| 词条 | Florida Platform |
| 释义 |
The Florida Platform is a flat geological feature with the emergent portion forming the Florida peninsula. StructureThe platform forms a rampart between the Gulf of Mexico and the Atlantic Ocean. The platform's western edge, or Florida Escarpment, is normally defined where water depths at {{convert|300|ft}} drop dramatically and in a short distance to {{convert|10000|ft}}. The Florida peninsula is located on the eastern side of the platform, where in places it lies only {{convert|3|to|4|mi}} from the platform's edge. On the Gulf side the platform ends over {{convert|100|mi}} to the west of the modern shoreline, where a massive cliff rises over {{convert|6000|ft}} from the {{convert|10600|ft}} depth of the Gulf floor. The western reaches of the platform just off Tampa were explored by the submersible DSV Alvin. Examination has placed the depth of carbonate rocks at greater than {{convert|20000|ft}}. GeologyBasementThe platform's basement rocks include Precambrian-Cambrian igneous rocks, Ordovician-Devonian sedimentary rocks, and Triassic-Jurassic volcanic rocks.[1] Florida's igneous and sedimentary foundation separated from what is now the African Plate when the super-continent Pangea rifted apart in the Triassic and possibly pre-Middle Jurassic. It then secured to the North American craton.[2] One of the early geologic structures is the Peninsular Arch which formed during the Jurassic. Emergent portionThe oldest sediments that are exposed are Middle Eocene carbonates found in the Avon Park Formation. Most of the state of Florida is covered by Pliocene, Pleistocene, and Holocene siliciclastic-bearing sediments deposited during sea-level fluctuations and filling in of the Gulf Trough beginning in the late Tertiary and Quaternary. Notes1. ^Arthur, J. D., 1988, Petrogenesis of Early Mesozoic tholeiite in the Florida basement and overview of Florida basement geology: Florida Geological Survey Report of Investigation 97, 39 p. 2. ^Smith, D.L., 1982, Review of the tectonic history of the Florida basement: Tectonophysics, v. 88, p. 1-22. External links
3 : Geology of Florida|Physical oceanography|Terranes |
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