Giant current ripples
Encyclopedia
Giant current ripples are active channel topographic forms up to 20 m high, which develop within near-talweg areas of the main outflow valleys crated by glacial lake outburst flood
Glacial lake outburst flood
A glacial lake outburst flood is a type of outburst flood that occurs when the dam containing a glacial lake fails. The dam can consist of glacier ice or a terminal moraine...

s. Giant current ripple marks
Ripple marks
In geology, ripple marks are sedimentary structures and indicate agitation by water or wind.- Defining ripple cross-laminae and asymmetric ripples :...

 are morphologic and genetic macroanalogues of small current ripples formed in sand
Sand
Sand is a naturally occurring granular material composed of finely divided rock and mineral particles.The composition of sand is highly variable, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal...

y stream sediments.

The giant current ripple marks are important depositional forms in diluvial
Diluvium
Diluvium is a term in geology for superficial deposits formed by flood-like operations of water, and so contrasted with alluvium or alluvial deposits formed by slow and steady aqueous agencies...

 plain and mountain scablands.

Short history of the research

The history of the scabland studies has two distinct stages: the "old" one that began with the first works by J Harlen Bretz
J Harlen Bretz
J Harlen Bretz was an American geologist, best known for his research that led to the acceptance of the Missoula Floods, and also for his work on caves. He was born to Oliver Joseph Bretz and Rhoda Maria Howlett, farmers in Saranac, Michigan, as the oldest of five children...

 and Joseph Pardee
Joseph Pardee
Joseph T. Pardee was a U.S. geologist who worked for the U.S. Geological Survey, and contributed to the understanding of the origin of the Channeled scablands. He discovered the trail of evidence left by Glacial Lake Missoula, a lake created by an ice dam 23 miles wide and half a mile high during...

 in North America and lasted until the end of the 20th century that was crowned with the discovery of giant current ripple marks in Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...

, and a "new" one. The latter is associated with heated debates concerning the genesis of the relief under study and which involved a lot of Russian geologist
Geologist
A geologist is a scientist who studies the solid and liquid matter that constitutes the Earth as well as the processes and history that has shaped it. Geologists usually engage in studying geology. Geologists, studying more of an applied science than a theoretical one, must approach Geology using...

s, geomorphologists and geographer
Geographer
A geographer is a scholar whose area of study is geography, the study of Earth's natural environment and human society.Although geographers are historically known as people who make maps, map making is actually the field of study of cartography, a subset of geography...

s. The discussion about the origin of the giant ripples dealt at least to a certain extent with every aspect of the diluvial
Diluvium
Diluvium is a term in geology for superficial deposits formed by flood-like operations of water, and so contrasted with alluvium or alluvial deposits formed by slow and steady aqueous agencies...

 theory, from the genesis of the lakes themselves, their existence duration, possibilities of their cataclysmic failures, etc. to the origin of the diluvial forms - the aspects that have been accepted by many scientists worldwide, including an increasing number of Russian scientists.

The state of the problem in the 20th century. "Old hypotheses"

J Harlen Bretz
J Harlen Bretz
J Harlen Bretz was an American geologist, best known for his research that led to the acceptance of the Missoula Floods, and also for his work on caves. He was born to Oliver Joseph Bretz and Rhoda Maria Howlett, farmers in Saranac, Michigan, as the oldest of five children...

, the author of the hypothesis of the diluvial origin of the Channeled Scabland, considered mainly "giant gravel bars" (diluvial ramparts and terraces) among the diluvial-accumulative formations as a proof of his case along with the destructive forms of the scabland (gorges-coulee
Coulee
Coulee is applied rather loosely to different landforms, all of which refer to a kind of valley or drainage zone.The word coulee comes from the Canadian French coulée, from French word couler meaning "to flow"....

s, waterfall cataracts – chains of erosional dry falls
Dry Falls
Dry Falls is a 3.5 mile long scalloped precipice in central Washington, on the opposite side of the Upper Grand Coulee from the Columbia River, and at the head of the Lower Grand Coulee. Ten times the size of Niagara, Dry Falls is thought to be the greatest known waterfall that ever existed...

 washed of loose sediments by the floods of diluvial farewell rocks).

It was only after J. T. Pardee's report in Seattle at the Session of the American Association for the Advancement of Science
American Association for the Advancement of Science
The American Association for the Advancement of Science is an international non-profit organization with the stated goals of promoting cooperation among scientists, defending scientific freedom, encouraging scientific responsibility, and supporting scientific education and science outreach for the...

 in 1940 that the expression "giant current ripples" was introduced in the modern meaning. J. Pardee gave brief characteristics to the forms found by him already in the early 20th century while researching the Late Pleistocene lake Missoula. J. Pardee, who was the discoverer of this lake and named it, had kept silent for over thirty years until his retirement about cataclysmic outbursts of the giant North-American ice-dammed lakes
Proglacial lake
In geology, a proglacial lake is a lake formed either by the damming action of a moraine or ice dam during the retreat of a melting glacier, or by meltwater trapped against an ice sheet due to isostatic depression of the crust around the ice...

 in the Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

. As already mentioned, the "official" American geology represented by the United States Geological Survey
United States Geological Survey
The United States Geological Survey is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...

, which strictly controlled all scientific studies, strongly objected to J H. Bretz's hypothesis
Hypothesis
A hypothesis is a proposed explanation for a phenomenon. The term derives from the Greek, ὑποτιθέναι – hypotithenai meaning "to put under" or "to suppose". For a hypothesis to be put forward as a scientific hypothesis, the scientific method requires that one can test it...

 in the early 20th century. J. Pardee was a member of this organization. Even the title "Ripple marks (?) in the glacial lake Missoula" of Pardee's report proves the great significance attached by Pardee to the relief he discovered a few decades ago as an instrument for the reconstruction of Late Quaternary diluvial palaeohydrology in North America. Thus, it is this scientist's name that we should associate with the discovery and correct genetic interpretation of the relief of giant current ripples. After Pardee's publication in 1942 the giant current ripples have been found practically everywhere on the territory of the basaltic Columbia Plateau
Columbia Plateau
The Columbia Plateau is a geologic and geographic region that lies across parts of the U.S. states of Washington, Oregon, and Idaho. It is a wide flood basalt plateau between the Cascade Range and the Rocky Mountains, cut through by the Columbia River...

 (this was the direction of the cataclysmic outbursts of Missoula and other ice-dammed lakes).

A special study of the geomorphology and palaeohydrology of the American scabland was begun by Victor Baker. It was Baker who mapped all main fields of giant current ripples known today in America, and it was he who made first attempts to gain chief hydraulic characteristics of the Missoula floods
Missoula Floods
The Missoula Floods refer to the cataclysmic floods that swept periodically across eastern Washington and down the Columbia River Gorge at the end of the last ice age. The glacial flood events have been researched since the 1920s...

 according to the multiple measurements of paired parameters of diluvial dunes and their mechanical composition. Some other so far known means had certainly been used for the purpose as well since Bretz's times, in particular, the functional dependences by Schezi and Manning. However, those dependences estimated velocities and discharges of the floods at the channel line, and the data received, although imprecise, were tremendous. V. R. Baker calculated the palaeohydraulic data over the ripple fields, i.e. over the sites distanced from the channel line and (or) on wane of the floods, where the current velocities of the diluvial streams admittedly must have been less than maximum ones (all the same, they were hundreds of thousands of cubic kilometres per second).

For nearly sixty years the well known ice-dammed Lake Missoula (and other well-known North-American ice-dammed lakes) and its cataclysmic outbursts was considered as a unique one in the world's scientific literature. Special tourist routes were organised at most impressive sites of "giant vessels
Dry Falls
Dry Falls is a 3.5 mile long scalloped precipice in central Washington, on the opposite side of the Upper Grand Coulee from the Columbia River, and at the head of the Lower Grand Coulee. Ten times the size of Niagara, Dry Falls is thought to be the greatest known waterfall that ever existed...

", canyon
Canyon
A canyon or gorge is a deep ravine between cliffs often carved from the landscape by a river. Rivers have a natural tendency to reach a baseline elevation, which is the same elevation as the body of water it will eventually drain into. This forms a canyon. Most canyons were formed by a process of...

s-coulees, vast fields of giant current ripples and others. Here professional guides tell the tourists about hydrospheric catastrophes which took place in the ice ages in America.
The discovery of the relief of giant current ripples in the Altai
Altai Republic
Altai Republic is a federal subject of Russia . Its capital is the town of Gorno-Altaysk. The area of the republic is . Population: -Geography:...

 and Tuva
Tuva
The Tyva Republic , or Tuva , is a federal subject of Russia . It lies in the geographical center of Asia, in southern Siberia. The republic borders with the Altai Republic, the Republic of Khakassia, Krasnoyarsk Krai, Irkutsk Oblast, and the Republic of Buryatia in Russia and with Mongolia to the...

 and its correct diagnostics began a new stage in the paleogeographical research of the continents, a broad international cooperation and initiated new conclusions which have cleared up a lot of questions in the Quaternary geology and Paleohydrology of Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

 in Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...

.

Along with the development of the ideas about enormous dimensions and a big role of Pleistocene glacier-dammed lakes and their cataclysmic outbursts
Glacial lake outburst flood
A glacial lake outburst flood is a type of outburst flood that occurs when the dam containing a glacial lake fails. The dam can consist of glacier ice or a terminal moraine...

, a new branch of the scientific research which was called by the British geologist P. A. Carling "flood deposit sedimentology
Sedimentology
Sedimentology encompasses the study of modern sediments such as sand, mud , and clay, and the processes that result in their deposition. Sedimentologists apply their understanding of modern processes to interpret geologic history through observations of sedimentary rocks and sedimentary...

" is becoming more and more notable. In Russia in the middle 1990s the geological objects formed by the diluvial floods — floodstreams — were referred by the author to the research objects of Quaternary glaciohydrology based on the theory of the diluvial
Diluvium
Diluvium is a term in geology for superficial deposits formed by flood-like operations of water, and so contrasted with alluvium or alluvial deposits formed by slow and steady aqueous agencies...

 morpholithogenesis.

The history of the scabland studies is distinctly divide into two stages: the "old" one that began with the first works by J H. Bretz and J. Pardee in North America and lasted until the end of the last century that was crowned with the discovery of giant current ripple marks discovered in Eurasia
Eurasia
Eurasia is a continent or supercontinent comprising the traditional continents of Europe and Asia ; covering about 52,990,000 km2 or about 10.6% of the Earth's surface located primarily in the eastern and northern hemispheres...

, and a "new" one. The latter is associated with heated debates concerning the genesis of the relief under study and which have involved a lot of Russian geologists, geomorphologists and geographers. The discussion about the origin of the giant ripples deals somehow or other with all the aspects of the diluvial theory, from the genesis of the lakes themselves, duration of their existence, possibilities of their cataclysmic failures, etc. to the origin of the diluvial forms that have already become doubtless for many scientists in other countries and an increasing number of the Russian scientists as well.

In Russia nobody had known anything about the regime of ice-dammed lakes until the 1980s and, of course, had not looked for any traces of their failures, either. Although some lake terraces of the basinal preglacial bodies of water in the mountains of South Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

 were mapped in the early 20th century (it was done incidentally during some geological and botanical investigations), the question of the evacuation mechanisms of these lakes did not even arise. As a matter of fact, this question was (and by someones is still) considered rhetorical: since there are strandline
Strandline
The strandline, or high water mark, is the area at the top of a beach where debris is deposited. Where there are tides, this line is formed by the highest position of the tide, and moves up and down the beach on a fortnightly cycle...

s on the sides of the depressions, then the lakes used to dry gradually and slowly. Moreover, in some authors' opinions, the lakes appeared in the depressions, in particular in the Altai, only once, at the most – twice. And when such lake terraces could be poorly distinguished, if any at all, in the depressions, then the question of the lakes did not arise: there were not any lakes.

Nevertheless, in the late 1950s G. F. Lungershausen and O. A. Rakovets were the first to give a correct interpretation to a "mysterious" ridge-and-pading relief in Kuray intermountain depression. These scientists were the first to correctly define the genesis of the relief in the depression and to assume, according to the orientation of the diluvial dunes, the eastern direction of the runoff of the rivers, which is opposite to the contemporary one, at some moment in the history of the Altai. The genetic diagnostics of the giant ripples in the Kuray Basin had a general character and was essentially limited to the terminologically correct definition only (in fact, the purpose of the article of the authors mentioned was different). The article explained the origin of the direction of the water torrents proper by some neotectonic reasons.

New hypotheses of the origin of the giant current ripple marks

The notice made by G.F. Lungershausen and O.A. Rakovets about the diluvial origin of giant ripple marks in Kuray was denied by E.V. Deviatkin, who referred to an oral conclusion made by E.V. Shantser and wrote that the large ripple marks in Kuray Basin were results of heavy erosion
Erosion
Erosion is when materials are removed from the surface and changed into something else. It only works by hydraulic actions and transport of solids in the natural environment, and leads to the deposition of these materials elsewhere...

al processing of a huge fluvioglacial fan
Outwash fan
An outwash fan is a fan-shaped body of sediments deposited by braided streams from a melting glacier. Sediment locked within the ice of the glacier, gets transported by the streams of meltwater, and deposits on the outwash plain, at the terminus of the glacier...

. M.V. Petkevich expressed a similar opinion in her candidate thesis. She believed that the ridged relief on the right bank of the Tetio River in Kuray Basin was a washed proluvial fan.

Every single diagnostic sign of the giant ripples given in the corresponding section contradict this theory, especially the cross-layered texture of the sediments in the ripple marks which correlates with their morphology and the regular asymmetry of their slope
Slope
In mathematics, the slope or gradient of a line describes its steepness, incline, or grade. A higher slope value indicates a steeper incline....

s at all the locations. The petrography
Petrography
Petrography is a branch of petrology that focuses on detailed descriptions of rocks. Someone who studies petrography is called a petrographer. The mineral content and the textural relationships within the rock are described in detail. Petrographic descriptions start with the field notes at the...

 composition of the coarse-fragmental material in the ripple marks witnesses also against this hypothesis, it is alien to the bed rock of the basins of the Tetio and the Aktru rivers.

In addition, G.G. Rusanov found malachite
Malachite
Malachite is a copper carbonate mineral, with the formula Cu2CO32. This green-colored mineral crystallizes in the monoclinic crystal system, and most often forms botryoidal, fibrous, or stalagmitic masses. Individual crystals are rare but do occur as slender to acicular prisms...

, axinite
Axinite
Axinite is a brown to violet-brown, or reddish-brown bladed group of minerals composed of calcium aluminium boro-silicate, 3Al2BO3Si4O12OH...

, sillimanite
Sillimanite
Sillimanite is an alumino-silicate mineral with the chemical formula Al2SiO5. Sillimanite is named after the American chemist Benjamin Silliman . It was first described in 1824 for an occurrence in Chester, Middlesex County, Connecticut, USA....

 and cinnabar
Cinnabar
Cinnabar or cinnabarite , is the common ore of mercury.-Word origin:The name comes from κινναβαρι , a Greek word most likely applied by Theophrastus to several distinct substances...

 in the schlichs of the ripple marks in Kuray Basin, which are characteristic of the Kuray Ridge but not found in the schlichs of the end moraines of the Tetio River, the latter adjoining the fields of the giant ripples. Cinnabar is a heavy, fragile and quickly worn mineral. That is why, as G.G. Rusanov remarks, it cannot be carried away from its original source farther than over first hundreds of metres. Over longer distances this mineral can be transported only in suspension state. At the same time, galena
Galena
Galena is the natural mineral form of lead sulfide. It is the most important lead ore mineral.Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms...

, which is very characteristic of the moraines of the Tetio and the Aktru Valleys, is not found in the ripple sediments. Hence, pebble deposits adjoining the end moraines of the Tetio cannot be fluvioglacial or proluvial formations of the meltwater
Meltwater
Meltwater is the water released by the melting of snow or ice, including glacial ice and ice shelfs over oceans. Meltwater is often found in the ablation zone of glaciers, where the rate of snow cover is reducing...

 from the glaciers of the Aktru and the Tetio.

At that time P.A. Okishev flatly disagreed with his predecessors and contemporaries. He argued that the proofs of the erosional extension of a vast fluvioglacial fan here (in Kuray Basin) are unconvincing. In 1970 P.A. Okishev put forward the idea that the giant current ripple marks in Kuray depression are "inversional formations". "The ridges presently expressed in the relief used to accumulate as channel sediments within above-glacial floods of a vast flat glacial field and projected afterwards onto the substratum" .

A. N. Rudoy shall point out in this quotation that 1) P.A. Okishev simply described, though superficially, the mechanism of the esker
Esker
An esker is a long winding ridge of stratified sand and gravel, examples of which occur in glaciated and formerly glaciated regions of Europe and North America...

s, and 2) he emphasised the fluvial, channel origin of the ridges proceeding from their material composition and morphology.
This investigator developed his theory later in his book and his doctoral thesis (1984), but practically at the same time he put forward another hypothesis, a "glacial" one, without explaining anything or mentioning the "inversional relief". P.A. Okishev wrote that the giant current ripples in Kuray Basin are "bedded, small-ridged, poly-ridged" moraines. The "inversional relief" was forgotten by the author for ever and has never been mentioned again.
This author's unclear explanations of the essence of his second "moraine" hypothesis (he would have a third one as well) may be regarded in general as an attempt "to introduce something new" into the works by B.A. Borisov and E.A. Minina who, after many years of their geological surveys in the mountains of southern Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

, discovered and described the relief of "a washing board" (the phase of the rogen moraine according to the classification by Yu. A. Lavrushin. B.A. Borisov and E.A. Minina ascribed the relief of giant current ripples of all the districts where it had been found, described and more or less studied to that relief of the ribbed moraine, the latter really exists in many ancient glacial mountainous valleys of Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

, Middle Asia
Middle Asia
Middle Asia is a region of Asia from the Caspian Sea in the west, to Mongolia in the east, Afghanistan in the south, and Russia in the north. The geographical term has appeared sometime prior to the 20th century in the Russian Empire and was closely associated with the Russian Turkestan and the...

 and in other mountains.

The first investigator in Russia who not only correctly defined the genesis of the giant current ripples (we shall remind that this was done first by G.F. Lungershausen and O.A. Rakovets about twenty-five years before that time) but also described their composition and reconstructed (in a complex with other flood forms) palaeoglaciohydrology of the region of the geological surveys was V.V. Butvilovsky. However, his discovery was made far from the region where nowadays "lances are being broken". It was in the valley of the Bashkaus River in the Easter Altai]. As a matter of fact, V.V. Butvilovsky managed to describe the whole palaeohydrologic scenario of the last glacial age based on a small district, which corresponds well to the modern ideas about glacial palaeohydrology of the dryland. He also showed that the Quaternary ice-dammed lake of Tuzhar Village discovered by him outburst into the valley of the Chulyshman River
Chulyshman River
Chulyshman River is a river in Altai Republic in Russia. The length of the river is 241 km. The area of its basin is 16,800 km². The Chulyshman flows into Lake Teletskoye. It freezes up in late October - early December and stays icebound until late March - early May. Its main tributary is the...

 after having reached its critical level. He emphasised that in the valley of the Bashkaus River and the Chulyshman River there was only one but very powerful superflood with its maximum discharge of about 880 000 m3/s (the calculation was done according to the formula by Schezi). Later on, V.V. Butvilovsky developed his ideas and defended them in his doctoral thesis [Butvilovsky, 1993].
When working in the Central and South-Eastern Altay, A. N. Rudoy studied in this years the largest in the Altay ice-dammed lakes of Chuya, Kuray and Uymon Basins (Butvilivsky was in 1970s his student in Tomsk State University
Tomsk State University
Tomsk State University , formerly Imperial Tomsk University, is the first university in Siberia—it was founded in 1878 in Tomsk, Russia. TSU opened in 1888 with only one department, the medical school...

). In autumn 1983 Rudoy carried out some field research on the left bank site of the Katun River which is now known as "the field of giant current ripples of Platovo-Podgornoje". The result of the research was the first published work dedicated to the multiple cataclysmic outbursts of those tremendous Pleistocene ice-dammed lakes. That work was the first to give a detailed description of the structure of the relief of the giant current ripples at the foothills. Also the first attempt was made to define the palaeohydraulic characteristics of the diluvial floods according to the morphologic peculiarities of the ripples and their material composition.
In the early and middle 1980s special filed studies headed by the Alexei Rudoy were carried out at the discovered sites of the fields of the giant current ripples, four of which have become key ones in the course of time, i.e. they have been specially studied for many years by professionals from different countries and of different specialities. These key sites include: the location of giant current ripples of Platovo-Podgornoje; the location of diluvial dunes of the Little Yaloman – the Inia; the field of the giant current ripples in the central part of Kuray Basin and the diluvial dunes at the Basin (in Russian: urochishtshe) Kara-Kol on its western raised periphery.

Some reconstruction of the regime of the last glacial age, estimates of the glacial runoff at its maxima and post-maxima, on the one hand, and the discovery of the diluvial morpholithocomplex on the other hand, enabled us already at the late 1980s to outline a common palaeoglaciohydrologic situation of the Glacial Pleistocene for those territories of the Earth where the oroclimatic condition were similar to those of the mountains of Siberia. At the same time M.G. Grosswald described and physically interpreted for the first time fields of giant current ripples not in the Altai only but also in the intermountain depressions of Tuva and in the valleys of the Upper Yenisei. Nowadays these fields are also studied by international expeditions, some works paying a special attention to the giant ripple marks on the Sayany-Tuva table-land have been already published.

In early 1990s first international expeditions which specially studied the diluvial morpholithologic complex in Asia. Their purpose was to compare main palaeohydromorphologic characteristics of mountain scablands of Central Asia
Central Asia
Central Asia is a core region of the Asian continent from the Caspian Sea in the west, China in the east, Afghanistan in the south, and Russia in the north...

 which had been already developed in Russia by that time with those of the known plain diluvial associations of the Channeled Scabland territory in North America. The participants of those first expeditions were specialists from Russia (M.R. Kirianova, A.N. Rudoy), the United States (V.R. Baker), Great Britain (P.A. Carling), Germany (K. Fischer and M. Kuhle) and Switzerland (Ch. Siegenthaler).

In the second half of 1990s and at the beginning of the 21st century (until the field season of 2010) P.A. Carling carried out some more special expeditions in the Altai, their results were summed up in a cooperative work.

Later, a group of German sedimentologists under the direction of Ju. Herget worked successfully in the Altai. Several big articles presented the refined data of the palaeohydraulic parameters of the diluvial floods in the river valleys of the Chuya River
Chuya River
The Chuya River is a river in the Altai Republic in Russia, a right tributary of the Katun River . The Chuya is 320 km long, the area of its drainage basin is 11,200 km². The river freezes up in October - early November and breaks up in late April....

 and Katun River.

In 1998 S.V. Parnachov defended his candidate thesis based on the analysis of some well-known sections of the diluvial terraces at the Katun River and the Chuya River
Chuya River
The Chuya River is a river in the Altai Republic in Russia, a right tributary of the Katun River . The Chuya is 320 km long, the area of its drainage basin is 11,200 km². The river freezes up in October - early November and breaks up in late April....

, as well as on the data by P.A. Carling and conclusions of his own. The thesis paid a certain amount of attention to the key locations of the fields of giant current ripples discovered before. The investigator fulfilled, in particular, the petrographic and granulometric analyses of the clastic material of the giant ripples at the key sites. S.V. Parnachov based himself on the calculations of the jökulhlaup
Jökulhlaup
A jökulhlaup is a glacial outburst flood. It is an Icelandic term that has been adopted by the English language. It originally referred to the well-known subglacial outburst floods from Vatnajökull, Iceland which are triggered by geothermal heating and occasionally by a volcanic subglacial...

 discharges by P.A. Carling – 750,000 m3 per second – and came to the conclusion that there were no fluvial catastrophes but there were several lake outbursts with the discharges not higher than those of contemporary big rivers. Instead of the diluvial sediments this author suggested a new geological formation – the "flood alluvium".

Consequently, S.V. Parnachov distinguished the "flooding period" in the Altay of about 150 000 years long. The genesis of the basinal lakes, however, S.V. Parnachov admitted so far as ice-dammed one.
Two years later I.S. Novikov joined the investigations by S.V. Parnachov. These geologists drew a conclusion that "the glaciers could not" dam themselves such big lake depressions, consequently the dams were "ice-tectonic" ones. So, according to the authors quoted, during the "flooding period" that lasted for about 150 000 years there were no less than seven cataclysmic flooding occurrences associated with the outbursts of the palaeolakes. Moreover, a tectonic obstacle also played a role in the damming of the lakes during the very last degradation phases of the Würm glacier.

Alternate explanations

"New antidiluvialists" have put forth alternate explanations to the giant current ripples theory.
  • The giant current ripples in the valleys of the Altai (except Kuray depression) are ordinary ripples like contemporary river dunes of large rivers (i.e. – "nothing special"). The author of the quotation is A.V. Pozdniakov who observed some forms of such ripples in the valleys in the Far East
    Far East
    The Far East is an English term mostly describing East Asia and Southeast Asia, with South Asia sometimes also included for economic and cultural reasons.The term came into use in European geopolitical discourse in the 19th century,...

    . He was joined by D.A. Timofeev and some participant of a school-seminar of the geography Committee of the Russian Academy of Sciences, including G. Ya. Baryshnikov who, 10 years earlier, proved the cataclysmic origin of the giant current ripple marks at the foothills of the Altai and at the middle reaches of the Katun.
  • The giant current ripples in Kuray depression are ripples but they developed "under the conditions which were similar to or slightly different from the contemporary ones, and not on the bottoms of the deep pre-glacial lakes which outburst catastrophically". Quoted from an essay in "The Geomorphology" written by G. Ya. Baryshnikov and others with references to the opinion of the participants of the above-mentioned school-seminar adopted after the discussion.
  • The giant current ripples in Kuray depression are not ripples at all but the consequence of a meteorite fall.
  • The giant current ripples in Kuray depression are not ripples at all but the consequence of an earthquake. These hypotheses contain both elastic vibrations and cryptoexplosion structures… The authors are A.V. Pozdniakov and A.V. Khon.
  • The giant current ripples in Kuray depression are cryogenic erosional formations. The authors are A.V. Pozdniakov and A.V. Khon again, also P.A. Okishev.

Megaflooding on Earth and Mars

While the Russian science is discussing the genesis of the giant current ripples at the just briefly described scientific level, American and British geologists and planetologists have discovered such relieves on Mars according to the data on the giant current ripples in the Altai and even calculated the hydraulic parameters of those diluvial floods.

Main diagnostic features of the giant current ripple marks

Up to the present, hundreds of locations of the fields of giant current ripples have been discovered in North America and Northern Asia. Here is a brief description of main characteristics of this relief and its sediments at the key, today most often visited, sites in the Altai and Tuva
Tuva
The Tyva Republic , or Tuva , is a federal subject of Russia . It lies in the geographical center of Asia, in southern Siberia. The republic borders with the Altai Republic, the Republic of Khakassia, Krasnoyarsk Krai, Irkutsk Oblast, and the Republic of Buryatia in Russia and with Mongolia to the...

 with the necessary references to the chief publications for the other territories.
  1. Wave height from 2–20 m with the wave length from 5–10 m to 300 m
  2. Ripple marks are stretched transversely to the diluvial floods. They are clearly and regularly asymmetric. The proximal slopes are orientated towards the flood, they are more gentle with slightly prominent profiles (The profile of "the whale back"); the distal slopes are steeper with slightly concave profiles nearer to the crest
  3. Big poorly-rounded boulders and blocks are often to be found at pre-crest and upper part of the slopes
  4. Giant current ripple marks are constituted by deposits of pebbles and small boulders with a low percentage of coarse- and big-grained sand. The fragmentary material is diagonally cross-bedded agreed with the dip of the distal slope. Irrespective of the age of the ridges (normally, it is the time of the last late- and post-glacial age) the sediments are loose and dry, fragments are not hardened with loamy and silt.
  5. Fields of giant current ripples are situated close to the run-off ways from basinal ice-dammed lakes and to vortex zones within valley expansions


Unfortunately, no diagnostic features of the lithology of giant current ripples have been cleared up, yet, that could differentiate the latter from other genetic types of loosed sediments in sections. The presence of cross-bedded series in some layers with evidently fluvial genesis which were diagnosed by V.V. Butvilovsky as buried ripples (e.g. an exposure in a pit near the mouth of the Isha River, etc.) does not look as remarkable in the nature as it is described by the author. A. N. Rudoy useds to work for a long time at this and similar exposures (e.g. by the settlement of Karlushka). Nothing, except the fact of the cross dipping of fluvial boulder pebbles, can tell the investigator that he sees some buried giant current ripples. One can nothing but assume this. And an abrupt dipping of bedded alluvial channel fractions is a very often seen phenomenon. The problem of diagnosing diluvial sediments in a buried state, i.e. without any geomorphological control, may apparently be solved not only, if at all, by studying peculiarities of the diluvial texture, but by means of the microscopic lithological studies of the sediments of giant current ripples, i.e. mineralogy of fine fractions, grain shapes, analysis of accessories, etc. Then these correctly summarised data must be compared with various phases of the contemporary mountainous alluvium at the analogous sections.

See also

  • J Harlen Bretz
    J Harlen Bretz
    J Harlen Bretz was an American geologist, best known for his research that led to the acceptance of the Missoula Floods, and also for his work on caves. He was born to Oliver Joseph Bretz and Rhoda Maria Howlett, farmers in Saranac, Michigan, as the oldest of five children...

  • Missoula Floods
    Missoula Floods
    The Missoula Floods refer to the cataclysmic floods that swept periodically across eastern Washington and down the Columbia River Gorge at the end of the last ice age. The glacial flood events have been researched since the 1920s...

  • Glacial lake outburst flood
    Glacial lake outburst flood
    A glacial lake outburst flood is a type of outburst flood that occurs when the dam containing a glacial lake fails. The dam can consist of glacier ice or a terminal moraine...

  • Diluvium
    Diluvium
    Diluvium is a term in geology for superficial deposits formed by flood-like operations of water, and so contrasted with alluvium or alluvial deposits formed by slow and steady aqueous agencies...


External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK