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Florida’s Geology

Florida’s Geology. The physical materials of Florida Week of January 13, 2014. Geology = . Geo- , Latin for earth. = Why study it for Florida Ecology?. Geologic Time. Florida Broke to the surface as land 35 to 25 million years ago ( mya )

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Florida’s Geology

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  1. Florida’s Geology The physical materials of Florida Week of January 13, 2014

  2. Geology = Geo- , Latin for earth. = Why study it for Florida Ecology?

  3. Geologic Time • Florida Broke to the surface as land 35 to 25 million years ago (mya) • The bedrock of Florida accumulated for millions of years

  4. Building a Foundation • Pangea = a supercontinent (~550mya) and the separation of the continents through continental drift. • Florida’s limestone bedrock was attached to Africa, in a rift, then pulled apart with the North American continent.

  5. Evidence for Pangea • Same rocks and sediments and fossil deposits containing same species discovered on separate continents---separated by Atlantic Ocean • Continents appear to “fit together like puzzle pieces”

  6. How did Pangea break apart? • Theory of Continental Drift, 1950’s and 60’s. • Earth crust made up of many “plates” • The boundaries where ocean plates meet are mid-ocean ridges. • New sea floor created here. • Other plate boundaries responsible for volcanoes, earthquakes, mountain building

  7. Evidence for Continental Drift • Young sea floor (at a ridge) had little time to accumulate sediments • Rocks are older and sediment is thicker as you move away from the ridge • The rocks of the sea floor show the earth’s magnetism at the time of their cooling = magnetic anomalies.

  8. Florida as Africa • Florida’s limestone bedrock was attached to Africa, in a rift, then pulled apart with the North American continent. • Florida's Movement

  9. Major Eras in the Natural History of Earth 1) Paleozoic: 550-250 mya • Early Animal Life in the Oceans • Fishes Diversify • Ferns and Early plants begin to colonize land 2) Meozoic: (250 to 65 mya) • Reptiles Diversify, Age of Dinosaurs • Gymnosperm Plants = most softwoods with seeds in cones diversify 3) Cenozoic :(65 mya to Present) • Mammals diversify • Flowering plants =Angiosperms, Harwoods Diversify • Florida Emerges as a LANDMASS

  10. Cenozoic Era: 65 mya to Present • Tertiary Period • Paleocene 65-53 mya • Eocene 53-34 mya • Oligocene 34-23 mya (Florida Emerges at end here) • Miocene 23-5 mya • Pliocene 5-2 mya • Quarternary Period • Pleistocene Epoch 2mya to 10,000 years ago • Holocene (Recent) 10,000 years ago to present

  11. Florida as a Landmass • Earlier shorelines determined by looking at fossils in marine deposits • Florida has changed size in the past 35 million years • High sea level/Interglacial warmer climate = island chains • Low sea level/Ice ages = twice the present landmass • Panhandle emerged ~25 mya • Last time peninsula underwater 23 mya

  12. Florida Platform-limestone dominated flat topped structure • 3 components of Platform • Basement rock-Paleozoic & some Mesozoic • Carbonate rock- Mesozoic & Cenozoic era • Siliciclastic sediments (mostly quartz sand)-Cenozoic era 1) and partially 2) when still part of Gondwana (Africa)

  13. Paleocene and Miocene 65-34 mya

  14. Paleocene and Miocene 65-34 mya • Many fossils from this time period are found: • Sea grass fossils • - • - • - • -

  15. Oligocene 34-23 myaLate Oligocene 25-23 mya • FL many islands before complete emergence Late Oligocene: • Sea level fell ~ 300 ft. • Florida Emerges ~ 24 mya. • Gulf Trough a narrow inlet or estuary, but filling in • Fossils from this time period:

  16. Oligocene 34-23 mya • Insects, bats, birds, tortoise • Land Mammals • (Beaver, deer, rodent, rabbit, anteater, goat, horse, pig) like creatures • Opposum • Saber-toothed cats

  17. Oligocene 34-23 mya Read and record about Oligocene

  18. Miocene 23-5 mya • Gulf Trough filled in • Parts of FL repeatedly submerged and exposed • Freshwater communities emerging • Diverse Animals:

  19. Miocene 23-5 mya Read and record about Miocene

  20. Pliocene 5-2mya • Inter-glacial Period, Warm Climate • High Sea Level • North American continent is dry • FL has enough water resources to support Mammal Diversity on semi-arid savannahs and subtropical forests

  21. Pliocene Megafauna • Horse • Camelid • Glyptodont • Sloth • Mammoth • Mastodon • Giraffoid • Rhinoceroid • Long nosed Peccaries

  22. Megalonyxjeffersoni • Giant ground sloths • 8-10 feet, up to 800 lbs • Vegetarian, Foraged on trees.

  23. Mammuthus- Wooly Mammoth Mammut- American Mastodon

  24. Pleistocene 2mya to 10,000 ybp • Many of these same animals went extinct in the late Pleistocene. • Another ice age occurred, Colder climate • Low sea level • A landbridge between N and S. America forms allowing for long isolated species to travel North and South. • The Great American Biotic Interchange

  25. The Great American Biotic Interchange…During Late Pliocene/Early Pleistocene… From South America From North America • Opossum • Armadillo • Flying Squirrel • Vampire Bats • Lots of Frogs • Hummingbirds • Raccoon • Llama • Coral Snakes • Many Pit Vipers • Jaguar

  26. Formation of the Gulf Stream • Remember: Ice Age, Low Sea Level, Central America Appearing…. • Blocked Pacific from the Atlantic • Diverted Ocean Currents • Gulf Stream created! • Altered Climate • Warm air and water moving to poles, cooled to make precipitation, creating much more snow and ice. Ice caps grew and repeated Ice Ages.

  27. Coral Reef Formation around Florida • Gulf Stream also took away nutrients from the warm waters, making ideal conditions for coral reefs to become established. • Evolution of Staghorn and Elkhorn Coral Species

  28. Pleistocene continues • The Bering land bridge was also exposed during these global ice ages, allowing Asian species to migrate to North America. • Long-horned Bison

  29. Holocene Period • ~20,000 years ago to Present • Periods of warming and cooling continue on a smaller scale • Humans arrive to N. America via Bering Land Bridge • Most mammal megafauna extinct, due to:

  30. Southeastern U.S Coastal Plain • Florida a part of this region. • Area of sediments that spreads from the southern Appalachian Mtns. Piedmont to the coasts • Piedmont = a rocky skirt that surrounds mountains

  31. Florida: 3 layers of sediments • Sediments = loose materials deposited on the land or at the bottoms of water bodies • Fragments of rocks from land • Materials formed beneath the sea • Organic matter

  32. Florida’s BedrockBottom layer: Marine sediments • Build-up of ancient marine sediments • Originate from salts, dead organisms with shells that settle out of ocean waters • Florida’s major ones: • Limestone & Dolomite • Calcium carbonate and Magnesium carbonates

  33. Middle Layer: Clastic Sediments • Loose Clastic sediments • Fragments of rock • Mostly Quartz (Silicon Dioxide SiO2) and Feldspar (Aluminum Silicates AlSi#O#) • From erosion of Appalachian Mtns. • In form of clay, silt, sand, gravel

  34. Top layer: Soil=particulate material lying a lop land, which is capable of supporting plant life. • Mixture of Marine and Clastic Sediments with Organic Materials • Vary in Size of sediments • Vary in pH from Acidic to Alkaline • Vary in ability to retain water • Xeric • Mesic • Hydric 300 types of soils in Florida contribute to the diversity of our ecosystems.

  35. Soil Types • Xeric • Dry Soils • Rain water drains rapidly • Contains ample oxygen to meet plants needs • Mesic • Moist soils that do not become waterlogged • Drain well and hold oxygen • Hydric • Wet soils, may becomes waterlogged • Low oxygen concentrations

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