Rock Cycle
To introduce Rock Cycle, I asked the following questions based on the following slides.
Every rock can be formed into another rock type simply by going through the process to make that rock.
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The whole point of today is to realize that you can take any rock and subject it to different environmental conditions that will alter that rock and transform it into another type of rock. For instance, I can take the minerals found in Granite and break the quartz minerals apart into small sand size pieces and react the plagioclase mineral with water to form the clay minerals. By breaking it apart into sediment, I'm weathering it. When I carry it away, I'm eroding it away from the source. When I deposit it somewhere else, I form layers of sediment (deposition). When I get enough layers on top, the layers deeper down below begin to compress & lithify from the dissolved minerals in the water precipitating out of solution. This acts like the glue that binds all the sediments together. When this happens - I formed a sedimentary rock.
If I take sandstone, I can get it warm enough and with enough pressure, I can get it to partially form quartz crystals - and turn it into quartzite.
If I take shale and apply heat and pressure, I can turn it into slate.
Take these rocks and add more heat, I can remelt it and form my igneous rock.
I can also take my igneous rock, like Granite, and skip the sedimentary process and form gneiss.
The point is that rocks have been around for a long time. They are never really created, nor are they destroyed - rather recycled. So really, it should be called the Rock Re-cycle instead of the Rock Cycle.
Here is a youtube video on the Rock Cycle
If I take sandstone, I can get it warm enough and with enough pressure, I can get it to partially form quartz crystals - and turn it into quartzite.
If I take shale and apply heat and pressure, I can turn it into slate.
Take these rocks and add more heat, I can remelt it and form my igneous rock.
I can also take my igneous rock, like Granite, and skip the sedimentary process and form gneiss.
The point is that rocks have been around for a long time. They are never really created, nor are they destroyed - rather recycled. So really, it should be called the Rock Re-cycle instead of the Rock Cycle.
Here is a youtube video on the Rock Cycle