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Global Plate Tectonics: The Unifying Model

Jason Swanepoel, Vicky Yeung, and Meg Richey

EE 60 N | October 2, 2018

Agenda

A brief history

Key vocabulary

Plate tectonics overview

Calculating shifts

Formations due to plate tectonics

Advances in technology

Agenda

A brief history

Key vocabulary

Plate tectonics overview

Calculating shifts

Formations due to plate tectonics

Advances in technology

A brief history

Francis Bacon: parallelism of shores facing Atlantic

1620s

Alfred Wegener: existence of Pangaea and Continental Drift

1928

Arthur Holmes: thermal convection in mantle split two halves of Pangaea apart

Harry Hess: seafloor spreading theory

1912 1960s

Agenda

A brief history

Key vocabulary

Plate tectonics overview

Calculating shifts

Formations due to plate tectonics

Advances in technology

Key VocabularyLithosphere- the solid, outermost part of the mantle

Asthenosphere- below the lithosphere. Weak, partially melted

Subduction- One plate moving below another plate

Transform- Where two plates slide past each other

Seismicity- Frequency of earthquake activity

Agenda

A brief history

Key vocabulary

Plate tectonics overview

Calculating shifts

Formations due to plate tectonics

Advances in technology

Theory of plate tectonics: the lithosphere is broken into a dozen rigid plates that slide over partially molten, plastic asthenosphere

Types of Plate Boundaries

https://www.age-of-the-sage.org/tectonic_plates/volcanoes_earthquakes.gif

Examples of Divergent Plate Boundaries

http://image.wikifoundry.com/image/1/8YPnPXCDtCss1y16k_3INA150951/GW539H471 http://opentextbc.ca/geology/wp-content/uploads/sites/110/2015/07/image0492.png

https://i.stack.imgur.com/lA2PQm.jpg

Examples of Convergent Plate Boundaries

http://static.trunity.net/files/164101_164200/164130/subduction_types.jpg

Japan, Philippines, Indonesia, Mariana Islands, Aleutian Islands, Kuril Islands

Andes Mountains, Cascade Mountains

Himalayas, Atlas Mountains, Alps, Caucasus, Zagros Mountains, Tibetan Plateau

Examples of Transform Fault Plate Boundaries

http://4.bp.blogspot.com/-Cms59fd7PiY/VmRPJhFwBeI/AAAAAAAAHOY/QKJLwOybtIM/s1600/continental%2Btransform%2Bfaults.jpg https://geomaps.wr.usgs.gov/parks/pltec/SAtransform244x201.gif

Driving Mechanism?

http://www.tectonic-forces.org/images/fig02.jpg

Agenda

A brief history

Key vocabulary

Plate tectonics overview

Calculating shifts

Formations due to plate tectonics

Advances in technology

Calculating ShiftsCalculating the velocity of the shifts at various time allows for estimations of shifts overtime, allowing for better modeling of how Earth has changed and will continue to change.

http://web.ics.purdue.edu/~ecalais/teaching/eas450/plate_tectonics_2.pdf

Agenda

A brief history

Key vocabulary

Plate tectonics overview

Calculating shifts

Formations due to plate tectonics

Advances in technology

http://csmgeo.csm.jmu.edu/geollab/Fichter/PlateTect/Images/ophiohtm.gif http://csmgeo.csm.jmu.edu/geollab/Fichter/PlateTect/Images/ophiohtm.gif

Continental Shelf Deposits

http://www.sepmstrata.org/CMS_Images/coast_dep.jpg

Wilson Cycle

http://geography-student.blogspot.com/2012/02/wilson-cycle-opening-and-closing-of.html

Theory of Suspect TerranesThe idea that the continents are a patchwork of terranes each with its own unique geologic history.

Evidence:

1) Terrane contains rocks and fossils which differ from the rocks and fossils of neighboring terranes.

2) There are major faults at the boundary of each terrane.3) Magnetic properties of rocks differ between terranes.

https://image1.slideserve.com/2124821/suspect-terranes-n.jpg

Agenda

A brief history

Key vocabulary

Plate tectonics overview

Calculating shifts

Formations due to plate tectonics

Advances in technology

Advances in technology

● Magnetic anomaly bands are used to measure age of seafloor ● Isochrons allow reconstruction of the opening and closing of

oceans ● Fragmentation of Pangaea can be sketched

https://books.openedition.org/cdf/docannexe/image/2307/img-1.png

https://youtu.be/ewr0UhTvI7U

https://img.purch.com/w/660/aHR0cDovL3d3dy5saXZlc2NpZW5jZS5jb20vaW1hZ2VzL2kvMDAwLzA0Ny8zMzQvb3JpZ2luYWwvUGFuZ2FlYS5qcGc=

https://pics.me.me/one-tectonic-plate-bumps-into-another-and-says-sorry-my-6886362.png

https://memegenerator.net/img/instances/75433115.jpg

http://gykantler.com/wp-content/uploads/2011/08/Screen-shot-2011-08-23-at-2.53.30-PM.png