Laboratory Manual in Physical Geology
Vocabulary: Lab 8 Exam With 100%
Correct Answers
Geologic record - correct answers ✔✔The division of Earth's history into time periods, grouped
into three eons—Archaean, Proterozoic, and Phanerozoic—and further subdivided into eras,
periods, and epochs. Has youngest being on top and getting older as it goes down by layers
Fossils - correct answers ✔✔Any evidence of ancient life
Relative age dating - correct answers ✔✔Determines when something formed or happened in
relation to other things; Ex: younger brother by saying you are older than him
Absolute age dating - correct answers ✔✔Process of determining when something formed or
happened in exact units of time such as days, months or years. Ex: Younger brother by saying he
is 3 years younger than me
Formations - correct answers ✔✔Mappable units; can be subdivided into "members"-individual
strata
Law of Original Horizontality - correct answers ✔✔Sedimentary layers (strata) and lava flows
were originally deposited as relatively horizontal sheets; if they are no longer flat, it is because
they have been displaced by subsequent movements of Earth's crust
Strata - correct answers ✔✔Sedimentary layers
Law of Lateral Continuity - correct answers ✔✔Lava flows and strata extend laterally in all
directions until they thin to nothing (pinch out) or reach the due of their basin deposition
, Law of Superposition - correct answers ✔✔In an undistributed sequence of strata or lava flows,
the oldest layer is at the bottom of the sequence and the youngest is at the top
Law of Inclusions - correct answers ✔✔Any piece of rock (clast) that has become included in
another rock or body of sediment must be older than the rock or sediment which it has been
incorporated; such a clast is called an inclusion. The surrounding body of rock is called the
matrix. An inclusion is older than its surrounding matrix
Inclusion - correct answers ✔✔Usually a rock fragment, crystal, or fossil that follows the law of
inclusions
Matrix (or groundmass) - correct answers ✔✔The surrounding body of rock
Law of Cross-Cutting - correct answers ✔✔Any feature that cuts across a rock or body of
sediment must be older than the rock or sediment that cuts across; such features include
fractures (cracks in rock), faults (fractures along which movement has occurred), or masses of
magma that cut across pre-existing rocks before they cooled. When a body of magma intrudes
pre-existing rocks, a narrow zone of metamorphism usually form in the pre-existing rocks
adjacent to the intrusion
Law of Unconformities - correct answers ✔✔Surfaces called unconformities represent gaps in
the geologic record the formed wherever layers were not deposited for a time or else layers
were removed by erosion an unconformity is a rock surface that represent a gap in the geologic
record
Disconformity - correct answers ✔✔An unconformity between parallel strata or lava flows; most
are irregular surfaces and pieces of the underlying rock are often included in the strata above
them
Vocabulary: Lab 8 Exam With 100%
Correct Answers
Geologic record - correct answers ✔✔The division of Earth's history into time periods, grouped
into three eons—Archaean, Proterozoic, and Phanerozoic—and further subdivided into eras,
periods, and epochs. Has youngest being on top and getting older as it goes down by layers
Fossils - correct answers ✔✔Any evidence of ancient life
Relative age dating - correct answers ✔✔Determines when something formed or happened in
relation to other things; Ex: younger brother by saying you are older than him
Absolute age dating - correct answers ✔✔Process of determining when something formed or
happened in exact units of time such as days, months or years. Ex: Younger brother by saying he
is 3 years younger than me
Formations - correct answers ✔✔Mappable units; can be subdivided into "members"-individual
strata
Law of Original Horizontality - correct answers ✔✔Sedimentary layers (strata) and lava flows
were originally deposited as relatively horizontal sheets; if they are no longer flat, it is because
they have been displaced by subsequent movements of Earth's crust
Strata - correct answers ✔✔Sedimentary layers
Law of Lateral Continuity - correct answers ✔✔Lava flows and strata extend laterally in all
directions until they thin to nothing (pinch out) or reach the due of their basin deposition
, Law of Superposition - correct answers ✔✔In an undistributed sequence of strata or lava flows,
the oldest layer is at the bottom of the sequence and the youngest is at the top
Law of Inclusions - correct answers ✔✔Any piece of rock (clast) that has become included in
another rock or body of sediment must be older than the rock or sediment which it has been
incorporated; such a clast is called an inclusion. The surrounding body of rock is called the
matrix. An inclusion is older than its surrounding matrix
Inclusion - correct answers ✔✔Usually a rock fragment, crystal, or fossil that follows the law of
inclusions
Matrix (or groundmass) - correct answers ✔✔The surrounding body of rock
Law of Cross-Cutting - correct answers ✔✔Any feature that cuts across a rock or body of
sediment must be older than the rock or sediment that cuts across; such features include
fractures (cracks in rock), faults (fractures along which movement has occurred), or masses of
magma that cut across pre-existing rocks before they cooled. When a body of magma intrudes
pre-existing rocks, a narrow zone of metamorphism usually form in the pre-existing rocks
adjacent to the intrusion
Law of Unconformities - correct answers ✔✔Surfaces called unconformities represent gaps in
the geologic record the formed wherever layers were not deposited for a time or else layers
were removed by erosion an unconformity is a rock surface that represent a gap in the geologic
record
Disconformity - correct answers ✔✔An unconformity between parallel strata or lava flows; most
are irregular surfaces and pieces of the underlying rock are often included in the strata above
them
