Rock Types
This kind of rock forms from pieces of pre-existing rocks or remains of once-living things that are compacted and cemented together
What is Sedimentary rock
The type of age that tells whether a rock is older or younger than nearby rocks (not its age in years).
What is Relative age.
The method of matching the same rock layers or fossils across different places to make a longer sequence is called what?
What is Geologic correlation.
What do we call a gap in the rock record where some layers are missing because of erosion or no deposition?
What is an unconformity
Name one rock that forms from cooled lava at Earth’s surface.
What is Basalt (also acceptable: obsidian, scoria, pumice).
Figuring out which rocks, fossils, and geologic events are older or younger compared to others, without knowing their exact age in years is called __________ ___________
What is relative dating
The word for rock layers viewed from the side, showing layers above and below ground, is what?
What is geologic profile
A fault (crack) is younger or older than any rock layers it breaks
What is younger
This rock is a metamorphic rock that originally was limestone before heat and pressure changed it.
What is Marble
When a molten rock cools and solidifies underground it forms this type of rock. Use the term (igneous, metamorphic, or sedimentary).
What is Igneous rock.
A simple name for rock layers is “rock ______.”
What is Strata
This type of rock, if present, is older than any non-metamorphic rock it touches
What is Metamorphic rock
Give two examples of sedimentary rocks made from once-living organisms.
What are Coal and limestone (also acceptable: coquina).
Describe what is meant by a “rock sequence.”
What is A rock sequence is rock strata arranged in time order from oldest (bottom) to youngest (top).
What is a geologic profile?
What is a side‑view diagram that maps the positions of rock strata above and below the ground.
This type of rock is younger than any rock it melts into or cools on top of.
What is Igneous rock
Explain how granite and basalt differ in where they form (use relative location: underground vs. at the surface).
What is Granite forms when magma cools slowly underground; basalt forms when lava cools quickly at the surface
Explain why a metamorphic rock is not considered a new rock formed from melting and cooling like igneous rock; include what changes happen to the original rock.
What is Metamorphic rocks form when a pre-existing rock is changed physically and chemically by added heat and pressure (recrystallization and texture/mineral changes) without melting into magma; unlike igneous rocks, they are not formed by melting and cooling.
Describe what happens to rock layers when they are tilted and then new younger layers are deposited on top. Which relative-age principle explains the order?
What is The tilted (older) layers were deposited first, then were tilted by forces, and later newer, flatter layers were deposited on top.
Name one reason an unconformity might form (give one of the two main reasons).
What is either erosion removed rock layers OR the environment changed so no new rock was deposited for a long time.