An Outing With William Smith

I have started reading Roger Osbourne's The Floating Egg: Episodes in the Making of Geology.

It tells stories set mostly in the 1800's from the Yorkshire region of England of people involved in exploring landscapes, discovering fossils, and slowly constructing a systematic science of geology. The story of James Hutton's insight that the earth was really old based on his observation of the juxtaposition of two sets of strata at Siccar Point on the east coast of Scotland is well known. From that he deduced that the lower set of strata were deposited first, then tilted and eroded, upon which the upper set of strata were deposited. This meant that a vast amount of time separated these events.

In the late 1790's England, the need to transport coal from mines to industry led to a surge in canal building, as transport by barges was cheaper. William Smith was one surveyor in much demand. He began observing consistent patterns of rock and fossil associations through his explorations and realized that he could use these patterns to predict the presence or absence of certain rock types or fossils deep underground, even if the complete association of rocks was not exposed at the surface. Smith went on to make the first detailed geologic map of Britain, a tale best read in Simon Winchester's The Map That Changed The World.

Roger Osbourne imagines a conversation William Smith has with a fellow traveler, a Mr. Palmer of Somerset Canal Company, while on survey near the city of York. Mr Palmer is the narrator.

They climb a high tower which affords a view of the surrounding countryside. William Smith's eyes light up when he sees a line of hills in a distance.

'You are a coal mining man, Mr. Palmer, and for that you have my respect. Now if you were to go to those chalk hills and dig for coal, you would never find it. Never'

Though I had believed I understood Smith's explanations,this seemed a truly fantastic inference.

'But how can you know that Mr. Smith?  Those hills are more that twenty miles away'

'Think on it Mr. Palmer, think on it. You would need to dig through chalk,which is perhaps 500 feet thick, then through shale, limestones and red sand before you even got to the coal measures. You would be miles under the earth'.  He laughed at the thought of it.

'Can this be true?' I asked.

He turned to me, his face and eyes set strangely with a conviction that I had never seen on any man.

'Not "Can it be true?" Mr Palmer. It must be true. These are the laws of nature. They have no variance. What I seek is a philosophy which will embrace the whole earth. It cannot allow any exception'. 

The year is 1794. William Smith was optimizing mineral exploration strategy based on his new found understanding that the package of coal overlain by red sand, overlain by limestone then shale and then chalk will occur unvarying in this region.

A thousand such observations followed by countless inferences ultimately coalesced in to a rigorous science of geological mapping.

This is a lovely book.

Review Papers: Geodynamical Evolution Of India

Episodes, Journal of International Geoscience, has an open access special issue on the geology of the Indian subcontinent.

Excellent source for teachers, researchers, and curious science lovers.

I liked the paper on Deccan Volcanism a lot, especially the emphasis and attention given to the physical properties of the lava flows, and the problems of correlating (establishing their genetic and temporal relationships) lava sections from different parts of the Deccan Volcanic Province.

I don't know much about the Archean to Neoproterozoic age ( > 2500- 542 million years old)  southern granulite terrain, a region where very high temperature high pressure rocks known as granulites and charnockites are exposed. That is a topic I am looking forward to reading and learning about. The famous Anamudi Peak in the Western Ghats  are made up of these rocks. Geologists suspect that their high altitude is partly a result of differential erosion. Charnockites in particular are harder and have resisted being worn down, resulting in them standing out as high domes.

Another cool paper is on the role of microbial colonies on sedimentation patterns in the Proterozoic sedimentary basins of India (2500-542 million years ago). Microbial colonies grew as mats covering sediment surfaces influencing their accumulation and erosional patterns. Such environments became rare since Cambrian times (542 million years ago) when animals which eat and disrupt microbial colonies evolved.

Dive in.

Palghar Earthquake Swarm

My article on Palghar's mystery earthquakes has been published in The Wire Science. The article is an explanation of a recent paper that was published in the journal Tectonophysics. It favors the view that groundwater circulation is causing slippage along faults. According to the scientists involved the earthquakes are due to these very local processes.

One important point is that a link between groundwater and these tremors, even if it does exist here, represents a tipping point in a longer buildup of stress due to tectonic forces. The western margin of India is riddled by large fracture zones and faults. These structures haven't formed by groundwater movement. They are a legacy of earlier and ongoing crustal deformation due to regional and continent wide geological forces.  Groundwater flow or a build up of pore pressure cannot by itself generate enough stress to develop a fault de novo.

Dhundhalwadi is experiencing what is known as an earthquake swarm, a sequence of seismic activity with no clear peak (mainshock), and which is localised to one area. A recent study by researchers around India, including the National Institute of Seismology, has found one potential explanation for the swarm that draws a link between the monsoons, groundwater circulation and rock deformation...

Read more here.

Articles: Dehradun, Early Dogs, Warm Blooded Dinos, Louisiana Delta

Sharing some links from the past few days:

1) Dehradun.

A story of the transformation of a beautiful hill town to an ugly unplanned urban center. We shrug resignedly at many such tales from across the country. This one is of Dehradun. Himalaya towns can only be described as disasters in the making. Unscientifically built infrastructure on steep slopes, no garbage management resulting in enormous stray dog and pig populations roaming the streets, and a dwindling water supply. Yet these towns continue to grow, pointing to worsening opportunities for making a livelihood in the Himalayan rural landscapes. The 'smart city' reference is the ultimate insult of all.

Vanishing landscape of ‘smart city’ Dehradun.

2) Early Dogs.

The early stages of dog domestication may have seen a marked behavioral shift appearing before any distinct morphological change. This change in behavior, arising from docile wolves or 'protodogs' living near human camps would have entailed a change in diets.  Scientists have compared wolf and dog like remains from a 28,500 year old site in the Czech Republic. They looked at the dental microwear pattern of these two groups of canids and noticed that the dog like canids show a pattern consistent with eating more hard brittle foods. The wolves show patterns consistent with eating more flesh. 'Throw this dog a bone" wasn't an insult then.

Dental microwear as a behavioral proxy for distinguishing between canids at the Upper Paleolithic (Gravettian) site of Předmostí, Czech Republic

write up: Dog domestication during ice age.

3) Warm Blooded Dinos?

Were Dinosaurs warm blooded like mammals? This debate has raged on for decades. Bone growth patterns have not given any unambiguous evidence of body temperature regulation. A new method known as clumped isotopes may provided a more reliable indicator of estimating body temperatures. Fossilized dinosaur egg shells contain the original calcium carbonate from which these shells were built. A variety of carbon isotopes (C12, C13) may bond with a variety of oxygen isotopes (O16, O17, O18) in the carbonate molecules (CO3). The degree of bonding or clumping of the heavier isotopes i.e. C13 to O18 varies with the temperature during mineral growth. Clumping is more at lower temperatures.

Scientists compared this C13-O18 clumpiness in dinosaur egg shells with C13-O18 clumpiness in the calcium carbonate of mollusc shells from the same fossil bed. Mollusc geochemistry is taken to be a proxy for the ambient conditions. They found out that the egg shells grew at temperatures between 25- 43 deg C, while the molluscs record growth at 25 -30 deg C. This suggests that dinosaurs were capable of maintaining a higher body temperatures than their surroundings.  As a carbonate sedimentologist, I found the details of methods in this paper  of great interest. The researchers used a variety of techniques to make sure that the egg shells had not been altered or subjected to higher temperatures later in their history, which would have made them an unreliable archive of the original temperature during growth. The analyzed egg shells came from Sauropods, Theropods and Ornithischians, a sample across the three main groups of dinosaurs. Very interesting study.

Eggshell geochemistry reveals ancestral metabolic thermoregulation in Dinosauria

write up - Fossil Eggshells Suggest All Dinosaurs May Have Been Warm-Blooded

4)  Eroding Louisiana Coastline.

Over the past several decades, barrages and levees have drastically reduced the amount of sediment that the Mississippi river is carrying to the sea. As a result, the famed Mississippi delta and coastline is eroding away. Efforts are on in a Boston warehouse to figure out a way to reverse this change. An ambitious engineering project which aims at opening up a portion of the levee to funnel sediment into the Barataria Basin south of  New Orleans is being planned. The hope is that the new channel will transport and deposit enough sediment to rebuild part of the endangered delta. A scale model built in a warehouse near Boston is testing the efficacy of this idea.

Fascinating to read the various problems geologists and engineers have to deal with when grappling with modifying nature at this scale.

To Save Louisiana’s Vanishing Coast, Build a Mini Mississippi Near Boston.

Remembrance: Dr V.G. Phansalkar, Palaeontologist

In the February 2020 issue of the Journal of Geological Society of India, Anand Kale has written a very nice tribute to his mentor Dr. V.G. Phansalkar who passed away earlier in December 2019.  It captures very well both the professional aspects of Dr. Phansalkar's career and his endearing personal nature. Dr. Phansalkar was a paleontologist and a stratigrapher who taught with distinction at Banaras Hindu University, University of Pune (now Savitribai Phule Pune University) and Sholapur University ( renamed Punyashlok Ahilyadevi Holkar Solapur University) from 1962 until his retirement in 1999.

Photo credit: Anand Kale. 

I was fortunate to interact with him extensively when I was studying for my masters degree at the University of Pune . He was an original thinker with a penchant for asking that awkward question which you had not thought of or which you were hoping no one will ask. At our department seminars,we students always waited for that moment when Dr. Phansalkar raised his hand to inquire about some aspect of the presentation that he thought could be explored in a new direction. A spirited debate always followed! There was never any malice in his actions, just genuine curiosity and a wish to share his perspective.

During my time as a student in Pune, stratigraphy and sedimentary geology were subjects that were placed in two separate bins and taught as such. Stratigraphy deals with the way strata (sedimentary layers) are laid down and the relationships of bundles of strata across time and between those deposited in different locales at the same time. It is a hugely important subject, providing many of the organizing principles for piecing together the geologic history of a region. Unfortunately, Dr. Phansalkar did not get to teach us this subject. The lecturer who was assigned to teach it did a hack job of it with an insane emphasis on memorizing rock unit names from different parts of the country. Enlightenment came during our paleontology coursework. By interleaving palaeontology and stratigraphy in his lectures Dr. Phansalkar guided us towards understanding stratal layering patterns, sedimentary rock properties, and fossil occurrences as interrelated outcomes of the way sedimentary basins get filled up. I now realize it was an early jargon free introduction to sequence stratigraphy!

Years after my graduation from Pune, on a holiday from my PhD work in the U.S., I paid a visit to my old geology department.  In a conversation with Dr. Phansalkar I happened to mention that I was teaching sedimentary petrology as part of my assistantship duties. He looked at me for just a moment, leaned towards a drawer, and placed a box of limestone thin sections in my hand. Use these to teach he said. They were part of his precious collection of samples from the Cretaceous age sedimentary rocks exposed in the area around Ariyalur in Tamil Nadu. My lab benefited enormously from his thoughtful gift.

His home in Pune is quite close to where I live. In recent years we bumped into each other quite often during his evening walk in the park and on the nearby hill. Long geological stories peppered with humorous anecdotes became a welcome addition to my evening routine. I will miss that now that he is gone.

People often ask me why I took up science outreach. I have no hesitation in saying that it was in no small measure due to educators like Dr. Phansalkar who taught me that knowledge sharing is an immensely fulfilling endeavor to follow.