Figure 1.1
Clovis People, Ceremonial Spear Points, c. 10-8,000 BCE.
Found in Central Washington near East Wenatchee.
Translucent chalcedony, approximately 9½ inch long.
Drawing by Francisco Franco.
1
Chapter 1
ART AND TIME:
DATING METHODS, GEOLOGICAL
AND EVOLUTIONARY CONSIDERATIONS
The Telling of Time
techniques,4 are contributing to an ever greater
understanding of our remote past.
Dating sites, fossils and artifacts by multiple
methods produces much more accurate and reliable
results, as the various methods are usually best suited
for specific types of materials and conditions. The
chart below (figure 1.2) compares the various dating
methods by date range, application and limitations.
Many more methods for dating specimens are available
to modern researchers than can be discussed in this
book. The following glossary-style presentation is
limited to some of the most commonly used techniques
with their specific applications, useful age ranges and
degree of accuracy indicated where possible.
Typological sequencing is a relative dating
method based on the study of the formal characteristics
of artifacts. The method is based on the principles that
“products of a given period and place have a
recognizable style: through their distinctive shape and
decoration they are in some sense characteristic of the
society that produced them,”5 that the changes in style
are gradual, or evolutionary, and that they progress
from simpler to more complex form over time. Points
worth noting are that not all types of artifacts evolve at
the same rate and, as cultures decay, it is also often the
same case with the quality of their craftsmanship. This
A major problem in creating a workable
chronology for prehistoric periods has in the past, been
in finding ways to accurately date geological strata,
fossils and artifacts. Since the middle of the 20th
century, and particularly in the past two decades,
numerous scientific methods have been developed and
refined that have contributed tremendously to the
resolution of this problem. The clock that is now used
to measure geological time is based on radioactivity,
and dating by this method is called radiometry, or
radiometric dating. These methods produce absolute
dates and have allowed for the development of a
relatively accurate chronology of geological and
biological time. Aside from developing a calibration
technique for the well known radiocarbon dating
method used on organic materials,1 techniques have
been developed that allow the dating of such materials
as rock, tooth enamel, terra-cotta (baked clay), and even
to identify and date genetic material (DNA) of various
plants and animals.2
These new developments,
combined with the discovery of numerous fossil
specimens, remote sensing3 and computer imaging
1.
Alan Watchman, “Perspectives and potential for absolute
dating prehistoric rock painting,” Antiquity, vol. 67, no.
254, March, 1993, pp. 59-65: discusses the problems and
potentials for dating paint ‘vehicles’ such as human and
2.
animal blood and fat, bees-wax, egg white (casein), as
Sensing and Archaeology, held in 1984 at the National
well as charcoal and organic matter found in silica skins
Space Technology Laboratory (Now the Stennis Space
that build up on rock paintings.
Center) in Mississippi. The findings were published in a
Among these methods are Electron Spin Resonance,
1985 NASA volume, Remote Sensing and Archaeology:
Fission Track, Uranium Series, Thermoluminescence and
Potential for the Future. An example of the application of
Archaeomagnetic dating.
A concise but wide ranging
thermal infrared multispectral scanning was in its use for
analysis of dating techniques is presented in Colin
the discovery and mapping of nearly 1000 miles of
Renfrew & Paul Bahn, Archaeology, Theories, Methods
prehistoric roadways in Chaco Canyon, New Mexico (see
and Practice, London and New York, second edition,
John
1996, pp. 111-64; and in Jane McIntosh, The Practical
Archaeology, January/February, 1994, pp. 37-41.)
4.
Archaeologist, How we know what we know about the
Mary
“Spirit
Rose,
Paths
“Pleistocene
of
the
Computer
Anasazi,”
Heads”
A more
(Newsbrief), Archaeology, November/December, 1994, p.
in-depth view of these methods is covered in M. J. Aitken,
16, for the reconstruction of a 400,000 year old archaic
Science-based Dating in Archaeology, London & New
Homo sapiens skull based on fragments from two skulls of
past, New York & Oxford, 1988, pp. 130-145.
different sizes.
York, 1990.
3.
See
Wicklein,
J. Wiseman, “Space Missions and Ground Truth,”
5.
C. Renfrew and P. Bahn, 1996, pp. 114-16, discusses the
Archaeology, July/August, 1996, pp. 11-13. This type of
methodology and provides a diagram. The related method
research came out of the first Conference on Remote
of seriation is covered on pp. 116-18.
2
methodology is particularly useful in dating
technologies from the upper Paleolithic through the
Bronze Age, where there is little if any documentary
evidence.
It can also be applied to more modern
periods as well.
Figure 1.2 Comparison of Dating Techniques.
Graph by the Author.
based on the “overlapping of the ring patterns of
successively older timbers to build a master sequence or
chronology and the subsequent dating of wood samples
by comparison of their individual patterns with the
established chronology.”7 Dendrochronology allows
for determining dates precise to within a year. The
bristle cone pine chronology from the White Mountains
of California is the most accurate tree ring sequence,
and is at present reliable back to about 6200 BCE.
Bristle cone trees can live over 4000 years, and both
live and dead trees are used in developing the
chronologies.
Dead bristle cone pines survive for
thousands of years in situ because of their low decay
rate caused by their high resin content and their dry
environment. Because the trees are organic, the
individual rings within them can be subjected to the
Stratigraphy is a relative dating method based
on the study of stratification (layering of soil and
rocks), and is applicable to land deposits, as well as to
rubbish piles and fire pits.6 The methodology is based
on the chronology of deposits, and is dependent on the
principle of the underlying layers being deposited
before the upper layers. Within each layer are organic
materials that can be subjected to absolute dating
methods such as calibrated radiocarbon (see below), as
well as man made artifacts that can be assigned
independent chronologies based on typological
sequencing. Together these various methods, when
considered in relation to each other, can produce
revealing pictures of otherwise mute evidence.
Dendrochronology (tree ring dating) is based
on the fact that each year a tree ring is added to the
outer edge, the cambium layer (just below the bark) of
tree trunks, providing a truly known-age material.
Systematic dendrochronological studies were begun
by A. E. Douglass at the beginning of the twentieth
century and were applied to archaeological problems by
the early 1920s. The methodology is simple and is
7.
See M. G. L. Baillie, Tree-Ring Dating and Archaeology,
Chicago, 1982, for a concise history of its development as
well as clear explanations of its methodology, its
relationship to the radiocarbon dating method, and the
6.
The method and theory of stratigraphy was born with the
application of dendrochronology to archaeology. Also see
publication of William Smith, Strata Identified by
M. G. L. Baillie, A slice through time: dendrochronology
Organized Fossils, 1815.
and precision dating, London, 1995.
3
radiocarbon (14C) dating method and utilized as a
calibration technique for the latter.
Willard Libby (awarded the Nobel prize for
chemistry in 1960) and Ernest Anderson at the
University of Chicago developed the radiocarbon
(14C)8 method in the late 1940s. The method is based
on the radioactive decay (half-life of 5730 years) of
14C in organic matter such as bone, wood and seeds.
This method is effective for accurately dating samples
from about 40,000 to less than 200 years before present
(BP). In the 1950s the results were found to have
systematic discrepancies with historical records dating
back to c. 3100 BCE by as much as 600 years. It was
recognized that these discrepancies were caused by
such factors as variations in atmospheric 14C
concentrations, cosmic radiation, nuclear fall-out, and
various other “alteration effects”.
Numerous
techniques,
particularly
dendrochronological
calibration, have since been developed that allow for
much more accurate results. The introduction in the late
1970s of accelerator mass spectrometry (AMS),
which is based on the variance of deflection of moving
charged particles of different mass by magnetic fields,
has greatly refined the accuracy of 14C dating and
extended the methods usefulness from 50,000 to about
80,000 years. 14C results are generally accurate to ± 80
to 100 years of the sample’s true age, but contamination
can lead to serious errors.
The Thermoluminescence (TL) method is
based on the amount of trapped electrons in a
crystalline specimen and is applicable to such materials
as ceramics and burnt flints, and has also been applied
to calcium carbonate deposits in caves.9 The electron
traps in clay and flint are completely emptied when
they are subjected to heat above 932° F, such as when
terracotta is fired (baked), or a flint core is tempered
before tools are produced from it.10 After the specimen
has cooled it again becomes a radioactive clock by its
absorption of energy that can then be read when a
sample is reheated. The advantages of TL dating is that
it is applicable to inorganic materials and is useful for
obtaining dates beyond the 50,000 year lower limit of
the 14C method, with useful results to about 90,000
years ago. The method is not as accurate as 14C, and
rarely provides precision better than ± 10 % of the
8.
sample’s true age, but is extremely useful in developing
chronologies and in the identification of forgeries
produced within the last 100 years.
Closely related to TL is the Optically
Stimulated Luminescence (OSL) method, which
measures the luminescence of minerals caused by light
rather than heat. Sunlight bleaches (purges) the
electron traps in quartz grains (sand), which begin
trapping electrons once they are buried as part of
sediment. The method is accurate to ± 10 % of the
sample’s true age. One of the best case studies for OSL
has been in obtaining a dating of c. 1400-600 BCE for
the White Horse of Uffington, a 300-foot-long figure of
a horse carved into the chalk hillside at Uffington,
England, making it some 1000 years older than
previously believed.11
The potassium-argon (K-Ar) method is used
by geologists to date rocks and is dependent on the
radioactive decay rate (1.3 billion year half-life) of
potassium to argon in volcanic specimens. The slow
decay rate of potassium gives the method one of the
deepest ranges, being useful in dating the oldest rocks
(billions of years old) and has a upper limit of about
100,000 BP.12 Its usefulness is found in determining or
cross checking the relative age of archaeological
remains buried below the residue of volcanic activity,
either lava or ash, by providing dates for the residue.
The margin of error is rarely better than ± 10 % of the
sample’s true age.
The Electron Spin Resonance (ESR) method
is used for dating tooth enamel of both human and
animal specimens. Tooth enamel is composed almost
entirely of the mineral hydroxyapatite, which contains
no trapped electrons when it is newly formed, but
which begins to trap electron once it is buried. ESR
requires the destruction of a sample, is temperature
sensitive, and has a margin of error between 10% and
20% of the sample’s true age.
Despite these
drawbacks, the method has been useful in providing
and confirming dates ranging from 120,000 to 60,000
BP.
In summation, these techniques and numerous
others, when used to determine dates through blind
sampling, and employed in conjunction with other
techniques as crosschecks, are extremely useful in
building evidence and chronologies for individual
specimens and for whole groups of related material.
For instance, the dating of a hypothetical campsite can
be more accurately determined if it has significant
depth such that it can be subjected to stratigraphic
analysis, in which a relative sequence of habitation can
be determined. Samples of charcoal and other organic
materials from this site can be subjected to 14C tests
from several distinct strata and an even greater relative
approximate dating can be determined. If terracotta
samples are discovered and are subjected to TL tests
and the dates relate to those of the 14C test dates, an
C. Renfrew and P. Bahn, 1996, pp. 131-38, discusses the
methodology and provides useful diagrams and a clear
explanation of ‘The Principles of Radioactive Decay’.
See Sheridan Bowman, Interpreting the past, Radiocarbon
Dating, Berkeley, 1990, for a more in-depth introductory
examination of the basic principles, calibration techniques
(dendrochronology), and its application to archaeology.
9.
C. Renfrew and P. Bahn, 1996, pp. 144-47, discusses the
10.
C. Renfrew & P. Bahn, 1996, p. 306, discusses the tool
methodology and provides diagrams.
working methods and notes that such heat treatments of
flint was already present by about 19,000 years ago in
11.
See (Newsbriefs), Archaeology, July/August, 1995, p. 24.
France, and that TL dating can be used for determining
12.
C. Renfrew and P. Bahn, 1996, pp. 139-40, discusses the
methodology and provides examples of usefulness.
the temperatures to which the specimens were subjected.
4
material loose, which eventually coalesced to form the
moon. In these past four billion years Earth has
undergone tremendous changes that are stratigraphically recorded in its stone, sea floors and polar
ice caps. Over a billion years after the Earth formed it
began to cool. Life began as bacteria and algae over
3½ billion years ago and a biosphere developed, which
in time spawned tremendously varied groups of life
forms.15 Numerous mass extinctions and speciations
have occurred throughout the record; the exact causes
and patterns of which are known only in part.16 The
most devastating of these extinctions occurred 251
million years ago at the end of the Permian period,
probably caused by a meteorite impact, wiped out about
80% of all life on the planet and gave rise to the
environment that led to the evolution of the dinosaurs.17
Some 200 million years ago (MYA) there was a
single landmass on the earth which scientists call
Pangaea (“all lands”), and a universal ocean called
Panthalassa (“all seas”). Since then Pangaea has
broken into a score of pieces, some of which have
even more reliable picture begins to emerge. These
dates can be corroborated independently if a layer of
quartz sand is discovered and can be subjected to OSL
tests. Finally, if a document, such as Sumerian clay
tablet that includes a specific historical date, is
discovered at the site, and the date matches those of the
approximate radiometric dates determined from the
tests, and absolute date can be determined for the site.
A Very Brief History of the Earth
The combined evidence of a wide range of
sciences has contributed to the development of a broad,
interwoven and consistent picture of a cosmic, geologic
and biologic evolutionary development.13 The specific
age (about 14 billion years old) and essential character
of the universe is unknown, but significant progress
was made in the 20th century towards understanding
it.14
Science tells us that the Earth is at least 4½
billion years old, but probably not much more than 5
billion years old. Within a billion years of Earth’s
creation it was struck by a large asteroid, which tore the
15.
Life has developed in or colonized such diverse and
unlikely environments as thermal springs, the ocean floor,
and even up to 1.7 miles below the surface of the earth.
13.
14.
An excellent overview of the evidence for evolution is
For the recently discovered microbe “archaea” that
presented in K. C. Allen and D. E. G. Briggs, Evolution
constitute a third form of life on Earth see David Perlman,
and the Fossil Record, Washington D. C., 1989. This
“Microbe Confirmed as New Form of Life,” San
Smithsonian volume includes contributions by eleven
Francisco Chronicle, August 23, 1996. For the organisms
specialists, addressing such topics as “Evolution of the
dwelling
Universe, stars and planets,” and “Patterns of evolution
Frederickson & Tullis C. Onstott, “Microbes Deep inside
and extinction in vertebrates,” but does not address the
the Earth,” Scientific American, vol. 275, no. 4, October
evolution of man.
1996, pp. 68-73.
A more recent and well illustrated
within
the
earth’s
crust
see
James
K.
An extensive examination of the
treatment of the evolution of life is Stephen Jay Gould
evolution of life on Earth is presented in Reter J. Bowler,
(general editor), The Book of Life, 2001 (1993), with a
Life’s Splendid Drama:
new introduction containing more recent information.
Reconstruction of Life’s Ancestry, University of Chicago
An excellent popular view of astronomy is Carl Sagan,
Press, 1996, reviewed by Kevin Padinm “Evolution’s
Evolutionary Biology and the
Cosmos, New York, 1980. For a concise but illuminating
Evolution,” Nature, vol. 385, no. 6612, January 1997, pp.
discussion on the nature of the universe, its age, and the
127-28.
16.
problems scientists confront in examining it, see Stephen
See Michael J. Benton, “Patterns of evolution and
Hawking, The Illustrated A Brief History of Time (updated
extinction in vertebrates,” in K. C. Allen and D. E. G.
and expanded edition), New York, 1996. The nature of
Briggs, Evolution and the Fossil Record, Washington D.
the universe, its evolution, and the impact of quantum
C., 1989, pp. 218-41. This study gives an overview of the
theory are covered in Stephen W. Hawking and Roger
mass extinction phenomenon, and covers methodology,
Penrose, “The Nature of Space and Time,” Scientific
incompleteness of the record, and the problems with the
American, vol. 275, no. 1, July, 1996, pp. 60-65. For
26 million year extinction periodicity pattern proposed by
Alexander Vilenkin’s idea of our universe being only one
Raup and Sepkoski (1984; 1986). “The history of fishes
of many, see David H. Freedman, “The Mediocre
and tetrapods [land animals] has been punctuated with at
Universe,” Discover, vol. 17, no. 2, February, 1996, pp.
least eight and six mass extinction events respectively.
65-75. For a general look at the development of science
Some of these overlap with each other, and with extinction
events reported for other groups of organisms” (p. 233).
and technology in the 20th century see Trevor I. Williams,
17.
Science, a History of Discovery in the Twentieth Century,
See Douglas H. Erwin, “The Mother of Mass Extinctions,”
Oxford, 1990. This book includes numerous short reports
Scientific American, vol. 275, no. 1, July, 1996, pp. 72-78.
on a broad range of topics;
of which the reports on
It is estimated that less than 1 % of all types of life forms
continental drift (pp. 50-51), plate tectonics (pp. 190-91),
that have ever existed on Earth are currently present in our
relativity and quantum physics (pp. 52-53 and 79-87), and
biosphere, but it appears that the total mass of life forms
the structure of DNA (pp. 141-47) are of interest for the
remains relatively constant during periods of non-
present study.
cataclysmic activity.
5
Stegosaurus and Allosaurus developed during the
Jurassic Period, but it was during the Cretaceous
Period, with the evolution of such well known types as
Veloceraptor, Triceratops and Tyrannosaurus Rex, that
they reigned supreme. Another interesting development of the Cretaceous Period was the evolution of
birds, which appear to be directly related to
dinosaurs.20 For some still unknown reason, possibly a
large asteroid impact21 or extensive volcanic activity,
dinosaurs became completely extinct at the end of the
Cretaceous Period (65 MYA).22 Flowering plants, birds,
and most importantly, mammals, which had all evolved
before the demise of the dinosaurs, began their
domination of the terrestrial biosphere following the
beginning of the Tertiary Era (65 MYA).
An interesting side note on the probable
influence of dinosaur fossils on ancient arts,
demonstrated by Adrienne Mayor, is the relationship of
the shape of the beak shaped Protoceratops skull to that
of the mythical griffin of Central Asia. Mayor notes
that it is highly probable that:
formed the continents and divided Panthalassa into the
present configuration of oceans and seas. The study of
this phenomenon is called plate tectonics:
the
mechanism responsible for continental drift, the
building up of mountains and the primary cause of
volcanic activity and earthquakes.18
Because limestone and marble19 are so highly
valued for the production of architecture and sculpture,
it is useful here to note the evolution of these materials.
Limestone is a sedimentary rock consisting mainly of
calcium carbonate, which is formed at the bottom of
seas from the skeletal remains of marine
microorganisms and coral. Marble is metamorphosed
limestone whose structure has been re-crystallized by
heat and pressure. In certain areas the forces of plate
tectonics has pushed large deposits of marble up to
form mountain ranges. This process of converting once
living matter into a crystalline form takes millions of
years.
Dinosaurs ruled the land during the Mesozoic
Era, which lasted from about 245 to 65 MYA. Such
immense creatures as the Brontosaurus (Apatosaurus),
18.
“…ancient nomads could have
observed fully articulated remains of
An excellent survey of the history and principles of plate
tectonics is Walter Sullivan, Continents in Motion, New
20.
York, 1991. The first to develop a theory of continental
provides the most graphic evidence yet that birds are
on the subject to the Frankfurt Geological Association.
descended from them (Photographs of the fossil were
Prior to the development of this theory in the 1960s, the
shown on 17 October, 1996, at the American Museum of
scientific community generally embraced catastrophic or
Natural History during the annual meeting of the Society
flood
physical
of Vertebrate Paleontology). Discovered in China, this
characteristics of the Earth. “It is also due largely to the
specimen is the first creature of any type, other than birds,
geology
theories
to
explain
the
that had feathers.
contributions of [W. Jason] Morgan [of Princeton] and
21.
Dan McKenzie of Cambridge University that the concept
See ‘Postscript’ to Chapter 6 for a discussion of impacts
and for bibliography.
of the Earth as being paved with a spherical mosaic of
22.
moving plates has come to be known as “plate tectonics” -
19.
The fossil of a new dinosaur, dated to c. 121 MYA,
drift was Alfred Wegener, who, in 1912, presented a paper
Michael J. Benton, 1989, p. 237 notes: “The Cretaceous-
a term that today symbolizes the revolution in our
Tertiary boundary (K-T) event is surely the best known
understanding of the Earth (W. Sullivan, 1991, p. 243).
mass extinction... However, in terms of the relative loss of
Geophysicist John Baumgardner of Los Alamos National
families, this event was smaller than all of those [seven]
Laboratory in New Mexico “has created a computer model
that preceded it.” An excellent overview of this problem
that appears to answer one of the fundamental questions of
is presented in Kenneth J. Hsü, The Great Dying, Cosmic
plate tectonics: what forces caused Pangaea, the Earth’s
Catastrophe, Dinosaurs, and the Theory of Evolution,
original supercontinent, to break up into today’s
Orlando, Florida, 1986. For the most up to date discussion
continents.”
This was reported by Johnathan Beard,
on the subject, including evidence of other factors, see J.
“How a supercontinent went to pieces,” New Science, No.
David Archibald, Dinosaur Extinction and the End of an
1856, January 16, 1993, p. 19.
Tom Yulsman, “The
Era, What the Fossils Say, New York, 1996; and Gerrit L.
Seafloor Laid Bare,” Earth, vol. 5, no. 3, June, 1996, pp.
Verschuur, Impact, The Threat of Comets and Asteroids,
42-51, illustrates and discusses the creation of the first
New York & Oxford, 1996. For dinosaur fossils see Mark
complete map of the sea floor. This false-color image is
A. Norell, Eugenene S. Gaffney & Lowell Dingus,
based on gravitational fields and was produced by the U.
Discovering Dinosaurs in the American Museum of
S. Navy in eighteen months (beginning in 1985) using a
Natural History, New York, 1995. For a concise overview
Geosat satellite (See: Exploring the Ocean Basins With
and excellent reconstruction illustrations of prehistoric
Satellite
animal life see Douglas Dixon et. al., The Macmillan
Altimeter
Data,http://www.
ndgc.noaa.gov/mgg/announcements/
Illustrated Encyclopedia of Dinosaurs and Prehistoric
images_predict.html.).
Animals, A Who’s Who of Prehistoric Life, New York,
For a geological discussion on these stones see Steven M.
1988; and Sylvia J. Czerkas and Stephen A. Czerkas,
Stanley, Exploring Earth and Life through Time, New
Dinosaurs, A Global View, Barnes & Noble, revised
York, 1993, p. 489-91.
edition, 1996.
6
again, and the sea level dropped an estimated 70
meters.
The greatest glaciations occurred about 18,000
years ago with much of northern Eurasia and North
America covered with ice sheets up to 2 miles thick.
The global climate at this time in winter was 11ºF
colder than present, but is known to have dropped to
about 24ºF colder for periods of 200 and 500 years
each. In Europe the temperature reached as low as 22ºF in winter and in the summer rarely exceeded
64ºF. These colder temperatures caused wind speeds
to increase by a factor of two compared to the
present.24 The freezing of the waters during this
period, and the depositing of it at the poles and on the
northern land masses, lowered the sea level by as much
as 120 meters (figure 1.4). From about 82,000 years
ago glacial conditions generally prevailed as listed
below and in figure 1.3:
dinosaurs about the size of wolves
and resembling large flightless fourlegged raptors, “guarding” the
approaches to Issedonian gold
deposits. To ancient observers, such
finds plus knowledge of animal
behavior may have suggested scenes
of fierce animals defending territory
and young…”23
Examples of such fierce attacks are vividly
depicted on the solid gold Pectoral found in a 4th
century BCE Scythian chief’s tomb in the Caucasus
Mountains. Images and reports of this “fantastic”
animal made their way into Greece where the subject
became very popular. Similarly, the origins for the
myth of the Cyclops, the giant one-eyed humans that
terrorized the ancient Greeks, has been suggested to
have derived from a misunderstanding of the features of
mammoth skulls.
Returning to the geological conditions; for
some unknown reason, and after a lengthy warm period,
the planet began cooling about 38 million years ago
(Oligocene period). The world had seen the division of
the landmass into its present configuration; having
broken up from a single land mass called Pangaea.
During the Miocene Period (25-10 MYA) grazing
mammals, and the mammalian carnivores that hunted
them, became widespread and dominated the terrestrial
aspect of the biosphere. The early Miocene saw the
development of the primate (monkeys) line from which
man would evolve (see below). It was during this
period that the great mammals flourished, evolving into
a myriad of such strange creatures as the shovel-tusked
amebelodon (related to the elephant), giant camels and
the 33-ton indrocotherium (related to the rhinoceros), as
well as a great variety of whales.
The Ice Age (Pleistocene) began about 2.5
MYA and lasted until about 11,000 years ago (figure
1.3). A sudden drop in temperature brought on the first
extended global cold spell, called the Donau, which
lasted about 750,000 years, and caused ice sheets to
begin building up on the northern continents. It could
very well be that the development of the distinctly
human line, beginning with Homo habilis in Africa,
was a direct effect of this climate change. Interstadials
(warming periods) punctuated the Ice Age, but the
climate appears to have remained milder than present
day temperatures. At the beginning of the Eemian
interglacial period (127-117,000 years ago) the sea
level was 6 meters higher than at present. Suddenly,
about 115,000 years ago, ice sheets began forming
cold
warm
cold
warm
cold
warm
82-62,000 years ago
62-54,000 years ago
54-39,000 years ago
39-35,000 years ago
35-11,000 years ago
11,000 years ago to the present.
The lowering of the sea level, in turn, exposed
great areas of the continental shelf, especially in
Southeast Asia and the Bering Strait, forming the land
bridge between the old and new worlds. Other land
bridges were made across the Straits of Gibraltar and
the English Channel, while the numerous islands of
Indonesia and the Philippines formed a single great
landmass, and New Guinea and Australia were
connected by land under what is now the Gulf of
Carpentaria. The Sea of Japan was landlocked, while
the Persian Gulf, the Adriatic Sea and the Gulf of
Tonkin were lush river valleys. During this period man
shared the lands with numerous large herbivores, such
as the mammoth, mastodon, woolly rhinoceros, bison,
ground sloth, giant camel, horse and a wide variety of
deer. Man and such carnivores as the saber toothed
tiger, the giant lion, and the dire wolf, also hunted these
animals.25
24.
C. Renfrew and P. Bahn, 1996, pp. 211-252, discusses
environmental
archaeology.
Evidence
for
the
temperatures is derived from thousands of deep-sea core
samples from the Pacific Ocean and glacial core samples
taken from Greenland and the Antarctic.
One Pacific
ocean floor core sample is 69 ft. long and contains the
23.
Adrienne Mayor, “Guardians of the Gold, A twentieth-
climate record for the past 2 million years, while the 1.9
century scholar tracks the origin of the legendary griffin
mile long Greenland ice core has at least 200,000 “annual
from seventh-century Greece back to the Age of the
growth layers” (p. 212).
25.
Dinosaurs,” Archaeology, November/December, 1994, pp.
R. J. G. Savage & M. R. Long, Mammal Evolution: An
53-58; and p. 59, for “Flights of Imagination” by the same
Illustrated Guide, New York & Oxford, 1986, provides a
author which describes the history of the problem and
clear picture of the evolution processes and range of
interpretation of the imagery.
mammals forms that developed.
7
Figure 1.3
Climate variations during the past 10 million years
(Graph by the Author)
continental shelves, massive changes in the forestation
of the remaining lands, the emergence of great desert
areas, and the mass extinction of large mammals
(mammoth, mastodon, woolly rhinoceros, sloth, giant
camel, saber toothed tiger, giant lion, dire wolf, and
many more) as well as many types of birds, fish and
plants. The spear of modern man has also been linked
to the extinction of the mega fauna through over
hunting and the upsetting of the environment.26 If this
supposition bears out, then man’s developing
technology has been a constant drain on the biosphere
for a very long time.
About 11,000 years ago, and after more than
70,000 years of extremely cold conditions, and for
some reason yet unknown, the ice age came to a violent
and spectacular end in an event of apocalyptic scale.
The total duration of this cataclysmic episode was only
about 250 years, during which time tremendous
proportions of the massive reservoir of water held in the
glacial ice sheets melted. The mean temperature of
Greenland increased by 13° F in a single 50-year
period. The build up of heat and the melting of the ice
sheets produced torrential rains and winds that may
have lasted months at a time, causing unimaginable
floods and devastation. The impact on the biosphere
resulting from these floods and the rise in global
temperature was tremendous, causing the permanent
inundation of extensive tracts of land along the
26.
Peter D. Ward, The Call of Distant Mammoths: Why the
Ice Age Mammals Disappeared, New York, 1997.
8
Figure 1.4
Sea levels and glaciations limit at c. 18,000 years ago and at present
map by the author
The net transformation of the environment was on a
scale unlike anything humanity had ever witnessed and
must certainly have had a climacteric affect on the
human psyche. The cause of this change in climate is
not known, but there is growing evidence that it may
have been the result of asteroid impacts.27 The warm
period following this episode has continued to the
present, and is called the Holocene (Holo [complete]
27.
cene [new, recent]). It was at the beginning of this
period that man began domesticating plants and
animals, and developed permanent settlements that led
to complex societies.
Human Evolution:
A History of Scientific Discovery
The branch of science dealing with the life of
past hominid periods, as known from fossil remains, is
called paleoanthropology, and a person involved in the
search for fossils is called a paleontologist. Among the
most important researchers to contribute to our
scientific understanding of human origins are
evolutionist Charles Darwin, anatomist Raymond Dart,
physician Robert Broom, paleoanthropologists Louis
and Mary Leaky and their son Richard, Donald
Johanson, Tim White, and biochemists Allen Wilson
and Vincent Sarich.
Since
the
publication
of
Darwin’s
revolutionary Origins of Species by Means of Natural
Selection, or the Preservation of Favored Races in the
Gerrit L. Verschuur, Impact, The Threat of Comets and
Asteroids, New York & Oxford, 1996, discusses the
intriguing hypothesis of Edyth Tollmann & Alexander
Tollmann, De Londuloed: Van mythe tot historische
werklijkheid, Baarn, 1994, that, based on mythological
interpretations, places the great flood at 9500 years ago
with asteroid impacts as its cause. An example of such
impacts is the 1500 foot wide and 650 foot deep Berringer
meteor crater in Arizona that occurred 49,000 years ago.
Some 1500 other craters have been detected around the
world.
As seventy percent of the Earth’s surface is
covered by water, the probability is that an equal
percentage of asteroids have impacted there.
9
Struggle for Life in 1859 and The Descent of Man and
Selection in Relation to Sex in 1871,28 a tremendous
body of fossils, cultural remains, and related research
has been used to reconstruct the basic line of human
evolution.
Though many hominid fossil remains,
reaching back millions of years, have been discovered
and placed within a basic chronology, it has not been
demonstrated conclusively that any particular specimen
belongs to the evolutionary line leading directly to man.
What has been demonstrated from the fossil specimens
is that more complex structured, larger-brained
specimens are never found in lower strata than
specimens of simpler structured skeletons with smallerbrain cavities. In general, it can be stated from a
scientific point of view that the overall evolutionary
picture and chronology is incontrovertible, and that
current discussion centers on the specific relationship of
the various species that inhabited the same time frame
and/or geographic location.29
The evidence of the fossil specimens was
given further support in 1967 by molecular evidence
presented by Allen Wilson and Vincent Sarich,
molecular biologists at the University of California at
Berkeley, who demonstrated that the genetic material
(mitochondrial DNA-deoxyribonucleic acid)30 of man
28.
and chimpanzee are 99% identical, and that the primate
(chimpanzee, etc.) and hominid (human) evolutionary
lines diverged perhaps 6 to 5 MYA, when an
unprecedented chill swept across the African
continent.31 Prior to this discovery evolutionary theory
accepted that the ape/man line diverged some 30 to 15
MYA. These genetic studies further led Wilson and his
colleagues to conclude that: “the common ancestor [the
so-called ‘Eve’], of modern humans lived in Africa,
about 200,000 years ago” and that “when individuals
from this population moved out of Africa into Europe
and Asia, they did so with little or no mixing with the
local population of more primitive humans.”
Biochemist Roger Lewen points out that when this new
population migrated from Africa to Europe and Asia
“their skin probably would have been black. And the
skin of the archaic populations they encounteredincluding Neanderthals-in these new lands would have
been white. Over time, Homo Sapiens Sapiens would
have become paler, an evolutionary adaptation to the
decrease in the intensity of the sun found in higher
latitudes.” and that by about 15,000 years ago “all
European populations would have been white.”32
Without going into the complex discussion of
the evolution of now extinct earlier hominid types,
because they are only tangentially related to the
problem of the nature of art, we can proceed with a
brief account of the anatomically modern man: Homo
sapiens sapiens, the double knowing man [he who
knows what he knows].33 This subspecies is less
powerfully built than Neanderthal (that does not appear
to have been directly related to modern man34) and has
a cranial capacity between 1500 and 1800 cc. The
earliest datable fossils (c. 125,000 years old) of modern
man have been found at Klasies River Mouth in South
Africa, and appear to have spread from that general area
throughout the world. Archaeologist Alison Brooks
An excellent and concise account of the discovery of
natural selection is presented in Daniel J. Boorstin, The
Discoverers, New York, 1983. Part twelve (“Cataloguing
the Whole Creation”, pp. 420-76) of this book discusses
the European intellectual developments on the problem
from the Renaissance to the nineteenth century research of
Darwin and Wallace (pp. 464-76).
29.
For a concise and clear discussion of human evolution,
with
copious
illustrations,
graphs,
reconstructions,
historical backgrounds on the discoveries, and an
evaluation of the arts and technologies of early man, see
Roger Lewin, In the Age of Mankind, A Smithsonian Book
of Human Evolution, Washington D. C., 1988; and Ian
Earth, vol. 5, no. 1, February, 1996, pp. 27-35. Another
Tattersall, The Human Odyssey, Four Million Years of
major development that challenges our sense of reality is
Human Evolution, New York, 1993. The major drawback
the cloning of large mammals in 1996 which was
announced in early 1997.
to these introductory volumes is their lack of bibliographic
31.
sources for specific topics. An excellent CDROM on the
30.
Allen Wilson and Vincent Sarich, Science, vol. 158, 1
topic is Origins of Mankind, Maris Multimedia, 1996.
December, 1967, pp. 1200-03. “The time divergence of
DNA samples taken from the placentas of 147 women of
man from the African apes is...five million years” ... “We
different racial backgrounds were compared. The research
suggest that the living apes and man descended from a
is based on the accumulation of random and regular
small member of the widespread Miocene dryopithecines,
changes to a species’ genetic material over millions of
which became uniquely successful due to the development
years (the molecular clock). The deduction was that all
of the locomotor-feeding adaptation known as brachiation
people are descended from a single "Eve" that lived in
[swinging by the arms from one hold to another]” (p.
Africa some 200,000 years ago. The methodology was
1202).
viciously attacked when it was first presented, but is now
32.
R. Lewin, 1988, pp. 144-45.
generally accepted, and has been applied to other studies
33.
For an introduction to the archaeology of modern man see
34.
Jean-Jaques Hublin, “Brothers or Cousins?”, Archaeology,
Ian Tattersall, 1993, pp. 133-52.
involving the origins and diffusion of the various races, as
in L. Luca Cavalli-Sforza, Paolo Menozzi & Alberto
Piazza, The history and geography of human genes,
Sept/Oct. 2000, pp. 49-54, using casts of inner ears
Princeton (NJ), 1994. The controversy surrounding this
demonstrated the subspieces hypothesis, which had earlier
theory is discussed in Ruth Flanagan, “Out of Africa,”
been demonstrated using DNA.
10
Most spectacularly, it was Cro-Magnon that
began producing the figurative arts, in both sculpture
and painting, which have survived in large quantities.
They buried their dead with adornments of shell, animal
teeth and stone, and often included tools and weapons
as well as offerings of food and herbs. It is probable
that they also developed body painting and other forms
of personal adornment, and created decorations on
utilitarian items such as animal skins, tool handles and
their dwellings. They lived in portable huts, usually
made of mammoth tusks, large bones, light branches
and skins, which were similar to those lived in by the
North American Indians. Other groups of people
however preferred the shelter of overhanging cliffs,
such as those at the Vezere River Valley, France.
and John Yellen claim that barbed bone points found at
Katanda in eastern Zaire, Africa, dating to c. 90,000
Before Common Era (BCE).35 These highly refined
tools predate similar examples found in Europe by
some 75,000 years, and support the suggestion that
modern human behavior (nuclear family units following
a subsistence pattern) had its origins in Africa. Modern
humans were living in various parts of Africa between
130,000 and 60,000 years ago, are dated in Israel by
about 90,000 years ago, and did not enter into Europe
until about 35,000 years ago. Recent discoveries at a
site in the tropical northwest of Australia suggest that
some form of humans inhabited that continent 115,000
years earlier than previously believed.36 This evidence
comes in the form of stone tools and other findings
dating to 176,000 years ago. Also discovered in this
location are engraved monoliths that may be 75,000
years old, and rock art that date between 50,000 and
75,000 years old.
The earliest specimens of modern man in
Europe were discovered at Cro-Magnon in the
Dordogne River Valley, France, and were named for
the location. The Upper Paleolithic (paleo [early] lithos
[stone]) period (c. 35,000-9,000 BCE) refers that which
includes the European Pleistocene hunters (CroMagnon man) and is characterized by the rough or
chipped stone implements they produced. The CroMagnon people traveled in groups of perhaps 50 - 75
members, wore tailored clothing of animal skins to
protect themselves from the glacial cold, and lived in
the mouths of caves, in rock shelters, and in portable
dwellings made of skins, bones, and branches. They
produced refined stone tools, spear throwers, and began
using glue37 and thread drawn with eyed needles to
bind objects. The Cro-Magnon people were skilled
hunter-gatherers who first developed big-game hunting
and true cooking between 45,000 and 35,000 years ago.
They followed the migrations of the reindeer in much
the same way that the North American Indian later
followed the bison, or the Laplanders follow the
caribou. Deer meat was their main source of protein
and they also hunted the woolly mammoth, wild cattle,
bison, and horse.
The Peopling of the Americas
The genetic evidence indicates that the earliest
groups of immigrants to enter the Americas were
natives of the Eurasian continent who were closely
related to the Asian race. Further evidence, including
mtDNA studies,38 indicates that they most probably
entered via the Bering Land Bridge (between the tips of
Asia and Alaska) caused by the lowering of the sea
level during the height of the Ice Age.39 It is not
known exactly when humans first entered the Americas.
There is no fossil undisputed evidence for a dating
before 14,000 years ago. This date coincides with a
retreat of the glacial ice that opened a dry corridor that
allowed passage through Alaska and Canada east of the
Rocky Mountains.
On the other hand, recent
radiocarbon dates for organic materials found in
association with stone tools in the Mojave Desert of
California point to at least some occupation by 26,000
years ago.40 If this earlier dating is correct, then the
38.
See Tabitha M. Powledge & Mark Rose, “The Great DNA
Hunt, Part II, Colonizing the Americas,” Archaeology,
November/December, 1996, pp. 58-68, for the genetic
(mitochondrial DNA) connection between the Paleoindian
35.
“Origins of Modern Human Behavior” (Newsbrief),
and Siberian populations, as well as evidence (p. 60) for a
Archaeology, November/December, 1995, p. 27.
separation “between 41,000 and 20,500 years ago.” A
The
three sites are at Katanda in the Simliki River Valley.
36.
migration about 30,000 years ago is further supported by
R. L. K. Fullagar, D. M. Price & L. M. Head, “Early
linguistic, dental and blood-type evidence (p. 62).
39.
human occupation of northern Australia: archaeology and
37.
A comprehensive examination of this problem is presented
thermoluminescence dating of Jinmium rock-shelter,
in Frederick Hadleigh West (ed.), American Beginning:
Northern
270,
The Prehistory and Paleoecology of Beringia, University
December, 1996, pp. 751-73. The site at Jinmium in the
of Chicago Press, 1996, reviewed by Paul G. Bahn,
Kimberly region was revealed to researchers by local
“Bridge to the past,” Nature, vol. 385, no. 6612, January
aborigines in 1992.
1997, pp. 128-29. For a concise discussion of the spread
Announced in “Field Notes,” Archaeology, July/August,
of humans across the globe see C. Renfrew and P. Bahn,
Territory,”
Antiquity,
vol.
70, no.
1996, p. 24: The discovery at Umm el-Tlel, Syria, of
1996, pp. 156-62, with detailed map.
40.
36,000 year old stone tools with bitumen (a petroleum
See Paul G. Bahn and George Oliver, “Rock Art Reports”
based adhesive) found on them demonstrates that
(Newsbriefs), Archaeology, November/December, 1994,
adhesives were used more that 26,000 years earlier than
p. 22. The significance of this report is that it presents
previously believed.
evidence for pushing back the generally accepted date for
11
Paleo-Indian may have first entered when a dry corridor
opened about 30,000 years ago. Whenever the entry
occurred, the genetic evidence indicates that it was by
only a few thousand people who probably followed
migrating herds of large game (probably caribou). This
small group of people multiplied and spread over the
entire continent and developed a wide range of life
styles. They have been identified by their characteristic
spear points, which have been discovered throughout
North and Central America. They lived in small tribes
and hunted, bringing to extinction the woolly
mammoth, American mastodon, giant bison, giant
ground sloth, glyptodont, horse, caribou, and camel, as
well as the saber-toothed cat, within 1,200 years of their
arrival on the continent. With the end of the Ice Age,
about 10,000 years ago, the large herds of various
Pleistocene animals disappeared, leaving the modern
animals for hunting, particularly the bison and deer.
Some groups turned to rudimentary agriculture and
fishing while others remained hunters and gatherers.
human entry into the Americas. It was formerly believed
that the Clovis people of 12,000 years ago were the first to
cross the Bering Land Bridge. Also, disputed evidence for
human occupation at the Pedra Furada rock shelter in
Brazil is dated to 30,000 years ago (see C. Renfrew and P.
Bahn, 1996, p. 298).
12
13