Study guide: Earth Plates and the Rock Cycle
Model plate boundaries and rock transformations.
Ideas to explain in your own words
- Tectonic plates are moving pieces of lithosphere. Divergent boundaries separate, convergent boundaries approach and transform boundaries slide past. Actual boundaries have varied geometry and behavior.
- Rocks transform through melting, cooling, weathering, burial, heat and pressure. There is no single required loop; many possible pathways occur on different timescales.
- Displacement in centimeters equals centimeters per year multiplied by years. Long extrapolations require the constant-rate assumption.
- Scientists combine fossil patterns, rock matches, earthquake distributions and seafloor patterns. One clue alone can have limits. Our descriptions identify what each evidence line measures.
Useful vocabulary
- divergent
- plates move apart
- melting
- solid rock becomes molten material
- cm
- Centimeter is one hundredth of a meter.
- Displacement in centimeters
- Displacement in centimeters equals centimeters per year multiplied by years.
- fossil pattern
- matching ancient organism evidence
Watch your reasoning
- Confusing divergent with convergent although their functions or changes differ.
- Confusing melting with cooling although their functions or changes differ.
- Using the distractor operation a/b instead of a*b; Multiply a rate by time.
A worked review example
Worked supplied problem: Ocean-floor ages increase away from a ridge on both sides. Explain a mechanism fitting the pattern. Solution: New crust forms near the spreading region while plates move apart. Older crust is carried farther away over time. The pattern supports spreading when combined with other evidence. This conclusion uses the stated observations and the mechanism explained above; it does not establish every unmeasured feature of a real organism, device or place. Worked supplied problem: One buried rock stays solid but changes under heat and pressure; another melts then cools. Compare their pathways. Solution: The first undergoes metamorphism without complete melting. The second can form igneous rock on cooling. Calling both sedimentary ignores the distinct supplied processes. This conclusion uses the stated observations and the mechanism explained above; it does not establish every unmeasured feature of a real organism, device or place. Worked distinct example: A distinct model moves 4 cm/year for 8 years: 4×8=32 cm. Method: identify the quantities in the stated rule, substitute using compatible units, and perform the operations in the correct order. Multiply a rate by time. These model rates are not measurements of a named plate. Interpret the final unit and keep the model assumption visible; this calculation is not a measurement of a real learner or site. Worked supplied problem: Matching coastal rocks and land fossils occur on separated continents. Explain why these clues should be combined. Solution: The different records jointly support a former connection or shared geological history. Each has identification and preservation limits; combining independent evidence is stronger than inferring a complete history from one resemblance. This conclusion uses the stated observations and the mechanism explained above; it does not establish every unmeasured feature of a real organism, device or place.
Make a practice plan
- Explain the mechanism in Describe plate boundaries using a labeled case.
- Complete Connect rock-cycle transformations and correct the specific misconception in its feedback.
- Resolve a changed case from Model plate displacement, then combine the four ideas in the transfer task.