Edward R. Henry

ABSTRACT Magnetic gradiometry and in‐phase electromagnetic induction (EM) instruments were employed during a geophysical survey to identify archaeological features at an Adena circular ditch and embankment earthwork site. Three features identified in the geophysical survey were selected for further geophysical examination because of their shape, spatial arrangement... [view more]

ABSTRACT

Magnetic gradiometry and in‐phase electromagnetic induction (EM) instruments were employed during a geophysical survey to identify archaeological features at an Adena circular ditch and embankment earthwork site. Three features identified in the geophysical survey were selected for further geophysical examination because of their shape, spatial arrangement, and differences in the gradiometer and EM data. Downhole magnetic susceptibility was used to explore the subsurface shape of these features and to identify the presence of magnetic variations within them. Excavation of these features exposed a buried ground surface below the earthwork's embankment, a midden‐like soil in the ditch, and a large pit situated over a spring/seep inside the earthwork. Magnetic susceptibility data were collected on open wall profiles of excavation units with a KT9 kappameter. Pairing the geophysical results and excavation profiles helped separate a lightly burned ground surface from a buried A horizon below the embankment, map the buried A horizon beneath areas where the embankment is now destroyed, and separate natural from cultural fill episodes inside the pit feature. Correlations between the magnetic susceptibility data and drawn profiles identified specific cultural contexts for radiocarbon dating. The radiocarbon chronology of the site indicates the earthwork was constructed during Middle Adena ritual development (150 bc to ad 1), a time marked by increasing ritual diversity and the appearance of circular structures used in mortuary ritual. This research also demonstrated that the Woodland earthwork was reused by Late Fort Ancient peoples after approximately ad 1450. Copyright © 2011 John Wiley & Sons, Ltd.

Rinita A. Dalan; Bruce W. Bevan; Dean Goodman; Dan Lynch; Steven De Vore; Steve Adamek; Travis Martin; George Holley; Michael Michlovic

ABSTRACT Information on depth may be gained through the analysis of geophysical maps, by utilizing soundings, pseudosections, or time‐slices, or via the application of downhole measurements. Various methods and techniques were compared at the Biesterfeldt site, a proto‐historic earth‐lodge village in the Northern Plains... [view more]

ABSTRACT

Information on depth may be gained through the analysis of geophysical maps, by utilizing soundings, pseudosections, or time‐slices, or via the application of downhole measurements. Various methods and techniques were compared at the Biesterfeldt site, a proto‐historic earth‐lodge village in the Northern Plains, USA. Both traditional and more experimental approaches were used, including ground‐penetrating radar time slices and overlay analyses, a resistivity pseudosection, two‐ and three‐dimensional magnetic and resistivity modelling, and downhole tests of magnetic susceptibility, magnetic viscosity, total magnetic field, capacitance and resistivity. A direct‐push colour system, measuring the reflection of light over the red–green–blue (RGB) and near‐infrared spectrum, provided another useful tool for mapping the depths of archaeological features and stratigraphic layers.

Geert Verhoeven; Michael Doneus

ABSTRACT Scientists from different research disciplines have provided essential information that relates the biophysical characteristics of plants to their spectral reflectance. This fundamental understanding has facilitated the development of various non‐destructive sensing methods for detecting vegetation stresses, monitoring plant growth and calculating crop yield. Aerial archaeologists flying ... [view more]

ABSTRACT

Scientists from different research disciplines have provided essential information that relates the biophysical characteristics of plants to their spectral reflectance. This fundamental understanding has facilitated the development of various non‐destructive sensing methods for detecting vegetation stresses, monitoring plant growth and calculating crop yield. Aerial archaeologists flying in small aeroplanes have only partially exploited this knowledge. Instead of basing archaeological interpretation on only direct visual inspection of the conventionally acquired colour photographs, this contribution briefly reviews the reflectance properties of plants and uses them to present a new low‐cost imaging technique beneficial for the detection of (faint) archaeologically induced vegetation marks. The new approach consists of three simultaneously operated digital still cameras, each of them capturing information in a different spectral waveband: the visible, near‐infrared and red‐edge spectral region. The latter two bands are used in the calculation of a R ₇₀₀/R ₈₀₀ vegetation index. Besides a theoretical underpinning, real‐world examples will assess the potential of this new approach in detection of vegetation marks and prove that this low‐cost, multispectral method might be beneficial in identifying and enhancing weak crop stresses that are lost when taking only the broad visible spectrum into account. In the final discussion, some thoughts on future archaeological aerial research are given. Copyright © 2011 John Wiley & Sons, Ltd.

Keith Challis; Paolo Forlin; Mark Kincey

ABSTRACT A range of techniques have become established for the visualization and analysis of airborne LiDAR elevation data within the field of archaeology. In this paper we discuss the visualization of test data representing archaeological features in a variety of terrains using a suite of techniques, all available through... [view more]

ABSTRACT

A range of techniques have become established for the visualization and analysis of airborne LiDAR elevation data within the field of archaeology. In this paper we discuss the visualization of test data representing archaeological features in a variety of terrains using a suite of techniques, all available through generic geographical information system or image processing software. These comprise elevation shading using constrained colour ramps, slope analysis, hill‐shading, principal component analysis of multi‐azimuth hill‐shading, local relief models and solar insolation modelling. The strengths and weaknesses of each technique are discussed and a generic toolkit, suited to the visualization of airborne LiDAR data for archaeological purposes, is presented. Copyright © 2011 John Wiley & Sons, Ltd.

Meriç Aziz Berge; Mahmut Göktuğ Drahor

ABSTRACT To determine the data acquisition and inversion capabilities of electrical resistivity tomography (ERT), which is used in multilayered archaeological settlements, an ERT survey was carried out at the Old Smyrna Höyük site, in the city of İzmir, Turkey. This site dates from the third millennium ... [view more]

ABSTRACT

To determine the data acquisition and inversion capabilities of electrical resistivity tomography (ERT), which is used in multilayered archaeological settlements, an ERT survey was carried out at the Old Smyrna Höyük site, in the city of İzmir, Turkey. This site dates from the third millennium bc and ERT applications were performed using five different arrays (Wenner–alpha, Wenner–Schlumberger, dipole–dipole, pole–pole and pole–dipole). The resistivity distribution of the subsurface was investigated by two‐dimensional and three‐dimensional inversion routines, which use data obtained along orthogonal lines. To test the inversion treatments, ‘semi‐fully three‐dimensional’ and ‘quasi‐three‐dimensional’ approaches were also investigated, and comparison indicated a clear distinction between them. The results show that the quasi‐three‐dimensional solution had insufficient resolution, whereas the semi‐fully three‐dimensional data sets provide interpretable images of the subsurface. In addition, the effects of electrode array type and line interval and orientation were tested to define suitable ERT survey strategies for multilayered archaeological settlements. The array investigations show that dipole–dipole, pole–pole and pole–dipole arrays presented better quality images than the others. The line orientation tests performed in two perpendicular directions (N–S and E–W oriented lines) show that the N–S oriented lines are more suitable in terms of defining the buried architectural plan of Old Smyrna Höyük according to depth‐slicing visualizations. However, the combination of the two perpendicular data sets could be useful if large between‐line intervals are used. Finally, this ERT study clearly revealed the layered stratigraphy of Old Smyrna Höyük. Copyright © 2011 John Wiley & Sons, Ltd.

Jürg Leckebusch

ABSTRACT When interpreting large area ground‐penetrating radar (GPR) surveys it has been found that the depolarization of electromagnetic waves affects the reflectivity of some subsurface features, which has a larger effect on detectability than previously thought. This depolarization can make some archaeological structures almost invisible using standard... [view more]

ABSTRACT

When interpreting large area ground‐penetrating radar (GPR) surveys it has been found that the depolarization of electromagnetic waves affects the reflectivity of some subsurface features, which has a larger effect on detectability than previously thought. This depolarization can make some archaeological structures almost invisible using standard processing steps including reflection profiles and energy slice maps. Only recording data with orthogonal antenna orientation will eliminate this problem. After three‐dimensional interpretation of three‐dimensional volumes of GPR reflections a variable width gap between floors and their bounding walls has been repeatedly observed. This newly detected problem is clearly visible in a number of surveys conducted at a Roman town in Switzerland. It is explained by the distorted geometry of the sides of the floors common in the Roman Empire, resulting in a reflection surface that reflects most energy away from the surface antennae and only limited energy is recorded, making portions of the floors invisible. Copyright © 2011 John Wiley & Sons, Ltd.