Earth Science Lab Final (Answered) Complete
Verified Solution
Noncomformity
1) Younger sedimentary rocks on top of older metamorphic or intrusive igneous rocks
2) Imply period of uplift of deeply buried rocks
Three types of uncomformities
angular uncomformity, disconformity, and noncomformity
Radiocarbon dating
Using the carbon-14 isotope to date very recent events
(Half-life of carbon-14 is only 5,730 years)
(Only useful for dating events from historic past and very recent geologic history
because Carbon-14 is present in small amounts in all organisms)
Divisions within the geologic time scale
1) eons divided into --> eras (Phanerozoic includes Paleozoic, Mesozoic, and Cenozoic)
2) eras divided into --> periods
3) Periods divided into --> epochs
Types of rock deformation
1) elastic deformation: stress is gradually applies and rocks return to original size and
shape whens tress is removed
ductile and brittle deformation happen when elastic limit is surpassed
2) Brittle deformation: results in fractures and common at/near the surface
3) Ductile deformation: solid-state flow at great depths, produces a change in the size
and shape of a rock, some chemical bonds break and new ones form
____ structures formed by ductile deformation and are wavelike undulations that
form when rocks bend under compression.
folds
types of folds
1) symmetrical fold: Limbs are mirror images
2) asymmetrical fold: Limbs are different
3) overturned fold: One or both limbs are tilted beyond the vertical
____ allows scientists to accurately determine numerical ages for rocks
representing important events in Earth's past.
radiometric dating
______ are determined placing rocks in the proper sequence of formation
(comparing it to the others' ages)
relative dating
, Principle of superposition
Older layers of sediment will be on the bottom and the younger layers will be on the top
1) In an undeformed sequence of sedimentary rocks, each bed is older than the one
above and younger than the one below
2) Also applies to lava flows and ash beds
3) developed by Nicolas Steno in the mid 1600s
Principle of original horizontality
1) Layers of sediment are generally deposited in a horizontal position
2) Rock layers that are flat have not been disturbed
3) Folded or inclined rocks must have been disrupted after deposition
4) Sedimentary layers laid down first and destructive event caused these layers to fold
Principle of Lateral Continuity
1) Sedimentary beds originate as continuous layers that extend in all directions
2) Identical strata on two sides of a canyon were continuous before the canyon was
carved
Principle of Cross-cutting relationships
1) Geologic features that cut across rocks must form after the rocks they cut through
2) Faults, igneous intrusions
Inclusions
1) Fragments of one rock unit enclosed within another
2) Rock that contains inclusions is younger than the rock that provided the inclusions
Uncomformities
1) Interrupting the deposition of sediment creates a break in the rock record called an
unconformity
2) Represents a period when deposition stopped, erosion occurred, and then deposition
resumed
3) Generally, uplift causes deposition to stop and subsidence causes deposition to
resume
angular uncomformity
1) Consists of tilted or folded sedimentary rocks overlain by younger, more flat lying
strata
2) Deformation occurred during the time that deposition stopped
Disconformity
Verified Solution
Noncomformity
1) Younger sedimentary rocks on top of older metamorphic or intrusive igneous rocks
2) Imply period of uplift of deeply buried rocks
Three types of uncomformities
angular uncomformity, disconformity, and noncomformity
Radiocarbon dating
Using the carbon-14 isotope to date very recent events
(Half-life of carbon-14 is only 5,730 years)
(Only useful for dating events from historic past and very recent geologic history
because Carbon-14 is present in small amounts in all organisms)
Divisions within the geologic time scale
1) eons divided into --> eras (Phanerozoic includes Paleozoic, Mesozoic, and Cenozoic)
2) eras divided into --> periods
3) Periods divided into --> epochs
Types of rock deformation
1) elastic deformation: stress is gradually applies and rocks return to original size and
shape whens tress is removed
ductile and brittle deformation happen when elastic limit is surpassed
2) Brittle deformation: results in fractures and common at/near the surface
3) Ductile deformation: solid-state flow at great depths, produces a change in the size
and shape of a rock, some chemical bonds break and new ones form
____ structures formed by ductile deformation and are wavelike undulations that
form when rocks bend under compression.
folds
types of folds
1) symmetrical fold: Limbs are mirror images
2) asymmetrical fold: Limbs are different
3) overturned fold: One or both limbs are tilted beyond the vertical
____ allows scientists to accurately determine numerical ages for rocks
representing important events in Earth's past.
radiometric dating
______ are determined placing rocks in the proper sequence of formation
(comparing it to the others' ages)
relative dating
, Principle of superposition
Older layers of sediment will be on the bottom and the younger layers will be on the top
1) In an undeformed sequence of sedimentary rocks, each bed is older than the one
above and younger than the one below
2) Also applies to lava flows and ash beds
3) developed by Nicolas Steno in the mid 1600s
Principle of original horizontality
1) Layers of sediment are generally deposited in a horizontal position
2) Rock layers that are flat have not been disturbed
3) Folded or inclined rocks must have been disrupted after deposition
4) Sedimentary layers laid down first and destructive event caused these layers to fold
Principle of Lateral Continuity
1) Sedimentary beds originate as continuous layers that extend in all directions
2) Identical strata on two sides of a canyon were continuous before the canyon was
carved
Principle of Cross-cutting relationships
1) Geologic features that cut across rocks must form after the rocks they cut through
2) Faults, igneous intrusions
Inclusions
1) Fragments of one rock unit enclosed within another
2) Rock that contains inclusions is younger than the rock that provided the inclusions
Uncomformities
1) Interrupting the deposition of sediment creates a break in the rock record called an
unconformity
2) Represents a period when deposition stopped, erosion occurred, and then deposition
resumed
3) Generally, uplift causes deposition to stop and subsidence causes deposition to
resume
angular uncomformity
1) Consists of tilted or folded sedimentary rocks overlain by younger, more flat lying
strata
2) Deformation occurred during the time that deposition stopped
Disconformity
