The Rock Cycle
Which type of rock forms when lava or magma cools and hardens?
What is igneous rock?
What is a fossil?
Preserved remains or traces of ancient organisms.
What principle states that the oldest rock layers are on the bottom?
Law of Superposition.
What theory explains the movement of Earth’s plates?
Plate Tectonics.
What do we call lava that cools and hardens on Earth’s surface?
An extrusion.
What two processes turn loose sediments into sedimentary rock?
What are compaction and cementation?
Which rock type typically holds fossils, and why?
Sedimentary rock, because it forms in layers that gently trap and bury organisms.
What is relative dating used for?
Determining the age order of rock layers, not exact years.
What happens at a divergent boundary?
Two plates move apart, forming new crust.
What do we call magma that cools and hardens beneath Earth’s surface?
An intrusion.
Why are sedimentary rocks more likely to contain fossils than other rock types?
Because of low heat and pressure
What is the best type of preservation method?
Ice
How can an intrusion help scientists determine relative age?
An intrusion is younger than the rocks it cuts through.
What happens at a convergent boundary?
Two plates collide, Destroying crust
How can plants contribute to both weathering and erosion?
Roots break rocks apart (weathering), and once loosened, wind/water move sediments (erosion).
Describe how a metamorphic rock could eventually become igneous.
It must melt into magma and then cool/harden.
What's the difference between replacement Petrification, and Permineralization Petrification?
Replacement replaces all organic material, while Permineralization preserves organic material
What is an unconformity?
A gap in the rock record showing erosion or missing layers.
How does mantle convection drive plate movement?
Hot material rises and cool material sinks, creating slow-moving convection currents.
Explain how glacial movement transforms the landscape.
Glaciers scrape and grind rock surfaces, carrying debris that reshapes valleys and plains.
Explain how all three rock types are connected and can transform into one another
Igneous and Metamorphic to sedimentary through Weathering, erosion, and Deposition
Igneous and Sedimentary to Metamorphic through heat, and pressure,
Sedimentary and Metamorphic to Igneous through melting, and cooling
Compare fossilization in tar pits and in amber.
Tar traps and seals large organisms; amber preserves small organisms like insects.
If a fossil is found in two different rock layers on separate continents, what conclusion can be made?
Those layers formed during the same time period because they contain the same index fossil.
Who were the two scientists who established theory of continental drift and sea floor spreading that lead to the modern understanding of plate tectonics?
Harry Hess & Alfred Wegner
Describe how uplift and erosion could expose ancient rock layers at Earth’s surface.
Tectonic forces push old rocks upward, and weathering/erosion remove overlying layers.