Geologic Time
What percentage of Earth’s history occurred in the Precambrian?
88%
Igneous rocks form when what cools?
Magma or lava
What boundary creates earthquakes from sliding plates?
Transform
Fastest seismic wave?
P-wave
Which sphere includes all living things?
Biosphere
Dinosaurs appear in what era?
Mesozoic
Sedimentary rocks form by what two processes?
Cementation & compaction
What boundary creates mountains?
Convergent (continental–continental)
Most damaging seismic wave?
Surface wave
Which sphere includes all water?
Hydrosphere
Why are Precambrian fossils rare?
Organisms were soft-bodied and microscopic.
Metamorphic rocks form from what?
Heat and pressure
Oceanic plates are made of what rock type?
Basalt
The location underground where an earthquake begins is called the…
Focus
Which sphere includes gases around Earth?
Atmosphere
What does the suffix “–zoic” mean?
Zoo / life
What does “organic” mean?
Comes from a living thing
Continental plates are (thick/lighter OR thin/dense)?
Thick and lighter
The point on Earth's surface directly above the focus is the…
Epicenter
Which sphere includes all rocks and minerals?
Geosphere
Which period saw the “Big Bloom” of flowering plants?
Cretaceous
What is a cast fossil?
A filled-in copy of an organism
What drives plate movement in the mantle?
Convection currents
Which instrument records seismic waves?
Seismograph
Weather occurs in which layer of the atmosphere?
Troposphere
What event ends each major era?
Mass extinction
What property does a streak test show?
The mineral’s powder color
Lava at divergent boundaries forms what feature under oceans?
Mid-ocean ridges
Which volcano type forms from thin, runny lava?
Shield volcano
Solar energy from the Sun primarily drives what Earth process?
Weather/climate
Which eon contains most visible life?
Phanerozoic
Deeper fossils are (older/younger)?
Older
What happens when oceanic crust meets continental crust?
Subduction → volcanoes
Which layer of Earth is solid metal?
Outer core
Geothermal energy comes from where?
Earth’s internal heat
Humans evolved during which era?
Cenozoic
What kind of fossils help match rock layers across regions?
Index fossils
Describe the three plate boundaries.
Convergent = collide
Divergent = separate
Transform = slide past
Which volcano type forms from thick, explosive lava?
Composite volcano
Renewable energy means what?
Energy with an unlimited supply (solar, wind, geothermal).
What major geologic event formed at the end of the Paleozoic?
Pangaea formed
What is foliation?
Layered/banded texture in metamorphic rocks
Which layer do convection currents occur in?
Mantle
What type of plate boundary creates volcanoes?
Convergent (ocean–continental)
Give one example of two spheres interacting.
Rain (hydrosphere) grows plants (biosphere).
What is the present-day eon, era, period, and epoch?
Phanerozoic → Cenozoic → Quaternary → Holocene
What makes mafic igneous rocks unique?
They are dark and dense.
What is subduction?
Oceanic plate sinks under continental plate
What are the 4 layers of the Earth
Crust
Mantle
Outer Core
Inner Core
What does the 2nd Law of Thermodynamics say?
Energy cannot be destroyed or created only transform