The topic of global warming puts concern about the Earth’s polar ice caps. Has the Earth’s temperature warmed enough to cause the polar ice caps to melt, thus causing our oceans to rise? According to the EPA (Environmental Protection Agency), it took 100 years for the Earth’s sea level to rise to about 6 to 8 inches. But with the growing trend of global warming talks, people are becoming anxious about the polar ice caps melting. Are they really?

The largest polar ice cap on Earth is in Antarctica at the South Pole. It holds approximately 90 percent of the world’s ice content. If all of the ice in Antarctica melts, it will raise the sea levels all over world at about 61 meters or 200 feet. This is an unlikely occurrence, however, since the average Antarctic temperature is -37°C and never gets beyond freezing.

At the North Pole, the ice floats on the Arctic Ocean and are not likely to affect the sea level even if they melt.

Earths Polar Ice Cap

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The Earth’s mantle can be further divided into two layers; the upper and the lower mantle. The lower layer is generally in semi-liquid state and due to the heat generated by the core, convention currents occur in the mantle where rock rises due to high temperature but then sinks again slowly as it cools down. This event drives the movement of the tectonic plates.

On the other hand, the upper layer of the mantle doesn’t experience convection. It also comprises the lithosphere’s lower part. In addition, the layers of the mantle also differ in the amount of seismic velocities and density. The denser lower mantle is indicated by generally lower seismic velocities.

Like the planet’s crust, the mantle of the Earth’s moon is also rocky, rich in silicate materials and also accounts for a big percentage (about 50%) of its total mass.

Earth's Mantle

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Longitude specifies the east-west position of a particular point on Earth where an observer is located. Just like latitude, longitude is expressed in angular measurements, often in degrees, minutes and seconds and is denoted by the Greek letter lambda (λ). This geographic coordinate is often referenced to meridians or the great circles passing along the north and south poles. Cartographers and navigators use different references for measuring longitude.

The accepted worldwide reference as the zero meridian or the zero degrees longitude is the Prime Meridian or more popularly known as the Greenwich Meridian, which is the meridian that passes through the Royal Observatory in Greenwich, England. Longitudes indicated in published maps and international references systems are angular measurements located east or west of the Prime Meridian. Eastward measurements begin from zero degrees up to 180 degrees. Westward measurements take negative angular values from the Prime Meridian.

Like other geographic parameters, longitude is always used in conjunction with latitude to provide the best approximation of position on the surface of the Earth and to allow safe navigation.

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Igneous

For starters, rocks are classified according to how they are made. There are three types of rocks, namely, igneous, sedimentary, and metamorphic.

Under the Earth’s crust is the extremely hot mantle. It is interesting to note that the coolest outer part of the Earth’s mantle is around 1000°C Celsius or 1800°F. With that said, labeling the mantle as extremely hot is an understatement. The rock in this part of the Earth is molten, hot, white liquid.

Magma is made up of a combination of different elements, some of which are silica, iron, potassium, aluminum, and magnesium. Aside from these, other gasses are present such as oxygen, carbon dioxide, and sulfur dioxide. These elements in turn form chemical combinations that crystallize to form 8 basic rock forming minerals: olivine, quartz, amphibole, orthoclase, plagioclase, biotite, muscovite, and pyroxene.

Igneous rocks come from molten magma. When molten magma cools and crystallizes, an igneous rock is formed. This event only happens above the ground, like when volcanoes erupt. Magma immediately cools upon reaching the surface, usually in days or weeks. However, when magma forms in pockets underground, it cools more slowly that could take even million of years.

Rocks have always been in existence for a very, very long time. A study as to the circumstances and conditions by which these rocks were formed is one interesting read.

What are Igenous Rocks?

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