Units 2 & 3 Earth Sem 1 Formation and Plate Tectonics

What caused the early Earth to become a molten sphere?

• The gravitational pull of the Sun

• The accumulation of gases from space

• Intense heat from collisions and radioactive decay

• The formation of the oceans

Which process led to the layering of Earth's interior?

• Erosion

• Differentiation by density

• Oceanic sedimentation

• Solar wind pressure

The inner core is composed mainly of:

• Silicates and water

• Solid iron and nickel

• Liquid rock

• Radioactive uranium

What is the primary source of heat driving mantle convection?

• Solar radiation

• Chemical reactions in the crust

• Radioactive decay of isotopes

• Gravitational attraction of the Moon

The lithosphere consists of:

• The inner core and outer core

• The crust and uppermost mantle

• The mantle and outer core

• The entire solid portion of the Earth

Seismic waves help scientists understand Earth’s interior by:

• Allowing direct measurement of the mantle

• Moving only through the oceanic crust

• Changing speed and direction through different materials

• Producing earthquakes at plate boundaries

Which type of seismic wave cannot travel through liquids?

• P-waves

• S-waves

• Surface waves

• Shock waves

The geochemical cycle describes:

• The transfer of elements through Earth’s systems

• The process of mountain formation

• The movement of tectonic plates

• The cooling of the inner core

What is the asthenosphere?

• The rigid outer shell of Earth

• The solid core at the planet’s center

• A partially molten layer beneath the lithosphere

• The source of Earth’s magnetic field

Which process creates new oceanic crust at mid-ocean ridges?

• Plate subduction

• Seafloor spreading

• Tectonic uplift

• Sedimentation