Rocks and Fossils
This shows which organisms were alive and how earth's environment has changed.
What can rock fossils show about earth's past?
We can determine this by studying rock layers.
What is relative age?
This is the theory that the earth once consisted of a large land mass where all seven continents were united.
What is Pangea?
This is a cycle that illustrates that one type of rock can change into another type of rock.
What is the rock cycle?
This type of current has heat rising to the crust and cold falling to the core.
This happens because hot molten rock destroys plants and animals, but sedimentary rock preserves remains.
Why do rock fossils form in sedimentary, not igneous rock?
This type of rock is used to determine the relative age of events and objects in earth's history.
What is sedimentary rock?
A chart that helps us understand earth's history, and is defined by major events or changes.
What is the geologic time scale?
This type of rock can change into another type of rock through the process of heat and pressure.
What is a metamorphic rock?
This is the amount of time it takes half of the atoms in a sample to decay.
What is half-life?
These are the number of rings around a tree trunk, which tell us the relative age of the tree.
What is a tree ring?
This layer of rock is found on the top, not the bottom.
What is the youngest layer of rock?
During this era, the dinosaurs reigned on earth.
What is the Mesozoic era?
This type of fault forms when two faults slip past each other in opposite directions.
What is transform faults?
The process by which an unstable atomic nucleus loses energy by radiation.
What is radioactive decay?
These are traces or remains of living things from long ago.
What is a fossil?
This type of rock forms when hot molten lava penetrates other layers and cools.
What is igneous rock?
This object from space decimated the earth and caused dinosaurs to die.
What is a meteorite?
This mineral is found in the center of the earth, forms magma, and is very hot.
What is iron?
These are the 4 major time periods within the geologic time scale?
What are the Precambrian era, Paleozoic era, Mesozoic era, and the Cenozoic era?
Ice, Amber, and Tar.
What are different types of fossil preservatives?
These fossils are from organisms that were common, lived in many areas and existed only during specific spans of time.
What are index fossils?
When looking at rock layers, this layer is where the oldest rocks are found.
What is the bottom layer?
This age is the exact age of an organism.
What is absolute age?
This geologic change occurred during the Mesozoic era.
What is pangaea?