, July 21, 2012

Creationism And Fused Chromosomes

I used to avidly follow the evolution creationism debates on the internet. The beginning of my interest was the flurry of rebuttals to Michael Behe's book Darwin's Black Box which were put up on Boston Review. It was a great learning experience as biologists picked apart the concept of intelligent design and "irreducible complexity".

That tradition of battling creationists by providing clear explanations of biological phenomena continues with science writer Carl Zimmer explaining how the fusion of chromosomes can explain the difference in the chromosome number between our closest relatives and humans. Gorillas and chimpanzees have 24 pairs of chromosomes while humans have 23 pairs. John Hawks pitches in and gives an insight into the relationship between large genetic changes and the origin of new species.

I am always completely befuddled by the creationist response. I mean who are the creationists really addressing?  Their arguments against evolution are usually poor and not backed by evidence and their alternative explanations for the origin of complexity and diversity like Michael Behe's idea of a pre-formed genome border on the ridiculous. Even they must know that they will never win over biologists and well.. people with the ability to think for themselves..:)

My take is that creationists are not so much trying to convert people to the idea of creationism as much as trying to keep their flock from rejecting God and migrating to the side of rationality. Their enterprise of rejecting evolution and providing counter "explanations" rely on the vast majority of people with faith who already reject evolution only reading creationist literature. You could argue that with the internet it is so easy to find and read arguments put forward by scientists. That is true, but it is also true that people with strong convictions generally seek out conforming opinions and then stick to their own community. I doubt if the vast majority of followers of major creationist websites take the trouble of reading the criticisms of biologists.

I think that suits the creationists. They can misrepresent evolution and the work of scientists all they want knowing that the majority of the faithful will be reading only their side of the story. That is the reason for the conditions they have recently put on debating the fused chromosomes with Carl Zimmer. It has to be on their moderated web site with a word limit with no comments allowed.

Tuesday, July 17, 2012

Indian Baked Beans And American Natural Gas

This bean is an annual legume. The New York Times has an interesting article on the sudden demand from U.S. shale gas drillers for the guar bean grown in the arid state of Rajasthan. The bean powder is used in making fracking more effective.

Guar, a modest bean so hard that it can crack teeth, has become an unlikely global player, and dirt-poor farmers like Mr. Singh have suddenly become a crucial link in the energy production of the United States.

For centuries, farmers here used guar to feed their families and their cattle. There are better sources of nutrition, but few that grow in the Rajasthani desert, a land rich in culture but poor in rain. Broader commercial interest in guar first developed when food companies found that it absorbs water like a souped-up cornstarch, and a powdered form of the bean is now widely used to thicken ice cream and keep pastries crisp.

But much more important to farmers here was the recent discovery that guar could stiffen water so much that a mixture is able to carry sand sideways into wells drilled by horizontal fracturing, also known as fracking. 

The worry is that guar production in Rajasthan depends entirely on a good monsoon. So far this year rains have been deficient. Based on previous years surging sales, farmers have suddenly come into money and are spending freely. Hope the monsoons are normal this year too and one also hopes that poor farmers who have money to spend take sensible advice on managing their new found incomes.

A second worry and one for Indian agriculture is - will excessive demand for Guar, not just from the U.S., but from other countries including eventually from India start eating into farmland currently growing food crops?..Unless off course an alternative to Guar is found.. a possibility that Rajasthan farmers should also acknowledge and prepare for.

Two Geologists In A Rift Valley

From xkcd comics:

Am not sure about a rift and an orogeny with thrust faults being situated in the same valley... but who can argue with the ending!

Tuesday, July 10, 2012

Gold And Metal Exploration In The Deep Sea

The recent interest in metal sulphide deposits localized around deep sea hydrothermal vents has been nicely summarized in an article in the New York Times.

Gold and copper are the main metals of interest along with silver, zinc and cobalt. The deposits are not randomly distributed on the sea floor but are near undersea volcanic activity with the Pacific areas along Papua New Guinea and Fiji being of special interest.

Years ago as a student I had visited the National Institute of Oceanography in Goa, India. At that time the thrust of research was on the origin and distribution of manganese nodules which could be found in several zones in the Indian ocean. That never became a commercial venture due to probably the low concentration of the nodules and the high costs of extraction.

These new ventures though are going to be operating on a gigantic scale:

...Last year, Nautilus won a 20-year lease to mine a rich deposit in the Bismarck Sea, in the southwestern Pacific. The mounds are a mile down. The company says the site holds about 10 tons of gold and 125,000 tons of copper.

Nautilus plans to start mining next year but also cites possible delays. It is building robots up to 25 feet tall that are to collect sulfides and pump them to the surface. Barges are then to carry the seabed minerals to Rabaul, a Papua New Guinea port some 30 miles away.

Robots 25 feet tall and maybe even taller in the future.

Hollywood won't be far behind..