Abstract

Plate tectonics forms a fundamental component of our understanding of how Earth works. In this activity, students examine the age of the ocean crust, calculate the rate of seafloor spreading at different locations around the world, and compare the spreading rates within the context of plate tectonics. They do this using GeoMapApp - the free geoscience map-based software developed at Lamont.

Spreading rates are calculated for three different ocean basins: South Atlantic across the Mid-Atlantic Ridge, Pacific across the East Pacific Rise, and the area between Australia/Antarctica across the Southeast Indian Ridge. Each area has quite different spreading characteristics.

In addition, the ability within GeoMapApp to layer multiple data sets and use a transparency slider to compare layers allows the activity to be expanded to investigate, for example, depth-age relationships of the cooling lithosphere, or global heat flow, or the global geoid anomaly.

Context

When teaching the basics of plate tectonics, too often students are simply told the rate of seafloor spreading in different basins. This activity allows students to generate the numbers themselves and can be done on an individual basis, as pairs, or as groups.

Why It Works

(1) It provides a valuable opportunity for students to get their hands on authentic research-grade geoscience data using the same cutting-edge technological tool used by researchers. (2) Each student generates their own set of profiles which fosters an increased sense of data "ownership". (3) The use of basic Pythagorean triangle gradient calculations further promotes STEM skills. (4) The different spreading rates should present a great opportunity for students to discuss the differences in what they found.

Link

https://serc.carleton.edu/geomapapp/activities/seafloor_spreading.html