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Learning About Archaeology
How an archaeological study begins
Winter dig site in central Iowa. |
Archaeologists
excavate, analyze, interpret and report on a sample of the sites found.
They select the sites to excavate after developing research plans
which serve as a written guide to their work. These plans include
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research questions and the steps needed to answer those questions.
Archaeologists rarely dig an entire site, because they have limited
funds and time. The research plan helps them decide what parts of a site
to dig. Archaeologists are very careful when developing the research plan,
because once a site is excavated it is destroyed.
In the research plan, archaeologists develop questions that might be
answered through excavation. For example: How did the people at the site
build their houses? Did they have contact with other cultures? How long
was the site occupied?
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Archaeologists
often use "hypothesis testing" to guide their research. In hypothesis
testing, a statement is made that can be tested when certain types
of artifacts and information are |
found. For example, the question - "What kind of crops were grown at this
site?" - would be stated as the hypothesis, "If corn were grown at this
site, then I would expect to find corn pollen, digging sticks, and grinding
tools to turn the corn into flour." If corn pollen, digging sticks and grinding
tools are found, then the archaeologists can conclude that corn was grown
at the site.
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Excavating the site
Site grids
Once archaeologists locate
a site they wish to dig, the first step is to lay out an excavation grid
using surveyor's tools and lots of flags, stakes and string. From above,
the site would look as though a sheet of graph paper had been superimposed
on it. The curved lines are elevations, and the grid shows up in the pattern
of the excavations.
The grid serves to help archaeologists
keep horizontal control of the excavation. Each square can be assigned
a number by any of several methods. All measurements can then be recorded
with reference to the square's location. A grid can cover anywhere from
a few to many thousand square meters.
Levels
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The grid
helps archaeologists keep horizontal control. Vertical controls are
ensured by the use of excavation levels. If you think of the site
as a cake, which has been cut into tidy squares by the grid, then
the vertical controls are the cake's layers. The simplest form of
excavating by levels is simply to work in evenly spaced, horizontal
levels. The usual thickness of an arbitrary level is about 4 inches. |
The arbitrary level is most useful when the site does not appear to have
clearly defined stratigraphy (a word referring to the layering of deposits
at the site). In more complex sites, where succeeding occupations have left
a more "cluttered" record, the use of excavation by stratigraphic level
is employed. One level might consist of a layer of wind-blown sand; the
one below it might be a thin deposit of burnt earth mixed with artifacts;
below that might be a layer of occasional artifacts embedded in an buried
topsoil.
Layers of earth escavated. |
The
combination of horizontal and vertical controls allows archaeologists
to keep track of the location of every item they find. Most simply,
they have a record of the grid square and level of a find. |
Such locational record keeping
is a necessary part of archaeology. Digging destroys a site. By keeping
accurate records of where artifacts are found and the location of other
features in the site, an archaeologist can ideally reassemble the site back
in the lab.
Artifacts
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Anything
which has been made by people is known as an artifact. It may be crude
pebble chopping tools used by our most remote ancestors, or a laptop
computer-both are artifacts. One of the |
archaeologist's goals is to recover
artifacts at a site. The
artifacts are one of the primary means by which we can understand past cultures.
They represent what is left of a technology. By understanding the technology
of a people, we are a step closer to understanding how they met the day-to-day
challenges of their environment.
Features
Besides artifacts, archaeologists
also excavate features. Essentially, a feature is something which cannot
be brought physically back to the lab. Features include such things as
post holes, storage pits, soil stains, fire hearths, an arrangement of
artifacts, a concentration of clam shells, and so forth. Careful attention
to the features at a site will provide the archaeologist with a much clearer
idea as to how a site was used.
Tools
Archaeologists
use many tools in their work. An archaeologist on a survey will use detailed
topographic maps of the survey area, as well as compasses and large measuring
tapes. The new GPS (Global Positioning Satellites) technology is becoming
common for detailed recording of site information.
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As
you might expect, the most common excavating tools are the shovel
and the mason's trowel. A skilled worker will use these these tools
to trim and scrape (not dig!) the soil from the site with virtually
no damage to the artifacts and features within it. When a more delicate
touch is required, wooden picks (bamboo
splinters are popular), spoons, dentist's picks, |
and brushes are useful. Tape
measures are constantly in use for mapping the locations of items and keeping
track of depths.
Record keeping
Archaeologists have to be good
observers. Much of what they know about a site comes from carefully watching
as they dig. But they cannot simply observe; they must write their observations
down. The most important tools archaeologists use at a site are graph
paper, notebooks and pencils or pens. Only by making written records can
archaeologists save and interpret the information they find. Why? Because
once an artifact is moved from its place in the dirt, it can never be
put back exactly where it was found, unless a record where the artifact
came from exists. Information about things such as houses and hearths
that cannot be picked up and moved, must be recorded on paper and with
photographs, because they will be destroyed in the process of digging.
If good records are not kept as a site is excavated, the information that
the sites can give us about the past is lost forever.
Screening
Excavated soil is sifted through screens, usually measuring 1/4" or 1/8".
This captures small items which may have been missed by the excavator.
Items found in the screen are kept with the rest of the material found
in each level of each unit. A smaller screen size can be used effectively
if a water hose is used to rinse the soil through the mesh. The technical
term for this is, of course, waterscreening. Very often, samples of soil
are also floated in water as part of the waterscreening process, which
recovers very tiny bits of charcoal, seeds and bone.
Other tools
Other, more exotic,
tools are also used by archaeologists. In recent years nondestructive
investigative techniques have been employed successfully at many sites.
These remote sensing techniques include magnetometers, resistivity measurements,
and ground penetrating radar. All of these can, under good conditions,
provide a sense of what features lie under the ground surface. They have
proven to be very helpful at locating the lines of buried walls, foundations,
earthlodge floors, and many other features.
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Analyzing the
findings
Chipped Stone
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Stone
is the raw material for humankind's oldest durable technology. More
than a million years ago, people learned that certain kinds of stone--those
related to flints--could be chipped into various sharp-edged forms
using hammer stones, bone or hardwood batons, and bone or antler flakers.
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The byproducts of chipping stone
tools include the cores of flint, chert, and other "knappable" stones and
flakes. Flakes and cores make up a great part of the items found in many
archaeological sites. Chipped stone tools are divided into several categories.
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One category includes finely finished tools such as projectile points
(both arrow and spear points), bifaces (knives), and drills. Another
is comprised of tools chipped on flakes, including various scrapers
(endscrapers, sidescrapers, and spokeshaves), engravers, shredders,
and miscellaneous cutting edges. |
Ground Stone
Ancient peoples learned
that, while not all types of stone could be chipped, nearly all could
be battered, pecked, or ground into shape by other stones. The earliest
ground stone artifacts included the mano and metate (handstone and milling
stone), for grinding seeds and other plant material. Another early ground
stone artifact was the atlatl weight, which was used to counterbalance
the atlatl or spearthrower.
By late prehistoric times,
ground stone tools included axes, celts, mauls and hammers, gaming pieces,
and tobacco pipes.
Pottery
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Pots
were made with local clays, usually tempered with crushed granite,
sand, or occasionally shell. It was worked into shape using the paddle
and anvil technique, where a round, smooth stone was held inside,
and the outside was worked with a wood |
or bone paddle. The paddle was
often covered in cord, fabric, or was cut in grooves or checks. Firing was
at low temperatures without the use of kilns.
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The
earliest pottery consisted of thick, cone-like vessels. The outside
surface was usually left roughened by cord or fabric paddle impressions;
decorations, when present,
usually were confined |
to the rim area and included
punctates (holes pushed partway through the pot), bosses (the other side
of the punctate), cord wrapping, and tool marks.
Later pots took on a globular
shape with flared rims. Smoothed, shell-tempered vessels with trailing
were in use by the Oneota peoples in the middle of the second millennium.
Other pottery implements included jars, bowls, and pipes.
One aspect of pottery which
archaeologists find very useful is that its style changes over time. This
has been very useful in sorting out different prehistoric cultures and
dating them.
Fauna and flora
Flora and fauna refer to plants
and animals. Both were doubly useful in that they provided not only food,
but material for tools, clothing, and housing.
The remains of animals and
plants at a site provide many clues as to what happened there. They can,
first off, provide information on exactly what was being eaten. Sometimes
you can also tell how animals were butchered and how food was prepared.
Other information can tell what time of year the site was occupied. An
examination of the plant pollen, insect remains, and tiny animals such
as snails can provide clues to the ecology of region and its climate in
ancient times.
Dating
A
question archaeologists commonly hear is "how do you know how old it is?"
Dating a site or artifact has always been one of the most important elements
in archaeological research. There are several ways which have been developed
over time.
Stratigraphic (relative)
dating - The oldest
method of dating is stratigraphic. As time passes, older layers of earth
and artifacts are covered by new ones. Thus it stands to reason that items
found in a higher stratigraphic position at a site are younger than those
below. By comparing the stratigraphic position of several sites, a picture
of the relative ages of various prehistoric cultures could be assembled.
This was how dating was primarily done before about 1950.
Radiocarbon dating
- Archaeological dating was revolutionized in the 1950s by the invention
of radiocarbon (also known as carbon-14 or 14C) dating. Basically, all
living things absorb carbon during their lives. The carbon absorbed contains
regular carbon (12C) and a small percentage of radioactive carbon (14C).
Over time, the radioactive isotope in the remains breaks down. Scientists
know that it takes about 5,500 years for half the carbon to break down.
By measuring the remaining radioactive carbon, researchers can thus calculate
the age of the item. Modern techniques have allowed dates to within a
few years of accuracy. Radiocarbon dating is most effective on items such
as wood charcoal. Items up to 30,000 or 40,000 years old can be reliably
dated. Carbon dates done these days are often calibrated against known
tree ring dates.
Other dating techniques
-Another form of dating which has proven effective is tree ring dating,
dendrochronology. Rings form in trees each year, in a pattern dependent
on variables such as precipitation, temperature, etc. By comparing a series
of trees, researchers in many areas have compiled master tree ring sequences.
Wood samples from sites can be compared to these to see where they fit
in the sequence, thus dating the site. Tree ring series have also been
used to help calibrate radiocarbon dating methods.
Other techniques for dating
sites exist. One is paleomagnetic dating. In this method, it is known
that the orientation of magnetic north has shifted steadily over time.
If an artifact (such as a freshly fired, unmoved pot) or feature (such
as a fire hearth with baked soil in it) can be found, the magnetic orientation
of particles in them can be measured and an approximate age estimated.
Another method, known as thermoluminescence, measures the energy stored
in an artifact once heated by fire. The measure of the remaining stored
energy is a measure of the age of the item. Yet another researcher has
developed a means of dating ancient rock art by measuring the varnish
(a form of weathering) which has formed on it. This is still an experimental
method, but it shows promise.
Associative dating
- Once a prehistoric culture has been dated by any one or more of the
above methods, similar groups of artifacts from other sites may be dated
by association. So when a collector brings an archaeologist an Agate Basin
point, it is relatively easy to say "that point is 10,000 to 10,500 years
old" because other Agate Basin sites have been dated both stratigraphically
and by radiocarbon.
Putting it all together
One
of the most exciting aspects of archaeology is taking all the clues provided
by artifact analysis, dating, animal remains, and so forth, and attempting
to reassemble a past culture.
Technology
Technology
is the point at which human cultures and their environments come together.
Each human society has developed its own technology to allow it to make
the best use of its surroundings. Since technology provides the only substantial
physical traces of human existence, it is what archaeologists deal with
the most.
The tools of everyday life
in ancient times provide clues. By studying how they are made we can determine
the underlying means of production, or by studying the raw materials we
can make deductions about the patterns of movement and exchange of peoples.
The arrangement of tools at
sites is also important. Certain combinations of artifacts might indicate
that plant foods were being gathered and processed. Other tool kits might
suggest hunting and butchering, clothing manufacture, hide or wood working,
and so forth. A pattern of different tool kits in use by the same people
at different places might aid archaeologists in reconstructing resource
use patterns and annual migrations.
Environment
Environment
is critical to human cultures both ancient and modern. Data provided by
pollen, seeds and other plant remains, and animals sensitive to environmental
conditions is vital in reconstructing past climates. Understanding ancient
climates is vital to determining what conditions faced early inhabitants.
For instance, mild winters and summers with ample precipitation would
be a great help to people who depend on farming or gardening.
Likewise, periods of great
heat and/or droughts can profoundly affect what use people can make of
the land. In the drier times people lived in more dispersed bands, living
on not only buffalo but, deer, rabbits, rodents, reptiles, and a much
greater reliance on plant foods.
Besides the overall reconstruction
of past climates, archaeologists are also interested in the local environment
at the time a site was occupied. Studies of the plant remains at a site
can reveal information on whether a site was situated on the edge of a
marsh, a streambank, open prairie, forest, and so forth. Soils also aid
in this work; different types of soils are typical of different environments.
The study of the geology at a site provides additional information on
the shape of the ancient landscape.
Lifestyles
The
above examples are part of the process used by archaeologists to reassemble
the jigsaw puzzle of the past. As the work at one site is compared to
other sites, or new information is gathered, a picture slowly emerges
and becomes refined about the lives of ancient people. Understanding the
technology, resources, climate, and surroundings allows an insight into
the life of a people, season by season and day by day over a long time
period. Cultural anthropologists have documented the amazing diversity
of human life on earth; archaeology expands on that by providing the vital
dimension of time.
Using Different Science
Methods
Besides the time-honored
archaeological practice of digging and sifting dirt to find artifacts,
researchers use the latest technology to analyze ancient plant and bone
remains. The sciences of geology, geography, paleontology, biology, botany,
and zooarchaeology are all represented in the probe of the distant past,
while the social sciences are prominent in research into more recent history.
Countless hours were spent reading old tax and census records, as well
as old newspapers, to track the lives of people long gone.
North American Time Periods
North American archaeologists
generally study two time periods. "Prehistoric" archaeologists focus on
the Native American past up to the time of contact with Europeans. "Historical"
archaeologists work from the time of European and Native American contact
to the present.
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Archaeology and
the law
Most countries, including
the United States, have laws designed to protect their archaeological
heritage. The U.S. federal government became concerned early in the 20th
century about the destruction and looting of Indian ruins in the West.
To protect these and other archaeological resources, Congress passed the
Antiquities Act which was enacted in 1906. With its passage, federal officials
were made responsible for protecting archaeological sites as public resources.
Further public concern for
archaeological preservation was raised in the 1940s, 1950s and 1960s during
the massive public-works programs of those eras. As a result, archaeological
sites were among those protected by the 1966 National Historic Preservation
Act.
In 1979 the Archaeological
Resources Protection Act (ARPA) was enacted. This statue expanded the
provisions of the 1906 act by establishing major criminal and civil penalties
for violators. In 1988 ARPA was amended to simplify prosecutions and to
make the intent to loot also a felony. In addition, the amendments required
federal agencies to undertake surveys of archeological resources and develop
or expand public education programs.
The National Historic Preservation
Act and the National Environmental Policy Act also require federal agencies
to evaluate their actions in light of the impact they will have on significant
archaeological resources.
Native American Graves
Protection and Repatriation Act
In
1990 the Native American Graves Protection and Repatriation Act was passed
by Congress and signed into law by President Bush. It requires federal
agencies and most museums in the United states to inventory the Native
American human remains, burial artifacts, sacred objects, and objects
formerly owned communally by tribes and to offer to return these to Indian
tribes that are clearly affiliated with them.
The Office of the State
Archaeologist (OSA)
Many
state governments, including Iowa, have also adopted statutes protecting
archaeological resources and regulating archaeological investigations
on their lands. In Iowa, the Office of the State Archaeologist (an organized
research unit of The University of Iowa) is designated by Iowa statute
to develop, disseminate, and preserve knowledge of Iowa's prehistory and
history through archaeological research, service and education.
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Protecting
Human Remains
The Office of the State Archaeologist
(OSA) is responsible for the investigation, interpretation, and preservation
of ancient burial grounds, and when necessary, the recovery and reburial
of ancient human skeletal remains. Chapter 263B of the Iowa Code protects
ancient human remains in Iowa. The OSA and Iowa Department of Transportation
works closely with the Indian community through an Indian Advisory Committee
to implement the law.
Ancient human remains are
those older than 150 years. Legal protection of burials in Iowa extends
to include prehistoric burial mounds and unmarked cemeteries. Sites are
preserved and protected whenever possible. If, however, human remains
have been or must be removed, the OSA disinters and examines the remains
prior to reburial.
Any individual who has found
a possible ancient burial site or skeletal material he or she suspects
may be human should contact the OSA. If the bones are determined to be
human, they will be examined by a physical anthropologist in an attempt
to determine cultural affiliation. A report will be written and submitted
to the Iowa Department of Health. If the remains are over 150 years old,
they will be reburied in one of four state cemeteries established for
that purpose.
Anyone concerned about encountering
burials should contact the OSA for assistance to ensure compliance with
Iowa law. Anyone with knowledge of disturbance of ancient human remains
should contact the OSA. Intentional disturbance of a burial is considered
criminal mischief in the third degree (Chapter 716.5, Iowa Code).
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Iowa's Burials
Program
The Office of the State Archaeologist's
Burials Program is dedicated to the protection of burial sites and human
remains, to the reburial of ancient human remains, and to achieving a
greater understanding of Iowa's past. All Iowans are served through the
program's protection of Iowa's heritage.
The Burials Program is involved
in numerous field projects throughout Iowa. Museums, other repositories,
and individuals also submit their collections for examination and reburial.
Since 1976, the program has handled over 1,200 field projects in 94 of
Iowa's 99 counties.
Field projects result in the
discovery of many new burial sites and acquisition of new information
on previously recorded sites. Field work involves verification of reports
of possible burials or mounds, as well as examination of mounds or mound
groups and other burials that are threatened by erosion, construction
or quarrying activities, or vandalism. Preservation of sites is always
the preferred treatment. In cases where significant sites are threatened,
the State Archaeologist has the authority to deny permission to disinter.
The remains of over 750 individuals
have been reburied since the program began. A cemetery on state-owned
land was dedicated and set aside for this purpose in 1977. A second cemetery
was established in 1979, a third in 1987, and a fourth in 1991. Remains
are reburied in the cemetery nearest to the original burial site, and
a ceremony is held at or shortly after each reburial in accordance with
the wishes of the Indian Advisory Committee. Repatriation of tribally
affiliated remains is conducted in compliance with the federal Native
American Graves Protection and Repatriation Act.
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"The Indian point of
view on exhumation can be stated in simple terms. Basically there
is rarely a good reason for removal of the dead from the ground
where they have rested so long and when it does become necessary
those human remains should be reburied as soon as possible and in
a proper and dignified manner. . . . Our ancestors were human and
we want them left alone. . . . We Indians respect our ancestors.
They are present in our ceremonies and we call upon them for help
to live our lives helping one another. . . . [They] were once people
who once walked on earth, loved, prayed, took care of their families,
died and were buried. . . . We believe that the dead should stay
buried. There is enough land for everything that needs to be done
so that a few acres left for our dead won't cause anyone to starve."
Maria Pearson, paper
entitled The Indian Point of View: Exhumation and Reburial.
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Teaching
Iowans about Archaeology
Bringing archaeology into
the classroom is a great tool to teach history, social studies, biology,
science, communication, geography, and anthropology, and to encourage
and enhance critical thinking skills and teamwork. Information available
through this site and the related links can provide parents and teachers
with an excellent starting place to teach their children and students
about Iowa's rich resources.
Bringing
it all Together
Hopefully you've learned something about archaeology.
Archaeology is usually not as glamourous as the Indiana Jones movies would
suggest. Rarely do archaeologist find golden objects. Much of the work
is tedious and time consuming. Excavation can be dirty and frustrating.
Yet the past is something that we should all be interested in learning
more about. The finds are the product of human behavior made by people
who were not unlike ourselves in many ways. They may have lived in a different
culture, but they were human. They tell their story through what they
made and left for us. The ultimate quest of archaeological research is
to find cause and effect explanations of human behavior over the centuries
to help us understand the present.
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