CHAPTER 6 LESSON 1-4

By: Kaylynn PridaySam Davis

VOCABULARY LESSON 1

Uniformitarianism- is a principle that states that the same geologic processes shaping the Earth today.

Catastrphism- is a principle that states all geologic change occurs suddenly.

VOCABULARY LESSON 2

Relative Dating- determining weather an object or event is older or younger than other objects or events.

Superposition- is a principle that states that younger rocks lie above older rocks in undisturbed sequences.

Geologic column- is an ideal sequence of rock layers that contains all the known rock and fossil formations on Earth arranged oldest to youngest.

Unconformity- a surface that represents a missing part of the geologic column.

VOCABULARY LESSON 3

Absolute dating- is the process of establishing the age of an object, such as a fossil or rock layer, by determining the number of years it has existed.

Isotopes- are atoms of the same element that have the same number of protons but have different number of neutrons.

Radioactive Decay- radioactive isotopes breaking down into stable isotopes of other elements.

Radiometric Dating- determining the absolute age of a sample based on the ratio of parent material.

Hafe-life- the time it takes for one-hafe radioactive sample to decay.

 

VOCABULARY LESSON 4

Fossil- any naturally preserved evidence of life.Permineralization- a process in which fill in pore

spaces of an organism’s tissues.Petrification- occurs when the organism’s tissues are

completely replaced by minerals.Trace Fossil- any naturally preserved evidence of an

animals activity.Coprolites- are preserved feces of animals.Mold- is a cavity in the ground or rock where a plant or

animal was buried.Cast- is an object where sediment fills in a mold and

becomes a rock.Index Fossils- fossils of an organism that lived during a

relatively short, well-defined time span.

UNIFORMITARIANISM

What's the difference?Uniformitarianism is a principle that states that

the same geologic process shaping the Earth today have been at work throughout Earth’s history. Catastrophism is a principle that states that all geologic change occurs suddenly.

 Scientists had thought the Earth formed by

catastrophism

RELATIVE DATING

Determining weather an object or event is older or younger than other objects or events.

 The Geologic ColumnIs an ideal sequence of rock layers that

contains all the known fossils and rock formations on Earth arranged from oldest to youngest. When geologists are not sure about the age of a rock sequence they are currently studing, they gather information about the sequence and compare it to the geologic column.

 

Disturebed Rock LayersFaultIs a break in the Earth’s crust along which blocks of the

crust slide relative to one another.

IntrusionIs molten rock from the Earth’s interior that squeezes

into exsiting rock and cools.

FoldingOccurs when rock layers bend and buckle from Earth’s

internal forces.TiltingOccurs when internal forces in the Earth slant rock

layers without folding them. 

Unconformities

Disconformity- exists where part of a sequence of a parallel rock layers is missing.

Nonconformity- exists where sedimentary rock layers lie on top of an eroded surface of nonlayered igneous or metamorphic rock.

Angular Unconformity- exists between horizonal rock layers and rock layers that are tilted or folded