ML Verma/ Shimla, Sep 30
The Himalayas considered the youngest mountain ranges of the world, are slowly unfolding as a treasure house for paleontologists as geoheritage sites are being located along various dried and existing lakes, sedimentary deposits by the experts recently. As we know that the Himalayas is the mountain in making due to Eurasian tectonic plates thrust and reminiscent of Eurasia exists in regions like Ladakh, Leh, and Lahaul Spiti. This natural Geo-activities phenomenon is confirmed and established by noting the increasing height of Mountain Everest. The new height of the summit has recently been recorded as 8,848.86m (29,032 ft) which is 0.86 meters or 86 cm more than previously measured 8848 m.
The presence of Eurasia is also being confirmed by the presence of saline water of Pangong lake and other deposits as Rock Salt being found in the Himalayas. Darang area has a massive deposit of Rocksalt in the Mandi district of Himachal Pradesh.
We had reported earlier that concerned archeological authorities have imposed precautionary restrictions on the anthropogenic activities and started vigil along with all such places where links were established during studies by paleontologists and archeologists in recent times.
A recent study established by the Geo-Archeological experts now presents a new unexplored dimension that number of lakes which have been ruined down in history or are present even today reveal similar strong link of the bygone era.
These experts inform that Lakes of present and past in Ladakh have fascinated the human since time immemorial and these lakes played an important role for traders on the old silk route.
“If we say Leh and surrounding areas was a city of Lakes thousand years ago which were more beautiful and extravagant then the present lakes of Pangong and Tsomo-rari, there will be no exaggeration”, claimed Dr. Ritesh Arya of Indian Geoparks and his team comprising of Mohamad Iliyas and Kunzang Dolma of Ladakh Science Foundation who has been researching on these lake sediments.
The basis of their claim is the presence of freshwater fossils of molluscs and plants found in the paleolake deposits which were earlier considered devoid of any life.
First report of fossils from paleolake deposits
This is the 1st report of fossils from the paleolake deposits. Dr. Arya informed that these fossils were found when they were doing a detailed investigation for the reconstruction of events for the formation and development of the paleolake at Shey in Ladakh. The story started when a group of about 30 students from Ladakh Science Foundation approached Dr. Ritesh Arya to explain the presence of the Lake and the appearance of mud cracks on the surface of the raised structure in Shey.
The stupas in Shey had fascinated everyone and Dr. Arya Guinness World Record holder was no exception the question of so many stupas had been intriguing him for long. After some observations, he thought that there was a relationship between Stupas and Lake. He discussed the matter with Tashi of Ladakh Science Foundation and both agreed to work on the project to find the truth.
Preliminary investigations displayed that there was a relationship between the Stupas and the floods. Everyone got interested and after a detailed study, a particular pattern was observed in the manner the stupas were placed, informed Arya. They were a perfect mechanism of defense from floods to Shey village which was strategically important as it was the 1st palace in Leh built in the 10th century.
After detailed investigations for the first time showed discovery of the existence of life in the form of fossils of a plant (with hollow stems very well preserved in the multiple beds) and freshwater molluscs in the lacustrine deposits (at an altitude of 3000mtrs above mean sea level) in the cold mountain deserts of Ladakh. These findings were presented in the International Webinar on Molluscs and Ancient Human Societies & Meeting of AMWG. 28-30th September 2021.
The network of the roots of plants with nodules formed at their tips are also very well preserved showing an adaptive mechanism of plants to help them float in the lakes, these hydrophylls with their adaptive mechanism if analyzed can help in understanding the morphological changes these plants have undergone to survive in the extreme conditions, added the geologist.
Identification of these fossils will help in paleoenvironmental reconstruction and understanding the paleo-climatic changes. “Samples have been sent for investigation to Director Birbal Sahni Institute of paleosciences Lucknow,” he added. Precise dating of the organic matter preserved will help in calculating the actual age of the lake sediments and the changes it has undergone in geological time.
These findings will help in understanding the cyclicity of global warming and cooling which will play important role in establishing the climate change event since the last ice age around 11717years from the present day.
Particular pattern of orientation of Stupas an effective mechanism for defense against flash floods
Various geological events leading to the formation of the boundary of the lake during cooling times, the formation of the lake after the advent of warming conditions, when glaciers started receding, leading to the development of the Lake with recharging from glacial melts.
This was followed by flooding which brought material from Matho across the Indus river momentarily blocking river Indus and later breaching the wall of the lake in the past which led to a sudden influx of sediments and finally raising of its levels. Shreds of evidence of flooding from Stagmo are also recorded in the section. This caused a lot of damage to the Shey village. In response to this many Stupas and walls were build in Shey to protect the village and lake downstream.
On careful observation, a particular pattern of the orientation of Stupas was found which was an effective mechanism for defense against flash floods from Stagmo glacial melt.
But unprecedented landslides and mud creep caused by cloud burst brought a lot of debris from the Northern and Northwestern part of Ladakh batholith all these activities in the past further reduced the Lake into the pond, he stated. But this time these walls were made of clay from the pond and not of the stones.
These Stupas were more ornamental and ritual and today are in a much-degraded condition than stupas build in earlier times.
Evidence of convolutions formed due to frost action is also very well preserved. In the top section evidence of seismic events is visible showing paleo-seismic activity in the past.
But pieces of evidence of what ultimately caused the death of the lake were still unknown? Then the answer came when the surface of the pond was examined. The answer was simple drying of the pond in the lake because the Stagmo glacier in the past receded and failed to feed the pond and the lake died.
Dr. Arya says the present site which holds these pieces of evidence of climate change, fossils, flash floods, etc needs preservation & conservation and should be declared as a Geoheritage site of great importance as these sections hold the key to understand the changes in climate and response of humans to this and changes site has undergone in the past.
This also shows how during the lama rule engineers planned to tackle climate changes using natural resources. All this detailed study will help in conservation and boost geo-tourism in this part of the Himalayas, expert says continuing their exploration in the region.