The surface of the earth is approximately equal to 510, 100, 000 km2, which at present time over seventy percent of the total exterior is mainly water. Most of the bulk of the earth’s water is in the form of water; however there is still a substantial portion that is in a crystallized form known as ice. Ice in itself is just a solid phase of water caused by sub-below temperatures, but even ice comes in many shapes and sizes.
What is a glacier?
The word glacier comes from the French by way of theVulgar Latin version Glacia, and eventually the Latin word Glacies, which simply means ice! A glacier is in essence a massive, slow-moving collection of formed ice that builds through a complex process of compaction and recrystallization of snow ice and air. Basically, if you take a huge chunk of ice, melt it slightly, add some snow and a few other elements, continuously repeat the process over a couple decades and voila: you have the beginnings of a glacier. Most glaciers can contain various elements ranging from basic ice, water, air and snow, but overtime rock and dirt debris can also collect within the layers of a glacier.
Most glaciers are found inland, but due to slippage and other natural occurring movement a glacier can be found both on land, or in a body of water. Large glaciers that border on a body of water are commonly described as an ice shelf, while the bulk of the glacier surface can span both inland or be submerged in water. Large chunks that break off form a new formation called an Iceberg, which can remain floating for substantial periods of time before breaking up or melting.
What is Glaciation:
A Glaciation can be defined simply as the birth and growth of a glacier, although the complexity of the formation, movements and recession is not as simplistic as it may seem. Recent geographic evidence shows that at present the total glacial surface equals to approximately 10% of the earth’s land area, a majority of these massive ice formations can be found under the Antarctica and Greenland ice shelves.
Most of the studies conducted on Glaciations today are focused on expansion and recession of current known glaciers, which can be impacted by environmental weather changes, erosion, and even massive land shifting.
How are glaciations recorded and tracked?
Glaciations have been categorized into four major periods throughout Earth’s history. Each period is measured in units of time called Ma, which is the symbol for a mega annum or one million years.
030- Present = Neogene Period
360-260 = Carboniferous and Permian Period: Named Karoo
450-420 = Ordovician and Silurian Period: Named Andean-Saharan
800-635 = Cryogenian Period: Named Cryogeneian
2100-2400 = Siderian and Rhyacian: Named Huronian Glaciation
Over the last half million years there has been a concentrated amount of data compiled in correlation to marine records retrieved, topological mapping, along with other information from ice cores and various other scientific study methods. During these periods specific glacial/interglacial cycles have been recorded that are divided up into five Pleistocene cycles.
There is also a land-based chronology of glacial cycles that occurred during the Pleistocene Epoch, which are as follows.
1. Wurm during glacial period 12,000 110,000 years.
– Riss Wurm during interglacial period 110,000 130,000
2. Riss during glacial period 130,000 200, 000 years.
– Mindel-Riss during interglacial period 200,000 300,000 years.
3-5th. Mindel during glacial period 300,000 455,000 years.
– Gunz-Mindel during interglacial period 455,000 620,000 years.
7. Gunz during glacial period 620,000 680,000 years.
I will be the first one to admit to the sheer complexity of the whole subject, but despite what all these tables and numbers mean, they are still very important to understand the past, present and our future. Another thing about glaciers and glaciations is the magnificent beauty of these monolithic formations.
Glaciers store approximately 75% of the worlds total freshwater on earth, and if they were all to melt at once the water levels would rise over 70 meters (aprox 250 feet). The real science behind the study of glaciations is vital so we can begin to understand how mankind is changing the global environment. Glaciers new and old, small and large are all very important components of our world, and the study of glaciations is like a window to the past and hopefully to our future!
