Denali Plate Tectonic Movements

Denali, formerly known as Mt. McKinley, resides in Alaska and is currently the tallest mountain in North America standing at a height of 20,310 feet. There are a few reasons for why this mountain has achieved this status. The three main focal points in this report revolve around tectonic plate subduction, uplift around the Denali fault, and the rock composition of the mountain. The combination of these three forces are integral reasons for why the mountain has been able to grow to its size and why it’s been able to maintain its height. To understand how subduction has affected Denali and the Alaska mountain range, you first need to understand how plate tectonics work. The theory of plate tectonics centers on the idea that the Earth’s crust
As a result, the mantle becomes less dense and will gradually rise closer to the lithosphere. The cooler, denser mantle then begins to subduct back down closer to the mantle thus replacing the rising, less dense mantle. This process of events creates a convection cycle throughout the mantle. This rotating movement causes the lithospheric plates to move.
The significance of tectonic movements directly impacts Denali through the subduction process of the Pacific Plate underneath the North American Plate which contains Alaska’s mainland. Where these two meet, the Pacific Plate subducts beneath due to oceanic plates having a higher density. Because of past plate collisions, terranes are carried by the Pacific Plate and become accreted together with the North American Plate to form suture zones. These zones are weaker due to the fact that the terranes are broken remnants of continental collisions.
Uplift around the Denali Fault is a direct result of these suture zones. The forces of plate subduction in the area creates extreme compressional stress. After the stress reaches a certain threshold, seismic activity results in the form of earthquakes. Since the suture zones are weaker areas, these rocks become the first ones to deform. A large bend along the fault causes the rocks to bunch together under seismic activity. Denali is located on this bend which helps explain why the mountain has been able to grow to its monumental
This process started 56 million years ago during the Paleocene which occurred in the Cenozoic Era. During this time, magma began to cool beneath Earth’s surface to form an igneous pluton made predominantly of granite. Throughout this time frame, this large mass, otherwise known as a batholith, was uplifted through Earth’s surface to the standing height that it is today. Due to Denali being composed primarily of granite, it has been able to withstand the forces of erosion. This is even more impressive considering the fact that 75% of the mountain is covered by snow and ice. This has allowed Denali to maintain its shape and ability to grow faster than it erodes.
Denali has been able to grow to become the largest mountain in North America through a combination of factors. The subduction of the Pacific Plate has created suture zones which enable the process of uplift to occur more rapidly. This is also aided by the compressional forces brought along by subduction which is released along the Denali Fault. Lastly, Denali’s granite composition has allowed the mountain to resist erosion. In conclusion, Denali has a unique combination of factors and elements which have worked together to form this spectacular mountain that we see