Absolute Dating Notes
RECAP:
Relative Dating
Absolute Dating
1. Finding the ____________
Estimating a _________________________
___________________ of events in the
age of an object or substance based
rock record
on scientific analysis.
2. Can only determine
The estimate gives you a
_____________________ or
__________________ of dates, NOT the
____________________________, no
exact age of the rock.
____________________________ values.
Absolute doesn’t mean absolute in
this case.
With new technology, and scientific knowledge, came a new ability to
determine the approximate ______________________ ages of rocks (and fossils)
Dendrochronology
• Dendro- _________________
Chronology: study of ______________________
• Study the rings of a tree to figure out ________________ ______________ it
is, and the _________________________ in each year of growth
• Trees make “_______________” each _________________ of growth.
• Can _______________________ ring patterns in trees to look into the
distant past and look at _________________________.
• Thicker rings = _____________________ climate (more
______________________, ______________ extreme ____________________________)
• Thinner rings=__________________ growing climate, disease, ect.
Radiometric Dating
• Different elements “________________________” (break down into
something else) at different _________________.
• They eject energy and _________________________ into another form of an
element, or a _______________________ element.
• We know how long it takes for about _________________ of an amount of
the material to _______________________
• We just look at the ratio of ______________ material to ________________,
and it tells us the age!
• ____________________-__________________ (t1⁄2) is the amount of time
required for a quantity to fall to half its value as measured at the
beginning of the time period.
• Ex) C14 half-life= 5730 years.
• If you have 50% C14 and 50% N14, then the object is 5730 years
old.
• Radiometric Dating gives a _____________ of ages, not a definite
number!
• Different atoms decay at ___________________ rates. Some decay at
____________________ of years, some _____________________.
Absolute Dating Notes
RECAP:
Relative Dating
Absolute Dating
1. Finding the Relative Order of
Estimating a numerical age of an
events in the rock record
object or substance based on
scientific analysis.
2. Can only determine older or
younger, no numerical values.
The estimate gives you a range of
dates, NOT the exact age of the rock.
Absolute doesn’t mean absolute in
this case.
With new technology, and scientific knowledge, came a new ability to
determine the approximate numerical ages of rocks (and fossils)
Dendrochronology
• Dendro- tree
Chronology: study of time
• Study the rings of a tree to figure out how old it is, and the
conditions in each year of growth
• Trees make “rings” each year of growth.
• Can match ring patterns in trees to look into the distant past and
look at climate.
• Thicker rings = better climate (more precipitation , noextreme
temperatures)
• Thinner rings= poor growing climate, disease, ect.
Radiometric Dating
• Different elements “decay” (break down into something else) at
different rates.
• They eject energy and transform into another form of an element, or
a new element.
• We know how long it takes for about half of an amount of the
material to change
• We just look at the ratio of old material to new and it tells us the age!
• Half-Life (t1⁄2) is the amount of time required for a quantity to fall to
half its value as measured at the beginning of the time period.
• Ex) C14 half-life= 5730 years.
• If you have 50% C14 and 50% N14, then the object is 5730 years
old.
• Radiometric Dating gives a range of ages, not a definite number!
• Different atoms decay at different rates. Some decay at billions of
years, some thousands.