Relative Dating

Question 1

What are the two classifications of Geologic Dating?

Answer 1

Absolute and Relative Dating

Question 2

It means placing rocks in their proper sequence of formation, first, second, third, and so on.

____________ ____________ cannot tell us how long ago something took place, only that it followed one event and preceded another.

Answer 2

Relative Dating

Question 3

What are the six key principles of relative dating?

Answer 3

Law of Superposition, Law of Original Horizontality, Law of Lateral Continuity, Law of Cross-Cutting Relationships, Law of Inclusions, Principle of Fossil Succession

Question 4

The law simply states that in an underformed sequence of sedimentary rocks, each bed is older than the one above it and younger than the one below.

Answer 4

Law of Superposition

Question 5

This law states that layers of sediment are generally deposited in a horizontal position.

Answer 5

Law of Original Horizontality

Question 6

By using the law of original horizontality, any tilting or deformation must have occurred ____________ the deposition.

Answer 6

After

Question 7

This law states that sediments extend laterally in all directions until terminating against the edge of a basin or thinning and pinching out (as in a facies change).

Answer 7

Law of Lateral Continuity

Question 8

This law states that intrusions or faults are younger than the rocks that they intruded or displaced.

Answer 8

Law of Cross-Cutting Relationships

Question 9

This law states that inclusions, or fragments of rock, contained within a rock layer are older than the rock layer itself.

Answer 9

Law of Inclusion

Question 10

This principle states that fossil organisms succeed one another in a definite and determinable order, and therefore any time period can be recognized by its fossil content.

Answer 10

Principle of Fossil Succession

Question 11

These fossils are widespread geographically and are limited to a short span of geologic time.

Answer 11

Index Fossils

Question 12

The presence of ________ _________ provides an important method of matching rocks of the same age rock formations.

Answer 12

Index Fossils

Question 14

It is essential to know the direction of younging, that is, the direction through the layers towards younger rocks. The direction of younging can be determined by small-scale features that indicate the way-up of the beds or by using other stratigraphic techniques to determine the order of formation.

Answer 14

Deformed Strata

Question 15

Are those that have been deposited essentially without interruption or no gap in the rock record.

Answer 15

Conformable beds/strata

Question 16

True or False:

There are places on Earth that has a complete set of conformable strata.

Answer 16

False, there are no place on Earth that has a complete set of conformable strata.

Question 17

An ______________ represents a long period during which deposition ceased, erosion removed previously formed rocks, and then deposition resumed. In each case, uplift and erosion are followed by subsidence andrenewed sedimentation.

Answer 17

Unconformity

Question 18

It is the interval of geologic time not represented by strata.

Answer 18

Hiatus

Question 19

A short interruption in deposition with little or no erosion before resumption of sedimentation.

Answer 19

Diastem

Question 20

What are the three types of unconformities?

Answer 20

Disconformities, Angular Unconformities, and Nonconformity

Question 21

A surface of erosion or non-deposition between younger and older beds that are parallel to each other (may be difficult to recognize; gaps in fossil record can be a clue.)

Answer 21

Disconformities

Question 22

An unconformity in which the beds are at an angle to each other (one or both may be tilted, but they are not parallel to each other).

Answer 22

Angular Unconformities

Question 23

Are eroded metamorphic or igneous rocks are covered by sedimentary rocks (if intrusion, sed rocks older, if non conformity, ig/met rocks older).

Answer 23

Nonconformity