ANTH 235,
DATA COLLECTION: RECONNAISSANCE & SURVEY
Reconnaissance refers strictly to locating and identifying
archaeological sites (“putting spots on a map”).
Survey is undertaken to record as much as possible about
archaeological sites without excavation.
“Off-site” or “non-site” evidence: plow marks, surface
scatters of artifacts, field boundaries, roads, irrigation
canals, quarries and mines, etc.
Landscape archaeology
Discovering archaeological sites & features
(ground reconnaissance & aerial reconnaissance)
documentary sources, maps and place-names, salvage
archaeology (also known as rescue archaeology)
In the past few decades, reconnaissance has developed
from being simply a preliminary stage in fieldwork
(looking for appropriate sites to excavate) to an
independent line of inquiry – an area of research in its own
right.
There are two kinds of ground reconnaissance:
unsystematic and systematic
Reconnaissance and excavation are not mutually
exclusive activities. Excavation tells us a lot about a
little part of a site, and can only be done once,
whereas reconnaissance tells us a little about a lot of
sites, and can be repeated.
AERIAL RECONNAISSANCE & REMOTE SENSING
What is revealed by aerial photographs?
1. Earthworks: banks and associated ditches or stonewalled features. Usually revealed from the air as
shadow-marks. Time of day and season are obviously
important.
Traces of ditch-and-bank fortification at Ivolga, a third-century BCE fortress
in southern Siberia, are barely visible even under optimal conditions (oblique
lighting, low vegetation, no deep snow). Features such as these are often
more visible in aerial photos than they are on the ground.
2. Soil-marks: reveal the presence of buried ditches, banks,
or foundations by changes in sub-soil color. They
mostly occur in agricultural zones, so many sites of this
type have been or are being destroyed.
Circular defensive (?) structure in central Poland revealed by soil-marks. A
modern dirt road runs diagonally through the lower left corner of the image.
3. Crop-marks: develop when a buried wall, ditch, or road
either decreases or enhances crop growth by affecting
availability of water and nutrients through changing the
depth and composition of soil.
Linear ditch at Alfred’s Castle, Oxfordshire, England revealed by crop-marks.
4. Larger-scale patterns: aerial photography can put
seemingly random distributions of sites in association by
establishing systems of interconnecting roads or
relationships between sites and local resources (water,
raw materials, arable land; “Nazca Lines,” Peru, below).
RECENT DEVELOPMENTS & NEW DIRECTIONS:
 digital image capture – resolution still rather low for
archaeological applications, but great near-term potential
 digital enhancement of imagery
 manipulation of spatial data and imagery in a Geographic
Information System (GIS)
 new photographic films, especially those with emulsions
sensitive to the infrared portion of the spectrum
REMOTE SENSING FROM HIGH ALTITUDE:
 two principal sources of data: various satellite systems
and the American Space Shuttle
 two principal types of data: photography and radar
 among satellites, the American Landsat and WorldView,
the French Système Probatoire d’Observation de la Terre
(SPOT), the Russian Ikonos, and the Japanese Radarsat
systems are among the most useful
 problems: low spatial resolution (variable, but mostly
no better than 10 meters. There is great potential here:
current technology available within the intelligence
community allows ground resolution on the order of only
5-10 cm!) and very high cost
SUB-SURFACE DETECTION:
 probes: probing the soil with rods or borers. Still very
common.
 non-destructive techniques: geophysical remote sensing
devices that either pass energy of various kinds through
the soil to “read” what lies below the surface, or measure
variability in the earth’s magnetic field.
approaches include: echo-sounding, groundpenetrating radar, electrical resistivity, metal
detectors, and magnetic survey (below).
(Above): Magnetic survey being undertaken at the Iron Age Pen y
Cloddiau Hill Fort, near Nannerch, Wales using a dual sensor
Magnetic Gradiometer. The instrument consists of two fluxgates
very accurately aligned to nullify the effects of the Earth’s
magnetic field. Readings relate the difference in localized
magnetic anomalies with the general magnetic background. The
instrument consists of two high-stability fluxgate gradiometers
suspended on a single frame. Each sensor has a one meter
separation between the sensing elements giving a strong response
to deeply buried anomalies.
See:
http://www.homeusers.prestel.co.uk/aspen/sussex/georesistivity.html
A sophisticated gradiometer/magnetometer array being used
on archaeological survey
 underwater archaeology: sonar, magnetic anomaly
detection, sub-bottom profiling (radar)
Hull-mounted multibeam sonar (left) and
towed side-scan sonar array (right)
The Stalinets-class Soviet submarine, S7, sunk by the Finnish submarine Vesihiisi
in summer 1942. In July 1998, the S7 was located with side-scan sonar at a depth
of 40-45 meters off Söderarm in the Stockholm archipelago. The 78-meter long
sub is intact except for the stern, where the Vesihiisi’s torpedo impacted. The
conning tower and the stern hatches are closed, and no one has entered the vessel
thus far. Before she was hit, the S7 had closed all interior hatches and was
preparing to dive, so portions of the interior, now a grim grave, may still be dry.
(Sonogram by Sture Hultquist)
See also: http://www.abc.se/~m10354/uwa/s7.htm and
http://www.abc.se/~m10354/publ/submarin.htm
CONCLUSION
Reconnaissance, survey, and excavation do not represent an
operational chain (as in “First we reconnoiter things, then
we conduct a survey; finally we excavate…” NO!)
These activities are carried out synergistically in
conjunction with one another and, increasingly,
reconnaissance and survey are employed in lieu of outright
excavation.
To read more about this topic, you might enjoy perusing:
Banning, E. B. (2002). Archaeological Survey. New York:
Kluwer Academic/Plenum Publishers.
ISBN: 0-306-47348-8.