Readings: Human Evolution, Ice Ages, Brains In Digital Age

Some interesting articles to read:

1) How did Homo sapiens evolve in Africa? Did one population branch off and evolve all the traits of 'modern humans' in isolation or were there several populations spread across the continent which at times evolved in isolation but periodically met and exchanged genes and cultural practices, resulting in a gradual coming together of the constellation of traits we see in us? Recent findings based on the fossil and tool record is pointing to the latter process.

The search for Eden: in pursuit of humanity’s origins by Robin McKie.

2) How do variations in the earth's orbit influence the growth and decline of glacial and interglacial periods? Excellent review article on the factors controlling climate change over the past 2.5 million years.

Tying celestial mechanics to Earth’s ice ages by Mark Maslin.

3) How is the human brain coping with the information deluge of our times?

Extract:

" Humans, of course, forage for data more voraciously than any other animal. And, like most foragers, we follow instinctive strategies for optimizing our search. Behavioral ecologists who study animals seeking nourishment have developed various models to predict their likely course of action. One of these, the marginal value theorem (MVT), applies to foragers in areas where food is found in patches, with resource-poor areas in between. The MVT can predict, for example, when a squirrel will quit gathering acorns in one tree and move on to the next, based on a formula assessing the costs and benefits of staying put — the number of nuts acquired per minute versus the time required for travel, and so on. Gazzaley sees the digital landscape as a similar environment, in which the patches are sources of information — a website, a smartphone, an email program. He believes an MVT-like formula may govern our online foraging: Each data patch provides diminishing returns over time as we use up information available there, or as we start to worry that better data might be available elsewhere.

The call of the next data patch may keep us hopping from Facebook to Twitter to Google to YouTube; it can also interfere with the fulfillment of goals — meeting a work deadline, paying attention in class, connecting face-to-face with a loved one."

There is some sensible advice at the end on how to build healthier habits and manage our dependencies on technology.

How Our Ancient Brains Are Coping in the Age of Digital Distraction by Kenneth Miller.

Books: Tree Story, Rivers of Power

A friend pointed out these two books.

1) Tree Story: The History of the World Written in Rings by Valerie Trouet.

Review: "Trouet, a leading tree-ring scientist, takes us out into the field, from remote African villages to radioactive Russian forests, offering readers an insider's look at tree-ring research, a discipline formally known as dendrochronology. Tracing her own professional journey while exploring dendrochronology's history and applications, Trouet describes the basics of how tell-tale tree cores are collected and dated with ring-by-ring precision, explaining the unexpected and momentous insights we've gained from the resulting samples"...



2) Rivers of Power: How a Natural Force Raised Kingdoms, Destroyed Civilizations, and Shapes Our World by Laurence C. Smith

.."From ancient Egypt to our growing contemporary metropolises, Rivers of Power reveals why rivers matter so profoundly to human civilization, and how they continue to be indispensable to our societies and wellbeing"...

Two other books on rivers that I would recommend are Unruly Waters by Sunil Amrith and The Water Kingdom by Philip Ball.

I also want to read The Unquiet River: A Biography of the Brahmaputra by Arupjyoti Saikia. Hoping to get to it soon.


Happy Reading!

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.