![]() ![]() This Key Largo limestone formation was due to deep oceanic seas that covered the area over 125,000 years ago. The Windley Key Geological State Park is formed of Key Largo Limestone as well as fossilized coral. Day 2 Windley Key State Park (Saturday, September, 21st) This entry was posted in Uncategorized on Novemby kavaryr. This picture shows dissolution occurring in the Miami Oolitic limestone. ![]() Apart from the cool geology of the area there was an alligator that has been living in the Blue Hole for many years, that I can only assume wanted to be our friend. This was caused by dissolution occurring on the surface. ![]() Like the Key Largo limestone through various stages of digenesis, the rocks become more porous and permeable which is a main component of carbonate environments. These consisted if some fossiliferous corals but the ooids were most dominant. Bryozoan facies were also present though very miniscule. When walking along the area of the Blue Hole, around the lake as well as the surface of the ground had visible ooids and oolites that were well sorted amongst some quartz sand and marine fossils and corals. In the past, this area served as a quarry. This limestone formation is formed due to a previous shallow lagoon environment and like the Key Largo limestone it is a Pleistocene marine limestone. The Blue Hole (more like Brown Hole), is the only freshwater lake in the Keys and host the Miami Limestone (Miami Oolite). Day 2 Blue Hole on Big Pine Key (Saturday, September, 21st) The Penicillus has a long stalk that can get up to about 10cm and a bushy ball for a head.Ĭlassmates at Veteran Beach collecting samples of Halimeda and Penicillus ![]() The green algal body of the Halimeda consisted of calcified green segments and the Penicillus which basically looks like a horrendous tasting lollipop. It’s certainly cool for me at least to think that these plants through their Calcium Carbonate (CaCO 3) deposits, account for almost 50% of the tropical beach sand!! Snorkeling out to collect samples proved a little difficult at first with all the well camouflaged upside down jelly fish around, but after only one sting (others got stung a lot) I got my samples. These types of plants are found in low energy environments and they were the early colonizers of tropical habitats. Still on Day 2 (we had a lot of fun stops on this day!), after the Big Pine Key was Snorkel time, as well as collecting samples of Green Algae, the Halimeda and Penicillus. Microscopic images of the Miami (Oolitic) Limestone and the Key Largo Limestone respectively Thin sections of the Key Largo Limestone and the Miami (Oolitic) Limestone respectively. When dried, they were cut down and vigorously grounded so that the grains in the sample were clearly visible under the microscope. The billets were then stuck to the slides using epoxy and left overnight to dry in the oven. These billets were then sanded down using grit to make the surface smoother. To make the thin sections, the rock samples were first cut using a giant electric saw to make sizable billets. Within the matrix there are also some quartz present. These layers are visible through the presence of ring like bands around the center grain. The Miami limestone, an Oolitic Limestone (grainstone) has layers of calcite deposit around sand grains or shell fragments. There is generally a crystalline matrix composed of calcite that are found between the grains. The grain sizes are fine and moderately sorted and its composition comes from the deposition of carbonate from various fossils, corals and algae as described in the blog. The Key Largo Limestone is composed mainly of calcium carbonate (CaCO3) deposits that make up the majority of its composition. ![]()
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