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Iceage melt
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Scientists gathering evidence of ancient ice sheets uncovered a new mystery about what's happening on the Arctic sea floor today.
Sonar images revealed that, in some places, ocean currents have driven the mud along the Arctic Ocean bottom into piles, with some mud waves nearly 100 feet across.
Around the world, strong currents often create a wavy surface on the ocean bottom. But scientists previously thought the Arctic Ocean was too calm to do so.
Leonid Polyak, a research scientist at Byrd Polar Research Centre at Ohio State University, said that it's too early to know how the waves formed.

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 Springtails, mites, worms and plant life could help solve the mystery of Antarcticas glacial history according to new research published in the journal Science this week.
Scientists from British Antarctic Survey (BAS) and Massey University New Zealand report that of the evolutionary history of Antarcticas terrestrial plant and animal life does not reconcile with current reconstructions of past glacial ice extent going back more than 23 million years.
In todays warm period less than 1 percent of Antarctica is ice-free. It has been assumed that during ice ages there was insufficient ice-free land for Antarctic plant and animal species to survive and evolve. However scientists report that an exceptional long-term evolutionary persistence, isolation, and a striking capability to survive global climate change, appear to be the norm rather than the exception for the terrestrial world.

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According to this new study, carbon dioxide alone did not cause the end of the ice age. The article explores a few mechanisms that might have cause the temperature change. One of the main findings is that deep ocean temperatures warmed much earlier than sea surface temperatures. This is thought to be significant in the warming process which ended the ice age.



Deep-sea temperatures rose 1,300 years before the rise in atmospheric CO2, ruling out the greenhouse gas as driver of meltdown, Lowell Stott said in his study published online Sept 27 in Science Express.

"There has been this continual reference to the correspondence between CO2 and climate change as reflected in ice core records as justification for the role of CO2 in climate change. You can no longer argue that CO2 alone caused the end of the ice ages" - Lowell Stott.

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While an increase in atmospheric CO2 and the end of the ice ages occurred at roughly the same time, scientists have debated whether CO2 caused the warming or was released later by an already warming sea.
The best estimate from other studies of when CO2 began to rise is no earlier than 18,000 years ago. Yet this study shows that the deep sea, which reflects a good picture of oceanic temperature trends, started warming about 19,000 years ago.

What this means is that a lot of energy went into the ocean long before the rise in atmospheric CO2 - Lowell Stott.

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Disasters resembling the biblical Deluge often happened in Eurasia when glaciers occupied more space than they do now. In the north, the glacier served as a natural dam for Siberian rivers, and gigantic lakes were formed in northern Asia. In the mountains, glaciers formed dammed basins, which periodically burst and flooded vast territories. Huge water and mud flows rushed out at the speed of 20 meters per second.
Researchers of the Irkutsk State University and Institutes of the Earths Crust and Geochemistry (Siberian Branch, Russian Academy of Sciences) have recently discovered traces of a catastrophic hydrobreaking in the middle flow of the Onon river, in Tchasuchey deep (Transbaikalia). They made the discovery having investigated the relief of this area with the help of GoogleEarth, so anyone can look at evidence of the biblical-scale flood by typing barun torey (Barun Torey lake in the Chita Region) in the search line and by scrutinising the locality stretching towards the north-west of the water body approximately through to Tchasuchey.

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The point is in the relief of Tchasuchey deep - hills, mounds and ridges, shallow gullies and lakes in the shallow gullies are oriented from the north-west to south-east in that region. Linearly oriented ridge and shallow gullies system is the sign that once a water flow used to rush here. At the northern boundary of the deep, the lakes are big, but within its boundaries they are shallow. The majority of the lakes are oval and round, but few having an elongated shape are pulled out strictly in the direction from the north-west towards the south-east.
Geologists have been debating so far about the origin of ridges and mounds oriented in one direction if they are of aeolian origin (or wind origin, when the wind sweeps dunes together), or of fluvial origin when the same is done by running water. The Irkutsk researchers believe that a catastrophic debacle of a gigantic pond took place there, probably this is connected with Selengin Lake that existed in former times and occupied a major part of mainland towards the east of Baikal. The fact that the shallow gully zones alternate with the mound zones is to the credit of the above hypothesis. Hills and ridges prevail in the middle part of Tchasuchey deep, but in the north and in the south, near Barun Torey Lake, shallow gullies and deeps are predominant.

Such geological structures continue up to Harbin and Changchun in China, slightly turning to the north. Judging by the relief in the region of China, it is apparent that the flow broke down into several smaller ones.
It is interesting to note that positive forms of the relief are similar to baire hillocks in the Caspian Sea region. The same parallel chains of hills consisting of sand and clay stretch in latitudinal direction along Manych shallow gully, on the spot of hypothetical strait between the Caspian and the Black Sea. They were first described by C. Baire and are called after him. Similar formations also exist in Western Siberia where water inrush went from the east to the west. So, it means that the Deluges were not infrequent during the glaciation era.

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During the last Ice Age, the ice dammed enormous lakes in Russia.

I siste istid demte isen opp enorme innsjøer i Russland. Flere ganger var dreneringssystemet snudd og elvene rant sørover. Nå studerer en gruppe forskere hva som skjedde da isen smeltet og innsjøene tappet voldsomme mengder ferskvann ut i polhavet.
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During the last Ice Age, the ice dammed enormous lakes in Russia. The drainage system was reversed several times and the rivers flowed southwards. A group of geologists is now investigating what took place when the ice melted and the lakes released huge volumes of fresh water into the Arctic Ocean.

The ice-dammed lakes in Russia were larger than the largest lakes we know today. The entire drainage system in Russia has been reversed several times during the past 130 000 years. The heavy ice cap covering the land area in the north dammed up lakes and forced the large rivers, the Dvina, Mezen, Pechora and Vychegda, to flow southwards to the Caspian Sea, the Black Sea and on to the Mediterranean - Eiliv Larsen, a geologist at the Geological Survey of Norway (NGU), tells me.

He is in charge of the important SciencePub International Polar Year project that is studying natural climate changes in the Arctic and the ways in which man has adapted to them.

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When do ice ages begin? In June, of course.
Analysis of Antarctic ice cores led by Kenji Kawamura, a visiting scientist at Scripps Institution of Oceanography, UC San Diego, shows that the last four great ice age cycles began when Earths distance from the sun during its annual orbit became great enough to prevent summertime melts of glacial ice. The absence of those melts allowed buildups of the ice over periods of time that would become characterized as glacial periods.
Results of the study appear in the Aug. 23 edition of the journal Nature.

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Antarctic Glacial Maximum
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 Continental glaciers originating at both poles reached their farthest extent about 20,000 years ago, marking a time known as the Last Glacial Maximum.
Comparisons of ice cores from Greenland and Antarctica show that as these glaciers melted, warming occurred in asynchronous stages at the poles. While many northern hemisphere climate records match ice core records from Greenland, few southern hemisphere records exist to compare with ice core data from Antarctica.
Calvo et al. analyse a marine core collected off South Australia and find that it contains detailed signatures of surface temperatures of waters that washed over it since the glacial maximum.
Data from this core match well with Antarctic ice cores and paleoclimate records from the Australian continent, showing no signature of the Younger Dryas, a cooling event known to have occurred in the Northern Hemisphere about 13,000 years ago.
The new core data also reveal a progressive drop in sea surface temperatures over the last 6,500 years, an observation not seen before for the Australian region.

Title: Antarctic deglacial pattern in a 30 kyr record of sea surface temperature offshore South Australia
Authors: Eva Calvo: Institut de Ciències den Mar, Consejo Superior de Investigaciones Científicas, Barcelona, Spain;
Carles Pelejero: Institució Catalana de Recerca i Estudis Avançats and Institut de Ciències den Mar, Consejo Superior de Investigaciones Científicas, Barcelona, Spain;
Patrick De Deckker: Department of Earth and Marine Sciences, The Australian National University, Canberra, Australia;
Graham A. Logan: Petroleum and Marine Division, Geoscience Australia, Canberra, Australia.
Source: Geophysical Research Letters (GRL) paper 10.1029/2007GL029937, 2007

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Ice Age survivors
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Crymostygius thingvallensis, the only species in a recently described family of groundwater amphipods Crymostygidae. Many scientists believe that the ice ages exterminated all life on land and in freshwater in large parts of the Northern Hemisphere, especially on ocean islands such as Iceland. Scientists at Holar University College and the University of Iceland have challenged that belief, at least when looking at groundwater animals. They have discovered two species of groundwater amphipods in Iceland that are the only animals species found solely in Iceland.

These finding can only be explained by these animals surviving glaciations in some kind of refugium under the glaciers - Bjarni K. Kristjánsson, the scientist who found the species.

The time since the end of the last glaciation is not enough for a family to evolve.  If our theory is right, we have discovered the oldest inhabitants of Iceland, and that can help us further understand how Iceland was formed -  Svavarsson.

Kristjansson and Svavarsson find it likely that the amphipod came to Iceland as early as 30-40 million years ago, when the volcanic island was being formed.

Source : University of Chicago Press Journals


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RE: Iceage melt
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Discoveries of a butterfly species' DNA in the Far East and Western Europe may rewrite the known history of the Pleistocene Ice Age.
 Italian researchers Valerio Sbordoni and Paolo Gratton of the Rome Tor Vergata University said traces of the species' DNA have been found beyond the range once associated with the insect's history.
The Italian duo, along with Polish Academy of Sciences researcher Maciek Konopinski, used the new data to create an updated map of the world's greenery during the global ice age more than 10,000 years ago.

"The evidence from the mitochondrial DNA strongly suggests that large patches of the world's forests survived the impact of the last Ice Age and were alive and well as far back as 150,000 years ago. There were definitely oases in which the Parnassius mnemosyne butterfly thrived, especially in the Carpathians and the ancient German region of Pannonia" - Valerio Sbordoni.

UPI

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