1) The Promise and Risks of Deep-Sea Mining: In late 1988 I visited the National Institute of Oceanography in Goa for a job interview. The buzz in the marine geology labs was about the discovery of manganese nodules on the deep sea bed of the Indian continental shelf. At that time, exploration had just started and the technology was not advanced enough to mine these lumps which contained, besides manganese, other metals like cobalt, nickel, and copper. The nodule deposits were being looked at as a future resource.
That day is upon us. Many countries have expressed an interest in mining the deep-sea bed for metals required for the transition away from fossil fuels. Metals concentration of Mn, Co, Ni, and Cu also occurs around hydrothermal vents. Not much is known about the ecology and biodiversity of these remote sites. Most experts feel that mining will result in extensive damage to the sea floor ecosystems and to life in the surrounding water column.
Daisy Chung, Ernest Scheyder, and Clare Trainor describe what is at stake in this beautifully illustrated article published by Reuters.
2) Indus Valley farming started later than thought, radiocarbon study shows: Mehrgarh, in Balochistan, Pakistan, was thought to be South Asia's oldest farming settlement going back to around 8000 B.C. New carbon dating of grains using a more robust dating method called Accelerator Mass Spectrometry has revised the date of earliest occupation to around 5200 B.C. Subhra Priyadarshini writes about the implications of this new date with regards to the origins and spread of farming in South Asia and cultural linkages of Mehrgarh to the Indus Civilization.
3) Water Towers of the Indus Basin: Last month's heinous terrorist attack in Pahalgam, Jammu and Kashmir, India, has refocused attention on the Indus Water Treaty between India and Pakistan and the many hydropower projects that India is planning on the Indus and the Chenab rivers. These rivers provide water security to vast areas of India and Pakistan.
Despite the importance of these rivers to local livelihoods, hydropower projects are being built without due consideration being given to the impact dam construction and climate change will have on the Himalaya ecosystem..
Parineeta Dandekar (story), Abhay Kanvinde (photos), and Michelle Hooper (story map) meticulously document the completed and planned hydropower projects along the Chenab river and point to the lapses in science and environmental governance that have taken place during the project planning process.
Jyotirao Phule (1827-1890) was a social reformer from Maharashtra who worked for the emancipation of the lower castes and for improving the lives of peasant agriculturists. In Shetkaryacha Asud (The Cultivator's Whipcord), written in 1883, he describes the plight of poor farmers and offers some advice on improving yield through land management practices.
An excerpt-
The essence of leaf, grass, flower, dead insects and animals, is washed away by summer rain, therefore our industrious government should, as and when convenient, use the white and black soldiers and the extra manpower in the police department to construct small dams and bunds in such a way that this water should seep into the ground, and only later go and meet streams and rivers. This would make the land very fertile , and the soldiers in general, having got to working in [the] open air, will also improve their health and become strong.
.....Therefore the government should maintain these bunds in good condition, especially the backwaters. The government should conduct surveys of all the lands in its territory, employing water specialists, and wherever it is found that there is enough water to be drawn from more than one source, these places should be clearly marked in the maps of the towns, and the government should give some awards to farmers who dig wells without its assistance. Also the government should allow the farmer to collect all the silt and other things extracted from rivers and lakes, as in the older times, and it should also return all the cow pastures to the villages, which it has included in its 'forest'.
Phule covers many of the interventions that are recommended by watershed management specialists today. The last line of the passage I have quoted is telling. Preventing villagers from using what was traditionally considered 'village commons' has always been contested by the people. Phule also called for the destruction of the "oppressive Forest Department". The conflict between agriculturists, forest dwellers, pastoralists, and the forest department continues to this day.
This essay, translated from Marathi to English by Aniket Jaaware, has been republished in Makers of Modern India, a compilation of essays written through the 19th and 20th century by influential Indian political activists and social reformers. The collection is edited and introduced by historian Ramachandra Guha.
Some interesting geology rich readings from the past few weeks:
1) Ichnology is a branch of palaeontology that studies the traces made by organisms in soft sediment. These could be tracks and trails as animals move around on a substrate, or burrows constructed as escape structures or as dwellings, or bite marks on shells and bones. All these are indicative of behavior, which otherwise would be hard to discern from just the fossilized remains of body parts. Science writer Jeanne Timmons has written this lovely article on Ichnofossils and what they tell us about past ecology and animal behavior.
2) The earth has seen over its long geological history episodes of continents coming together to form a supercontinent, then breaking up and drifting apart forwhat seems an eternity, but eventually coalescing to form another giant landmass. When did this supercontinent cycle begin on earth. What are the forces that initiated and subsequently has maintained this mode of surface reconfiguration, and what are its consequences on tectonics, and the physical and chemical evolution of earth. A great review article by Ross N. Mitchell and colleagues.
3) The rivers that sustained the Bronze Age Harappan Civilization have been the subject of lively research in recent years. Ajit Singh and colleagues have worked on the Markanda river catchment in the Sub-Himalaya dun region. Markanda joins the Ghaggar-Hakra river flowing through present day Harayana, Punjab and Rajasthan. They find that during the Mature Harappan Period (2600 B.C. to 1900 B.C.), large floods in the Himalaya foothill rivers sustained flow in downstream reaches, making agricultural viable, even as northwestern parts of India experienced a reduction in summer monsoon strength.
You didn't think I would stop at just three books, did you? More were delivered few days back.
1) Was the transition from a hunter gatherer lifestyle to agriculture a prerequisite for the formation of complex societies? James C.Scott explores this link between sedentism, domestication and state formation. The Sumerian Ur city state that formed around 3800 B.C is one example of this. New archaeological discoveries are hinting at complex societies of antiquity greater that the agriculture linked complexes that came up in the fertile crescent. Sites like Gobekli Tepe in Turkey may make us reexamine our assumptions regarding the causes and timing of the formation of early states. Besides this book, I will recommend this essay by Samo Burja - Why Civilization is older than we thought.
2) In the past year, I read four fine books on Indian history covering the time span from the 1000's to about the 1750's. India in the Persianate Age 1000-1765 and A Social History of the Deccan, 1300-1761: Eight Indian Lives, both by Richard M. Eaton. The Emergence of the Delhi Sultanate by Sunil Kumar who sadly passed away recently. And the fourth was The Mughal State 1526-1750. This is a collection of essays collated by Muzaffar Alam and Sanjay Subrahmanyam with a long introductory critical essay on Mughal historiography by the two editors. I thought it was time for me to explore the few centuries preceding the arrival of Central Asian Turkic invaders. The Making of Early Medieval India and The Early Medieval in South India look like good introductions to this time period.
1) This came highly recommended from science Twitter. Peter Godfrey-Smith has surveyed a wide section of the animal kingdom and writes about the evolution of sensory experiences in different species. Sponges, corals, worms and octopus all manipulate the environments in specific ways. Disparate evolutionary pathways to be sure, but they all inform us about the origins of our mental capacities.
2) I had a brief introduction to this book over a chickoo milkshake when the author M. Rajshekhar had visited Pune couple of years ago. He has spent several years traveling across India, surveying both big cities and the rural regions. His Ear to the Ground project resulted in scores of articles on India's everyday economy and the general failure of governance in this country. Its good to see some of his work distilled into this book.
3) Live History India has a really good interview with Peggy Mohan about her new book on India's language history. This is always a fascinating topic, as it tells us so much about population history, their origins, migrations, and intermingling. There is a section on Marathi too, and I'm looking forward to learning about that.
1) What was the impact of Deccan Volcanism on the end-Cretaceous mass extinction? Improved dating of the timing of volcanism shows that volcanism spanned the mass extinction. But what changes occurred to marine environments because of the outgassing wasn't well documented. A new study uses the oxygen isotope ratios in foraminifera shells to estimate ocean temperature changes before and after the mass extinction. The finding is that the oceans warmed well before the extinction but cooled back again. The warming event doesn't appear to correlate with marine extinctions. Rather the mass extinction coincides with evidence for a meteorite impact.
Here is a figure from the paper on the estimated temperature changes collated using a variety of proxies:
2) Anthropological geneticist Jennifer Raff has pieced together the genomic story of the peopling of the American continents in this really insightful article. Do read it!
3) And next, onwards to a bit of Indian history. A very interesting conversation between Live History India editor Mini Menon and author Yashaswini Chandra on Ms. Chandra's new book, The Tale of the Horse: A History of India on Horseback. Fascinating story of the horse trade from Central Asia into India and its assimilation as a war animal and into Indian society.
Some interesting readings over the past few weeks:
1) Myanmar Geology- Oblique convergence, where plates converge or collide at an angle, has produced some stunning geological features in Myanmar. Lon Abbot and Terri Cook sail down the Irrawaddy River describing vestiges of volcanic arcs, strike slip faults, en echelon sedimentary basins, and fold mountains, with a fair bit thrown in about the architecture and cultural history of the country.
2) Genetics And Human Evolution- Razib Khan compiles a nice list of the many aspects of human evolution and especially Holocene population history that has been brought out by recent work in genomics and ancient DNA.
3) Indian Archaeology- A sort of historiography of the field of Indian archaeology from Colonial times to today. Dilip Menon writes about the push and pull of ideas of conquest, politics, and nationalism that influence Indian archaeology research and narratives.
Prof. Vipul Singh is with the Dept. of History, University of Delhi, and he writes in the acknowledgments section that environmental history as a formal subject of study in history departments had a late start in India. The focus of the book is the flat lands of Bihar with its annual floods and shifting river channels and how Mughal and later British land use policies transformed the people's relationship with the river system. Looks like a very meaty book with plenty of Notes, Maps and a long Reference section. Will be sharing interesting snippets as I read along.
As one blurb says... "Perfect to pop into your pocket for spare moments". A fine introduction by Jamie Woodward. The recognition that the earth has passed through several glacial and interglacial phases is really a triumph of field geology. Thick sedimentary deposits in Europe and N. America were recognized as being left behind by advancing ice sheets. The stellar role played by geologists in the mid-late 1800's and their debates grounded within the prevailing schools of catastrophism versus uniformitarianism is highlighted. And there are good succinct sections on the many modern theoretical advances in climate science and the techniques that geologists and climate scientists bring to bear upon understanding the mode and tempo of climate change.
1) Neeraj Wagholikar, Parineeta Dandekar and Himanshu Thakkar weigh in on the dam building epidemic that is afflicting India. These three experts cover issues of environmental governance, destruction of fisheries and livelihoods, and a perspective on their irrigation potential and economic logic.
The deep political drive to push through permissions to build dams is best highlighted by an example of a malign recommendation in a report of the Parliamentary Standing Committee on energy published in January 2019. It seems to view in favor Himachal Pradesh's suggestion to the committee to help declare large hydropower projects as linear projects, thus enabling them to bypass Gram Sabha consent. The statement reads, “If it is done, then, to a large extent, the problem of FRA, which the Secretary also mentioned, will get resolved because the stringent provisions of FRA will get diluted. It is not our purpose to subvert them. Our only purpose is to get them more liberalised.”
FRA is the Forest Rights Act which gives local forest dwellers a say in the site selection of infrastructure projects.
2) Geology fans! I highly recommend Rice University Professor Cin-Ty Lee's YouTube Channel. He has a very informative collection of short videos on rocks and minerals and geologic processes.
Here is one of my favorites.. Isostacy and what controls the elevation of mountains?
Email subscribers who can't see the embedded video, can view it here - Elevation of Mountains.
3) Like Sugar in Milk.. was the memorable assurance given by the Zoroastrian refugees to the King of Gujarat. We will assimilate in Indian society. And they have in many ways, while maintaining a distinct identity.
What does genetics tell us? Fine post by Razib Khan.
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"...
.."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.
Is this sandstone slab in its original geological orientation (as when the sedimentary layers were deposited) or is it upside down? I'll answer this a little later, but first some background.
I recently visited the Chalukya style temples and rock cut monuments at Aihole, Pattadakal and Badami (6th -8th CE) in northern Karnataka and noticed some great sedimentary structures in the building stones. The term sedimentary structures refers to the shape and form sedimentary layers get sculpted into by the action of waves, currents, tides and wind during deposition of the sediment. The size of the deposited sedimentary particles and the orientation of layers are a reflection of both the vigor of the currents and waves and the direction of flow of water or wind.
These monuments are made up of Neoproterozoic age (900-800 million year old) sandstones. Geologists have recognized using detailed sedimentological analysis that the sandstones formed mostly in a large braided river system that flowed in a northwesterly direction.
Between roughly 1800 -800 million years ago, over the course of a billion years, the Indian continental crust sagged due to various tectonic forces to form several long lasting sedimentary basins. The Kaladgi Basin in which the Badami area sandstones were deposited is one such basin. The paleogeographic reconstruction below shows the position of the Indian continent at about one billion years ago and the location of the various sedimentary basins within it.
Much of this deposition took place in inland or epeiric seas that flooded the Indian continent. During intervals of sea level fall, rivers carved valleys and deposited coarse sediment. The Badami Cave sandstones are river deposits of the Kaladgi Basin. The stratigraphic column shows various sedimentary deposits of the Kaladgi Basin and their inferred environments of deposition.
The Badami braided river system was receiving sediment eroded from Archean age (>2.5 billion year old) rocks situated SE of the basin. These were granites, granodiorites, and low to medium grade metamorphic rocks of the Dharwar craton (a large block of stable old continental crust).
Land plants did not exist then. Weathered debris was moved quickly by surface flow into streams. Large sediment load, moving by traction i.e. by rolling and sliding on the stream bed, repeatedly choked the channels, forcing bifurcation of streams and formation of braids. Very broad braided rivers formed since there were no plants to stabilize banks. The Badami sandstones (Cave Temple Formation) are technically known as arenites. This term indicates that the rock is made up of mostly coarse sand with very little finer sized mud. Accumulation of mostly coarser sand size and pebbly particles reflects a locale of repeated high discharges and vigorous currents which winnowed away the finer sized mud. The braided river shown below as an example is from the Canterbury Plains of New Zealand.
As river channels episodically migrated sideways and the basin floor subsided to accommodate more sediment, channel deposits and adjacent sand bars got stacked to form thick 'multi-story' sandstones. Each bed tells a story of a discrete depositional episode.
The arrangement of sand layers within each bed tells us about the subenvironments in which it formed and the energy and direction of water flow during deposition. I came across many types of these internal structures. I recognized tabular cross beds, trough cross beds, planar lamination and rippled beds. Water (or wind) can move & shape sand into piles or waves. Sand grains roll along the direction of flow, then avalanche down the steeper side (lee side) of the wave forming a layer inclined (cross) to the orientation of the main sand body. Successive avalanches form a set of cross beds. The graphic shows the formation of a set of cross beds.
Here is an example of cross beds from near the town of Badami.
And this one is from a building stone from Pattadakal temple.
Such cross beds were built by sediment avalanching on the lee side of migrating sand bars during high flow.
This picture show trough cross bedding from near the Badami cave complex. These represent the internal structure of migrating sinuous sand dunes on a channel floor.
See this elegant explanation by Dawn Sumner, a sedimentologist at the University of California at Davis, of how trough cross beds form.
Email subscribers who may not be able to see the embedded video, click on this link: Trough Cross Bedding Video.
And here is a beautiful example of trough cross bedding found in a Pattadakal temple building stone.
This is planar lamination on a slab at Pattadakal. The bed is constructed of parallel layers of coarse sand. It is interpreted to have been deposited in a high flow regime from sheets of water flowing over mid channel sand bars.
Ripples on a slab at Pattadakal. This is a rare preservation of a bedding surface showing rippled sand. Erosion usually cuts off the wavy upper part. These ripples indicate migration of small sand waves in a quieter flow regime on the channel floor.
Remember, cross beds are the inclined layers that form on the lee side of a ripple or wave or dune. Here are small cross sets on the floor of Aihole rock cut temple! These represent the cross beds formed by migration of small ripples. The ripples themselves have been eroded away. Arrows indicate the direction of water flow and cross bed accretion as ripples migrated.
Okay, let's go back to my first question. Is the slab I showed in the picture geologically upside down?
Yes it is. But how to tell?
As sand avalanches down the lee slope it forms a tail at the toe of the slope resulting in cross beds which become tangential to the floor. In picture the cross beds are tangential towards the top of slab i.e. that is actually the base.
Lets see at how the cross bed contact with the top and bottom bedding plane looks in an outcrop. Here is the original depositional orientation of cross beds manifest in this outcrop near Badami caves. They show a tail or tangential contact of the cross beds with the base. Since top of cross beds are not usually preserved they show a high angle contact truncated by upper bedding plane.
This slab is upside down too! Notice again the tangential contact of the cross beds (white arrow) is towards the top, which means that must have been the base. Yellow arrow points to high angle contact with the upper bedding surface.
Towards the top of the exposed section of sandstone around Badami I came across some truly impressive examples of cross bedding. These particular exposures were on the crags opposite the four main Badami temples. There is a narrow passage past the archaeological museum and a short climb to the top. Take a look at these beauties!
These large cross beds reminded me of the inclined beds of wind blown sand dunes. Is it possible that abandoned sand bars were sculpted by wind in to big dunes? Or does this upper level sandstone represent, as a recent study suggests, the beginning of a marine incursion in to the basin? In this scenario, deposition of sand took place in high-energy shallow waters near the shore. These cross beds represent large migrating sand waves which were eventually shaped in to beach ridges and tidal bars. The outcrops and building stones of these monuments mostly record the processes within the Badami braided paleo-river. 900 million yrs ago a complex of channels and bars, quieter pools and rippled sand beds existed where these temples stand today.
Do visit Aihole, Pattadakal and Badami and gaze at its splendid architecture and sculptures. But spare some time to appreciate the magnificent record of our natural history that these monuments preserve.
Quiz- Is this slab upside down or in its true depositional orientation? 😉
Did a perennial glacial fed river flow through the Indus Civilization region of what is now Haryana and Rajasthan? Previous work on the fluvial history of this region had indicated that a distributary of the glacially sourced Sutlej was flowing through a network of paleo-channels buried under the river now known as the Ghaggar until around 8,000 years ago. The Sutlej distributary system then died out, turning that river course into a smaller monsoon fed channel system.
For a more detailed history of research on this topic you can follow this link - Ghaggar /Saraswati Posts.
Recently, in November 2019, Anirban Chatterjee and colleagues published new data on deposits of grey sand in the subsurface of the Ghaggar channel and adjacent floodplains. The youngest of these deposits are 4, 500 years old. Geochemical fingerprinting points to High Himalayan granites and gneisses as their source. This likely extends the glacial phase of the Ghaggar to more recent times, until about the beginning of the urbanization of the Indus Valley Civilization (IVC).
The legendary river Saraswati of Indian mythology has often been hypothesized to be an ancient perennial channel of the seasonal river Ghaggar that flowed through the heartland of the Bronze Age Harappan civilization in north-western India. Despite the discovery of abundant settlements along a major paleo-channel of the Ghaggar, many believed that the Harappans depended solely on monsoonal rains, because no proof existed for the river’s uninterrupted flow during the zenith of the civilization. Here, we present unequivocal evidence for the Ghaggar’s perennial past by studying temporal changes of sediment provenance along a 300 km stretch of the river basin. This is achieved using 40Ar/39Ar ages of detrital muscovite and Sr-Nd isotopic ratios of siliciclastic sediment in fluvial sequences, dated by radiocarbon and luminescence methods. We establish that during 80-20 ka and 9-4.5 ka the river was perennial and was receiving sediments from the Higher and Lesser Himalayas. The latter phase can be attributed to the reactivation of the river by the distributaries of the Sutlej. This revived perennial condition of the Ghaggar, which can be correlated with the Saraswati, likely facilitated development of the early Harappan settlements along its banks. The timing of the eventual decline of the river, which led to the collapse of the civilization, approximately coincides with the commencement of the Meghalayan Stage.
The geological work looks to be sound. The data on sediment fingerprinting overlaps with what we know about High Himalayan geochemical signatures and present day Sutlej sand composition.
I do want to comment on another sentence from the abstract (emphasis mine)-
"This revived perennial condition of the Ghaggar, which can be correlated with the Saraswati, likely facilitated development of the early Harappan settlements along its banks"
Saraswati is the name given to this river by the Vedic people. Correlation of the river's perennial phase between 9,000-4,500 years ago with Saraswati is valid only if you can demonstrate that the Vedic people were inhabitants of this region from before 4,500 yrs ago. Geological studies cannot establish this. A combination of archeology, linguistics (cracking the Indus script would be nice!) and genetics will eventually answer that. The other scenario is that the Vedic people could have migrated into this region much later and began venerating a smaller monsoonal Ghaggar as Saraswati. Work by Liviu Giosan and colleagues suggests that stronger monsoons over the Siwaliks sustained sufficient flow in the old channels of the Ghaggar until the late IVC period (~1800-1600 B.C).
When did this river come to be called the Saraswati is still an open question.
Two recent genetics papers using ancient DNA recovered from the IVC site of Rakhigarhi and from Central Asia argue that people from the Pontic-Caspian steppes migrated into South Asia between 2000 -1500 B.C. bringing with them the Indo-Iranian branch of the Indo-European language family. These would presumably be the Vedic people.
These two recently published papers are worth reading.
The first one reviews settlement patterns, water availability, agricultural strategies and craft production in urban and rural Indus settlements. It draws inferences on the type of power structures and hierarchies that may have prevailed within cities and villages and between different regions. And there is the perennial question on the link between climate change, water stress and the decline of urban sphere of the Indus civilization. There were different response from the urban and rural spheres to environmental stress, with the more flexible and adaptable rural lifeways showing more resilience and sustainability.
"Petrie et al. (2017; Petrie 2017) have suggested that the weakening of the ISM around c. 2200–2100 bc meant that the climate in the subsequent period became ‘unpredictably unpredictable’. By this we meant that before and during the Indus urban phase, populations were familiar with ‘predictable unpredictable’ conditions and their farming strategies were tailored to make use of water supplied by combinations of rainfall, inundation, small-scale irrigation and/or lifted water (cf. Miller 2006). Populations in specific areas across the Indus zone might have been able to survive one, two, or even more years of drought, either through reliance on their own resources, or through support from other regions. However, when this range was exceeded, such as when populations were faced with protracted periods of drought, the local and medium-to-long range provisioning and support networks may not have been able to sustain the status quo. I have suggested that in such a situation, farmers may have had to engage in constant risk mitigation, thereby reducing opportunities to produce surpluses, and in such situations it is possible that living in large groups (i.e. urban centres) was not an option".
The Indus cultural sphere lasted a long time after its cities declined. In the graphic below the upper left and right panels show distribution of settlements during the urban phase with modern winter (left) and summer (right) rainfall contours overlain. The bottom panel shows the post urban settlement patterns. There are denser habitations nearer the Himalaya front in the post urban phase. This shift from Rajasthan, Cholistan and Haryana eastwards and closer to the Himalaya foothills followed more reliable monsoons in that region. Gujarat on the other hand wasn't depopulated as much suggesting regional differences in monsoon strength and varied water harvesting strategies. However, the urban center of Dholavira and nearby settlements were abandoned.
Even the decline of the cities was not a sudden event. Indus societies did not collapse due to any one catastrophic environmental change such as one big river changing course or a very rapid decline in monsoon. Urbanization was at a peak between 2600 B.C and 1900 B.C. But at Mohenjodaro for example, signs of abandonment and depopulation begin by 2200 B.C. On the other, Harappa continued to be occupied throughout the urban phase and well into the late Harappan Phase, although analysis of skeletons do suggest increasing physical stress.
The second paper by Danika Parikh and Cameron Petrie concentrates on bringing out the complexities and variation in rural lifeways and economies. Ceramic products from four Indus age villages in Haryana are analyzed and described and some interesting inferences drawn on urban rural (in)dependence and the socio-economic role of villages in the larger Indus sphere.
"The regional rural ceramic economy innorthwest India was clearly complex and shows a considerable degree of variation. Rural communities produced some ceramic forms similar to Classic Harappan forms, and others that were quite different, and they used some decorativemotifs that were common and others that we had previously not seen. This pattern of similar ceramic forms but different techniques and decoration is particularly interesting, given what we understand of how pottery production is learned. Pottery forming is often learned through ‘vertical transmission’, inter-generationally; shape and decorative motifs are more easily imitated and are often transmitted horizontally, or peer-to-peer (Knappett 2011, 106–107; see also Gosselain 2000). The use of different techniques to produce the same forms suggests that Classic Harappan and Haryana Harappan ceramicmaterial was not produced in the same workshops, and that these potters are unlikely to have been members of the same communities of practice".
The rural populations were not only engaged in agro-pastoralism. Villages had varied occupations such as functioning as workshops for specialized craft production and as factory sites making goods for larger towns and cities.
..continuing on the topic of environmental changes and Harappan Civilization. Gayatri Kathayat and colleagues have teased out an intra-decadal record of variability of Indian monsoons from a cave deposit in Uttarakhand. This they did by measuring the O18/O16 ratio in the mineral calcite (CaCO3) which grew incrementally to form a speleothem. The lighter isotope of oxygen is preferentially retained in the vapour phase. Less and more amounts of rainfall thus results in less or more amounts of O16 in rain and groundwater and eventually in the mineral calcite that precipitates from that groundwater. This is known as the amount effect. A chronology of speleothem growth was established using thorium 230 dating method.
The record for the past 5700 years is summarized in this figure. The time period of the growth and consolidation of urban Harappan society coincides with a period of accentuated monsoons.
The hydroclimate conditions during the evolution and subsequent decline of the IVC have remained a subject of debate (for example, 9, 14–19). On the basis of the Sahiya d18Orecord, the Early and Mature Phases occurred during a fairly wet/warm and climatically stable period. The Mature Phase began around an abrupt intensification of the ISM at ~4550 yr BP (Fig. 3) and sustained for nearly ~700 years to ~3850 yr BP, corresponding with the late portion of the mid-Holocene Climate Optimum, during which the ISM reached its maximum over the past 5700 years. It is plausible that the optimum (warm/wet) climate might have allowed the civilization to develop a farming system with large and reliant agricultural surpluses, which in turn supports the development of cities.
Previous studies have attributed societal collapses in the Middle East and in the Indus Valley to a climate event, the so-called “4.2 ka BP event” (or ca. ~4.2–3.9 ka BP event) (15–21, 42–45). The 4.2 ka BP event in the Sahiya d18O record manifests as an interval of declining ISM strength, marked by a relatively higher-amplitude d18O variability and a slow speleothem growth rate, rather than as a singular prominent abrupt event (Fig. 2). A lack of an abrupt change in our record around the time is consistentwith the idea that the 4.2 ka event did not influence the Deurbanization Phase (14) in contrast to the more severe societal impact it had on the Old Kingdom in Egypt and the Akkadian Empire in Mesopotamia (42–45).
Some commentators have already pointed out that this sample is well removed from the Harappan realm and we need to understand regional variation in monsoons before drawing any firm link between monsoon variability and Harappan civilization phases. In that context, let me put up another figure from a study of the Kotla Dahar lake sediments from Haryana. This site falls within the Harappan region. Yama Dixit and colleagues measured oxgyen isotopes of carbonate lake sediment as well as from gastropod (snail) shells. Take a look at the figure below.
The variation in oxygen isotope ratios is due to variation in intensity of evaporation. Greater evaporation during dry phases results in the lake water getting enriched in the heavier isotope (the lighter isotope goes into the vapor phase more readily). Sediment and shells precipitated from this water will therefore get enriched in the heavier isotope during dry phases. Their sampling is coarser than the Sahiya study. But, if you look at the time period from around 5000 BP to around 3800 BP, there is no clear persistent trend towards monsoon intensification (should show up as a centuries long shift towards more negative dO18 values since evaporation will be less during wet phases). A fine resolution local record is needed to fill in the details and explain this apparent contradiction.
Finally, I came across a talk by archaeologist Shereen Ratnagar on environmental changes, river history and the Harappan Civilization. She does not like the theory that climate change was responsible for the decline of the Harappan Civilization. Instead, she prefers a social sciences approach, arguing that factors like the over-extension of empire and social dynamics need to be taken into account. Well, I am not sure that these are mutually exclusive. Civilizations may be in a phase of political and social cohesiveness whereby they could prove resilient against environmental changes. In times where their capacity for collective action is weak for internal reasons of polity and demography, exogenous factors like climate change may trigger disruption and decline.
She spends a lot of time criticizing a study by Liviu Giosan and colleagues on the fluvial history of that region. That paper showed that during Harappan times there were no glacial rivers flowing in the region between Yamuna and the Indus. Ratnagar points out that there might have been tributaries of the Yamuna and overspill of the Sutlej that may have provided water to the channel of the Ghaggar river and so there was no severe water shortage. But Giosan's work has not claimed that! They too point out that higher rainfall in the Siwaliks would have kept the Ghaggar perennial through most of the urban Harappan phase. They find that sedimentation continued through the late Harappan phase as well. The study suggests that continued monsoon decline and drying resulted in migration away from the Ghaggar-Hakra belt. However, they don't argue for a direct link between abrupt climate change and civilization decline across the entire Harappan extent. Anyways, the talk is worth listening too, especially her analysis of the wonderful water management strategies at the Harappan age site of Dholavira in Kutch, Gujarat.
I am reading Philip Ball's excellent book The Water Kingdom: A Secret History Of China. It describes the epic problems of river flow management that China has grappled with over millennia. Enormous floods have always ravaged China. At the site of a large dam at Sanmenxia on the Yellow River is an inscription in honor of the Great Yu ( ~ 2200- 2100 B.C), who as the story goes, conquered a flood. The inscription says " When the Yellow River is at Peace, the Nation is at Peace". Flood control required enormous civic resources and cooperation and the ability to tame river waters gave political and moral legitimacy to the ruling class.The taming of nature using cooperative people power and as a sign of a strong united society has deep roots in Chinese political thinking.
One particular vexing problem was the very high rates of silt load carried by the Yellow River. A vast area of the Yellow River watershed drains the Loess deposits of north central China. This is a plateau made up of loose friable sand and silt blown in from the Gobi desert of Mongolia. Erosion of Loess fills the river with sediment. There is 300 grams of sediment for every kilogram of Yellow River water giving the river a reddish golden color. Erosion has carved the Loess Plateau in to a landscape of ravines and gorges. The American journalist Edgar Snow in the 1930's described it thus:
" an infinite variety of queer, embattled shapes - hills, like great castles, like ranges torn by some giant hand, leaving behind the imprint of angry fingers. Fantastic, incredible and sometimes frightening shapes, a world configurated by a mad God - and sometimes a world of strange surrealist beauty. "
High rates of sedimentation meant that the Yellow River bed could aggrade or rise, increasing the risk of the river breaking its banks and flooding the countryside. Dyke building to constraint the river channel began as early as the seventh century B.C. by the state of Qi.
Constant dredging of the Yellow River and the associated tributaries and canal systems ( the Grand Canal) was also required to maintain a channel deep enough for navigation to move armies and grains from south to north. River channel and canal maintenance acquired a new urgency when Zhu Di known as the Yongle Emperor of the Ming dynasty moved the capital north from Nanjing in the eastern province of Jiansu to Beijing in the early 1400's. The rational was probably to keep the political center closer to the armies amassed on the northern frontier where the Ming faced a threat from the Mongol and Manchurian steppe people. Later in the 1600's, the Manchurians overthrew the Ming and established the Qing Dynasty. Although over time, the Qing assimilated into the larger Han cultural milieu, they felt more at home in the north of the country. That meant the Yellow River and the Grand Canal system had to kept in top navigable order.
Desperation to unclog the river channel spurred technological innovation.
An extract:
Removing silt from the Yellow River demanded some impressive technology, not to mention serious organization. The Song government set up a Yellow River Dredging Commission in 1073 which began to deploy boats equipped with dredging tools. The vividly named "iron dragon-claw silt dispersing machine" was a great rake pulled along the riverbed to agitate the silt and return it to the flow. This principle was extended with the 'river-deepening harrow', a 2.5 metre-long rotating beam fitted with iron spikes, like a thresher for riverine mud. The Ming imperial censor Chen Bangke introduced new techniques in the late sixteenth century, such as wooden machines set rolling and vibrating by the current to constantly stir up the sediment. In the dry season Chen proposed simply digging out the silt manually.
The Ming official Pan Jixun in 1565 or so came up with a solution that has made him one of China's water heroes. He pointed out that if one confines the water flow to a narrow channel, it will have enough strength to scour the sediment off the river bed. There would be minimal need for laborious manual dredging. He may have borrowed the idea from a Confucian text of the Han era (~200 B.C - 220 A.D) called Zhou li (Rites of Zhou) which stated "A good canal is scoured by its own water".
Chinese philosophical tradition impacted river management strategies. Daoists argued that the river be given room to spread and build wide floodplains in concert with the principle of wu wei which could be read to mean "do nothing" or "having a yielding attitude". Confucians on the other hand wanted the river to be managed by human engineering and recommended the construction of high dykes to keep the river channel narrow and constrained.
Joseph Needham, the noted historian of China writes that 'during twenty centuries the two schools contented'.. 'and neither proved wholly successful'.
I hope to persuade you that energy is central to evolution, that we can only understand the properties of life if we bring energy into the equation..... I want to show you that the origin of life was driven by energy flux, that proton gradients were central to the emergence of cells, and that their use constrained the structure of both bacteria and archaea. I want to demonstrate that these constraints dominated the later evolution of cells, keeping the bacteria and archaea forever simple in morphology, despite their biochemical virtuosity. I want to prove that a rare event, an endosymbiosis in which one bacterium got inside an archaeon, broke those constraints, enabling the evolution of vastly more complex cells. .....Finally, I want to convince you that thinking in these energetic terms allows us to predict aspects of our own biology, notably a deep evolutionary trade-off between fertility and fitness in youth, on the one hand, and ageing and disease on the other.
The last book I read on the evolution of complexity was Mark Ridley's The Cooperative Gene which described the many evolutionary inventions that suppress genomic conflict and make multicellular bodies workable. Nike Lane writes at a more fundamental level of the energy currency of the cell. Feeling very excited about this book. I am sure to learn a lot.
But the ubiquitous and ambivalent relationship that the Chinese people have had with water has made it a powerful and versatile metaphor for philosophical thought and artistic expression, and its political connotations can be subverted and manipulated in subtle ways for the purposes and protest and dissent. These meanings of water are more than metaphorical. Because the lives of everyday folk has always depended on water, the river and canals mediate their relationship to the state. Water -too much of it,or too little - has incited the people to rise up and overthrow their governments and emperors. Burgeoning economic growth now places unprecedented pressure on the integrity and sometimes the very existence of China's waterways and lakes. Not only can China's leaders ill afford to ignore this potential brake on economic growth, but the environmental problems are leading to more political pluralism in a nominally one party state.
Sweeping... from the Qin Dynasty (200 B.C.) to the present..
I am ashamed to admit this, but these days I just shrug away the various instances of poor science reporting I notice in the Indian media. But enough outrage has been building up over a couple of particularly bad misrepresentations of scientific findings to prompt this rant.
One shudders with embarrassment at this jingoistic hyperbole. The study is an international collaboration. Why the chest beating?
The article in Deccan Herald on July 26 by Kalyan Ray completely misrepresents the evolutionary story of Homo sapiens. Here are the sentences which go badly wrong -
"Andaman’s Jarawas and Onges are descendants of a completely new family of early men unknown to science so far".. "The discovery has the potential to open up a new window in the history of human evolution by suggesting that Homo heidelbergensis—the first group of men who came out of Africa—had given rise to multiple lineages and not just the Neanderthal and the Denisovan—the two known branches from which all modern human beings have evolved".
The writer is suggesting the modern humans evolved entirely from Neanderthals and Denisovans outside Africa and that this new research is showing that the Andamanese are descendants of a yet third branch of humans based outside Africa.
This picture given by Kalyan Ray is false. Take a look at the hominin family tree presented in the research paper.
It presents our current understanding of human evolution and migration and admixing events between different branches of hominins. Modern humans migrating out of Africa about 60 thousand years ago met and admixed with the Neanderthals and Denisovans who were branches of an earlier wave of human migration out of Africa. This earlier wave of migration may have taken place about half a million years ago. This admixture between archaic and modern humans resulted in all living non -Africans having 2%-4% Neanderthal ancestry with additional Denisovan ancestry more common in Melanesians. Now, this study is proposing that another unknown extinct hominid, a possible third diverged population from those earlier migrations, contributed a small amount of ancestry to south Asians. The Andamanese may be taken as an approximate proxy of the original modern humans who entered the Indian subcontinent from Africa since after diverging from a common South Asian population they have admixed less with other modern humans.
Another quibble is the sentence "Hominids are ancestors of the great apes and humans". Well, hominids is a grouping that includes both extinct and living great apes and humans. So yes, some extinct hominid would have been our ancestor, but modern humans are hominids too. As an aside, to confuse matters further, Hominin are the group that includes the extinct and living members of only the human family, excluding the chimpanzee, gorilla and orang-utans.
This piece which appeared in the Times of India on June 6 is referring to a paper about the link between Holocene monsoon record and the evolution of Harappan civilization. The authors also suggest a revision of the chronology of the various Harappan cultural stages. Here is their proposed chronology.This is based mainly on the chronology proposed earlier by G.L Possehl. The authors of this study augment that with new dates from two samples.
"The successive cultural levels at Bhirrana, as deciphered from archeological artefacts along with these 14C ages, are Pre-Harappan Hakra phase (~9.5–8 ka BP), Early Harappan (~8–6.5 ka BP), Early mature Harappan (~6.5–5 ka BP) and mature Harappan (~5–2.8 ka BP)"
And here is the conventional chronology
"Conventionally the Harappan cultural levels have been classified into 1) an Early Ravi Phase (~5.7–4.8 ka BP), 2) Transitional Kot Diji phase (~4.8–4.6 ka BP), 3) Mature phase (~4.6–3.9 ka BP) and 4) Late declining (painted Grey Ware) phase (3.9–3.3 ka BP). This chronology is based on more than 100 14C dates from the site of Harappa and nearby localities".
Here is the chronology Mr. Mehta presents:
The first line in the introduction section of the research paper makes it clear that all dates are presented in BP (Before Present). Yet Nalin Mehta in his article bungles up and without applying the necessary correction presents the chronology as representing dates in BC. The difference is 2000 years! For example, 5000 BP is 3000 BC.
Another big error he makes is lumping all the Harappan cultural stages into one mature phase spanning 8000 -2000 BC ! This gives an erroneous view of the evolution of Harappan society. The mature phase represents urbanization. The earlier cultural stages were rural antecedents represented by farming and pastoral communities and even earlier human settlements in this area. By terming the entire time span of Harappan culture as belonging to the mature phase, Mr Mehta gives an impression that Harappan cities were as old as 8000 BC. This is certainly not the case. This new study revises the mature phase of the Harappan culture from the accepted ~2600 BC-2700 BC (4700 BP) to ~ 3000 BC (5000 BP). This proposed revision at one cultural site should not be taken to mean that dates for cities like Harappa, Mohenjodaro, Dholavira will suddenly be changed to 3000 BC. Their chronology needs to be ascertained independently. As of now, large number of C14 and thermoluminescence dates have secured the age of these cities to be around 2700 BC or so.
One has to be careful with terminology. Mr Mehta uses dates as old as 8000 BP (wrongly presenting them as 8000 BC) to imply that the Harappan civilization is older than the Paraoahs of Egypt. Such a comparison is meaningless. These earlier dates represent a rural society. No doubt there was population and cultural continuity of these earlier people with the later urban phase, but you can say the same thing about pre-urban Egyptian and Sumerian cultures evolving into a full fledged urban civilization. There was a long pre-urban phase from 5-6 millenium BC in Eygpt and Sumer (synchronous to the Indus region) with central political consolidation and urbanism by around 3100 BC in Egypt when the first dynastic kings known as the Pharaohs seized power. In Sumer, the transition from rural to urban took place even earlier with cities like Uruk gaining prominence well before 3500 BC.
The differently named cultural stages of the Indus valley carry a specific meaning in terms of societal complexity and cultural changes. You can't just call everything mature Harappan and then claim that the finding requires some kind of a fundamental rethink of Harappan society.
As it happens, the dates presented in the paper that Mehta is ga-ga about are not new. Archaeologists have been aware of the alternate chronology presented by G.L Possehl for about 15 years now! In that sense there is nothing revolutionary about the chronology presented in this paper.
Something significant went unnoticed and unreported amongst all the hoopla surrounding the recent paper on Harappan civilization and its link to climate change. The theory of the glacial Sarasvati got dumped. The paper does not even mention it as a possible reason for the reduced water flow in the Ghaggar. Based on its geographic description in the Rig Ved the Ghaggar has been equated with the Vedic Sarasvati river.
The glacial river theory proposed that the river Yamuna and the river Sutlej, both glacially sourced from the high Himalaya, earlier flowed into the Ghaggar. They changed course around 2000 B.C or so to their present day channels. This switch starved the Ghaggar of water and it became a smaller ephemeral river. This theory also accepts that climate change did occur, but the main reason for the apparently sudden water shortage was the changing of course of the glacial rivers.
Until a few years ago, there just wasn't enough detailed work done on the sediment provenance (comparing characteristics of old channel sands of Ghaggar with those of present day Yamuna and Sutlej) and channel chronology of the Ghaggar system to say whether this theory was correct. But work published in 2012 on river sediment provenance tied to a chronology and analysis of fluvial landforms have shown that the Yamuna and Sutlej did once flow into the Ghaggar but changed course to their present locations by late Pleistocene-earliest Holocene, thousands of years before the Harappan civilization. Since this work, no new data challenging these results has appeared. Scientists as evidenced by this paper appear to now accept that the Ghaggar was a monsoonal river right through the Holocene.
This result has annoyed not only geologists who had proposed the glacial river theory but also supporters of the indigenous Aryan theory. They had used the glacial river theory to time the presence of the Vedic people in the plains of Haryana and Punjab before 2000 B.C. The reasoning was that the Rig Ved describes a mighty Sarasvati flowing down from the mountains. Hence, it must have been glacially sourced and must have been the present day Ghaggar. The Aryans would have had to have been present in northwest India before the river became less mighty i.e. before 2000 B.C. This according to them destroyed the Aryan Invasion /Migration theory which proposed that the Aryans, who were a Central Asian people, entered India after the Harappan civilization disintegrated.
Where do we stand now in terms of the Aryan question in the light of the new results on the Ghaggar river?
Well, in exactly the same place as before! It was always futile to try to link the condition of the river, whether glacial or monsoonal to the question of the origin of the Aryans. The Rig Ved describes a big river. It doesn't really say that it was glacial in origin. If the Aryans had been present in the Punjab and Haryana before around 2000-1800 B.C. they would have seen a larger Ghaggar (due to a wetter climate).
At the same time, this supposed earlier presence of the Aryans in the Harappan realm does not automatically answer the question of their origins. They just as well could have represented an earlier wave of Central Asian migrants who settled in northwest India during the latter stages of the Harappan civilization. For this same reason, the indigenous Aryan theory would not have been strengthened even if the river had turned out to be glacial during Harappan times.
The geological history of the river cannot solve this riddle. A combination of archaeology, deciphering the script and genetics will be required. We await with anticipation the results of the DNA recovered from Harappa age skeletons.
In the meantime, people who tend to read too much into Rig Vedic hymns should accept that the Vedic poets who wrote (source) -
"This (Sarasvati river) has shattered mountain peaks with her fast and powerful waves, just (as easily) as one uproots the lotus-stems, let us invoke her,who strikes what is far and near, with holy hymns and prayers"..
and ..
"Whose boundless, impetuous and swift-moving flood gushes forth with a tempestuous roar"
may have been really looking at a brown colored muddy, silty, sluggish river originating in the Siwalik hills.
