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The Geology of Florida1Basement rocks were detached from the African Plate when the Pangaea rifted and had moved closer to the North American Plate.The formation of carbonates was critical which was caused by the sinking of basement rocksFlorida Platform was created during the Cretaceous PeriodSiliciclastic sediments were introduced during the erosion of Appalachian HighlandsInterglacial and glacial events during the Quaternary Period, sea level changes, deposition, erosion, and the formation of the modern topography occurred. .Geological Events2The following were notable geological events. Basement rocks were detached from the African Plate when the Pangaea rifted and had moved closer to the North American Plate. Consequently, carbonate rocks were formed in the basin due to the sinking of basement rocks. During the Cretaceous Period, the Florida Platform was created. Then, when the Appalachian Highlands was eroded, siliciclastic deposits were introduced onto the Florida Platform. Throughout time, especially at the time of interglacial and glacial events during the Quaternary Period, sea level changes, deposition, erosion, and the formation of the modern topography occurred. Florida PlatformBasement rocks are part of African PlateCarbonate sedimentation from mid-Jurassic to mid-OligoceneSiliciclastic sedimentation Pliocene to HoloceneGeological Feature

3Approximately 350 miles wide at its broadest point and 450 miles long, the Florida Platform is located in the south-central part of the North American Plate. The exposed part of the Florida Platform is what we now know as the modern Florida. According to T. Scott, et al. (2001), during the mid-Jurassic to mid-Oligocene Periods, this platform a was formed by carbonate sedimentation. Also, during the Pliocene to present times, siliciclastic sedimentation has to the formation of the Florida platform. Radioactivity studies help determine Absolute age.Correlation of rock units between using fossils determine the relative age.Geologic Time4According to The Department of Environmental Protection, radiometric dating processes have been used to date basement and sedimentary rocks that contain uranium while fossil assemblages has been utilized to determine the relative ages of rock units. Florida was part of African PlatePangaea 230 million years ago (top left)Triassic Period 195 million years ago (top right)Cretaceous Period 65 million years ago (bottom)

Plate Tectonics

5T. Scott, et al (2001) notes that Florida Platform s basement rocks were part of the African Plate once. However, when Pangaea separated during the Triassic Period, these rocks were sewn to the North American plate. The figures on the slide show Florida (in red) as the plates move away from each other. Sea level variations during Cenozoic and Quaternary Periods led to stages of non-deposition, weathering, and erosion.Siliciclastic sediments were brought and were eroded from Appalachian Highlands over the Florida Platform during mid-Cenozoic to late Paleocene.Weathering and Erosion6Approximately 1.8 million years ago to present, during the Quaternary Period, sea level had fluctuations caused by glacial and interglacial periods. Such has shaped the present topography, a result of weathering and erosion. At the peak of the interglacial periods in the Pleistocene, sea levels would have been about 150 feet higher than the current sea levels. With this, Florida would just have been islands. At this time, sediments would have spread over the Florida Platform. When the water withdrew, the erosion of the deposited sands occurred and resulted in large-scale sand ridges that are still present at the central area of the modern state. According to Lane (2004), when the sea level was at lowest which happened during the glacial times, exposed carbonate rocks weathered and structures such as sinkholes, dissolution valleys, and collapse depressions were made from the dissolution or chemical weathering of limestone.

Sea level fluctuated during the Cenozoic Era which was several hundred feet either above or below the current levels. These variations are recorded by the abnormalities seen in the stratigraphic column. (Lane, 1994).

A time of extreme uplift and erosion that happened during the mid-Cenozoic to late Paleocene to the Appalachian Mountains. Before this time, the eroded material was prevented by the Gulf Trough from reaching the Florida Platform. Consequently, large volumes of sediment filled the Gulf Trough and in time, the sediments reached the Platform. Even though the weathering and erosion did not happen in Florida, the state was directly affected by the weathering and erosion of the north (Lane, 1994).LimestoneDolomiteInterbedded with sand, silt, claySedimentary Rocks

7In the northern part of the state and in the central panhandle, basement rocks made of sedimentary rocks from the Ordovician to Devonian period can be found. These rocks comprise of sandstone, siltstone, and shale. The fossil content of these rocks has determined their ages. According to Lane (1994), the rocks visible in Florida are sedimentary rocks of which limestone and dolomite are the predominant ones. The carbonates more often than not are inter bedded with sand, silt, and clay which is the result from the siliciclastic sediments from the erosion of the Appalachians and sea level fluctuations.Basement RocksPre-Cambrian to Cambrian igneous rocks (granite)Central FloridaTriassic to Jurassic volcanic rocksNorth FloridaMesozoic volcanic (basalt) rocksSouth FloridaIgneous & Metamorphic Rocks

8In Florida, basement rocks is either igneous and metamorphic rocks only. According to Scott, et al (2001) these rocks were once part of the African Plate. It comprises the Pre-Cambrian to Cambrian igneous and metamorphic rocks, Triassic to Jurassic as well as Mesozoic volcanic rocks. In the central part of the state, granite with a small amount of metamorphic rocks can be found. Through radiometric dating, Lane (1994) illustrated that granites age in Central Florida e was about 550 million years old. The samples were taken at more than 9000ca feet deep. On the other hand, Lane (1994) noted that basaltic rocks can be found in South Florida and in the panhandle. Water FeaturesEvergladesLargest subtropical wilderness in U.S.Unique fauna & floraNational ParkWorld Heritage SiteLake Okeechobee730 sq. miles2nd largest lake in continental U.S.Headwaters of EvergladesUsed for commercial fishing, drinking water, and irrigation

9In the United States, the Everglades is the leading subtropical wilderness. According to NPS (2009), it comprises a unique fauna and flora that cannot be seen anywhere else. The Everglades has been declared as a national park and also a World Heritage Site. SFWMD (2009) noted that the original Everglades area was much bigger, about 7.3 million acres which has been converted for human usage. The headwaters of the Everglades called Lake Okeechobee is the second biggest lake in the mainland United States next to Lake Michigan according to SFWMD (2009). It also emphasized that the lake is quite important particularly as valuable for commercial fishing, and drinking water resources, and has provided irrigation for the wide-ranging agricultural activities around the lake. PhosphateClayLimestoneDolomiteCoquinaSand and GravelOil and GasHeavy MineralsPeatResources

10Florida has several important resources. This includes phosphate, clay, limestone, dolomite, coquina, sand and gravel, oil and gas, heavy minerals, and peat. In Florida, the phosphate industry ranks third behind tourism and agriculture. According to FIPR (2004), the phosphate was deposited during the Neocene era under extraordinary conditions. At the end of year 2001, approximately 300,000 acres of land had been extracted in Florida, particularly in Polk, Manatee, and Hardee counties.I have chosen Florida for this presentation because of its distinctive geologic history that is different from the rest of the North American Plate. Also, considering that I do live in a place where there is a cold winter, it would be great to visit such a very nice warm place!Conclusion11ReferencesFlorida Institute of Phosphate Research (FIPR), (2004). Phosphate Primer. Retrieved from http://www1.fipr.state.fl.us/PhosphatePrimer/0/AE4CF5150A93866485256F800079933B Lane, E., (1994). Floridas Geologic History and Geological Resources. Tallahassee: Florida Geological Survey. Retrieved onScott, T., Campbell, K., Rupert, F., Arthur, J., Missimer, T., Lloyd, J., Yon, W., Duncan, J., (2001). Geologic Map of the State of Florida. FGS Open File Report No. 80. Retrieved onSouth Florida Water Management District (SFWMD), (2009). Lake Okeechobee. Retrieved from http://www.sfwmd.gov/portal/page/portal/pg_grp_sfwmd_koe/pg_sfwmd_koe_lakeokeechobeeDepartment of Environmental Protection (N/A) The Geological Time Scale from http://www.dep.state.fl.us/geology/geologictopics/rocks/time_scale.htm12