Landscapes: Sunderdunga Valley Kumaon Himalaya

In mid November, I explored the Sunderdunga valley in the Kumaon region of Uttarakhand. It was a good rigorous walk through some extraordinarily beautiful landscapes. This area is better known for the famous Pindari Glacier trek. Kafni Glacier is another option for trekkers. All three routes begin at village Khati. The picture taken of the high ranges from nearby Dhakori shows the three glacial valleys.

And here are some more photos of the route with a brief commentary.

The entrance to Sunderdunga valley with the vigorous Sunderdunga river flowing through.

The first day walk to Jatoli village was through golden and green forests.

Village Jatoli in the mid November sun. We stayed there overnight at the Kumaon Mandal tourist guesthouse. They provide excellent clean accommodation. 

About 4 km walk upstream from Jatoli the next day and the land cover changes abruptly. The forest is gone. There is no marked trail from here on and a walk over a rugged boulder strewn region begins. 

We navigate our way over steeply dipping metamorphic rocks and scree cones. 

Numerous rock falls make for tricky passages. You can spot my companions climbing their way up the steep slope. 

After slogging for about 8 km through this terrain we arrive at Kathaliya, situated at about 10,500 feet ASL. We have climbed about 2500 feet from Jatoli to Kathaliya. A small trekkers shed has been constructed here. We stayed there for the next couple of days. 

Next morning, ahead of Kathaliya camp, we encountered the full glory of Sunderdunga valley. Here, it is a occupied by a wide boulder strewn river bed with several small active channels. The earthy colors of rock and grass were in stunning contrast to the blue sky. A solitary shepherd's hut can been seen in the lower right. 

Another view of the valley.

Boulder bed! The surrounding Greater Himalaya are made up of high grade metamorphic rocks. You can spot quartzo- feldspathic gneiss, amphibolite gneiss, mica schist and gneiss, and mica, garnet, and kyanite bearing schist and gneiss in the river bed. Quite a treat to walk along this metamorphic treasure! 

 Crossing the wider channels on rickety wooden bridges was fun! 

Here we are near Maiktoli Top, a high vantage point. Jagdish Bisht, me, Ratan Singh Danu, Lucky, and Kapil. They made my trip safe, comfortable, and memorable.

Why I go to these places. A clear view of the bands of metamorphic rocks exposed along the spectacular cliff face of the Sunderdunga ridge!

 

Village Khati is such a pretty place.

The high bare peaks in the background speak of a worrying trend. Everyone I talked to told me that this trek would have been impossible a few years ago in mid November. The upper part of the valley and the rocky ridges would have been blanketed in a thick snow pack. This area still had not received a single snowfall when I left on 22nd November. The two or three big snowfalls of the year now occur mostly in January and February. The pastoral and agriculture economy depends on a healthy winter snow cover to rejuvenate the high meadows, and to replenish springs and streams.

My guide tells me that Sunderdunga valley is the tougher route amongst the three treks to the nearby glaciers. I am so glad I walked this valley!

Milam Glacier Trail - Geology

Geology enthusiasts will find the Milam Glacier trail captivating. The river Goriganga emerges from the glacier and flows in the Johar valley in this region. I walked the trail in Mid October, and came across a variety of geological features of interest. The trail begins in the village of Lilam, just north of the town of Munsiyari in the Kumaon region of Uttarakhand. It passes through the steep Greater Himalaya, and later northwards, through the Tethyan Himalaya.

The map below, intended more to show the geological set up, shows the trail as a red line. It depicts the trail only until Rilkot. Milam, the end of the trail,  is about 20 km north of the extent of this map.  

Source: Patel et.al. Geology, Structural and Exhumation History of the Higher Himalayan Crystallines in Kumaon Himalaya, India

The Greater Himalaya (GH) and the Tethyan Himalaya  (TH) are two thick slices of the Indian crust which were moved southwards by great thrust faults as India collided with Asia about 50 million years ago. Both the GH and TH are made up of sequences of rocks that formed on the northern margin of the Indian plate over a vast period of time. The rocks range in age from the Proterozoic to the Eocene (1.8 billion to ~50 million years old) The GH consists of rocks which were buried to great depths during the India-Asia collision and metamorphosed at high temperatures and pressures. On the other hand, the TH rocks experienced only shallow burial and show a light metamorphic imprint while retaining many of their primary sedimentary characteristics. 

This post is mainly a visual journey intended to help trekkers make sense of the geology they will encounter along the trail. Short explanations accompany the pictures and videos. 

The map above shows three major fault zones. All three dip (tilt) north.  In Munsiyari, while you wait for your trekker permit to get processed, walk down the main bazaar road towards the petrol station. Keep a watch for the rock outcrops on your right. These are limestones of the Lesser Himalaya caught up in the Munsiyari Thrust Zone, the southernmost of the faults in this area. 

The picture collage shows the deformation in the fault zone rocks. Shearing along the fault has produced a shiny smooth surface and a mica like character to the bedding surfaces. They will feel like talc to the hand, or like porcelain. Sedimentary layers also show folding and striations, two typical deformation features along faults.

This rock below,  know as augen gneiss,  is one of the iconic rocks of the Munsiyari area. It is among the oldest dated rocks in the Himalaya, estimated to be between 1.9-1.8 billion years old. While the limestones near the petrol station are positioned below the fault plane (footwall), the augen gneiss is part of the hanging wall (above the fault plane) of the Munsiyari Thrust. Notice how the white feldspar grain (porphyroclast) is deformed into a sigmoidal shape. The feldpar is an inch in length. White arrows denote the sense of motion along the fault.The Munsiyari Thrust, as is the case with other major thrust faults in the Himalaya, shows a primarily "top to the south up" sense of shear. This means that the thrust direction is southwards.

 From Lilam, at the start of the trail, you will pass through another great fault zone known as the Vaikrita Thrust or the Main Central Thrust. The MCT carry the Greater Himalaya rocks in its hanging wall. Due to soil, scree and vegetation it is hard to see fresh rock outcrops. The picture shows the general disposition of the GH and their appearance (taken from a construction site near Lilam). These banded rocks are called gneiss and they formed when sedimentary rocks were subjected to high temperatures and pressures.

A few kilometers ahead near Bugdiyar, the Goriganga has cut a narrow gorge. It is an awe inspiring site! Check out this video. Permanent link - Goriganga Near Bugdiyar. 

A road is being constructed between Lilam and Milam. Sections of it coincide with the old trail, while in other parts you can avoid the road and walk the old route. Ahead of Bugdiyar, from Nahardevi to Laspa, I walked along the new road which has exposed some amazing rocks. Here, you are walking along rocks which were buried to 20-25 kilometers depth and then exhumed! Conditions were so extreme, reaching more than 800 deg C,  that the sedimentary/metamorphic rocks partially melted to form a rock with igneous and well as metamorphic features. These mixed rocks are known as migmatites. 

The video shows a rock wall with migmatite gneiss. Notice the white bands which is the melt (leucogranite), while the darker layers are the source metamorphic rock. The video spans about 25 feet. Permanent Link - Migmatite Gneiss Nahardevi. 

Another close up of leucogranite cutting across (dike) gneiss layers. The leucogranite magma then gets injected parallel to the layering or foliation, forming a sill (topmost light colored layer).The gneiss layers are about 2-3 feet thick. 

Ahead, in the Laspa area, you walk across the northernmost of the great fault zones, the South Tibetan Detachment System, also referred to as the Trans Himadri Fault. Across this zone, you will notice a change in the metamorphic grade. The gneiss and migmatites give way to low grade metamorphic rocks like slate and phyllite and quartzites. 

The pic shows an outcrop of carbonaceous slates and quartzites intruded by leucogranite (vein is 6-10 inches in width).  The dikes and sills of leucogranites become rarer as you walk northwards and finally disappear by the time you reach Rilkot village. The rocks from hereon along the trail are part of the Tethyan Sedimentary Sequence.

From Rilkot you enter a landscape profoundly shaped by glaciers. The advance and retreat of glaciers since the Last Glacial Maximum (20,000 years ago) has left behind characteristic glacial deposits. The two prominent types of glacial deposits seen throughout this part of the trail are lateral moraines and glacial outwash terraces. Lateral moraines is debris carried by glaciers along the walls of the valley. They are recognizable as linear ridges. Outwash terraces form when glaciers retreat and the meltwater carry and deposit sediment across the valley forming a plain. Subsequently, the river cuts down through these deposits, leaving flat topped terraces high above the active river bed. For more reading on this topic do refer to Nawaz Ali and colleagues work on the glacial history of the Goriganga Valley.

The pic below shows the Goriganga at Rilkot. LM denotes a lateral moraine of the Shalang Glacier (from a side valley near Martoli). Its age is uncertain but some scientists estimate it to be a relict of a glacial advance that took place before the Last Glacial Maximum. T refers to a glacial outwash terrace formed during a period of deglaciation about 12,000 years ago. 

 

Deglaciation between 16,000 years ago and 8,000 years ago resulted in two pulses of sediment deposition. Near Tola village remnants of these two episodes of terrace formation can be clearly seen, marked T1 (younger) and T2 (older).

 The video below shows a delightful steep climb up the Martoli terrace, a few km north of Tola. Erosion along the sides of the terrace has carved out the pinnacles you can see at the top. Permanent Link - Martoli Terrace.  

There are some structurally interesting outcrops of Tethyan strata near Milam. The picture shows steeply dipping near vertical beds which are folded (bracketed by yellow lines). This location is just before Milam village.

 Ahead of Milam village is this nice closeup of folds in slates and phyllite grade rocks. The picture spans about 15 feet in width. The Tethyan Sedimentary Sequence is part of a fold and thrust belt that formed in the early stages of Himalaya mountain building. 

Keep an eye towards the path from Milam village to the glacier. Strewn higgledy-piggledy is multi-colored rubble from various types of sedimentary and low grade metamorphic rocks. These are affected by multiple sets of fractures. I suspect that they come from a fault zone high up and unfortunately inaccessible to most trekkers. I have put together a collage of these pretty looking boulders.

Here is a map of the trail between Rilkot and Milam along with the geological divisions. You can use this to anticipate what type of terrain you are on. Expect to see high grade metamorphic rocks and leucogranites if you walk westwards, as for example towards Nandadevi Base Camp. And you will see sedimentary and low grade metamorphic rocks if you explore the side valleys to the east. 

Source: Nawaz Ali et.al. - Chronology and climatic implications of Late Quaternary glaciations in the Goriganga valley, central Himalaya, India

 As you gaze towards Milam village from a distance two distinct outwash terraces can be clearly seen. Here marked T1 (younger) and T2 (older).

This photo of Milam Glacier shows two beautiful lateral moraines. Notice these have a sharp crest suggesting there are young in age (compare with the LM near Rilkot). They are thought to have formed as recently as the Little Ice Age just a few hundred years ago!  

This trail is a gift to geologists. I did a rather quick nine day walk through the main trail and noticed so much interesting geology. Along this path are vestiges of processes that occurred at different times and at different levels of the crust, from rocks that formed in a seething hot metamorphic cauldron that existed during the peak of Himalaya orogeny 20 million years ago, to glacial deposits from the historical Little Ice Age when children skated on the frozen  Thames River and much of the northern hemisphere experienced intense cold phases.  

A final nod to this fantastic journey. Spectacular leucogranite dikes and sills intruding gneiss on the stretch between Nahardevi and Laspa. 

There is much left to explore. I will be surely going there again.

Milam Glacier Trail - Landscapes

Earlier in the month from October 10th to October 18th, I walked the Milam Glacier trail in the Kumaon Himalaya, Uttarakhand. A four day walk through the Johar Valley from Lilam village near Munsiyari to Milam took me past some fantastic landscapes and geology. 

After an initial breathtaking climb which takes you from about 6000 feet at Lilam to more than 9,000 feet at a high ridge known as Mainsingh Top, the trail descends towards the Indo-Tibetan Border Police outpost at Bugdiyar. After this, a gradual ascent takes you higher, with the rest of the walk undulating between 10,000 to 11,000 feet ASL. I was lucky with the weather. After walking the first two days in belting bone chilling rain the skies cleared and I was treated to some gorgeous views of the High Himalaya. 

I am posting a few pictures of the landscapes along this scenic route. The pictures are roughly ordered from the start towards the end of the trail.

The Greater Himalaya near Bawaldhar, a small resting stop which we came across on the first day.

Another view of the Greater Himalaya in the vicinity of Bugdiyar. Notice the steep slopes, narrow valleys and the sheer rock faces and the cascading Goriganga river. 

A lovely rough trail near the Laspa area. The October colors really makes the landscape radiant. 

After Laspa, the Greater Himalaya made up of high grade metamorphic rocks give way to the low grade metamorphic and sedimentary terrain of the Tethyan Himalaya. You do notice a change in the topography from the sheer steep slopes and narrow valleys typical of the Greater Himalaya to the wider valley forms and gentler gradients of the Tethyan domain. 

The Goriganga at Rilkot. The river is more serene here making a soothing gurgling sound as it flow past. Also check out the gorgeous longitudinal gravel bars in the river channel. Permanent Link: Goriganga at Rilkot.  

The high meadows of Martoli. This is a beautiful if desolate place with stunning views of the high Himalayan all around. 

A lone resident of Burfu surveys his kingdom. Most of the villages were empty of people as residents had migrated to lower altitudes for the winter. The flat plateau seen in the background is a glacial outwash terrace. It was formed by streams redepositing debris that accumulates in front of a glacier. Thick layered river deposits create a plain in front of the glacier. At a later point in time, the river cut through its own deposits, forming flat terraces stranded high on the valley slopes. 

Encounter on a lonely trail. After walking alone for hours, it is always fun to meet the locals travelling between villages. We met this small caravan between the settlements of Burfu and Bilju. Permanent link: Encounter at Bilju.

 A house in Milam village basks in the October sun. 

The Goriganga snakes its way down Milam Glacier through the fabled Johar Valley. This location is a few kilometers downstream of the glacier. 

Near Milam Glacier! The actual glacier is about 4-5 km upstream of this location, but this is a good photo spot along the trail.

What a trip! I think late September to early October is really the best time to visit this area. The countryside is lush and you get clear views of the Himalaya. The local residents have still not migrated to lower altitudes and you can get to enjoy their company in the many hamlets along the way. However, this year, rains continued well into the second week of October. I feel with climate change there will be a greater unpredictability to October weather in the future.

Finally, a big thank  you to Emmanuel Theophilus, Malika, Kamala Pandey, and Munna Singh Nitwal for being such gracious hosts and making my trip so memorable.

A post on geology tips for trekkers is coming soon... 

Field Photos: Italy Swiss Alps

A friend recently went for a trek to the Italian and Swiss Alps and sent me these stunning photos.

All Alps pics by Dr. Sushma Date.

A view along the Santa Magdalena or the Alp Suisse trail.

Imposing Pinnacles along the Tre Cime di Lavaredo hike in the Italian Alps.

 A close up of limestones and dolomites in the Italian Alps.

 A panoramic view of the distinctive landscape along the trail.

There is so much to see here in terms of geomorphology and how glacial erosion throughout the Quaternary Period has carved out the terrain. But my friend was also walking past rock outcrops that stand witness to one of the most enduring debates in sedimentary geology: the origin of that distinctive layering in these sediments.

The section of the Alps my friend was trekking in is made  up of Middle to Late Triassic age (225 -200 million years ago) limestones and dolomites. They formed in the warm tropical waters of the western Tethys Ocean. A closer examination of the layering reveals that the sediments were deposited in two broad subenvironments of a shallow sea, the intertidal zone and the subtidal zone. Intertidal and subtidal sediments alternate to form a depositional pulse or a cycle. Such couplets are stacked to form the thousands of feet of strata observed in this part of the Alps.

What could be causing the alternation of the intertidal and subtidal environments? Thick intervals of these Triassic deposits are made up tidal mud flats overlain by restricted lagoon sediments, or tidal mud flat overlain by open circulation subtidal environments, or lagoon deposits overlain by mud flats. When beds are traced laterally, these same environments grade into each other. Such inter-fingering arrangements suggest that environment adjacent to each other migrate, resulting in a vertical succession of alternating sediment types.  

Geologists recognize that such changes can be 'áutocyclic', driven by mechanisms internal to the sedimentary basin. A site of biological productivity and sediment production may choke itself by overproducing sediment. The loci of sediment production may shift to a more favorable site. Episodic storms keep redistributing sediment and reorganizing current directions . Such feedbacks result in similar environments appearing and disappearing from any one location, resulting in a cyclic sedimentary record. 

There are also successions of strata in the Triassic Alps which show a very different arrangement of sediment types. In this variation of cyclicity, intertidal mud flats may be overlain by relatively deeper water subtidal sediments which in turn are overlain by a red soil layer. The formation of soil on top of subtidal sediments deposited in water depths of up to 10 meters or so indicates a substantial drop in sea level. The top of the exposed subtidal layer was then chemically weathered to form a soil. 

Autocylic shifts in environments are gentle nudges which push one environment over another. They can't generate such a big drop in sea level. There must be drivers external to this environment that may cause sea level to rise and fall at regular intervals. These external agencies or  'allocyclic' mechanisms have been invoked to explain parts of these Triassic sequences. 

What could be controlling the regular rise and fall in sea level? Long term (over millions of years) tectonic subsidence of the basin floor certainly would have created the accommodation space for the accumulation of sediment. However, geologists look toward a different mechanism to explain the repeated deepening and shallowing events observed in these Triassic strata. 

Climate change can cause regular shifts in sea level. During the past 2.6 million years of the Quaternary ice age, sea levels have fallen by as much as 100 meters during phases of continental glacier growth, and risen during inter-glacial times when ice sheets melt. These changes have taken place at intervals of 400,000 years in the early part of the Quaternary, changing to beats of 100,000 years over the past million years. Sea level changes due to growth and decay of continental glaciers are termed glacio-eustacy. Unlike autocycles which can have variable time spans, there is a fixed periodicity to these climate driven allocycles. 

We now know that these climate cycles are controlled by periodic changes in the earth's orbital parameters which cause cyclic variation in the amount of incoming solar radiation. Such Milankovic glacio-eustatic cycles, named after the Serbian mathematician who worked out the details of earth's orbital behavior, have been recognized during other times of widespread glaciation such as the Permian. 

Milankovic worked out that there are three types of orbital movements that affect how much solar radiation reaches the top of earth's atmosphere. The shape of the earth's orbit or eccentricity cyclically varies with a period of 100,000 years and with a longer period of 400,000 years. Obliquity, or the tilt of the earth's axis with respect to its orbital plane, changes every 40,000 years. The third type are Precession cycles of 26,000 years. This is the wobble or the direction the earth's axis points to.

The Triassic though was a very hot world! The earth's land masses, amalgamated in the supercontinent Pangaea, were situated across the equator. There were no continental glaciers to wax and wane and drive sea level change. Glacio-eustacy is not a workable explanation for these cyclic Alpine sedimentary sequences.

Of late many geologists have started pointing to groundwater storage in continental aquifers as a means of causing periodic sea level change. It does sound like a fantastical idea! Such groundwater mediated sea level changes go by the name of aquifer eustacy. Milankovic climate cycles may not trigger glaciation during hot earth periods. But they can modulate long lasting humid and arid phases, each lasting tens of thousands of years. Sea levels are lowered during hot humid phases as oceans lose water by evaporation while continental aquifers get recharged. During arid phases, water is lost from aquifers by evapo-transpiration and discharge, resulting in a rise in sea level. 

An inverse phase relationship between groundwater level and sea level is thus an expectation of aquifer eustacy.

There is enough water in continental aquifers to modulate sea level change of several meters. Here is an impressive statistic. There is approximately 25 million cubic kilometer of pore space in the upper 1 km of continents above sea level.  If this is completely filled with water, the amount will equal the volume of water in continental ice caps. Even a small fraction of these pore spaces actually getting filled with water or emptying of it can change sea levels by several meters. 

Recent short term measurements of the hydrological cycle supports the notion that groundwater storage can influence sea level. For example, very high rainfall over Australia and part of the southern Hemisphere in 2011 resulted in a drop of 7 mm in global sea level that lasted a few months. And the Gravity Recovery and Climate Experiment satellite data since 2002 indicates that increased land water storage has actually slowed down the rate of sea level rise by a small amount.

Can some of the Triassic sedimentary cycles of the Alps be attributed to aquifer eustacy? How can one track periodic groundwater change in geologic history and test whether they coincide with sea level changes? One proxy is to use lake sediments of the same age as marine sequences.  Lakes are connected to aquifers.  High lake levels are indicators of saturated aquifers. Lake levels drop as aquifers discharge. Geologists have been studying Late Triassic age lake sediments from the Newark Basin in  northeastern U.S. They have identified sedimentary cycles formed during alternating humid (high lake levels) and arid climate (low lake levels) phases. 

The broad time span of these lake sequences coincide with the time frame of some thick intervals of marine sedimentary cycles of the Alps. Whether individual lake and marine cycles are out of phase could not be worked out due to limitations in age resolution of strata. However, a Milankovic band 400,000 year periodicity has been estimated for these cycles, a finding strongly suggestive of  climate driven eustacy.  From another time period, some analysis of  Cretaceous age lake sediments of Songliao Basin of NE China indicated lake level highs coinciding with global sea level lows. This finding also hints that aquifer recharge and discharge may be primarily responsible for periodic sea level changes during a greenhouse earth when there are no continental glaciers to modulate sea levels. 

Such questions continue to be asked and the mechanisms behind generating sedimentary cycles of the Triassic has by no means been satisfactorily worked out. There are many types of cycles in the Triassic Alps, observed R.A. Fischer, whose seminal work in the 1960's opened up avenues of debate that continue unabated. Perhaps it is the spectacular setting and stark rock faces that lend themselves to bold hypothesis making, linking sedimentary rhythms to the celestial dance of our planet.  

Landscapes - Gogina To Munsiyari

I just finished a fabulous trek in the Kumaon Himalaya, Uttarakhand. We started from Gogina village. The route took us to Namik, then northwards along some high ridges towards Sudamkhan Pass. The plan was to turn eastwards at Sudamkhan Pass and walk along a high shepherd's trail towards Khaliya high ridges, and then descend towards Munsiyari. But some very nasty weather forced us to turn back from Sudamkhan. We then took a lower altitude route southeastwards, and after a few days walk ended up just near Birthi Falls roadhead. A taxi picked us there and took us on an hour long drive to the town of Munsiyari.

The map below shows the location of Gogina, Namik, Birthi and Munisyari.



We climbed from around 5000 ft starting at Gogina to a maximum of around 12, 500 feet near the Sudamkhan area. After Namik there was no village until  we reached Birthi, and so we passed through some glorious isolated wilderness areas, ascending from temperature broadleaf forests to alpine tundra like environs made up of grasslands and meadows and up to more bare rocky heights.

The terrain is made up of medium to high grade metamorphic rocks of the Greater Himalaya Sequence. I noticed amphibolites, mica, garnet and feldspar gnessises, mica schists, phyllites, calc silicates (metamorphosed clay bearing limestones) along the way. However, the pace of the trek required me to keep walking along with my friends... so I did not do much geology on this trek.

Below are some pictures I took during the trek.

1) A view of the Lesser Himalaya from Gyan Dhura village (before we reached Gogina).

2) A house in Namik Village

3) So many geological stories written in to the lovely building stones of Namik Village

4) We climbed above Namik Village and set up camp in this lovely meadow.

5) Walking through a lush forest above Namik

6) Above the tree line, a trail leads to a shepherd's lonely outpost.. route towards Sudamkhan Pass.

7) The desolate yet hauntingly beautiful landscape near Sudamkhan Pass.

8) That's me, taking in the stunning surroundings near Sudamkhan Pass.

9) Gneisses of the Greater Himalaya Sequence exposed along the high bare ridges.

10) At Bajemania meadows after we descended from the Sudamkhan area. Watching an afternoon storm build up in a distance.

11) Our pack horses enjoying a meal as fresh snow cover the higher slopes.

12) Autumn colors glow in the late evening sun.

13) The majestic Panchachuli Range at sunset. View from Munsiyari.

.. with promises to keep traveling in the Himalaya.