Field Survey Techniques in Archaeology
Finding the remnants of past civilizations requires a systematic approach to land analysis. A field survey is a primary method used by archaeologists to locate sites, involving the careful analysis of land and the search for artifacts. According to the Archaeological Institute of America, these searches often target areas likely to have supported human populations or locations identified in historical documents and records.
Surveys provide a foundational map for future research. When time or funding is limited during the initial discovery, archaeologists can return to these identified sites to conduct deeper excavations and determine the full extent of the area. In some instances, researchers may employ random sampling within a specific area of land to identify potential sites.
[ไม่มีภาพประกอบ]Key Facts
- Field surveys identify where people lived at various points in history through land analysis and artifact hunting.
- Geophysics allows researchers to investigate subsurface features without immediate digging.
- GIS (Geographical Information Systems) integrates locational and archival data to map discoveries.
- Ecofacts are biological materials resulting from human activity that were not deliberately modified.
- Post-depositional factors, such as wind (aeolian) or water (alluvial) processes, help preserve sites by burying them in sediment.
Geophysical Survey Methods
Geophysics is an increasingly popular branch of surveying that uses specialized instruments to investigate features beneath the ground surface. While these tools provide a glimpse into the subsurface, they are not entirely reliable on their own; archaeologists must still excavate the area to confirm the findings.
Magnetometry
Magnetometry is the process of measuring and mapping patterns of magnetism in the soil. This technique requires a magnetometer to detect and map specific traces of soil magnetism that may indicate human-made structures.
Ground Penetrating Radar (GPR)
Ground penetrating radar uses radar pulses to create images of the subsurface. By utilizing electromagnetic radiation in the microwave band of the radio spectrum, GPR detects reflected signals from structures buried underground.
[ไม่มีภาพประกอบ]Mapping and Data Integration
Locating artifacts is only one part of the process; archaeologists must also create accurate maps. By combining survey data and archival research, they use Geographical Information Systems (GIS). This tool stores both locational information and a variety of other data points.
GIS is invaluable for researchers exploring new areas, as it allows them to see previous research and existing discoveries. This collaborative data allows archaeologists to expand their research and build upon previous findings.
Defining the Archaeological Site
Traditionally, a site is identified by the presence of artifacts (man-made objects) and features (non-portable remains, such as houses or hearths). Additionally, researchers look for ecofacts—biological materials like bones, scales, or feces that result from human activity but were not modified by humans.
The definition of a "site" can vary based on the era and the researcher's perspective:
- Prehistoric eras: In the Palaeolithic and Mesolithic periods, a simple scatter of flint flakes can constitute a site.
- Landscape archaeology: This approach views discrete units of human activity (such as a town and its cemetery) within the context of the wider environment rather than as separate, demarcated areas.
- Geoarchaeology: Environmental archaeologists may consider a sequence of natural organic or geological deposition a site worthy of study, even in the absence of human activity.
Site Formation and Preservation
While most sites form through human processes, they are often preserved by natural post-depositional factors. Buried remnants are generally better preserved than those exposed to the elements. Natural sediment deposition occurs through several processes:
- Alluvial: Water-related sediment deposition.
- Aeolian: Wind-related sediment deposition.
- Vegetative: Decomposed plant matter in jungles creating soil layers.
- Colluviation: The burial of a site by "hillwash," or sediments moved by gravity on slopes.
Human activity also contributes to site burial, as newer structures are frequently built atop older ones. This specific challenge has led to the development of urban archaeology.
[ไม่มีภาพประกอบ]| Tool/Method | Primary Function | Key Characteristic |
|---|---|---|
| Field Survey | Site identification | Walking, analyzing land, and random sampling |
| Magnetometry | Subsurface mapping | Measures soil magnetism patterns |
| GPR | Subsurface imaging | Uses microwave radio spectrum pulses |
| GIS | Data integration | Combines locational and archival information |
Frequently Asked Questions
What is the difference between an artifact and an ecofact?
An artifact is a man-made object, whereas an ecofact is a biological material (such as bone or feces) that resulted from human activity but was not deliberately modified by humans.
Why is digging still necessary if geophysics can see underground?
Geophysical tools like GPR and magnetometry do not produce a perfect picture. Archaeologists must still excavate the area to uncover the truth and verify the subsurface features.
How does GIS help archaeologists?
GIS allows archaeologists to plug in survey and archival data to see what has already been discovered in a specific area, helping them avoid duplicating work and expand existing research.
What is colluviation?
Colluviation is the burial of an archaeological site by sediments moved by gravity, a process often referred to as hillwash, typically occurring on slopes.
What is the focus of urban archaeology?
Urban archaeology specifically deals with sites where human activity has resulted in newer structures being built directly on top of older remains.