Press release: Moraines and eroded mountains: Testimony to a continental glacier

Nr. 270/2014 - 14.11.2014

Göttingen geomorphologist proves Ice Age glacier cover in Central Tibet for the first time

(pug) For the first time, a foreign geoscientist has succeeded in travelling to one of the most far-reaching areas of Central Tibet to study the evolution of Ice Age landscapes. "The geomorphological findings in the region southwest to northwest of the Purog Kangri Massif give testimony to complete continental glaciation," states Professor Matthias Kuhle of Göttingen University's Institute of Geography. What is so special about the expedition approved by the Chinese government after 24 years is that the geoscientists were allowed to extract samples from this immensely rugged and uninhabited natural reserve and take them to Germany for analysis.

"On expeditions spanning a total of 40 years, I have explored virtually every corner of Tibet and finally been able to demonstrate Ice Age glacier cover," states Professor Kuhle. A glacier cover can be proved based on moraines, erratics (like findings of basalt deposits), smoothly rounded mountains as well as when a mixture composed of various rock types is present. The discussion has been raging for decades as to whether the centre of Tibet was covered by colossal ice sheets or was glacier-free during the last Ice Age around 20,000 to 60,000 years ago.

The expedition posed a monumental challenge itself: "There are neither streets nor paths nor villages in this territory," recounts Professor Kuhle. "In the summer, the surface of the permafrost soil softens. This deep layer of mud is unnavigable, even with the most robust off-road vehicles. With the snow-drifts in winter, it's inconceivable to even consider passing through there either. This basically uncharted territory is only accessible between September and October under favourable weather conditions. That is the time window we used." Professor Kuhle was accompanied by a team of 10 mountaineers on his five-and-a-half long week expedition.

Tibet's relevance to Ice Age research is that it encompasses no less than 2.4 million square kilometres of continental ice mass. "About a million years ago, plate tectonics shifted Tibet – actually located in the subtropics – up to above the snowline, causing glaciation of the highlands to occur. Covered by glacial ice, Tibet became the world's largest cooling surface: Around 75 percent of the high subtropical inward radiation was reflected off its glacial surface into space. Because this reflection took place directly, short-wave sunlight could not be converted into long-wave thermal radiation and heat up the atmosphere. The global loss of energy caused by this was a trigger for the Ice Age," Professor Kuhle explains.

Ice Age research studies the greatest climate change in the history of mankind against the backdrop of the ongoing discussion about global warming – currently around one degree Celsius on average: "The average temperatures during the last Ice Age were around ten degrees lower than those we experience nowadays.”

Contact address:
Professor Matthias Kuhle, PhD
Georg-August-Universität Göttingen
Faculty of Geoscience and Geography
Institute of Geography
Department of Geography and High Mountain Geomorphology
Goldschmidtstrasse 5, 37077 Göttingen
Phone +49 (0)551 39-8067
E-mail: mkuhle@gwdg.de
Website: www.uni-goettingen.de/de/409944.html