The geophysical imagery in this library is derived from archaeological projects conducted by Professor Kenneth L. Kvamme. These projects have utilized ground penetrating radar, proton magnetometry, fluxgate gradiometry, electrical resistivity, and electromagnetic conductivity methods. Included in this reference library is a selection of some of the more interesting results...

Note: The quality of many of these images has been degraded for WEB presentation

(To view an image, click on it;
Return to this page by clicking "Back")

The Whistling Elk Subsurface Imaging Project

Battlefield Archaeology!

Magnetometry at Prarie Grove, AR (Civil War)
GPR & Resistivity at Bunker Hill, MA (Revolutionary War)

METHOD, THEORY, AND INSTRUMENTATION

About Archaeological Geophysics Method and Theory
About Geophysical Survey Instruments
About Computer Processing in Archaeological Geophysics

Search by Name and Site Type...

historic prehistoric village prehistoric hunting camp

3D Ranch, KS (19th century)	Bird Creek, KS (Woodland village)	Black Mountain, CO (Paleo-Indian, Folsom)
Bunker Hill, MA (1775 Revolutionary War Battlefield)	Effigy Mounds, IA (Woodland Mounds)	Empuries, Spain (Roman, 1st century)
Menoken, ND (Plains Village, 12th century)	Navan Fort, N. Ireland (Iron Age, 1st century BC)	Old South Cemetery, MA (17th-18th century)
Overland Stage Station, CO (1860s)	Prarie Grove, AR (1862 Civil War Battlefield)	Royall House, MA (18th century)
Sieber Canyon, CO (Archaic)	Sluss Cabin, KS (1870s)	Waraju Distillery, MN (1862 Dakota War)
Ward Village, ND (Plains Village, 16th century)	Whistling Elk, SD (Plains Village, 14th century)

Search by Type of Survey...

Magnetic: Fluxgate Gradiometry & Proton Precession

Bird Creek, KS (Woodland village)	Black Mountain, CO (Paleo-Indian, Folsom)	Effigy Mounds, IA (Woodland Mounds)
Empuries, Spain (Roman, 1st century)	Menoken, ND (Plains Village, 12th century)	Navan Fort, N. Ireland (Iron Age, 1st century BC)
Overland Stage Station, CO (1860s)	Prarie Grove, AR (1862 Civil War Battlefield)	Sieber Canyon, CO (Archaic)
Ward Village, ND (Plains Village, 16th century)	Whistling Elk, SD (Plains Village, 14th century)

Electrical Resistivity

3D Ranch, KS (19th century)	Bunker Hill, MA (1775 Revolutionary War Battlefield)	Effigy Mounds, IA (Woodland Mounds)
Menoken, ND (Plains Village, 12th century)	Overland Stage Station, CO (1860s)	Royall House, MA (18th century)
Sluss Cabin, KS (1870s)	Waraju Distillery, MN (1862 Dakota War)	Ward Village, ND (Plains Village, 16th century)
Whistling Elk, SD (Plains Village, 14th century)

Electromagnetic Conductivity

Whistling Elk, SD (Plains Village, 14th century)

Ground-Penetrating Radar

Bunker Hill, MA (1775 Revolutionary War Battlefield)

Empuries, Spain (Roman, 1st century)

Old South Cemetery, MA (17th-18th century)

Site name: 3D Ranch

Comments: This site represents a pioneer settlement in Kansas that was reportedly a dairy farm. Surface artifacts support an 1860s and later occupation, including a stone-lined well and some foundation blocks near the survey area. The area surveyed may represent the locus of a barn-like structure.

Site name: Bird Creek

Comments: This site, currently under an agricultural field, yields numerous surface artifacts that suggest multiple occupations from the late Archaic through Woodland periods. Ceramics and stone tools are present as are thick lumps of baked clays that might be associated with house remnants. The oval areas might possibly be indications of prehistoric houses. The magnetic extremes suggest large burned areas, possible middens, and hearths.

Site name: Black Mountain

Comments: This site was surveyed during ongoing excavations by the Smithsonian Institution. Three 4 x 4 m excavation pits are clearly indicated by the magnetic extremes associated with grid square corner nails. The small dark linear feature trending southwest-northeast near the top of the image is a filled-in backhoe trench. The igneous bedrock, near the surface on the eastern edge of the survey and the southwestern corner is highly magnetic, yielding a noisy surface. The more central northwest-southeast trending smooth and dark zones contains thicker sediments that mask the more magnetic underlying bedrock. The strong linear feature within this zone (lightly shaded and highly magnetic) indicates a swale or erosional cut. Although some of the localized magnetic highs could be hearths thay are most likely large magnetic rocks.

Site name: Bunker Hill National Monument

Comments: The 20 meter long profiles show possible fortification ditches from the Revolutionary War battle, or subsequent modifications made by the British. Two features about a meter deep are indicated that continue in adjacent transects over a span of at least 26 m. The interior of the fortification would have been to the right in the first figure, which illustrates 6 of the transects.

Type of survey: Resistivity; Instrument: Geoscan Research RM-15; Prospection depth: 1 m; Sampling interval: 0.5 x 0.5 m; Area surveyed: 20 x 20 m; Date of survey: 11/97 and 5/98.

Comments: The first resistivity plan shows clear indications of several linear subsurface features seen in the GPR profiles. They quite possibly represent fortifications from the Revolutionary War battle or subsequent modifications by the British. These results correspond closely with the 6 ground penetrating radar transects shown above. The interior of the fortification would have been to the right. The second figure incorporates later work that illustrates a myriad of features including historic 19th century diagonal walkways, trenches from the park's sprinkler system, the historic fortifications, and linear features that may represent historic pathways.

Site name: Effigy Mounds National Monument

Type of survey: Resistivity; Instrument: Geoscan Research RM-15; Prospection depth: 0.5 & 1 m; 0.5 m; 0.5 m; Sampling interval: 0.5 x 0.5 m; 1 x 0.5 m; 1 x 0.5 m; Area surveyed: 28 x 20 m; 44 x 37 m; 30 x 35 m; Date of survey: 5/99.

Comments: These effigy mounds, managed by the U.S. National Park Service, were surveyed by students of a workshop sponsored by the NPS entitled: "Recent Advances in Archeological Prospection Techniques." The results show the effigy cores to be composed of more resistant soils, with possible building episodes suggested by the clumping of similar values. The first, Little Bear was investigated at 2 depths and indicates discrete sections, particularly in the head and foreleg areas. The second, the Great Bear, also includes two circular mounds. The third, a bird effigy, shows a number of discrete zones, particularly the tail area. The low resistances surrounding each figure are probably due to water pooling and drainage from the mound.

Type of survey: Magnetic gradiometry; Instrument: Geoscan Research FM-36 fluxgate gradiometer; Prospection depth: up to 1.5 m; Sampling interval: 0.5 x 0.125 m; 1 m x 0.25 m; 0.5 x 0.125 m; Area surveyed: 28 x 20 m; 44 x 37 m; 30 x 35 m; Date of survey: 5/99.

Comments:These effigy mounds, managed by the U.S. National Park Service, were surveyed during a workshop sponsored by the NPS entitled: "Recent Advances in Archeological Prospection Techniques." The results show the cores to be composed of more magnetic earths than surrounding soils, probably because nearby topsoils (generally more magnetic) were scooped up to form the mounds (this would also cause the negative magnetic values surrounding each mound). Clumping of similar values may reflect building episodes. The first effigy, Little Bear, shows a more clearly defined "ear" than is seen in the resistance data (above). The large values at the right and bottom are due to NPS steel sign posts. The second effigy, the Great Bear, shows a core of more magnetic earth that is much narrower (about 5 m) than the 8 m width of this effigy (see the corresponding resistance image above). The magnetic data also clearly show 2 ears not seen in the resistance data. The third, a bird effigy, shows the left side of the body and the head to be quite distinct (compared to the resistance data), composed of more magnetic earth.

Site name: Empuries

Comments: The area surveyed is in a level field immediately to the north of the excavated portion of the Roman city (left). A base station recorded diurnal changes in the background magnetic field every 30 seconds (second figure). The diurnally corrected data from the roving unit clearly shows the layout of the Roman street grid (third figure). Many rooms in adjoining areas are indicated as well as a large courtyard. There is a large burned zone near the top center; the arcing washed out area to the right is due to a large iron water tank nearby. The line of bright spots about one-third of the image length from the left are most likely cisterns cut into a sloping escarpment that is also indicated. The city plan shown here corresponds well with the excavated results immediately to the south of this area (right figure).

Type of survey: Ground penetrating radar; Instrument: Geophysical Survey Systems, Inc, SIR-System 3; Antenna frequency: 300MHz; Prospection depth: 3-4 m; Sampling interval: 1 m transects; Area surveyed: about 60 x 40 m; Date of survey: 6/96.

Comments: These 20 m profiles clearly show two walls and a floor about 1.5-2 m below the surface. The three stacked profiles (left) are each separated by one meter. The walls are either Greek or Roman. They were discovered under the parking lot of this national archaeological park, about 30 m to the south of the principal gateway to the Greek settlement. The right transect is one of about 100 obtained at this site.

Site name: Fort Clark Trading Post

Comments: The Fort Clark Trading Post was named after William Clark of the Lewis and Clark expedition. It is located in central North Dakota and was one of several important trading centers on the upper Missouri River. Founded by the American Fur Company and supplied by steamboats from St. Louis, it was sited about 200 m south of the the Mandan village of Mit-tutta-hang-kush in 1830 or 1831. Many first-hand written accounts exist about this site. Its visitors included Prince Maximilian of Wied, and the artists Catlin and Bodmer who left depictions of this trading post in paintings (first figure, by Bodmer). The second image illustrating the magnetic survey results includes three principal zones of interest. First, the outlines of the centrally placed trading post are apparent, with a number of walls and rooms clearly visible. Fort Clark was burned in 1860 and, although its remains were used as a fuel source for steamboat traffic, the firing may have left some of the large magnetic signature seen. A small amount of rubble on the site indicates, however, that foundation stones were composed of a magnetic sandstone and numerous iron artifacts undoubtedly litter the area, contributing to the signal. Although the Missouri River presently flows about a mile from the site, during the 19th century it flowed adjacent to the bluff edge along the bottom of the figure, as seen in Bodmer's depiction. Easy access to the steamboat landing may have been achieved using the draw to the lower left.

The second zone of interest is the Euro-american cemetery, located on the high bluff edge immediately across the draw (south). A number of graves are suggested in the data (detail in right figure), some of which are visible as depressions on the surface.

The third component of the magnetic data is known as Garreau's lodge and enclosure. Garreau was a full-blooded Arikara who took the name of his step-father, an employee of the trading post. The locus of this circular, earth-covered lodge is readily seen, as is its entryway to the east, central hearth, a number of probable sub-floor cache pits (see Huff Village), and a plethora of iron artifacts. Also visible is a faint suggestion of the surrounding enclosure.

Type of survey: Resistivity; Instrument: Geoscan Research RM-15 & MPX-15 (configured as 4 parallel twin); Prospection depth: 0.5 m; Sampling interval: 0.5 x 0.5 m; Area surveyed: 5,600 m²; Dates of survey: 6/00.

Comments: The resistance data (left) perhaps more clearly reveal some of the individual walls of the trading post and multiple rooms are suggested. The data may be compared with extant historical maps, including a sketch prepared by Prince Maximilian in 1833-4 (right). Confusing the picture, however, are a number of linear trenches excavated throughout the site by archaeologists in the 1970s.

Site name: Menoken Village

Comments: This shallow site exhibits clear expressions of multiple prehistoric houses and defensive features in the surface microtopography. The first magnetic image reveals the village's fortification ditch to the east and south (a steep bluff protected the site to the north and west), four bastion loops, historic and prehistoric trails, large burned features interpreted as houses (several verified through excavation), and a number of point anomalies indicative of historic ferrous artifacts. The circular feature in the lower left is an open pit left from a 1930s excavation. The colorized image portrays positive magnetic extremes in red, more clearly defining likely burned features. Of interest are linear alignments of magnetic highs along the interior of the fortification ditch and on 3 of the 4 bastions. While initially interpreted as evidence of a burned palisade, excavations revealed that the magnetic extremes along the interior of the fortification ditch are probably due to a concentration of typically more magnetic A-horizon soils that were removed from the ditch and mounded along the village perimeter. An oval shaped burned house, shown in detail in the third image, may reveal an interior entranceway ramp and a central hearth, features found in one excavated house at the site and at the Flaming Arrow site, some 70 km distant.

Type of survey: Resistivity; Instrument: Geoscan Research RM-15; Prospection depth: 0.5 m; Sampling interval: 0.5 x 0.5 m; Area surveyed: 8100 sq. m; Dates of survey: 7/97 & 5/98.

Comments: While many features seen magnetically are not as clear in the resistance data, except for the open excavation pit, a number of anomalies are revealed that await archaeological testing for identification. The resistance data are particularly useful for delineating what may be prehistoric trails that loop their way around house features, as shown in the second figure. Excavations over one such feature appear to support this interpretation.

Site name: Navan Fort (Emain Macha)

Comments: A number of interesting features are suggested in these data. Most obvious is the circular ring barrow on the far right, visible on the surface and partiallly excavated in the 1960s. The 30 m diameter double ringed enclosure is a new discovery that overlaps and antedates the barrow. The prominent linear feature is a 19th century field boundary and the numerous parallel linear features are associated potato beds. (For further information about this site see Navan Project Page.)

Site name: Old South Cemetery

Comments: This radar profile of 20 m length transects a row of early historic period graves, most of which are unmarked and visible only as shallow surface depressions. With scale marks given at meter intervals across the top of the image, each grave is less than a meter wide. At least 12 indications of graves are visible in this profile, including one at the upper left where a fallen tombstone on the surface gives a clear indication. All grave features are in the top one-third of this image.

Site name: Overland Park Stage Station

Comments: This historic stage stop on the Overland Trail was reportedly burned down with its occupants annihilated by the Arapahoe in the 1860s. It contained a number of buildings, corrals, privies, and the Overland Trail trail itself. The surface contains a littering of historic artifacts from that period, including a number of large wooden beams preserved by the arid climate, and a rain of iron debris. The iron introduces a tremendous amount of noise to the magnetic data, but it also illustrates pattern. In the second image some of this noise has been filtered out. Together, these images suggest possible structures (square corners, linear features, concentrations of iron), an alignment for the Overland Trail (see resistivity below), and two massive iron features.

Type of survey: Resistivity; Instrument: Geoscan Research RM-15; Prospection depth: 0.5 m; Sampling interval: 1 x 0.5 m; Area surveyed: 40 x 40 m; Date of survey: 8/97.

Comments: This historic stage stop on the Overland Trail was reportedly burned down with its personnel anihilated by the Arapahoe in the 1860s. It contained a number of buildings, corrals, privies, and the trail itself. The surface contains a littering of historic artifacts from that period, including a number of large wooden beams preserved by the arid climate, and a rain of iron debris. The raw resistivity suggests a number of highly resistant zones. The second image, created by shadowing the first, more strongly suggests the linear track of the Overland Trail and a linear feature (wall?) along the right one- third of the image that correlates with the large magnetic features given above.

Site name: Prairie Grove Battlefield State Park

Comments: This lesser known Civil War battle included about 20,000 participants on both sides, resulting in about 2,500 casualties. An interesting facet of the battle was the relatively large amount of artillery engaged, with more than 60 cannon. Most of what was shot was made of iron and is therefore readily detected and mapped with magnetic survey methods. This graphic shows a portion of the field where intense shelling by the Federals occurred, some of which was counter-battery fire against a Confederate battery placed to the east of the Borden House. In this area the large number of localized magnetic dipoles suggestive of iron artifacts (represented by small black-white pairs corresponding to north-south magnetic poles) testifies to the accuracy of the Federal fire. More subtle and broader dark and light areas represent soil changes and burned regions probably unrelated to the battle.
NOTE: These results are preliminary and are part of a larger on-going study.

What does the spatial distribution of
an exploded shell look like?
This graphic shows a likely candidate,
to be tested in the future.

Metal Detectorists: Please consider the kinds of information that can be lost if hobbyists continue to excavate metallic artifacts from Civil War battlefields and other sites. For most of the actions that occurred in the Civil War no historic documentation exists. All that can ever be learned can only come through careful study of these remains, including their spatial distributions, using scientific archaeological methods.

Site name: Primeau's Trading Post

Comments: Primeau's Trading Post (or Fort Primeau) was built by Charles Primeau, a disaffected employee of the American Fur Company (also known as the Upper Missouri Outfit) at Fort Clark. Formerly an interpreter at the U.S. Army post at Fort Yates, Primeau constructed his trading post between Fort Clark and the Mandan village of Mit-tutta-hang-kush, a few meters away. The trading post operated until 1861 when the Arikara (who replaced the occupants of the nearby village) moved away. The magnetic mapping clearly illustrates the outlines of this little-known trading post, with a number of walls and rooms clearly visible. The massive magnetic measurements are probably due to a combination of burned features, iron artifacts, and magnetic rock used in its construction.

Site name: Royall House

Comments:The Royall House is a National Historic Landmark. The current property is a small portion of Governor John Winthrop's 600 acre grant obtained from the Crown in 1631. Isaac Royall Sr. brought his family and 20 slaves to the house from Antiqua in 1732, building the mansion and slave quarters. Believed to be Loyalists, they fled to England in 1775. General Stark used the house as his headquarters during the siege of Boston that year. The resistivity data reveal clear indications of landscaped garden features beneath the present paved walkways and trees, indicated in red. A number of highly resistant linear features are shown, probably former brick walkways, that suggest a formal, planned garden. Oval and circular features within also are apparent that may point to the locus of former flower beds and other garden features..

Site name: Sieber Canyon

Comments: Over the past decade about seven hectares of the ridge upon which this survey is located has been part of a project in which approximately 27,000 surface artifacts have been mapped in this desert landscape. The magnetic survey was conducted to locate hearth features by their relatively strong magnetic signatures. Two are suggested in this image. The diffuse magnetic area in the upper left shows dark staining with charcoal in the soil and may indicate a washed out area of burning. The adjoining image depicts the distribution of surface lithic debris in the area surveyed, mapped in an on-going landscape archaeology project (see Landscape Archaeology in Colorado).

Site name: Sluss Cabin

Comments: This pioneer cabin is revealed by a number of cut stone foundation blocks that barely peak through to the surface. These blocks show up as highly resistant in the image revealing a rectangular foundation split into two rooms. One room (left) has a resistant stone floor; the other (right) a less resistant earthen floor (verified with coring). Two possibly linear walkway features show up outside of the cabin. Oral history tells us that the family in this house contracted smallpox. As a result, the cabin was burned down in 1879.

Site name: Waraju Distillery

Comments: The Waraju distillery was built in 1860 as one of the first pioneering industries in New Ulm, by H.A. Subilia. During the Dakota (Sioux) War of August, 1862, it was sacked and burned (along with many other buildings) when the Dakota attacked the settlers of New Ulm. In the 1970s the ruins were leveled and landscaped. Today, all that remains is the original chimney as a monument to that time of tragedy for all involved. The resistivity data clearly reveal that much of the original structure of the Waraju Distillery remains beneath the earth, with many of the principal walls indicated and closely corresponding to the original dimensions of the building.

Site name: Ward

Comments: Within this survey area three large house depressions are clearly visible on the surface that are truncated by a modern walkway (at the top of the image) in this Bismarck city park. The left and middle houses are parallel and cearly visible in this image as dark zones cut into the native earth (white). The axis of the larger right house is angled to the right and partially overlaps into the middle house. Variations in the texture within each house probably reflect interior house features, including post holes, storage and cache pits, and partitions, but also rodent activity and other disturbances to this city park.

Type of survey: Magnetic gradiometry; Instrument: Geoscan Research FM-36 fluxgate gradiometer; Prospection depth: up to 1.5 m; Sampling interval: 0.5 x 0.5 m (digital average of 32 readings); Area surveyed: 20 x 40 m; Date of survey: 7/97.

Comments: The steel rebar pins that hold the walkway's beams in place introduce clear magnetic noise in this area. The left and middle houses are parallel and visible as darker zones in this image. The right-most house, larger, and angled to the right is more amorphous magnetically and overlaps the middle house. The various point anomalies of small size indicate historically introduced pieces of iron in the soil as well as house features including hearths, post-holes, storage and cache pits, and partitions.

Site name: Whistling Elk

Type of survey: Resistivity; Instrument: Geoscan Research RM-15; Prospection depth: 1 m; Sampling interval: 1 m x 0.5 m; Area surveyed: 184 x 110 m; Date of survey: 7/97 & 7/98.

Comments: This site is buried under approximately one meter of alluvium as revealed by limited excavations on the banks of the Missouri River in the late 1970s and recent tests. The resistivity survey was performed by the University of North Dakota Archaeological Field School. The data clearly reveal the complete fortification ditch, 5 bastion loops, numerous earthlodge (house) locations, possible middens, and other features. Of particular importance is the suggestion of an inner fortified village, with perhaps 4 bastion loops and a greater density of houses. The 1970s excavations of burned houses suggested that this village was attacked. This evidence may indicate subsequent reoccupation and reorganization of this village. For additional details, see The Whistling Elk Subsurface Imaging Project.

Type of survey: Conductivity; Instrument: Geonics EM-38; Prospection depth: 1.5 m, peak sensitivity at 0.4 m; Sampling interval: 1 m x 0.5 m; Area surveyed: 170 x 120 m; Date of survey: 7/97 & 7/98.

Comments:That conductivity is the inverse of resistivity is clearly shown in the reversal of the darkness scale assigned to the measurements (compare above) and by a graph of the conductivity and resistance data in two survey grids (second figure). Although obtained much more rapidly, conductivity data represent an average over a larger volume of earth than resistivity, making edges and boundaries somewhat less distinct. Moreover, with a peak sensitiviy at 0.4 m depth, features in the nearby plow zone are much more apparent. In the left figure, two former fields, unused since the 1960s, are indicated by differences in plow mark directions. For additional details, see The Whistling Elk Subsurface Imaging Project.

Type of survey: Magnetic gradiometry; Instrument: Geoscan Research FM-36 fluxgate gradiometer; Prospection depth: up to 1.5 m; Sampling interval: 1 m x 0.25 m; Area surveyed: 170 x 120 m; Date of survey: 7/97 & 7/98.

Comments:The magnetic survey, although appearing noisy at a global scale, reveals faint traces of the bastion shown by the resistivity and conductivity data (see above). Many of the magnetic extremes represent prehistoric burned features, including houses, palisades, and hearths. They also represent historic iron farming artifacts like broken plow parts. At a larger scale, the magnetic data are rich in detail. The second figure shows an Initial Coalescent square house and linear entranceway as revealed by the resistivity data. The correpsonding magnetic data indicate its central hearth, that its walls were burned, and there are even indications of the 4 central support posts which are known to have existed in each quadrant of a house of this period (verified through excavation). For additional details, see The Whistling Elk Subsurface Imaging Project.

Site name: Wuamett Farmstead

Comments: The John O. Wuamett farmstead, established in 1856, is an early pioneering settlement in Steele County. It has been continuously occupied by the Wuamett family until recently. The original farmhouse may be incorporated within the structure currently occupying the site (left). Exploratory geophysics was conducted as part of BRW's Minnesota Farmstead Study with a goal of locating privies, other subsurface features, and structures. In the electrical resistance results (right), many of the large trees and bushes on site yield circular zones of high resistance (black). This survey located several anomalies in the vicinity of a known privy that suggest the presence of multiple additional privies (the magnetic gradiometry data support these findings). The resistance data also yield tantalizing suggestions of possible buried structures.

Type of survey: Magnetic gradiometry; Instrument: Geoscan Research FM-36 fluxgate gradiometer; Prospection depth: up to 1.5 m; Sampling interval: 0.25 x 0.5 m; Area surveyed: 4,000 m²; Date of survey: 10/98.

Comments: With an occupation to contemporary times, this farmyard is loaded with historic and recent iron and steel artifacts and debris that greatly impacted the magnetic survey. Foremost among these were well pipes, a septic tank, water pipes, and various utility lines. Nevertheless, the magnetic data supported several of the more subtle findings indicated by the resistance survey.

BACK TO CAST'S HOME PAGE...
BACK TO ANTHROPOLOGY'S HOME PAGE...
BACK TO OTHER PROJECTS BY KVAMME...