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.
 
..