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Earth and Environmental Science 11–12 · Year 11

The continental jigsaw: fitting the continents at the edge of the shelf

Module 2: Plate Tectonics

PracticalLow risk

The idea

The continents fit at the continental shelf edge rather than the coastline, and matching rocks and fossils across the join are evidence that they were once one.

What you need

  • the Earthlearningidea continental jigsaw templates copied onto card, scissors
  • a bathymetric map of the South Atlantic from which the 500-fathom (about 900 m) depth contour on the continental slope can be traced
  • coloured pencils to mark fossil zones (Glossopteris, Mesosaurus, Lystrosaurus) and matching rock belts from a published map
  • Geoscience Australia tectonic plates jigsaw for the present-day plate mosaic

How to do it

  1. Assemble the Earthlearningidea jigsaw pieces into a supercontinent and compare the result with a neighbouring group.
  2. Cut out South America and Africa along the coastline and try to fit them; record the gaps and overlaps.
  3. Trace both continents along the 500-fathom contour, cut them out and fit them again; record the change.
  4. Colour the fossil and rock-belt zones and check whether they continue across the join.
  5. Assemble the plate jigsaw and mark the boundary types with three colours.
  6. Write the argument as evidence, inference and remaining doubt, and weigh it against the older land-bridge explanation the Earthlearningidea sheet asks pupils to consider.

What you should see

Bullard, Everett and Smith (1965) found by least squares that the Atlantic continents fit best at the 500-fathom contour on the steep continental slope, with root-mean-square misfits of 30 to 90 km for the pairs they fitted, so the slope outlines close gaps that the coastline fit leaves. Fossil zones and matching rock belts drawn from published maps continue across the join. The learner states why fit and fossils alone did not settle the question until sea-floor evidence supported plate movement.

What changes

This activity lists no variables to change, measure and keep the same.

Common misconceptions

Each of these ideas is wrong, and the activity is a chance to test it.

  • The continents fit at the coastline.
  • Wegener proposed plate tectonics (he proposed continental drift; the mechanisms he suggested were rejected, and plate tectonics came decades later).

Safety card

Low riskLearners carry it out

Hazards

  • scissors

Controls

No control is listed.

Note

No hazardous chemicals or heat sources: record the activity in the school's RiskAssess risk assessment, following the NSW Department of Education Science safety and compliance page; the Chemical Safety in Schools package is not triggered.

Curriculum references

The NSW syllabus outcomes and Australian Curriculum v9 codes this activity supports. They are references, not a verified or complete curriculum alignment.

  • Earth and Environmental Science Stage 6 Syllabus (2017), NESA; current, replaced by the 11–12 Syllabus (2025) from 2028EES11-9EES11/12-1EES11/12-2EES11/12-3EES11/12-4EES11/12-5
  • Earth and Environmental Science 11–12 Syllabus (2025), NESA; to be implemented from 2028, not yet taughtEES-11-01
  • Investigating Science Stage 6 Syllabus (2017), NESA; currentINS11-11
  • Australian Curriculum v9No Australian Curriculum v9 code is listed.

Sources

The pages the author read to write this activity.

  1. www.nsw.gov.au/education-and-training/nesa/curriculum/science/earth-and-environmental-science-stage-6-2017
  2. www.nsw.gov.au/education-and-training/nesa/curriculum/science/investigating-science-stage-6-2017
  3. www.earthlearningidea.com/PDF/85_Continental_jigsaw_puzzle.pdf
  4. www.ga.gov.au/education/classroom-resources/tectonic-plates-jigsaw-puzzle
  5. www.ga.gov.au/education/classroom-resources/plate-tectonics-teacher-notes-and-student-activities
  6. doi.org/10.1098/rsta.1965.0020

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