Reporting on a Revolution

You'll Understand Homeopathy If You Understand Einstein

suvrat_k@yahoo.com (Suvrat Kher) — Fri, 06 Nov 2009 04:57:00 +0000

....Homeopathy - can it get more stupid than this...?

Warning: Advanced degree in physics and chemistry required to follow this discussion:

Now you know why those white pills pack so much punch! They are literally powder kegs of energy.

Isolating Nuclear Waste At Yucca Mountain

suvrat_k@yahoo.com (Suvrat Kher) — Thu, 05 Nov 2009 05:32:00 +0000

BLDGBLOG has an interview with Abraham Van Luik, a geoscientist with the U.S. Department of Energy.

Its a long interview about isolating nuclear waste. Yucca mountain and its geology feature prominently.

Definitely worth reading.

Teaching Human Evolution In Pakistan Can Be Dangerous

suvrat_k@yahoo.com (Suvrat Kher) — Thu, 05 Nov 2009 05:19:00 +0000

Kenneth Chang of New York Times has written an interesting summary on the teaching and acceptance of evolution across Muslim countries and among Muslim immigrants in many western nations.

Atomic physicist Pervez. A Hoodbhoy went through a dramatic moment while lecturing at a university in Pakistan:

Pervez A. Hoodbhoy, a prominent atomic physicist at Quaid-e-Azam University in Pakistan, said that when he gave lectures covering the sweep of cosmological history from the Big Bang to the evolution of life on Earth, the audience listened without objection to most of it. “Everything is O.K. until the apes stand up,” Dr. Hoodbhoy said.

Mentioning human evolution led to near riots, and he had to be escorted out. “That’s the one thing that will never be possible to bridge,” he said. “Your lineage is what determines your worth.”

Its scary that this took place not at some isolated madrassa but at a national university. Overall acceptance of evolution - especially human evolution - is low in Muslim countries. The technological advancement engulfing these countries is not necessarily paralleled by a more scientific mindset among citizenry. Religious beliefs are playing a large role in driving a wedge between the two. Turkey is a great example. Just 2-3 decades ago creationism was not a factor affecting science education in Turkey. Today, the influence of Islamic parties is greater in society, evolution teaching is diluted at the school level and creationist textbooks are influencing biology syllabus.

The article does not mention Muslims in India but I doubt if attitudes towards evolution are significantly different among Indian Muslims.

And I wonder what the break up would be according to educational level and how it compared to Hindus.

End Cretaceous: How Many Impacts? How Many Iridium Anomalies?

suvrat_k@yahoo.com (Suvrat Kher) — Mon, 02 Nov 2009 08:36:00 +0000

Looking over the recent GSA geoblogosphere page I was alerted to a presentation by Shankar Chatterjee and colleagues on the Shiva crater, a hypothetical impact crater that Chatterjee claims is of end Cretaceous age and is likely responsible along with the Deccan volcanism for the mass extinction. He suggests that the Chicxulub impact event in Mexico also timed to the end Cretaceous did not alone cause the mass extinction.

Here is the abstract. The talk apparently got a skeptical reception. Chatterjee envisions the following scenario. The meteor hit the Indian continental plate and maybe initiated rifting between Seychelles and India.

Source: Chatterjee- Proc 30th Int. Geol. Congr. Vol 26, pp - 31-54

The crater is now broken up along the rift. Part of the structure lies along the Indian west coast and part of it along the Seychelles margin.

The argument is at present based mostly on the geometry and structure of the basins and rifted margins matching what a meteorite hit will produce if it hit the crust at a shallow angle from the southwest.

But according to what I have read so far there is little direct local evidence of this being an impact crater. There is no core recovered from the supposed impact site and so no information available on whether the features that are seen at the Chicxulub crater in Mexico i.e. impact melt rock, high pressure quartz phases, chaotic breccia, tsunami deposits and so on are present at this site too. Also Chatterjee has not given as far as I know a convincing account of why various models of continental rifting, flood volcanism and denudational isostacy are inadequate explanations of the continental margin geology of west India and the Seychelles.

Yet, end Cretaceous always fascinates.

Chatterjee think this impact occurred either simultaneously with the Chicxulub impact or it post-dates the impact in Mexico. I found this view point very interesting for the response it drew from Gerta Keller who is a strong proponent of the theory that the Chicxulub impact was not the primary cause of the K-T extinction. She is pushing for the Deccan volcanics being the real culprit.

Keller has been quoted rejecting Chatterjee's theory, saying there is no evidence for such an impact in Indian deposits. But she leaves a big question unanswered, one that is prompted by her own work and theory.

How do you explain the iridium anomaly associated with many K-T boundary sediments?

Keller contends that the Chicxulub impact took place about 300,000 years before the K-T boundary (read the debate here). The iridium anomaly at the K-T boundary is widely acknowledged - including Keller - to be of meteorite impact origin. In a previous paper she has proposed the possibility of multiple impacts to account for this iridium anomaly, even naming the Shiva crater as a potential candidate for a second impact site.

Now she seems to be against the Shiva impact theory and cites a lack of local evidence in Indian continental deposits for the Shiva impact event, but see....let me add an intriguing possibility... the Deccan volcanics complicate the stratigraphy and everything depends on the exact timing of the impact. If the impact did not coincide with deposition of sediments and instead took place during eruptions, then all that evidence could be lost..obliterated within the lava flows. At end Cretaceous in the Indian continent these events, volcanism and sedimentation phases, alternated over periods of tens to a few hundred thousand years, and how can one be sure if the impact didn't coincide with a period of non-deposition and volcanism?

Given Keller's strong stance that there was no single smoking gun for the K-T mass extinction its a little bizarre that she is now dissing Chatterjee's hypothesis so readily and apparently rooting for the Deccan volcanics as the smoking gun!

So one impact definitely but how many more? ...still unanswered..

The most sympathetic view of Chatterjee's hypothesis was from The Economist who suggested that if the Shiva impact post-dates the Chicxulub impact, there should be two stratigraphically separated iridium enriched layers. The article pointed out to the Anjar deposits in west India as a site which might contain these two iridium anomalies.

I followed up on the work on the Anjar sediments. These are lacustrine (lake deposits) inter-trappean sediments i.e. they are sandwiched between Deccan volcanic layers. Magnetostratigraphy indicates the sediments to be deposited in the latest Maastrichtian (the uppermost division of the Cretaceous) within the magnetic zone 29R (R- reversed magnetic field), which contains the K-T boundary at many locales. There are three iridium enriched layers each occurring below a clay rich bed.

Sounds like an ideal candidate in support of multiple impacts.

...Except there seems to be no evidence that these iridium anomalies are due to meteorite impacts or that they encompass the K-T boundary. Geochemical analysis shows that the section lacks the negative carbon isotope excursion that is characteristic of the K-T event found in terrestrial deposits elsewhere (see here). There is evidence in the form of high temperature low pressure cristobalite ( a variety of quartz) in the clay beds associated with the iridium (see here) that these could represent leaching and enrichment from a alkali volcanic tuff. Impact deposits should contain high pressure varieties of quartz.

Early alkali Deccan volcanics along the western margin of the rifted Indian continent are known to be enriched in iridium (see here) and leaching and secondary enrichment could form concentrated iridium layers.

Finally the sediment above the iridium enriched layers contain dinosaur egg shells and late Cretaceous ostracods (see here). Along with sedimentological features this indicates that the iridium layers at Anjar predate the K-T extinction significantly and were formed in the early part of magnetic cron 29R.

It does not appear that these particular iridium layers are a result of the Shiva impact if it did occur. These deposits are well within the impact fallout zone for the Shiva impact and should have contained direct impact evidence like shocked quartz.

So....looks like many iridium layers but not all of them associated with the K-T boundary or with meteor impacts.

The Chicxulub impact and the Deccan volcanism overlapped. The stratigraphy of end Cretaceous is going to be messy and it won't be possible to sort out events that took place with a few tens of thousands of years of each other and tie them to either an impact or volcanism. If there was a second impact its record could easily be amalgamated with that of volcanism and very hard to resolve within Indian continental deposits as an independent event .

Direct drilling and study of the recovered core from the Bombay High basin basement which is supposed to be the impact site should decide the issue

...if and when that data comes around.

My head is reeling with these details and nuances. I'll leave readers to sort through the evidence.

Cambrian Explosion: This Time Its The Calcium That Did It

suvrat_k@yahoo.com (Suvrat Kher) — Wed, 28 Oct 2009 07:49:00 +0000

Geological processes and evolution - 4

A short article in Science Daily describes research that suggests that a buildup of calcium in the oceans in the early Cambrian provided the necessary trigger for the Cambrian "explosion" - the pronounced expansion and diversification of multicellular groups of animals. Some of the best examples of this evolutionary radiation is preserved in deposits like the Burgess Shale and the Chengjiang strata.

Here is the one sentence summary-

The researchers succeeded to show that the massive and sudden surge in the calcium concentration of the Cambrian seawater -- that is believed to be the result of volcanically active mid-ocean ridges -- not only initiated the buildup of calcified shells, but was also mandatory for the aggregation and stabilization of multicellular sponge structures. This allows, on the other hand, to formulate a novel theory where the geologically induced increase of marine calcium might be the key for understanding the Cambrian Explosion of Life.

There is deja vu when I read another ultimate causative explanation for the Cambrian explosion. Over the years you could write a similar sentence but substitute the word calcium with the sudden increase in oxygen, the warming of the earth following the thawing of the snowball earth, the increase in shallow shelf areas following marine transgression, all proposed as a one point explanations of this evolutionary phase in earth history.

Reading the press release you get a sense that the Cambrian explosion coincided with the origin of multicelluarity. Take this sentence:

However, the causes of its origin have been the subject of debate for decades, and the question of what was the trigger for the single cell microorganisms to assemble and organize into multicellular organisms has remained unanswered until now.

Its important to make a distinction here between the origin of a system and its subsequent diversification. Groups like fungi, plants and animals have evolved multicellularity independently of each other. Whatever triggered single celled animals to assemble into multicellular ones (metazoans), that transition did not happen in the Cambrian but much before in the late Proterozoic maybe as much as 50 -100 million years before.

The original study recognizes this point but it gets lost in the press release.

There is a good and improving fossil record of metazoans from the late Proterozoic Ediacaran fauna and other types of fossil preservation that indicates that molecular mechanisms for cell to cell signaling and cell adhesion must have evolved well before the Cambrian. Multicellularity in animals originated long before the Cambrian explosion occurred and long before the rise of calcium in Cambrian sea-water.

The figure below summarizes the current fossil record of the evolution of metazoans. The Cambrian "explosion" corresponds with the Chengjiang fauna.

Source: On The Origin of Phyla

Explanations of the origin of metazoans and subsequent evolutionary radiations like the Cambrian explosion involve long and intertwined causal chains. A rise in oxygen by late Proterozoic may have favored larger body size and one solution to achieve this large size was to aggregate into colonies of cells which eventually became integrated as one organism. The marine transgressions by late-Proterozoic early Cambrian expanded available shallow marine shelf areas and created large and diverse ecologic niches for evolutionary diversification to take place. The evolution of predation would have set forth selective pressures for skeletonization. Many organisms would have taken opportunistic advantage of the rise of calcium in sea-water to boost skeletal production. Likewise calcium may have provided stability for even larger masses of cells to aggregate.

There were many geological and ecological factors at play feeding of each other that were responsible for one of the major transitions in the history of life. Insisting on just one cause as the most important to the exclusion of others is too simplistic.

The Latest Numbers On Arctic Oil and Gas Potential

suvrat_k@yahoo.com (Suvrat Kher) — Sat, 24 Oct 2009 17:02:00 +0000

Some interesting readings I came across on hydrocarbon resources and challenges over the last few days.

Geology.com has published a report by the Energy Information Administration on the latest estimates of undiscovered technically recoverable oil and gas resources of the Arctic basins.

And the number is large - about 400 billion barrels of oil equivalent or about 20 odd percent of the world's undiscovered resources. This is an estimate based on occurrence of geologically favorable conditions in various Arctic basins. These are resources or potential. They will be or rather a fraction of these will be added to reserves only when someone drills and more directly estimates the amount of hydrocarbons that can be economically recovered.

We won't be running out of oil and gas or other fossil fuels like coal soon, geologically, and BP's chief executive officer Tony Hayward thinks that in 2030 fossil fuels will still be meeting 80% of the world's energy needs. He explains his position in a speech given at the Oil and Money conference, London. The title of the conference conjures up images of greedy petro-oligarchs doing everything to maintain a vice-like grip on the supremacy of fossil fuels, but the changeover to renewables won't be easy given the enormous gap that exists between the contributions from fossil fuels and renewables to our energy mix. India for example generates 70% of its electricity from coal and has plans to build plenty of coal fired power plants in the near future. The contribution of solar and wind to power generation in India is currently negligible. The U.S generates about 46% of power from coal and the contribution of non-hydro renewables to power generation is just 3%.

If fossil fuels are going to be an important if slowly declining part of our energy mix for some time to come then Geoffrey Styles of Energy Outlook argues that we rethink our reluctance to pursue low emissions strategies like carbon capture and sequestration (CCS). He writes on not just the technological and economic challenges facing CCS but also a public backlash against it based on - he thinks - a lack of education among the public about geological principles and the efficacy and safety of CCS.

Plenty to think about as the Copenhagen climate change summit nears.

How Much Oil Underneath?

suvrat_k@yahoo.com (Suvrat Kher) — Wed, 21 Oct 2009 07:00:00 +0000

A friend asked me a few days ago why the Karnataka government were giving two different estimates for iron ore potential in the state. One file says that the iron ore reserves are about 3,447 million tonnes, while another department file says that the state has about 9,000 million tonnes of iron ore resources.

I replied that assuming the Karnataka government is using the words as they are commonly used in industry, reserves are the fraction of resources that can be economically exploited at any given time. Neither is a static quantity. Both will change given new finds, technological breakthroughs that enable recovery of previously out of bound deposits and the economic and political climate.

Coincidentally Scientific American has an article in their recent issue on the current reserves of oil and how that quantity is changing with new finds and new technology. They give one example:

When Kern River Oil Field was discovered in 1899, analysts thought that only 10 percent of its unusually viscous crude could be recovered. In 1942, after more than four decades of modest production, the field was estimated to still hold 54 million barrels of recoverable oil, a fraction of the 278 million barrels already recovered. “In the next 44 years, it produced not 54 [million barrels] but 736 million barrels, and it had another 970 million barrels remaining,” energy guru Morris Adelman noted in 1995. But even this estimate proved wrong. In November 2007 U.S. oil giant Chevron, by then the field’s operator, announced that cumulative production had reached two billion barrels. Today Kern River still puts out nearly 80,000 barrels per day, and the state of California estimates its remaining reserves to be about 627 million barrels.

This story will apply to a wide range of mineral/oil deposits all over the world. Famously the United States has produced a cumulative 200 billion barrels of oil from reserves that never at any one time exceeded 40 billion barrels.

In the many responses to the Scientific American article I thought this one from JR Wakefield stood out as it explains what peak oil means from different perspectives:

Its not about how much oil is in the ground, it's how fast you can get it out and at what net energy. This thus article is highly misleading. Here are the Five Horsemen of Peak Oil:

1) Geological Peak. That is the point where we have consumed half the oil in the ground. So far we have consumed a trillion barrels. Estimates of remaining oil range, but the number appears to be 3 trillion barrels remaining in the ground. So we are not at geological peak. Hence skeptics of peak oil use this for their arguments, like this SA article does.

2) Flow Rate Peak. That's the point at which you cannot extract the oil fast enough to meet demand. This is especially so with old fields in decline (which is a fact) and new fields which have difficult geology (like this one). The flow rate from them does not keep up with decline, nor keep up with growing demand. The article failed to mention that North Sea is all in terminal decline and the UK has to now import oil. Indonesia peaked years ago and has to import oil forcing them out of OPEC. The Cantarell field in Mexico, the third largest in the world, and the US's 3rd import source, was producing 2.3mb/day at it's height. Today it's 560kb/day with a 41% drop from last year. WE ARE AT FLOW RATE PEAK NOW.

3) Geopolitical Peak. That's when exporting countries, due to their own growing demand, decide not to sell their oil abroad any longer but decide to keep what's in the ground for their own future domestic needs. So far only the US does this, but expect other countries to soon follow that.

4) ERoEI peak. This is the point at which it takes as many joules to extract the oil than you get from the oil extracted. That is, one barrel in to get 1 barrel out. Conventional wells in the 1960s were 100:1. That has dropped to about 25:1 today. Aging fields and new unconventional fields have very low ERoEI. The tar sands in Alberta for example is less than 6:1. Our entire society is based on the NET energy, not what's extractable. Calculations show that we will reach over all break even in oil extraction between 2020 and 2030. Once that is reached it basically means we have completely run out of oil.

5) economic peak. This is the point where the economy cannot tollerate high oil prices and plunges the world into a recession, like this one which was caused by $140.barrel oil.

The challenge before us in terms of combating global warming is to ensure a transition from hydrocarbon energy to low emissions renewable energy much much before we start running out of the stuff not just in geological terms - which is not going to occur anytime soon - but by the other measures like Flow Rate and ERoEI as well. Likely even the Flow Rate Peak and the ERoEI peak are not constant but will keep shifting as more efficient ways of extracting oil and other hydrocarbon resources are discovered.

The Probability Of Evolutionary Pathways

suvrat_k@yahoo.com (Suvrat Kher) — Mon, 19 Oct 2009 06:07:00 +0000

Joe Thornton of the University of Oregon and the Howard Hughes Medical Institute writes these thoughts about how to understand and appreciate the probability of evolution following one specific pathway among many possible:

Consider the future: there are countless possible that could emerge from our present state, making the probability of the one that actually does evolve extraordinarily low. Does this mean that the future state that will ultimately emerge is impossible? Obviously not. To say that our present biology did not evolve deterministically means simply that other states could have evolved instead; it does not imply that it did not evolve.

Consider your own life history as an analogy. We can all look back at the road we have traveled and identify chance events that had profound effects on how our lives turned out. “If the movie I wanted to see that night when I was 25 hadn’t been sold out, I never would have gone to that party at my friend’s house, where I met my future spouse….” Everyone can tell a story like this. The probability of the life we actually lead is extraordinarily small. That obviously doesn’t mean that its historical unfolding was impossible.

That we inhabit an improbably reality requires a divine explanation only if we, like Behe, take the teleological view that this is the only reality that could exist. But if we recognize that the present is one of many possibilities, then there is no difficulty reconciling the nature of evolutionary processes with the complexity of biological forms. As history unfolds, potential pathways to different futures are constantly opening and closing. Darwinian processes are entirely adequate to move living forms along these pathways to a remarkable realization – but just one realization out of many others that could have, but didn’t, take place.

Beautifully written.

The entire article is worth reading as it explains how complex traits with interlocking components can evolve through a combination of natural selection and random genetic drift acting on adaptive mutations and neutral intermediates. And this is not just theory. Joe Thornton leads a team that does experiments to show how this can happen. The article encapsulates modern evolutionary thinking about the evolution of complexity quite well.

That it is a devastating put down of the arguments made by the Intelligent Design community makes it especially pleasurable to read.

A 20 Million Year History Of Atmospheric CO2

suvrat_k@yahoo.com (Suvrat Kher) — Fri, 16 Oct 2009 05:20:00 +0000

From Brave Blue Words I found out a day late that yesterday was Blog Action Day for Climate Change. Bloggers all over the world are writing about various aspects of climate change.

Being a geologist I want to point to a study that reconstructs atmospheric CO2 levels as far back as the Miocene - a 20 million year history. Atmospheric CO2 levels have been reconstructed with some confidence for the last 800,000 years or so using gas bubbles trapped in the Antarctic ice sheets. Before that the data was thin.

Aradhna Tripati and colleagues have used the boron to calcium ratio in foraminifera shells to calculate ancient CO2 levels. As atmospheric CO2 increases some of it diffuses into the ocean increasing the dissolved CO2 content of sea-water. That in turn reduces the amount of boron that is incorporated in a growing calcium carbonate shell of the foraminifer individual. The variation in the boron to calcium ratio over time as recorded in foraminfera fossils of different ages should tell us something about transitions in CO2 levels.

The scientists first validated their calculations using the 800 K record of CO2 trapped in ice. They compared their results with those obtained by the direct measurement of CO2 trapped in gas bubbles. It was a good match. The scientists calculate that the uncertainty in their results is about 14 parts per million.

Their results show that there is a close coupling between CO2 levels, sea-level and temperature over the last 20 million years. In the middle Miocene (~ 20 ma) CO2 levels were about 400 ppm - comparable to modern levels - and that sea-levels at that time were 30 -40 meters higher than today (geologists estimate this using distribution of ancient shorelines), with temperatures about 3-6 deg C higher (using geochemical proxies like the oxygen isotope composition of shells which depend partly on temperature of the water from which they precipitate). Decreases in CO2 levels in the later part of Miocene and Pliocene were synchronous with major episodes of cooling and glacial expansion.

Its important to establish that historical connection to answer doubts expressed on what exact impact would increasing levels of CO2 have on climate and sea-level. Many climate change doubters are not happy with computer simulations and models of CO2 increase and climate change. This study shows that CO2 has been a strong driver and amplifier of climate change in the deep geological past. History is also a guide and often a reliable one.

Go here for the press release.A minor quibble. The press release calls the shells used by the scientists as belonging to single celled marine algae. Foraminifera are not algae. They are protists.

A Government Scientist Speaks Out On Flood Management

suvrat_k@yahoo.com (Suvrat Kher) — Wed, 14 Oct 2009 15:54:00 +0000

You don't hear many Indian Government scientists opining about science, policy, the environment, civic criticism...well you get the picture.

There are restraints....to put it politely.

But Chetan Pandit of the Central Water Commission has broken the shackles and in the October issue of Current Science comes out sparring strongly against - in his opinion - the woolly headed arguments of the environmental community and the media on the subject of big dams and flood control.

He puts forth several fallacies and myths regarding dams and flood control and argues very well that big dams have served as effective flood managers.

And I had to chuckle at this:

We Indians seem to be particularly susceptible to this ‘romancing with the past’. Everything, be it water management, or agriculture, Ayurveda, mathematics, literature, astrology, etc., we like to believe that in India all learning had reached its peak in some distant past, and the best thing for us to do is, to continue to do what our ancestor’s did. And this is given a lofty name ‘wisdom of the centuries’.

You may be inclined to view big dams as destroyers of forests and biodiversity and so on but Chetan Pandit has made some good points about the intellectual environment in which debates on these issues take place and are presented to the public in India. One of the most important points he makes is that many people who get involved in criticizing government projects are numerically challenged. Arguments are high on the emotional quotient but there is little quantitative analysis of data to go with it.

I am sure not all environmentalists are so mathematically naive, nor should every developmental project be reduced to just numbers. But this is a government scientists view. When presented with a rare opportunity to speak out he doesn't restraint himself.

Read the article here.

Update: Chetan Pandit via an email to me wants to clarify:

I never said that those criticizing government projects are “numerically challenged”, or mathematically naïve, etc. Even a high school student would be able to import the data on flood affected area into a spread sheet and plot a graph to see whether or not there is any increasing trend. What happens is, if they do that their argument will collapse, the numbers do not favour them, they know it, and therefore they have to willfully ignore the numbers. Which is why I wouldn’t describe the environment in which debate takes place as “intellectual”. It is pseudo-intellectual.

Chetan Pandit

Sure, he didn't use the words numerically challenged and mathematically naive. Those are my words but he does imply this. For example he writes about noted anti-dam activist Shripad Dharmadhikary -

In his exhaustive critique of the Bhakra dam, noted anti-dam activist Shripad Dharmadhikary writes, ‘Even after the Sutluj flows were augmented by the transfer of Beas water into the Bhakra reservoir, the reservoir has not filled up in most of the years’4. This was probably intended as a critical comment on filling of the Bhakra reservoir. But its implication, which probably escaped Dharmadhikary, is – Bhakra is very successful in flood control. In the years, the dam did not even fill; it is obvious that all the floods were absorbed 100%. And this, despite transfer of a substantial quantity of water from Beas to Sutlej through the Beas–Sutlej link.

But its implication, which probably escaped Dharmadhikary,...

So I read this as meaning Dharmadhikary did not understand the topic well enough. It certainly doesn't read as meaning that Dharmadhikary churned out the numbers, didn't like what he saw and then ignored the finding.

Dinosaur Eggs And Some Stratigraphic Thoughts

suvrat_k@yahoo.com (Suvrat Kher) — Mon, 12 Oct 2009 07:18:00 +0000

The discovery of dinosaur eggs from Cretaceous fluvial sediments near the village of Ariyalur in the state of Tamil Nadu , South India is getting lots of press cover ...here and here. Hundreds have been found in clusters of about 8 over an area of about 2 sq km. Looks likely to be a nesting site. On a sadder note I read in the Times of India a few days ago that there has been no protection given to the site by the government despite requests from the scientists. Locals are already taking away the fossils eggs and disturbing and damaging the site in the process. What a shame!

There also has been some silly press coverage calling this a Jurassic treasure trove, a holdover of the popular link between anything dinosaur and the word Jurassic....as in Jurassic Park the movie. This particular south Indian sedimentary basin does not have Jurassic sediments. It contains an Early Cretaceous to Early Cenozoic sequence.

What caught my eye was that the sedimentary layer containing the eggs were capped by a volcanic layer. The scientists from Periyar University, Salem, seem to think that this volcanism represents the Deccan volcanic activity dated to around 65 million years ago and that the field relationship between the volcanic layer and the underlying sediment could suggest that this particular volcanic event may have killed or damaged those eggs.

I don't know enough details about the deposit to answer that with certainty but I did have some random thoughts on event deposits i.e layers deposited almost instantaneously and how geologists use such deposits to ascertain the age of the associated sediments. In this case they suggest that sedimentation and the volcanism took place in quick succession and by quick I mean volcanism took place immediately after the dinosaurs laid those eggs....before those eggs hatched.

If a sediment unit is capped by a volcanic layer that is dated to say 65 ma (million years old) then that would mean that the sediment cannot be younger than 65 ma. But does the relationship mean that the sediment too is 65 ma? And what does it mean when you say the sediment is 65 ma. How much 65 ma plus minus ...years, or uncertainty is there in a calculation like this?

Lets say we get lucky and that the sediment layer is sandwiched between two volcanic layers that can be dated with radiometric methods. Let's say both layers give a date of 65 ma. What does that tell you? Radiometric dates that old come with a sizable uncertainty on the order of hundred thousand years or so. That means the date of the overlying layer might come out as say 65 ma with an uncertainty of 300 thousand years. The date of the layer underlying the sediment may come out say 65.2 ma with an uncertainty of 300 thousand years. The two dates are statistically unresolvable. So even if the sediment is sandwiched between two volcanic layers that indicate the same statistical date there could still be a time lag of tens to a hundred thousand years or so between the sediment being deposited and the volcanic activity.

Fossils are not much use either for this purpose. Fossils can eliminate the possibility that the events took place in quick succession if the sediment contains fossils which are obviously much older that 65 ma. But again fossil species have temporal ranges of a hundred thousand years or more. Even if the sediment underlying the volcanic layer contains fossils that are indicative in this case of the latest Maastrichtian age (close to 65 ma) there will be an uncertainly of tens of thousands of years and so their presence won't resolve events taking place on smaller time scales.

Geologists have then to rely on the detailed physical relationship within and between the sediment and the volcanic material.

Preserved sedimentary layers are mostly time averaged deposits. That means that material at the bottom of a particular bed is not necessarily older than the material in the upper part of the same layer. During deposition waves and currents keep reworking the same bundle of sediment. Animals may burrow into it and churn up sediment. Material at the bottom part may get transported to the upper part of the layer. The layers thus becomes time-averaged. Organisms who have lived at different times through that depositional episode are all distributed randomly - with respect to their age - throughout the deposit.

A good recent example of a time averaged deposit is the sediment unit that contains the remains of Ardipithecus ramidus the early hominin found in Ethiopia. Scientists lucked out there and realized that the sediment is sandwiched between two volcanic layers dated to about 4.4 ma. Each layer differed in their radiometric age by about 30 thousand years with an uncertainty of about 75 thousand years. Based on this information and the internal characters of the layers the scientists concluded that the geological unit was a time averaged deposit representing a few thousand years of deposition.

This layer containing the dinosaur eggs does not have the characters of a time averaged deposit at least not one representing hundreds or thousands of years. The eggs were found in clusters of 7-8 eggs per nest and these nests are found in successive layers of the sequence. These two indicators suggest that the sediment was not disturbed much. Rather the setting, fluvial floodplains would have meant that the eggs were buried rapidly and entombed during seasonal floods, sorts of event deposits just like volcanic eruptions. That may have been the main cause of the eggs not hatching. The layers immediately underlying the volcanic cap may thus represent sedimentation taking place over a few tens of years, each nest bearing layer essentially preserving or freezing ecosystem conditions as they existed at that time. There is the possibility that the uppermost layer containing eggs represents maybe the last egg laying season before the eruption.

Volcanism when it occurred would have sealed the deposit from further damage from the elements. How close in time was that event to the last egg laying season? Again the scientists will have to look closely at the relationships. Are the eggs in the uppermost layers caked with volcanic ash? Do they show signs of being baked or cracked due to heat, a kind of a Cretaceous hard boiled feast?

Detailed sedimentology and stratigraphy will provide more clarity than absolute radiometric dating and fossil ranges when posed with questions of this nature.

Its Hard To Classify That Archaeopteryx

suvrat_k@yahoo.com (Suvrat Kher) — Sat, 10 Oct 2009 04:11:00 +0000

How birdlike was Archaeopteryx?

Beak - Yes
Feathers - Yes
Wishbone - Yes

Growth pattern of blood vessels - Not quite there yet

By comparing the structure of the bone of Archaeopteryx with modern birds and fossil dinosaurs, researchers found out the growth pattern of blood vessels in Archaeopteryx was more like dinosaurs than modern birds. Archaeopteryx individuals seem to have taken a longer time to mature than modern birds do.

Archaeopteryx lived about 150 million years ago and is the earliest bird-like creature to have been found yet. A younger bird-like fossil -Ichthyornis dispar - dated about 94 million years ago shows several characteristics of quick growth, giving us an idea of the timing of the various changes in morphology and physiology that were taking place within the Maniraptor dinosaurian clade as they evolved characteristics that are recognized as bird-like.

By the way this is not some earth shattering find. The basic relationship that small carnivorous dinosaurs evolved into birds still holds. But the study highlights how difficult categorizing a creature which is a composite of ancestral and derived traits can be.

It doesn't matter in the larger view if Archaeopteryx is classified as a dinosaur or a bird. The value is in demonstrating that evolution of a complex suite of characters takes place in fits and starts, some features evolve earlier than others preserving the historical trajectories that major transitions in evolution have taken.

Go here for the lighter version.

Physicist Extraordinaire- Science Friday On A New Book On Paul Dirac

suvrat_k@yahoo.com (Suvrat Kher) — Tue, 06 Oct 2009 05:04:00 +0000

Science Friday has a really interesting talk with Graham Farmelo on his new book on Paul Dirac - The Strangest Man: The Hidden Life of Paul Dirac, Mystic of the Atom.

What's my connection to this great man? Later in his career Paul Dirac joined Florida State University, Tallahassee which was my Alma mater too. I walked often past his statue on the way to the Dirac Science Library.

Farmelo gives a good account of Dirac in that talk as a reticent personality, who avoided people...but not unaware of the importance of knowing the right people....he did make sure he was standing right behind Einstein in a group photo at a conference.

Meanwhile from my book shelf in one of the best science autobiographies I have read- Sir Fred Hoyle's vibrant and entertaining Home Is Where The Wind Blows- I found the following nuggets about Hoyle's interaction with Dirac:

Shortly after inveigling me into the secretaryship of the Delta-Squared V Club, Maurice Pryce left Cambridge to take up a lectureship at Liverpool University. If I was to retain my student status with the Inland Revenue, another research supervisor was therefore needed. Pryce suggested Dirac, so I went to Dirac and explained the situation. Although normally he didn't accept students, Dirac broke his rule on this occasion because he simply couldn't resist the circular counterlogic of a supervisor who didn't want a research student who didn't want a supervisor.

and...

More than any other person I have known, Dirac raised the meaning of words and syntax to a level of precision that was mathematical in its accuracy. He had nothing at all of the irritating habit of attempting to read hidden significance into your remarks. He paid everybody the compliment of supposing they knew exactly what they were saying, a compliment he sometimes took to extreme lengths.

how great was Dirac..?.......like truly great minds he is posthumously productive... says Farmelo.

Indian Groundwater Extraction May Be Contributing To Sea Level Rise

suvrat_k@yahoo.com (Suvrat Kher) — Sun, 04 Oct 2009 05:09:00 +0000

I don't know what to make of this calculation which I picked up in a New Scientist story. A few weeks ago there was a study using NASA's Grace satellite measurements that showed an increase in groundwater extraction from North Indian aquifers.

A second study on these satellite measurements asserts that the groundwater loss amounts to about 54 cubic km per year over a time period of 2002 and 2008. A lot of this extracted groundwater ends up in the sea and could be contributing to raising sea-levels by 0.16 millimeters every year, about 5% of the total sea level rise. That is about the same as contributed by runoff from melting Alaskan glaciers the authors conclude.

I don't have access to the full paper so I don't know the details of the calculation but here is what the scientists have to take into account:

Part of the groundwater extracted will be taken up by plants and remain there over the life of the plant and make its way into the food chain.
Part of it will be lost through the plants through evapo-transpiration.
Part of the water will remain in soil adhering to clay and sand particles.
Part of it will make its way back to the aquifer.
Part of it will make its way through the soil to local streams and eventually to the sea.
Part of it will be lost by direct evaporation. That evaporated water (and the water lost by evapo-transpiration) will fall as rain and part of it will infiltrate as groundwater and part of it will be surficial runoff into streams and eventually into the sea.

Just giving you something to think about what happens to extracted groundwater.

Not Left Out! My Interview At The Reef Tank Is Online

suvrat_k@yahoo.com (Suvrat Kher) — Tue, 29 Sep 2009 16:01:00 +0000

There is a geology bonanza going on over at The Reef Tank which is a blog and forum dedicated to marine science topics including climate change, marine energy, ocean acidification and marine conservation. There have started a marine geology section in their community blog. Brian@ Clastic Detritus was the first to be interviewed. Dr. Erik W. Klemetti of Eruptions was second. The Lost Geologist was interviewed a few days ago.

Now its my turn. My interview is online (thanks to Brian who recommended my name) on their community blog page. I thought the questions were quite challenging and interesting dealing with how carbonate sedimentology relates to marine sciences and ecosystems and what my background in carbonates tells me about the current crises marine ecosystems may be facing due to global warming. There were a couple of questions on my posts on groundwater.

My favorite question though and I thank Ava the blog moderator for asking that-

You also blog on evolution. How important was/is marine life and marine ecosystems to the theory of evolution and why?

I got a chance to write about how carbonate sediments help us understand evolution and also the question gave me a chance to highlight the work of two of my advisers who inspired me into studying carbonates and evolution.

Go over to The Reef Tank and take a look.

Genetic Ancestry of Indians. A New Paper Is Creating a Ruckus

suvrat_k@yahoo.com (Suvrat Kher) — Fri, 25 Sep 2009 07:29:00 +0000

A new paper about the genetic history of Indian populations in Nature is making waves in press releases. A reader asked me if I could explain the finding in plain english. Since I am not an expert in population genetics I will instead point to two posts that have dissected the paper. John Hawks writes about the topic here. Gene Expression details it here.

The salient points as I understand:

1) This is not some pioneering work as some of the Indian press reports suggest it is. The broad finding of this study have antecedents and are not that surprising or shocking.This study though does expand on earlier work by using a larger number of genetic data points and so is significant in its scope.

2) Modern Indian populations are derived from two ancient populations referred to as the Ancestral North Indians (ANI) and the Ancestral South Indians (ASI). Ancestral North Indians were Caucasoids, genetically closer to Eurasians, Europeans and central Asians while the Ancestral South Indians were distinct from Caucasoids and Mongoloids. The Onge of the Andamans are a good model for the original Ancestral South Indians. The modern Indians are admixtures of these two populations (the Onge are not ancestral but an early branch of the ASI)

3) The findings indicate that there is a larger amount of genetic variation between Indian groups than there is between say European groups. This the authors suggest is a result of a small number of individuals founding different ethnic groups that then remained endogamous and therefore genetically divergent. This has important medical value as recessive diseases may correlate with ethnic groups.

4) Despite these inter group differences on average Indians from various groups and across castes are more closely related to each other than they are to outgroups like Europeans or East Asians. This points to the deep residence time of people in the subcontinent and continued gene flow across groups. This has led to reporting in the press that there is no north south divide and the Aryan-Dravidian divide is a myth. Again this finding is not new. There is earlier work that suggest similar genetic relationships among Indians.

5) The study also clearly shows that for some genetic lineages there is a gradient in relationship to ANI (west Eurasian) that is a function of geography and caste. For some genes north Indians (Indo European speakers) and upper castes are more closely related to ANI than are south Indians and lower castes. Here is a table that summarizes this result. The first few samples in the table are from south India (Dravidian and Tribal) and the lower portion of the table represents north Indians (Indo-European speaking people).

6) The paper says little about when this admixture with west Eurasian genes occurred but hints it may coincide with the arrival of Indo-European speakers which has generally been timed post collapse of the Harrappan city states around 1800 - 1600 B.C. This is off course is a controversial topic. The amounts of admixture with ANI is high in some samples. This may be taken by some as a validation of the Aryan Invasion scenario in which there was a massive migration and population replacement of indigenous people in northern India by Indo-European tribes. I don't see it that way. The northwestern region has always been a conduit into India. There would have been people movements from the Central and West Asia into this region related to the spread of agriculture (6000 - 8000 B.C ?). City states like the Harrapan complex had extensive trading ties (2600 - 2000 B.C) with the Bactria Margiana Complex in the Turkmenistan - northern Afghanistan - Tajikistan - Uzbekistan area and with the Elamite civilizations in western Iran. The people involved in trading with these city states included those from the Pontic -Caspian Eurasian steppes.

So it is unlikely that any one historical event shaped these genetic relationships. Migration and population movements of Caucasoid people into India have been taking place longer than the advent of the Aryans although it does seem that the arrival of Indo-European speakers did leave a recognizable genetic imprint on older Indian populations.

7) The Indian Press has made a hash of the finding. For example they have only reported those parts of the study that deal with the kinship among Indians and have stressed that castes and tribes cannot be differentiated or that there is no divide between the Aryans (roughly north Indians) and Dravidians (south Indians). That is all true for average relatedness. But the study also clearly points out that there are genetic differences between north and south Indians and between upper and lower caste in terms of the degree of relatedness to Eurasians. North Indians and upper castes are more closely related to Eurasians. North Indian upper castes have even more Eurasian ancestry. This part was ignored by the press.

But I can't blame the press entirely. The scientists who gave interviews to the press didn't mention this. They wimped out on reporting this potential inflammatory and politically incorrect finding. This is just poor and irresponsible science outreach on part of the scientists. How can you ignore a finding that is staring out at you from the very paper you are talking about? The press may be guilty of not digging in but it was just reporting what the scientists told them.

Phew! We Finally Know When the Quaternary Period Began

suvrat_k@yahoo.com (Suvrat Kher) — Thu, 24 Sep 2009 16:14:00 +0000

Its official. The Quaternary now begins 2.58 Million years ago. Everyone knew the Quaternary corresponded with the ice ages but there was doubt on which geological horizon to use as a base.

In June 2009, the Executive Committee of the International Union of Geological Sciences (IUGS) formally ratified a proposal by the International Commission on Stratigraphy to lower the base of the Quaternary System/Period to the Global Stratotype Section and Point (GSSP) of the Gelasian Stage/Age at Monte San Nicola, Sicily, Italy. The Gelasian until then had been the uppermost stage of the Pliocene Series/Epoch. The base of the Gelasian corresponds to Marine Isotope Stage 103, and has an astronomically tuned age of 2.58 Ma. A proposal that the base of the Pleistocene Series/Epoch be lowered to coincide with that of the Quaternary (the Gelasian GSSP) was also accepted by the IUGS Executive Committee. The GSSP at Vrica, Calabria, Italy, which had hitherto defined the basal boundary of both the Quaternary and the Pleistocene, remains available as the base of the Calabrian Stage/Age (now the second stage of the revised Pleistocene). In ratifying these proposals, the IUGS has acknowledged the distinctive qualities of the Quaternary by reaffirming it as a full system/period, correctly complied with the hierarchical requirements of the geological timescale by lowering the base of the Pleistocene to that of the Quaternary, and fully respected the historical and widespread current usage of both the terms 'Quaternary' and 'Pleistocene'.

Confused? Me too!

What that means is that earth history can be subdivided into geological time units like the Quaternary based on some natural break in earth conditions. That break should be one of geological significance and one which is easily recognizable all over the world. In this case that break is the beginnings of the global ice ages at around 2.58 Million years ago and it is best represented by the geological section in San Nicola Italy which is being used as the standard or type section. A type section contains a continuous sequence of rock / sediment spanning the break. The base of the new geological time unit can thus be clearly highlighted in the rock record at the type section. Sections marking the beginnings of the ice age are found elsewhere too but it may be exceptionally well preserved at the type section.

Science Daily has the press release.

How Do We Know Fossils Were Once Living Organisms?

suvrat_k@yahoo.com (Suvrat Kher) — Tue, 22 Sep 2009 08:30:00 +0000

In the September issue of Geology there is a good give and take (open access) on the origin of early Neoproterozoic carbonate rock textures. The debate revolves around an interpretation made by Neuweiler et al. (2009) that certain cement filled cavity and mud textures in Neoproterozoic carbonate bioherms (carbonate mounds formed by aggregating and colonial organisms) look very similar to younger sponge replacement fabrics found in Palaeozoic and modern bioherms.

Even though there is no recognizable fossil sponge body parts in the studied Neoproterozoic carbonate (little Dal reefs, Canada) the authors interpret the diagenetic fabric as indicative of a metazoan origin (they say they cannot conclusively link it to any specific sponge taxon) pushing in their view the geological evidence for multicellular animals to around 875 million years ago. This is about 200 million years older than what most scientists acknowledge. Noah Planavsky in the comment section disagrees about the metazoan origins of the texture and suggests that microbiota can also form similar fabrics.

I found the study interesting in itself. I have worked with some pretty complex diagenetic fabrics and it is always a challenge to tease out components that are purely inorganic from those that have a biogenic origin.

I feel though that a study like this fulfills another important role in science - it is of epistemological value. I used to help my PhD adviser with the paleontology exhibit on Science Day at the local mall in Tallahassee and we had people coming up to us and asking " ...but how do you know that this fossil was once a living creature...?"

A study like this tells us about the methodology and chains of reasoning scientists use to gather a body of knowledge about how fossils form. In this case the authors compared sponge remains from modern bioherms with older and older deposits. In the modern bioherms the sponge organism had died relatively recently and the organic tissue and other skeletal parts were still joined together as a coherent organism. Some organic material had degraded and in its place were tiny carbonate crystals. In some internal body cavities carbonate mud had accumulated forming a sort of a cast of the body part. This is a clear indication that as organic material degrades its place is taken up by inorganic material which retains the same shape as the organic matrix.

The researchers then went further back in time and looked at Cretaceous and Paleozoic rocks. In these samples there was no organic matter, that had decayed away long back, but other typical sponge skeletal hard parts like spicules were still preserved and recognizable as sponge remains. The shape and form of the interior of the sponge the characteristic canal system was now completely filled by cement and mud. So although there was no coherent organism with linked body parts the association of spicules with a cement and mud filled connected cavity system which had a shape just like the canal system of the sponge gives us confidence that we are looking at sponge fossil fabrics.

One can then go one step further as the authors have done and interpret fabrics with characteristic shapes but no sponge remains (no spicules or anything) as having formed by the alteration of a large multicellular creature. That specific interpretation may be right or wrong in this case but that's the way scientists "know" that fossils were once living creatures. It's a good example to use to explain - How do we know what we know?

5 Things You Should Know About Evolution

suvrat_k@yahoo.com (Suvrat Kher) — Tue, 22 Sep 2009 03:31:00 +0000

Over at one of my favorite science /tech sites - Arstechnica - John Timmer has a good write up about 5 essential aspects of evolution that you should know:

A really inefficient solution can be a lot better than the alternative
Evolution solves problems in parallel
Evolution doesn't happen overnight
A million years is a lot longer than we think it is
We wouldn't recognize a key transition while it was happening

Useful to keep these in mind when explaining and /or arguing about how evolution works.

Evolution Is A Tinkerer: Using Homology To Understand How

suvrat_k@yahoo.com (Suvrat Kher) — Fri, 18 Sep 2009 06:46:00 +0000

Here is an evolution link to bookmark. Homology is one of the most fundamental concepts in biology used for comparative analysis and for ferreting out evolutionary relationships. It refers to structures, traits that were present in the common ancestor of related species and which were inherited and since then differently modified in the descendants. The forelimbs of different mammal species although adapted for different functions are homologous since the basic structure was inherited from their last common ancestor.

If we include a wider group of organisms for comparison say the vertebrates and the invertebrates then the limbs of these two groups are not homologous since the last common ancestor of these two groups was limbless. Limbs evolved independently in these two groups. They are analogous structures.

But analogous structures can still be built by genes which are homologous!

Evolution is a tinkerer and uses the same gene networks to build new structures with similar functions in different groups of distantly related organisms.

PZ Myers explains this concept of deep homology and the consequences for understanding how evolution works in an article for Seed Magazine:

Evolution is a tinkerer that cobbles together new functions from old ones, and the genome is a kind of parts bin of recyclable elements. When new features evolve, the parts in the bin are co-opted to operate in new roles. As a result, the same parts appear in anatomically and evolutionarily distinct structures because it is faster and easier to reuse an old gene network that almost does what is needed, than it is to spend another few million years evolving a distinct gene for the function.

This makes these master genes precisely analogous to the stock of goods found in a hobbyist’s electronics store. Standard subunits—oscillators, op-amps, field effect transistors, switches, rheostats, and so forth—will get incorporated into many different kinds of projects; whether she is building a radio or a synthesizer or a burglar alarm, the hobbyist will find it easier to just grab an oscillator integrated circuit off the shelf than to design her own. We could sample devices built by different hobbyists with different purposes, and when we rummaged about in their insides, we would find the same subunits incorporated into novel, larger assemblies.

An important concept - homology- explained elegantly using ...an analogy ...he.. he...

Read the rest here....

Tip: 3QuarksDaily

Imagining An Underground Venice In The American Southwest

suvrat_k@yahoo.com (Suvrat Kher) — Tue, 15 Sep 2009 10:03:00 +0000

From BldgBlog post Hexagonal Hydropolis I went to the source Matsys where Andrew Kudless has created a futuristic and imaginative vision of a subterranean urban landscape in a dessicated American southwest.

The concept and architecture is stunning. Vast underground water reservoirs are connected to the cityscape via canals which also are the means of transport.

Image; Sietch Nevada / renderings by Nenad Katic

This is a grand and impressive outlook and I keep thinking on another track when I come across the many futuristic adaptive scenarios that are being proposed as responses to changing climate and resulting changes to our living space. The problems are varied, deep underground water storage, deep underground CO2 storage, coastal erosion, understanding changing river dynamics in the north Indian plains as glaciers shrink, exploring for uranium to boost nuclear energy....geology and geologists will play an increasingly important role as we explore and implement solutions to meet this challenge.

Relaxing Natural Selection In The Wild

suvrat_k@yahoo.com (Suvrat Kher) — Mon, 14 Sep 2009 07:57:00 +0000

Trends in Ecology and Evolution has a paper on the evolutionary fate of traits that are subjected to relaxed selection. More than the paper I enjoyed the journal cover:

Very Gary Larson..ish I thought.

Science Daily has a good summary of the research.

Undergraduate Degree By Salary: Geologists Not Doing Too Badly

suvrat_k@yahoo.com (Suvrat Kher) — Wed, 09 Sep 2009 07:00:00 +0000

PayScale College Salary Report has published a list of best undergraduate college degree by salary for the United States. Undergraduates who go on to earn a Master's or a PhD are not included in this survey.

Best Undergrad College Degrees By Salary

Methodology
Annual pay for Bachelors graduates without higher degrees. Typical starting graduates have 2 years of experience; mid-career have 15 years. See full methodology for more.

Among the pure sciences, physics, statistics, math and biochemistry are ranked higher but geology comes next with a starting median salary of $ 45,100 and a mid career median salary of $ 84,200.

See the full list here and the methodology here. Tip: Greg Mankiw

Olivia Judson Reviews A New Film On Charles Darwin

suvrat_k@yahoo.com (Suvrat Kher) — Wed, 09 Sep 2009 06:40:00 +0000

Olivia Judson in the New York Times has a nice essay on a new film on the life of Charles Darwin:

Unlike most biographies of Darwin, its central event is not the publication of the “Origin,” but the death of Darwin’s adored eldest daughter, Annie, at the age of 10......

.....“Creation” thus takes on two main themes. The first is the difference in religious outlook between Darwin and his wife — and, more broadly, between Darwin and much of Victorian society. This is inevitable in any account of Darwin’s life. The second, and more unusual, theme is the mental hell of guilt and anguish that the death of a loved one can bring, and how that can fracture a family.

It's always refreshing to come across works that get past being hagiographies of a venerable historical figure and which bring out the human instead.

Richard Dawkins New Book Is Out

suvrat_k@yahoo.com (Suvrat Kher) — Mon, 07 Sep 2009 06:22:00 +0000

A long time back a fan from the U.S gave Richard Dawkins a printed T-shirt titled

Evolution: The Greatest Show on Earth The Only Game in Town. I don't know if that inspired the title of his latest book - The Greatest Show on Earth: The Evidence For Evolution... but...

The U.K edition is out and the U.S edition will be released September 22. Not sure about the India release date.

I doubt anyone from the creationist community will be swayed into accepting evolution but if you are genuinely curious about evolution then this might be as good a book as any to start learning.

Early reviews are positive although a bit uneasy about Dawkins propensity to insult creationists. That's his style. It won't win him new readers of the fundamentalist mindset but then I think he's long given up winning those over.

For the rest as always it promises to be a treat. I really enjoyed his previous book on evolution The Ancestor's Tale and I am looking forward to reading this one.

Maybe not creationists but I am curious to know if Dawkins has made any attempt to win over another disgruntled lot; biologists who complain that Dawkins puts too much emphasis on natural selection and gives too little attention to random genetic drift and chance events as important drivers of evolution. Although he has never denied the role of drift and chance many of his previous books focused on adaptive evolution and so an emphasis on natural selection as an explanation was inevitable.

This book though is titled the Evidence For Evolution and not Evidence For Evolution through Natural Selection and I wonder if he has been more generous in explaining the role of drift as another important mechanism of evolution and how drift can generate recognizable patterns that can be powerful evidence for evolution. One example that comes to mind is mutations that affect non-coding sections of DNA. This portion of DNA since it has no functionality will be invisible to natural selection and mutations will accumulate and become fixed through random drift.

If two species have such identical patterns in the same region of their non coding DNA that is strong evidence of a shared ancestry and a shared evolutionary history. You might argue that a creator would put identical functions in two species but why would He place identical non functional bits in different species. Its a bit like recognizing plagiarism. If you copy the dud parts and mistakes from someone's essay then...

From the early reviews though natural selection still seems to be the only game in town for Richard Dawkins.