Florida's Barrier Islands. Florida Coastal Naturalist project

1. A GEOLOGIC HISTORY
FLORIDA’S BARRIER ISLANDS

2. http://www.fishstock.com/sites/fishstock.com/files/images/2014/03/A01N913287.jpg

3. BARRIER ISLAND FORMATION
1. Offshore bar theory
2. Spit accretion theory
3. Submergence theory
(http://coast.noaa.gov/archived/beachnourishment/html/geo/barrier.htm?redirect=301ocm)
(http://upload.wikimedia.org/wikipedia/commons/thumb/4/48/Accreting_coast_Image6.svg/360px-Accreting_coast_Image6.svg.png)

4. (USGS)
BARRIER ISLAND ANATOMY

5. http://faculty.scf.edu/rizkf/OCE1001/Images/estuarytypes.jpg
(a) Coastal plain: Chesapeake Bay- drowned river valley
(b) Fjord: Puget Sound- glaciers
(c) Bar-built: IRL Barrier Islands
(d) Tectonic: San Francisco Bay- San Andreas fault
http://en.wikipedia.org/wiki/Estuary

6. CHANGING COASTLINES
Coastline changes with sea level
and global temperatures
http://www.fnai.org/ARROW/almanac/geology/geology_history.cfm

7. CAUSES OF EARTH’S TEMPERATURE
FLUCTUATIONS
• Moving continents affect oceanic and atmospheric
circulation
• CO2 concentrations (high CO2 => high temp)
• Volcanic eruptions, extraterrestrial collisions
(dust reflects sunlight => low temp)
• Milankovitch cycles
• Eccentricity
• How elliptical the orbit is
• Axial tilt (obliquity)
• Diff btw orbital and rotational axis
• Precession- axis wobbles like a spinning top
• 26,000 year cycle
• Seasons- small scale
• Relates to tilt and not distance from sun
http://en.wikipedia.org/wiki/Milankovitch_cycles

8. http://en.wikipedia.org/wiki/Milankovitch_cycles
Circular orbit,
no eccentricity
Orbit with 0.5 eccentricity.

9. precession
obliquity
http://en.wikipedia.org/wiki/Milankovitch_cycles

10. http://www.johnenglander.net/sea-level-rise-blog/why-sea-level-will-rise-centuries-ultimately-100-feet

11. TECTONIC PLATE MOVEMENT AND
FORMATION OF FLORIDA
• Plates can move up to 10cm/yr!
• Driven by convection currents deep underground
that either create or destroy Earth’s crust
http://en.wikipedia.org/wiki/Plate_tectonics
http://www.ucmp.berkeley.edu/education/dynamic/session1/sess1_earthcurrents.html

12. http://upload.wikimedia.org/wikipedia/commons/8/8a/Plates_tect2_en.svg

13. TECTONIC PLATE MOVEMENT AND
FORMATION OF FLORIDA
• Mid Atlantic Ridge created Atlantic ocean
• Was a factor in the separation of Pangea
• Crust being created, pushed land apart, gave east
coast N. America sloping beaches, while the west
coast slides over another plate, creating cliffed
beaches
http://www.amnh.org/education/resources/rfl/web/bulletins/earth/A/6/4/A_0007_04_00_w_image1_lg.jpg

15. HOW OLD ARE FLORIDA’S
BARRIER ISLANDS?
• About 18,000 years young
• End of the Pleistocene
• Last glacial melting period
• Susceptible to frequent changes
• Human and environment influenced
http://fcit.usf.edu/florida/teacher/science/mod2/resources/changing.coastlines.pdf

16. http://tracks.roojoom.com/u/shirly-ronen-harel,60/the-geological-time-scale-explained,3979
GEOLOGIC TIME SCALE

17. HURRICANE CHARLEY EROSION

18. NSB INLET MARCH 2014