Florida: Sandbox of the U.S.?

Q: I’ve heard that Florida’s soils are pretty much all sand. Is that true? If so, how can sand be soil?

Fig. 1. The soils of Florida

A: Many folks have the impression that Florida and its soils are nothing but sand. This is only partially true. Florida actually has a rich range of soils. Each color in Fig. 1 represents a unique soil type in the state.

True, many of Florida’s soils are dominated by sand. These sandy soils are represented by the blues, greens, and purples seen in the Florida peninsula in Fig. 1. More specifically, these soils are dominated by the mineral, quartz, which gives Florida its white sand beaches.

But not all of Florida soils are dominated by sand. The Everglades area in south Florida (Fig. 2), which covers approximately 734 square miles, is dominated by organic soils. These soils are depicted by the maroon color at the southern end of the Florida peninsula in Fig. 1.

And the orange color in the panhandle of Florida indicates soils that have a considerable amount of sand at the surface but also contain a significant amount of clay. Here you will find the red clays commonly associated with Georgia.

Fig. 2. The Florida Everglades are dominated by organic soils. Photo: Kim Seng, flickr.com

Now for the second part of the question: How can sand be a soil? Well, all soils are made up of mineral materials (sand, silt, and clay), organic material (decomposing plant parts), water, and air. In other words, while sand is an important component of soils, it is not the only component that makes a soil.

The white sand you see on Florida beaches is material that was laid down by the ocean over millennia and it’s the canvas upon which Florida soils have been painted. Another question could be: Where did all that sand come from? As the mountains of the southeastern U.S. weathered, rivers carried the minerals (sand, silt, and clay) to the ocean. Ocean currents then deposited these materials under water, where the ocean worked and reworked them.

Eventually, the water of the earth was tied up in snow and ice and sea levels lowered, allowing Florida to become dry land. That is why you can often find shark’s teeth in many Florida surface deposits.

–Answered by Nick Comerford, University of Florida

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