Friday, December 20, 2013

A Basalt Trek Geo-Haiku

on a high plateau
jagged basalt Cretaceous
curious travelers walk

and a friend sent in this one -

through windswept fields
we tread on dead volcanoes,
A gentle dog follows

- Sushma Date

Monday, December 16, 2013

Porphyry Copper Deposits And Tectonic Plate Thickness

Just a follow up to my earlier post on porphyry copper deposits with an example from the Malanjkhand mines of Central India.

Nature Geoscience has a paper on the relationship between copper deposits and magmatic arc thickness. The full paper is behind a pay wall but the abstract is helpful enough:

Porphyry copper systems supply about 75% of the world’s copper. They form above subduction zones and are preferentially associated with calc-alkaline magmas. Such magmas result from continuous iron depletion during differentiation, in contrast to tholeiitic magmas that show initial iron enrichment during differentiation. The formation of calc-alkaline magmas is favoured by high water content and oxygen fugacity. These characteristics, as well as magmatic metal contents, are thought to be imparted in the mantle source by fluids of the subducted slab. Yet this process does not explain why porphyry copper systems preferentially occur in thicker arcs. Here I present a statistical assessment of more than 40,000 published geochemical analyses of magmatic rocks from 23 Quaternary-aged volcanic arcs worldwide. I find that magmas of thicker arcs are systematically more calc-alkaline and more depleted in copper than magmas of thinner arcs. This implies that the missing copper in the former accumulates as copper sulphides within or at the base of thicker arcs. Such copper accumulations are an essential step in forming porphyry systems. These results suggest that the thickness of the overriding plate provides a more important control on magma differentiation than the composition of the mantle source, and can explain the preferential association of porphyry copper systems with calc-alkaline magmas and thicker arcs.

Malanjkhand ores would have around 2.4 billion years ago been a copper enrichment at the base or at the deep levels of a magmatic arc system in a subduction zone setting as smaller cratonic blocks converged. The roots of this ancient magmatic arc mountain chain has since been exhumed due to subsequent tectonic movements and erosion to reveal its riches.

Sunday, December 8, 2013

Sunday Humor: Rugby And Geology Don't Go Together

I ran into a friend after many years. Her son used to come to our academy for soccer and rugby coaching. She mentioned that a common friend had recently put up a link to my blog on his Facebook wall and after reading a few of my posts had showed my blog to her son, reminding him who I was.

Her son who is now a teenager exclaimed.. "but Mama how is it that a rugby coach can be clever enough to write a geology blog?"

My friend is now trying to persuade her son to meet me again. I on my part have promised to take him and his friends to a trip to the local geology museum.

Maybe I can convince him that sometimes sports, jocks and rocks do go together.

Tuesday, December 3, 2013

A Dispute About Adam And The Origins Of Humans

More than 40% Americans insist that God created humans in their present form less than 10,000 years ago. Probably a majority don't believe evolution at all or accept that it has played a role but one overseen by God in the history of life.

Now genetics is throwing up another problem for creationists to chew on:

Lexington writes in the Economist -

A trickier controversy has been triggered by findings from the genome that modern humans, in their genetic diversity, cannot be descended from a single pair of individuals. Rather, there were at least several thousand “first humans”. That challenges the historical existence of Adam and Eve, and has sparked a crisis of conscience among evangelical Christians persuaded by genetic science. This is not an esoteric point, says Michael Cromartie, an evangelical expert at the Ethics and Public Policy Centre, a Washington think-tank: many conservative theologians hold that without a historical Adam, whose sin descended directly to all humanity, there would be no reason for Jesus to come to Earth to redeem man’s Fall.

Academics have lost jobs over the Adam controversy. Many Christian universities, among them Wheaton (a sort of evangelical Harvard and Yale, rolled into one), oblige faculty members to sign faith statements declaring that God directly created Adam and Eve, the “historical parents of the entire human race”. John Walton, an Old Testament scholar at Wheaton, suggested that Adam and Eve are presented in Genesis as archetypes, though he called them historical individuals too.

Read the rest here.

Sunday, December 1, 2013

Sunday Image: Cavity Minerals In Basalts

In cracks, fractures, geodes, gas vesicles of the Deccan Basalt lava flows occur secondary minerals of the zeolite family along with silica, calcite, apophyllite and iron hydroxides. They are often breathtaking in their fully faceted form and gorgeous color combinations.

Green apophyllite is one of the most common and appreciated minerals. I say mineral but really apophyllite is a general term used for three different minerals, fluor-apophyllite, hydroxy-apophyllite and natro-apophyllite. Most of the Deccan Basalt apophyllite are fluor- and hydroxy apophyllites. These specimens have a peculiar form. Their name is derived from the Greek apophylliso meaning "it flakes off". They have a basal cleavage like the micas which lends it to being easily split along one plane of weakness but an overall crystalline structure conforming to a tetragonal symmetry.

Here it is in the picture below growing like a creeper of other worldly kryptonite from a lustrous crystalline bed. 

The large off white crystals at the base of the geode are also apophyllite.  Zoom in and you will see large fleshy pink colored sheafs of stilbite clinging to the wall of the geode. The other minerals not easily recognizable are calcite, quartz and heulandite.

Source: The Gargoti Museum

Wednesday, November 27, 2013

On The Source Of Orogenic Gold

Interesting!... In the Research Focus section of Geology Andrew G. Tomkins writes about  (open access) the current state of understanding on the sources of orogenic gold deposits. These are deposits formed in accretionary and collisional orogens where two tectonic plates are pushing against each other.

On the source of gold in such settings:

There are two plausible sources for the gold: (1) metamorphic rocks, from which fluids are generated as temperatures increase; and (2) felsic-intermediate magmas, which release fluids as they crystallize. Gold-bearing magmatic-hydrothermal deposits are enriched in many elements, including S, Cu, Mo, Sb, Bi, W, Pb, Zn, Te, Hg, As, and Ag (e.g., Goldfarb et al., 2005; Richards, 2009). Such deposits have been referred to as gold-plus deposits (e.g., Phillips, 2013), but most orogenic gold deposits fall into the alternative group of gold-only deposits, and are more enigmatic. These are characterized by elevated S and As, and have only minor enrichments in the other elements. The current dominant opinion is that metamorphic rocks are the source for these deposits (Goldfarb et al., 2005; Phillips and Powell, 2010). 

And on the major gold forming episodes in earth history, wherein several geological situations converged to create conditions suitable for orogenic gold deposition:

The vast majority of orogenic gold (excluding Witwatersrand, South Africa) is from three periods in geologic time: the Neoarchean (ca. 2700-2400 Ma), a second period in the Paleoproterozoic (ca. 2100-1800 Ma), and a third period from ca. 650 Ma continuing throughout the Phanerozoic (Goldfarb et al., 2001). Two explanations have been offered for this timing: (1) because orogenic gold deposit formation requires accretionary tectonics, the major periods of formation coincided with periods of continental growth (Goldfarb et al., 2001), and (2) during the Phanerozoic, increased ocean oxygenation facilitated uptake of gold in biogenic and diagenetic pyrite, which became the gold source during later accretion and metamorphism (Tomkins, 2013). The first explanation must be correct to some extent, but cannot explain the relative lack of gold during the formation of Rodinia; the second requires that gold can be sourced from carbonaceous metasedimentary rocks.

This open access commentary is written as an accompaniment to a paper by Gaboury 2013 in the same issue which identifies ethane C2H6 as a diagnostic geochemical tracer sourced from carbonaceous metasedimentary rocks, a common component in subduction accretionary settings.

In more local news from India, gold mining in the Kolar mines from Karnataka state is set to resume. The mines are located in the 2600 mya greenstone belts, which are composed of greenschist and lower amphibolite facies mafic and felsic volcanic rocks intruded by plutons. These Archean greenstone belts are thought to originate in either ocean spreading centers or island arc settings which later got accreted (plastered) on to continental nuclei during orogeny. The major metamorphic minerals are green colored chlorite and amphiboles, hence the name. Gold occurs in quartz veins and all the geological indicators point to them sourced from magmatic fluids derived predominantly from the crystallization of felsic magmas i.e. source (2) of the orogenic style deposits detailed in the article.

Thursday, November 21, 2013

Quote: John McPhee On The Left Handed Geologist

I was flipping through John McPhee 's Assembling California and came across this passage:

Gradually, though - outcrop to outcrop, roadcut to roadcut - Moores revived enough related scenes in the distinct origins of the random rock to frame a cohesive chronological story. That is what geologists do. " You spend a lot of time working over rocks and you have a lot of time to do nothing but think," he said. "These mountains , for example are Tertiary normal faulted, confusing topography with regard to structure. They show different levels of structure in different places. To see through the topography and see how the rocks lie in three dimensions beneath the topography is the hardest thing to get across to a student". After a mile of silence he added cryptically, "Left -handed people do it better". 
I said nothing for a while, and then asked him, " Are you left-handed?"
He said. "I am ambidextrous".
As it happens, I am left-handed, but I kept it to myself. 

I am also left handed... True or not, that lefties are disproportionately represented in the geology profession has been the subject of discussion before.. I am so glad that one of the great writers about geology is left handed too..

Thursday, November 14, 2013

What A Porphyry Copper Ore Body Tells Us About How India Was Assembled

Nature Geoscience has some interesting articles on giant magmatic ore deposits  ( 1 , 2 ) with a focus on porphyry copper- molybdenum deposits which occur within magmatic arcs above subduction zones.

Ever since I found that copy of Tyrrell I've been reminiscing a bit about my early days in geology. These papers on copper ores started another chain of thought. We were preparing for our first year M.Sc. field trip which is really supposed to be a tour to learn field mapping. So the area selected is usually one where rock bodies are exposed clearly, have lateral continuity, where relations and contacts between geological units can be observed, basically an area where principles of field mapping are relatively easy to learn. As it happens our department at Pune University had gotten a big grant from ONGC to do a reconnaissance of Gondwana rift basin sediments of Carboniferous-Permian age just north of Itarsi in Madhya Pradesh. Our department chair organized our field trip to this area, reasoning that we could use this for training as well as contribute to the project.

Unfortunately, it was a disaster. The area was thickly forested, rock exposures limited to few stream cuttings and occasional road cuts, just not what you want for a rigorous training in mapping. The one bright spot was the copper mine we visited at Malanjkhand. This is an open pit mine.

Google Interactive Map of Malanjkhand Copper Mines:

View Larger Map

We were allowed to walk right up to the exposed walls of the pit and observed the stringers of copper and molybdenum sulphide ore embedded in networks of quartz veins. The host rock was a granodiorite. It was altered to various clay assemblages but you could make out blobs of relatively unaltered textures. Overall, after two weeks of tramping through forests it was great to be looking at massive walls of rock and glistening ore!

Ok, so what does this copper ore body have to do with ideas of how India was assembled and what does that even mean?

Monday, November 11, 2013

Not Just a Puppet! The Animated Life Of Alfred Russel Wallace

Have you seen this documentary?

The Animated Life Of A.R. Wallace.

Produced by Flora Litchman and Sharon Shattuck and narrated by George Beccaloni of the  Natural History Museum London and Andrew Berry of Harvard University, it celebrates the life and work of Alfred Russell Wallace who along with Charles Darwin discovered the principles of evolution through natural selection in the mid 1800's. Wallace also made pioneering contributions to the field of Biogeography.

A fine example of creative science outreach using paper puppet animation. Beautifully produced and narrated.

Thursday, November 7, 2013

Reliance Cites Geological Surprises In Krishna Godavari Basin

My friend S.C.N Jatar, former CMD Oil India and ONGC Videsh writes about the suspicion that Reliance overstated reservoir potential in the KG -D6 field of the Krishna Godavari basin.

“Geological surprise” is cited as the cause of Reliance’s production shortfall. KG-D6 block commenced production in September 2008 with 0.58 million standard cubic meters per day (mmscmd) reaching a peak of 69.43 in March 2010 and then declined to 13 mmscmd currently. Reliance attributed the decline to substantial variance from prediction in reservoir behaviour, higher than envisaged pressure decline and unpredicted early water production in some wells. Was there a geological surprise? In an article published 10 years ago in Business Standard on January 13, 2003, I wrote, “Producing even 40 mmscmd for 10 years will need an unusually large number of wells....” The latest thinking on such reservoirs is that one can expect unpleasant surprises even after 3D surveys confirm the ‘structure’ because it cannot confirm the ‘reservoir’. I had then stressed: “There is a big question mark over the projected recoverable reserves of the Dhirubhai fields.”

Rest of the article here

Tuesday, October 29, 2013

What Disease Did To Europe

From The Economist : Plagued by dear labour

Most of the article is about a debate on whether the population crash due to the plague outbreaks in the mid 1300s Europe brought about real improvements in wages and labor rights.

and then this speculation:

A more speculative theory suggests that the Black Death encouraged Europeans to become more imperialistic. Prior to the Black Death, Europeans were rather averse to long sea voyages, given the extremely high death rates on boats. But as death rates on land soared, people became less afraid of sea travel; it was not much riskier than staying at home. As a result, colonialism was kick-started. Mr Belich links the plague to the “spread of Europe”.

Interesting-- i would think the more immediate reason that triggered widespread European exploration and imperialism was a desire in Christian Europe to break the Muslim domination of Indian Ocean and Arabian Sea merchant routes. With this disease theory one can argue that it was high death rates on land that made Europeans get over their timidity of sea voyages.  Another factor is that advances in ship building made long voyages less risky and produced ships big enough to make voyages profitable. Dom Henrique (better known as Henry the Navigator) the younger son of the King of Portugal in the early fourteen hundred's was asked to find a land route across the Sahara to break the Muslim bottleneck on the Red Sea and Persian Sea routes. He realized the foolishness of this venture and began collecting navigation charts of the African coasts and became a patron of ship builders. That subsequently led to explorers like Batholomew Diaz and Vasco De Gama to finally round the Cape of Good Hope and find a passage to India and the East Indies spice riches.  Again with this disease theory one can argue that disease and the population crash triggered innovation in general and one result was advances in ship building!.. so you can end up putting the disease theory at the root of any complex causal chain and explain all sorts of intangibles with it.. that makes me wary..

Wednesday, October 23, 2013

Early Homo- One Species Or Many?

A paper analyzing the variation in morphology in early Homo fossils from Dmanisi Georgia dated to about 1.8 million years ago and further encompassing East African samples too has created quite a stir. The authors conclude that the range and pattern of variability in the samples suggest that all these early Homo fossils - previously named as Homo habilus, Homo erectus, Homo rudolfensis - represent one variable species. Early Homo did not branch off into new species, rather it is one lineage.

If you want to go beyond the more sensationalistic reporting of how this changes "everything" read these two posts-

1) John Hawks - A perspective on the single species hypothesis for early Homo and what it might be really telling us about evolution, migration patterns and population characteristics of our ancestors.

2) Adam Van Arsdale- What the Dmanisi sample tell us about variation in species and how best to interpret it in the fossil record.

Thursday, October 17, 2013

Lunar Cycles And Groundwater Level Fluctuations In Confined Aquifers From S. India

Interesting paper in Current Science (Open Access) - Impact of Earth’s crustal tides on groundwater regime in confined sedimentary aquifers of Andhra Pradesh, India - Umamaheswara Rao Bollimunta

Water being less rigid deforms more easily due to the Moon's and Sun's gravitational attraction, manifested as the familiar ocean tides. However, the earth's crust too deforms slightly. So, there are crustal tides daily just like ocean tides. The magnitude of deformation is quite small, about 2 feet across the diameter of the earth. U.R. Bollimunta in this paper demonsrates that water levels in two piezometric wells i.e. wells which puncture confined aquifers show cyclical variations in water level tracking lunar phases. When the moon's pull is the strongest as on full moon the water levels drop. This is because when the moon's tidal attraction is maximum the overburden load on the aquifer is reduced allowing it to expand every so slightly.  During times of less lunar attraction the aquifer compresses causing water levels to rise again.

Fascinating stuff-


Signatures of the Earth’s crustal tides are recorded in the groundwater regime, particularly in confined aquifers in the form of rise and fall of its piezometric surface. Though this phenomenon is universal, and exists in the entire groundwater regime, the recording at a few places and in some rare situations is doubtful. An attempt is made here to study the conditions required for recording this phenomenon along with its basic principles. The Central Ground Water Board has constructed 115 piezometer wells and monitored piezometric heads with high frequency digital water level recorder. The impact of Earth tide on ground- water regime is clearly recorded at two sites namely, Kothagudem (Khammam district) and Mangapet (Warangal district). The wells at these sites are constructed in the confined aquifer of Kamthi sandstone in Godavari valley which is nearly 200 km inland from the east coast. Analysis of the data reveals that the piezometric level heads fluctuate in a cyclic manner and the variations for each lunar cycle of 13–14 days with high peaks on new Moon and full Moon days. The peaks observed in the piezometric heads gradually decline coinciding with the lunar phase. Distinct changes in piezometric heads are observed for each phase of the Moon in both of the above-mentioned places. An account of impact of lunar and solar attraction forces on piezometric level heads of ground- water, the ideal conditions required for recording this phenomenon along with a comparison of these hydro- graphs with examples from the literature are provided in the present study.

And No Astrologers.. this slight crustal expansion and compression does not cause big earthquakes.

Monday, October 14, 2013

Giosan Et Al Reply To Valdiya's Article On The Sarasvati River

You may recall this controversy which I detailed in an earlier blog post. A quick recap. A paper in PNAS by Giosan et al in May 2012 presented the results of geomorphological analysis of the Haryana and Punjab plains and concluded that there was no glacially fed rivers flowing through this region during the Holocene. This meant that the Harappan civilization in this region was being sustained by a monsoonal river system, the remnants of which is known today as the Ghaggar, identified by some as the river Sarasvati described in the Rig Ved.

Prof. K.S. Valdiya a very senior Indian geologist did not like this conclusion. Moreover, he felt that Giosan et al have not paid due respect to the work of Indian geologists working on the problem of ancient river systems of this region. He wrote a highly emotional article in Current Science in which he misattributed sentences which I had penned on my blog to Giosan et al and also misrepresented (in my opinion) the work of Giosan et al and other workers.

Both Giosan et al and I complained about the misattribution to Current Science to which Valdiya gave brief unsatisfactory replies.

Now Giosan et al have published a second reply in which they clarify the scientific queries that Valdiya had raised.

Here it is - Open Access.

I find it puzzling that the original paper came out in PNAS, but Valdiya chose to comment and complain - not as tradition expects in PNAS - but in Current Science.

He also has not replied to Giosan et al's second clarification.

Monday, October 7, 2013

Found It! Memories Of Early Days Of Geology Education

A mouse got in to an old book shelf a few days ago. Panicky cleaning up ensued and there from the back out came a treasure.. (not the mouse.. it ran away)

This well worn copy of the Petrology classic was my introduction to rocks when I started taking geology classes during my first year B.Sc. The book written in the late 1920's was still being used in the mid late 1980's and early 1990's! There were about a hundred of us packed in the intro geology class with the instructor drawing rough sketches on the black board and explaining the basics of the interior of the earth and the three primary types of rocks, igneous, sedimentary and metamorphic.

I quickly gave up of Tyrrell and turned to other sources.. but those afternoons I do remember.. I knew that after two years of high school not knowing what I was going to do in life that I was on to something special. Geology has stayed with me ever since.

My decision to take up geology had interesting reactions from family and friends. My immediate family, mom, dad, sister and my grandfather completely supported me. Others were less convinced. I was not very good at math so engineering was out. I was not very good at biology so medicine was out. These two were the prestige courses for students.. they had high social standing and these degrees lead to high income careers. Taking a degree in pure sciences was basically admitting that you hadn't done well in the exams and thus could not hack it in the tough technical degrees.

Getting a B.Sc was for the duffers. But my relatives could not say that to me. So they were very sweet about it.." Geology?.. Yes you should take it.. someone has to do it..  we need oil.. minerals"... blah blah blah..

This condescending attitude continued until I got a scholarship to go to the U.S. Then snobbery took over. Getting scholarships to the U.S was again something that mostly only students from technical colleges like the IIT's were supposed to be successful at. Suddenly I was on par with them. Support for me was now because I had at last brought some prestige to the extended family.. "my nephew got a scholarship to the U.S... for a PhD"..

That I had really become passionate about geology and it meant to me more than scholarships and going to the U.S. completely escaped them.

Friday, October 4, 2013

Quote: John Dewey On The Armchair Geologist

John Dewey in his review of Colliding Continents - a book about the geological evolution of the Himalayas by Mike Searle has these harsh words-

Reading a book like this makes one realise how shallow and limiting is the pseudo-geology done by those who sit in front of their computers composing drivel. As Francis Pettijohn remarked, ‘the truth resides in the rocks’ and that ‘there is nothing as sobering as an outcrop’. This work is a useful lesson to those who are not prepared to sweat and get tired and dirty and try to find out the message of the rocks.

Hard to argue against - but computer modeling when the inputs are acquired through hard fieldwork is a powerful tool to understand geological processes. John Dewey refers to the idea of middle crustal extrusion in Himalayan mountain building. This idea suggests that the rocks making up the High Himalayan Crystalline Series were initially a weak viscous middle crustal layer sandwiched between a strong upper crust and a strong mantle. These soft crustal rocks formed during the India-Asia collision and then were squeezed southwards and as denudation started removing the upper crust were extruded i.e. brought to the surface from underneath Tibet. This idea to be refined and to mature has required all possible ways of understanding the earth- fieldwork, high tech geochemistry, geophysical survey and .. yes... the computer geek... doing mathematical modelling.

Tuesday, September 24, 2013

Quote: Robert Folk On Microbiota and Carbonate Petrology

JSR Paper Clips in a look back 20 years ago features an important paper by Robert Folk, carbonate sedimentologist par excellence, on SEM imaging of bacteria and nanobacteria in carbonate sediments and rocks.

..he says: “the minute interface between bacteria and carbonate petrology may be lilliputian in scale but are conceivably gargantuan in importance….”

Folk was probably moved in to making this utterance by a scene like the one below

These are layered dolomite strata of Triassic age from the Alps.  Folk argued that bacteria and nanobacteria have catalyzed the precipitation of such enormous thicknesses of carbonate minerals on the sea floor right through geologic history.

Many carbonate sedimentologists today do acknowledge that microbes play an important role in carbonate mineral precipitation but the details of the geomicrobiology i.e. exactly what physiological and chemical reactions enhance this precipitation is still being worked out. My recent post on this topic explores the role of microbes in dolomite formation.

It's not often you get to witness seminal breakthroughs in science. I now count myself lucky that I was present at the talk at the 1993 GSA meeting in Boston when Robert Folk described this hypothesis of bacterial influence on dolomite precipitation... 20 years on his argument is withstanding the test of time.

References: Folk, R. L., 1993b, Dolomite and dwarf bacteria (nannobacteria): Geological Society of America Abstracts with Programs, v. 25, p. A-397.

Thursday, September 19, 2013

Flood Risk Assessment Of River Kosi And Disaster Management

From Geology  Pre-Issue Publication

Exploring the channel connectivity structure of the August 2008 avulsion belt of the Kosi River, India: Application to flood risk assessment- R. Sinha, K. Gaurav, S. Chandra and S.K. Tandon

The August 2008 avulsion of the Kosi River, northern India, resulted in a maximum eastward shift of >100 km and created an avulsion belt of 2722 km2. Based on A.D. 2000 Shuttle Radar Topography Mission data and on 2005 Landsat Thematic Mapper satellite image–derived channel network (pre-avulsion), we use a topography-driven connectivity model to simulate the avulsion pathway, which corresponds, to a large extent, to that observed in the post-avulsion period. We then use this model to postulate the avulsive course of the river from another upstream point based on avulsion threshold analysis. Our results demonstrate that this model has the potential for postulating the path of an avulsive channel, and can provide a priori information on the areas likely to be flooded following an embankment breach. 

The Kosi flood and channel shifting in 2008 absolutely devastated large extents of Bihar, so this kind of research is urgently needed. The problem is that it may sit within the confines of a small number of geomorphology experts and not make its way to people who draw up disaster management plans. As geologist K.S. Valdiya not so far back lamented, geology and geologists have not found their way or have not been invited to sit in position that can influence policy.

Sometime despite explicit warnings from geologists, government apathy is to blame. Take the recent flash floods and destruction of Kedarnath town in the High Himalayas. Its not that geologists were unaware of the danger. A recent documentary on National Geographic interviewed many geologists who expressed little surprise at the extent of damage done by the floods. The combination of steep Himalayan slopes made up of foliated fractured rocks, glacial debris, moraine blocked lakes that could breach and overflow and narrow valleys where precipitation and stream waters get focused and funneled into raging torrents makes for an elevated risk of landslides, debris flows and floods during heavy rains.

Ignoring all advice government authorities turned a blind eye as the town of Kedarnath made up of often flimsy substandard construction mushroomed unplanned unregulated in the narrow river bed and floodplain of the Mandakini river. That is inviting catastrophe and nature at some point will oblige.

Monday, September 16, 2013

Field Photos: A Trek To Tikona Fort

Come September I am heading out again in the Deccan Basalt landscapes. Last Saturday I went for a day trek to Tikona Fort, about an hour and half drive from Pune on the backwaters on the Pavana dam.

An interactive map of the Tikona Fort area

View Larger Map

Monsoon clouds hover over the summit

Tuesday, September 10, 2013

Geopathic Stresses Behind Indian Expressway Mishaps

Ok..something lighthearted.. but this really was published as a serious article in the newspaper DNA:

Geopathic stress or simply “bad energies” are harmful radiation arising from the depths of our planet. According to geophysicists, there is a natural magnetic field on the earth’s surface to which all beings are acclimatised. Geopathic stress arises when this natural magnetic field of the earth is distorted by weak radiations generated by underground streams of water, sewers, drains, certain mineral concentrations, fault lines and underground cavities. This stress impact on the physiological condition of drivers leading to critical errors while driving. However, awareness about the existence of this factor can help drivers, experts say.

... Tyres bursting at this spot are the cause of a major number of accidents. The stretch has numerous cracks in the road, which are affecting vehicles. These cracks are due to hollow spots, which are generated due to tectonic movements and cannot be repaired by re-tarring, the earth at these high geopathic stress spots shifts periodically in intervals.

An explanation by people who dabble in Vastu.. which studies among other things the "energy" being emitted by the earth. This "energy" is manifest only to a select few.. alas the world's physicists have been unable to measure it and understand its nature.

Geopathic stress levels were determined by a rigorous survey and using sophisticated measurements along all the accident spots on the highway. Apparently the high "geopathic stresses" are indicated by vigorous movement of a dowsing rod like equipment. Geopathic stresses are ranked on a scale known as the Lecher scale from 1 to 15. Spots on this highway go up to 11. 2 on the Lecher.  The greater the movement of the dowsing rod - which a person holds in their hand while surveying- the higher the "geopathic stress". The scale was established after assiduously applying a correction for the "hand tremble syndrome" that seems to afflict practitioners of this art (I made up the last bit).

I am learning a lot!

As a geologist I am not really aware of the earth's magnetic field being distorted by underground sewers and such and that "distortions" will suddenly affect human physiology to the point of being disoriented. Claims that there are cracks in the road due to tectonic movements are also false... "Uhh.. we would have noticed the earthquake?" Movements large enough to generate cracks in the road will have registered on seismometers.. no such largish earthquake damage has been reported by geologists in this part of the country..

After all this hooey.. the Vastuworld team does give admirable advice: major help in reducing the accident rate on the expressway would be that the drivers would still have to drive safely and without breaking the rules.

 Now..the day that happens in India.. the earth will rumble mightily.. right up to 15 on the Lecher scale !

Wednesday, September 4, 2013

Geochemical Data Supports Yamuna Became Tributary Of Ganga In The Pleistocene

How long has the Yamuna been flowing along its present course in the Indian plains i.e. flowing eastwards as a tributary of the Ganga?

Exploring the temporal change in provenance encoded in the late Quaternary deposits of the Ganga Plain - Shailesh Agrawala, Prasanta Sanyal, Srinivasan Balakrishnan, Jitendra K. Dash - Sedimentary Geology April 2013

Temporal analysis of Sr isotopes in soil carbonates and Sr and Nd isotopes in silicate fractions has been carried out in a sedimentary core (Kalpi core; 50 m long) raised from the southern bank of the Yamuna river, Ganga Plain, India. The aim of the study is to constrain sediment provenance through comparison with the modern Himalayan and peninsular river systems' water and bank sediments. Sr isotopic data in soil carbonates (0.71874 to 0.71410) and Sr\Nd isotopic data in silicate (0.72865 to 0.74544 and−13.9 to−17.2, respectively) vary significantly with depth and are indicative of both Himalayan and peninsular sources for sediments in the southern Ganga Plain. The positive correlation between 87Sr/86Sr ratio and 1/Sr in soil carbonate and the negative correlation between 87Sr/86Sr and ╬ÁNd in silicate confirm mixing of sediments from these sources. Variations of 87Sr/86Sr ratios in soil carbonates show that at ~80 and 45 ka the Himalaya acted as the major source of sediments in the southern part of the Ganga Plain. The gradual decrease in 87Sr/86Sr ratios after 80 and 45 ka indicates change in source to peninsular India which is also supported by limited Sr and Nd isotope data in silicates. The change in sediment provenance corresponds well with the available climatic record and is suggestive of strong climatic control in sediment supply with high supply from the Himalaya during the interglacial period and peninsular sediments during glacial period.


Wednesday, August 28, 2013

The Aquifer Underneath My House

... is very prolific.

The photo above taken in March 2012 is of an excavation for a building about half a kilometer away from my home in Pune, India. The developer struck water at around 30 feet below the surface. Water began gushing out of sheet cracks in the basalt rock. Within a couple of days the water level had risen to just a few feet below the surface and then stabilized.

The water level you see in the picture is not the water table but the potentiometric surface. The developer had punctured a confined aquifer. Water in this type of aquifer is under hydrostatic pressure. The puncture or hole is this case creates a pressure gradient and water flowed from the aquifer (high pressure) into the hole (low pressure). It rose until the water pressure at the bottom of the hole equaled the water pressure in the aquifer at which point water stopped flowing out of the aquifer and hence stopped rising in the well /excavation.

In the picture below the red arrows point to the sheet cracks from which groundwater is seeping out.

Wednesday, August 21, 2013

Indian Rationalist Narendra Dabholkar Shot Dead In Pune

Crushingly sad news from Pune, India. Yesterday morning two unidentified gunmen shot dead Dr. Narendra Dabholkar (pictured on left) who for many years had been the public voice of reason, fighting against the superstition and pseudo-science that permeates Indian society. The murder followed a persistent campaign by Dr. Dabholkar to get the Maharashtra state government to pass an anti-superstition bill.

The International Humanist and Ethical Union has a short article  on Dr. Dabholkar and his work.

I often hear people say that differences in belief systems and ideology must be debated peacefully and not result in violent outcomes. I think that really underestimates the power belief systems like religion have over human behavior. Much violence throughout human history has been because people hold what they see as nonnegotiable belief systems which then piggyback and amplify an inherent human tendency to divide people into an "us versus the other". Letting go of such strongly held beliefs becomes a question of self-preservation.

Besides, there is an economic angle to this too. Godmen and clairvoyants in India rake in enormous amounts of money channeled to them by an adoring gullible public. They have dedicated television channels where long distance blessings can be purchased. " Our daughter has been sick for the last 8 months" - "Make sure to  sew buttons of the same color on your husband's shirt.. Your daughter will be cured" is the kind of profound advice I have heard being given and which the believers willingly lap up.

Dr. Dabholkar's work threatened to put the brakes on this lucrative business.

Monday, August 19, 2013

Science Writing In India - 3 Media Coverage Of Climate Change

In the Special Focus section in Current Science, Archita Bhatta gives us a rare glimpse on the evolution of the Indian media coverage on climate change.

There is the predictable push and pull from editors with varying levels of confidence in running stories about global warming. There is the problem of making a case for a phenomenon which is expressed in terms of uncertainties and probabilities. And the Indian media obsession with big occasions like global conferences on climate change with coverage turning a tad jingoistic and self-congratulatory about India's heroic "stand" against the western big emitters.

Nearly missing according to Archita Bhatta is coverage of local stories of changing climate and its consequent impact on ecology and people's livelihoods. This lacunae makes it difficult for the public at large to make the necessary connection between global warming and their own lives.

From the article:

This again takes me back to 2011. Just back from a research on how apple orchards were shifting uphill in Himachal Pradesh because of increase in temperatures, I scanned the papers for the coverage of this in the media. None was found, except for one article in the science and environment magazine called Down to Earth. These local stories of vegetation shifts, reduction in flows in the rivers, loss of crops, drought, etc. might appear as disparate and disconnected, but there lies the failing of the Indian media: it does not grasp the complex connections between these micro-level changes with the larger global changes.

The result is that climate change reportage is viewed by the public as a ‘mere policy issue for 'intellectuals’, remote and unconnected to their lives. 

This has to change

So the situation remains the same as when I travelled across central India to report on how extreme rainfall and drought there had affected people’s lives. Farmers affected by unexpected rainfall in groundnut-growing areas of Andhra Pradesh, did not understand ‘climate change’ as the professor spoke of.

This has to change

The rapidly decreasing rainfall in Chhattisgarh did not make sense to the farmers there; connecting this to the fast burgeoning vehicular population, or the consumptive lifestyle of their middle-class urbane brethren. It is most likely they still do not understand, because we in the media have ourselves not seen the real connection and are comfortable chasing policy diatribes and quoting big politicians.

This is what has to change ..towards building a strong bench of climate change journalists who understand the complex subject and connect it to the lives of the common people, the community that will finally make the difference in climate change scenario happen.

Do read.

Tuesday, August 13, 2013

Is It Possible To Predict The Past

.. is the name of an article published in Lithosphere (open access) by Chris Paola of the University of Minnesota. It begins like this:

On p. 343–354 of this issue Engelder and Pelletier (2013) argue that relatively long-term autogenic variation in the degree of channelization of gravel-transporting fluvial systems can result in cycles of aggradation and incision that can reduce the slopes needed for gravel transport and hence allow for unexpectedly long distances of gravel runout.

In case your eyes have already glazed over I request a little patience and suggest you read the entire article, for at the heart of it is a thoughtful defense of uniformitarianism , one of most fundamental concepts in geology.

Thursday, August 8, 2013

Science Writing In India - 2 Writing In Hindi

In the Special Focus section on Science writing in India in Current Science Sopan Joshi writes about the difficulties of writing about science in Hindi:

The world of science has developed a great bias towards English. The research comes from the English-speaking world,so the idiom is culturally English. The Hindi readership is not familiar with this idiom. For example, imagine the words required to explain plate tectonics in Hindi. For most scientific terms, there are translations in Hindi. But those translations mean nothing to the average reader. In fact, they mean very little to even the students of science. Because they are never used outside the classroom.

Each writer has to negotiate this problem on his terms, given his limitations. In my experience, using the metaphor of labour is useful. So, in a Hindi article on the world of computers, I have used the metaphor of carpentry to explain the nuance of a graphical user interface. To talk about the relationship between an operating system and computing software, I have found myself using the image of railway tracks and trains running on them. To talk about climate change and its impact on the monsoon, I have drawn from Hindu customs and mythology.

While this makes the material more accessible to a wider readership, it also dumbs down the narrative. One gets the feeling that there is no room for the beauty of complexity. Since there is very little written on science in the Hindi media, one also regrets the absence of a peer group. When you are  struggling with a choice of words, because you cannot think of words and phrases that can convey the meaning accurately and interestingly, you need peers to bounce off ideas, get feedback.

Since almost all post-high school science education in India is in English these problems do apply to other Indian languages as well.  Sopan Joshi should take heart that the Science Bloggers Association of India has put together a Hindi language science writing ecosystem which could provide him a sounding board for his ideas.

The world of science has recently developed a bias towards English, but don't forget there is a vast research literature in Russian, French, German, Chinese and Japanese, countries that unlike India have been using native languages for post high school science education.

Tuesday, August 6, 2013

Some Interesting Papers On Himalayan Sedimentary Record By Indian Academics

A long time ago I mused that my perception was that in the context of Indian geology research, papers in top international sedimentary journals featured more Bengali geologists based in Universities in Bengal and eastern parts of India than from any other ethnic or linguistic region in India. That was fun lazy speculation on my part but perhaps not entirely wrong.

So, it is very refreshing to see a flurry of papers in recent issues of Sedimentary Geology from non Bengali research groups from other parts of the country as well!

1) Early Oligocene paleosols of the Dagshai Formation, India: A record of the oldest tropical weathering in the Himalayan foreland - Pankaj Srivastava, Subhra Patel, Nandita Singh, Toshienla Jamir, Nandan Kumar, Manini Aruche, Ramesh C. Patel

As the Indian collision with Asia progressed, the sea of Tethys shrank. Marine environments gave way to terrestrial basins. This work uses ancient soils that formed on these early terrestrial sediments during breaks in sedimentation to infer paleoclimate. The conclusion is that the climate was tropical with monsoonal conditions.

2)  Late Miocene–Early Pliocene reactivation of the Main Boundary Thrust: Evidence from the seismites in southeastern Kumaun Himalaya, India - Anurag Mishra, Deepak C. Srivastava, Jyoti Shah

The Himalayan terrain is broken up by several major thrust faults. Out of these, the Main Boundary Thrust brings into contact the Proterozoic Lesser Himalayas over the Cenozoic foreland basin sediments. The nature and reactivation history of the Main Boundary Thrust is not completely understood. A study of soft sediment deformation in foreland basin sediments in the vicinity of the Main Boundary Thrust documents sedimentation contemporaneous with seismic events.  Magnetostratigraphy indicate a Late Miocene-Early Pliocene reactivation of this major thrust fault.

3)  Exploring the temporal change in provenance encoded in the late Quaternary deposits of the Ganga Plain - Shailesh Agrawala, Prasanta Sanyal, Srinivasan Balakrishnan, Jitendra K. Dash

The rivers in the Ganges plains receive a lot of sediments from the Himalayas. But that is not their only source of sediment. Rivers like the Chambal, draining the Indian craton composed mainly of Precambrian granites and meta-sedimentary and meta-igneous rocks and the Late Cretaceous -Earliest Cenozoic Deccan Basalts contributes prodigious amounts of sediment especially to the Yamuna. A geochemical analysis of cored sediments from the Yamuna finds important contribution through the Pleistocene from both Himalayan and cratonic sources. Interestingly, there is a climatic control on the relative proportions of sediments received from the two sources. Himalayan sediments dominate during interglacial phases while cratonic sediments dominate during glacial phases. Expansion of mountain glaciers during cold intervals would have reduced supply of sediments from the Himalayas.

Thursday, July 25, 2013

Science Writing In India And Some Thoughts On Punctuated Equilibrium

Kind of a hodge podge title but I didn't feel like writing two separate posts.

Current Science had a special focus a couple of weeks ago on science writing in India. Seema Singh has written quite well about her struggles to become a better science writer. She summarizes the state of science writing in India:

Science is just about reviving in India. People mention that the first time in three decades such a coordinated effort is being mounted to infuse funds and sparkle in Indian science. But there still are not too many stories that can be told with a single-sentence punch line. In which case, the art of chronicling the process becomes even more important. Now, whether the body of knowledge will help here, or the skill of storytelling, is left to my mind, to individual communicators, specialists or non-specialists. For me, personally, it is about homework and humility, intricate osmosis of critical inquiry and sensitivity, the spirit of curiosity, sense of wonder, and, of course, fact checking.

That's an important point about what and how science gets covered. Far too often, the media either exults in and tries to claim an Indian connection to a notable piece of research by an Indian scientist who left the country 20 years ago, or features scientists based in India only during satellite launches, nuclear power plant protests or major earthquakes. Science as an activity and scientists in their day to day working avatar are rarely featured.  A trigger to change this could come from within too. Few Indian scientists today are using social media platforms to initiate a conversation with the public. There has been a small increase in the number of Indian scientists who do blog with biologists and ecologists (1, 2) taking the lead, but my impression is that far too many write about everything else but their research.

Seema Singh also writes about her interesting encounter back in 2001 with evolutionary paleontologist Stephen Jay Gould who popularized the field of evolution like no other writer except perhaps Richard Dawkins. Gould along with Niles Eldredge proposed the controversial and widely misunderstood theory of punctuated equilibrium. Seema Singh describes it thus: ... which propounded that evolution takes place in rapid spurts of species differentiation, not in continuous transformations.

I wanted to expand on this.

Tuesday, July 23, 2013

Field Photo: A Village In The Monsoons

Can monsoon magic get better than this?

A small village, flooded paddy fields, cool breeze, clouds and the majestic Deccan volcanics towering over..

Taken on way to Panchgani from Pasarani Ghat.

Thursday, July 18, 2013

Periods Of Non Deposition of Sediments Are Transformative And Useful Recorders Of History Too

Came across this interesting article published a few months ago in Sedimentology:

Deciphering condensed sequences: A case study from the Oxfordian (Upper Jurassic) Dhosa Oolite member of the Kachchh Basin, western India -Mathhias Alberti, Franz Fursichi, Dhirendra Pandey

Properties of sediments and sedimentary rocks tell us a lot about the geological history of the depositional basin as well as for clastic sedimentary rocks the history of the source terrains from which the sediment was weathered, eroded and transported. But why study phases of basin evolution when no sediment or very little sediment is deposited. What imprint do such events leave on sedimentary basins? What can such episodes tell us about sea level change, tectonic movements and climates? The authors address this issue by examining one of the most prominent marker beds from the Jurassic rift basins of western India, the Dhosa Oolite.

In large parts of the Kachchh Basin, a Mesozoic rift basin situated in western India, the Oxfordian succession is characterized by strong condensation and several depositional gaps. The top layer of the Early to Middle Oxfordian Dhosa Oolite member, for which the term ‘Dhosa Conglomerate Bed’ is proposed, is an excellent marker horizon. Despite being mostly less than 1 m thick, this unit can be followed for more than 100 km throughout the Kachchh Mainland. A detailed sedimentological analysis has led to a complex model for its formation. Signs of subaerial weathering, including palaeokarst features, suggest at least two phases of emersion of the area. Metre-sized concretionary slabs floating in a fine-grained matrix, together with signs of synsedimentary tectonics, point to a highly active fault system causing recurrent earthquakes in the basin. The model takes into account information from outcrops outside the Kachchh Mainland and thereby considerably refines the current understanding of the basin history during the Late Jurassic. Large fault systems and possibly the so-called Median High uplift separated the basin into several sub-basins. The main reason for condensation in the Oxfordian succession is an inversion that affected large parts of the basin by cutting them off from the sediment supply. The Dhosa Conglomerate Bed is an excellent example, demonstrating the potential of condensed units in reconstructing depositional environments and events that took place during phases of non-deposition. Although condensed sequences occur frequently throughout the sedimentary record, they are particularly common around the Callovian to Oxfordian transition. A series of models has been proposed to explain these almost worldwide occurrences, ranging from eustatic sea-level highstands to glacial phases connected with regressions. The succession of the Kachchh Basin shows almost stable conditions across this boundary with only a slight fall in relative sea-level, reaching its minimum not before the late Early Oxfordian.

So even a thin layer of sediment (compared to the time it represents) can be an important recorder of history.

Here, the Dhosa oolite, a complex bed of detrital particles, diagenetic coated grains and intraclasts cemented together to form a distinctive horizon represents very slow accumulation of material in a basin.

My interest is in the even more extreme situation when absolutely no sediment accumulates in a basin. In fact, my entire PhD research was on such events of non-deposition and what effect they have on earlier deposited sedimentary sequences.

Monday, July 15, 2013

My New Book Shelf

..has gone digital!

First downloads:

The Universe Within: Neil Shubin
Written In Stone: The Fossil Record And Our Place In Nature: Brian Switek

I realize that I am reading at a faster pace on my Kindle than my usual pace with print. Maybe the bad habits of skimming through internet material is translating to book reading too. I need to adjust that. Otherwise I am enjoying the experience. My strategy for now is to buy special interest, semi technical books in the Kindle format while sticking to print books that I would like to share with friends. 

Wednesday, July 3, 2013

Mountains Of Saint Francis - Walter Alvarez

A certain type of travel book or TV show on Italy features the adventurer driving through sun dappled rolling hills and winding narrow roads to a picturesque village in search of that one undiscovered Trattoria not featured in similar other books or TV shows. Walter Alvarez though refreshingly keeps driving past these rustic eating places to an old quarry just beyond the village. There, he begins poking around in the rocks in an attempt to unravel their secrets.

Walter Alvarez is quite a famous geologist. He was one of the proponents of the theory that a meteorite impact precipitated a mass extinction 65 million years ago, an idea that is now amply supported by evidence.  He has written a story about that discovery in T Rex And The Crater Of Doom (dinosaurs were the most famous casualty of this event). He has had a long professional relationship with Italian geologists and he uses the Italian rock record to explain the methods and basic principals used by geologists in this enjoyable book The Mountains Of Saint Francis: Discovering The Geologic Events That Shaped Our Earth. 

The Mountains of Saint Francis (after Francis of Assisi) is Alvarez's name for the Apennine mountains of the Tuscany and Umbria region and this books explains step by step how they came to be. Throughout the Mesozoic until mid Cenozoic, what is now Italy, was a promontory of the African continent sticking out like a north pointing thumb into the sea of Tethys that separated Africa and Europe. An enormous pile of mostly limestone accumulated on this submerged promontory. These Jurassic to mid Cenozoic limestones form the building block of the Apennine mountains. They stand spectacularly exposed in road cuts and cliffs and have attracted the attention of geologists from all over the world.  As a result, the Apennine rock exposures along with younger Pleistocene deposits have become some of the best studied strata in the world. They not only tell us about local geological evolution, but have provided key insights to answer some broad geological questions.

Wednesday, June 26, 2013

Google Reader Is Shutting Down on July 1 2013

Just a reminder that Google Reader will be shutting down come July 1 2013. If you have been reading this blog via my RSS Feed in Google Reader do change over to an alternative. Feedly seems to be a popular choice, with a feature to import your aggregated Google Reader feed at a click. although there are many others too. Here are two articles that explore replacements for Google Reader.

Moving On From Google Reader

There Is No Google Reader Replacement, Only Alternatives

Again, here is my RSS Feed and as always, thanks for your support.

Monday, June 24, 2013

Dog Domestication Controversy: When, Where And How Many Times?

Interesting article in Nature on advances in our understanding about dog domestication. Apparently it is a "sexy field" of study:

"In recent months, three international teams have published papers comparing the genomes of dogs and wolves. On some matters — such as the types of genetic changes that make the two differ — the researchers are more or less in agreement. Yet the teams have all arrived at wildly different conclusions about the timing, location and basis for the reinvention of ferocious wolves as placid pooches. “It’s a sexy field,” says Greger Larson, an archaeogeneticist at the University of Durham, UK. He has won a £950,000 (US$1.5-million) grant to study dog domestication starting in October. “You’ve got a lot of big personalities, a lot of money, and people who want to get their Nature paper first.”

Fossils and genetic data are in conflict too. Fossil skulls with dog like features dating back to around 33,000 years have been reported from Siberia and Belgium. There is genetic work that suggests that China was where the first dogs were domesticated at a similar early date of around 32,000 years ago. Other scientists feel that these early lineages went extinct without contributing to extant dogs which according to them evolved post ice age maxima beginning around 15,000 years ago or so. Yet others think that dog domestication coincided with the advent of agriculture about 10,000 years ago.

I think multiple episodes of domestication at various times is an entirely reasonable possibility given that both wolves and humans are hyper social and the opportunities to clash, cooperate and be fascinated with each other would have arisen again and again.

Expect more trading of intellectual blows as genomics will bring a tighter focus on the timing and geography of dog origins.

"The move to look at ancient DNA could make the small field of dog genetics even pricklier, because archaeological bone samples are so precious. Novembre says that he finds the field more fractious than human genetics, and says that his experience has given him pause about future canine work. “It’s really intense in the dog world,” he says. But Boyko, who also collaborates with the Chinese group, says that although the field is competitive, it remains collegial. “At the end of the day, we sit back and enjoy a beer together when we see each other.”

Thursday, June 20, 2013

Creationists Don't Get The Cambrian Explosion

There is an excellent post by Nick Matzke on the Panda's Thumb on the Cambrian Explosion, which was the evolutionary radiation and diversification of animal life over a 30 million year period from about 540 mya to 510 mya. To clarify, the lower boundary set at around 540 mya does not mean there is no evidence of animal life before that and "poof" animals originated instantaneously at 540 mya. On the contrary, there is long earlier history of multicellular animal life preserved in various forms including the famous Ediacaran biota going back another 10's of million years or so,  but the fossil record does become more prolific beginning about 540 mya. The important point is that complex forms evolved and diversification occurred in recognizable stages, not all at once. So yes, there are "transitional fossils" preserved from this time period!  There are geological and ecological reasons for why animal life diversified and was preserved better by 540 mya, but that is another story.

Nick Matzke has written this post as a rebuttal to a book by Stephen Meyer titled Darwin’s Doubt: The Explosive Origin of Animal Life and the Case for Intelligent Design.

It is a long post but well worth reading. You will learn:

1) What is the nature of the fossil record beginning late Proterozoic and the Cambrian.

2) What methods of analysis are being used by paleontologists to make sense of this fossil record and what is the current thinking on how these ancient animal groups of the Cambrian were related to each other and to extant animal groups, with implications for how and when diversification from simpler forms took place.

3) How Creationists obfuscate, ignore and are ignorant of both, the nature of the fossil record and analytical methods, resulting in them misdirecting readers about the actual state of our knowledge.

Do read it.

Thursday, June 13, 2013

Benjamin Franklin And Erasmus Darwin: Musings About Geology and Evolution

I am reading When You Were A Tadpole and I Was A Fish  by Martin Gardner. It is a collection of essays on science and culture. There is a really good one on the complex personality of Isaac Newton, another one on Ann Coulter's rants against evolution and quite a bit of writing on debunking paranormal claims. I haven't yet finished the entire book with some chapters on literature and religion still unread. I am not sure they will hold my interest as there is more critical dissection of literary figures like Chesterton and a long explanation on why he (Mr. Gardner) is not an atheist than I care to read about.

In one of the chapters Mr. Gardner gives a list of anticipations made by famous figures about how the world works which have turned out to be right, although not in all details. The larger point he is making throughout the book is the lack of evidence for clairvoyance. People are making predictions all the time. Most of them turn out to be wrong. We however tend to remember and wonder only at the tiny fraction that turn out to be correct.

He off course does not categorize Benjamin Franklin and Erasmus Darwin as people making loose predictions. They were both far better thinkers than your run of the mill soothsayers and fortune tellers. Their musings were serious attempts to understand natural processes and were not just opportunistic attention grabbing stunts.

This is Benjamin Franklin in a letter to Abbe Soulaive, September 22, 1782:

"Such changes in the superficial parts of the globe seemed to be unlikely to happen if the Earth was solid to the centre. I therefore imagined that the internal parts might be a fluid more dense, and of greater specific gravity than any of the solids we are acquainted with; which therefore swim in or upon that fluid. Thus the surface of the globe would be a shell, capable of being broken and disordered by the violent movements of the fluid on which it rested."

Tuesday, June 11, 2013

Exhumation Patterns Of Dhauladhar Range Himalayas: Interplay Of Tectonics And Climate

Open access in Current Science:

 New apatite and zircon fission-track ages from the Dalhousie Granite exposed along Dhauladhar Range, Northwest Himalaya extend from 2.9 ±  0.2 to 4.4± 1.0 Ma and 10.4 ±  1.4 to 21.1 ±  2.2 Ma respectively. One-dimensional thermal modelling of the data suggests slow exhumation during Middle to Late Miocene, followed by acceleration during Plio-Pleistocene. The activity along the Panjal Thrust (PT)/Main Central Thrust (MCT) in this region ceased at ~ 15 Ma, while tectonic activity along the Main Boundary Thrust (MBT) started prior to ~ 10 Ma. Tilting of topography due to activation of MBT controls the exhumation pattern of Dalhousie Granite during Middle to Late Miocene. Correlation among structure, topographic pattern and thermochronometric ages indicates interplay between tectonics and erosion controlled  exhumation along the mountain front. The fast exhumation rates since Pliocene are synchronous with intensification of the Asian monsoon and suggest a causal link between erosion and climate variation for evolution of the landscape.

What is heartening to see is that research like this requiring sophisticated geochemical analysis is coming out of regional Universities like Kurukshetra and Ambala.  Ten to fifteen years ago, a paper like this would be most likely published from labs of just a few elite institutions in India, with the analysis being done by a Western collaborator in a U.S. or European University. That is still the case with many research programs, where Indian geologists seek collaboration to access instrumentation not easily available in India, but with more money being available through Science and Technology Ministry grants, the research environment may be slowly changing.

A while ago I had an email exchange with a senior geology faculty where I ventured to ask him if my perception was correct that many really large research projects on Himalayan tectonics involve primarily Western researchers with a solitary India based colleague. He agreed somewhat, but opined that this was not because there is a lack of research funding potentially available to address Himalayan geology, but rather funding towards subjects like climate change, groundwater, Quaternary processes and environmental geology has increased and many researchers today prefer more theoretical and lab based work than difficult high altitude Himalayan fieldwork!

A bit unkind I thought :).. but this paper is a departure from such slack attitudes if they really do exist!

Monday, June 3, 2013

Going Hiking In Pangaean India

I have been thinking unhappy thoughts ever since I came upon this map of Pangaea with today's political boundaries overlaid on it.

Where would I have going hiking in Pangaean India?

1) The Himalayas, crown jewel of hikers arose begining early Cenozoic and reached their bewitching heights in the mid Miocene -Pliocene.

2) The Western Ghats, the poor man's Himalayas, arose in the Cenozoic too after the breakup of India from Madagascar (88 mya) and Seychelles (66 mya). They represent heights reached due to an initial high rift flank, amplified by denudational isostacy and crustal upwarp due to intraplate stresses propagated southwards from the Himalayan collisional zone.

3) The Eastern Ghats, a line of mountains parallel to the east coast of India also arose much later than Pangaea forming during and after the breakup of India with Antarctica about 130 mya.

4) The Vindhyan and Satpura mountains in central India are composed of Proterozoic and late Paleozoic -Mesozoic rocks resp. but much of today's relief also represents topography rejuvenated since mid Cenozoic, ultimately related to stresses from the Himalayan collision.

5) The Aravalli mountains in Rajasthan is a Proterozoic orogenic belt but probably didn't have much topography during Pangaean times.

For most of the time period from Cambrian to Carboniferous the Indian shield was a tectonically stable area. Pangaean India was a place where a vast peneplain had developed over most of the Indian shield in response to long lasting denudation. This cycle of deep weathering and erosion lasting tens to a hundred million years would have stripped and ultimately flattened the Aravalli and south Indian orogenic mountains, exposing mountain roots and lower crustal rocks like granulites and charnokites. The result would have been a subdued topography with a flat horizon as far as the eye can see, occasionally interrupted by gentle rolling hillocks made up of more resistant lithologies like quartzites and charnokites. 

Subsequent episodes of uplift and erosion has destroyed this flat topographic surface from all over the Indian peninsular region but some remnants of this peneplain termed the Gondwana surface can be observed at around 2400 m mantling the granulites of south India around the popular hill stations of Ooty and Kodaikanal in the Nilgiri mountains.  It has been lifted to these heights during Cenozoic uplift of the Western Ghats.

The only places of considerable relief would have been the emerging Permo-Triassic rift basins of the Satpura, Pranhita Godavari and Mahanadi belts in the central and eastern part of  country. A horst graben structure would have resulting in a ridge and flat valley type topography. Not particularly attractive for a challenging hike. Plus it was really swampy and hot in those rift basins.

I wouldn't have liked to live in Pangaean India. I am too spoilt by views like this one, which appeared only in the Miocene.

Photo: Nanda Devi and Namik Glacier in the Kumaon Himalayas, November 2012.

Saturday, June 1, 2013

An Ecologist's Passionate Plea To Protect The Western Ghats

In March 2010 the Ministry of Environment and Forest, India,  constituted the Western Ghat Ecology Expert Panel to study and recommend protection for the ecologically sensitive Western Ghat region. The panel was headed by Dr. Madhav Gadgil. It came up with the idea of a  graded approach to protection, essentially sequestering some areas from any mining and other development,  limited development in other areas and so on. Central to their philosophy of protection was that the voice of the local people be heard. All decisions regarding development would be taken only after extensive consultations with the people of the villages being affected by various developmental projects.

The Indian government, both Central and various State bodies did not like this plan. They undertook what is becoming a depressingly familiar route. They constituted another committee termed "High Level Working Group" to relook the original recommendations. Predictably, the new report by this high level group guarantees protection for a much smaller region of the Western Ghats and does not see a role for village level committees to participate in decisions regards protection and development.

Dr. Madhav Gadgil has come out strongly against this new report headed by Dr. K. Kasturirangan and has written an open letter to him in The Hindu:

An excerpt-

India’s cultural landscape harbours many valuable elements of biodiversity. Fully 75 per cent of the population of lion-tailed macaque, a monkey species confined to the Western Ghats, thrives in the cultural landscape of tea gardens. I live in the city of Pune and scattered in my locality are a large number of banyan, peepal and gular trees; trees that belong to genus Ficus, celebrated in modern ecology as a keystone resource that sustains a wide variety of other species. Through the night I hear peacocks calling, and when I get up and go to the terrace I see them dancing.

It is our people, rooted in India’s strong cultural traditions of respect for nature, who have venerated and protected the sacred groves, the Ficus trees, the monkeys and the peafowl.

Apparently, all this is to be snuffed out. It reminds me of Francis Buchanan, an avowed agent of British imperialism, who wrote in 1801 that India’s sacred groves were merely a contrivance to prevent the East India Company from claiming its rightful property.

It would appear that we are now more British than the British and are asserting that a nature-friendly approach in the cultural landscape is merely a contrivance to prevent the rich and powerful of the country and of the globalised world from taking over all lands and waters to exploit and pollute as they wish while pursuing lawless, jobless economic growth. It is astonishing that your report strongly endorses such an approach. Reality is indeed stranger than we can suppose!

And here is another article by Dr. Gadgil and Ligia Noronha on the subversion of the Gadgil report. 

Sunday, May 26, 2013

Monday, May 20, 2013

Its In The Syllabus

From PhD comics:

The tables can very easily be turned on you, the faculty, when a student goes over the syllabus with a tooth comb and then holds you to every dot and comma in it.

My friend who is an igneous petrologist and faculty at a local university here in Pune saw the nasty side of the syllabus centered education. As a researcher, my friend is highly enthusiastic about his work and often launches into long excursions about it during lecture time. He didn't think the students minded until he posed a question about his research in an exam. There, some students objected... it was not in the syllabus you see!  They took their complaint to the Vice Chancellor of the University and had the exam annulled.

This happened at a post-graduate level i.e. these were students studying for their Masters degree, a level at which students should be learning not just the fundamentals of a subject but also exploring the boundaries of knowledge about a topic by diving into the research literature and hungrily biting at anything extra that comes their way. It makes you wonder about the motivation and mindset of these students that they so quickly and vehemently protested against a faculty who actually wanted to go out of his way and teach more than is required of him.

I hate to think that the narrow minded focus on rigid syllabus and passing exams has reached such a level that it is destroying any curiosity to learn more.

Thursday, May 16, 2013

Again! Charles Darwin Was Wrong.. About The Tree Of Life

Well.. I guess the headline "Darwin Was Wrong" always sells!

But The Guardian should have thought a little before publishing this. It is an article which appeared sometime back but is the most viewed in the science section and is about how the recognition of lateral gene transfer i.e. the transfer of genes aross taxonomic groups is proving Darwin's idea of a tree of life wrong.

Read this passage:

Evolutionary biologists say crossbreeding between species is far more common than previously thought, making a nonsense of the idea of discrete evolutionary branches.

I don't think their science correspondence Ian Sample thought enough to see the contradiction in this passage.

Cross breeding between species implies that species exist in the first place which in turn means that there has been in existence discrete evolutionary branches i.e. long periods of independent evolution of different populations so as to have accumulated unique features recognizably different from other populations. Its only when there are discrete unique branches is it possible to recognize lateral gene transfer between the two!

For example, coyotes and wolves are closely related animals that occasionally interbreed in the wild. But the fact that we can recognize coyotes from wolves means that these are two discrete lineages having diverged from a common ancestor at some point in the past and have since followed separate evolutionary trajectories accumulating unique traits along the way. Occasional interbreeding between the two does not wipe away all these differences. They remain two distinct branches on the canid family tree.

Gene trees are not the same as species trees. Gene trees reflect the evolutionary history of a gene which may be transferred across taxonomic groups by a variety of processes. Early in the divergent history of populations genes may be exchanged through interbreeding. Or, for example a not so insignificant portion of the genome of mammals is made up of fragments of genes from other species transferred into us long ago by viral infections. However, that does not change the historical fact that the coyote and the wolf, or for that  matter humans and chimps diverged from a common ancestor. Species trees or the tree of life reflects this history of speciation. So, Darwin's tree of life idea is about diverging populations from a common ancestor. These populations despite occasional transfer of genes maintain reproductive integrity and become different enough over time. Life has become diverse over time by such branching. Darwin was not wrong about that.

And what does one make of this confused para- Last year, scientists at the University of Texas at Arlington found a strange chunk of DNA in the genetic make-up of eight animals, including the mouse, rat and the African clawed frog. The same chunk is missing from chickens, elephants and humans, suggesting it must have become wedged into the genomes of some animals by crossbreeding.

Does that mean there was interbreeding between mouse, rats and the African clawed frog? Ridiculous!

Update May 16 2013: There is another potentially misleading passage in the article:

But modern genetics has revealed that representing evolutionary history as a tree is misleading, with scientists saying a more realistic way to represent the origins and inter-relatedness of species would be an impenetrable thicket. Darwin himself also wrote about evolution and ecosystems as a "tangled bank".

Now, the "tangled bank" has nothing to do with lateral gene transfer and interbreeding at all. It should not be conflated with evolutionary relationships being described as a web or a thicket. Darwin was describing the complex inter-dependencies in an ecosystem as organisms compete and co-operate with each other for resources.

Tuesday, May 14, 2013

Genghis Khan And Interdisciplinary Research

State of the Planet has quite a readable account of how a period of warm climate in the early 1200's may have produced an abundance of grass and livestock in Mongolia, fueling the expansionist ambitions of Genghis Khan.

Here is an interesting passage from the article:

In 2013, Avery Shinneman, a biologist at the University of Washington, will analyze sediments at selected lakes in order to estimate abundances of livestock over time, using varying levels of fungal spores that live in the dung of grazing animals, and algae fertilized by that dung. The data will be fed into a model developed by Hanqin Tian, an ecologist at Auburn University in Alabama, who studies the weather of modern Mongolia and its relation to grassland productivity. The Mongols left few written records, but Nicola di Cosmo, a historian at the Institute for Advanced Study in Princeton, N.J., will look into contemporary accounts from China, Persia and Europe for clues to climate and military events. From all this, the researchers hope to develop a picture of how sun, water, soil and animals might have created an energy system that the Mongols could have tapped into.

Biologists, theoretical ecologists, historians... increasingly big projects like this one become interdisciplinary by necessity.

If you have been following my posts on the controversy over a paper by Giosan et al on the geomorphology of rivers feeding the Harappan that was a big project involving geomorphologists, climate experts, paleobotanists, sedimentologists and geochemists. The paper had 15 authors. You could have confused the author citations for the abstract! :)