The theory of continental drift by Alfred Wegener states that all land masses were originally united
in a single supercontinent known as Pangaea (250 million years ago). He shows
evidences like continental fit, similarity of rock sequences, glacial till and
striations, fossils (cynogathus-land reptile, lystrosaurus-land reptile,
mesosaraus-freshwater reptile, glossopteris-fern plant) to support his theory but
what was lacking is that it lacked a mechanism to explain HOW the continents
moved apart. But Harry Hess, a geologist and Navy submarine commander during
WWII <span>brought up a new
evidence to add in support of Wegener’s theory: the idea of seafloor spreading and magnetic reversals.</span>
<u>Answer</u>: e) Volcanic activity in the region leaves behind valuable minerals.
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<u>Explanation</u>: Volcanic activity has played an important role in the creation of the Cascade Mountains as they were originally created through the subduction of two continental plates.
It is well known that gold deposists are often found through volcanic systems. Water heated by volcanoes will become very acid and thus dissolve surrounding rocks. This water that will contain gold and other metals will then follow fractures through the bedrock towards the surface. In time, these will turn into gold veins or lodes.
