6/14/25, 12:43 PM EES 220 Exam 2
EES ACTUAL EXAM 2 2025-2026 \NEWEST VERSION
|COMPLETE QUESTIONS AND ACCURATE DETAILED
ANSWERS \VERIFIED ANSWERS \ACTUAL EXAM
GRADED A+
What's the difference between Relative dating gives the age of rocks in reference
relative and absolute dating? to the rocks around it while absolute dating gives
an exact number of years
principle of superposition oldest rocks are deposited on the bottom and newer on top
rock layers are initially deposited horizontally. Any
principle of original
horizontality discrepancies with this occurred after the layers were
deposited
rocks are deposited in continuous sheets until they
principle of original continuity
taper out or are cut off. This is why layers often inter
finger
principle of cross-cutting if one geologic feature cuts across another, the feature that has
relationships been cut is older
principle of inclusions inclusions are older than the material that surrounds them
unconformities markers of unrecorded time in the geologic record *usually
markers of erosion
rock layers are turned at an
angle with other rock deposited
angular unconformity
on top of it
nonconformity sedimentary rock deposited on top of eroded igneous or
metamorphic rock
disconformity sedimentary rock deposited on other sedimentary rock that has
been eroded
specific fossil species are only found in a limited
How are fossils used to
interval of strata, so they can be traced back to when
determine the relative age
that species was around or related to dated rocks in
of sedimentary rocks?
other regions the have the same fossils (principle of
fossil succession)
fossils that occupy a short span of time. Ones with a
index fossils
/ 1/1
3
, 6/14/25, 12:43 PM EES 220 Exam 2
large geographic range are more useful for
correlating strata
number of protons in an atom (# on bottom)
atomic number
number of protons and neutrons
in an atom (# on top)
Atomic mass
atomic weight average mass # of isotopes in a naturally occurring element
atoms of the same element, but
having different mass numbers
isotope
(different number of neutrons)
What makes some atoms if there are too many neutrons or too few protons, the
unstable and more prone to atom is unstable and more prone to decay
radioactive decay?
the unstable parent isotope releases an alpha particle
from the nucleus, changing into a whole new element
alpha decay
(stable daughter). This decreases the atomic mass by 4
and the atomic # by 2) Ex: U238 forms Th234 and
continues changing to finally become Pb206 (only form
of decay that will change atomic mass*)
parent isotope loses an electron (proton and electron
beta decay
split apart, turning a neutron into a proton), causing
the atomic number to increase by 1. Ex: Rb 87 forms Sr
87
parent isotope gains an electron (proton and electron combine
electron capture
in the nucleus,
creating a neutron), causing the atomic number to decrease 1. Ex:
K40 forms Ar40
What is the 1/2 life of a The time that it takes for half of the parent isotopes to decay into
radioactive isotope? daughter isotopes
T 1/2= 47 billion yrs, beta decay, materials: mica,
87Rb - 87 Sr
feldspar, amphibole, and whole rocks
40K - 40 Ar T 1/2= 1.3 billion yrs, electron capture, mica, feldspar, amphibole,
and whole rocks
T 1/2= 4.5 billion years, many types of decay including
238U - 206 Pb
alpha, materials: Zircon and U- bearing materials
/ 2/1
3
EES ACTUAL EXAM 2 2025-2026 \NEWEST VERSION
|COMPLETE QUESTIONS AND ACCURATE DETAILED
ANSWERS \VERIFIED ANSWERS \ACTUAL EXAM
GRADED A+
What's the difference between Relative dating gives the age of rocks in reference
relative and absolute dating? to the rocks around it while absolute dating gives
an exact number of years
principle of superposition oldest rocks are deposited on the bottom and newer on top
rock layers are initially deposited horizontally. Any
principle of original
horizontality discrepancies with this occurred after the layers were
deposited
rocks are deposited in continuous sheets until they
principle of original continuity
taper out or are cut off. This is why layers often inter
finger
principle of cross-cutting if one geologic feature cuts across another, the feature that has
relationships been cut is older
principle of inclusions inclusions are older than the material that surrounds them
unconformities markers of unrecorded time in the geologic record *usually
markers of erosion
rock layers are turned at an
angle with other rock deposited
angular unconformity
on top of it
nonconformity sedimentary rock deposited on top of eroded igneous or
metamorphic rock
disconformity sedimentary rock deposited on other sedimentary rock that has
been eroded
specific fossil species are only found in a limited
How are fossils used to
interval of strata, so they can be traced back to when
determine the relative age
that species was around or related to dated rocks in
of sedimentary rocks?
other regions the have the same fossils (principle of
fossil succession)
fossils that occupy a short span of time. Ones with a
index fossils
/ 1/1
3
, 6/14/25, 12:43 PM EES 220 Exam 2
large geographic range are more useful for
correlating strata
number of protons in an atom (# on bottom)
atomic number
number of protons and neutrons
in an atom (# on top)
Atomic mass
atomic weight average mass # of isotopes in a naturally occurring element
atoms of the same element, but
having different mass numbers
isotope
(different number of neutrons)
What makes some atoms if there are too many neutrons or too few protons, the
unstable and more prone to atom is unstable and more prone to decay
radioactive decay?
the unstable parent isotope releases an alpha particle
from the nucleus, changing into a whole new element
alpha decay
(stable daughter). This decreases the atomic mass by 4
and the atomic # by 2) Ex: U238 forms Th234 and
continues changing to finally become Pb206 (only form
of decay that will change atomic mass*)
parent isotope loses an electron (proton and electron
beta decay
split apart, turning a neutron into a proton), causing
the atomic number to increase by 1. Ex: Rb 87 forms Sr
87
parent isotope gains an electron (proton and electron combine
electron capture
in the nucleus,
creating a neutron), causing the atomic number to decrease 1. Ex:
K40 forms Ar40
What is the 1/2 life of a The time that it takes for half of the parent isotopes to decay into
radioactive isotope? daughter isotopes
T 1/2= 47 billion yrs, beta decay, materials: mica,
87Rb - 87 Sr
feldspar, amphibole, and whole rocks
40K - 40 Ar T 1/2= 1.3 billion yrs, electron capture, mica, feldspar, amphibole,
and whole rocks
T 1/2= 4.5 billion years, many types of decay including
238U - 206 Pb
alpha, materials: Zircon and U- bearing materials
/ 2/1
3
