3. 3
Radioisotopic/radiometric dating
Many believe in an old earth, i.e., billions
of years old, due to radioisotopic dating
But is this really the case? Is it true that
the earth is billions of years old?
6. 6
Three Types of Radioisotopic
Decay
Gamma radiation – photon of light emitted;
atom does not lose mass
Alpha radiation – alpha particle has mass;
when decay happens atom loses mass
7. 7
Half-life
Parent – the original radioactive element
Daughter- the resulting element(s) from radioisotopic
decay, or series of decay
Half-life – the amount of time it takes for parent to decay
to 50:50 parent/daughter ratio; e.g., 1,000,000 atoms of
238U would take 4.5 billion years to get 500,000 atoms
each of 238U and 206Pb (one half-life); and second 4.5
billion yrs would result in 250,000 atoms of 238U and
750,000 atoms of 206Pb (two half-lives)
8. 8
Half-life
Parent – the original radioactive element
Daughter- the resulting element(s) from radioisotopic
decay, or series of decay
Half-life – the amount of time it takes for parent to decay
to 50:50 parent/daughter ratio; e.g., 1,000,000 atoms of
238U would take 4.5 billion years to get 500,000 atoms
each of 238U and 206Pb (one half-life); and second 4.5
billion yrs would result in 250,000 atoms of 238U and
750,000 atoms of 206Pb (two half-lives)
At this time, unknown what causes an individual
radioactive atom to decay while another does not
13. 13
The late Willard F. Libby led team of scientists at University of Chicago
during the post-II War period.
1949 first measured rate of 14C decay at 5568 ± 30years
1960 Libby received the Nobel Prize in Chemistry
Half-life revised to 5730 ± 40 years (Cambridge half-life)
1950’s used Gas Proportional Counting to measure 14C
Liquid Scintillation Counting (LSC) uses benzene, acetylene, ethanol,
methanol, and other chemicals.
Mid-1970’s development of Accelerated Mass Spectroscopy (AMS)
The Atomic Mass Number is the sum of the number of protons and
neutrons
Carbon 14
14. 14
National Ocean Sciences AMS at Woods Hole Oceanographic
Institution, Massachusetts. Photograph of Staff Physicist Robert
Schneider placing a carousel of graphite targets into the ion source of
the accelerator.
Photo by Tom Kleindinst, 1995
15. 15
Air/atmosphere carbon molecules:
98.89% 12C
1.11%13C
0.0000000001% 14C, or 1 14C for
every 1,000,000,000,000 12C
16. 16
Air/atmosphere carbon molecules:
98.89% 12C
1.11%13C
0.0000000001% 14C, or 1 14C for
every 1,000,000,000,000 12C
12C is stable
17. 17
Air/atmosphere carbon molecules:
98.89% 12C
1.11%13C
0.0000000001% 14C, or 1 14C for
every 1,000,000,000,000 12C
12C is stable
13C is stable
18. 18
Air/atmosphere carbon molecules:
98.89% 12C
1.11%13C
0.0000000001% 14C, or 1 14C for
every 1,000,000,000,000 12C
12C is stable
13C is stable
14C is unstable; 14C changes back into 14N
19. 19
Air/atmosphere carbon molecules:
98.89% 12C
1.11%13C
0.0000000001% 14C, or 1 14C for
every 1,000,000,000,000 12C
12C is stable
13C is stable
14C is unstable; 14C changes back into 14N
Entire inventory of 14C is called the carbon
exchange reservoir.
29. 29
Known limitations
Size of sample is important.
the larger the better
purification and distillation removes some matter
(LSC)
AMS better able to handle smaller samples
Requires great care in collecting and packaging.
Carbon sample location requires careful stratigraphic
examination.
Upper practical limit of 40,000 – 50,000 years, or 9 -10
half-lives.
Atmospheric 14C /12C ratio not always constant.
In general, single dates should not be trusted. Whenever
possible multiple samples should be collected and dated
from associated strata.
(http://id-
archserve.ucsb.edu/Anth3/Courseware/Chronology/08_Radiocarbon_Dating.html#C14Process)
30. 30
Other factors affecting 14C dating
Plants may discriminate against intake of
14C; plants are known to discriminate
against 13C1
1
. www.plantphys.net/article.php?ch=9&id=135
31. 31
Other factors affecting 14C dating
Plants may discriminate against intake of
14C; plants are known to discriminate
against 13C1
Reservoir effects
1
. www.plantphys.net/article.php?ch=9&id=135
32. 32
Other factors affecting 14C dating
Plants may discriminate against intake of
14C; plants are known to discriminate
against 13C1
Reservoir effects
Suess or Industrial effect
1
. www.plantphys.net/article.php?ch=9&id=135
33. 33
Other factors affecting 14C dating
Plants may discriminate against intake of
14C; plants are known to discriminate
against 13C1
Reservoir effects
Suess or Industrial effect
Atomic bomb effect
1
. www.plantphys.net/article.php?ch=9&id=135
34. 34
Other factors affecting 14C dating
Plants may discriminate against intake of
14C; plants are known to discriminate
against 13C1
Reservoir effects
Suess or Industrial effect
Atomic bomb effect
Noah’s flood
1
. www.plantphys.net/article.php?ch=9&id=135
35. 35
14C in coal
C14 found in coal supposedly millions of
years old
37. 37
14C in diamonds
Diamonds are believed to have formed 1-3
billion years ago
The earth’s mass is about 6x1027 g, which
would be equivalent to about 4.3x1026
atoms of 14C
It takes 88 half-lives to get to a single atom
of 14C
88 half-lives is about 500,000 years.
38. 38
The presence of 14C in supposedly
ancient coal, fossil wood, and diamonds
falsifies the notion that the rocks or strata
in which they were found are millions or
years old.
42. 42
K-Ar dating
Parent daughter
40K 40Ar
40Ca
Half-life of 40K is 1.26 billion years.
40Ca is rarely used to determine dates
because it is hard to determine the
quantity of calcium initially present.
43. 43
K-Ar dating
Parent daughter
40K 40Ar
40Ca
Half-life of 40K is 1.26 billion years.
40Ca is rarely used to determine dates
because it is hard to determine the
quantity of calcium initially present.
11.2% of 40K decays to 40Ar
44. 44
K-Ar dating
Parent daughter
40K 40Ar
40Ca
Half-life of 40K is 1.26 billion years.
40Ca is rarely used to determine dates
because it is hard to determine the
quantity of calcium initially present.
11.2% of 40K decays to 40Ar
88.8% of 40K decays to 40Ca
45. 45
Whole rock dating – the whole of the rock sample is
crushed and dated
Partial rock dating – rocks are generally composed of
different minerals; these different minerals have
different structures and radioisotopes behave differently
in each mineral
Note: radioisotopic dating is usually done on igneous and
volcanic rock. Metamorphic and sedimentary rocks are
considered less suitable for dating because their origin is
already preexisting and re-worked rock
46. 46
Date calculation:
t = h x ln[1 + (40Ar)/(0.112 x (40K))]/ln(2)
where:
t = time in years
h = half-life in years
ln = natural logarithm
47. 47
Atmosphere (air) contains 40Ar
-some air 40Ar may be trapped in rocks
-ratio of 40Ar to 39Ar in air is well known at
295:1
-measuring 39Ar and 40Ar, and applying
the ratio one can subtract off air-40Ar
48. 48
Measured K-Ar, Mt. St. Helens
http://www.answersingenesis.org/tj/v10/i3/argon.asp
49. 49
Measured K-Ar, Mt. St. Helens
Lava solidified in 1986
http://www.answersingenesis.org/tj/v10/i3/argon.asp
50. 50
Measured K-Ar, Mt. St. Helens
Lava solidified in 1986
340,000 years ± 600 yrs
http://www.answersingenesis.org/tj/v10/i3/argon.asp
51. 51
Measured K-Ar, Mt. St. Helens
Lava solidified in 1986
340,000 years ± 600 yrs
2,800,000 yrs ± 600,000 yrs
http://www.answersingenesis.org/tj/v10/i3/argon.asp
52. 52
Measured K-Ar, Mt. St. Helens
Lava solidified in 1986
340,000 years ± 600 yrs
2,800,000 yrs ± 600,000 yrs
Critics claim excess Ar, which is known about
http://www.answersingenesis.org/tj/v10/i3/argon.asp
53. 53
Measured K-Ar, Mt. St. Helens
Lava solidified in 1986
340,000 years ± 600 yrs
2,800,000 yrs ± 600,000 yrs
Critics claim excess Ar, which is known about
Biblical creationists question whether dating
works on rocks of unknown ages when it does
not work on rocks of known age
http://www.answersingenesis.org/tj/v10/i3/argon.asp
56. 56
Decay rate did not change when subject to
extreme changes in temperature,
pressure, magnetism, electrical fields and
chemical alteration.
57. 57
Constant decay rate?
Anderson and Spangler showed decay process is not random,
therefore, concluded that decay rate is uncertain, putting all
radiometric dating into serious question.
Working with Cobalt 60 and Cesium 137 they state “The evidence is
inconsistent with the theory of decay independence.”1 Cobalt 60
was significantly influenced by electrical field.
“…even though holding responsible scientific positions, these
authors admitted to difficulty in getting their work published and
since then have confessed that it has been ‘disregarded, discounted,
disbelieved…by virtually the entire scientific community’ (Anderson
and Spangler, 1974)”2
1 Quoted in Note 11, In the Minds of Men, Ian T. Taylor, TFE Publishing:Toronto, Canada, 3rd edition,
fifth reprint 1994; p. 457.
2 Taylor, ibid., p. 296.
58. 58
In cautiously worded terms Anderson and Spangler
“writing in American Physical Society Bulletin, 1971,
10:1180 had presented their data to show that the
gamma emission rate of cobalt 60 was significantly
influenced by electrical fields. They concluded that, in
this case, radioactive decay is not independent.” 1
In 1974, the authors freely expressed their views more
explicitly in the, now defunct, journal Pensée.
1 Taylor, op cit., p.457.
59. 59
Rhenium-187 1
-half-life of 42 billion years
-half-life of 33 years when stripped of electrons
-isolated case
1. Don DeYoung, Thousands…Not Billions, p. 144, with reference to Kerr,
Richard, 1999, Tweaking the Clock of Radioactive Decay, Science 286(5441),
882-883.
60. 60
Solar neutrinos
-seasonal fluctuations
-rates increased when closer to the sun and
decreased when farther from the sun
Brian Thomas, http://www.icr.org/articles/radioactive-decay-rates-not-stable, article
posted August 4, 2009; referencing Mullins, J., 2009, Solar ghosts may haunt
Earth’s radioactive atoms, New Scientist, 2714:42-45.
61. 61
Cavitation
-shock waves produced from the collapse of
vapour bubbles resulting from extremely fast
water flows
-during a 90-minute experiment, radioactive
thorium decay was accelerated by a factor of
10,000 times
Brian Thomas, http://www.icr.org/articles/radioactive-decay-rates-not-stable, article
posted August 4, 2009; referencing Cardone, F., R. Mignani and a. Petrucci,
2009. Piezonuclear decay of thorium. Physics Letters A. 373 (22): 1956-1958.
62. 62
Radioisotopes not found on earth
Old earth suggested from extinct parent isotopes for
which there is strong evidence that these once existed in
substantial amounts in meteorites, but have since
completely decayed away.
Extinct Isotope Half-life (years)
Plutonium-244 82 million
Iodine-129 16 million
Palladium-107 6.5 million
Manganese-53 3.7 million
Iron-60 1.5 million
Aluminum-26 700,000
Calcium-41 130,000
However, can be interpreted as vast quantity of decay
occurred in the past, not necessarily indicative of age.
64. 64
Deep Earth Zircons
Uranium/lead age of 1.5 billion yrs ± 20 million yrs
Crystals contained too much helium to be million yrs old
Leak rate of helium out of zircon crystals was unknown
Predicted and measured helium leak rates agreed at
~6000 yrs
Helium leak rate concords with Biblical history
D. Russell Humphreys, A Tale of Two Hourglasses, Impact article #402, Institute for Creation
Research, California, December 2006.
67. 67
Some assumptions
Decay rate is constant over the determined time
period
Neither parent nor daughter material has been
added to or taken away from the sample during
the determined time period
69. 69
Some assumptions
Decay rate is constant over the determined time
period
Neither parent nor daughter material has been
added to or taken away from the sample during
the determined time period
The initial parent/daughter ratio is known (i.e., it
is most often assumed to be zero daughter)
70. 70
Argon-Argon
40K-39K ratio appears to be constant in the sample
Sample put in nuclear reactor and bombarded with
neutrons
39K is turned into 39Ar
Assumed that newly formed 39Ar is proportional to 39K
71. 71
Wiens calls this a typical argon-argon plot.
But is it typical? Notice also, the Y-axis on the left hand side. From where does
one obtain the age?
Roger C. Wiens, Radiometric Dating A Christian Perspective, revised 2002. Wiens has a PhD in physics
with a minor in geology. He is a firm believer in the radiometric dating method and believes in an old earth.
72. 72
Isochrons
Iso = same, equal chron = time
Attempts to address issue of initial amount of daughter
material before any parent material had time to decay
Attempts to address issue of addition or subtraction of
external radioisotopic material, i.e., whether or not the
sample remained a closed system
Attempts to address the most likely computed age of a
rock sample, based upon the statistical average of
several radioisotope measurements
77. 77
“It would not be inconsistent with the
scientific evidence to conclude that God
made everything relatively recently, but
with the appearance of great age, just as
Genesis 1 and 2 tell of God making Adam
as a fully grown human (which implies the
appearance of age). The idea of a false
appearance of great age is a philosophical
and theological matter that we won't go
into here. …
Roger C. Wiens, Radiometric Dating A Christian Perspective, revised 2002. Wiens has a PhD in physics with a
minor in geology. He is a firm believer in the radiometric dating method and believes in an old earth.
78. 78
… The main drawback—and it is a strong
one—is that this makes God appear to be
a deceiver. However, some people have
no problem with this. Certainly whole
civilizations have been incorrect
(deceived?) in their scientific and
theological ideas in the past. Whatever the
philosophical conclusions, it is important
to note that an apparent [emphasis added]
old Earth is consistent with the great
amount of scientific evidence.”
Roger C. Wiens, Radiometric Dating A Christian Perspective, revised 2002. Wiens has a PhD in physics with a
minor in geology. He is a firm believer in the radiometric dating method and believes in an old earth.
79. 79
However, if God stated that He created in
six days, but really took millions and
billions of years, would this not make God
a deceiver?
If God really took millions and billions of
years to make the heavens, earth, and all
creatures, but He said He did it in six
days, would this not make God
incompetent at communicating?
80. 80
Age is not directly measured
Amount (or ratio) of parent/daughter, at
the present time, is what is measured
Heat, pressure, water, chemicals can
affect the parent/daughter ratio
81. 81
Other dating methods
Thermoluminescence (TL): when individual grains of common minerals,
such as quartz, are heated, they emit light, and this is related to the
radiation ‘stored’ in the crystal structure. By measuring the light emitted
from the mineral grain when it is heated, and measuring the radiation in
the environment where the grain was found, a date is calculated. It is
assumed that the radiation was slowly absorbed from the environment,
building up from zero at a certain time in the past (perhaps when the grain
was last exposed to sunlight).
Optically-stimulated luminescence (OSL): dates are based on exactly
the same principle and TL. But instead of heating the grain, it is exposed to
light to make it emit its ‘stored’ radiation. The calculated date is based on
the same assumptions, and affected by the same uncertainties, as for TL.
Electron-spin resonance: dates are based on the same principles as TL
and OSL. However, the ‘stored’ radiation in the sample is measured by
exposing it to gamma radiation and measuring the radiation emitted. The
measuring technique does not destroy the ‘stored’ radiation (as does TL
and OSL), so the measurement can be repeated on the same sample. The
calculated date is based on the same assumptions, and affected by the
same uncertainties, as for TL and OSL.
82. 82
Other dating methods cont’d
Thorium-uranium (Th/U) dates are based on measuring the isotopes of
uranium and thorium in a sample. It is known that uranium-238 decays
radioactively to form thorium-230 (through a number of steps, including
through uranium-234). The dating calculation assumes that the thorium
and uranium in the sample are related to each other by radioactive decay.
Furthermore, before a date can be calculated, the initial ratios of
230Th/238U and 234U/238U need to be assumed, and it is also assumed
that there has been no gain or loss of uranium or thorium to/from the
environment—i.e. that the system is ‘closed’. However, the bone and soil
must have been ‘open’ to allow these elements to enter and accumulate.
Protactinium-uranium (Pa/U) dates are based on similar principles as
Th/U dating, but use uranium-235 and protactinium-231 instead. The
isotope 235U decays radioactively to form 231Pa. Again, it is assumed that
the isotopes in the sample are related to each other by radioactive decay.
Also, the initial ration of 231Pa/235U has to be assumed, and it is assumed
that there has been no gain or loss of uranium or protactinium to for from
the environment—i.e. that the system is ‘closed’. Again, any bone sample
containing uranium must have been ‘open’ to allow it to accumulate in the
first place.
87. 87
“When Moses wrote that God created
Heaven and Earth and whatever is in
them in six days, then let this period
continue to have been six days, and
do not venture to devise any
comment according to which six days
were one day. …
Martin Luther cited in E. Plass, What Martin Luther Says: A Practical In-House Anthology
for the Active Christian, Concordia Publishing House, St. Louis, 1991, p. 1523
88. 88
But, if you cannot understand how this
could have been done in six days,
then grant the Holy Spirit the honor
of being more learned than you are.
For you are to deal with the Scripture
in such a way that you bear in mind
that God Himself says what is written.
But since God is speaking, it is not
fitting for you wantonly to turn His
Word in the direction you wish to go.”
Martin Luther cited in E. Plass, What Martin Luther Says: A Practical In-House Anthology
for the Active Christian, Concordia Publishing House, St. Louis, 1991, p. 1523
