Geology Reference
In-Depth Information
65 million years and are still being built today by the movement of crustal plates on
earth's surface. I discuss the origin of some of these mountain ranges next.
Creating modern geography
So much evidence for Cenozoic geologic processes is available to geologists on the sur-
face of the earth that it could ill multiple topics. In this section, I describe only two of
the major mountain-building regions: the Alpine-Himalayan belt and the Circum-Pacific
belt. I also explain how some of the major features of the modern North American con-
tinent have evolved over the last 60 million years.
The Alpine-Himalayan belt
The Alpine-Himalayan orogenic belt extends from the Strait of Gibraltar in the western
Mediterranean, across the Middle East, through Turkey, and into Asia, where India and
China meet at the Himalayan mountain range. This belt is illustrated in Figure 21-1.
The European Alps and Himalayan mountains began forming during the middle of the
Mesozoic era (see Chapter 20), but things really picked up during the Cenozoic. As the
African continental plate moved northward, it crushed smaller plates into the European
continent, forming the Alps. This northward motion of the African Plate continues today,
compressing and deforming the rocks along the southern portion of Europe and slowly
closing off the Mediterranean Sea, which used to be a much larger ocean between Africa
and Europe.
Figure 21-1: The
Alpine-Himalayan
orogenic belt.
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