There is geologic evidence that the earth has experienced many episodes of mountain building and erosion. true or false

True

Explanation:

There are several geologic evidences that points to the fact that the earth has undergone different episodes of erosion and mountain building.

These evidences are the key to James Hutton's proposition of the "law of Uniformitarianism". The law which states that " the present is the key to the past and geologic processes that are occurring today have occured in the times past".

Evidences of erosion can be found mostly in sedimentary rock layers. Some of them occur as time gaps/lapses within rock units and they are called unconformity surfaces. Sometimes we can see them as erosional features in sedimentary beds.

Evidences of mountain building can be found in different Orogenic cycles terranes have been placed into. The earth is a dynamic planet and the internal heat engine combines with surface forces to move rocks through different types. Some areas believed to have been raised continental platforms are now stable cratons and shields. Dating rocks from such terrane would reveal several episodes of deformation which corresponds to mountain building cycles..

low freq = 100 mhz

low wavelength =101.7m

length = 3x10^8/freq

54 degrees incident angle = reflected angle

angle is from normal turned to line of ray