Question

The Cascade Mountains in Washington were formed, in part, from the subduction of the Juan De Fuca Plate. Modern-day topography in the Cascade Mountains is a result of

a) continued volcanic action
b) continental and alpine glaciers.
c) more recent subduction of the Juan De Fuca Plate.
d) continental glaciers that retreated 12,000 years ago.

Answer 1

The correct answer is A. The Cascade Mountains in Washington were formed, in part, from the subduction of the Juan De Fuca Plate. Modern-day topography in the Cascade Mountains is a result of continued volcanic action.

Step-by-step explanation:

The Cascade Mountains is a mountain range extending across the west coast of North America, between the states of California, Oregon and Washington in the United States and the province of British Columbia in Canada.

The mountainous system is characterized by volcanoes which constitute its highest peaks. Among all, Mount Rainier is the highest peak in the chain reaching a height of 4392 meters. All the volcanic eruptions that took place in historical times in the continental United States (excluding the islands of Hawaii and Alaska) took place in the Cascade Mountains. The two volcanoes that have had eruptions more recently are Lassen Peak, whose last explosive episode dates back to 1917, and the famous Mount Saint Helen, with its catastrophic eruption of 18 May 1980.

Answer 2

a) continued volcanic action

Step-by-step explanation:

When a plate subducts beneath another, it is typical to see volcanic activities in the region of the subduction zone.

Subduction zones occur in convergent margins. They arise as a result of downslipping of the denser plate. When this occurs, the denser plate keeps subducting and the less dense one continues to override it.

The Juan De Fuca Plate subducts beneath a continental plate.

The result of subduction is usually a series of volcanic activities which results from the melting of the descending plate. The subducting plate begins to melt as the geothermal gradient increases. The melt can find its way to the surface on the riding continental plate. This results in active continental volcanism.

The modern-day topography of the Cascade Mountains is product of continued volcanic activities in the terrain.