Chronology of Writings
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1510
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Leonardo Da Vinci: Selections from the Notebooks of Leonardo Da Vinci.
In his notebooks Da Vinci ponders fossil seashells and concludes that
they could not have been laid down by the Noachian flood. He wrote:
“If the Deluge had carried the shells for distances of three and
four hundred miles from the sea it would have carried them mixed with
various other natural objects all heaped up together; but even at such
distances from the sea we see the oysters all together and also the
shellfish and the cuttlefish and all the other shells which congregate
together, found all together dead; and the solitary shells are found
apart from one another as we see them every day on the sea-shores.
“And we find oysters together in very large families, among which
some may be seen with their shells still joined together, indicating
that they were left there by the sea and that they were still living
when the strait of Gibraltar was cut through. In the mountains of
Parma and Piacenza multitudes of shells and corals with holes may be
seen still sticking to the rocks…”
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1594
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Loys le Roy: Of the interchangeable course or variety of
things in the Whole world. Le Roy accepted that land and sea could change
places and that mountains could be reduced to plains and vice versa. Le Roy
was vague about actual mechanisms. He can be considered as
a very early uniformitarian.
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1625
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Nathaniel Carpenter: Geography delineated forth in two Bookes
In this early work Carpenter argued that the Flood could not have been
the major agent of geological change,
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1634
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Simon Stevin: Second Book of Geology. Stevin followed up
Le Roy with arguments that wind and water sufficed as primary agents.
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1637
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Rene Descartes: Discours de la Methode. Descartes constructed
a history of the Earth which was quite influential; it was the starting
point for many later cosmogonies. Some of the main points of his system
were that the Earth formed as a fiery ball, that when it cooled a crust
formed over the abyssal waters, and that this crust collapsed, releasing
massive volumes of water.
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1650
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James Ussher: A number of writers calculated the date of creation,
using the Biblical chonologies, astronomical records, and historical
chronologies. Of these, Ussher’s date of 4004 BC is the most famous.
Other dates include 3928 BC (John Lightfoot, AD 1644) and 5529 BC
(Theophilus of Antioch. AD 169).
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1669
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Nicholas Steno: The Produmus. Steno did the basic analysis
of how fossils got embedded in stone. From his field observations
of the Tuscan landscape he concluded that the Flood was important
but did not completely explain the observed geology.
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1681
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Thomas Burnet: Sacred Theory of the Earth.
Burnet’s famous and widely read book reworked Descartes’s speculations
to fit the biblical account. In his conception the antediluvian Earth
was a smooth ovoid. Over time the surface dried out and the abyssal
waters were heated. Eventually the surface cracked, releasing the
abyssal waters in the Noachian flood.
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1691
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John Ray: The Wisdom of God Manifested in the Works of Creation.
Ray reworked Burnet’s cosmogony. One of the notable features of Ray’s
works was the thought he put into possible sources for the waters of the
flood. Ray accepted that there had been continuous interchange between
land and sea.
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1693
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Baron Leibnitz: Protogea. Leibnitz reworked Descartes’s
cosmogony. Protogea was published much later in 1749.
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1695
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John Woodward: An essay toward a Natural History of the Earth.
Woodward came down fairly strongly for the view that the flood was an
act of God that could not be accounted for by normal physical processes.
He also postulated hydrological sorting to account for the ordering of
fossils.
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1696
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William Whiston: A new theory of the Earth…. Whiston
added comets to Burnet’s cosmogony as the source of the waters of the
flood.
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1705
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Robert Hooke: Lectures and Discourse of Earthquakes and
Subterranean Eruptions. Hooke believed that the fossils were the
remains of extinct species and could not be accounted for by the Flood.
“Asking himself how the present areas of land came to be dry, he answers
‘it could be from the Flood of Noah, since the duration of that which
was but about two hundred natural days, or half a year could not afford
time enough for the production and perfection of so many and so great
and full grown shells, as these which are so found do testify; besides
the quantity and thickness of the beds of sand with which they are many
times found mixed, do argue that there must needs be a much longer time
of seas residence of the seas above same, than so short a space can afford.”
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1748
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Benoit de Maillet: Telliamed, or Conversations between an
Indian Philosopher and a French Missionary on the Diminution of
the Sea. Using Descartes’s cosmology, the
assumption that the earth was once entirely flooded, and the
observation that the sea level was dropping three inches per
century near his home, he calculated the age of the earth to be
greater than 2 billion years.
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1771
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Peter Pallas: Observation sur la Formation des Montagnards….
Pallas made extensive observations of Russian mountains. He observed the
results of processes that acted on mountains, e.g. weathering, erosion,
deposition, and the fracturing and upheaval of strata. He argued for
occasional catastrophic events as an origin for mountain building.
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1774
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Comte de Buffon: Epochs of Nature.
Buffon assumed that the earth started molten, measured cooling rates of
iron spheres, scaled up, and calculated the age at ~75,000 years. He
himself was suspicious that this was much too young and, in manuscripts
published after his death, suggested longer chronologies, including one
estimate of nearly 3 billion years.
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1778
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Jean de Luc: Lettres Physique et Morales sur l’Histoire de la
Terre et de l’Homme. De Luc’s work is “transitional between the armchair
speculation of the seventeenth century and the hard-nosed empiricism of the
nineteenth century.” De Luc accepted the biblical account, including the
Noachian flood; however, he assumed that the six days of creation were six
long periods of indefinite duration.
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1778
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John Whitehurst: An inquiry into the Original State of the Earth.
Whitehurst added the notion of drastic tidal action of the moon to
Woodward’s cosmogony.
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1779
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Horace-Benedict de Saussure: Voyages dans les Alpes.
De Saussure made extensive observations of the Alps. He appreciated
that curved strata had originally been laid down as horizontal sheets
and were later deformed.
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1787
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Abraham Werner: Kurze Klassification und Beschreibung der
verschiedener Gebirgsarten. Werner recognized the importance of
successive advance and retreat of the oceans for creating the layers
of the Earth.
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1788
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James Hutton: Theory of the Earth; or, an investigation of the laws
observable in the composition, dissolution and restoration of land upon the
globe. Hutton is traditionally credited with being the father of modern
geology. He was the first modern uniformitarian. Hutton argued that the
Earth was of immense antiquity, cycling through changes via slow processes
sans catastrophes. The last sentence of Hutton’s 1788 work is famous and
is widely quoted:
The result, therefore, of our present enquiry is, that we
find no vestige of a beginning – no prospect of an end.
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1794
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Robert Townson: Philosophy of Mineralogy. Townson was one
of the many catastrophists of the late 18’th and early 19’th century. He
pointed out that fieldwork had revealed that the features of the surface
of the Earth could not be accounted for by a single Creation and catastrophic
flood but rather successions of formation and dramatic change.
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1794
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Richard Sullivan: A View of Nature. Sullivan was another
catastrophist. He wrote:
Thus succeed revolution to revolution. When the masses of shells were
heaped upon the Alps, then in the bosom of the ocean, there must have
been portions of the earth, unquestionably dry and inhabited; vegetable
and animal remains prove it; no stratum hitherto discovered, with other
strata upon it, but has been, at one time or another, the surface.
The sea announces everywhere its different sojournments; and at least
yields conviction that all strata were not formed at the same period.
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1799
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Robert Kirwan: Geological Essays. Kirwan was a scriptural
geologist. Although he mostly followed the biblical account in his
account the formation of the topography of the Earth took several
centuries. Kirwan’s virulent attacks on Hutton had the effect of
making Hutton much better known than he otherwise would have been.
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1812
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James Hall: Transactions of the Royal Society of Edinburgh.
Hall argued that Hutton’s water cycles were insufficient to account for
large tumbled rocks in the Alps. He proposed huge waves on a catastrophic
scale that moved ice and rock.
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1812
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Baron de Cuvier: Discours sur les Revolutions du Globe.
Cuvier was the best known and most influential of the catastrophists.
His extensive researches in the geology of the Paris basin led him to
postulate a series of many global catastrophes.
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1820
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William Buckland: Vindiciae Geologicae. In 1820 Buckland was
a scriptural geologist. Thus he wrote:
Again the grand fact of an universal deluge at no very remote period is proved
on grounds so decisive and incontrovertible, that, had we never heard of
such an event from Scripture, or any other authority, Geology of itself
must have called in the assistance of some such catastrophe, to explain
the phenomena of diluvian action which are universally presented to us,
and which are unintelligible without recourse to a deluge exerting its
ravages at a period not more ancient than that announced in the book
of Genesis.
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1830
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Charles Lyell: Principles of Geology. This was the work
that “won” the catastrophist/uniformitarian debate. Lyell laid down four
principles of uniformity:
Uniformity of law (the natural laws have remained the same)
Uniformity of process (same causes today as in the past)
Uniformity of rate (changes occurred at the same rate as now)
Uniformity of state (the Earth was much the same in the past as it is now)
In modern Geology it is generally recognized that Lyell claimed too much
in the last three principles. Drastic changes, albeit not as all embracing
as those envisioned by the catastrophist, occur from time to time. There
have been significant changes in state due to such factors as declining
strength of the radioactive sources of heat, the acquisition of oxygen as
a major atmospheric component, the colonization of land by life, plate
tectonics, and asteroid bombardment.
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1836
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William Buckland: Geology and Mineralogy considered with
reference to natural Theology. By 1836 Buckland had abandoned the
Noachian flood as a source of major geological change. Instead he
postulated numerous antediluvian catastrophes.
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1852
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Jean Baptiste de Beaumont: Notice sur des Systemes de Montagnes.
De Beaumont was a relatively late catastrophist. He argued that as the Earth
cools its volume slowly reduces. The shrinkage causes the formation of
mountains via catastrophic crumpling of the surface.
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1857
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Hugh Miller: The Testimony of the Rocks.
Miller was a very popular creationist geologist. He believed that the
Noachian flood was a local flood in the Mideast and did not credit the
theory that the Earth was young. On page 324 he wrote:
“No man acquainted with the general outlines of Palaeontology, or the true
succession of the sedimentary formations, has been able to believe, during
the last half century, that any proof of a general deluge can be derived
from the *older* geologic systems, — Palaeozoic, Secondary [Mesozoic], or
Tertiary.”
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1862
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Lord Kelvin: On the Secular Cooling of the Earth.
Using thermodynamic principles and measurements of thermal conductivity of
rocks, Kelvin calculated that the earth consolidated from a molten state
98 million years ago. In 1897, he revised his estimate to 20-40 million
years. Dalrymple says that Kelvin’s estimates were “highly authoritative”
for three decades, but notes that they were challenged by people from
several fields, including T. H. Huxley, John Perry (a physicist), and T.
C. Chamberlain (a geologist). All of them challenged the likelihood of
Kelvin’s assumptions.
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1893
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Charles D. Walcott: Geologic Time, as Indicated by
the Sedimentary Rocks of North America.
Walcott takes a detailed look at
the Paleozoic sediments of the Cordilleran Sea (just east of the Sierra
Nevadas), considering such things as the land area supplying sediments and
the grain sizes of the sediments. He arrived at an estimate of 17.5
million years for the Paleozoic and, based on various other authors’
estimates of relative ages of the other eras, 55 million years for the
earth. |
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1905
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Ernest Rutherford:
In the Silliman Lectures at Yale, Rutherford suggested
using radioactivity as a geological timekeeper. The idea was
good but there were practical problems. Initially little was
known about the physics and chemistry of radioactive elements.
Instrumentation had to be improved. The next
section is a chronology of key events
in working out the age of the Earth using radiometric dating.
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Chronology of Radiometric Dating
Chris Stassen (with much owed to Dalrymple’s
The Age of the Earth)
Thanks also to Richard Harter for much help.
The period 1896-1905 marks the discovery of radioactivity and the
realization that rocks could be dated by radioactive decay.
| 1896 |
A. Henri Becquerel discovers that uranium-bearing compounds emit
invisible rays similar to X-rays. (X-rays had been discovered in
1895 by Wilhelm Roentgen.)
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| 1898 |
Marie and Pierre Curie coin the term “radioactivity,” prove that
radioactivity is a property of atoms (as opposed to molecular
composition), discover radioactivity of thorium, and identify
a few of the intermediate products of the uranium and thorium
decay series.
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| 1902 |
Ernest Rutherford and Frederick Soddy demonstrate the exponential
nature of radioactive decay.
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| 1905 |
In a lecture at Harvard, Ernest Rutherford suggests that
uranium/helium or uranium/lead ratios could theoretically be used to
compute the age of rocks.
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At this point the phenomenon of radioactive decay was still very
poorly understood. The intermediate products and end-products were
not known with certainty. The decay rates were entirely unknown,
except for that of radium (a short-lived intermediate product which
the Curies had identified and isolated). Researchers were unaware
that there can be multiple isotopes of the same element, each with
a different decay rate.
However, this did not prevent geologists from making several
uranium/helium and uranium/lead measurements over the next few years.
In many cases the work was done on rocks whose relative ages were
known independently, in order to assess whether or not the element
ratios correlated with relative age. It was discovered that
uranium/helium is not generally reliable because helium is not
retained consistently.
| 1907 |
B.B. Boltwood takes measurements that indicate lead to be a final
product of uranium decay, for its abundance is strongly correlated
with relative age of uranium-bearing minerals. Boltwood attempts
some simple uranium/lead ages, extrapolating the uranium decay
rate from the assumption of decay equilibrium and the previously
measured radium decay rate. (When a decay series has reached
equilibrium, the ratio of the quantity of elements present is equal
to the ratio of their decay rates.)
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| 1911 |
Arthur Holmes publishes several uranium/lead ages based mostly
on measurements taken by Boltwood and an improved value for the
uranium decay rate. These range from 340 million years (a
Carboniferous sample), to 1,640 million years (a Precambrian sample).
|
Holmes’ calculations are called chemical ages (as opposed to
isotope ages) because they are derived from ratios of elements
without regard to isotopes. In 1911 geologists did not know about
isotopes, or about all of the intermediate decay products in between
uranium and lead, or that lead was also produced by the decay of
thorium. As a result of not compensating for those (then-unknown)
factors, the computed ages are too high.
Even though Holmes’ ages are incorrect, they eventually prove to
be much better estimates than the best ones previously available to
geologists (which were based on non-uniform and unreliable processes
such as rates of sedimentation). Holmes’ ages for Phanerozoic
(Cambrian or later) samples are within 20% of the values given by
modern methods. In the early 1900s, however, Holmes’ results appeared
to be at odds with other methods in common use, and they were not
met with immediate acceptance from all quarters.
| 1913 |
J.J. Thompson observes that neon atoms have two different atomic
weights (20 and 22), using equipment he calls a “positive-ray”
apparatus. The existence of isotopes is confirmed. Unfortunately, it
would take a long time to accumulate significant knowledge on the
isotopes relevant to geological dating. Chemical dating
methods won’t entirely give way to isotope dating methods until
almost 1940.
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| 1917 |
J. Barrell publishes a Phanerozoic time scale based on chemical
ages produced by Holmes (1911), and interpolations involving less
quantitative methods. The divisions in the time scale fall fairly
close to today’s accepted values. For example, Barrell placed the
Cenozoic-Mesozoic (Cretaceous-Tertiary) boundary at 55-65 million
years ago (today’s value: 65 million years ago), and the base of the
Cambrian at 360-540 million years ago (today’s value: 570 million
years ago).
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| 1920 |
F.W. Aston improves upon Thompson’s (1913) positive-ray apparatus,
and invents what he calls a “mass spectrograph.” Using this device,
he discovers a third isotope of neon with atomic weight 21. Aston
devotes the remainder of his life to improving the design and
precision of his device, and over time discovers 212 of the 287
naturally occurring isotopes.
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The early period was one of developing knowledge and technique
and of assessing the ages of individual rocks and formations.
However, researchers were beginning to realize that the same
methods hold promise for assessing the Earth’s age.
Calculating an age for the Earth introduces additional complexity:
even if it is a given that accurate ages for rocks can be obtained,
there is no guarantee that the age of any given rock would be the
age of the Earth. It would be necessary to either find rocks which
formed at the same time as the Earth, or else come up with
dating techniques that could “look back” through more recent
events to the Earth’s formation.
| 1921 |
Henry Russell calculates a maximum chemical age of eight billion
years for the Earth’s crust, based on estimates of its total uranium
and lead content. Using the age of the oldest known (at that time)
Precambrian minerals as a minimum for the Earth’s age, Russell said:
Taking the mean of this and the upper limit found above from the ratio
of uranium to lead, we obtain 4 x 109
years as a rough approximation to the age of the Earth’s crust.
(Russell 1921, quoted in Dalrymple 1991)
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| 1927 |
Arthur Holmes publishes a booklet on the age of the Earth, which
becomes fairly popular. The booklet contains a revised version of
Russell’s calculation, based on different estimates of the total
quantity of uranium and lead in the Earth’s crust. Holmes suggests
that the age of the Earth is between 1.6 and 3 billion years.
Twenty years after the first serious attempts at radioactive-decay
ages (Boltwood 1907), the total number of computed mineral ages is
still small enough that Holmes can summarize them all in one short
table.
|
In between 1921 (Russell’s estimate) and roughly World War II, a
number of similar chemical ages for the Earth’s crust were
computed and published. These include: 3.4 billion years
(Rutherford 1929); 4.6 billion years (Meyer 1937); and
3 to 4 billion years (Starik 1937).
| 1927b |
F.W. Aston makes the first measurements of the isotopic ratios of
“common lead.” At this time it was already known that lead found in
association with uranium had a relatively low atomic weight, but it
seemed that all other lead (known as “common lead”) had the same
atomic weight. (The lighter atomic weight of lead in association
with uranium is due to enrichment in
206Pb from decay of
238U.
206Pb is lighter than the atomic
weight of common lead, which is about 207.2.)
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| 1937 |
Alfred Nier begins to make a series of careful measurements on the
isotopic composition of common lead. He discovers that the isotopic
ratios of common lead can vary significantly, even in cases where
the atomic weight does not. The most common radiogenic lead isotopes —
208Pb
(from 232Th) and
206Pb
(from 238U) —
have on average roughly the same atomic weight as “common lead.” As
long as both are added in approximately equal amounts, the isotopic
composition (relative to 204Pb)
would be changed but the atomic weight would not.
Nier concludes that the variations in isotopic composition of
“common lead” are due to mixture in varying degrees between radiogenic
lead and “primeval” lead (which existed in a fixed, but at this point
in time unknown, isotopic ratio at the time of formation of the Earth).
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| 1941 |
Alfred Nier obtains and measures some ancient Pb ores which have the
lowest
207Pb/204Pb and
206Pb/204Pb
ratios of any rocks found to date.
(204Pb is not produced by radioactive
decay, while all other stable isotopes of lead are. The lower the
ratio of other lead isotopes to 204Pb,
the less radiogenic lead is present.) Nier speculates that these
represent approximately the “primeval” Pb isotope ratios.
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| 1941b |
E. Gerling uses Nier’s (1941) “primeval” lead isotope ratios to create
lead isotopic growth curves, and uses these to estimate a minimum age
for the Earth’s crust of 3.2 billion years. In doing so, Gerling
devises the basic technique which will eventually produce an accurate
age for the Earth and solar system.
Unfortunately, Gerling’s original calculations are incorrect primarily
because Nier’s ancient lead ore is not truly “primeval” in composition.
Though Gerling’s result is within 30% of the actual age of the Earth,
it is merely a good measurement of the age of Nier’s samples rather
than the age of the planet itself.
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| 1944 |
During World War II, intense research on the atomic bomb leads to
fantastic improvements in equipment for identifying and analyzing
isotopes. It becomes possible to detect minute quantities of
specific isotopes, and to measure their abundance with high precision.
|
| 1946 |
Alfred Nier improves on the design of the mass spectrometer and his
machine shop builds dozens of the devices. The widespread availability
of this equipment allows a much larger number of researchers to enter
into the study of isotope geology. By the early 1950s, universities
all over the world have laboratories dedicated to performing isotopic
age assessments.
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| 1946b |
Arthur Holmes produces calculations based on Nier’s (1941) data.
Holmes was unaware of Gerling’s (1941b) work and attempted a slightly
different technique. Holmes’ computations result in a wide range
of values; when plotted on a histogram, an obvious peak in the
measurements occurs at about 3.3 billion years (a figure similar to
Gerling’s).
Holmes’ computation involves the assumption that lead on Earth had
been separated once long ago and the individual units had been allowed
to evolve along independent isotopic growth curves. Due to that
assumption being incorrect, Holmes mis-interprets scatter around a
single growth curve as a number of independent growth curves. His
work on tracing the “independent” curves back to their mutual
intersection does not yield meaningful results.
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| 1946c |
F. Houtermans independently performs calculations that are similar to
Holmes’ (1946b) and flawed in essentially the same way. His work is
noteworthy in that he is the first to emphasize that the data on different
isotopic growth curves would be co-linear if they started at the same
point, and for these lines he coins the term “isochrones” (now known as
“isochrons“).
|
By 1946 equipment and understanding of the decay process are
sufficiently mature to generate an accurate assessment of the age of
the Earth. It had been amply established that isotope dating can yield
precise and meaningful results. However, the major remaining problem
is still the same as that of almost thirty years prior: exactly how
to apply the techniques, and what to apply them to, in order to obtain
an age for the Earth.
The evaluation of lead isotopic growth curves (somewhat unfairly
to Gerling, known as the Holmes-Houtermans Model) holds promise, for
it can look back through recent events to a point of origin.
However, the key — and still missing — data needed in order to use
such a method would be the lead isotopic ratios at the time of the
Earth’s formation (i.e., that of “primeval” lead).
| 1953 |
Clair C. Patterson produces accurate “primeval” lead isotopic
measurements from minerals of the Canyon Diablo meteorite which
contain very little (less than ten parts per billion) uranium.
Meteorites provide the final solution to the puzzle, for they
both are “rocks which formed at the same time as the Earth,”
and provide the important data which allows lead isotope
computations to look back to the formation of the Earth. There
had previously been no way to directly assess the age of the Earth;
once meteorites were involved, suddenly there were several
independent means.
In a recent issue of the Caltech Alumni Magazine, Clair
Patterson discussed the ideas that led up to the measurement:
[Harrison] Brown had worked out this concept that the lead in iron
meteorites was the kind of lead that was in the solar system when
it was first formed, and that it was preserved in iron meteorites
without change from uranium decay, because there is no uranium in
iron meteorites. […]
There are two isotopes of uranium that decayed to two different
isotopes of lead, and there’s also thorium, which decays to another
isotope of lead. So you have three different isotopes of lead. And
the whole thing gets mixed up. You’ve got all these separate age
equations for the different isotopes of uranium and different isotopes
of lead that were formed. […] If we only knew what the
isotopic composition of primordial lead was in the Earth at the time
it formed, we could take that number and stick it into this marvelous
equation that the atomic physicists had worked out. And you could
turn the crank and blip–out would come the age of the Earth.
(Patterson 1997)
|
| 1953b |
F.G. Houtermans uses Patterson’s (1953) data and the lead isotopic
ratios of young terrestrial sediments, to compute a rough age for
the Earth of 4.5 ± 0.3 billion years. These represent the
first publication of the right value by a valid calculation.
However, Houtermans’ calculations are essentially isochrons based
on two data points (one data point for iron meteorites, another for
young terrestrial sediments). Without additional data to tie the
Earth and meteorites to a common source, the computed values are
not guaranteed to be meaningful.
|
| 1956 |
Clair C. Patterson publishes an isochron age for the solar system
(and therefore the Earth) of 4.55 ± 0.07 billion years. The
age computation is based on Pb isotope analysis of five meteorites.
Patterson points out that data for young Earth sediments fall on the
same isochron; this implies that the Earth shares a common origin
with the dated meteorites. Though only a few meteorites had been
dated at this point in time, and the individual meteorite ages that
did exist were not very precise, they also agree with the isochron
age.
|
| 1998 |
A lot of data has been collected since Patterson’s (1953, 1956) and
Houtermans’ (1953b) works. Precision of instruments has improved.
Many more meteorites have been sampled and dated. Moon rocks have
been sampled and dated. Decay constants have been measured with more
accuracy. New techniques have been devised, tested, and applied.
The arrival of this new data has two effects: (1) some new data
can be used to improve the precision of the original computations;
and (2) new independent measurements confirm the original ones.
Purely by coincidence, all of the adjustments (for example, current
values of decay constants) to Patterson’s 1956 computation have
canceled each other out. Today’s best estimate of the age of
meteorites (4.55 ± 0.02 billion years) is identical to
Patterson’s value except for the smaller error range. That value
has been confirmed dozens of times over.
The best estimate of the age of the Earth today is the same as that
for meteorites: 4.55 ± 0.02 billion years. In the event that
one wishes to be extra cautious in reporting a value, using the very
generous error range of 4.5 ± 0.1 billion years is almost
certain to encompass future changes as well.
For further detail on this topic, I strongly recommend G. Brent
Dalrymple’s The Age of the Earth.
|
References
Most of the references and quotations in the Chronology have been been
taken from the Catastrophism by Richard Huggett. This work is a
synoptic view of changing perspectives both of change in the inorganic
and organic world. Dalrymple’s Age of the Earth is a standard
source for understanding how the age of the Earth is determined.
Russell, H.N., 1921. A superior limit to the age of the
Earth’s crust in Proceedings of the Royal Society of
London, series A, vol. 99, pp. 84-86.
Dalrymple, G. Brent, 1991. The Age of the Earth.
California: Stanford University Press, ISBN 0-8047-1569-6.
Richard Huggett, Catastrophism, 1997, Verso, ISBN 1-85984-129-5.
Hugh Miller, The Testimony of the Rocks, 1857, Gould and Lincoln: Boston
Patterson, C.C., 1953. “The isotopic composition of
meteoritic, basaltic and oceanic leads, and the age of
the Earth” in Proceedings of the Conference on Nuclear
Processes in Geologic Settings, Williams Bay, Wisconsin,
September 21-23, 1953. pp. 36-40.
Patterson, Clair C., 1997. Duck Soup and Lead in
Engineering & Science (Caltech Alumni Magazine)
volume LX, number 1, pp. 21-31.
Russell, H.N., 1921. A superior limit to the age of the
Earth’s crust in Proceedings of the Royal Society of
London, series A, vol. 99, pp. 84-86.
Web Sites
Radiometric Dating:
A Christian Perspective contains an excellent summary of the common
readiometric dating methods.
The talk.origins archive
has a wealth of material about creationism and evolution; there are
some good pages on dating methods, geology, and the history of the Earth.
In particular the page on
dating
has an excellent summary of how modern geologic dating is done.`
The arguments of the 19th century creationist
Hugh Miller
against the Noachian flood are also at this site.
Acknowledgements
I particularly want to thank Mark Isaak who supplied a number of references
which were not available to me, Chris Stassen for supplying the section on
the history of radiometric dating, and Andrew MacRae who
supplied information about Hugh Miller’s The Testimony of the Rocks
I also wish to thank Jesse Weinstein for pointing out missing text.
This page was last updated December 11, 2010.
Typos were corrected February 16, 2005
Typos were corrected December 11, 2010
Copyright © 1998,2005, 2010 by Richard Harter