FL Sands (Sanibel -- Blind Pass & Ft Myers Beach) EarthCache
FL Sands (Sanibel -- Blind Pass & Ft Myers Beach)
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Difficulty:
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Terrain:
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Size: 
(other)
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As an earthcache, there is no “box” or “container” to discover. Rather, with this cache, you discover something about the geology of the area. For more info, consult www.earthcache.org
This earthcache was created to give you a primarily geological earthcache (instead of primarily hydrological as most of the earthcaches in the area are).
Logging Requirements are listed first, primarily for paperless cachers.
Congrads to Pilot_Searcher for FTF (First to Finish Logging Requirements)!
Process Requirements:
You need to WORK WITH a couple of TABLESPOONS worth of sand from each of the two beaches. I would suggest that you take a hand magnifying glass, the sizing chart image, and 2 cups of white vinegar with you so you can successfully interact with the logging requirements. You should interact with the sand from a similar spot on both beaches (ex. work with both samples from above the hi-tide/hi-surf line).
Logging Requirements:
- (Hint: Take a pinch of sand from each location and sprinkle it on the sticky side of a piece of tape. Tape the sample to a dark piece of paper.)Which beach has the finest grain of sand? based on wave size and island orientation (east-west or north-south) evaluate WHY one type of sand is excessively finer than the other
- Which sand sample had the highest SILICA content? Why? (See description)
- How angular is the sand at each location? That is, have the sand grains been traveled by wind or water long distances or only a short distance?
- FOR EACH BEACH SAMPLE: Take 1 Tablespoon sand and dissolve it into 1 cup white vinegar. Which beach sand bubbles? As a rule, the vinegar reacts with calcium (bones/skeletal remains) and thus is a great litmus test for which sands are composed primarily of Silica (no bubbles) versus those composed primarily of calcium sources (shells/coral) (See Calcium/life description below) Vinegar is all-natural and biodegradeable ;)
Pictures are always appreciated but never required
Locations:
1. Fort Myers Beach near fishing piers (bridge free, beach parking fee)
2. Sanibel -- Blind Pass (bridge fee & beach parking fee)
The locations are only six LOS miles apart, but you should probably plan to do this along with other caches or beach experiences to make it worth the fees. There are quite a few caches in both areas. I suggest off season OR early hours, especially on Fort Myers Beach, where parking is a premium.
I initially thought of taking you to FOUR beaches, along the Gulf Coast, that show dramatically different types of sand, but the drive and fees seemed to be more prohibitive than one smiley warrented.
Parking:
I have included parking coordinates for Sanibel -- Blind Pass. Three other parking lots on the island use the same General Parking Receipt Link .
Fort Myers Beach (the island) has more parking, but no coordinated system. There is a private pay lot near the Ft Myers Beach coords, as well as metered street parking. I read about free parking under the Mantanzas bridge (and a trolley for 25 cents to any of the beaches) but I have not used this system Link
Geological Summary:
The sands of Florida are many and diverse. The Gulf Coast has a variety of superbly white beaches, composed primarily of SILICA -- quartz crystals. One of its best qualities is that it is so reflective that it doesn't get hot, even under the most intense summer sun! Other beaches in Florida have black sand (Venice), others have colorful shell-filled beaches (various), orange/pink beaches (Siesta Key), and brown textured beaches (Daytona).
"Much of the sand on Florida beaches is made up of quartz crystals produced by the weathering of continental land masses like the Appalachian mountains. The quartz is washed down America's great rivers into the Atlantic and the Gulf of Mexico where it is carried onto the beaches by water currents and waves.
Combined with the sparkling quartz crystals may be shell fragments and coral, limestone, trace minerals, fossils and organic matter, which lend different colors to the sand. Beach sand along the southeast Florida coast and the Keys is often composed more of coral and mollusk shell fragments than of quartz crystals." (VisitFlorida.com) Link
Sand Sources:
Sand comes primarily in two categories: SILICA and CALCIUM (ARAGONITE). SILICA-BASED sands are those composed primarily of geological sources such as balsaltic rocks, quartz, and other minerals. Of course, in most cases, there are not simply rock grains in the sand on a beach. Beach sands with a high CALCIUM content contain remnants of life, in at least one of two categories: mono-cellular to multi-cellular microscopic “shell-like” creatures or monopod and gastropods (shells in the typical sense of the word). All of these living organisms have a calcium-based bone structure, which can be absorbed / broken down with vinegar (it bubbles and eventually dissolves) (Wikipedia.com).
Island Geography & geology:
- Sanibel -- There are at least four public access beaches, three of which are along the Gulf side of the island. Sanibel is a barrier island, but differs dramatically from the vast majority of barrier islands in that it is oriented east-west whereas most of the islands hug the coast in a north-south orientation. As a result, waves traveling from the south hit the island directly rather than "sideways." The underwater "shelf" where sediment has been deposited by the waves is long and wide. This same characteristic has made Sanibel one of the best shelling beaches in the world, since the ocean storms (especially hurricanes) come from the south and deposit the shells from that underwater shelf on the beaches of Sanibel on a regular basis. I have shelled this beach when the pile of shells was 7' tall and over 300' long -- I simply sat on the top of the stack and started being a very picky shell collector!
- Fort Myers Beach near the fishing piers is on the north-south barrier island known as Estero Island, and boasts the Annual Sand-sculpting Championship Festival. The angular sands that "catch" each other in a puzzle-like fashion (on a microscopic level) allow sculpters to create masterpieces. Also, the reflective crystals keep the heat from building up in the sand. This helps keep the sand cool and damp long-term -- both aids for the festival and a pleasure for the feet.
Size differentiation: Chart:
Sand is considered geologically as any soil particle between .063mm and 2.0 mm in size. "In the United States, sand is commonly divided into five sub-categories based on size: very fine sand (1/10 mm diameter), fine sand (1/4 mm), medium sand (1/2 mm), coarse sand (1 mm), and very coarse sand (1 mm – 2 mm). You can use the embedded image to figure out which size of sand exists on each beach. Yes, there is a variation, but you might be suprised it is to categorize it, especially if you use the sand sprinkled on tape method!
Sources for sand in Florida:
Sand in Florida comes from a variety of sources.
- Limestone inland (eroded from the rivers)
- Quartz from the Appalachian Mountains (eroded from the rivers)
- Remains of microscopic and shell creatures
- Coral
Sand Deposition & Composition:
Sand is transported by wind or water and deposited in the form of beaches, dunes, and sand bars.
The study of individual grains can reveal much historical and geological information as to the origin and kind of transport of the grain. Quartz sand that is RECENTLY weathered from larger rocks will be angular and be of drastically different sizes. It will feel rough to the touch. By contrast, sand that is transported long distances by water or wind will be rounded. Of course, if beach sand also contains shells or other CALCIUM-based components, the distance traveled will be much less, but the ferocity of the waves will be able to be gauged by the size of the shell fragments.
Resources
Wikipedia "Sand" Link
Beach Hunter.net Link
Vinegar Test Recipe Reef Cetral.com Forums Link
ScienceKidsatHome.com Link
VisitFlorida.com Link
Additional Hints
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