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Age of the Seafloor
Transcript of Age of the Seafloor
By Ashley Sebastian, Mollie Pedigo,
Elva Sarai Gutierrez, Robert Minnix
The youngest areas of the seafloor are located along the mid-atlantic ridge which consists of divergent boundaries. The data helps to understand what is happening at the plate boundaries, since divergent boundaries are moving away from one another it reveals the newest or youngest magnetic stripping on the seafloor which helps geologists date the age of the seafloor.
Some of the oldest areas of the seafloor are located against the continents, due to transform boundaries pushing the old floor along the continents. The data helps explain transform boundaries, since we know that these plates move along side one another essentially just pushing the old floor against coastline rather than causing it to overlap the coast or vice versa.
Middle age areas of the seafloor are located behind the convergent plate boundaries. The data helps understand what is happening at the plate boundaries since it helps explain that as the convergent boundaries plate pushes into another it squishes all the middle age seafloor in between two plates.
Examples of both transform and convergent boundaries can be seen in the map.
Map: Age of the oceanic lithosphere. Perzi. Accessed 12 Feb. 2015. http://commons.wikimedia.org/wiki/File:Age_of_oceanic_lithosphere.jpg
Nelson, Prof. Stephen A. "Continental Drift, Sea Floor Spreading and Plate Tectonics." Tulane University (16-Jan-2012): n. pag. Web. 12 Feb. 2015. <http://www.tulane.edu/~sanelson/eens1110/pltect.htm>.
Age of the Seafloors
Definition: According to the Cambridge Online Dictionary, topography is a "graphic representation of the surface features of a place or region on a map, including their relative positions and elevations" (Cambridge Online Dictionary). Based on this definition it is easy to see examples of topography on maps such as this one, which can help explain the age of the seafloor and plate boundaries.
Age of the Seafloor
The data for the age of the seafloor represents oceanic crust that has hardened after cooling, thus keeping magnetic stripping, which help scientists tell the age of the seafloor. Since the magnetic field is apparent after the oceanic plates come apart it reveals that the older the field is the farther away it is from the mid-ocean ridge
"How Do We Know the Age of the Seafloor? | Geology | Earth Observatory of Singapore." How Do We Know the Age of the Seafloor? | Geology | Earth Observatory of Singapore. Earth Observatory of Singapore, n.d. Web. 13 Feb. 2015. <http://www.earthobservatory.sg/faq-on-earth-sciences/how-do-we-know-age-seafloor-0>.
South America Plate
Juan de Fluca Plate
Global Seismicity (Mollie Pedigo's Slide)
One of the main factors in the plate tectonic theory. It is the distribution of earthquakes by latitude and longitude geography, magnitude, and depth ("Global Seismicity", n.d.) There are convergent, divergent, and transform plate boundaries.
Two types of plate boundaries-Subduction and collision. Subduction: When the crust of one plate is pushed down underneath the crust of another plate. Collision: Separates two continental plates that are pushed into contact ("Earthquakes and Plate Tectonics", n.d.). Earthquakes in the collision boundary define the shallow, wide zones of the earthquake activity that are in the fault systems in the collision zones.
In this plate boundary, the crustal plates are moving away from one another. This usually is seen at the mid-oceanic ridges. There are valleys that form at the ridges. The earthquakes occur at the normal faults along the sides of the rifts or underneath the rifts ("Evolving Earth", 2006)
In this type of boundary, earthquakes initially occur at the transform fault or in the parallel strike-slip faults ("Evolving Earth", 2006). The plates are sliding past one another in this boundary. Earthquakes that occur in this type of boundary possibly happen due to the friction in the fault system being overpowered and the plates suddenly move ("Evolving Earth", 2006).
Earthquakes and Plate Tectonics. (n.d.). Retrieved February 11, 2015, from http://www.cliffsnotes.com/sciences/geology/earthquakes/earthquakes-and-plate-tectonics
Evolving Earth: Plate Tectonics. (2006, October 9). Retrieved February 11, 2015, from http://www.globalchange.umich.edu/globalchange
Global Seismicity. (n.d.). Retrieved February 11, 2015, from http://geophysics.ou.edu/solid_earth/notes/seismicity.html
Graphics retrieved from:
World Seismicity graphic: http://earthquake.usgs.gov/earthquakes/world/seismicity_maps/
Divergent Boundary graphic: academic.brooklyn.cuny.edu
World Seismicity 1900-2013
So, what exactly is Bathymetry and why is it
important for us to utilize while studying
Bathymetry is the "topography" of the underwater
world. Mapping the depths and contours of the beds
of bodies of water also helps to give us a better sense of where plate boundaries are beneath the waters surface. As shown in the graphic below, you can see a number of the plate divisions throughout the world highlighted as a light or white tract of color through the usually deep blue of the ocean. These tracts represent the deepest portions of the ocean floor where plates converge to create underwater ridges or diverge to create new ocean floor as mentioned before.
"Bathymetry", NOAA, Web, 2015, http://oceanservice.noaa.gov/facts/bathymetry.html ; Image from WorldMapsOnline
Image retrieved from: brittanica.com
Topography of the Earth (Mollie)
-In the image above, the yellow lines represent the spreading zones on the mid-oceanic ridges which are the divergent plate boundaries, the deep sea trenches which are the convergent plate boundaries, and the seafloor fracture areas which are located on the transform boundaries (Alden, n.d.).
Retrieved from: geology.about.com
Alden, A. (n.d.). Plate-Tectonic Features and Global Topography. Retrieved February 14, 2015, from http://geology.about.com/od/platetectonicmaps/ss/Tectonic-Plates-And-Topography.htm
An volcanoes is the opening for the earth's crust which allows melted rock from the mantle to flow out to the surface as lava or magma.
2) a description of the distribution of the data with respect to plate boundaries:
Volcanoes are related to the convergent plate boundaries, divergent plate boundaries and hot spots. These plates, California has all of them but there seems to be no volcanic activity.
It also seems volcanoes are made out of subduction zones.
3) a description of how the data help to understand what is happening at the plate boundaries:
Volcanoes are located on or close to plate boundaries. Therefore understanding volcanoes, it would give us an understanding in a detail cross-sections showing how "plates are thin at spreading ridges, and that subduction extends long distances, taking plates deep beneath the continents."
how the data help us understand convergent, divergent or transform boundaries and how the data have helped us understand plate tectonics.
Each of these characteristics make a difference in how an earthquake/volcanoes take place. This is depending also what type of crust is occurring in; oceanic or continental.
Can you tell what type of boundary this is?
Map: unknown.prezi.n.d.Retreived February 14, 2015
Egger, Anne, PH.d. "Visionlearning.com." Visionlearning. N.p., n.d. Web. 15 Feb. 2015.
Lynch, David K. "Volcanoes and Their Relation to Plate Tectonics." Volcanoes and Their Relation to Plate Tectonics. N.p., 2009. Web. 13 Feb. 2015.