Pang-la Pass and Chomolungma


Village on North Side of Pangla Pass - J.H. Wittke

 

We bounce up a rough road to Pangla Pass, fording a river and speeding through muddy farm fields. We leave the main highway and pass through a small Tibetan village (left).


Folds on north side of Pangla Pass - J.H. Wittke

 

As we drive up a series of switchbacks up to Pang-la Pass (5200 m), we can see spectacular exposures of faulted and folded forearc sediments from our precarious seats in the rear of the truck (left).


Post at Pang-la Pass - J.H. Wittke

 

The top of Pang-la Pass is marked by a cairn with a pole stuck in its center from which hang strings of prayer flags. The base of the cairn is piled with offerings of stones and bones. Nearby is a low concrete monument with a plaque identifying the mountain peaks, which protrude through a blanket of cloud to the south: Makalu (8463 m), Lhotse (8516 m), Chomolungma (8848 m), and Cho Oyu (8201 m). Beside it is a square post covered by aluminum plates with the words "May Peace Prevail on Earth" written in four languages: Tibetan, English, Japanese, and Chinese (left) Someone has scratched over the Chinese and scribed "Free Tibet" into the soft metal.


Chomolungma from Pangla Pass - J.H. Wittke

From Pangla Pass we can see the famous North Face and Northeast Ridge of Mt. Everest (right), the site of the first attempts to climb the Earth's tallest peak. On 8 June 1924, the legendary British climber George Mallory ("Because it's there.") and Andrew Irvine disappeared on the Northeast Ridge during their bid to reach the summit. They were last spotted by Noel Odell, the first geologist on Everest, above a rock outcropping called the "Second Step," which is about 375 m beneath the summit. Odell described them as "going strong," and debate continues to rage whether they reached the summit only to die during their return. It was not until 29 May 1953, that Sir Edmund Hillary and Tenzing Norgay made the first generally recognized ascent. Mallory's body was discovered by a 1999 NOVA-sponsored expedition to the North Face of Everest. There's more about Mt. Everest at http://www.peakware.com/encyclopedia/peaks/everest.htm and http://www.nationalgeographic.com/everest.

The South Tibetan detachment fault crops out beneath the thick Ordovician carbonate beds that form Chomolungma's summit pyramid. This northward-dipping low-angle fault was only recognized in the past decade. It juxtaposes low-grade lower Paleozoic metasedimentary rocks and the high-grade metamorphic rocks of the Greater Himalayas. As the Himalayan Mountains grew, they became gravitationally unstable and their height was reduced by northward movement along listric extensional faults such as the South Tibetan Detachment. The detachment has been dated as Miocene (c. 20 Ma) and demonstrates that extension can occur simultaneously with compression in an orogenic belt.

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