Is Mount Kailash The Oldest Mountain In The Himalaya?

No. It is not.

Although, according to this tweet it is.

The person tweeting as CBG-san (@OnlyNakedTruth) uses Pranay Lal's book Indica: A Deep Natural History Of The Indian Subcontinent as the source (page 268-269), and also refers to an analysis done on Mount Kailash rocks. I could not make out the source of the table of analysis. They show the age of Mount Kailash Formation as ranging from around 30 million years to around 10 million years old.

Let me get one technical point out of the way. Geologically,  Mount Kailash is not in the Himalaya. It is part of  the Asian continental plate. These mountains are known as the Transhimalaya. Locally, these ranges are also called the Gangdese Shan. The Himalaya are the deformed and uplifted rocks of the Indian plate. This is a quibble though. I appreciate that the larger point is whether the rocks of Mount Kailash were uplifted very early during the India-Asia collision process.

The Mount Kailash range is made up of thousands of feet of sediment of the Kailash Formation, sitting on granitic rocks of the Gangdese batholith. These granitic rocks formed within the southern edge of the Asian continent. As the Indian plate dived underneath Asia, magmas formed deep inside the Asian plate. Blobs of this magma rose and solidified in the subsurface of the Asian continent forming the Gangdese batholith (a large body of granite). This magmatism took place between 100 million and 45 million years ago .

There are new dates available now for the Kailash Formation, which was deposited on top on this granite. Radiogenic dating of lava flows inter-layered with sediment indicates that the Kailash Formation accumulated between 26  million years and 21 million years ago.

This timeline indicates that around 26 million years ago the southern margin of the Asian continent and the India-Asia collision zone subsided. The nature of the sediments indicates that a long chain of lakes formed in narrow depressions. These lakes were receiving sediment eroded from elevated ranges to the north. Organic matter accumulating in these lakes have been transformed into coal layers. There is also an absence of pollen grains of temperate or high-altitude plant species. This sediment composition points to a lower elevation and warmer water setting of these lakes, which geologists speculatively place between 1000 m to 3500 m. Presently,  Kailash Basin sediments are exposed at altitudes greater than 6000 m.

The graphic below shows the depositional environment of the Kailash Formation

Source: DeCelles et.al. 2016- Oligocene-Miocene Great Lakes in the India-Asia Collision Zone. 

The rocks that make up Mount Kailash are younger than 26 million years. They formed nearly 30 million years after the collision of the Indian and Asian continents.

High topography already existed along several belts in the collision zone before 26 million years ago.

First, the southern margin of the Asian continent must have been elevated perhaps as early as 45 million years ago, since this terrain was the source of sediment into the Kailash Basin. More direct methods of estimating elevation also suggest high elevations in this region by  35-40 million years ago. The ratio of the two isotopes of oxygen (O18 to O16), bound in calcium carbonate minerals,  is temperature dependent. Measurements from southern Tibet indicate paleo-elevations of around 5000 m by 35 million years ago.

Second, the zone of India-Asia collision (Indus-Tsangpo Suture), and the Tethyan Himalaya belt (the northernmost Himalayan ranges) had been uplifted by 45-40 million years ago. The evidence for this comes from the composition of foreland basin sediments to the south. As India collided with Asia, a depression formed in front of the rising mountain chain. This foreland basin (which later was uplifted to form the Siwalik ranges) began receiving sediment derived from the erosion of the newly uplifted Himalaya.

Eocene age (45-35 million years) sediments in this foreland basin contain rock fragments and minerals inherited from the Indus-Tsangpo Suture and the Tethyan Himalaya. Younger foreland sediments of Early Miocene age (between 24 and 15 million years) contain fragments of the Tethyan Himalaya as well as the newly emerging Greater Himalaya.

The timing of uplift of the Greater Himalaya is also hinted at by geochronology. The radioactive clock inside muscovite (a type of mica) starts ticking below around 350 C. Clocks in other minerals like zircon (zirconium silicate) and monazite (rare earth phosphate) are set at higher temperatures, at 700 C and 600 C respectively. A sample may contain all three of these minerals, as Greater Himalayan granites and gneisses often do. Their dates of formation track a cooling history, as the rock is uplifted from deeper crustal levels to shallower regions.

Such work by geologists have shown that the Greater Himalaya were exhumed between 21 million and 16 million years ago. Exhumation in such collisional settings is linked to rapid surface erosion and formation of topography. Mike Searle's book Colliding Continents: A geological exploration of the Himalaya, Karakoram, & Tibet describes these different methods for assessing rock ages and cooling histories.

A different geochronology method known as fission-track dating,  that measures radiation damage in crystals of zircon (zirconium silicate) and apatite (calcium phosphate) to estimate when the rock cooled below 200 C to 100 C indicates that the Kailash Formation was uplifted later than 17 million years ago.

Ranges on the Asian continent (Gangdese Shan), as well as the Indus-Tsanpo Suture in the collision zone and the Tethyan Himalaya belt to the south on the Indian plate, are older than Kailash. The Greater Himalaya was uplifted around the same time as the Mount Kailash Formation.

This evolution of topography in the Himalaya and along the southern margin of Asia is shown in the schematic below. Orange arrows indicate transport of sediment from source to basin. Black arrows show fault motion.

I've always been struck by a disconnect in Pranay Lal's book. His end notes are detailed and summarize the state of research fairly well. However, there are many basic mistakes in the main text. I made a list of the many geology errors in his book in an earlier post titled Book: Indica- A Deep Natural History of the Indian Subcontinent.

It is simply not accurate to say that Mount Kailash is the oldest mountain in the Himalaya. The southern margin of the Asian continent was elevated soon after the India-Asia collision, probably by 45 million years ago. But the Kailash Formation did not rise until after 17 million years ago. It is a much younger component of the Gangdese Shan or Transhimalaya.  Mount Kailash's classic pyramidal shape evolved during the ice ages of the Quaternary Period beginning 2.58 million years ago, when glaciers dug out valleys and cut back slopes, forming smooth sided and sharp edged peaks.

Ganga Water: Future Availability

The Ganga river basin is being modified by the building of infrastructure to trap and divert water. There are many environmental repercussions resulting from this dam and canal construction. That is not the topic of this note.
 
Will there be enough water available for these different projects?

First, the Inland Waterways project will need water to be released from upstream dams to maintain a certain water depth in the navigable channel in the summer months. Second is the River Linking Plan, based on the rationale that there is excess water in the Gangetic system. The plan envisages transferring Ganga system water during the summer months to the southern Peninsular rivers. And third, the Uttarakhand dam building companies will try to keep as much water locked up behind dams for power generation in the summers.

Over and above the water requirements of these projects, environmental regulations will require a  certain amount of water flow to be maintained throughout the year in the river. This will be detrimental to the river linking and power generation projects.

Each of these massive waterworks will be competing for a limited amount of Ganga water during the same time of the year. This allocation problem will lead to water disputes, both, among the managers of these projects, and across different States. As a result, these projects are unlikely to operate optimally.

I haven't come across an official water budget analysis projected 100 years into the future, that takes into account water availability and the impact that these three projects will have on each other.

Cracks In A Rock And The Western Ghat Escarpment

A friend sent me this picture of a section of the Western Ghat escarpment. It is taken from Jivdhan fort, looking north towards the hook nose of Naneghat. This location is about a hundred odd kilometers west-north-west from Ahmednagar town. Naneghat was a mountain pass for travel between the coastal plain and the plateau.

Photo credit: Rajesh Sarde

The yellow bloom makes a pretty contrast with the grey basalt. My geology eye was drawn towards something else; a suspiciously straight flowing stream, which I have highlighted with an arrow.

I looked at a satellite imagery of this location and the stream is seen following a fracture zone (black arrows)  that cuts across Jivdhan fort as well. The escarpment area is riddled with such fractures. They occur as north-south, northwest-southeast, and northeast-southwest (brown arrows) trending sets.

These fractures are regions of shattered rock. That zone erodes away quicker. Water flowing in the linear depressions that form enhance this topographic difference and eventually cut deep straight valleys.

Large fractures or cracks along slopes causes slabs of rocks to cleave away from mountain sides. Slopes retreat due to such rock falls. A large crack is seen in the picture just a few feet away from where my friend took his photograph. At some point a portion of rock will detach itself and Jivdhan fort will become that much narrower.

Look at the zoomed out satellite imagery of this area. The plateau edge has been fragmented into isolated hillocks, mesas and pinnacles by enhanced erosion along fractures oriented in various directions. You can follow some of these fractures (white arrows) to the straight edges of the escarpment suggesting that slab breakoff has played a role in shaping the morphology of the cliff line.

Such fracture systems not only have formed a landscape of mesas and pinnacles but have caused the Western Ghat escarpment to retreat eastwards for at least tens of kilometers from its original location. The escarpment is a legacy of the breakup of the western margin of India with Seychelles at the end of the eruptions of the Deccan Basalts. At that time in the Paleocene (~60 million years ago), continental stretching caused the formation of a series of north-south oriented faults which sloped (dipped) to the west. The westerly block of each of these fault sets sank, created a staircase like crustal structure descending towards the west, with west facing cliffs. The Western Ghat escarpment would have been the easterly most of these cliffs.

See the schematic below which shows this staircase crustal structure of the western margin of India.

The red portion would have been the original extent of the Deccan plateau. It has retreated eastwards over several millions of years. As a result, the coastal plain became progressively broader. Give a thought to the humongous amount of rock that has been removed by erosion.

Along the west coast the erosional  retreat has not wiped clean all evidence of the original plateau. From the coastal plain rise isolated ranges and mesas. The hill station Matheran, where people go to catch the cool wind and a spectacular view, is a fine example.

See the satellite imagery below.

Matheran was where the plateau edge and escarpment once was. It has now moved eastwards (arrows) leaving behind an erosional remnant,  a splendid outlier of the Deccan plateau rising abruptly from the plains.

Let's end with a 3D view of the escarpment along the Jivdhan-Naneghat area.

If you take a flight out of Pune to Delhi, the plane will fly a northerly route parallel to the plateau edge for the first 20-25 minutes of your journey. The Western Ghat escarpment appears as it does in the tilted perspective above, a sinuous line of majestic black cliffs, testimony to the forces of volcanism, continental breakup, and erosion.

A section of this stunning landform deserves to be included in our National Geological Monuments list.

Human Evolution: Focus On Africa

In a lecture delivered to the American Society for Human Genetics, paleo-anthropologist John Hawks gives a lucid summary of the African record of human evolution.  The divergence of the hominin lineage from other apes took place in Africa between 5 and 10 million years ago. Hominins began dispersing out of Africa in pulses beginning 2 million years ago. The vast majority of hominins though continued to live and evolve in Africa. Yet, popular stories of human evolution focus on people leaving Africa and colonizing the world. What has been happening in Africa all along gets sidelined in this narrative.

The “out of Africa” slogan came from well-intentioned scientists. They thought that by emphasizing the idea of an African origin, they would send a clear message that Africa had an important place in evolutionary narratives. That much is true. Africa was the center of human origins. But “out of Africa” stories focused almost exclusively on dispersal, as if it were an exodus. Africa’s place in these stories was the place that people left.

John Hawks refocuses our attention on the African fossil and genetic record that tells us that Africa always has occupied a central place in our evolutionary story.

He points out that this record has yielded three big insights:

First, modern humans did not originate in a bottleneck after 200,000 years ago. Our origin was much deeper in time than this.

Second, our species originated in Africa from deeply structured ancestral populations. These were much more different from each other than any human populations are today. We do not know how they interacted or which gave rise to living peoples.

Third, some of these deeply divergent populations survived in Africa until recent times. During the time of human origins, “modern” humans were not alone. 

The term bottleneck means that at some time in our past there was a drastic reduction in our population size and genetic variability.

Anyone interested in the topic of human evolution should read this article.

Extreme Fieldwork In The Karakoram Mountains

This remarkable passage from Colliding Continents by Mike Searle:

"After two weeks of acclimatizing on the Lobsang Spire and Cathedral granite cliffs above camp and establishing our attack camp full of supplies we were ready to go for the summit. I was keen to climb a line up through the granite cliffs in order to map out and sample a vertical profile through the granite batholith. These Karakoram granite spires provide a unique opportunity to map and sample over 3 kilometers deep into such a batholith. We left once again at 3 a.m. for the dangerous plod through the icefall, and arrived at the ice-shelf camp at about 10 a.m. As soon as the sun came on to the glacier, freezing night-time temperatures soared up to incredibly high hot temperatures above 35⁰C. Frozen icicles dripping off the rock face turned into trickles of water and then into torrents. Huge avalanches of powder snow exploded down the steep granite faces all around us. This was nature in the raw: powerful, frightening, but at the same time immensely beautiful.

Next morning we left at the usual 3 a.m., roped up, and started climbing the steep ice face on the south face of Biale. Very soon the ice petered out and we were on vertical solid granite. Climbing vertical granite walls with a 20 kg rucksack, a rack full of slings and nuts and big plastic double boots was not easy. I was trying to record geological observations in the granites and put those onto a map at the same time; the sample collection was to be done on the way down. After two days of this steep and scary climbing we finally broke out of the cliffs onto a  large snowfield that led up to a knife-edge ridge. As we approached the ridge the most spectacular mountain panorama I have ever seen unfolded in front of us. We were in the middle of the Karakoram, with huge glaciers flowing all around us, separating ridiculously steep cliffs of pure granite".

The Himalaya ranges are the northern edge of the Indian continental crust which was deformed during the India-Asia collision. Similarly, the Karakoram ranges are the southern margin of the Asian continent which was deformed during the India-Asia collision. Mike Searle and his colleagues were trying to work out their deformation, metamorphic and uplift history.

In the satellite imagery below, I have overlain the major lithologic and structural elements of the India-Asia collision zone. The imagery covers the central and eastern Karakoram ranges.

The southern margin of the Asian plate is made up of two amalgamated terrains. In the mid Cretaceous (~110 million years ago) a separate terrain/microplate known as the Kohistan-Ladakh block existed south of the Asian continental mainland. As the Indian plate pushed northwards, oceanic crust which made up its leading edge dove under the Kohistan-Ladakh terrain. As the dense crust subducted, it heated up, releasing water trapped in the sediment cover. This water migrated upwards, lowering the melting point of rocks in the lower part of the Asian plate (mantle) and triggering melting. Magmatism and volcanism formed an intra-oceanic island arc system above the subduction zone. The Dras Arc Volcanics are part of this island arc, which continues westwards into Kohistan. The Ladakh batholith represents the root of this arc system, made up of granitic and granodioritic magma congealed in the deep subsurface. Volcanic rocks at the famous Khardung-La Pass are the surficial expression of the Ladakh magmatic system.

Between 70-80 million years ago, the Kohistan-Ladakh arc collided with the Asian mainland forming a composite terrain. The Main Karakoram Thrust-Shyok Suture marks the zone of collision between these two terrains. The Indian plate continued subducting under the Asian plate. Magmatic growth of the Kohistan-Ladakh batholith continued until about 50 million years ago. By this time, the Indian oceanic crust had been consumed and as a result the Indian continental crust collided with Asia. This collision zone is marked by the Indus-Tsangpo Suture.

The pre-collision tectonic setting of the Kohistan-Ladakh arc is depicted in the graphic posted below.

Source: Searle et. al. 1999

There is another model which proposes that the Kohistan-Ladakh arc first collided with the Indian plate around 85 million years ago. Collision of this combined plate with Asia then took place around 50 million years ago. I am ignoring this debate in this post.

Continental collision lead to crustal thickening on both sides of the suture zone. In the Karakoram region, high temperatures and pressures in the lower parts of the thickened crust resulted in metamorphism of buried rocks (Karakoram Metamorphic Complex). Eventually, temperatures in the buried crust exceeded the melting point of rocks, triggering magma generation. These post-collisional crustal melts intruded the surrounding metamorphic rocks forming sills (intrusions parallel to the layering) and dikes (intrusions cutting across the layering). Granites formed in this manner are most conspicuously exposed in the region around the Baltoro Glacier. These granites form many of the jagged spires and pinnacles that Mike Searle describes so vividly in his book. They are part of the Karakoram batholith.

Crustal melting and granite magma formation occurred in the thickened Indian plate as well, south of the Indus-Tsangpo suture zone. These granites are exposed along the crest of the High Himalaya ranges. The Himalayan post-collisional granites are beautiful to look at.  Faceted crystals of black tourmaline and red garnet, along with gleaming flakes of white mica, are set in a white to pink colored matrix made up of quartz and feldspar. The picture to the left shows a tourmaline bearing leucogranite from the Greater Himalaya Sequence making up the Panchachuli range in Kumaon, Uttarakhand. I collected it from the moraines of the Panchachuli glacier.

The Karakoram Batholith is a composite body made up of magmas formed during different times. Older granitic rocks (150-70 million years ago) in this batholith formed in an Andean type margin setting wherein the Tethyan ocean crust was subducting under the Asian continental plate.

Certain metamorphic minerals like kyanite, sillimanite and garnet are thermobarometers. Their elemental ratios tell us about the temperature and pressure prevalent during mineral growth. Geologists estimate that the sillimanite and kyanite bearing Karakoram metamorphic rocks were formed at 35 km depth. These metamorphic rocks, along with the earlier formed granites of the Karakoram batholith, eventually partially melted to form the Baltoro granites.

Geologists have also been able to work out when metamorphism and melting took place. Using radiogenic uranium isotopes trapped in zircon crystals they find that peak metamorphism took place in several pulses. The oldest metamorphic event occurred around as early as 60-65 million years ago, with the heat source likely being the collison of the Kohistan Arc. Subsequent metamorphic pulses, driven by crustal thickening,  have been dated to about 45 million yeas ago and an even younger event to about 16 million years ago.

Magmas which form the Baltoro granites intruded and crystallized between 20 million to 13 years ago, similar in age to the post collisional leucogranites of the High Himalaya which are 24 million to 15 million years old . Crustal melting and granite formation in the Karakoram continued sporadically until around 9 million years ago.

The deep crustal processes occurring in the Karakoram region were also taking place eastwards in the thickened crust below Tibet. In the Karakoram, metamorphic rocks and granites formed in the lower levels of the crust now lie spectacularly exposed along the steep mountain sides. Erosion over the past 30 million years has removed over 35 km of overburden, exhuming these deep crustal layers. The Tibetan plateau however is made up of sedimentary and volcanic rocks. Only the uppermost parts of the crust are exposed here. Karakoram equivalent high grade metamorphic rocks and crustal melt granites, which undoubtedly exist in this region, still lie deeply buried in the subsurface.

Why is there such a difference between Karakoram and the Tibetan Plateau in the level of crustal exposure?  Take a look at the satellite imagery. Karakoram is covered by snow, while much of the Tibetan Plateau lies bare. Karakoram receives rain and snowfall from both the India summer monsoon as well as the north westerlies bringing winter moisture from the Mediterranean and Caspian areas. Tibet lies in the rain shadow of both these systems.  High rates of stream incision and the enormous erosive power of glaciers has resulted in high rates of exhumation in the Karakoram, eventually exposing deeply buried crust. Low erosion rates in the arid Tibetan region has failed to cut deeply into the crust, resulting in exposure of only the uppermost levels of the crust. Both Karakoram and Tibet have an average elevation of about 5000 meters. In the Karakoram though there is prolific relief, with peaks in the 7000-8000 m range and valleys at 2000-3000 m elevation. Relief in Tibet is subdued.

Climate plays an enormous role in shaping the topography and evolution of mountains.