Pangaea Clues Review Worksheet
Earth Science Review Grade 8 • Plate Tectonics & Drift
Pangaea Clues Review Worksheet
Investigating Continental Drift, Rock Evidence, and Modern Tectonic Theory
Name:
Date: Period:
Part 1: Wegener’s Four Lines of Evidence (Matching & Analysis)
4 Points
Match each piece of observational evidence to its geological clue category. Then, complete question 5.
Observed Evidence
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Identical Glossopteris seed-fern fossils found across Africa, India, and Antarctica.
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Appalachian Mountain rock structures in North America align directly with Scottish Highlands.
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Matching sequences of sedimentary rock layers (strata) in Brazil and South Africa.
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Glacial striations (bedrock grooves) and tillite deposits found in modern tropical India & Africa.
Category Bank
A. Stratigraphy & Lithology (Rock Type & Age)
B. Fossil Correlation Across Marine Barriers
C. Mountain Belt & Structural Continuity
D. Paleoclimate & Glacial Bedrock Evidence
Write matching letter (A–D) in the corresponding box.
5. Climatological Reasoning: Explain why the presence of ancient glacial bedrock striations in equatorial India and Africa supports continental drift rather than global cooling.
Part 2: Hypothesis to Theory — Resolving the Missing Mechanism
6 Points
| Key Dimension | Wegener's Continental Drift (1912) | Modern Plate Tectonics (1960s) |
|---|
| Proposed Movement | Continents plowed directly through stationary ocean floor crust. | Lithospheric plates (crust + upper mantle) ride on the asthenosphere. |
| Driving Mechanism | Speculated lunar tidal forces & Earth rotation (rejected by peers). | Mantle convection currents, seafloor spreading & subduction slab pull. |
| Ocean Floor Rocks | None available (ocean floors assumed to be featureless and ancient). | Basalt age gradient (youngest at ridges, older outward), magnetic reversals. |
6. Harry Hess & Seafloor Spreading: Describe the age gradient of seafloor basalt rocks as distance increases from a mid-ocean ridge.
7. Misconception Alert: Explain why tectonic plates do not float on "liquid magma" using the term solid, plastic asthenosphere.
Unit: Earth Dynamics & Geological Clues Page 1 of 2 • Continue to Page 2
Plate Boundaries, Rock Formations, & Scientific Argumentation
Pangaea Clues Review Worksheet • Page 2
Student Name:
Part 3: Plate Boundary Interactions & Rock Formations
5 Points
Review the boundary interactions below and answer question 8.
| Boundary Type | Motion | Features & Rock Formations | Real-World Example |
|---|
| Divergent | \( \leftarrow \quad \rightarrow \) | Magma rises & cools into new igneous basalt crust; mid-ocean ridges & rifts. | Mid-Atlantic Ridge, Iceland |
| Convergent (Ocean–Continent) | \( \rightarrow \quad \leftarrow \) (subduction) | Dense oceanic crust subducts; forms deep trenches & volcanic mountain arcs. | Cascade & Andes Mountains |
| Convergent (Continent–Continent) | \( \rightarrow \quad \leftarrow \) (collision) | Crust crumples without subduction; builds massive folded mountain ranges. | Himalayan Mountains |
| Transform | \( \uparrow \quad \downarrow \) (sliding) | Plates grind horizontally; creates fault zones and frequent severe earthquakes. | San Andreas Fault |
Rock Identification: At which plate boundary type is the youngest igneous rock actively created, and at which boundary are sedimentary rock layers folded into high mountain ranges?
Part 4: CER Scientific Argumentation Task
5 Points
Prompt: In 1915, Alfred Wegener presented extensive rock and fossil evidence, yet scientists rejected his hypothesis. Construct a scientific explanation explaining why his hypothesis was rejected and how mid-century ocean floor discoveries validated his core idea.
CLAIM (Answer the prompt directly in one clear sentence):
EVIDENCE (Cite at least 1 rock/fossil clue from Wegener AND 1 ocean floor discovery from Hess/sonar mapping):
REASONING (Explain using scientific principles: asthenospheric convection currents & seafloor spreading mechanism):
NGSS MS-ESS2-1 • MS-ESS2-2 • MS-ESS2-3 Total Score: _______ / 20
