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Cover
Title page
About the Author
Acknowledgments
1 Introduction to Ground-penetrating Radar in Geoarchaeology Studies
1. Introduction
2. Scales and Applications of Geoarchaeological Studies with GPR
3. Basics of the GPR Method
4. Integrating GPR with the Geological and Archaeological Record
5. References
2 Basic Method and Theory of Ground-penetrating Radar
1. Introduction
2. Production of Reflections, Depth of Penetration, and Resolution
3. Data Collection and Recording
4. Production and Processing of Reflection Profiles
5. More Advanced Data Processing Steps
6. Interpretation of GPR Reflections in Profiles
7. Resolution of Stratigraphic Units
8. Weather and Moisture Differences as They Affect Resolution
9. References
3 Integration of Geology, Archaeology, and Ground-penetrating Radar
1. Introduction
2. Examples of Correlating Radar Reflections to Define Stratigraphic Interfaces
3. References
4 Fluvial, Alluvial Fan, and Floodplain Environments
1. Introduction
2. Fluvial Systems
3. Fluvial Terraces
4. Alluvial Fans
5. References
5 Soils Horizons, Peat Bogs, and Swamps
1. Introduction
2. Soil Horizons
3. Swamps and Peat Bogs
4. References
6 Beaches, Sand Dunes, and other Coastal Environments
1. Introduction
2. Beaches
3. Erosion Features along Coasts
4. Lagoon and Tidal Flats
5. Aeolian Dunes
6. References
7 Lakes and Deltas
1. Introduction
2. Lakes
3. Deltas
4. References
8 Caves and Rock Shelters
1. Introduction
2. Rock Shelters
3. Mapping Adjacent to Rock Shelters
4. Caves
5. References
9 Anthropogenic Features and Urban Environments
1. Introduction
2. Middens
3. Anthropogenic Deposits
4. Urban Settings
5. References
10 Conclusions
1. Collection of Data for this Book and the Future of GPR in Geoarchaeology
2. Environments Where GPR is Most Applicable in Geoarchaeology
3. The Future of GPR in Geoarchaeology
4. References
Glossary of Common GPR Terms
Index
End User License Agreement

List of Illustrations

Chapter 01
1. Figure 1.1 Collecting GPR profiles with a GSSI SIR-3000 control system and 270 MHz antennas.
2. Figure 1.2 Comparison of a 400 MHz reflection profile collected within a 50 ns time window to a 3 m thick outcrop of cross-bedded aeolian dune sands with a burned house floor. Reflection energy spreads from the surface transmission antenna, creating an average of reflections received back at the ground surface from subsurface interfaces.
3. Figure 1.3 Location of the GPR reflection profile used to place Paleolithic artifacts into a geological context in western Portugal.
4. Figure 1.4 Two hundred and seventy megahertz reflection profile from western Portugal used to define subsurface sediment packages from late Pleistocene through recent times. Profile (a) is unannotated while (b) shows the inferred sediment packages, correlated to outcrops about 1 km away.
Chapter 02
1. Figure 2.1 The production of GPR images, beginning with individual traces from one location on the ground, stacked together to produce reflection profiles, with an additional product being amplitude slice-maps of resampled reflection trace amplitudes in individual maps from programmed depths in the ground.
2. Figure 2.2 Some GPR antennae commonly used in geoarchaeological investigations with the 270 MHz energy traveling deepest in the ground (up to 6 m), with the least feature and stratigraphy definition and the 900 MHz with shallow penetration of 1–2 m maximum and higher resolution. The 400 MHz antenna is most useful for medium resolution at depths from 1 to 4 m.
3. Figure 2.3 Models showing the differences in reflectivity from one interface between a clay and sand unit under different water conditions. When both are dry (a), there is no reflected wave at the interface, but when water is added to the system and retained only in the impermeable clay (b), a high-amplitude reflection is produced. When both units are wet (c) the difference in retained water in pore spaces between the two materials still produces a velocity change and therefore a reflection, but one with lower amplitude.
4. Figure 2.4 Resolution of stratigraphic interfaces is a function of radar wavelength and the distance between two interfaces. In this profile created with 900 MHz antenna reflections (upper image) the upper and lower interfaces are resolved, as each produces distinct reflections as can be seen in Trace A. When the distance between the interfaces becomes shorter there is constructive and destructive interference between the waves generated and the lower interface becomes invisible in Trace B with the lower boundary invisible in the reflection profile.
5. Figure 2.5 The interface tested with two different reflection profiles using different frequency antennae. The stratigraphic interface is at the boundary between an upper cobble and gravel unit and an underlying silty sand in southern Arizona. The profiles collected at this exposure are displayed in Figure 2.6.
6. Figure 2.6 The 400 MHz reflection profile is capable of resolving most of the larger clasts in the cobble unit shown in Figure 2.5 and the interface between the two units. The 270 MHz waves passed by the cobbles with no significant reflections generated, and only the interface between the two units was observable in the reflection profile.
7. Figure 2.7 Two 400 MHz reflection profiles collected along the same transect 4 months apart. The data collected in December 2012 when the ground was dry shows high amplitude reflections from the canal base and the sediments on its bank, as the clay units retain water and produce velocity discontinuities. After a large rainstorm in March 2013, the water was preferentially retained in surface soils and along a clay unit at about 60 cm and only those units produced visible reflections, making the canal almost invisible.
8. Figure 2.8 Amplitude slice-maps of the same grid collected during two different years using 400 MHz antennae. When the ground was dry in 2013 the outline of the pit house was visible as well as the central hearth. After much rainfall in 2014 only differentially retained pockets of water produce reflections from the same depth in the ground, demonstrating how important it is to take into account moisture in the ground for GPR interpretation. Both maps were from 400 MHz reflections and generated for the 20–50 cm depth.
9. Figure 2.9 Comparison of two 400 MHz reflection profiles collected in Alaska, one in the summer and one in winter when snow covered frozen ground. The energy spreads out more as it travels in frozen ground and produces a more averaged sequence of reflections from the sediment layers.
10. Figure 2.10 Comparison of two 400 MHz reflection profiles collected on a low topography island along the same transect, on the coast of Georgia. The profile collected at high tide shows energy attenuation in the low ground near sea level at a shallow depth due to salt water infiltration and the resulting radar energy attenuation. At low tide, after a rain storm, the salt water was displaced downward and there is deeper energy penetration and greater resulting bed resolution.
Chapter 03
1. Figure 3.1 A simple way to correlate radar reflections visible in profiles to units of importance is to place the antennae directly on an outcrop and trace them into buried areas of a site. This example is from El Salvador where a volcanic ash unit (TBJ) is buried by many tephra units.
2. Figure 3.2 Known stratigraphic interfaces that are correlated with GPR reflections can be traced in multiple reflection profiles such as this one from El Salvador. Geological units can be defined and studied, and archaeological features within the stratigraphic package identified.
3. Figure 3.3 Reflection profile from El Salvador displaying the TBJ ash at the base of the stratigraphic sequence of interest, with a cross bedded ash flow above it.
4. Figure 3.4 Topographically adjusted GPR reflection profiles can display a dizzying amount of reflections, such as this one, using a 400 MHz antenna from coastal Oregon in cross-bedded aeolian dunes. Within this sediment package a horizontal floor surface was visible, which then was analyzed three dimensionally in a grid of profiles.
5. Figure 3.5 Reflection profile using the 400 MHz antennae showing a horizontal clay floor in sand dune sediment, with many shallow rodent burrows and tree roots producing shallow hyperbolic point-source reflections.
6. Figure 3.6 Many tightly spaced reflection profiles in a grid can be resampled to produce three-dimensional renderings of only selected amplitudes to define archaeological features of interest in the ground. In this case the raised platforms above the floor of a pit house buried in the aeolian dunes (shown in one profile in Figure 3.5) were imaged from coastal Oregon. Moving image of these features is shown in Video 1.
7. Figure 3.7 A very complex reflections profile, in this case a 400 MHz profile, collected on a braided river terrace from southern Arizona. The prehistoric canal produces a vertical “bow tie” reflection in the profile, which was modeled in Figure 3.8 in order to understand its origin. Braided bars produce much less continuous reflections from many cut and fill bed boundaries.
8. Figure 3.8 Two-dimensional models can be produced on the computer to determine what buried archaeological features would look like under certain geological conditions. In this model a “U-shaped” irrigation canal was modeled, displaying the classic vertical “bow tie” reflection almost exactly similar to that visible in the GPR reflection profile displayed in Figure 3.7. This reflection feature was created as a function of the spreading of radar waves from the surface antenna that intersect the opposite edges of the canal, with waves moving at an oblique angle, but being recorded as if they were directly below the antenna.
9. Figure 3.9 Reflection profiles from within a large grid of data in central California collected using 500 MHz antennae. The channel banks, containing archaeological horizons, can be differentiated from geological strata in the profiles as flat high-amplitude planar surfaces. These profiles were sliced digitally in horizontal packages 20 cm (5 ns) thick to produce the amplitude slice-maps in Figure 3.10.
10. Figure 3.10 Displays of amplitudes of reflected waves in 20 cm thick slices generated from 56 reflection profiles collected in a grid. These maps from central California show the banks of a fluvial channel with archaeological floor features on the east edge.
Chapter 04
1. Figure 4.1 Reflection profile using 100 MHz antennae in the Brahmaputra River of Bangladesh displaying two types of river units. The high-flow point bars produced by rapid lateral accretion are well-sorted sand units that are cross-bedded, resting on a basal truncation surface. The lower flow braided bars display many cut and fill features common to complexly braided fluvial systems with alternating poorly sorted sediments.
2. Figure 4.2 Outcrop of a thin fluvial sand sequence resting on an unconformity with Jurassic bedrock, used as a test of GPR profiles shown in Figure 4.3.
3. Figure 4.3 A 400 MHz reflection profile collected adjacent to the outcrop shown in Figure 4.2, showing the small fluvial channels incised into the Jurassic bedrock surface. This profile was collected in order to identify the bank of a channel where late Paleolithic artifacts were discovered nearby.
4. Figure 4.4 Map view of the late Pleistocene fluvial channel system incised into the Jurassic bedrock shown in Figures 4.2 and 4.3. The artifacts in the excavations were placed into this paleoenvironmental context as a way to interpret human behavior in this ancient landscape.
5. Figure 4.5 Reflection profiles using 400 MHz antennae across a fluvial terrace scarp in southern California scarp displaying floodplain sediments and fluvial units. An artifact midden from historic times is visible as many point-source hyperbolas from objects, deposited along the scarp and buried by floodplain sediments.
6. Figure 4.6 Amplitude maps of the fluvial and terrace sediments in southern California showing the terrace edge and the many small high-amplitude reflections from objects in a trash midden deposited on the floodplain along the terrace scarp.
7. Figure 4.7 Photograph of the complex layering within a canal fill unit from southern Arizona.
8. Figure 4.8 Amplitude slice-map from 60 to 100 cm depth showing sediments within irrigation canals with associated fluvial channels that were eroded through the canals during flood periods. Prehistoric agricultural fields were watered by these canals on a river terrace in southern Arizona.
9. Figure 4.9 Reflection profiles showing the complexity of canal and fluvial channel reflections in southern Arizona using 400 MHz antennae. These profiles are placed within the grid in Figure 4.8. It is difficult to differentiate the canals from fluvial channels in this package of materials unless each profile is interpreted individually and the origins of reflections are analyzed.
10. Figure 4.10 A 400 MHz reflection profile showing small alluvial fan channels that incised into the toe of a fan near a site containing adobe melt layers of architecture in southern Arizona.
11. Figure 4.11 Amplitude slice-maps showing the small alluvial fan channels wrapping around adobe mound archaeological site in southern Arizona.
12. Figure 4.12 Cut-stone architecture in an Inca palace that is covered by alluvial fan and debris flow sediments in northern Ecuador.
13. Figure 4.13 A 400 MHz reflection profile in this alluvial fan deposit is barely able to define the small clasts in the cobble and pebble unit. The interface between the units of different clast sizes could be defined only in locations where the radar energy was not scattered by an overlying thick layer of cobbles.
14. Figure 4.14 Amplitude slice-map generated from 400 MHz reflection profiles showing a buried stone structure similar to the one excavated and shown in Figure 4.12. The surrounding alluvial fan and debris flow sediment produced only scattered point-source reflections generated from the larger clasts in the deposits.
15. Figure 4.15 A 400 MHz reflection profile showing point-source reflections from clasts and some low-amplitude alluvial fan strata surrounding an Inca stone structure in northern Ecuador.
Chapter 05
1. Figure 5.1 Correlation of surface and buried soil horizons in an alluvial fill sequence from northern New Mexico. Individual soil horizons each generate high-amplitude reflections in this 400 MHz profile.
2. Figure 5.2 A 900 MHz reflection profile showing reflections produced from alluvial and soil units along a braided river in southern Arizona. The soil horizons produce distinct reflections while the fluvial sands are largely devoid of reflections as they have no interfaces to reflect energy.
3. Figure 5.3 Buried late-Pleistocene soil with distinct E and B horizons within an aeolian sand package from western Portugal. The 270 MHz reflection profile displays lateral variations within this buried soil. The resolution is not high enough to differentiate each of the soil subunits.
4. Figure 5.4 A 50 MHz center reflection profile collected across a peat bog in southwestern Scotland displaying the high-amplitude reflections deposited in lacustrine sediments before the lake and subsequent peat bog was formed. Raised platforms on the margin of the bog, projecting out into the center of the wetland, were work areas and possible habitation structures from late Mesolithic times.
5. Figure 5.5 A 400 MHz reflection profile collected on snow across a small peat bog in the Rocky Mountains, Colorado. This small fen shows a basal clay surface, which was likely deposited in a spring before it filled with organic material.
Chapter 06
1. Figure 6.1 Location on the coast of Israel where 400 MHz reflection profiles were collected in the search for coastal trade facilities.
2. Figure 6.2 A 400 MHz reflection profile showing the kurkar Pleistocene-age bedrock overlain by beach sand that is visible as low-amplitude seaward dipping reflection surfaces.
3. Figure 6.3 A topographically adjusted 400 MHz reflection profile showing wave-cut notches and seaward beach sand produced during transgressive and regressive events on the north coast of Guam.
4. Figure 6.4 Seaward dipping beach strata sitting on an unconformable lower surface from Guam.
5. Figure 6.5 Eroded oolite bedrock along a beach in Key West, Florida, showing the distinct bedrock reflection in this 400 MHz reflection profile, with lower amplitude reflections generated in the beach and aeolian sand.
6. Figure 6.6 Beach units displayed in a 400 MHz reflection profile dip seaward from the eroded bedrock blocks in Key West, Florida.
7. Figure 6.7 Amplitude slice-maps from Key West, Florida, showing the edge of eroded bedrock and many graves in a small basin covered by aeolian sand.
8. Figure 6.8 Tidal flat mudstone overlain by a very thin pebble-sand, encased in aeolian dunes on the west coast of Portugal.
9. Figure 6.9 A topographically adjusted 400 MHz reflection profile displaying the tidal flat unit shown in Figure 6.8 as a high-amplitude planar reflection surface.
10. Figure 6.10 A topographically adjusted 270 MHz reflection profile showing the tidal flat unit pictured in Figure 6.8 being progressively buried by aeolian sand away from the coastal cliffs.
11. Figure 6.11 Low-altitude photo showing the coastal dunes, an interdune low area, and the beach in northern Queensland, Australia. The reflection profile A-A′ is shown in Figure 6.12.
12. Figure 6.12 A topographically adjusted 400 MHz reflection profile that was collected from the beach onto coastal dunes and into an interdune area. A basal bauxite bedrock layer and overlying cross-bedded dunes are visible, which is the sediment matrix for graves.
13. Figure 6.13 A topographically adjusted 400 MHz reflection profile showing the amplitude slices constructed using the profiles in the GPR grid shown in Figure 6.11.
14. Figure 6.14 The 60–90 cm depth amplitude slice-map, the location of which is shown in Figure 6.11, displays the many graves in the dunes. When the slices cut through the interdune areas, the linear amplitude features display bedding variations in the bauxite bedrock.
15. Figure 6.15 Two of the largest Prehistoric shell mounds on the Brazil coast with the location of the GPR grids in the dunes in the foreground.
16. Figure 6.16 Iron oxide cemented layer that could be traced into the sand dunes as a way to correlate reflection horizons in the GPR profiles.
17. Figure 6.17 Topographically corrected 270 MHz reflection profile showing the iron-oxide weathering layer on which the antennas sat in Figure 6.16, covered by recent and older dunes dating to about 4000 BP. The weathering horizon is at the level of the adjacent lagoon, and is likely a ground-water related cemented layer that cross-cuts dunes of many different ages.
18. Figure 6.18 A 270 MHz reflection profile showing dated layers within aeolian quartz sand units. A whale vertebra produced a distinctive point-source reflection hyperbola.
19. Figure 6.19 An intradune reflection surface was generated from shells that were used as a stabilization platform for work and living areas within these aeolian units. This layer is correlative to the horizon where the whale vertebra was uncovered, visible in Figure 6.18.
20. Figure 6.20 Photograph showing the shell paving surface producing the distinct reflection seen in Figure 6.19, which was a prehistoric method of stabilizing these sand dunes.
21. Figure 6.21 Amplitude slice-maps showing the living surface dated to about 4000 BP within the dunes in southern Brazil. The locations of Profiles 63 and 50 in Figures 6.17 and 6.18 are shown in the 40–50 ns slice.
Chapter 07
1. Figure 7.1 The 270 MHz antennae placed in the bottom of a canoe were used to collect reflection profiles as the boat was moved along a rope floating on the lake surface to assure linear transects. This lake at high elevation in the Rocky Mountains of Colorado is dammed by glacial moraine and bounded on one side by landslide rubble.
2. Figure 7.2 A 270 MHz reflection profile collected on the lake shown in Figure 7.1, displaying landslide events on the lake margin and fine-grained sedimentation toward the middle of the lake.
3. Figure 7.3 The 400 MHz antennae were placed in the bottom of this boat and transects were collected at a set rate across the surface of the lake.
4. Figure 7.4 Reflection profile across the lake in Dominican Republic displaying delta deposits on the west and deeper lake sediments on the right. The location of this profile 20 in the lake is shown in Figure 8.5.
5. Figure 7.5 Reflection amplitude map of the sediments in the upper meter of lake bottom units, showing only the highest values obtained from alternating coarse and fine-grained sediments in two delta lobes on the west and northeast. One small high-amplitude area on the north was sampled from only one profile and its origin is unknown.
6. Figure 7.6 Reflection profile collected with 12.5 MHz antennae in a glacial lake in northern British Columbia displaying delta forset beds of a prograding sedimentary sequence lapping on to glacial till.
Chapter 08
1. Figure 8.1 Collecting 400 MHz reflection profiles in the Cherry Creek Canyon Rock Shelter of Colorado.
2. Figure 8.2 Amplitude slice-maps of 400 MHz data at the Cherry Creek Canyon Rock Shelter, Colorado. The excavations and location of profiles in Figures 8.3 and 8.4 are shown, with locations of the excavations, the drip line, and the rear wall of the shelter.
3. Figure 8.3 A 400 MHz reflection profile collected at the Cherry Creek Canyon Rock Shelter displaying high-amplitude planar reflection from the charcoal horizon within the shelter, and a possible discard apron or leveling fill deposit toward the floodplain of the creek to the south. Location of this profile is shown in Figure 8.2.
4. Figure 8.4 A 400 MHz reflection profile showing a number of sediment discard units toward the floodplain to the south, and the bedrock and charcoal living surface within the shelter.
5. Figure 8.5 Excavations at the Gledswood Rock Shelter, Queensland, Australia. The GPR grid was collected in front and to the right of the excavations.
6. Figure 8.6 Bedrock layers and large bedrock blocks are visible as high-amplitude reflections, with prograding sediment layers that filled a basin in front of the shelter over time.
7. Figure 8.7 Depth to bedrock map in front of the Gledswood Rock Shelter, Queensland, Australia.
8. Figure 8.8 Collecting 270 MHz reflection data inside the Lapa do Picareiro cave in western Portugal to test the depth penetration in limestone breccia cave floor sediments.
9. Figure 8.9 A 270 MHz reflection profile showing good energy penetration to about 6 m in the limestone breccia cave sediment at Lapa do Picareiro cave, Portugal.
10. Figure 8.10 Location of the GPR profile testing the thickness of back-fill and the buried landscape in front of the Lapa do Picareiro cave, Portugal.
11. Figure 8.11 Topographically adjusted 270 MHz reflection profile showing the limestone breccia discard material in front of the cave entrance, with the buried bedrock visible as a distinct, almost vertical interface just in front of the entrance.
12. Figure 8.12 Collecting 400 MHz reflection profiles inside the Tuwaty Cave, Ethiopia.
13. Figure 8.13 A 400 MHz reflection profile within the Tuwaty Cave, Ethiopia, showing the attenuating bat guano layer and subtle low-amplitude reflections from hearths within the overlying cave strata.
14. Figure 8.14 Stratigraphy in Tuwaty Cave, Ethiopia, showing dark ash and charcoal horizon from the early occupations with the white phosphorus-rich bat guano layer, overlain by later occupational units.
15. Figure 8.15 Amplitude slice-maps of the cave floor sediments at Tuwaty Cave, Ethiopia.
Chapter 09
1. Figure 9.1 A topographically adjusted 400 MHz reflection profile collected in an attempt to find intact shell midden layers below a disturbed surface soil layer, Latvia.
2. Figure 9.2 Location of one of the 270 MHz reflection profiles from the top of the Muge shell mound, Portugal.
3. Figure 9.3 The sharp contact between the preshell living surface and the overlying shells deposited in the midden. The GPR profiles were tied directly to this excavation in order to correlate GPR reflections to known units.
4. Figure 9.4 A 270 MHz reflection profile collected on the top and flank of the Muge shell midden, Portugal. The pre-shell living surface is horizontal and shell layers deposited on it are visible as moderate amplitude reflections.
5. Figure 9.5 A Pleistocene fluvial channel and the preshell mound living surface on which shells were deposited is overlain by shell layers in this 270 MHz reflection profile from Muge, Portugal.
6. Figure 9.6 Amplitude slice-maps near the surface from an area of monumental architecture at Petra, Jordan, showing the foundations of a Roman temple and other more enigmatic reflections in the deeper slice.
7. Figure 9.7 A 400 MHz reflection profile from Petra, Jordan, which shows the Nabatean living surface prior to a landscape modification that leveled the ground surface to provide a surface for later monumental construction activity. Location of this profile segment is shown in Figure 9.6.
8. Figure 9.8 An eroded adobe mound from a classic period Hohokam multistory dwelling that is today a mixture of eroded clay, some intact floors, and the bases of walls, with many associated artifacts.
9. Figure 9.9 Adobe melt layers adjacent to walls were deposited after the structures were abandoned, producing reflective surfaces for radar energy. The only individual artifacts in these mounds that are reflective are large rocks, such as the grinding stone in the inset picture.
10. Figure 9.10 Four hundred megahertz reflection profile showing high-amplitude planar house floor reflections with an adjacent wall that is non-reflective. Adobe melt layers on top of the floor and adjacent to the walls provide high-amplitude reflections that denote the location of the walls.
11. Figure 9.11 Amplitude slice-maps of a two-room adobe structure showing non-reflective walls and adjacent adobe melt layers within rooms, and on the flanks of structures outside the eroded walls.
12. Figure 9.12 Location of the presbytery and the King Richard III grave, as exposed and published by Buckley et al. (2013), with the location of GPR grid 1. The location of one correlation reflection profile used to directly tie GPR reflections with known stratigraphy is shown in the middle of the church.
13. Figure 9.13 The exposed presbytery foundation and portions of the walls that are composed of sandstone and could be projected into the areas still preserved under the parking lot surface and tied to a GPR profile.
14. Figure 9.14 The darker garden soil is mixed with Medieval architectural rubble overlying the remains of the church where the body of Richard III was found. That unit is overlain by mill waste rubble from nearby industries that disposed of materials starting in the 18th century. A modern cellar intrudes into all these units.
15. Figure 9.15 The three basic stratigraphic units at the Grey Friars church site are visible in this profile with the Medieval level on which the church was built in the 13th century. It is overlain by a post-Medieval rubble layer (sometimes also including the garden soil visible in Figure 9.14) that was deposited or formed after the church was destroyed in 1538. Rubble from a nearby industrial mill was disposed of in this location starting in the 18th century, all capped by the modern parking lot surface.
16. Figure 9.16 A 400 MHz reflection profile used for correlation of the stratigraphy visible in a trench wall with the units displayed in the profile.
17. Figure 9.17 Amplitude slice-maps of GPR grid 1 at Grey Friars Church, Leicester, England, with the annotations of important features visible in profiles and correlated with reflections in map view. The location of three profiles used as illustrations of stratigraphy are shown in the 0–25 cm slice.
18. Figure 9.18 Reflection profile 1.5 m from the west line of GPR grid 1 showing the undulating reflection at the base of the post-Medieval rubble with a few high-amplitude reflections at the depth where Grey Friars architectural features should be found. This area is truncated by a trench a little more than a meter wide, the excavation of which has partially removed the stratigraphy of interest.
19. Figure 9.19 A 400 MHz reflection profile displaying the surface metal drain cover that is directly on top of a modern drainage pipe. The base of the post-Medieval rubble layer overlays a floor on the south side of the profile. The middle of the profile shows truncation by a large excavation, perhaps related to the insertion of the drainage pipe.
20. Figure 9.20 Reflection profile on the eastern side of the GPR grid displaying two areas of incision and removal of the post-Medieval rubble horizon and all other materials stratigraphically below it. A buried piece of concrete with metal reinforcing bars or wire mesh is visible at 12 m.

New Analytical Methods in Earth and Environmental Science

GROUND-PENETRATING RADAR FOR GEOARCHAEOLOGY

About the Author

Acknowledgments