Sediment Deposition Supports Seafloor Spreading

Jerry Cook, Tavia Prouhet, and Ramona Smith
Type Category
Instructional Materials
Lesson/Lesson Plan , Data , Graph
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be “fully aligned,” the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.



In this activity, students manipulate and graph data collected by the research vessel, JOIDES Resolution, to determine whether sediment thickness located near the Juan de Fuca Ridge supports the concept of seafloor spreading.  Teachers can choose between two formats: a Google Earth based version or a pen and paper one.  In the former version, students will be tasked with finding and recording the pertinent data before calculating sediment and basalt depths.  In the latter, students are provided with data but must still do all depth calculations.  In both formats, students will manually draw their graphs.  The Teacher Guide provides an answer key for the calculations, graph and short answer questions. The authors state that the activity can be completed in one class period; however, given the amount of calculations and graphing, this is an optimistic estimate at the middle school level.

Intended Audience

Educational Level
  • Grade 8
  • Grade 7
  • Grade 6
  • Middle School
Access Restrictions

Free access - The right to view and/or download material without financial, registration, or excessive advertising barriers.

Performance Expectations

MS-ESS2-3 Analyze and interpret data on the distribution of fossils and rocks, contintental 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.

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
Sediment Deposition Supports Seafloor Spreading specifically deals with sediments and seafloor structures to provide evidence of plate movement. In order to fully achieve the Performance Expectation, teachers will need to incorporate lessons dealing with fossil distribution and continental shapes. One such lesson is Continental Drift Activity, a vetted resource in the NGSS Hub which deals with rock and fossil distributions.

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
Students use sediment core and sonar data collected by the JOIDES Resolution to calculate both ocean floor and basalt depths. Students then graph their results as a function of distance from the Juan de Fuca Ridge located off the Pacific Northwest coast of North America. The area between their two lines (ocean floor and basalt depths) represents the sediment thickness. Since sedimentation rates are fairly constant, students should deduce that thicker sediments will be found on older basalt and that this basalt is found farther from the ridge. Thus, students will be able to conclude that sediment thickness is an indicator of seafloor spreading. The calculations that are required prior to generating the graph may prove difficult for some students; teachers may want to simplify the graphing process by providing the ocean sediment thickness so that students will only need to graph a single line. In addition, teachers may wish to rework the scale of the provided graph to make it easier for students to use. Once the graph has been completed, students can answer the questions provided in the activity as a means of analyzing the relationship between the two variables.

Disciplinary Core Ideas

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
In this activity, students determine that a relationship exists between the thickness of the sediment layer and its distance from the ridge: thicker sediments are located farther from the ridge while thinner layers are closer. Using this information, students conclude that new seafloor is forming and moving away from the ridge. Since this activity only deals with sediments and not fossils, teachers will need to incorporate other activities specifically dealing with fossils in order to complete the Disciplinary Core Idea. Teachers may consider using Nannofossils Reveal Seafloor Spreading Truth or Activity: A Plate Tectonic Puzzle, two vetted resources found in the NGSS Hub, to address this deficit. The Nannofossils Activity deals with real world data while the Plate Tectonic Puzzle is a traditional Pangaea hands on activity.

Crosscutting Concepts

This resource appears to be designed to build towards this crosscutting concept, though the resource developer has not explicitly stated so.

Comments about Including the Crosscutting Concept
The Crosscutting Concept of Patterns is utilized when students evaluate the relationship between the thickness of the sediment layer and its distance from the ridge as displayed in their completed graphs. Students may notice that there is not a perfect linear relationship between the two variables; some variation exists across the entire graph. In order to aid students in the analysis of their finished work, teachers may want to initiate a two part discussion. The first part of the classroom discussion would focus student attention on general patterns when analyzing the spatial relationship in their graphs. The second part would center on the variability of data in any real world scenario. Once students have a general understanding of their data, they should be equipped to answer the analysis questions.

Resource Quality

  • Alignment to the Dimensions of the NGSS: Sediment Deposition Supports Seafloor Spreading is aligned to all three dimensions of NGSS. In this lesson, students utilize the Practice of Analyzing Data by using real world measurements from the Deep Sea Drilling Project in order to build an argument for seafloor spreading. Student analysis relies on the Crosscutting Concept of Patterns since the use of this concept is necessary in order to identify the relationship between sediment depth and distance from the ridge. Correct analysis of this relationship leads to understanding the Disciplinary Core Idea that land patterns, based on sediment analysis, can provide evidence of plate movement. Students will conclude that the thicker sediment layers are farther from the axis of the Juan de Fuca Ridge while thinner layers are closer. This conclusion supports the concept that, over the course of millions of years, tectonic plates have moved.

  • Instructional Supports: In this activity, students engage in an authentic scenario using data obtained from the Deep Sea Drilling Project. The lesson uses grade appropriate, scientifically accurate information and includes ways for students to present their ideas through the graphs they create. The lesson does not provide any guidance for differentiation; in fact, teachers may need to design supports for students with limited math abilities. Finally, it would be difficult for most students to connect this activity to their own life experiences.

  • Monitoring Student Progress: Teachers will be able to monitor 3D student performance since students must identify patterns when analyzing the data in their constructed graphs in order to obtain evidence for seafloor spreading. Since the lesson does not specifically reference patterns, teachers may need to assist students by directing their attention to the patterns observed in the graphs. The lesson, however, lacks teacher support since it does not provide embedded formative assessments, scoring guidelines or rubrics.

  • Quality of Technological Interactivity: Although teachers may opt to use the Google Earth format for this activity, Sediment Deposition Supports Seafloor Spreading does not have any true interactivity.