Darwin's Voyage Captured In Sketches And Watercolors

A nice article in the Guardian tells the story of Conrad Martens, an artist who accompanied Darwin for the first few years of his voyage to South America and beyond. Martens sketches and watercolors helped capture not just the lives of local people, landscapes and seascapes but shipboard and other research activity of crew and of Charles Darwin.

Now all this material has been put together in a digital archive accessible via the Cambridge University Library.

 Darwin's Christmas of 1833 with Martens drawing the activities seemed like fun times aboard the Beagle:

“After dining in the Gun-room, the officers & almost every man in the ship went on shore. – The Captain distributed prizes to the best runners, leapers, wrestlers. – These Olympic games were very amusing; it was quite delightful to see with what school-boy eagerness the seamen enjoyed them: old men with long beards & young men without any were playing like so many children. – certainly a much better way of passing Christmas day than the usual one, of every seaman getting as drunk as he possibly can.”

Its a a treat to go online and peruse through one of history's most epic voyages!

...Meanwhile  FINALLY! .. I  am in possession and eager to start Darwin- Life Of  A Tormented Evolutionist by Adrian Desmond and James Moore. I have heard and read so much about the book that I  am now afraid that I might be disappointed. Unlikely, since Darwin's life, work and times are a fascinating topic with many many treasures to mine.

Happy Holidays!

Post Permian Mass Extinction Size Reduction In Glossopteris Plant Lineages

Mass extinctions prune away branches of the tree of life. The late Permian-Triassic mass extinction event affected marine and terrestrial animal life severely, perhaps more than it affected terrestrial plant life. One common observation is that survivor species tend to be smaller bodied representatives of groups. This is known as the Lilliput effect.

A lot of attention has been paid to evolutionary trends in size during and post mass extinction in various animal groups. An interesting paper in Current Science (open access)  documents the Lilliput effect in one of the iconic terrestrial plant groups  of Late Permian -Early Triassic times; the seed fern Glossopteris.

From the paper:

Modern day high-resolution regional palaeoecological studies have proved the myth wrong, which stated that the mass extinction event had little macroecological or evolutionary consequence for terrestrial plants The early Triassic (Panchet Formation) in India witnessed more arid or semi-arid climate in comparison to the Permian. The early Triassic experienced greenhouse conditions with a warmer phase (Figure 6) due to global rise of temperature coupled with episodes of intense volcanism. The reduced size of the lamina is one of the strategies adapted by the plants during the adverse condition in early Triassic when there was indeed a shortage of essential nutrients in the soil, in addition to seasonal dry climate, irregular rainfall and widespread aridity. The leaves possessed cuticles with sunken stomata since the atmosphere during the early Triassic had higher levels of CO2 and lower O2levels (Figure 7). The Glossopteris flora of late Permian was adapted to temperate, cool and moist environments. The phenomenon of dwarfism as evidenced in Glossopteris has been observed only up to th e early Triassic, which is represented by the Panchet Formation. During the middle to late Triassic, typical Dicroidium flora associated with Lepidopteris takes over the preceding Glossopteris flora.

Records of plant fossils substantiate the evidence that numerous physiological, reproductive and behavioural traits enabled the smaller sized plant species to persist in extreme climatic conditions.

I didn't know there was a myth that mass extinctions have little macro-ecological or evolutionary consequences for terrestrial plants. Although, I do get the impression that studies of plant evolution get less attention in the media than animal evolution.

Report: Global Shale Gas Development And Water Availability

This is something that I have written about before in the context of shale gas development from Indian sedimentary basins. The availability of fresh water might set up conflicts with agriculture demands and limit exploitation of shale gas.

A report by the World Resources Institute on the global situation points out the same problem elsewhere in many areas of the world.

38 percent of shale resources are in areas that are either arid or under high to extremely high levels of water stress

19 percent are in areas of high or extremely high seasonal variability; and

15 percent are in locations exposed to high or extremely high drought severity.

Furthermore, 386 million people live on the land over these shale plays, and in 40 percent of the shale plays, irrigated agriculture is the largest water user. Thus drilling and hydraulic fracturing often compete with other demands for freshwater, which can result in conflicts with other water users. This is particularly true in areas of high baseline water stress, where over 40 percent of the available water supplies are already being withdrawn for agricultural, municipal, or industrial purposes.

China, Mexico, South Africa and India all have sedimentary basins with shale gas potential located in areas of high water stress i.e. extraction of either surface water and/or groundwater exceeds natural replenishment.

WRI Full Report On Shale Gas and Water Availability
WRI Executive Summary On Shale Gas and Water Availability

The report relies on EIA estimates of technically recoverable shale gas and tight oil. These numbers may be subject to revision as more detailed studies are taken up in sedimentary basins in India and other countries as well.

India is still some way away from exploitation of shale gas. It faces many other problems besides availability of water. This earlier post summarizes these issues.

Evolutionary History Of Insects

When the biologist J B S Haldane was asked if anything can be learned about the Creator from studying natural history, he is said to have quipped that "God has an inordinate fondness for beetles". There are about 300,000 species of beetles compared to 10,000 species of birds and about 5,400 species of mammals. Overall, there are about 1 million described species of insects and estimates range from 6 million to 10 million for the total number of living insects species. Insects may represent up to 90% of animal forms on earth.

Now a new genomic study aims at teasing out aspects of their evolutionary history such as the timings of their origin, the timing of winged flight and the timing of major diversification events. This is a big deal. On Science Friday, Michelle Trautwein from the California Academy of Sciences gives a lively presentation of this research. The amount of data used is staggering... a comparison of about 1500 genes. Working out evolutionary relationships and nodes of diversification.. essentially building an insect family tree took months of number crunching on supercomputers. Insects evolved from a lineage of crustaceans, an arthopod group that includes lobsters, crabs and shrimp. Segmented animals seem to be very speciose (propensity to evolve new species), dominating both marine and terrestrial ecosystems.

Here is the summary from the paper-

Insects are the most speciose group of animals, but the phylogenetic relationships of many major lineages remain unresolved. We inferred the phylogeny of insects from 1478 protein-coding genes. Phylogenomic analyses of nucleotide and amino acid sequences, with site-specific nucleotide or domain-specific amino acid substitution models, produced statistically robust and congruent results resolving previously controversial phylogenetic relations hips. We dated the origin of insects to the Early Ordovician [~479 million years ago (Ma)], of insect flight to the Early Devonian (~406 Ma), of major extant lineages to the Mississippian (~345 Ma), and the major diversification of holometabolous insects to the Early Cretaceous. Our phylogenomic study provides a comprehensive reliable scaffold for future comparative analyses of evolutionary innovations among insects.

Holometabolous insects are those that undergo metamorphosis, insect development is made up of 4 stages of egg, larva, pupa and adult.

Those who like to wade into the details check out the image below. I like the footer which places the evolution of different insect groups in the context of major geological events and plant evolution.

The earliest terrestrial vegetation on earth in the mid late Ordovician Period about 450-470 million years ago was mosses and lichen which hugged the ground. Correspondingly, the earliest insects were ground dwelling. As vegetation gained height by the Devonian Period, insects evolved the ability to fly. Co-evolution with plants is the common theme of the insect story of life. And these creatures are old ... old.. consider this that the extant lineages of mammals began diversifying only about 100 million years or so. All the major living groups of insects originated more than 300 million years ago. Sometimes our perspective of animal life on earth is skewed towards too much attention to mammals even though in antiquity and diversity insects do dominate.

Do listen to the talk on Science Friday. 

Early Chinese History Told Through Maps And Poetry

I am really enjoying Jerry Brotton's A History Of The World In 12 Maps. One richly rewarding chapter is on early Chinese map making traditions and inevitably you end up learning quite a bit of history as well.

The Song dynasty (907- 1276 AD) struggled with keeping the empire unified and intact and faced particularly strong challenges from the Jurchen Jin a confederacy of Tungusic tribes from northern Manchuria. In the middle of the 12th century the Song were forced to sign a peace treaty with the Jurchen Jin ceding to them nearly half their northern territory.

Subsequent imperial maps drawn up by the Song never showed this division. Rather, an idealized geography that the Song kept dreaming of based on earlier classical texts like Yu Gong, that of a unified empire to which foreign barbarian rulers paid tribute was portrayed. Using maps as a tool for political propaganda is an old trick! 

What maps did not depict though, poetic license did.

This beautiful passage from the book:

Poetry describing maps either side of the traumatic division of the Song also captures their power to first acknowledge, and then lament the loss of territory. Writing more than 100 years earlier, the ninth century Tang poet Cao Song describes 'Examining " The Map of Chinese and Non Chinese Territories"':

With a touch of the brush the earth can be shrunk;
Unrolling the map I encounter peace.

The Chinese occupy a prominent position;
Under what constellation do we find the border areas!

On this occasion the almost meditative act of unrolling the map and seeing a unified Chinese dynasty at its center evokes emotions of security and assurance. Later Southern Song poets used a similar conceit, but with very different emotions. Writing in the late twelfth century, the celebrated Lu You (1125-1210) lamented:

I have been around for seventy years, but my heart has 
remained as it was in the beginning, 
Unintentionally I spread the map, and tears come gushing forth.

The map is now an emotive sign of loss and grief, and perhaps a 'template for action', a call to unite what has been lost.

Meteorite Impact May Have Triggered Largest Pulse Of Deccan Basalt Eruptions

What caused the mass extinction 65 million years ago?

a) It was a meteorite impact and the resulting environmental crises.
b) No,  it was the Deccan basalt eruptions and the resulting environmental crises.
c) It was both, the meteorite impact and the eruptions.

The two mechanisms were distinct. One, a calamity from space and the other a gigantic eruption whose cause was from deep within the earth.

Now, it seems they may be more intimately linked. The meteorite impact may have triggered the largest pulse of the Deccan volcanic eruptions. Be careful here. The impact did not initiate Deccan volcanism. That was caused by India rifting away from Madagascar (88 mya) and Seychelles (66 mya). The rifting and an unusually hot mantle underneath resulted in copious amounts of melt being generated in the mantle which found its way to the surface via the great tensional cracks formed when continents separate. The impact though may have resulted in increasing the permeability of the mantle underneath thus making it possible for larger amounts of magma to make its way to the surface.

Abstract- 2014 GSA Annual Meeting, Vancouver:

New constraints on the timing of the Cretaceous-Paleogene (K-Pg) mass extinction and the Chicxulub impact, together with a particularly voluminous and apparently brief eruptive pulse toward the end of the “main-stage” eruptions of the Deccan continental flood basalt province, suggest that these three events may have occurred within less than about a hundred thousand years of each other. Partial melting induced by the Chicxulub event does not provide an energetically-plausible explanation for this coincidence, and both geochronologic and magnetic-polarity data show that Deccan volcanism was underway well before Chicxulub/K-Pg time. However, historical data document that eruptions from existing volcanic systems can be triggered by earthquakes. Seismic modeling of the ground motion due to the Chicxulub impact suggests that the impact could have generated seismic energy densities of order 0.1-1.0 J/m3 throughout the upper ~200 km of the Earth’s mantle, sufficient to trigger volcanic eruptions worldwide based upon comparison with historical examples. Triggering may have been caused by a transient increase in the effective permeability of the existing deep magmatic system beneath the Deccan province, or mantle plume “head.” It is therefore reasonable to hypothesize that the Chicxulub impact might have triggered the enormous Poladpur, Ambenali, and Mahabaleshwar (Wai sub-group) lava flows that account for >70% of the Deccan Traps main-stage eruptions. This hypothesis is consistent with independent stratigraphic, geochronologic, geochemical, and tectonic constraints, which combine to indicate that at approximately Chicxulub/K-Pg time a huge pulse of mantle plume-derived magma passed through the crust with little interaction, and erupted to form the most extensive and voluminous lava flows known on Earth. High-precision radioisotopic dating of the main-phase Deccan flood basalt formations may be able either to confirm or reject this hypothesis, which in turn might help determine whether this singular outburst within the Deccan Traps (and possibly volcanic eruptions worldwide) contributed significantly to the K-Pg extinction.

Elsewhere in a GSA special issue on volcanism, impacts and mass extinctions more evidence that Deccan volcanism had a significant impact on the fauna and flora.

Chronology of the volcanic episodes is improving and pointing to a scenario wherein the volcanism coincided (or was causally connected) to within a hundred thousand years of the Chicxulub impact and overlapped the stratigraphic horizon defined as the Cretaceous -Paleogene boundary. Looks like everyone is going to be partially right on this one.

Multiple causes for the mass extinction.

A Small Note On Animal Fossils Before The Cambrian "Explosion"

Every now and then there appears a news story about metazoan fossil findings that expresses great astonishment and surprise that there is NOW... THIS TIME.. new evidence that multicellular animals evolved long before their celebrated preservation in the Chengjiang and Burgess shale Lagerstatte.

But we have known that for a long time.  The Neo-Proterozoic and early Cambrian fossil record is so much better and is improving and paleo-biologists and palaeontologists have recognized in it the gradual increase in complexity of metazoans over a 50-60 million year period before the exceptional preservation windows of Chengjiang and Burgess shale gives us a false impression of a sudden appearance of complex multicellular animals. This artifact has been exploited by creationists who claim that the fossil record actually supports their creation story of a sudden origin, under some intelligent guidance, of complex animals in the Cambrian, summarized in books like Darwin’s Doubt: The Explosive Origin of Animal Life and the Case for Intelligent Design. The best rebuttal I have come across of the creationists many misunderstandings of early animal evolution is this excellent article by Nick Matzke.

Let me just post this invaluable figure below which summarizes the Neo-Protoerozic - Cambrian metazoan fossil record. This is from James Valentine's book On The Origin Of Phyla.  It shows clearly that metazoan complexity and diversity increased gradually over time. Molecular phylogeny which aims to reconstruct the last common ancestor of animals based on genetic similarities and differences also tells us that the origin of multicellular animals goes back at least 600 million years ago, maybe even more, a good 80-100 million years before the evolution of calcium carbonate skeletonization made their existence obvious in early Cambrian. Next time a news item appears that claims that somehow fossil embryos or fossil burrows from the Neo-Proterozoic times are some shocking new finding that will change our understanding of animal evolution - don't believe it.

Source: On The Origin Of Phyla

How Are Diagenetic Studies Useful In Understanding Sedimentary Basin History

I dusted of my PhD dissertation last week for two reasons. A friend insisted that she wanted to see my research.. and then this paper in the Journal of Sedimentary Research (behind paywall):

Diagenetic Evolution of Selected Parasequences Across A Carbonate Platform: Late Paleozoic, Tengiz Reservoir, Kazakhstan by J. A. D. Dickson and J. A. M. Kenter

The work is eerily similar to what I did for my PhD which was carrying out a detailed study of cementation patterns in Middle and Late Ordovician carbonate parasequences from the southern Appalachians.

Dickson and Kenter use petrographic techniques along with cathodoluminescence to tease apart the cementation sequence and pore space modification of the carbonate rocks. Hydrocarbon reservoir quality depends in part on how reaction of sediment with water either dissolves material to create pore space or precipitates cements to modify pore space. So, understanding the timing of these events in the context of the burial history of the sediment pile on a basin wide scale can help geologists predict reservoir quality.

Ok, so what are Parasequences?

Cool! 3D Printing In The Geosciences

Geological  Fabrication Laboratory!.. Yes.. the future is already here.

and it is run by Franciszek Hasiuk of Iowa State University. He explains in a short note in GSA Today just why 3 dimensional  printing is so useful especially in the geosciences:

In the geosciences, we struggle with a fundamental problem—we love nature, but its aspects can be truly enormous or fantastically miniscule, very far away or exceedingly rare. Our burden is to overcome these conditions and communicate effectively about nature. With equal ease, 3-D printing can make hand-samples out of subduction zones and foraminifera, Martian topography, and seismic data.

Such models are immediately useful because much of what we need to communicate concerns shape and form (Fig. 1). For these purposes, we can produce inexpensive teaching models on demand, saving acquisition costs while bringing unique specimens to broader audiences. Three-dimensional printing makes the natural specimen the starting point. Digital models can be transformed (e.g., scaled, mirrored, distorted) by an instructor or a student to explore concepts like morphology, vertical exaggeration, or strain. With a little CAD work, we can make flexible fossils to more effectively communicate how organisms, extinct and extant, locomote.

Students might more easily develop a sense of scale from a touchable topography—that they themselves choose and print—that combines local elevation data showing natural and human features. By printing in multiple colors, geological attributes (like geologic formations or geophysical measurements) can be printed over elevation data as a way to better understand a new field area or check field results.

There is more about the applications of 3D printing in understanding rock pore networks with applications in the oil industry this Science Daily article.

Fascinating..

Remotely India # 7: Mesozoic Domes Of The Kachchh Basin

Remotely India # 7

A recent paper in Current Science (open access) on the geomorphology and tectonics of domal structures in Mesozoic strata prompted me to resurrect this old series titled Remotely India. In these posts I put up a satellite image(s) of an interesting geological feature somewhere in India followed by a brief explanation.

Today's post is on the Kachchh basin in western India. In Mesozoic times this region was a long lasting marine basin in which hundred's of feet of sediments accumulated. Occasionally the sea withdrew and fluvial and lacustrine deposits formed. But most the sedimentary sequence represents marine conditions. Over much of the region the sedimentary strata are horizontal to very gently dipping in disposition indicating very little tectonic disturbance of the basin since the Mesozoic.

At places though these Mesozoic sedimentary rock has been upwarped into domes. These appear as a linear series of blisters in the landscape. The observation that they occur in a linear arrangement is significant and geologists have understood that these blisters and domes occur along mostly east-west trending faults. Map below show the geomorphological and tectonic elements of the region. Red cross is the town of Bhuj.

Source: Kachchh Mesozoic Domes, Current Science 

And this image below is of the Habo dome near the town of Bhuj.

Observations reveal that these domes show an antiformal structure with diverging dips i.e. beds (strata) bending or dipping outwards from the core area.

Here is a series of  domes (Dudhai domes) east of the town of Bhuj.

How did these structures form? Geologists reasoning is as follows: a) The domes don't have corresponding basin like structures, so they did not form through compressional forces buckling the crust into swells and depressions b) the domes occur in Mesozoic rocks on the uplifted blocks of faults but they are not found on the other side of the fault blocks. This suggests that the domes are not "drape folds" formed by vertical movement and adjustment of the sedimentary blanket during faulting. Also supporting the view that faulting did not form the domes is the observation that at places the domes are truncated by faults indicating that this type of structural disturbance occurred much later than the formation of the domes.

Image below shows a truncated dome north of the town of Bhuj

c) there is a close association of magmatic bodies of mafic and ultra-mafic composition with the domes. In some domes plug like magmatic bodies occur in the core of the domes. At places small dykes and stringers of magma are seen to dart from the main magmatic body into the sedimentary beds. This indicates that the magmatic bodies intruded the sedimentary rocks. Based on this the best explanation geologists feel is that these domes formed when magma rose through the crust and impinged the base of the Mesozoic sediments causing bending and doming of the rocks.

When did this occur?  Since Mesozoic times as Gondwanaland split apart into fragments forming the western margin of India, the Kachchh region has been subjected to extensional forces which resulted in several rift type basins forming there. East West trending faults and fracture systems are typical structural elements of this region since the mid Mesozoic.  Radiometric dating says the magmatic intrusions into these sedimentary rocks took place about 68 mya to 64 mya (million years ago).  This was just before and overlapping the Deccan volcanism in the Late Cretaceous which suggests that during magmatic episodes molten material was channelized along older fracture and fault systems of the Kuchchh region resulting in a localization of the domes along faults.

Topographic features, the undulations and swells and mountains that wrinkle the earth's crust form in the variety of ways. Classic orogenic mountains like the Himalayas form when tectonic plates collide and deform and thicken and lift up the earth's crust along thrust faults. Prolonged explosive outpouring of lava can form the beautiful yet deadly mountains like Vesuvius, Mount St. Helens and Mount Fuji. Yet, quieter outpouring of lava like the one experienced during Deccan volcanism can form enormous piles of lava. This pile can later be affected by gentler vertical movements of the crust coupled with differential erosion, forming a landscape of cliffs and gorges as seen in the Western Ghats... and sometimes magma ascends and pushes the crust upwards to form blisters like the domes of Kachchh. Coincidently, David Bressen has a blog post on the history of the idea of plate tectonics. Before this theory explained the origin of large mountain chains, the prevailing view was that mountains are blisters and bumps formed by magma pushing the crust from underneath..!!

Interactive Map:

Quote: Steven Pinker On Education

The Ivy League admissions process comes under Steven Pinker's critical eye. It should be more meritocratic and less "holistic" he thinks. I liked this passage on the role of education:

It seems to me that educated people should know something about the 13-billion-year prehistory of our species and the basic laws governing the physical and living world, including our bodies and brains. They should grasp the timeline of human history from the dawn of agriculture to the present. They should be exposed to the diversity of human cultures, and the major systems of belief and value with which they have made sense of their lives. They should know about the formative events in human history, including the blunders we can hope not to repeat. They should understand the principles behind democratic governance and the rule of law. They should know how to appreciate works of fiction and art as sources of aesthetic pleasure and as impetuses to reflect on the human condition.

On top of this knowledge, a liberal education should make certain habits of rationality second nature. Educated people should be able to express complex ideas in clear writing and speech. They should appreciate that objective knowledge is a precious commodity, and know how to distinguish vetted fact from superstition, rumor, and unexamined conventional wisdom. They should know how to reason logically and statistically, avoiding the fallacies and biases to which the untutored human mind is vulnerable. They should think causally rather than magically, and know what it takes to distinguish causation from correlation and coincidence. They should be acutely aware of human fallibility, most notably their own, and appreciate that people who disagree with them are not stupid or evil. Accordingly, they should appreciate the value of trying to change minds by persuasion rather than intimidation or demagoguery.

I believe (and believe I can persuade you) that the more deeply a society cultivates this knowledge and mindset, the more it will flourish. The conviction that they are teachable gets me out of bed in the morning.

Do read the entire article.

Human Evolution - Out Of Africa, Assimilation, Multi-Regionalism

So much has happened in the field of human evolution in the last few years!

Two end member theories have been popular for some time. The Out Of Africa theory says that modern humans originated in Africa around hundred thousand years ago and then spread all over the world replacing local populations of humans from older migrations. On the other hand the multiregional scenario said that modern humans did not originated exclusively in Africa. Rather modern humans evolved from local populations everywhere i.e. eg. modern Chinese evolved from Homo erectus  (which migrated there from Africa several hundred thousand years ago) in China with some gene flow between regions.

That extreme multiregionalism has now been rejected by recent advances in understanding genetic relationships between human populations but in a way so has the extreme Out of Africa version. There is evidence now that modern humans interbred with older regional populations as they spread across the world. This is now termed Out of Africa with assimilation or as "leaky replacement" by some.

Chris Stringer a researcher at the Natural History Museum London writes a good summary of the various theories of modern human origins. It is open access and worth reading.

A short excerpt:

 ‘Modernity’ was not a package that had a single African origin in one time, place, and population, but was a composite whose elements appeared, and sometimes disappeared, at different times and places and then coalesced to assume the form we see in extant humans [6]. However, during the past 400 000 years, most of that assembly took place in Africa, which is why a recent African origin still represents the predominant (but not exclusive) mode of evolution for H. sapiens. Rather than saying ‘we are all multiregionalists trying to explain the out-of-Africa pattern’ [1], it would be more appropriate to say ‘we are all out-of-Africanists who accept some multiregional contributions’.

On The Consequences Of A One To One Scale Map

 My Book Shelf # 30

I have just started reading A History Of The World In Twelve Maps by Jerry Brotton, an exploration of influential maps through our history that shaped the way we viewed the world and in turn how our cultural habits, religious beliefs and political power equations of the day shaped decisions of how and what to represent. Each period in our history argues Jerry Brotton gets the map it deserves. It promises to be a really interesting read.

Early in the introduction I came across this passage on the use of scale:

The only map that can ever completely represent the territory it depicts would be on the effectively redundant scale of  1:1. Indeed, the selection of scale, a proportional method of determining a consistent  relationship between the  size of the map and the  space it  represents is closely related  to the problem of abstraction, and has been  a rich source of pleasure  and  comedy for many writers. In Lewis Carroll's Sylvie and Bruno Concluded (1893), the other worldly character Mein Herr announces that 'we actually made a map of the country, on a scale of  a mile to the mile!' When asked if the map has  been used much,  Mein Herr admits, 'It has never been spread out'. and 'the farmers objected: they said it would cover the whole  country,  and shut out the  sunlight! So we now use the country itself, as its own map, and I assure you it does  nearly as well.' The conceit was taken a stage further by Jorge Luis Borges,  who, in his one-paragraph short story 'On Rigour in Science' (1946), recast Caroll's account  in a darker key. Borges describes a mythical empire where the art of mapmaking  had reached such a level of detail that 

the Colleges of Cartographers set up a Map of the Empire which had the size of the Empire itself and coincided with it point by point. Less Addicted to the  Study of Cartography, Succeeding Generations understood that this widespread Map was useless and with Impiety they abandoned it to the Inclemencies of the Sun and of the Winters. In the deserts of the west some mangled Ruins of the Map lasted on, inhabited by Animals and Beggars; in the whole Country there are no other relics of the Disciplines of Geography.

Borges understood both the timeless quandary and potential hubris of the mapmaker: in an attempt to produce a comprehensive map of their world, a process of reduction and selection must take place. 

Wonderful passage! (but i wonder not having  read the story -if the map was as large as the empire, where did they keep it? :) )  If you want a shorter summary of the book do listen to Jerry Brotton on BBC Pop-Up Ideas podcast -  Mapping History. It is an enjoyable talk.

Now,  back to reading!

Conversation With An Ecologist About Fossils And Conservation

T R Shankar Raman, an ecologist who blogs at View At Elephant Hills and tweets @mizoraman wrote in last week with a question about fossils, field work and conservation. It ended up being a long conversation via email and so with his permission I am posting our conversation below.

In geology, field sampling does lead to outcrops being damaged and in-situ context of important fossils being lost. At least when I was a student, these issues about how to go about working an outcrop so as to cause least damage to the outcrop and what are the ethics of fossil collection did not come up for any discussion. Do faculty discuss this with students these days here in India?  I don't see these issues being widely discussed in the geology community here. I will be talking to a palaeontologist to get her views about the legality and ethics of collecting fossils from private and public lands in India which I will write up as a blog post.

In the meantime, below is our exchange.

Shankar Raman-

if you have the time. If geologists find something like this, how do they decide whether to leave it in situ (conservation) or remove (collection) for study? How many of the scientific collections are then actually subject to study and make it into publications and how many are simply lost? If locations of such fossils are made public/advertised, does it lead to their loss or a kind of vandalism? (I ask because there are parallels from ecology/field biology of collecting animal or plant specimens and related ethical and conservation concerns.)

Suvrat Kher

you raise interesting and important issues. I do feel conservation issues in the sense of leaving fossils or minerals in situ have not been widely discussed in the geology community yet. On a broader scale geologists do agree that some sites are of great importance as a geological heritage and those should (and some are) conserved. The Geological Survey of India is working of an expanded list of geological sites that they will ask for protected status. But at an individual level, a geologist or palaeontologist working in a field area is likely to sample whatever is available (the feeling may be that someone else would sample it and scoop my research :) ).

Regarding whether fossil collections go unstudied, the answer is the age-old "it depends" on who did the collecting and when. For example the GSI has enormous collections of fossils from more than a century of mapping the country. Much of these lie in museums and archives, unstudied, although some GSI geologists do describe them in monographs and such. But more value addition in terms of their ecological and evolutionary significance remains to be done.

On the other hand academic departments have shorter term goals, limited funding and a pressure to publish (esp in recent times). Their sampling programs hence tend to be limited and focused and much if not all of the fossils eventually will be published. In some cases though palaeontology departments are on the wane and so yes their collection may remain unstudied.

In terms of keeping fossil sites secret, not sure how that will work. If you publish then the location has to be disclosed. That is scientific practice. Vandalism however is a real threat and is happening with private collectors making of with a bounty (example minerals like zeolites found around Pune are providing a fortune for dealers). I guess one can't protect the entire sedimentary basin but demarcating protected areas and provided funds to secure such sites is the best one can hope for. Perhaps we need to make a distinction of collecting fossils from private lands (with permission) versus protecting public sites which fall within National Parks and such. The U.S has such a distinction.  In any case unfortunately this is not given enough importance and if there is a law against collection nobody seems to be aware (including me!) of it and am sure it is widely disregarded.

thanks for making me think aloud about these issues!

Shankar Raman-

Thanks for your thoughtful response. I see the parallel concerns and differences that you describe. In our field of work, there are serious concerns regarding (a) collection of specimens (a significant number languish without final description with scientists who dont want to be scooped and dont want to share or deposit in museums), (b) possible impacts on the habitat and the population of the species in the area where the study or collection is carried out. So it is a matter of both ethical and conservation concern.

And this is not just restricted to India... listen to this NPR broadcast for instance, triggered by a paper in Science: http://www.npr.org/2014/06/18/318307574/is-collecting-animals-for-science-a-noble-mission-or-a-threat

In our field (wildlife conservation), there is also the related issue of tourism in natural areas and other threats such as poaching. So we always try to be careful and sometimes decide to not disclose a specific location of an endangered species (a rare orchid, say, the nest of a breeding hornbill, or a wild male elephant with huge tusks) or do so after some kind of embargo period or with less specific geographic coordinates. Striking a balance is tricky... one does not want to end up with a situation that further stifles genuine research and also creates more bureaucratic red-tape for permits.

Hence my email and reticence regarding specific details about the fossils before I understand how things play out in geology. About law: the Indian wildlife act does prohibit removal of plants, animals (even dead, body parts etc) or destroying habitat in any way. But if someone chips away a bunch of fossils or pockets/bags a few... will they be caught? If caught, will they be fined or acted against? No idea! You should do a blog post about this someday! Conservation is a general enough word to be relevant to artistic heritage, geology, and
wildlife!

Thanks for the discussion!

In Darwin's Footsteps: A Book On The Galapagos Daphne Major Finches

Years ago I read Jonathan Weiner's excellent book The Beak Of The Finch. He describes the work of Peter and Rosemary Grant on the finches of Galapagos Islands with its fertile volcanic landscapes and biodiversity having inspired another aspiring naturalist in the 1830's to great discoveries. The Grants studied for decades evolution of finch populations, observing in them natural selection in action.

Now they have written their own book- 40 Years of Evolution: Darwin's Finches on Daphne Major Island.

Jonathan Weiner writes about it in the New York Times:

They kept up their watch during years of downpours and years of drought — seasons of feast and famine for the finches. And Darwin’s process unfolded before their eyes in intense episodes that illustrated better than anything in the Origin the struggle for existence, and the ways that life adapts and emerges fitter from the struggle.

.. and on the possible beginnings of a distinct lineage -

Big Bird’s lineage has now lasted for 30 years and seven generations. The Grants are cautious about its prospects — “It is highly unlikely that we have witnessed the origin of a long-lasting species, but not impossible,” they write — but other scientists are buzzing.

This is exciting work, the stuff that inspires young students of the subject to push ahead with their own dreams and aspirations. The Grants are both 77 years young now... and still studying their beloved finches.

Some Interesting Podcast's I've Listened To Recently

I should be sharing this list more often-

1) On America's other migrant farm workers - Bees! Biologist Laurence Packer talks about the importance of bees in American agriculture. Incredible- millions of them are transported by trucks to aid in pollinating almonds and other fruit crops from one end of the U.S to the other!

2) Science Friday- Summer Book List 2014- What is not to like about a conversation that discusses a book like Proof- The Science of Booze!... and many more books featured in this talk.

3) Science Friday- Crafting Perfect Beer- more on the microbiology of beer and the burgeoning craft beer industry in the U.S.

4) Planet Money- The History of Light: Before there was the light bulb there was fat! Planet Money is one of my favorite podcast; it is economics explained with a light touch. This episode features how we got from candles made from cow fat and whale blubber to light at the flick of the switch and its economic implications in terms of the massive increase in human work productivity.

5) On Point Radio- The End of Night: A nostalgic look at what we have lost with our city life- the end of the night sky. Wonderful remembrances by callers too.

6) Fresh Air: To End All Wars: Its the 100th anniversary of the beginning of the Great War (World War I) and author Adam Hochschild discusses his book To End All Wars- you read this with a shudder- " I think the war remade the world for the worse in every conceivable way: It ignited the Russian Revolution, it laid the ground for Nazism and it made World War II almost certain. It's pretty hard to imagine the second world war without the first."

Bahama Carbonate Precipitation Triggered By Saharan Dust

Interesting paper in Geology : The fertilization of the Bahamas by Saharan dust: A trigger for carbonate precipitation? - P.K. Swart, A.M. Oehlert, G.J. Mackenzie, G.P. Eberli and J.J.G. Reijmer

Abstract

The enigma of the Bahamas is that this highly productive carbonate system has existed for at least 100 m.y., building a vast edifice of carbonates, thousands of meters thick, in an essentially nutrient-poor environment. Based on measurements of the insoluble material, the Fe and Mn in the carbonate fraction, and the δ15N of the sedimentary organic matter, we suggest a paradigm shift in order to explain the formation of the Bahamas and possibly other similar platforms. We propose that the Great Bahama Bank is currently, and may in the past have been, fertilized by atmospheric dust, promoting the fixation of atmospheric N2 by cyanobacteria. These cyanobacteria provided a source of nitrogen to the rest of the community in this nutrient-poor environment. The fixation of N has imparted a characteristic δ15N signal and has been responsible, through the drawdown of CO2, for initiating the precipitation of carbonate in the shallow waters. This phenomenon might be responsible for the formation of vast amounts of sediments in the oceans, not only within recent times, but throughout geological history, particularly in the early history of the Earth prior to the existence of calcium carbonate–secreting organisms.

Many carbonate sedimentologists suspect that microbial activity has played an important role in carbonate sediment precipitation and this paper provides more evidence for it from a familiar setting. The geology of the Bahamas has been extensively studied but sometimes basic questions remain "Why such  prolific sediment production by organisms in a nutrient poor environment?".  The answer in this case may be an exogenous source of nitrogen. Whether this is a more general explanation remains to be answered. There may be other controls, for example in the Proterozoic sea water chemistry was different with elevated levels of calcium carbonate saturation. This means that there were lots of Ca and CO3 molecules available to aggregate as CaCO3 crystals. This enabled -with and without the aid of microbial activity-  vast deposits of carbonates to accumulate.

Geology Ignored In The Planning And Building Of Himalayan Dams

In Current Science K.S Valdiya explains (Open Access):

It will be obvious from the distribution of dam locations (Figure 1; Tables 3–6) based on information culled from reports of Central Electricity Authority, Uttara-khand Hydroelectricity Nigam, Uttarakhand Renewable Energy Development Authority, etc. that the existing hydroelectric projects and those that are under construction or planned are sited close to the terrane-defining thrusts known to be active. The sites were chosen presumably in the narrowest stretches of the river valleys, little realizing that the otherwise wide valleys with gentle valley sides become narrow with steep to nearly vertical walls due to uplift of the ground and attendant accelerated riverbed erosion as explained earlier. The ground rises as a conse-quence of upward movement on active faults/thrusts (Figure6). Moreover, the belts of active faults are made up of deformed rocks –many-times folded, sheared, shattered an even crushed rocks. These rocks understandably easily break-up, fall -off, creep and slide or slump down when excavated or shaken by earthquakes and explosions,and sink under loads. These incidences are bound to pose a threat to the various structures built in the project areas.

The development of hydroelectric projects not only entails excavations for the head race dams and associated coffer dams, diversion tunnels, main tunnels for carrying water to turbines, and multitudes of adits, but also for thenetwork of roads, for residential colonies for work force,and for power generators. Obviously, a dam site–nomatter if it is just a small one–is excessively subject to tampering with the natural balance in a zone of very weakened rocks.

Reactivation of the active thrusts is bound to impact the stability of the engineering structures. One of the impacts could be the displacement or disruption of the structures due to sudden release of stress that the thrust movements entail. The effects on the tunnels associated with dams would be far more severe – there would be dis-ruption or offsetting of tunnel, roof collapse, sudden on-rush of interstitial groundwater with crushed material,and severe damage to tunnel lining. The very making of a tunnel is like opening an underground drainage and thus altering the groundwater regimes of the mountains, resulting in drastic lowering of groundwater table and at tendant drying up of springs and dwindling of surface flow in streams.

Figure 1 is self-explanatory. Needless to state that a large number of existing and planned hydroelectric projects are bound to encounter serious problems, particularly if and when movements take place on the thrusts in the proximity of the project locations.

Uttarakhand has plans for 180 big and small hydroelectric projects with 95 dams in the middle and upper reaches of the Alaknanda and Bhagirathi rivers in the vicinity south of the Main Central Thrust. K.S Valdiya suggests that the sites should be chosen preferably north of the Main Central Thrust in regions with much lower population density which will lead to less environmental, social and economic problems. The current government has indicated that it will lean towards rapid environmental clearances for infrastructure projects, so just how much attention will be given to warnings like this one?

A Survivor From The Namib Desert

This beautiful passage from Robert Krulwich's essay on the plant Welwitschia mirabilis, a survivor, the last representative of its genus, isolated and endemic to the Namib desert in South Africa:

Welwitschia, when you finally get to see one, sits apart. It's very alone. All its relatives, its cousins, nieces, nephews have died away. It is the last remaining plant in its genus, the last in its family, the last in its order. "No other organism on earth can lay such a claim to being 'one of its kind,' " writes biologist Richard Fortey. It comes from a community of plants that thrived more than 200 million years ago. All of them slowly vanished, except for Welwitschia. It has survived by doing very little, very, very slowly — sipping little wafts of dew in the early mornings, otherwise minding its own business, as the big, busy world goes by.

With much recent attention given to the question of de-extinction i.e. bringing back extinct species, a more urgent focus needs to be on species and populations which are alive today and hanging by a thread. Genetics will play a role here too along with old fashioned conservation of the ecology in which these creatures persist despite all odds.

Sherlock Holmes And Long Term Evolutionary Patterns In Dinosaur Body Size

This week's (in Pune, India) Sherlock Holmes Elementary featured a murder mystery involving a smuggled dinosaur fossil. The fossil is believed by some palaeontologists to be entombed in rocks of the earliest Paleocene, making that dinosaur a survivor of the end Cretaceous mass extinction. Other palaeontologists strongly disagree with this survivor fauna scenario, which the drama turns into a motive for murder. There was a fair amount of geology and palaeontology in the episode and a reference to a term "dead clade walking".  This term is real life was coined by David Jablonski a palaeontologist from University of Chicago.  The term means that a clade or a lineage has survived a mass extinction but its fate has been sealed. Over a period of time say a few million years after the mass extinction that group does eventually go extinct.

Some dinosaur species may have survived the mass extinction but by early Palaeocene they were certainly all gone... except one lineage.. the Availea or birds. They prospered in the Cenozoic, radiating into a hundreds of species. Their success may have had deep roots and one important factor may have been the small size of their ancestors.

A paper in PLOS Biology explores the long term evolutionary patterns of dinosaurs and finds a positive relationship between high rates of evolution and small size-

Rates of Dinosaur Body Mass Evolution Indicate 170 Million Years of Sustained Ecological Innovation on the Avian Stem Lineage:

Author Summary

Animals display huge morphological and ecological diversity. One possible explanation of how this diversity evolved is the "niche filling" model of adaptive radiation—under which evolutionary rates are highest early in the evolution of a group, as lineages diversify to fill disparate ecological niches. We studied patterns of body size evolution in dinosaurs and birds to test this model, and to explore the links between modern day diversity and major extinct radiations. We found rapid evolutionary rates in early dinosaur evolution, beginning more than 200 million years ago, as dinosaur body sizes diversified rapidly to fill new ecological niches, including herbivory. High rates were maintained only on the evolutionary line leading to birds, which continued to produce new ecological diversity not seen in other dinosaurs. Small body size might have been key to maintaining evolutionary potential (evolvability) in birds, which broke the lower body size limit of about 1 kg seen in other dinosaurs. Our results suggest that the maintenance of evolvability in only some lineages explains the unbalanced distribution of morphological and ecological diversity seen among groups of animals, both extinct and extant. Important living groups such as birds might therefore result from sustained, rapid evolutionary rates over timescales of hundreds of millions of years.

In general the rapid-evolvers would be the smallest-bodied species -- the ones that reach reproductive age quickly and while they are still small. Rates of evolution depend on generational time. Which predicts that large-bodied/long-generation-time species would have more difficulty adapting to rapidly-changing extinction conditions.

The authors also mention that body size evolution in many non-avian dinosaur lineages seem to follow Cope's Rule, an increase in body size of descendant species over time. The earliest species in that lineage would be small and over time there would be a trend towards evolution of larger bodied species.

What could cause such a trend? Is larger body size advantageous and hence being favored by natural selection? Again the relationship to mass extinctions is intriguing. The authors mention that during the late Triassic mass extinction many branches of dinosaurs became extinct. If larger bodied dinosaur species were disproportionately killed off the survivor species of dinosaurs in early Jurassic would have been small bodied. This could explain Cope's Rule in a rather novel way (as explained by my adviser Anthony Arnold - who has worked on size evolution in foraminfera - in an email to me) - "since it means that rather than evolution favoring size increase, mass extinction selectively removes larger-bodied species, leaving behind the smaller guys as survivors. Since they don't have much room to get smaller the survivors could even speciate at random and the only direction in which the variance has room to expand is toward larger size.

Maybe!.. arm waving.."

So ecological crises may lead to species sorting based on size with smaller size being favored and then evolution of a trend towards larger size that reflects simply an inability to become any smaller!..
 

Book- John Tyler Bonner- Randomness In Evolution

This book is surely worth reading. Randomness in Evolution by John Tyler Bonner. I have loved Bonner's  previous books The Evolution of Complexity and Life Cycles. This promises to be interesting too.

In Current Science Raghavendra Gadagkar gives a positive review. The main premise of the book is that morphologies of unicellular eukaryotes like radiolarians and diatoms to give two examples are neutral phenotypes. That means that the variation of size, shape, ornamentation on skeletal material did not become common because it contributed to reproductive fitness. Rather for example different shapes were selectively neutral i.e. that is they neither gave the organism any advantage over another shape nor a disadvantage. One of the shapes became common just by chance, through random genetic drift.

Size according to Bonner is an important constraint on whether natural selection or drift becomes important in shaping morphology. Randomness is more important in small organisms with relatively simple genetic controls on morphology, while natural selection is more important in larger organisms with elaborate interlocking developmental steps.

I'll reserve comments until I have read the book but just would like to point out that even small unicellular eukaryotes have very sophisticated cellular machinery for processes like photosynthesis and regulating cellular functions. These would have evolved via natural selection.

Earthquakes Triggered By Fluid Injection Along Faults

A friend sent me this abstract published in the Seismological Society of America 2014 annual meeting-

Triggered Earthquakes Far From the Wellbore: Fluid Pressure Migration and the 2008-2014 Jones Swarm, Central Oklahoma

KERANEN, K. M., Cornell University, Ithaca, NY, USA, keranen@cornell.edu; WEINGARTEN, M., University of Colorado, Boulder, CO, USA, matthew.weingarten@gmail.com; BEKINS, B., USGS, Menlo Park, CA, USA, babekins@usgs.gov; GE, S., University of Colorado, Boulder, CO, USA, Ges@colorado.edu; ABERS, G. A., Lamont-Doherty Earth Observatory, Palisades, NY, USA, abers@ldeo.columbia.edu

Earthquake relocations and hydrogeologic modeling show that the Jones earthquake swarm, occurring near Oklahoma City since 2008, is linked to disposal wells injecting high volumes of water along the Nemaha Fault. Felt and recorded earthquakes in the Jones swarm began in 2008, approximately 15 km from four high-volume wastewater disposal wells. These wells dispose of ~2-3 million barrels per month (4-5 million barrels per month cumulatively) in two adjacent locations on the downthrown side of the Nemaha fault. Earthquakes are observed to migrate away from these high-volume disposal wells up the structural dip and down hydraulic gradient. Hydrogeologic modeling shows that the increase in subsurface pore pressure resulting from the fluid injection is of sufficient magnitude to trigger slip on pre-existing faults. The region of increased pore pressure grows outward through time with injection. The larger, mapped faults in the subsurface may act as conduits or guides to fluid flow, and may transmit fluid pressure into basement. Our results demonstrate that wastewater disposal can raise fluid pressure and trigger earthquakes at tens of kilometers from the wellbore on existing faults.

Fracking for shale gas by itself has not been shown to trigger biggish earthquakes but the wastewater disposal that follows fracking has.

How does increasing pore pressures increase the chances of slip along a fault? High pore pressures reduce the effective normal stresses acting perpendicular to faults. These normal stresses resist shear movements i.e. fault blocks from sliding past each other. With increased pore pressure the effective normal stresses decreases, allowing shear movements.  Geophyicist Mark Zoback explains in more detail about the risks and management of seismic risk posed by wastewater disposal.

India's Epic Geological Journey From Jurassic To Present

A friend mailed me this paper - The longest voyage: Tectonic, magmatic, and paleoclimatic evolution of the Indian plate during its northward flight from Gondwana to Asia by Sankar Chatterjeea, Arghya Goswamib and Christopher R. Scoteseb published in Gondwana Research and asked if I could give it a "Rapid Uplift" treatment.

I would love to write about this paper but it is too long for one post. I want to break it down to manageable substories and write a few posts on it. The good thing about the paper is that it describes the various geologic events using excellent graphics. So I hope to keep the posts relatively light on text and let diagrams and pictures tell the story.

Let me begin with this timeline of events- a summary of the tectonic, magmatic and paleoclimatic evolution of the Indian plate as it broke away from Gondwana, acquired a distinct physical shape and drifted northward towards Asia.

Source:  The longest voyage: Tectonic, magmatic, and paleoclimatic evolution of the Indian plate during its northward flight from Gondwana to Asia by Sankar Chatterjeea, Arghya Goswamib and Christopher R. Scoteseb

Its a very clearly worded summary of the long geological history of the Indian plate. .. more stories to follow soon!

Metazoan Embryos From Terminal Neo-Proterozoic Early Cambrian Himalayas

In Current Science Sabhyasachi Shome et al  and in Journal of Geological Society of India V.K Mathur et al report fossilized cellular remains in phosphatic chert sediments from the Krol Group (Terminal Neo-Proterozoic ~ 590 -543 mya) and Tal Group (Early Cambian ~ 540 mya) from the Lesser Himalayan sequences exposed in the Kamlidhar syncline north west of Mussorie. These they interpret as metazoan (multicellular animals) eggs and embryos. The findings are significant because they are some of the earlier known examples of body fossils of animals and will add to our understanding of the timing and nature of early animal evolution.

The Krol Group and the succeeding Tal Group represents sedimentation taking place in shallow to mid shelf environments along a passive continental margin that would in the future after Gondwanaland split up become the northern edge of the Indian continent facing the Tethys ocean.

The stratigraphic sequence is depicted in the image below with the position of the reported metazoan remains marked in red. 

Modified from:  Jiang et al 2003

The Krol Group has been interpreted as representing an evolving carbonate platform that shows a change from an early sloping ramp style geometry to a rimmed shelf to an open flat shelf profile over the course of tens of millions of years. This platform was north north-west facing i.e. the shoreline was to the south and the open deep ocean towards the north. Only the facies representing the shallower environments have been preserved in the study area. The deeper water equivalents are likely to be found in the High Himalayas in what are called the Tethyan Sequence exposed at great heights. The reported embryos are preserved in phosphatic chert lenticular bodies in a sandstone from the lowermost unit of the Krol sedimentary sequence. Younger units also contain evidence of multicellular animal life in the form of Ediacaran biota and sponge spicules.

The Tal Group represents more restricted conditions with algal buildup and lagoonal facies with deposits of phosphatic limestone, black shale and fine sandstone. From the sediments, phosphatized globular to sub-oval metazoan eggs with distinctively ornamented covering and polar lobe forming embryos have been found. They are associated with Small Shelly Fossils, a name given to a diverse array of fossils forms which are probably the dis-articulated remains of organisms like sponges, brachiopods, echinoderms, significant because they represent one of the earliest examples of metazoan biomineralization i.e. the ability to secrete hard skeletons from calcium carbonate.

The picture below from the Krol Group sediments shows a CT scan of the metazoan embryos at a two cell division stage. These have been interpreted as blastomeres representing the blastula stage embryos of animals.

Source: Sabhyasachi Shome et al -2014

And here are some more pictures of interpreted metazoans embryos from an earlier study of the Krol Group.

Source: R. Babu et al 2013 - Open Access- Description - a, Embryo showing cytoplasm, arrow showing air chamber;  b, Embryo showing developmental stage comparable to gastrula, arrow showing multicelled structure; c, Lower enlarged part of (b) (embryo), arrow showing two-layered wall (epidermis and endodermis); d, Embryo, arrow showing cleavages of blastula stage infilling homogenous organic matter (? proteineous in nature); e, Embryo showing cleavages; f, Upper enlarged part of (b) showing multicelled structure;


Some time back a friend asked me whether there is any chance of finding a Burgess Shale like Cambrian fossil bonanza in India. The Burgess Shale fossil locality in the Canadian Rocky Mountains is a Lagerstatte.. which means it represents an event of sudden entombment of the animal and/or plant life. This may be due to a submarine mud and silt flows burying the animal and plant communities in soft sediment leading to a snapshot of life at that particular moment. Rapid burial prevents degradation on the sea floor of organic remains. This means that even details of soft tissue along with hard parts are preserved as impressions on sediment. 

My answer to the question was that in Peninsular India sedimentation stopped by terminal Neo-Proterozoic. There were no Cambrian basins. But along the northern margin of proto-India in a basin which in the future would be deformed and uplifted to become the Himalayas, sedimentation continued in the Paleozoic. Which means Cambrian sediments are present, although I remarked they may be metamorphosed and destroyed. That is not the case however. The Krol and Tal Group do contain a Neo-Proterozoic to Early Cambrian fossil record with Ediacaran biota, sponge spicules and small shelly fossils indicating presence of metazoans. Their deeper water equivalents may be found in the High Himalayas! So, there is always a change of a spectacular fossil find either in or near more familiar places like Mussorie or Nainital where the Krol and Tal Groups are exposed or along the frigid heights of the Himalayan snow giants -for explorers brave enough to venture there.

Are Himalayan Glaciers Retreating?

Open Access in Current Science- A remote sensing survey of 2018 glaciers across the Himalayan arc for the time period 2001 -2010 was carried out. Change in snout position was compared. The majority of glaciers over the last ten years show stable snout positions. About 12% show retreat and only 0.9% show advancement. Himalayan glaciers are retreating though. Studies that cover larger time periods have shown that studied glaciers have been in retreat over all of the last century with the largest retreats from the mid 1970's to the late 1990's. Glaciers have been naturally shrinking since the last Ice Age ended with few reversals such as the younger Dryas and the Little Ice Age, but the past 100 years or so are of interest to us due to the impact of anthropogenic global warming.

Glacial retreat may have slowed down in the last decade and no doubt given the complex response of ice masses to their situation in a particular topographic setting and temperature changes such variations in rates of change of glacier decay will continue as the earth warms. Besides, as other water experts have pointed out , the big problem with interpreting the true significance of Himalayan glacier behavior is the lack of crucial baseline data for a) the amount of snowfall in the various Himalayan glacial source areas and b) much of the reporting of changes in glaciers present area changes and not changes in volume. The volume of ice corresponds to the volume of water held, so any assessment of damage to north Indian river supply must study volume change of ice as glacial melt contributes substantially to Himalayan river water flow. Furthermore, such data if it does exist and that collected in the future must be made public to be examined by as many experts as needed and not kept secret as has been the case with Himalayan river water data in the past. So, a lot more work in terms of basic data gathering needs to be done. 

In any case such larger scale studies are useful pointers to regional trends and for pinpointing areas deserving more detailed studies.

Abstract:

The Himalayan mountain system to the north of the Indian land mass with arcuate strike of NW–SE for about 2400 km holds one of the largest concentration of glaciers outside the polar regions in its high-altitude regions. Perennial snow and ice-melt from these frozen reservoirs is used in catchments and alluvial plains of the three major Himalayan river systems, i.e. the Indus, Ganga and Brahmaputra for irrigation, hydropower generation, production of bio-resources and fulfilling the domestic water demand. Also, variations in the extent of these glaciers are understood to be a sensitive indicator of climatic variations of the earth system and might have implications on the availability of water resources in the river systems. Therefore, mapping and monitoring of these fresh  water resources is require d for the planning of water resources and understanding the impact of climatic variations. Thus a study has been carried out to find the change in the extent of Himalayan glaciers during the last decade using IRS LISS III images of 2000 /01/02 and 2010/11. Two thousand and eighteen glaciers representing climatically diverse terrains in the Him a-laya were mapped and monitored. It includes glaciers of Karakoram, Himachal, Zanskar, Uttarakhand, Nepal and Sikkim regions. Among these, 1752 glaciers (86.8%) were observed having stable fronts (no change in the snout position and area of ablation zone), 248 (12.3%) exhibited retreat and 18 (0.9%) of them exhibited advancement of snout. The net loss in 10,250.68 sq km area of the 2018 glaciers put together was found to be 20.94 sq km or 0.2% (2.5 % of 20.94 sq km).

What Ails Indian Science

A strongly worded article by Mathai Joseph and Andrew Robinson in Nature points the finger at the bureaucratic stranglehold over Indian research institutes.

Some snippets...

The basic problem is that Indian science has for too long been hamstrung by a bureaucratic mentality that values administrative power over scientific achievement. And, to preserve local control, research is still done mostly by small teams working in isolation rather than through collaboration — a key generator of impact.

..Nearly 60% of India's science budget2 is now spent on the CSIR, scientific departments and the Defence Research and Development Organisation (DRDO) — an enormous and impenetrable empire set up in 1958. None of these national institutions has stimulated scientific excellence..

..The problems at the national level are mirrored in institutions. First, scientists are promoted on the basis of years of service, rather than achievement, and once at the top they stay until retirement age; long after, in some cases.

.. limited foreign travel and no travel support for research students, ruling out regular participation in leading conferences and research gatherings.

..the movement of researchers from one institution to another is discouraged, because administrators prefer senior positions to be filled by internal promotion rather than lateral hiring.

and 4 steps for change-

a) empowered funding agency
b) rotation of institutional role and responsibility
c) trans-institute groups (collaboration)
d) more money for State Universities that produce most of the country's PhD's.

..also worth reading is an older  article by Gautam Desiraju which takes a more detailed look on the current state of Indian science education and research.
 
..

Natural Selection And Punctuated Equilibrium

A reader asks-

I am still curious as to the mechanism and speed with which evolution by natural selection itself happened, like was it "punctuated equilibrium" or was it a slow and steady (continuous) mode of evolution, or was it a combination of the two, or some altogether third process. Not many programs discuss this unfortunately..

I left a short answer in a comment. Some additional thoughts:

Well.. Natural Selection and Punctuated Equilibrium are not directly connected with each other. Natural selection along with random genetic drift are mechanisms of evolution. Populations change in their genetic character and morphology due to natural selection or random genetic drift or a combination of the two. Punctuated equilibrium on the other hand refers to the tempo and pattern of morphological change seen in the fossil record and its significance. As was originally proposed by Eldridge and Gould it said that morphological change is concentrated in short bursts during cladogenesis i.e. when a new species buds off from an ancestral species. This change in morphology can be driven via natural selection or drift. So Punctuated Equilibrium says nothing about the primacy of any particular mechanism of evolution. Rather the emphasis is on the observed long periods of statis or little directional change in morphology in a lineage interrupted by geologically rapid bursts of change interpreted to be coupled to cladogenesis.

Gould later retracted somewhat from this position. He accepted the explanation for the pattern of Punctuated Equilibrium put forth by evolutionary biologist Douglas Futuyama which was that change could occur at any time during the life of a species but it is only when a small population gets reproductively isolated from its parent population i.e when the two populations stop exchanging genes that any directional change may get fixed or become permanent enough to show up in the fossil record.

Then there are examples of lineages changing in a slow and steady fashion too.. so can't generalize.. Nature has examples of both.

Regarding why programs don't cover this-its true that television programs have to my knowledge not covered this topic. My sense is programs on evolution and fossils stick to popular topics like the discovery of fossils of recognizable creatures like dinosaurs, the first tetrapods, proto-whales or on dramatic events in the history of life such as mass extinctions. A debate that uses detailed morphometric analysis of creatures like trilobites and foraminifers to reveal the pace of evolution (two organisms used extensively to test for patterns of punctuated equilibrium due to their abundance) may be thought of as too arcane to make for great television.

Having said that punctuated equilibrium got its fair share of attention in the print media and mostly for the wrong reasons for it was widely misinterpreted by the media as some kind of alternative to conventional evolution. The biggest mistakes made were in thinking that punctuated equilibrium means that new species form due to large morphological changes that occur suddenly. The primary authors Eldridge and Gould never advocated this, but the garbled version promoted in popular press made it seem so and large changes meant that some unknown genetic mechanism (macromutations?) may be at work. In reality, some of the demonstrated cases of punctuated equilibrium from trilobites showed that the new species differed only slightly from the ancestral species, nothing that could not be explained by well understood processes in an evolving population. So, an interesting theory that sought to explain patterns of appearances of new species in the fossil record as an example of allopatric speciation and migration became sensationalized as an alternative to "Darwin's theory" of evolution.

Creationists loved it,  palaeontologists banged their heads in frustration and much of the reading public have been confused ever since.

 

Neil deGrasse Tyson's Cosmos On Evolution

This past Sunday in India the second episode of Neil deGrasse Tyson's Cosmos was broadcast on National Geographic. The title was "What Molecules Can Do" and it was all about the evolution of life on earth. I quite enjoyed it. .. Just a couple of quibbles.

Dog evolution was showcased as an example of artificial selection which then Dr. Tyson used to argue for the efficacy of natural selection. It was depicted in cartoon form and the dog cartoons though showed quite a modern looking dog barking and scaring a wolf away from a campsite. This was meant to show the very early relationship  between dogs and humans. Early dogs wouldn't have looked as depicted in that frame. Its hard to point to modern dog breeds and find an analogue for the earliest dogs because they have changed so much and so late in their history. Still, a more smaller version of a wolf with a stubbier face would have been a best representative of early dogs, and not the hairier house pet looking one.

Later in the show Dr. Tyson wanting to emphasize that evolution is true says that the the "theory of evolution is a fact". That is a little confusing.  Evolution is a fact. Life has changed over the past 4 billion years and the theory of evolution is a theory that attempts to explain how it happened. There are many theories of evolution. Some like Lamarck's theory rely on organisms responding to environmental stimuli and the inheritance of acquired characters to explain change. Creationists in their garb of Intelligent Design have faith in an unknown intelligence guiding natural processes. Modern evolutionary theory that adds on to Darwin's and Wallace's insights is the most successful one.

Dating The Indian Proterozoic Sediments Using Diagenetic Glauconite

Geological radioactive clocks which rely on the known rate of decay of radioactive elements start ticking when these radioactive elements gets trapped in growing minerals and the mineral stops exchanging elements with its surroundings. This commonly occurs in minerals crystallizing out of magma or lava  or when a mineral recrystallizes during metamorphism. A radioactive clock from a mineral in an igneous rock tells us the date of the solidification of the magma or lava while a radioactive clock from a metamorphic rock may time the thermal event during which the host igneous or metamorphic rock recrystallized.

What about directly dating sedimentary rocks using radioactive clocks? Rocks like sandstones for example are made up of pieces of eroded igneous or metamorphic or sedimentary rocks. They may contain minerals like zircon that contain uranium or feldspars that contain radiogenic potassium, but dating these sedimentary particles  means finding out  the age of the source rocks and not neccessarily the timing of deposition of sediment.

One can indirectly date sedimentary rocks using radioactive clocks based on their geological relationship with associated igneous rocks. For example; 1) a sandstone sequence may unconformably overlie a granite. The age of the granite tells us that the sandstone sequence is younger than a particular date. 2) a sedimentary sequence may be intruded by an igneous body. The age of that igneous body if established tells us that the sequence is older than a particular date and 3) a sedimentary sequence may be bounded by igneous bodies, example volcanic eruptions many deposit lava or ash at various intervals synchronous with sediment deposition. In this case, the dates if established tell us that sedimentation occurred between two particular dates.

Often though a fortuitous association with igneous rocks is absent or saying "younger than", or "older than" or "between" leaves tens of millions or even hundreds of millions of years unaccounted for. In a study published a few years ago in GSA Bulletin, James E. Conrad and colleagues use another approach to directly date when sedimentation occurred. Although sedimentary rocks like sandstones are mostly made up of eroded particles they also occasionally contain minerals that grow on the sea floor or a few cms below  the sediment water interface. Such new minerals that form during or just after sedimentation are called diagenetic or authigenic minerals. Glauconite is one such diagenetic mineral which grows on the sea floor. It is a iron potassium (K) silicate and the radiogenic K40 decays into Argon40. Using the ratio of Ar40 to non radiogenic Ar39, the age of glauconite formation and thus sediment deposition was established.

Indian Proterozoic basins are just beginning to get their chronology established more robustly and diagenetic glauconite which is present in many different Indian basins offers another tool besides associated igneous rocks to more firmly establish the timing of basin formation, sedimentation, sequence evolution and changes in ocean geochemical conditions (glauconite forms under reducing conditions on the sea floor) during Proterozoic times.

Abstract:

Ages of some key stratigraphic sequences in central Indian Proterozoic basins are based predominantly on lithostratigraphic relationships that have been constrained by only a few radioisotopic dates. To help improve age constraints, single grains of glauconitic minerals taken from sandstone and limestone in two Proterozoic sequences in the Pranhita-Godavari Valley and the Chattisgarh basin were analyzed by the 40Ar/39Ar incremental heating method. Analysis of the age spectra distinguishes between ages that are interpreted to reflect the time of glauconite formation, and anomalous ages that result from inherited argon or postcrystallization heating. The analyses indicate an age of 1686 ± 6 Ma for the Pandikunta Limestone and 1566 ± 6 Ma for the Ramgundam Sandstone, two units in the western belt of Proterozoic sequences in Pranhita-Godavari Valley. Glauconite from the Chanda Limestone, in the upper part of this sequence, contains inherited 40Ar but is interpreted to reflect an age of ca. 1200 Ma. Glauconite from the Somanpalli Group in the eastern belt of the Pranhita-Godavari Valley gives an age of 1620 ± 6 Ma. In the Chattisgarh basin, glauconite from two units gives disturbed ages that suggest a period of regional heating in the Chattisgarh basin at ca. 960–1000 Ma. These new ages indicate that these sequences are 200–400 m.y. older than previously recognized, which has important implications for geochemical studies of Mesoproterozoic ocean redox conditions in addition to providing important constraints on regional tectonics and lithostratigraphy.