Island Formation
Mackinac Island was formed around 13,000 B.C.E. as a result of glaciers beginning to melt in the region during the last Ice Age. Also during that period, the Great Lakes formed and Lake Huron along with Lake Michigan encompassed Mackinac Island (New World Encyclopedia 2014). These lakes, two of the largest lakes in the United States provide a barrier between other landmasses.
In the beginning stages of construction on the Mackinac Bridge, researchers were able to learn even more about the strata of the region. The rock deposits found in the area during construction date back to late Silurian and middle Devonian time periods, periods that range from around 400 to 419 million years ago (Melhorn 1959, 403-416). As was discussed in Niemi’s lecture at the beginning of the year, the Earth is very dynamic. The planet constantly resurfaces making it hard for researchers to find many rocks and fossils. It is absolutely possible that there are rocks older than 420 million years in this region but it’s a very challenging task. The somewhat rare rock formation of the region is relatively unknown as to the cause but consists of limestone and halite (rock salt). The general belief is that as the rock salt dissolved, it made the limestone pieces collapse and created solid rocks that are now known as the Mackinac Breccia. While the Great Lakes were forming, the limestone bedrock began to wear down and created various rock formations and cliffs that are still major attractions today on Mackinac Island. Researchers have discovered that between 10,000-12,000 years ago there were different lake levels than the current one today and these previous levels were in fact higher than the current one. A 1941 study suggests that only the peak of the Island was free from water at one point in time (Potzger 1941, 298-323). An example of one these rock formations is the popular tourist attraction, Arch Rock. The rock is about 50 feet wide and 146 feet above the water. The rock is made up of limestone and shale that was formed by glaciers from the last Ice Age (Mackinac Parks 2015). These rock formations and cliffs were paramount for early European settlers and military forces because the island proved to be a great strategic location. To learn more about the various battles that took place on the island click here. |
Another key part of the geographical discussion is how the physical features of the island affect human activity and how the population, resources, industries, and land use tie together. Today, the geography and wildlife of the island cater to the thriving tourism industry that is without a doubt the largest industry on the island. Thousands of people come every summer to eat fudge, look at attractions, and take in the wildlife. However, more than half of the island still remains in its natural environment and no hunting is allowed as it has been designated a State Historic Park. In an interview with Francis Blouin, he noted that in the past (1850-1920) the lumber industry in northern Michigan was booming but Mackinac Island was not involved in this industry. The reasoning behind this is because Mackinac Island is so small it wasn't worth anyones time to deforest. This in turn allowed for the island to remain natural and become a major tourist attraction in the future (Blouin, 2015). The relatively cold climate restricts human activity throughout the winter months and due to a ferry being the most commonly used way to get to the island it relies on good weather. The local governments main purpose is to keep the island in its natural environment. Another key issue to the island and one that was discussed by Stephen Smith in lecture was natural selection. With the island being relatively small there must be some struggle for resources. Coupled with increasing numbers of various species, along with the increasing population of humans, natural selection must be a real challenge on the island as animals are always in competition for resources. Everyone on the island is committed to keeping the island as natural as possible and while it is a huge tourist attraction the island is still respected.