G6-Glaciation and its Effects on Landscapes-1130L-04

The Impact on Florida

Since thick sheets of ice did not cover Florida, it was not directly affected by the physical changes that glaciers bring about. This does not mean that Florida was immune by any means. While the glacier’s grinding and shaping did not make it as far south as Florida, other processes were equally impactful.

The water that made up the huge glaciers had to come from somewhere, most likely from oceans and seas. According to some estimates, the amount of water contained in the glaciers during the Ice Age lowered the sea level by as much as 400 feet. During the multiple glacial advances during the last Ice Age, the water level rose and fell. At times, Florida’s landmass grew in size due to the lower sea levels. During times of glacial advance, the Florida peninsula would have been far larger than it is today and included what is now the Bahamas. From this increase in size, the region would have also been much drier, much like other areas at this same latitude. The reduced rainfall most likely lowered the water table, which may have accelerated one process that Floridians are very familiar with; springs, sinkholes and lakes.

The Florida peninsula is made of carbonate rock. Carbonate rock is prone to the forces of weathering through the process of dissolution. When slightly acidic water seeps through the cracks in the rocks, some of the rock dissolves and is carried away. Over time these voids can become large. In Florida, these large voids allow for huge amounts of water to seep into the earth.

Only at times when this carbonate rock platform is above water is it exposed to the dissolution process. Evidence of this chemical process can be found in the now submerged “blue holes” found in the Bahamas, which was once part of the Florida peninsula.

Conclusion

Florida may not have to worry about mile thick ice sheets covering its surface, but that does not mean global climate changes wouldn’t have much of an impact. During the last Ice Age, Florida was completely submerged several times during the interglacial warming periods that accompanied the four major ice advances. During the times when it was above water and its surface area increased, the climate was very dry. Clear springs, lakes and even the Florida Aquifer formed during times when the sea level was low.

As sea levels are expected to rise due to climate change over the next few decades, we can learn a lot from studying Earth’s geologic past. It also brings to mind many questions such as: if the climate was drier when the sea level dropped, what happens if it rises higher than the present levels? In fact, Florida is much more threatened by changes in climate and sea level than most other areas. By studying past events, it may help provide solutions to future events.