Sea Floor Spreading
The process where new oceanic crust forms along underwater mountain ranges and pushes older crust away.
What is Seafloor Spreading?
Sudden movements along tectonic plate boundaries cause this natural hazard.
What is an Earthquake?
This type of boundary occurs where two tectonic plates slide horizontally past one another.
What is a Transform Boundary?
This layer is the thin, outermost solid layer of the Earth that we live on.
What is the Crust?
The German scientist who proposed the hypothesis of Continental Drift in 1912.
Who was Alfred Wegener?
Long underwater mountain ranges where seafloor spreading occurs.
What are Mid-Ocean Ridges?
Molten rock that breaks through Earth’s surface is called lava, but while it is still beneath the surface, it is called this.
What is Magma?
The boundary type where two plates pull apart or move away from each other.
What is a Divergent Boundary?
Made mostly of liquid iron and nickel, this layer creates Earth’s magnetic field.
What is the Outer Core?
The name of the giant supercontinent that existed over 200 million years ago before breaking apart.
What is Pangea?
Compared to rock found far from a mid-ocean ridge, rock found directly at the ridge is this
What is younger (or newer)?
The theory that combines Continental Drift and Seafloor Spreading into one unified model explaining Earth’s moving outer shell.
What is the Theory of Plate Tectonics?
When two continental plates collide at a convergent boundary, this primary landform feature is produced.
What are Mountain Ranges (e.g., the Himalayas)?
This layer is solid because it is under so much pressure.
What is the Inner Core?
Fossils of the ancient, heavy-seeded fern Glossopteris were found across South America, Africa, Antarctica, India, and Australia. Explain why its seeds served as strong evidence for Pangea rather than spreading by wind or water.
What is because the seeds were too large/heavy to be blown by wind and could not float across saltwater ocean basins?
Deep underwater valleys where old oceanic crust sinks back into the mantle through subduction.
What are Ocean Trenches?
The Ring of Fire, a region around the Pacific Ocean known for frequent earthquakes and volcanoes, is mostly formed by this type of plate boundary.
What are Convergent Boundaries?
The process where a denser oceanic plate sinks beneath a lighter continental plate back into the mantle.
What is Subduction?
This heat-driven process in the mantle occurs when hot material rises and cooler material sinks, driving the movement of tectonic plates.
What are Convection Currents?
Besides fossils, name two other pieces of evidence Alfred Wegener used to support Continental Drift.
What are continental fit (puzzle-piece fit), matching mountain ranges/rock strata, or glacial evidence?
Scientists used radiometric age dating on core samples taken from the ocean floor to discover that the oldest oceanic crust is only about 200 million years old, whereas continental rocks can be over 4 billion years old. Explain why oceanic crust is so much younger.
What is because oceanic crust is continuously recycled back into the mantle through subduction, while lighter continental crust resists subduction?
Why oceanic crust subducts under continental crust during a collision.
What is because oceanic crust is denser (and thinner) than continental crust?
Name the specific boundary type and geological event associated with the San Andreas Fault in California.
What is a Transform Boundary?
This layer of Earth is affected by convection currents and causes this layer of oceanic and continental crust to move.
What is the crust?
Scientists initially rejected Wegener’s hypothesis for this specific reason.
What is because he could not explain the force/mechanism that moved the continents?