|
|
| |
|
|
| |
|
|
|
|
| |
 |
| Extensive
excavations at Beit She'an, Israel. |
Archaeology
Archaeology is the study of the past by looking for the
remains and artifacts (historical things) left by the
people who lived long ago. These remains can include old
coins, tools, buildings, and inscriptions.
Archaeologists, the people who study archaeology, use
these remains to understand how people lived.
Archaeologists think it is important to understand the
past, because so many people use the past to know where
they come from.
Fields of interest
Archaeologists do not all study the same civilizations,
they specialize in different areas of interest. Some
fields of interest include Ancient Egypt (these
specialists are called Egyptologists), Ancient China, or
the Vikings. Archaeologists study every civilization
that is known, especially the ones where there is no
written history. They can study any time period. For
example, one might study the beginning of human life in
Africa, or study World War II. Marine archaeologists
study things that are now underwater. They search for
sunken ships or cities that have been lost under the
sea.
Sites
Stonehenge, in England, is a famous archaeological site,
or place. Other famous sites include the Roman Forum,
Angkor Wat, Machu Picchu, and Great Zimbabwe. In many
countries, governments and other groups of people
protect important sites so that they will not be
destroyed and so that visitors can always come and see
them.
Sometimes archaeological sites are found when
foundations are dug for new buildings. Archaeologists
have to work quickly when this happens, because people
who are building often don't have a lot of time. Many
times as soon as the archaeologists are done with their
work, the remains that they have found will be covered
over, unless they are very important. |
|
Methods
An archaeological investigation usually involves several
distinct phases, each of which employs its own variety
of methods. Before any practical work can begin,
however, a clear objective as to what the archaeologists
are looking to achieve must be agreed upon. This done, a
site is surveyed to find out as much as possible about
it and the surrounding area. Second, an excavation may
take place to uncover any archaeological features buried
under the ground. And, third, the data collected from
the excavation is studied and evaluated in an attempt to
achieve the original research objectives of the
archaeologists. It is then considered good practice for
the information to be published so that it is available
to other archaeologists and historians, although this is
sometimes neglected.
Remote sensing
Before actually starting to dig in a location, remote
sensing can be used to look where sites are located
within a large area or provide more information about
sites or regions. There are two types of remote sensing
instruments—passive and active. Passive instruments
detect natural energy that is reflected or emitted from
the observed scene. Passive instruments sense only
radiation emitted by the object being viewed or
reflected by the object from a source other than the
instrument. Active instruments emit energy and record
what is reflected. Satellite imagery is an example of
passive remote sensing. Here are two active remote
sensing instruments:
Lidar (Light Detection and Ranging) A lidar uses a laser
(light amplification by stimulated emission of
radiation) to transmit a light pulse and a receiver with
sensitive detectors to measure the backscattered or
reflected light. Distance to the object is determined by
recording the time between the transmitted and
backscattered pulses and using the speed of light to
calculate the distance travelled. Lidars can determine
atmospheric profiles of aerosols, clouds, and other
constituents of the atmosphere.
Laser Altimeter A laser altimeter uses a lidar (see
above) to measure the height of the instrument platform
above the surface. By independently knowing the height
of the platform with respect to the mean Earth's
surface, the topography of the underlying surface can be
determined.
Field survey
The archaeological project then continues (or
alternatively, begins) with a field survey. Regional
survey is the attempt to systematically locate
previously unknown sites in a region. Site survey is the
attempt to systematically locate features of interest,
such as houses and middens, within a site. Each of these
two goals may be accomplished with largely the same
methods.
Survey was not widely practiced in the early days of
archaeology. Cultural historians and prior researchers
were usually content with discovering the locations of
monumental sites from the local populace, and excavating
only the plainly visible features there. Gordon Willey
pioneered the technique of regional settlement pattern
survey in 1949 in the Viru Valley of coastal Peru, and
survey of all levels became prominent with the rise of
processual archaeology some years later.
Survey work has many benefits if performed as a
preliminary exercise to, or even in place of,
excavation. It requires relatively little time and
expense, because it does not require processing large
volumes of soil to search out artifacts. (Nevertheless,
surveying a large region or site can be expensive, so
archaeologists often employ sampling methods.) As with
other forms of non-destructive archaeology, survey
avoids ethical issues (of particular concern to
descendant peoples) associated with destroying a site
through excavation. It is the only way to gather some
forms of information, such as settlement patterns and
settlement structure. Survey data are commonly assembled
into maps, which may show surface features and/or
artifact distribution.
The simplest survey technique is surface survey. It
involves combing an area, usually on foot but sometimes
with the use of mechanized transport, to search for
features or artifacts visible on the surface. Surface
survey cannot detect sites or features that are
completely buried under earth, or overgrown with
vegetation. Surface survey may also include
mini-excavation techniques such as augers, corers, and
shovel test pits. If no materials are found, the area
surveyed is deemed sterile.
Aerial survey is conducted using cameras attached to
airplanes, balloons, UAVs, or even Kites. A bird's-eye
view is useful for quick mapping of large or complex
sites. Aerial photographs are used to document the
status of the archaeological dig. Aerial imaging can
also detect many things not visible from the surface.
Plants growing above a buried man made structure, such
as a stone wall, will develop more slowly, while those
above other types of features (such as middens) may
develop more rapidly. Photographs of ripening grain,
which changes colour rapidly at maturation, have
revealed buried structures with great precision. Aerial
photographs taken at different times of day will help
show the outlines of structures by changes in shadows.
Aerial survey also employs ultraviolet, infrared,
ground-penetrating radar wavelengths, LiDAR and
thermography.
Geophysical survey can be the most effective way to see
beneath the ground. Magnetometers detect minute
deviations in the Earth's magnetic field caused by iron
artifacts, kilns, some types of stone structures, and
even ditches and middens. Devices that measure the
electrical resistivity of the soil are also widely used.
Archaeological features whose electrical resistivity
contrasts with that of surrounding soils can be detected
and mapped. Some archaeological features (such as those
composed of stone or brick) have higher resistivity than
typical soils, while others (such as organic deposits or
unfired clay) tend to have lower resistivity.
Although some archaeologists consider the use of metal
detectors to be tantamount to treasure hunting, others
deem them an effective tool in archaeological surveying.
Examples of formal archaeological use of metal detectors
include musketball distribution analysis on English
Civil War battlefields, metal distribution analysis
prior to excavation of a 19th-century ship wreck, and
service cable location during evaluation. Metal
detectorists have also contributed to archaeology where
they have made detailed records of their results and
refrained from raising artifacts from their
archaeological context. In the UK, metal detectorists
have been solicited for involvement in the Portable
Antiquities Scheme.
Regional survey in underwater archaeology uses
geophysical or remote sensing devices such as marine
magnetometer, side-scan sonar, or sub-bottom sonar. |
|
Excavation
Archaeological excavation existed even when the field
was still the domain of amateurs, and it remains the
source of the majority of data recovered in most field
projects. It can reveal several types of information
usually not accessible to survey, such as stratigraphy,
three-dimensional structure, and verifiably primary
context.
Modern excavation techniques require that the precise
locations of objects and features, known as their
provenance or provenience, be recorded. This always
involves determining their horizontal locations, and
sometimes vertical position as well (also see Primary
Laws of Archaeology). Likewise, their association, or
relationship with nearby objects and features, needs to
be recorded for later analysis. This allows the
archaeologist to deduce which artifacts and features
were likely used together and which may be from
different phases of activity. For example, excavation of
a site reveals its stratigraphy; if a site was occupied
by a succession of distinct cultures, artifacts from
more recent cultures will lie above those from more
ancient cultures.
Excavation is the most expensive phase of archaeological
research, in relative terms. Also, as a destructive
process, it carries ethical concerns. As a result, very
few sites are excavated in their entirety. Again the
percentage of a site excavated depends greatly on the
country and "method statement" issued. Sampling is even
more important in excavation than in survey.Sometimes
large mechanical equipment, such as backhoes (JCBs), is
used in excavation, especially to remove the topsoil
(overburden), though this method is increasingly used
with great caution. Following this rather dramatic step,
the exposed area is usually hand-cleaned with trowels or
hoes to ensure that all features are apparent.
The next task is to form a site plan and then use it to
help decide the method of excavation. Features dug into
the natural subsoil are normally excavated in portions
to produce a visible archaeological section for
recording. A feature, for example a pit or a ditch,
consists of two parts: the cut and the fill. The cut
describes the edge of the feature, where the feature
meets the natural soil. It is the feature's boundary.
The fill is what the feature is filled with, and will
often appear quite distinct from the natural soil. The
cut and fill are given consecutive numbers for recording
purposes. Scaled plans and sections of individual
features are all drawn on site, black and white and
colour photographs of them are taken, and recording
sheets are filled in describing the context of each. All
this information serves as a permanent record of the
now-destroyed archaeology and is used in describing and
interpreting the site.
Analysis
Once artifacts and structures have been excavated, or
collected from surface surveys, it is necessary to
properly study them. This process is known as
post-excavation analysis, and is usually the most
time-consuming part of an archaeological investigation.
It is not uncommon for final excavation reports for
major sites to take years to be published.
At a basic level of analysis, artifacts found are
cleaned, catalogued and compared to published
collections. This comparison process often involves
classifying them typologically and identifying other
sites with similar artifact assemblages. However, a much
more comprehensive range of analytical techniques are
available through archaeological science, meaning that
artifacts can be dated and their compositions examined.
Bones, plants, and pollen collected from a site can all
be analyzed using the methods of zooarchaeology,
paleoethnobotany, and palynology, while any texts can
usually be deciphered.
These techniques frequently provide information that
would not otherwise be known, and therefore they
contribute greatly to the understanding of a site.
Computational and virtual
archaeology
Computer graphics are now used to build virtual 3D
models of sites, such as the throne room of an Assyrian
palace or ancient Rome. Photogrammetry is also used as
an analytical tool, and digital topographical models
have been combined with astronomical calculations to
verify whether or not certain structures (such as
pillars) were aligned with astronomical events such as
the sun's position at a solstice. Agent-based modeling
and simulation can be used to better understand past
social dynamics and outcomes. Data mining can be applied
to large bodies of archaeological 'grey literature'. |
|
Drones
Archaeologists around the world use drones to speed up
survey work and protect sites from squatters, builders
and miners. In Peru, small drones helped researchers
produce three-dimensional models of Peruvian sites
instead of the usual flat maps – and in days and weeks
instead of months and years.
Drones costing as little as £650 have proven useful. In
2013, drones have flown over at least six Peruvian
archaeological sites, including the colonial Andean town
Machu Llacta 4,000 metres (13,000 ft) above sea level.
The drones continue to have altitude problems in the
Andes, leading to plans to make a drone blimp, employing
open source software.
Jeffrey Quilter, an archaeologist with Harvard
University said, "You can go up three metres and
photograph a room, 300 metres and photograph a site, or
you can go up 3,000 metres and photograph the entire
valley."
In September 2014 drones weighing about 5 kg (11 lb)
were used for 3D mapping of the above-ground ruins of
the Greek city of Aphrodisias. The data is being
analysed by the Austrian Archaeological Institute in
Vienna. |
|
 Kiddle: Archaeology
Wikipedia: Archaeology |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
Search Fun Easy English |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
About
Contact
Copyright
Resources
Site Map |
