MS - ESS1 Seafloor Spreading - FINAL (WND 12-12-13)

Module: Seafloor Spreading

DCI: ESS1.C (A2) Tectonic processes continually generate new ocean sea floor at ridges and destroy old sea floor at trenches.

PE: MS-ESS2-3 Analyze and interpret data on the distribution of fossils and rocks, continental shapes, and seafloor structures to provide evidence of the past plate motions.

[Clarification Statement: Examples of data include similarities of rock and fossil types on different continents, the shapes of the continents (including continental shelves), and the locations of ocean structures (such as ridges, fracture zones, and trenches).]  [Assessment Boundary: Paleomagnetic anomalies in oceanic and continental crust are not assessed.]

In order to ask questions from the DCI - it is ok to ask basic questions about where new crust is created and old crust is destroyed.  It might be helpful to do this with a diagram.  For the PE, we will have to provide data (fossil evidence, Pangaea, landforms, etc) and use them to support the idea that the plates have moved away from each other in the past. 

In general, we we talk about three types of tectonic plate movement (pushing together, pulling apart, sliding past), it will be important not to lock ourselves into questions which only have three logical answers.  For this standard, we will not be looking at the type of landforms that form as a result of movement UNLESS they are directly related to the formation of new crust or the recycling of old crust OR they provide evidence for past plate motions.  We should not be asking things like "The movement of tectonic plates towards each other is responsible for the formation of which of the following land features?"

It is not acceptable to ask about specific places on the Earth's crust unless we provide some background information. (For example, it would not be okay to ask "Which of the following provides evidence for the idea that tectonic plates are moving apart from one another? correct answer = The Mid-Atlantic Ridge, wrong answers - the Grand Canyon, Chixulub Crater, Ayers Rock").  This will have to be done in a more general manner if it is to be included. 

Although, it is acceptable for students to be asked to recognize types of features (ridges, fracture zones, and trenches) as evidence for plate movement. 

Possible Question Starters: 

"New tectonic plate material is formed at places in the Earth's crust where - "

correct answer - molten rock material can rise into spaces created when tectonic plates are moving apart

wrong answer - solid crust breaks apart into pieces where tectonic plates are moving in opposite directions

"The idea that tectonic plates have moved away from each other in the past can be supported by which of the following types of evidence?"

correct answer - fossil remains of similar plants and animals found on different continents

wrong answer - changing composition of rock layers found at different depths