1. The physical materials of Florida Week of January 12, 2015
Florida’s Geology
The physical materials of Florida
Week of January 12, 2015

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: 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 mya
Eocene mya
Oligocene mya (Florida Emerges at end here)
Miocene 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)

14. Paleocene and Miocene 65-34 mya

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

16. Oligocene 34-23 mya Late 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:

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

18. Oligocene mya
Read and record about Oligocene

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

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

21. 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

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

23. Megalonyx jeffersoni Giant ground sloths 8-10 feet, up to 800 lbs
Vegetarian, Foraged on trees.

24. Mammuthus- Wooly Mammoth
Mammut- American Mastodon

25. 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

26. 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

27. 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.

28. 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

29. 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

30. 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:

32. 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

33. 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

34. Florida’s Bedrock Bottom 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

35. 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

36. 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.

37. Soil Types Xeric Mesic Hydric 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