iTECC in the Himalaya
You know, as geologists, we have many types of fancy machines and complicated models that we use to solve complex problems about the Earth, planets and solar system that we live in. But sometimes, that is not enough, and we have to actually leave the comforts of home and go out into the field to see the rocks and geology that we are understanding to gain a better perspective on the problems we are trying to solve and also just to see some amazing landscapes. As geologist Phillip H. Kuenen once said, "Experimental geology has this in common with all other branches of our science, petrology and palaeontology included, that in the long run it withers indoors." So, in that spirit, the iTECC set out for the Himalaya in mid-October of this year for a three week trip from Kathmandu all the way to Jomson.
After our arrival in Kathamndu, the iTECC group met up at the Yellow Pagoda Hotel. And after some sightseeing around the city, we had a debrief about the logistics of the trip and especially the insurance due to a large, tragic avalanche that occured in one of the passes of the High Himlaya just a few days before our arrival. The next day everyone was up early and ready for an 8 hour bus ride from Kathmandu (at 1300 meters) to Butwal (at 365 meters). Driving out of the Kathmandu Valley you are exposed to miles and miles of lacustrine deposits. And after a hike up the last small pass, it is down, down, down along long stretches of gneiss outcrop and quite a scary drive along a road that is apparently the only way to go from Kathmandu to India.
We spent two days in Butwal taking a look at the Siwalik Group of Nepal. This rock formation represents a 15.8-1 million year old river sediment sequence. The Lower Siwaliks contain sandstones along with oxidized paleosols (), the Middle Siwaliks consist of thick sandstones and histosols and the Upper Siwaliks consist of gravelly braided stream deposits. These sediments are basically everything that has been eroded from the Higher Himalaya over the past 20 million years. The bus dropped off at Surai Khola and we started walking back toward Butwal documenting all of the interesting features in the Siwaliks that we saw along the way.
The next day we were back on the bus early and on our way to the tourist center of Nepal: Pokhara! Along the way we stopped and hiked down to a stream to check out an interesting oxisol, which some geologists believe marks a basin wide unconformity. From here, we entered the Pokhara basin and saw our first impeccable views of the Annapurna Massif and some impressive successions of lake and fluvial terraces.
A little bit higher we entered the Lesser Himalayan Group proper. Despite a large amount of work on these rocks, the research groups that have worked here have each come up with their own names for each type of rock and group of rocks. Thus, for the same rock sequence, there exists multiple names based upon which paper is read. In general, there are two major groups of rocks in the Lesser Himalaya : (1) A lower unit composed of sandstones and volcanic sediments with a small area of granite that has been metamorphosed to orthogneiss and (2) a higher unit composed of schists, limestones and dolomites.
The next day, from Pokhara, we took our last bus ride for about an hour and disembarked at a small trail village called Nayapul. From there, our guides strapped our luggage to some very lovely trail horses and we strapped on our backpacks for the 1030 meter climb up to Ulleri.
This is the first time we see the famous Nepali porters. The loads are too large for any human to ethically carry; the weight, perhaps 100 pounds (45 kilos) or more, carried by a band around the forehead. The porters’ clothes are soiled with dirt. Their t-shirts soaked with sweat. And their shoes unfit even for a walk down the street. Talking with our guide Babulal, he says that tour agencies often exploit and abuse porters, who are largely uneducated and have no other employment options. He also tells me the men are probably happy to have work. They are paid around $8 US/day for their Herculean efforts.
At lunch, we stopped at a small village, and our guide Babula pointed out a small ridge way up on the next mountain. ‘That’s where we stay tonight,’ he told us much to our chagrin. Roughly two hours after lunch and 3200 grueling stone steps later, we arrive in Ulleri, an ancient village of stone houses sitting above terraced farmland and drop-off cliffs. The snow-capped mountain of Annapurna South (7,219 m) is in the distance. The geology that day was quite impressive with views of phyllites, many different types of schists and some augen gneiss. However, the difficulty and longevity of the climb boiled the last part of the day’s hike down to surviving and checking out the beautiful views every once in a while.
From Ulleri, we weren’t saved from the climbing yet. We still had another 800 meters of steps and uphill to go to Ghorepani. Along the way, we saw a number of phyllites, schists and quartzites. The high grade of metamorphism that is exhibited in these rocks gives support to the proximity of the Main Central Thrust (MCT) being near this area.
After waking up entirely to early, we hoofed it up Poon Hill to check out the amazing views. Unfortunately, the clouds blocked a little of what was still a breathtaking outlook. I’d, however, reccomend doing this when it is known that there will be not a lot of tourists/trekkers doing the same thing as you. It became quite crowded.
From Ghorepani to Tatopani, it is a long, long way down…about 2000 meters to be exact. Along the way, we saw more of the Lesser Himalayan amphibolites, quartzites, phylittes and some beautiful examples of folding. Tatopani is another popular tourist destination along the raging Kali Gandaki River. Tatopani literally means ‘hot water.’ There are two popular hot springs near the Kali Gandaki that are very nice and relaxing after a long day’s hike.
The next day, we mainly traveled the 1290 meters uphill by bus, which was, in the very least, quite a terrifying ride, with drops of greater than 1000 meters off the side of the road at times. However, the bus ride offered the chance to see two large rockslides/debris flows: (1) the large prehistoric Dhampu-Chhoya rockslide, which has blocked the Kali Gandaki and subsequently formed a large lake and (2) the catastrophic debris flow coming off the northern slopes of the Nilgiri and Tilicho peaks. These rare, large events play a key role in shaping the Himalaya, but the more frequent, medium-sized events are much more of a concern to Nepali villagers. Along the way, we also entered the High Himalayan Crystalline (HHC) series proper above the Main Central Thrust (MCT). With the increasing metamorphic grade of rocks in the HHC, we began to see evidence of this increase in the minerals that we could pick out while looking at the rocks with a hand-lens. Minerals such as garnet, staurolite and kyanite.
From Lete, it was a 14 kilometer hike along the Kali Gandaki, but thankfully a relative flat one. Our goal of the day was to spot the ever-elusive South Tibetan Detachment System (STDS). This is the boundary between the HHC metamorphic rocks and the Tethyan Sedimentary Series (TSS). It is ‘elusive’ because the STDS has actually never been found. Geologists in the 1980s placed this boundary at the Chhaktan Khola, but there is no evidence of this here as the metamorphic rocks of the HHC are seen to intrude into the TSS sedimentary rocks, thus not producing a clear boundary.
Along the way, we came across a Tibetan monastery and behind and the rest of the way to Tukche, clusters of Tibetan refugee camps. It was quite amazing to actually see these camps and the people after only hearing these events that took place for so long.
After a night in the lovely village of Tukche (which is fun to say), we packed up our gear and headed to our final destination 13 kilometers away, Jomsom. Now in the TSS proper, it was back to sediments, such as limestones, shales and some lower grade meta-sedimentary rocks. These sediments came from in between India and Asia, in the so-called Tethys Ocean. As India barreled toward Asia, these sediments were continually scraped and piled on top. And although they can be seen at relatively low elevation where we were, these are the famous sediments that compose the high peaks of the Himalaya, such as Mt. Everest.
The transition along the way from Tukche to Jomsom was quite impressive. I mean to say that we walked from an area of relatively high year round precipitation into the rain shadow of the Himalaya with very, very little annual precipitation. And the landscape completely changed, reminding me of the mountains and desert of southern California.
With two days to spend in Jomsom, we settled in and got comfortable. And appropriately, our last day on the trail was to be our highest in elevation. Up early, we took a jeep/bus ride 18 kilometers and up 1020 meters to Muktinath. Muktinath village is situated at 3700 meters. The village is named after the holy temple of Muktinath situated at the highest part of the village. One of the most interesting aspects of the Muktinath temple is the seepage of methane gas from the moraine sediments below the temple, which feeds a continuously burning flame inside the temple at Muktinath.
From Muktinath, we hiked down a bit and then back up a steep climb to a little above 4000 meters, taking a try to spot the STDS along the way, which can be clearly seen on the higher peaks. After a long hike down and lunch we made it back across the Kali Gandaki floodplain to Jomsom, high winds at our backs pushing us along.
Take a look at the pictures attached this blog post as well as the pictures posted on our Facebook page!