The Earth Recycles Itself

"Save the whales," "Save the Earth," "Hug a tree," are all slogans of the environmentalist groups which grab our attention. Surprisingly, these slogans would better serve all of us if reworded to say, "Save ourselves ... the planet will be fine." Due to the ongoing process of plate tectonics, the Earth's surface is being repeatedly recycled all by itself. Due to the ongoing process of the rock cycle, the rocks of the planet are repeatedly recycled, and without our help. The most important resource of all is water, and it too is recycled by planetary processes. In fact, the very chemicals upon which we depend for life are all recycled by natural mechanisms. The Earth simply dees not need the humans to save it. However, as you will learn from the study of this topic, humans have had a dramatic and often thoughtless impact on the latter two cycling systems, and therefore it is time that you learn what you can do to make this planet a better place for your future and your children's future.

THE TECTONIC CYCLE

THE ROCK CYCLE

THE WATER CYCLE

BIOGEOCHEMICAL CYCLES


Volcanoes and collision centers build huge mountains, and wind and rain erode them to sea level Ocean bottoms are newly created at spreading centers, but re-melted at subduction zones. The Earth's rock is melted, solidified, layers, reformed, and then re-melted only to start all over again in the endless Rock Cycle. Hot rock wells up from the deep interior, releases its heat and lava at the surface, cools and sinks back into the interior in a half-billion year cycle. Any rock which comes from melt is called Igneous. Granite and Basalt are forms of igneous rock, along with quartz, mica, feldspars, hornblende, biotite, etc. All of these rock names are composed of different minerals. It is the type and size of minerals in any rock which gives it a special nature, and allows geologists the means to identify rocks by content. As wind and rain erode this rock, it breaks down into tiny pieces and these are layered on top of each other, chemically bonded and pressurized together to make Sedimentary Rock. Sedimentary rock made up of pulverized granite is sandstone. Other forms are limestone, shale, and slate. Sometimes, either sedimentary or igneous rock comes in contact with heat or pressure ... not enough to melt it, but enough to reorganize the minerals. Such heated and squeezed granites become schist and gneiss, and are called Metamorphic for their organization has changed. Heated sandstone becomes quartzite. Heated limestone becomes marble. Metamorphic rock can be eroded and layered into sedimentary form or melted and become igneous again. Sedimentary rock can be metamorphosed or layered again, or melted to become igneous. Throughout the Earth's lifetime, all the surface rock is subjected to weathering, melting, and metamorphism, and it is all recycled.

What should we do when the environment groups come knocking on our door begging to send money to save the planet? Why, Nothing. Save your money. Put it in a mutual fund, where it may mature in spite of the present volatile stock market. And in the meantime, as you wait for your few dollars to multiply into millions, go ahead and pollute your neighborhoods and roadsides with trash. Build huge landfills and tap the methane gas for future national fuel needs. Use our nation's military might to strike fear in our enemies and bring them to their knees in submission to our capitalistic way of life. If they refuse to provide ridiculously cheap labor to make basketball shoes, them nuke them. The earth does not care one bit because it will recycle all of the material and make it into new igneous rock. We might all be long gone, the birds might stop singing, and the trees disappear, but the planet will survive just fine. Oh, the cockroach will almost certainly inherit the Earth.

However, if you are concerned about leaving a better world for your children, then reduce, reuse, and recycle and save the Earth some hard labor. This would be gneiss of you.

You are ready to study the Earth's atmosphere, weather, and recycling of biogeochemicals, you are asked to go first to the Rock Cycle, or you can move return to the Earth Introduction.


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