Destin Florida Vacation Condo
White Sand Beaches
Why are Destin's beaches so beautiful?
PANHANDLE BEACHES ARE BEAUTIFUL FOR THREE REASONS
When you think of the Emerald Coast, you think of its sparkling white sand. But did you ever wonder how it got that way?
Dr. William F. Tanner, a professor of geology specializing in sedimentology at Florida State University, says there are three basic reasons. The first is a lack of shell material in the sand. Such material turns the sand at most of the world's beaches a shade of tan. Tanner said there could be two reasons why the Emerald Coast's sand contains little shell; either it's not there in the first place, or it is there and just doesn't wash ashore. Although he admits much work still must be done to determine the movement of sand in Northwest Florida waters, Tanner said his diving experience has shown few bottom-dwelling animals.
"My impression is that there is just not much shell out there," he said, adding that much of what is there is fragile and is broken up and cleansed long before reaching shore.
The second reason for the sugary white beaches is that the sand is more than 99 percent quartz, Tanner said. He compared the quartz to window glass. "It is clear in solid form," he said, "but if you grind up window glass, instead of being clear, it gives the appearance of being white." Since there is less than 1 percent of darker materials, "that's not enough to give (the sand) any other color," he said.
The quartz actually came downriver from the Appalachian Mountains and eventually made its way to the Gulf of Mexico. Normally such quartz would have an iron oxide coating giving it a pink or rosy tint, Tanner said. But since the Apalachicola is the only river in Northwest Florida that drains directly into the Gulf, the heavier, coated sand ended up short of the beach. "So the brown iron-stained sand that you see on the river sandbars doesn't ever make it to the Gulf," he said. "It's trapped in the estuaries and bays like Choctawhatchee Bay." Exactly how the white quartz sand on the beaches lost its iron oxide coating is still a mystery, Tanner said. His hypothesis is that it got knocked off 20,000 to 30,000 years ago.
Mystery also surrounds the final reason for the pure white beaches: the lack of heavier, darker materials in the sand. "They're certainly up there and they certainly do start down here, but how we lose them is a good question," Tanner said. One hypothesis is that the sand from the southwestern Appalachians depositied itself some 100 million years ago as the sealine moved southward. Later maybe 60 million years ago, it picked up and moved again and the process continues. Each time the lighter sand would deposit itself in the mouths of the rivers, leaving the heavier, darker sand further upstream. Eventually, as out present-day coastline formed, the sparkling white sand found its way to the Emerald Coast.
Turner acknowledged there are more questions than answers as to why the Emerald Coast's sand is the color it is. But one thing seems sure, when you walk on the beaches, you're actually walking on the mountains.
by Steve Humphries
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