# Thread: as it runs down, recedes

1. ## as it runs down, recedes

Hi,

I was wondering if someone could take a look for me at these two questions.

The professor is discussing rock formations.

... ...
On a mesa, condition are optimal for erosion. With enough time, even the durable top of a mesa will decrease in size. The sides of a mesa are often made of shale or softer sandstone. The slope of the sides will increase the water's speed and force as it runs down.( Does it means "as the slope of the sides runs down", or "as the water runs down" ? ) Freezing and thaw loosen the surface rock. Debris carried by the running water cuts away the softer surface rock.As the softer base of the mesa recedes, (What does "recedes" mean here? I can not get it! ) the edge of the top is weakened, and it eventually cracks, splits, and falls.
... ...

2. ## Re: as it runs down, recedes

Originally Posted by IMPSX-UE
Hi,

I was wondering if someone could take a look for me at these two questions.

The professor is discussing rock formations.

... ...
On a mesa, condition are optimal for erosion. With enough time, even the durable top of a mesa will decrease in size. The sides of a mesa are often made of shale or softer sandstone. The slope of the sides will increase the water's speed and force as it runs down.( Does it means "as the slope of the sides runs down", or "as the water runs down" ? ) Freezing and thaw loosen the surface rock. Debris carried by the running water cuts away the softer surface rock.As the softer base of the mesa recedes, (What does "recedes" mean here? I can not get it! ) the edge of the top is weakened, and it eventually cracks, splits, and falls.
... ...
Hello IMPSX-UE,

Your first question: The water runs down the slope

Your second question: The rock recedes means that base of the mesa erodes and moves back. Imagine you put a stick in the ground against the base of the mesa. Now wait 1,000 years and go back. The stick would still be in the same place, but the base will have moved back and won't be touching the stick anymore -the base will have "receded".

I hope that helps.

Matthew Balson
Competence home

3. ## Re: as it runs down, recedes

Originally Posted by competence
Hello IMPSX-UE,

Your first question: The water runs down the slope

Your second question: The rock recedes means that base of the mesa erodes and moves back. Imagine you put a stick in the ground against the base of the mesa. Now wait 1,000 years and go back. The stick would still be in the same place, but the base will have moved back and won't be touching the stick anymore -the base will have "receded".

I hope that helps.

Matthew Balson
Competence home
Thank you, competence. I get it now!

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