Mechanical Weathering
Mechanical Weathering is the physical break down of rocks. There are three main processes I am going to touch on today: Ice Wedging, Sheeting and Spalling, and Disintegration.
First I’ll start with Ice Wedging. Ice wedging is when the constant freezing and thawing of ice applies enough force to break down rocks due to the fact that when a water molecule changes from a liquid to a solid it expands from a 105 degree angle to a 109 degree angle; this expansion can induce high stress to whatever it may be contained in. In order for freezing and thawing to occur temperatures in a region must be wet, there needs to be moisture present and enough of it to apply enough force to do some real damage. Next, that moisture needs joint or preexisting fracture or void to collect itself together, for water molecules do damage in numbers. and now probably the most important thing for ice wedging to occur is, that moisture needs to be able to periodically turn from a liquid to a solid back into a liquid, so on and so forth. Without ice there is no ice wedging, but just note the ice should not be long term, just enough to leave the rock F.U.B.A.R. This kind of weathering creates many many features such as talus cones, and boulder fields.
Next is sheeting and spalling. Sheeting happens when confining pressures are released and the rock pretty much does the equivalent of popping it’s back.. if pieces of you flew off when you popped your back. He’s coming out of his cage (underground) and doing just fine. You can see this in emerging granitic rock. Spalling is what happens when extreme heat comes into contact with the rock. The outside of the rock is majorly affected making it expand in return meanwhile the inside is nice and cool amazingly unaffected.
Disintegration is one The Cure’s best albums... Okay just kidding (but not really), in geology disintegration is when plants, people and animals just mess with the rock and in turn it breaks down that way.
