5.5 KiB
| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Archaeology | 5/11 | https://en.wikipedia.org/wiki/Archaeology | reference | science, encyclopedia | 2026-05-05T15:06:27.665454+00:00 | kb-cron |
An archaeological investigation usually involves several distinct phases, each employing a variety of methods. Before any practical work can begin, however, a clear objective for what the archaeologists are seeking to achieve must be agreed upon. This done, a site is surveyed to learn as much as possible about it and its surroundings. Second, an excavation may be conducted to uncover any buried archaeological features. And third, the information collected during the excavation is studied and evaluated to achieve the archaeologists' original research objectives. 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 at a location, remote sensing can be used to identify where sites are located within a large area or to provide more information about sites or regions. There are two types of remote sensing instruments—passive and active. Passive instruments detect natural energy reflected or emitted by 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 the reflections. Satellite imagery is an example of passive remote sensing. Here are three active remote sensing instruments:
Lidar: Lidar (light detection and ranging) 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. The 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 atmospheric constituents.
Laser altimeter: A laser altimeter uses a lidar (see above) to measure the height of the instrument platform above the surface. By independently determining the platform's height relative to Earth's mean surface, the topography of the underlying surface can be determined. 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 flew 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 Austrian Archaeological Institute in Vienna is analysing the data.
=== Field survey ===
The archaeological project then continues (or begins) with a field survey. A regional survey is an attempt to locate previously unknown sites within a region systematically. A site survey is an 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. Surveys were not widely practised in the early days of archaeology. Cultural historians and earlier researchers were usually content to discover the locations of monumental sites from the local populace and to excavate 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 involve processing large volumes of soil to search for 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 a surface survey. It involves combing an area, usually on foot but sometimes using 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.