Seafloor Spreading

The rocks from either side of the Mid-Atlantic ridge provide evidence to support the theory of plate tectonics, because when we look at rocks farther from the ridge, the rocks.....

• have higher iron content.

• are made up of smaller particles.

• become thicker and thicker.

• are consistently older.

Scientists study rock strata and shapes of continents to understand the movement of _______________.

New seafloor material is formed at places in Earth's crust where...

• Rock is broken into pieces as tectonic plates push against one another.

• One tectonic plate slides beneath another and is forced downward.

• Lava flow from volcanic eruptions builds up over many thousand of years.

• Magma rises into the spaces where tectonic plates pull away from one another.

When 2 tectonic plates pull apart, a __________ is formed on the ocean floor.

Continental shelves fitting together is evidence that...

• the continental shelves are made up of the same rock material

• the tectonic plates of both are roughly the same age

• the continents were joined in the past

• the material that makes them up comes from sediments eroded from the continents.

The process in which a denser plate is pushed beneath a less dense plate.

• Trenches

• Divergent Boundary

• Lithosphere

• Subduction

• Tectonic Plates

The rigid, outermost layer of Earth

• Trenches

• Divergent Boundary

• Lithosphere

• Subduction

• Tectonic Plates

Massive pieces of land that are part of Earth's crust and upper mantle

• Trenches

• Divergent Boundary

• Lithosphere

• Subduction

• Tectonic Plates

Old seafloor is destroyed at __________.

Part of the cycle of recycling seafloor material includes it getting destroyed. This occurs...

• through weathering and erosion of exposed rock layers.

• as a result of violent and constant volcanic activity.

• at trenches where rock material is subducted.

• when elements in rock are rearranged chemically.