
13.5 How and where do mountains form?
Fig 13.19
We have several coincidental processes occurring as shown below. 1) Volume is added by plutonic processes that are 10x the volcanic processes atop. 2) Crust thickens during shortening by plastic flow due to compression. This occurs in the hotter areas because hot rocks flow more easily. Thus the mountains build up over the hotter regions, rather than close to the trench where compression is higher.