Fedchenko Glacier (Tajikistan): Alpine Glacier
1. Zoom from Antarctica to Fedchenko Glacier (Tajikistan)
2. In lecture 7 we focused on the most impressive mountains in the world, the
Himalayas. But if you travel around to the west end of the Himalayan plateau,
there are some mountain ranges that would be the star of any other planet
a. These are the Karakoram, Kunlun, Pamir, and Tien Shan mountains in
a land-locked part of the world that most people don’t know very
much about. It sits at the intersection of China, India, Pakistan,
Afghanistan, Kazakhstan, Kyrgyzstan, Uzbekistan, and Tajikistan)
b. The greatest concentration of 8000 ft mountains is found here (K2 in
the Karakoram Mtns is only 237 m lower than Mt. Everest)
c. The world’s longest alpine glaciers are also found here, and prince
among them is the Fedchenko glacier, 77 km long, in Tajikistan in the
Pamir Mtns.
3. A word of clarification is needed here. In the last lecture, on Antarctica, we
saw the world’s longest glacier, the Lambert Glacier, which was more than
400 km long and 100 km wide in places. This is a massive ice stream. For
Antarctica and Greenland, which are covered with ice that flows out in all
directions, the glaciers are massive in length and width. These are
continental glaciers.
a. For the rest of the world, glaciers operate differently. They snake
between and around tall mountain peaks, eroding away the
mountains over time. These are called alpine glaciers. Less ice, but
more varied and unusual in how they operate.
4. Alpine glaciers are very much like rivers of liquid water. They move much
slower, of course, but they may end up moving even more rock.
a. Giant conveyor belts, tearing down mountains.
b. “Nature hates mountains,” and glaciers are the mechanism it uses to
demonstrate that.
c. Tend to start small at the highest locations and become larger as they
flow downhill  system of tributaries.
d. Ice is solid (it is technically a mineral), but it flows (faster in the
middle of the glacier, slower along the bottom and sides)
e. But the glacier also slides along the bottom.
i. Glacial plucking; striations
ii. When it speeds up  crevasses
f. Though the glacier is made of ice, it is often not white  all the rock in
it!
i. Zones of accumulation/ablation; snow line
ii. Explain medial moraines.
iii. Frost wedging causes rockfalls onto the top of the glacier
iv. Explain terminal moraines
v. When glacier front is stationary (though glacier is still
flowing!), all the rock gets dumped in one place.
vi. If climate is changing and the glacier front is retreating or
advancing, the sediment is spread out over time.
vii. Melting ice carries the sediment downstream in sedimentclogged braided streams (we saw this in the lecture on the
Ganges Delta).
viii. Sub-glacial streams move sediment too.
5. The Pamir Mountains, where the Fedchenko Glacier is, have a long history.
a. “Pamir” means a broad flat valley, carved by a large ice sheet,
surrounded by mountains. [show picture of the Great Pamir – border
of Tajikistan and Afghanistan]
b. Trade with the middle east for thousands of years
i. Trade routes described by Ptolemy
ii. Lapis Lazuli in Egyptian tombs is from here
iii. The Silk Route went through the Pamirs; because of its
strategic position it has been the subject of many wars for
control
iv. Recently, discoveries of great mineral wealth in the
surrounding areas (Ex/ Afghanistan might have the largest
reserve of lithium (for batteries!!))
c. Still, it is a very remote area. The Fedchenko Glacier wasn’t fully
explored until 1928, by a joint German/Russian expedition led by
Willi Rickmers (named after Alexei Fedchenko, a famous Russion
explorer and naturalist of the 1800s).
6. The Fedchenko Glacier starts high up, starting at over 20,000 feet, and comes
down more than 10,000 ft in elevation to the Balandkiik River.
a. It is narrow, only about 3 km wide at the most, and 1 km thick at the
most.
b. Still, with its tributaries, it has about 35 mi3 of ice – about 1/3 the size
of Lake Erie.
c. When you look, you can see many stripes running down the length of
it – from all the tributaries combining together.
i. Many of these used to be separate glaciers, with their own
terminations, but the Fedchencko pirated them and became a
single large tree-shaped pattern.
d. Dumps its sediment at the Balandkiik River.
7. But the moraine at the end shows that the front of the glacier has been
rapidly receding over the past century. [show figure]
a. This is a trend seen around the world [show graph and map]
b. In the case of the Fedchenko Glacier, this is also associated with a
transition to a drier climate.
c. The water from the Fedchenko eventually flows west to Uzbekistan
and into the Aral Sea. But a combination of human use of water and
decrease in rainfall has made the Aral Sea practically disappear [show
then and now]. Disaster for the economy of the region. Once had
active fishing industry.
i. Aral Sea was the world’s 4th largest lake in 1960.
ii. Now almost nothing – like completely draining both Lake Erie
and Ontario.
d. Climate change has been the rule on the planet, long before people
were around. There have been times when nearly the whole planet
has been covered with ice. And times when there was hardly any at
all. It was a warming period 2500 years ago that melted the mountain
passes in places like the Pamir Range and opened up the Silk Route for
trade. This warming was good for some peoples, and bad for others.
We are in another such warming trend. People up in the mountains of
the Himalayas will find it a slightly nicer place to live. But people
down in arid regions will have a rougher time of it.
8. Top 5:
a. Siachen Glacier (Karakoram Mts., India) – second longest at 70 km
b. Bruggen Glacier (Chile) – 3rd longest at 64 km
c. Biafo Glacier (Karakoram Mtns, Pakistan) – 4rd longest at 63 km
d. Inylchek Glacier (Tien Shan Mtns, Kyrgyzstan) - 5th longest at 62 km.
Questions:
1) How are the Pamir Mountains related to the Himalayas?
2) Long Island, NY, is a glacial moraine that formed during the Ice Ages, as ice
flowed down from Canada, carrying rock within it. Why do you think Long
Island sits south of the Connecticut coast?