Unit 2 Earth's History

which example is NOT a way organisms become preserved as fossils

What is radioactive decay

What processes can cause rock to break apart into sediment

What are index fossils used for

Parent Isotope = 16 Daughter Isotope = 0 100% of the sample is parent isotope. What will it be after 2 half-lives

What are ripple marks on a rock

The idea that the same geologic processes that shape earth today have occurred throughout earth's history

which is not an example of a trace fossil

geological processes happen at a slow rate

There are no Earth rocks which can be directly studied that are as old as our planet

the law of crosscutting relationships states that a fault or a body of rock, such as an intrusion must be

all of the fossils that have been discovered on earth are called the

a geologic column is

the time needed for half of a sample to undergo radioactive decay to form daughter isotopes

This method is used to date rocks that are between about 100,000 years and a few billion years old

we can find out past climates from all of them but ONE

the law of superposition states that

what is Pangaea

fossils can tell us how life forms have changed over time

petrification happens

a fossilized structure that formed in sedimentary rock by animal activity on or in soft sediment is a

fossils can tell scientists about environmental changes over time

The principle that states all geologic changes occurs suddenly

what do scientists use tree rings for

determining whether an object or event is older or younger than other objects or events is called

the ages of wood, bones, shells, and other organic remains can be found by

This method is used to determine the age of igneous rocks that are between 100 million years and billion years old

mud cracks show that an ancient lake, stream, or ocean shoreline was once a part of an area

What is absolute Dating

what states that geologic processes that happened in the past can be explained by current geologic processes

What are fossils

which is NOT a way sedimentary rock layers get disturbed

The average rate of geologic change is fast

how old is earth approximately

Make sure you are studying the defining events of each Era

what is amber

inconformity is

what are the trace or remains of an organism that lives long ago, most commonly preserved in sedimentary rock

Geology is the scientific study of origin, history, and structure of Earth and processes that shape it.

The largest unit of geologic time is an