Thursday, April 25, 2013

My Criticism Of K.S Valdiya's Paper Published In Current Science

and Valdiya's reply was not satisfactory at all..

To those unfamiliar with the sequence of events:

1) Giosan et al publish a paper in the May 2012 issue of PNAS on fluvial geomorphology of rivers around the Harappan civilization and conclude amongst other things that the Sutlej and Yamuna rivers got diverted from the channels now occupied by the river Ghaggar (Haryana Punjab plains) to their present day course by Late Pleistocene. This meant that the Harappan civilization along the river named Ghaggar -also identified as the Vedic Saraswati by many- was watered by a monsoonal river and not a glacially connected river.,

2) I write a blog post of this paper on June 15 2012. I comment that some Indian geologists working on this problem accepted the scenario of a glacial Ghaggar /Saraswati during Harappan times without critically assessing the evidence.

3) My blog post appears on the Indo-Archaeology forum.  In the confusion due to many cross links my comments about the role of Indian geologists are misattributed to Giosan et al.  Giosan tries to set the record straight. K.S. Valdiya based on his correspondence with S. Kalyanaraman also confuses the source of those comments and misattributes them to Giosan et al in his article in Current Science. Valdiya accuses Giosan et al of diminishing the research of  Indian geologists partly because he misidentifies Giosan et al as the authors of those comments and partly because of Giosan's comment on the Indo Archaeology forum  that they have only referred to 'papers and authors presenting reliable data and facts’. S. Kalyanaraman forwarded this comment to Valdiya who then regarded it as a slight on the work of Indian geologists.
These below are my words that got misattributed to Giosan et al:

A geological narrative constructed without rigorous evidence has been promoted to support a theory of cultural evolution in northwest India.


..  now be revised or at the very least these geologists  need to admit that their theory has been seriously challenged.

4) I write a blog post on the geological problems in Valdiya's Current Science article.

5) Giosan et al protest the misattribution in the Correspondence section of February 10 issue of Current Science.

6) My comments and Valdiya's reply to Giosan et al and my comment published in the April 25 issue of  Current Science.

phew... I didn't know writing a nerdy geology blog will land me in such a controversy! :)

Moving on to Valdiya's reply to my comment I want to elaborate on Valdiya's denial that he misrepresented the work of other authors.

Monday, April 22, 2013

Review Article: Recurrence Of Great Subduction Zone Earthquakes

Open Access in Current Science

Kusala Rajendran

The last decade has witnessed two unusually large tsunamigenic earthquakes. The devastation from the 2004 Sumatra–Andaman and the 2011 Tohoku-Oki earthquakes (both of moment magnitude ≥ 9.0) and their ensuing tsunamis comes as a harsh reminder on the need to assess and mitigate coastal hazards due to earthquakes and tsunamis worldwide. Along any given subduction zone, megathrust tsunamigenic earthquakes occur over intervals considerably longer than their documented histories and thus, 2004-type events may appear totally ‘out of the blue’. In order to understand and assess the risk from tsunamis, we need to know their long-term frequency and magnitude, going beyond documented history, to recent geological records. The ability to do this depends on our knowledge of the processes that govern subduction zones, their responses to interseismic and coseismic deformation, and on our expertise to identify and relate tsunami deposits to earthquake sources. In this article, we review the current state of understanding on the recurrence of great thrust earthquakes along global subduction zones.

The figure above shows the  Cascadia subduction zone, Pacific coast of N. America (source Rajendran 2013) . I looked through the Reference section and saw a number of recent papers addressing both the evidence for past earthquakes as well as the impact of the 2004 Sumatra earthquake on the Indian coastline. The acknowledgements indicate funding for this paper from the Ministry of Earth Sciences, Govt. of India. Its good to see basic geological research into subduction zone earthquakes being supported this way.

Wednesday, April 17, 2013

On The Use Of The Word Archaic In Writing About Evolution

In an interesting article on hybridization in human evolution in Earth Pages by Steve Drury I came across the following sentence:

Multi-regional evolution posits archaic populations  originally living in and outside Africa being  gradually assimilated by migration and interbreeding that transferred modern traits everywhere yet retained some regionally distinct features of the archaic groups. The first model clearly has to be modified as evidence accumulates for some degree of hybridisation with archaic groups outside Africa. The second of the two pre-genome ideas seemed to be rendered obsolete by the DNA evidence for significant interbreeding between early immigrants from Africa and Eurasian and Asian populations of earlier archaic migrants – Neanderthals and Denisovans respectively – whereas modern Africans show no sign of recent contact with these archaic groups. However, not all regions of the genome have been examined for signs of more universal hybridisation.

What meaning should one read into the term "archaic". A common misconception is that archaic means "less evolved".  But when migrants from Africa came in contact with Neanderthals or Denisovans or some other unnamed human population, it was a meeting between two human populations who had been evolving for the same amount of time since their divergence from a common ancestor. So there is no sense in saying that one group was less evolved than the other.

So then,  archaic could mean that at the time of contact one population was resident in the area for a long period. They were early migrants into that area, making them an old population. Or, archaic could mean that one population had been isolated from the common gene pool for a longer period of time than the other, meaning, one population branched off much earlier from the ancestral population.  The branching event could have been a migration resulting in genetic isolation. Or, archaic could mean that one population resembled the common ancestor more than the other population i.e. it had retained many ancestral traits and had undergone less morphological changes, while the other population had accumulated more new morphological traits since diverging from an ancestral population. In all the above three, the term archaic could well be used to describe a living population. Lastly,  archaic could be used to describe features that are now extinct.

When "modern" humans migrating from Africa met Neanderthals in Europe, they were not meeting  people who were less evolved , but people who had been evolving along a different trajectory for as long as any other then living branch of humans. We think of the jutting brow ridges and barrel chest of Neanderthals as archaic because that trait is no longer visible or very rare in humans living today. We see it only in fossils. They are features of antiquity.

But at the time "modern humans" met Neanderthals there was no archaic or modern in the sense of less or more evolved. Neanderthals were archaic in the sense that they were the earlier residents of Europe and had been genetically isolated from African populations for a long time. Both populations had some archaic traits in the sense of traits retained from their ancestors. Both also had changed morphologically, having evolved some new traits since their divergence from a common ancestor.  There was no way of knowing then which collection of traits would survive till today to be categorized as modern and which would be consigned to archaic in the sense of being extinct.  At that time they were just two sibling populations with their own unique evolutionary histories.

Tuesday, April 16, 2013

Science Proceeds By Funerals

Above all, science is a human institution. And as a machine for thinking, it's greater and more powerful than any of its single participants. You said that science proceeds by tiny steps. It also proceeds by funerals.

University departments are just waiting for the professor to get out of the way so the younger guys can get in.

That was author Ian McEwan on a very listenable hour of Science Friday on the importance of science writing in science books as well as science in fiction. The other guests were cosmologists Brian Greene and Lawrence Krauss.

I thought Ian McEwan gave a really good account of why he includes science in his books:

FLATOW: Ian, why do you put science in your books? What - why do we have to know about quantum mechanics? Are you purposely doing that to teach us something or just to...

MCEWAN: No, absolutely not. No.


MCEWAN: It just came along with the character. It's a reflection of my own pleasure in it, but it seems just a human enterprise. I mean, this is - I mean, the standard measure of how alive you are is the measure of your curiosity, and I think of science as organized curiosity.

We once relied on priests to tell us the shape and nature and purpose of the cosmos and life itself. It's been a long, slow story of that undoing. We now have a far more interesting story, and it's also penetrated our lives. I mean, there's climate change, and we all have these intricate, beautiful machines in our hands, and it's impacting on our decisions about bioethics and many other things.

So if we think of the novel as an investigation of the human condition, technology and science is now so woven into that condition. You cannot escape it. So it's inevitable, I think, that...

Download / Transcript

Monday, April 8, 2013

Paranoia Over Google Mapping Tools Persists In Indian Officialdom

sigh... I keep writing about this only partly as comedy.. but mostly in frustration...

From an article in the Hindu about the recently held "mapathon"contest organized by Google.

As Delhi Police investigates whether Google violated rules in holding a competition that asked users to add information about their local areas for its online map, the U.S. Internet giant on Saturday said it had responded to queries raised by Survey of India more than 10 days back and hasn’t heard from it yet. (emphasis mine)

Apparently, the Survey of India and the Defence establishment is worried that such initiatives will have grave security repercussions.  The problem is that Google has been asking users to add information about their local areas for its online map for several years now. I just don't comprehend how a mapping contest wherein lots of enthusiasts add places of interest on a map within a short span of time becomes a greater security threat than an individual using Google Maps on any other day of the year.

more from this article in the Economic Times... But on behalf of the Surveyor General of India Swarna Subba Rao, his deputy major general R C Padhi told the three ministries that Mapathon was "not in accordance with the national Mapping Policy 2005 and map restriction policies issued by the defence ministry from time to time", sources said.

Added a senior defence officer, "Such activities can have serious security repercussions in case mapping of restricted areas is undertaken by members of the general public."

The words "general public" come out of the mouths of our officials with such contempt and suspicion. These archaic mapping policies which restrict the "general public" from mapping certain areas have long been rendered meaningless by the many roving eyes that hover above the earth. I am sure the government understands this.. but relinquishing control over anything has always been hard for Indian officialdom.

The exceedingly vast majority of people using Google applications to map India don't want to harm India.

Those who do... might I remind the Indian Government that the terrorists who attacked Mumbai on November 26 2008 did not wait for a mapping contest to survey the city.

Friday, April 5, 2013

Biogeography And Teaching Evolution

Joshua Rosenau of the National Center for Science Education, Oakland, CA, USA has a wonderful essay in Evolution: Education and Outreach on how observations of the bio-geographic distribution of species helped Darwin and Wallace to work out independently their theories of evolution through natural selection.

He suggests that many of  today' students who are often reluctant to accept evolution because they see differences between species as unbridgeable gaps can overcome this obstacle by observing the actual patterns of differences between closely related species living amongst them.

From the article:

The greatest challenge many students face in understanding evolution is what Wallace faced in 1846: they haven’t seen the sort of diversity that calls for explanation in terms of evolution. The world most students encounter seems to contain organisms in discrete categories: squirrels and rabbits, robins and sparrows, grass and daisies, oaks and pines. They are unlikely to notice that two ladybird beetles actually represent different species or that there are several species of grass in their lawn, let alone to recognize that there are two local species of chipmunk which can only be distinguished by dissection or DNA analysis. What diversity they notice represents groups that are quite distinct, with differences so large that it is impossible to imagine how their members could share a common ancestry.

As a result, students today, much like Darwin in 1835, tend to see species as distinct entities. Presenting students with a similar experience of the often subtle differences between species can similarly shake this misconception. When they realize how low the barriers can be between different species, they can place lessons on speciation in a more accurate context. Rather than imagining that speciation means turning lions into tigers, or bears into cows, or fish into humans, they will see that speciation involves a subtle divergence in the evolutionary trajectories taken by populations. Because the Galápagos mockingbirds were still early in their divergence, Darwin was able to recognize the process. Students today can learn similar lessons by examining the subtle differences between species on neighboring islands. The Evolution and Nature of Science Institute has a lesson plan in which students compare lizards in the Canary Islands (, while Understanding Evolution offers a lesson plan looking at Anolis lizard biogeography in the Caribbean (

Very relevant advice but applicable only to those students who are willing to examine the evidence with an open mind. People indoctrinated with a fundamentalist ideology are unlikely to be impressed by two very similar species of beetles in their backyard. .

By the way this journal,  Evolution: Education and Outreach is now open access.

So dip into it.

Thursday, April 4, 2013

Lessons In Carbon Storage From Geological Analogues - Open Access Geology

Mike Bickle and Niko Kampman in an open access article in the April issue of Geology summarize the findings of two papers (1 , 2)  published in the same issue on naturally occurring CO2 accumulations in sedimentary reservoirs and inferences drawn on their long term fate.

One potential strategy to manage growing atmospheric CO2 is to inject and store it in deep sedimentary aquifers with a retention time of at least ten thousand years.

The article identifies the key questions:

(1) how quickly will the buoyant CO2 dissolve in formation brines (good), (2) how quickly will the CO2 brines react with silicate minerals and precipitate solid carbonate phases (good), (3) will CO2 or CO2-charged brines corrode cap-rocks and escape upward (bad), and (4) will CO2 penetrate up fault zones (bad)?

It is dense but rewarding reading for those into mineralogy, phase equilibria and fluid-rock interaction. 

This is something that should be of enormous interest to Indian sedimentary basin specialists and climate change mitigation planners. In a recent post I mentioned about India's plans to build 400 odd more coal power plants in the next few decades. Many will be located near sources of coal in the continental rift basins of eastern India. Is carbon dioxide sequestration in natural reservoirs economically viable? Do these basins have favorable conditions deep underground for long term storage of CO2? It is research well worth funding given that our dependance on coal will last several more decades.

Tuesday, April 2, 2013

Huh? Thousands Of Rivers Wiped Off Map Of China

The first national water census pointed out that thousands of rivers (28 thousand was the figure given) shown on previous maps are now missing from China' s state water maps. See this article.


Official- Climate change is to blame for the drying of some waterways. Plus some earlier mistakes by cartographers

Environmentalists: Ill conceived development and over use of underground water resources.

That last one is an important point. Much of the base flow of rivers, especially those which are not sourced from glaciers comes from groundwater discharging as springs. That means the water you see flowing in the river channel months after the rains are over is actually groundwater seeping out along river banks. Even rivers connected to glaciers may have a significant component of their flow provided for by groundwater discharge. A survey in the Nepal Himalayas revealed that groundwater contributes more than melting glaciers to the annual discharge of the rivers. 

Rivers may gain water from groundwater over long stretches. Such streams are called effluent (fig on left: source: USGS) . Rivers that lose water to groundwater are called influent.  Here is an excellent USGS  primer on the impacts of groundwater exploitation on surface water.

All the important monsoonal rivers in Peninsular India as well,  Narmada, Mahanadi, Cauvery, Krishna and Godavari depend on groundwater discharge to remain perennial. If the local water table plummets well  below the river bed due to over extraction of groundwater then discharge into the river will cease.

River management must include management of groundwater resources as well. The USGS article I linked to points out: " From a sustainability perspective, the key point is that pumping decisions today will affect surface-water availability; however, these effects may not be fully realized for many years".

A lesson not taken seriously in China and in India as well.