Ledoyom ( rus, ледоём, p=lʲɪdɐˈjom) is a term proposed by the Russian geologist for

intermontane Intermontane is a physiographic adjective formed from the prefix " inter-" (''signifying among, between, amid, during, within, mutual, reciprocal'') and the adjective "montane" (inhabiting, or growing in mountainous regions, especially cool, mo ...

depressions which might get completely filled by

glaciers A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

from the surrounding mountains at the maxima of

glaciation A glacial period (alternatively glacial or glaciation) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate be ...

Etymology

The Russian term “''Ledoyom'' (ледоём)” means “body of ice” by analogy with a “body of water” ("vodoyom").''Rudoy A.N.'' Mountain Ice-Dammed Lakes of Southern

Siberia Siberia ( ; , ) is an extensive geographical region comprising all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has formed a part of the sovereign territory of Russia and its predecessor states ...

and their Influence on the Development and Regime of the Runoff Systems of

North Asia North Asia or Northern Asia () is the northern region of Asia, which is defined in geography, geographical terms and consists of three federal districts of Russia: Ural Federal District, Ural, Siberian Federal District, Siberian, and the Far E ...

in the

Late Pleistocene The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as the Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division ...

. Chapter 16. — In: Palaeohydrology and Environmental Change / Eds: G. Benito, V.R. Baker, K.J. Gregory. — Chichester: John Wiley & Sons Ltd., 1998. — P. 215–234.

Description

In the 1930s the Russian geologist V.P. Nekhoroshev marked out intermontane depressions in the Altai which might get completely filled by glaciers from the surrounding mountains at the maxima of glaciation. He called such depressions "ledoyoms". Ledoyoms produced large valley

glacier A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires ...

s within outlet runoff valleys from the depressions at culmination stages of their development. Diagnostic marks of the so-called classical ledoyoms are

moraine A moraine is any accumulation of unconsolidated debris (regolith and Rock (geology), rock), sometimes referred to as glacial till, that occurs in both currently and formerly glaciated regions, and that has been previously carried along by a gla ...

esker An esker, eskar, eschar, or os, sometimes called an ''asar'', ''osar'', or ''serpent kame'', is a long, winding ridge of stratified sand and gravel, examples of which occur in glaciated and formerly glaciated regions of Europe and North Amer ...

s and

kame A kame, or ''knob'', is a glacial landform, an irregularly shaped hill or mound composed of sand, gravel and till that accumulates in a depression on a retreating glacier, and is then deposited on the land surface with further melting of the g ...

s on the bottoms of the corresponding depressions. In the 1980s and 1990s the development of the idea by Russian geologist of glacier-dammed lakes which used to fill most of the inter-montane basins of the mountain belt of

, the depressions of Teletskoye and

Baikal Lake Baikal is a rift lake and the deepest lake in the world. It is situated in southern Siberia, Russia between the federal subjects of Irkutsk Oblast to the northwest and the Republic of Buryatia to the southeast. At —slightly larger tha ...

lakes including, took place. It also became clear that many depressions, even very large ones, had been already occupied by dammed water basins by the time when the glaciers of the mountain frame moved forward into them. Thus, mountain glaciers turned into original “ shelf” glaciers and armored completely the surface of the glacier-dammed lake joining together floating on the surface. That is the way the so-called “captured lakes” came to exist. At maximum lowering of the

snow-line The climatic snow line is the boundary between a snow-covered and snow-free surface. The actual snow line may adjust seasonally, and be either significantly higher in elevation, or lower. The permanent snow line is the level above which snow wil ...

(in the Altai and the Sayan its depression gave about 1200 m in late

pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

) some of the lakes (

Chuya The Chuya (; , ''Çuy'') is a river in the Altai Republic in Russia, a right tributary of the Katun ( Ob's basin). The Chuya is long, and its drainage basin covers . The river freezes in October or early November and thaws in late April. The t ...

, Kuray, Uymon and others) began functioning in an under-ice regime because they never got free from ice for thousands of years. Such lakes turned into ice bodies of the “

aufeis Aufeis ( ) ( German for "ice on top") is a sheet-like mass of layered ice that forms from successive flows of ground or river water during freezing temperatures. This form of ice is also called overflow, icings, or the Russian term, naled (). Th ...

” type. They consisted of a thick lens of lake water, which was covered by lake

ice Ice is water that is frozen into a solid state, typically forming at or below temperatures of 0 ° C, 32 ° F, or 273.15 K. It occurs naturally on Earth, on other planets, in Oort cloud objects, and as interstellar ice. As a naturally oc ...

and

ice, and by

snow Snow consists of individual ice crystals that grow while suspended in the atmosphere—usually within clouds—and then fall, accumulating on the ground where they undergo further changes. It consists of frozen crystalline water througho ...

firn __NOTOC__ Firn (; from Swiss German "last year's", cognate with ''before'') is partially compacted névé, a type of snow that has been left over from past seasons and has been recrystallized into a substance denser than névé. It is ice that ...

sequence, too. “Aufeis” ledoyoms became independent centers of

with subradial ice outlets. Possible analogies of such an evolution mechanism and pre-glacial lakes are thick water lenses under a 3–4 kilometer-thick unit of the glacier cover at the sites of Dome B and

Dome Charlie Dome C , also known as dôme Circe, Dome Charlie ( US) or dôme Concordia, is located at Antarctica at an elevation of above sea level, on one of several domes of the Antarctic Ice Sheet. Location dome C is on the Antarctic Plateau, inland from ...

and the

Vostok Station Vostok Station (, , ) is a Russian research station in inland Princess Elizabeth Land, Antarctica. Founded by the Soviet Union in 1957, the station lies at the southern Pole of Cold, with the lowest reliably measured natural temperature on ...

in Eastern

Antarctica Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean (also known as the Antarctic Ocean), it contains the geographic South Pole. ...

. Thus, depending on the intermontane depression topography, the values, of the and of the glaciation energy, the interrelation of the glaciers and the ice-dammed lakes in the

mountains A mountain is an elevated portion of the Earth's crust, generally with steep sides that show significant exposed bedrock. Although definitions vary, a mountain may differ from a plateau in having a limited summit area, and is usually higher ...

south South is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both west and east. Etymology The word ''south'' comes from Old English ''sūþ'', from earlier Proto-Germanic ''*sunþa ...

of Western

could develop according to the following scenarios: #A ledoyom only (no ice-dammed lake). In such cases some glacial and water-glacial relief forms and sediments would remain in the basins #A water body and a ledoyom together (the stage of “catch lakes”). Certain forms of “dead ice” may remain in the basins, as well as intraglacial water-ice forms – eskers and kames which were projected onto the bottom lake deposits when the “shelf” ice descended #“Aufeis” ledoyoms #An ice-dammed lake only. Under different extensions of the

at different time periods, one and the same basin could have undergone different sequences of the lake-glacier events.''Рудой А. Н.'' Четвертичные ледоемы гор Южной Сибири // Материалы гляциологических исследований, 2001. — Вып. 90. — С. 40 — 49.

References

Keenan Lee. The AltaiFlood.

Ledoyom. Museum of Learning Explore a Virtual Museum of Knowledge

Alexei Rudoy. Ледоёмы (ice body): обзор

Alexei Rudoy. Giant current ripples: A Review (Гигантская рябь течения: обзор новейших данных). 29. 12. 2010.

Alexei Rudoy. Прошлогодний снег. – Climate, ice, water, landscapes
{{Webarchive, url=https://web.archive.org/web/20110506040501/http://ice.tsu.ru/index.php?option=com_content&view=category&layout=blog&id=8&Itemid=99 , date=2011-05-06 Geomorphology Glaciology