university alabama press remote sensing in archaeology an explicitly north american perspective mar 2006

Typefaces: Garamond and Myriad Designer: Kathy Cummins Library of Congress Cataloging-in-Publication Data Remote sensing in archaeology : an explicitly North American perspective / edite

Remote Sensing

in Archaeology

Remote Sensing

in Archaeology

An Explicitly North American Perspective

Edited by Jay K Johnson

The University of Alabama Press, Tuscaloosa

Published for The Center for Archaeological Research at

the University of Mississippi, the University of Mississippi Geoinformatics Center, and

NASA Earth Science Applications Directorate at the Stennis Space Center

Th e University of Alabama Press

Tuscaloosa, Alabama 35487-0380

All rights reserved

Manufactured in the United States of America

∞

Th e paper on which this book is printed meets the minimum requirements of

American National Standard for Information Science—Permanence of Paper for

Printed Library Materials, ANSI Z39.48–1984

Typefaces: Garamond and Myriad

Designer: Kathy Cummins

Library of Congress Cataloging-in-Publication Data

Remote sensing in archaeology : an explicitly North American perspective / edited by Jay K Johnson

Includes bibliographical references

ISBN-13: 978-0-8173-5343-8 (alk paper)

ISBN-10: 0-8173-5343-7 (alk paper)

1 Archaeology Remote sensing 2 Archaeology North America Remote sensing

3 Indians of North America Antiquities Remote sensing 4 Excavations ogy) North America 5 North America Antiquities Remote sensing I Johnson, Jay K II University of Mississippi Center for Archaeological Research

(Archaeol-CC76.4.R46 2006

930.1028 dc22

2005054863

2 Th e Current and Potential Role of Archaeogeophysics in

Cultural Resource Management in the United States 17

J J Lockhart and Th omas J Green

3 A Cost-Benefi t Analysis of Remote Sensing Application in

Cultural Resource Management Archaeology 33 Jay K Johnson and Bryan S Haley

4 Airborne Remote Sensing and Geospatial Analysis 47 Marco Giardino and Bryan S Haley

Kenneth L Kvamme, Jay K Johnson, and Bryan S Haley

12 Ground Truthing the Results of Geophysical Surveys 269 Michael L Hargrave

Jay K Johnson

CD Containing Color Figures inside back cover

2.1 GIS data layer and example database fi elds for archaeological sites

2.2 GIS data layer and example database fi elds for archaeological projects

2.3 Gradiometer data for a prehistoric feature 22 2.4 Gradiometer data for a nineteenth-century cemetery 23 2.5 Comparison highlighting the advantages of using multiple

technologies 24 2.6 Electrical resistance data and excavation on a prehistoric site in

2.7 Gradiometer data and excavation on a prehistoric site in southwest

Arkansas 25 2.8 Geophysical signatures for an archaeological feature using multiple

technologies 26 2.9 Field methodology and results from a prehistoric site in northeast

Arkansas 27 2.10 Geophysical units of measure 28 2.11 Electrical resistance data and georeferenced 2-×-2-m grid for

2.12 Archaeogeophysical imagery from four technologies with

3.1 Magnetic gradiometer survey of the village portion of the

3.2 Survey of buried prehistoric house remnants at Parchman Place

with electromagnetics, resistance, ground-penetrating radar, and

3.3 Ground truth excavation units superimposed on magnetic

3.4 Trenches superimposed on magnetic gradiometer survey showing

3.5 Surface artifact density plot of the Hollywood site 39 3.6 Magnetic gradiometer survey of the Hollywood site 40 3.7 Magnetic gradiometer survey of the village portion of the

Parchman Place site showing houses, pits, and high-density areas 41

4.6 A 1923 Calvin Brown sketch map of the Hollywood site 67 4.7 Soil Conservation Service photographs of the Hollywood site

4.8 Th e near infrared band from the large-format color infrared

photography of the Hollywood site 69 4.9 Th e near infrared band 6 of imagery obtained with the ATLAS

4.10 Th e thermal infrared band 10 of imagery obtained with the ATLAS

4.11 Th ermal infrared imagery produced by the Agema 570 camera

aboard a helium blimp, Hollywood site 71 5.1 A conductivity survey in progress with the EM38 conductivity meter 80 5.2 A 60-×-60-m view of a “classic” ditch and bank with the EM38 85 5.3 A 40-×-60-m view of an archaeological site showing plow scars 87 5.4 Earth conductivity data uncorrected for “digital lag” 91 5.5 Th e conductivity data of Figure 5.4 corrected for digital lag 91 5.6 Conductivity data collected on zigzag traverses but uncorrected

5.7 Th e same data as in Figure 5.6 with digital lag corrected by

resistivity meter, and data-processing and display unit 110 6.2 Vertical section through uniform soil showing current injection

electrode and voltage measuring electrode, with associated

current fl ow and electric fi eld 114 6.3 A multidepth survey probe confi guration showing current fl ow and

6.4 Th e fi eld confi guration for a typical resistivity survey 115 6.5 A wheeled square array survey system with automated data logging 116 6.6 Schematic representation of zero, low, and high signal-to-noise ratios

with probability distribution functions also shown 121

6.7 Large-area resistivity survey at Army City 123 6.8 Army City, areas of high resistance emphasized 124

6.10 Resistivity survey data from Yucca House 125 6.11 Resistivity survey and magnetic fi eld gradient survey at

6.12 Resistivity survey of prehistoric coastal California house pits 127 6.13 Resistivity survey and magnetic fi eld gradient survey at a

7.1 Th e Geophysical Survey Systems Subsurface Interface Radar (SIR)

7.2 A 400-MHz profi le across a pithouse fl oor; buried water pipes are

visible as refl ection hyperbolas 137 7.3 A 25-MHz antenna, capable of transmitting radar energy to

more than 20 m and of resolving only very large objects of many

7.4 A 900-MHz antenna, which can transmit energy to about 1 m

at most but can resolve features to about 10 cm in diameter 139 7.5 A GPR survey of a ground surface that is not fl at, in which profi les

must be corrected for surface elevation changes in order to produce

a more accurate two-dimensional view of the subsurface 141 7.6 Example of an amplitude slice-map, showing changes in amplitude

in plan view, with each slice representing about 20 cm in the ground 142 7.7 Large trenches dug with backhoes to determine the presence or

absence of archaeological features 146 7.8 A 500-MHz profi le from the Valencia site in Tucson, Arizona,

showing refl ection data obscured by noise 147 7.9 Th e profi le in Figure 7.8 processed to remove the interfering

frequencies, revealing a pithouse fl oor 147 7.10 Amplitude slice-maps produced from the data in Figure 7.9

showing the location of many pithouse fl oors and other

7.11 Amplitude slice-maps from a pithouse site in Utah, revealing a

pithouse fl oor in a diff erent area of the grid than hypothesized from

the concentration of the artifacts 150 7.12 Refl ections from one 500-MHz profi le that crossed the pithouse

fl oor visible in the amplitude slice-maps in Figure 7.11 151 7.13 A 500-MHz refl ection profi le crossing a great kiva 152 7.14 Amplitude slice-maps of the great kiva at Bluff , Utah 152 7.15 Th e convent courtyard at San Marcos Pueblo, New Mexico 153 7.16 GPR profi les of historic graves with intact or partially

7.17 Amplitude slice-map refl ections in a pioneer cemetery in Utah

showing many distinct graves, whose locations are rarely coincident

with the locations of the extant headstones 155 7.18 A three-dimensional rendering of the highest amplitudes in the

same grid of data used to make the slices in Figure 7.6, imaging

8.1 Magnetic enhancement of soils at the Cahokia Mounds site 163 8.2 Unit susceptibility profi le from a basal platform joining two mounds

8.4 Th e Bartington MS2D sensor 168 8.5 Th e prototype down-hole magnetic susceptibility logger in operation 169 8.6 Field evaluation of the Bartington MS2H 171

8.8 Profi le across the Grand Plaza at the Cahokia Mounds site showing

natural sediments and overlying cultural material, with data gained

from soil magnetic studies, soil chemical tests, and core descriptions 174 8.9 Magnetic susceptibility survey of a prehistoric structure in

8.10 Down-hole magnetic susceptibility results at the Rustad site 184 8.11 Down-hole magnetic susceptibility studies at the Canning site 185 8.12 Base map showing the earthworks at Hopeton and the locations

of three trenches excavated in 2001 and 2002 186 8.13 Magnetic susceptibility contour map of the north face of Trench 3

8.14 Magnetic susceptibility values along a single elevation line on

the north face of Trench 3 at the Hopeton Earthworks compared

with cesium gradiometer data collected at this location 188 8.15 Application of magnetic techniques to the identifi cation of areas

of stability, erosion, and sedimentation on a Mississippian period

8.16 Mound erosion processes for platform and conical mounds 191 8.17 Topographic and soil magnetic data for Mound 36, Cahokia 192 8.18 Topographic and soil magnetic data for Mound 62, Cahokia 193 8.19 A plot of ARM/χ versus distance from Core A (mound summit),

8.20 Core locations and topographic profi le showing the asymmetrical

8.21 A plot of ARM/χ versus distance from the crest of Mound 56

showing a bimodal version of the pattern observed for Mound 36 196

9.1 Principal magnetometers used in archaeology: Geometrics-856

proton precession magnetometer, Geometrics-858 cesium vapor

magnetometer, Geoscan Research FM36 fl uxgate gradiometer 213 9.2 Increasing detail and quality of anomaly defi nition as a result of

greater sample densities over a pair of burned houses at the

Menoken Village State Historic Site 215 9.3 Magnetometer anomalies created by intensive fi ring 216 9.4 Magnetometer anomalies created by fi red artifacts 217 9.5 Positive magnetometer anomalies caused by accumulations of topsoil

associated with constructed features 218 9.6 Negative magnetometer anomalies produced by the removal of

9.7 Signifi cant magnetometer anomalies introduced by imported stone 220 9.8 Strong magnetometer anomalies produced by iron and steel artifacts 221 9.9 A magnetic survey in the vicinity of granite boulders showing large-

magnitude dipolar anomalies stemming from remanent magnetism 225 9.10 Massive anomalies caused by large iron or steel bodies on a site 226 9.11 Dipolar anomalies representing steel-wire pin fl ags 227 9.12 Total loss of data in one segment of a survey as a result of keys

9.13 Dipolar anomalies found to be clusters of steel bottle caps and

9.14 Th e spatial organization of the Fort Clark Trading Post and its environs

at the Fort Clark State Historic Site as revealed by magnetometry 230 10.1 Magnetometry data from Primeau’s Trading Post at the Fort Clark State

Historic Site, North Dakota, showing eff ect of a de-spiking algorithm 237 10.2 Magnetometry data from an early Archaic occupation at the

Wallace Bottom site, Arkansas, showing use of Fourier methods

10.3 A complete magnetic processing sequence: raw data illustrating drift

and heading errors; data after “zeroing” the transects; data after application

of a “de-staggering” algorithm; data after removal of the gait defect through

Fourier methods; data after low pass fi ltering; data after interpolation 240 10.4 Grid imbalances in total fi eld data gathered by a proton precession

magnetometer at the Roman city of Empuriés 243 10.5 Magnetometry data from Double Ditch State Historic Site,

North Dakota, subjected to contrast manipulation 245 10.6 Typical modes of graphic display illustrated with magnetometry

data from the Great Bear effi gy at Effi gy Mounds National

10.7 Magnetometry data from Huff Village State Historic Site,

North Dakota, with an interpreted map 248 11.1 Geophysical surveys at Whistling Elk village: resistivity, conductivity,

11.2 Geophysical mappings of circular earthlodge(s) at the Mandan/Arikara

village in the Fort Clark State Historic Site: resistivity, GPR time slice,

11.3 Th e brick foundation of the Mount Comfort Church as revealed

by resistivity, GPR, and magnetic gradiometry 256 11.4 Multidimensional geophysics at Army City: resistivity, conductivity,

magnetic gradiometry, magnetic susceptibility, and GPR, and RGB

11.5 Gradiometer image of the Hollywood Mounds site 260 11.6 Photographic imagery of the Hollywood Mounds site 261 11.7 Airborne digital imagery of the Hollywood Mounds 261 11.8 Magnetic gradient image of prehistoric house remains reclassifi ed

11.9 Airborne imagery used in reclassifi cation 263 11.10 Original pixel classifi cation and discriminant function results 264 12.1 Results of electrical resistivity survey at the Crying Hawk site 283 12.2 Th e Grossmann site: results of a magnetic fi eld gradient survey

12.3 Results of mechanized stripping, resistance survey, and soil cores

12.4 Electrical resistance map of the Army City site, Fort Riley, Kansas 292 12.5 Panoramic photograph of Army City, ca 1918 294 12.6 Trench excavated to ground truth a fortifi cation ditch at the

12.7 Magnetic map of Fort Clark Trading Post, North Dakota 297 12.8 Map showing magnetic foundation stones documented in a block of

contiguous test units at Fort Clark Trading Post 298 12.9 GPR map of Ellis Cemetery showing the location of gravestones 299 13.1 Magnetic gradient and magnetic susceptibility images of the

Walford site showing pit feature locations 307 13.2 A portion of the resistance imagery from the Presidio de Santa Rosa

showing the utility of a fi lter 309 13.3 Magnetic gradient image of the Confederate cemetery on campus

at the University of Mississippi 310

3.1 Test excavation simulation results 42 3.2 Cost simulation of traditional vs remote sensing–based data recovery 43 4.1 Th ermal inertia values for common materials 53 5.1 Resistivity and conductivity of diff erent soil types 83 5.2 Typical data set produced from data logger for processing 95 11.1 Standardized canonical discriminant function coeffi cients for

11.2 Classifi cation results for house location analysis 265 12.1 Usefulness of ground truthing techniques at the sites discussed

Th is is my third edited volume Each time I fi nish one, I vow not to do another And then the opportunity comes by and it’s too good to pass up In this case, the qual-ity of the contributions and the timeliness of the collection persuaded me Also, the prospect of working with such a distinguished and agreeable group of chapter authors made the project attractive I thank them all I met most of the contributors to this book when I attended my fi rst National Park Service workshop on remote sensing and archaeology at Chillicothe, Ohio, in 2001 Th ese annual events are sponsored by the Midwest Archeological Center and organized by Steve De Vore I thank the NPS and Steve for the opportunity to learn so much in such a short period of time Although Berle Clay is a regular instructor at the NPS workshops, I have known him just about

as long as I have been working in the Southeast: a long time However, he deserves cial mention in that he introduced me to the potential of geophysical remote sensing when he showed up at the Hollywood site in 1997 with a conductivity meter It was

spe-an impressive demonstration; test pits in six of the eight possible structures revealed in the resultant imagery came down on house fl oors I also met Marco Giardino at the Hollywood site and, as outlined in Chapter 1, he was a coconspirator in organizing the regional workshop in Biloxi that led to this volume Not only did he help organize it, but he also provided NASA funding for both the workshop and the follow-up meet-ing in New Orleans at which the contributors got together to work out the details

of the volume Funding for the production of the volume as well as the workshop was pro vided by the University of Mississippi Geoinformatics Center, a NASA-funded initiative under the direction of Greg Easson at Ole Miss Th is volume is the seventh time that I have worked with Kathy Cummins as copy editor and typesetter As always,

it has been a pleasure I literally could not have done it without her Finally, I thank Bryan Haley, my coauthor on two of the chapters in this volume, a “fi rst generation” graduate of the remote sensing and archaeology focus of our graduate program, my research associate, and the man who keeps it all working while I attend to administra-tive and academic matters

Remote Sensing

in Archaeology

Jay K Johnson

Th is book began in a conversation between Marco Giardino and me at the bar in Fitzgerald’s Casino during the summer of 2001 Th e bar top was embedded with video gaming screens and we had worked out a system whereby it took us nearly two hours to lose $10.00 playing blackjack All that time we were supplied with “free” beer Before going any further, I should mitigate this revelation by pointing out that Fitzgerald’s Hotel was the fi eld headquarters for the Ole Miss fi eld school that year We were work-ing on the Hollywood Mounds, a large, late prehistoric ceremonial center at which geophysical survey techniques, particularly gradiometry and conductivity, have proven remarkably eff ective Marco was working with us, wrestling with the much more dif-

fi cult job of getting informative results from ground-penetrating radar (GPR) in the clays and silts of the Mississippi alluvial valley

We were bemoaning the lack of application of these techniques in Southeastern archaeology in general and cultural resource management (CRM) archaeology in par-ticular As the chapters that follow will demonstrate, remote sensing, especially the geophysical techniques, has reached the point where it can make a substantial con-tribution to the dirt archaeology of the Southeast However you frame the argument, whether in terms of refi ning the research design or of cost eff ectiveness, on most sites, the application of remote sensing early on in the fi eldwork will lead to better results However, on some sites you might as well leave the instruments in the truck One of the goals of this volume is to help CRM administrators integrate remote sensing into their data-recovery programs in an informed way

But, back to Fitzgerald’s We decided that many of the archaeologists working in the South were not aware of the remarkable advances in remote sensing applications that have occurred during the past 10 years and that what was needed was a work-shop on remote sensing applications in archaeology Marco secured funds through his offi ce, NASA’s Earth Science Applications Directorate at Stennis Space Center; I found additional support from the University of Mississippi Geoinformatics Center; and a workshop was planned for the Wednesday preceding the annual meeting of the Southeastern Archaeological Conference (SEAC), which was held in Biloxi, Missis-sippi, in 2002.

I got on the phone to my friends in remote sensing and in a short time bled the impressive list of instructors represented in the following chapters Th at was followed by the much more demanding task of locating and inviting the state ar-chaeologists, state historic preservation offi cers, and chief highway archaeologists or their representatives from the 11 states that are traditionally represented in the SEAC membership We planned to begin the workshop with a fi eld trip to Tullis-Toledano Manor, a historic site in Biloxi, where there would be demonstrations of the various instruments Th e afternoon would be devoted to presentations on the several major remote sensing techniques appropriate to archaeology A reception was planned for the evening, during which we would talk about all that we had done that day

assem-Th e workshop was a success Many of the participants expressed an interest in plying the techniques and, in fact, several were from state agencies that were already using some of the instruments Th e presentations were all quite good So good, in fact, that we decided to follow up with a one-day workshop just for the instructors in which

ap-we would work on preparing a handbook on remote sensing applications for CRM archaeologists We met in the French Quarter in New Orleans at the Royal Sonesta Hotel and spent another very successful day talking about the focus of the publication

Th en came the hard part: fi nding the time to fulfi ll the commitments we had made and actually writing the following chapters

Although the workshop was presented to archaeologists working in the Southeast, the instructors work throughout North America and the volume refl ects this broader perspective For this and other reasons, I am pleased with the results, but, of course, the fi nal judgment will be up to the readers I would like to address one fundamental question, however Was such a volume needed? Th ere are, after all, several very good summaries of remote sensing applications in archaeology (Aitken 1961; Bevan 1998; Clark 1996; Gaff ney and Gater 2003; Scollar et al 1990), most of which have the same emphasis on geophysics that is evident in the following pages However, there are

at least three reasons to add one more book to this list

In the fi rst place, we are riding the crest of a technology that is advancing on a daily basis For members of my generation, who did their dissertation research using punch cards, this is particularly evident But the rate of advance is accelerating Th is

is especially true in remote sensing, in which large amounts of data must be processed

in complex ways and the output is most useful in a graphic format Driven by tions with much more economic impact than archaeology, computer graphics, mem-ory, and processing time are improving exponentially If you doubt that, violate the cardinal rule of buying a PC, and see what you could have gotten for the same money

applica-a month lapplica-ater Scollapplica-ar applica-and his coapplica-authors (1990) published one of the most hensive reviews of remote sensing in archaeology to date Certainly it contains more formulas than any other publication on the subject And it is still an important source of fundamental concepts However, it came out more than a decade ago and the discussions of computer hardware and graphic presentation are useful only

compre-as a benchmark of where we’ve been You can eff ectively date a publication by looking

“Time Team,” that features applications in archaeology Why is it that the random person on the street in London is likely to be able to discuss the relative merits of using a magnetometer rather than GPR, while many North American archaeologists are not sure what these instruments do in the fi rst place? Part of the answer lies in the nature of the archaeology Almost any discussion of the archaeological application of aerial photography will have a long section on crop marks, which appear to be par-ticularly useful in discovering Roman villas and Bronze Age fortresses, site types that are uncommon in North America Sites that predate the Neolithic are not regularly featured in discussions of remote sensing in Europe, for obvious reasons—the traces left behind are far less structured and much more diffi cult to detect using remote sensing techniques Th is is, of course, the case with most of the prehistoric record in North America

Finally, although most of the archaeologists who attended the workshop in Biloxi came away convinced that remote sensing will make a major contribution to the ar-chaeology that they administer, many also expressed frustration; the successful appli-cation of the techniques relies on a great deal of expertise in archaeology, geophysics, digital image processing, and soils When the right instrument is used on the right kind

of archaeological deposit buried in the right kind of soil, the results are often lar However, there is an unfortunate history of inappropriate applications in which a substantial amount of money was spent with no results A general overview of remote sensing techniques that will guide archaeologists in the selection and application of instruments is badly needed at this stage in the development of the fi eld Th at is the major goal of this book

spectacu-Th e heart of the book is the applications chapters (Chapters 4 through 9) Each author was asked to cover the following topics:

Overview of the technique

Discussion of basic principles

A brief history of its application in archaeology

A summary of currently available and generally used instrumentation

A description of the typical fi eld strategy

Some idea of the kinds of data-processing software that

are most likely to be useful

Examples of successful applications

Case studies, many of which are drawn from the chapter author’s

(or authors’) own research

Guidelines for application

When to use which combination of instruments

of the New Orleans meeting was to work together on the details of this chapter No such comprehensive guide to the successful application of remote sensing techniques is currently available, but we judge that the time is right

So, now you have some insight into the origin and justifi cation of this volume, but before concluding this introduction, I would like to do a few more things First, there is the not-so-trivial question of what exactly we mean by “remote sensing.” Th ere was some discussion of this topic at the meeting of contributors in New Orleans In fact, most of the geophysical techniques that have provided spectacular results in ar-chaeology are hardly remote Some remote sensing instruments—gradiometers and conductivity meters—are generally carried back and forth across the site 10–20 cm above the ground GPR systems must make contact with the surface of the soil in order for the signal to propagate, and conductivity meters can be dragged along the surface Resistivity readings are taken by inserting probes into the soil, and some susceptibility applications, as being pioneered by Rinita Dalan (Chapter 8, this volume), require that the sensor be inserted into a borehole Compared with satellite and airborne sensors, these are obviously a diff erent class of readings However, geophysical techniques are still used to measure phenomena that are remote from the sensor and cannot be seen otherwise It is just a matter of scale, as suggested by Payson Sheets (1991) in an article entitled “‘Very-to-Barely’ Remote Sensing of Prehistoric Features…,” in which he re-

ports the results of the application of instruments ranging from airborne multispectral scanners to GPR.

More important, there is a fundamental similarity in the way that satellite, borne, and geophysical data are processed and evaluated For example, the question

air-of resolution is an important fi rst consideration in all cases Th e smaller the unit of observation—pixel size in remote sensing terms—the more likely you are to fi nd small features and the prettier the picture However, the fi ner the resolution, the more ex-pensive the data in terms of acquisition, storage, and processing If you are looking for broad-scale patterns, it is often unnecessary to spend the money on high-resolution images It may even be a detriment For example, in GPR, the higher the frequency of the antenna, the smaller the object that can be detected However, many of the refl ec-tions that are recorded in GPR are irrelevant to understanding the cultural deposits at a site Th e usual goal of a radar survey in archaeology is to detect buried structures, seen

as major refl ections that continue across several transects Much of the data recovered

by using a high-frequency antenna is noise

Many of the data-processing techniques used in geophysical analysis were oped for the analysis of satellite data A high pass fi lter is a high pass fi lter whether it is being used on digital data acquired by a sensor orbiting hundreds of kilometers above the earth or on data acquired by a gradiometer carried back and forth across the site at

devel-a distdevel-ance of devel-a few centimeters from the surfdevel-ace And thdevel-at fi lter cdevel-an be devel-applied using software written specifi cally for magnetic gradient data, such as Geoplot, or it can be applied using one of several programs written specifi cally for more traditional remote sensing analysis; ERDAS Imagine, for example

Another conceptual advantage to the more inclusive defi nition of remote sensing

is that many of the standard procedures of satellite image analysis hold tremendous potential in archaeology For example, anyone who deals with geophysical data uses the basic concepts developed in geographic information systems (GIS) analysis, and it

is clear that the integration of data recovered by more than one instrument is likely to increase our understanding of the structure of an archaeological site But, as Chapter

11 on multiple instrument applications illustrates, we are just beginning to make use

of the powerful tools that are available to integrate multiple kinds of spatial data

As I have indicated, this is hardly the fi rst book on remote sensing and archaeology

As the instructions to the chapter authors indicate, it is not meant to be a sive or detailed introduction For those of you who want to learn more or are interested

comprehen-in the remarkable pace of development comprehen-in this area of archaeological research, there are several options

Th e most comprehensive early overview of geophysical survey techniques in chaeology is more than 40 years old but still contains valuable information Aitken (1961) reviews a fi eld of inquiry that was hardly more than 10 years old at the time

ar-of his writing As the title ar-of the book, Physics and Archaeology, suggests, his topic is

broader than just remote sensing, and there are chapters on radiocarbon dating and trace element analysis However, there are also chapters on magnetic detection and

resistivity surveying Beyond the wonder the book inspires at the determination it took

to use instruments that were slow and imprecise by today’s standards and the time it took to record and plot the values by hand, it is also a bit humbling to realize how little

we have progressed in the basic understanding of the characteristics of the cal record that infl uence the utility of these techniques Aitken (1961:1) also makes the distinction between fi nding archaeological sites and exploring those sites once they are found and notes that diff erent methods and instruments are useful in each case For example, he includes a brief discussion of aerial photography in his chapter on site discovery, while the chapters on magnetics and resistivity deal mostly with mapping features within sites

archaeologi-Th e National Park Service has played a lead role in the introduction of remote sensing techniques in North American archaeology In fact, the fi rst publication with goals that are similar to ours came out in 1977 under the title Remote Sensing: A Hand- book for Archeologists and Cultural Resource Managers (Lyons and Avery 1977) Ten

supplements were published, the last coming out in 1985 Most deal with regional applications with an emphasis on airborne and satellite sensors However, Supplement

3 (Lyons et al 1980) is an extensive bibliography, containing several entries relating to geophysical techniques along with the more numerous citations dealing with airborne and satellite sensors Supplement 2 (Morain and Budge 1978) presents a discussion

of instrumentation and contains the only discussion of traditional geophysical niques Th is short section is introduced with a defi nition of remote sensing that in-cludes geophysical techniques and makes the observation that “in archaeology, we take considerable interest in buried structures and artifacts, objects that are not visible to the eye and quite probably not directly detectable using space or airborne sensors Th is

tech-is the area in which ground based remote sensing plays a vital role” (Morain and Budge 1978:24) A summary discussion of magnetometry, resistivity, and radar concludes this section of the supplement

Th e fi rst comprehensive, generally accessible overview of the application of physical techniques in North American archaeology was written by John Weymouth (1986) and published in the Advances in Archaeological Method and Th eory series He

geo-concentrates on the exploration of site structure since “these tools are too costly and time consuming to be used for site discovery and identifi cation” (Weymouth 1986:312) Resistivity, one of the oldest methods to be used in archaeology, is discussed in some detail It is interesting to note that, although Weymouth illustrates several diff erent probe arrays and discusses the disadvantages in using the Wenner array, his examples are drawn from Wenner array data Because of changes in available instrumentation, this confi guration has been almost completely replaced by the twin array Likewise, although he discusses magnetic gradiometers, a relatively new instrument at the time, most of his examples of magnetic data were recorded using a single instrument and

a separate base-station instrument to record and adjust for changes in the magnetic

fi eld throughout the day Finally, electromagnetic conductivity meters are discussed but no case studies are presented Th e late 1980s was a period of rapid development

in instrumentation and, in some ways, this article is located at a watershed Th e use of dot density maps to display survey results is another expression of the time at which it was written Still, the potential of the techniques is clearly expressed and a good deal of insight into the strengths and weaknesses of the various instruments is presented.NASA became active in remote sensing applications in archaeology during the 1980s and, not surprisingly, there was an emphasis on digital remote data, mostly derived from satellite-based instruments (Behrens and Sever 1991; Sever and Wise-man 1985) Limp (1989) provides a useful summary of the use of digital multispectral imagery in archaeology as of 1989 Th e primary source of these data at that time was sensors mounted on satellites, most of which had a resolution of 20 m or more SPOT,

a French sensor, was launched in 1986 and provided 10-m data Airborne sensors could do much better, achieving a resolution of 2 m or less It is not surprising that,

of the 68 studies summarized in the report (Limp 1989:table 23), all deal with either site discovery, environmental delineation, or predictive modeling Only one published study mentioned in the text (O’Brien et al 1982) was successful in detecting within-site cultural features Limp (1989:54) does conclude, however, that “multispectral im-agery also has great potential for within-site studies,” particularly with the increasing availability of high-resolution sensors

It is interesting, therefore, that Scollar et al (1990), in one of the most sive books on remote sensing in archaeology yet to be published, spend three chapters

comprehen-on the use of aerial photography and another comprehen-on airborne thermography including cussion of sophisticated computer-based image transformations but make no mention

dis-of multispectral sensors Th is may be partially the result of the tremendous success of the application of aerial photography in Europe (e.g., Wilson 1987) in contrast with its limited use in North America (e.g., Deuel 1969) Th e treatment of resistivity and mag-netic and electromagnetic prospection in Scollar and colleagues’ book contains a great deal of detail, often expressed in equations Although it is not light reading, it is an essential reference for anyone wanting to truly master the fundamentals of geophysical applications in archaeology Th is probably accounts for the fact that it rarely shows up

on any of the on-line rare-book dealer sites As mentioned above, most of the sions of graphic techniques and nearly all of the details on computer software and hardware have been rendered obsolete by the remarkable advancements in this area.Because it was expensive, hard to fi nd, and tended to be technical, the Scollar text is not nearly as well known as another overview of geophysical survey applications in archae-ology published in Great Britain in the same year, that by Clark (1990) Like Scollar, Clark was in on the early growth of geophysical applications in archaeology, having had a part

discus-in the mid-1950s discus-in developdiscus-ing one of the fi rst resistivity meters designed especially for archaeologists Th e book begins with a thorough review of the history of geophysical prospection in Europe, with an emphasis on Great Britain Clark (1996:7) notes his conscious decision to avoid the use of equations, and his presentation relies heavily on several rather persuasive images A second edition, brought out in 1996, was updated with a 17-page supplement that documents some of the notable advances in instru-

mentation and processing that took place during the early 1990s Clark wrote his sertation on resistivity and, not surprisingly, the chapter covering that technique is the longest in the book Magnetometry and magnetic susceptibility get their own chapters, but electromagnetic conductivity is treated as a subheading in the resistivity chapter and GPR is included in a chapter titled “Other Methods.” Th is is an improvement over treatment of the topic by Scollar and his coauthors (1990:575–584), who devote 10 pages (and 12 equations) to GPR In fact, this coverage refl ects the relative importance

dis-of the various techniques at the time the books were written

GPR is the one technique that is best known by the public and general cal community Th e fi rst thing people ask for when they contact me about a survey

archaeologi-is GPR However, it archaeologi-is also the most diffi cult of the geophysical instruments to use

in terms of data processing It is appropriate, therefore, that there is a book devoted entirely to the archaeological application of GPR (Conyers and Goodman 1997) Th e timing of its publication is also appropriate because Conyers and Goodman are able to document a major breakthrough in GPR survey, one in which they played a part Th e standard output of a GPR survey is a profi le along the line of travel of the antenna Th is profi le shows a series of refl ections, most often as horizontal bands that are defl ected when the instrument passes over a buried object that has suffi cient contrast with the soil matrix in which it is buried An experienced operator can interpret these profi les, but for the rest of us they are similar to Rorschach tests And, since most of the features that archaeologists are looking for are easiest to recognize in plan view, the profi les must

be considered in aggregate GPR became much more useful to archaeologists with the development of processing techniques that allow several parallel profi les to be stacked side by side and extrapolated into a data cube Horizontal slices can then be generated and broad horizontal patterns discovered As a result of this advance, GPR has become one of the principal tools in geophysical survey in archaeology over the past decade

Th e National Park Service, particularly the Midwest offi ce, continued to sor applications of remote sensing to archaeological research problems throughout the 1980s and 1990s Two general overview monographs (Bevan 1998; Heimmer and De Vore 1995) as well as a valuable series of annual workshops in remote sensing and archaeology have resulted Th e week-long workshops are typically held at a major ar-chaeological site (My graduate students and I attended our fi rst one in 2001 focusing

spon-on the Hopewell earthworks at Chillicothe, Ohio.) Most of the cspon-ontributors to this volume are regular instructors at the workshops Th ese workshops are excellent intro-ductions to the fi eld and refl ect a shift in emphasis that has occurred in remote sensing applications in archaeology since the handbook by Lyons and Avery (1977) was pub-lished by the National Park Service Th e primary emphasis at these workshops is geo-physics with some discussion of aerial photography but, at least at recent workshops, little on digital airborne or satellite data

Like the earlier publication (Lyons and Avery 1977), there is an explicit emphasis

on CRM applications in Heimmer’s (1992; reissued as Heimmer and De Vore 1995) review of geophysical applications to archaeological research Th is monograph is a con-

cise discussion of the several diff erent techniques that are most commonly used in archaeology written by a person trained in geophysics Appendices include a glossary,

a selected bibliography, and a list of providers of equipment and contract surveyors

Th e fi nal appendix includes a limited selection of images produced by geophysical surveys of archaeological sites Unfortunately, the discussion of techniques presented

in the body of the text is completely divorced from the archaeological examples and the bibliography of archaeological applications Although the publication is useful, it

is diffi cult to get a feel for the relative merits of the instruments and the way they have been applied on archaeological sites

Bevan’s (1998) monograph goes a long way toward correcting this problem Bevan has been one of the major practitioners of archaeological geophysics since the mid-1970s, and his Geophysical Exploration for Archaeology: An Introduction to Geophysical Exploration refl ects this depth of experience In addition, Bevan has a talent for ex-

plaining the physics so that archaeologists can understand them Th e only shortcoming

of this work is that, as a special publication of the Midwest Archeological Center, it has had limited distribution Also, Bevan is somewhat conservative when it comes to graphic presentation

In contrast, the latest booklength overview of geophysics and archaeology (Gaff ney and Gater 2003) takes full advantage of advances in computer graphics and image analysis that have become available to the archaeologist More than a hundred mostly gray-scale images and two dozen color plates off er compelling arguments for the im-portance of geophysical techniques in archaeological research Alternative methods of data transformation are discussed and illustrated along with side-by-side comparisons

-of diff erent ways to present the data Gradiometer images -of entire Roman villages look like town maps, and resistance plots showing detailed fl oor plans of medieval buildings leave little doubt that the long tradition of geophysical research and development in British archaeology has paid off

Beyond the importance of understanding and appreciating the development of archaeological geophysics in Great Britain, there are other important issues that are raised by Gaff ney and Gater Th e fi rst is the contrast between the application of the techniques here and in England Although CRM archaeologists are beginning to take advantage of geophysical techniques in the United States, a major portion of the re-search and most of the publication take place in an academic setting Th e reverse is true

in England where, of the estimated 450 geophysical surveys performed on logical projects per year in that country, the vast majority are done by “independent groups” (the British equivalent of CRM fi rms) under contract with developers (Gaff -ney and Gater 2003:fi g 3)

archaeo-A second issue is raised by this (Gaff ney and Gater 2003:22) and an earlier review

of archaeological geophysics in England (Clark 1996:8) As a result of changes in the guidelines for planning and development that took place in Great Britain in the early 1990s, archaeological geophysics was expanded to become a site-discovery technique

In this, there is another strong contrast between Great Britain and the United States,

where there are almost no examples in which geophysical surveys have been used to

fi nd sites In North American archaeology these techniques have largely been used

to conduct what Gaff ney and Gater (2003:88) call site assessment and investigation

Th is may be a refl ection of the academic emphasis of archaeological geophysics in the United States It may also be a result of the diff erence in the archaeological record be-tween the two countries

Gaff ney and Gater (2003:120) begin their chapter on case studies dealing with historic sites with the observation that for the Paleolithic the dispersed and ephemeral nature of the surviving archaeology means there is little remaining that the techniques can detect For the Mesolithic, even though longer lived sites with good evidence for

pre-fi res exist, pre-fi nding them provides the sort of challenge that most geophysicists would rather pass by Likewise, Scollar et al (1990:4) note that “with the invention of agri-culture at the beginning of the neolithic period, man began to perturb this natural sequence [pedogenesis] for the fi rst time … Before agriculture, tents or small sheds were sometimes constructed, but their remains are very diffi cult to spot.”

Th e problem for North American CRM archaeologists is that a large portion of the archaeological sites that they deal with fall into the category that European archaeolo-gists fi nd diffi cult to detect and explore using geophysical techniques Th is is partially because in most of the United States, intensive agriculture began little more than 1,000 years ago Th ere is, however, another factor When Bryan Haley and I give papers on the results of our geophysical research in the Southeast, we usually show pictures of large, late Mississippian sites on which buried mounds, burned house remains, plazas, and other features are clearly evident in the images Th ese are exactly the kinds of sites that will be avoided if at all possible by CRM planners because of the large budgets needed to excavate them Th erefore, if we are to make the case for including geophysi-cal survey as a regular part of the CRM planning process in the United States, those

of us who do the work must devote more energy to the small hunting camps and horticultural villages that predate the major settlements of the agricultural periods and predominate in the archaeological record As some of the case studies discussed in the following chapters illustrate, understanding these sites will almost certainly require the application of multiple instruments, the results from which must be evaluated in conjunction with the ground truth excavations

Before I close this literature review with such a decidedly European bias, I should tell you that although there are fewer people doing archaeological geophysics in the United States than in Europe and they have been doing it for a shorter period of time, there are several signs that they are catching up Ken Kvamme, one of the best of the

“second generation” practitioners of archaeological geophysics in the United States, has written a couple of recent review articles (Kvamme 2003a, 2003b) in which he discusses the application of the techniques in terms of their practical and theoretical benefi t to New World archaeology and argues persuasively for a central role for archaeological geophysics in CRM archaeology (Kvamme 2003a:452–453) He also maintains the North American Data Base of Archaeological Geophysics website, whose creation was

funded by the National Center for Preservation Technology and Training, a National Park Service program Th is website (http://www.cast.uark.edu/nadag/) contains links

to numerous other websites dealing with archaeology and remote sensing, a hensive bibliography, a current list of practitioners, and a project database containing survey results from most of the contributors in this volume Th is would be an excellent starting point for anyone interested in learning more about archaeological geophysics

compre-in North America

Th ere is one fi nal measure of the boomtown growth of the application of remote sensing, particularly geophysics, in North American archaeology While I was fi nishing this introduction, I received a December 2003 monograph authored by Lew Somers and Michael Hargrave entitled Geophysical Surveys in Archaeology: Guidance for Survey- ors and Sponsors, published by the Construction Engineering Research Laboratory of

the U.S Army Corps of Engineers Th e primary focus of this monograph is a decision support software called ATAGS (Automated Tool for Archaeo-Geophysical Survey), which was written to help CRM archaeologists and novice geophysical researchers in designing survey protocol Th e user inputs several diff erent site parameters, soils, integ-rity, and anticipated kinds of features, and the program makes recommendations about sampling interval and fi eld time for resistivity and gradiometer surveys An annotated bibliography of major publications on archaeological geophysics along with discus-sions of fi eld and data-processing procedures and a few case studies are also provided.Clearly, there is a growing awareness of the potential contribution of remote sens-ing to North American archaeology in general and CRM archaeology in particular Not only can it be justifi ed in terms of cost eff ectiveness on large, complex sites (Johnson and Haley, Chapter 3, this volume) but, as Jami Lockhart and Tom Green demonstrate

in Chapter 2, geophysical survey fulfi lls the specifi c requirements of CRM laws and guidelines in a way that other methods of site assessment cannot match

Although airborne and satellite-based remote sensing has been overshadowed in archaeological applications in recent years, geological, environmental, and surveillance applications have created a market that has resulted in better spectral and spatial reso-lution at a much reduced price In many cases, the prehistoric patterns of interest are spread out across the landscape in such a way that airborne imagery is the only reason-able approach Marco Giardino and Bryan Haley review past and current applications

in Chapter 4 In addition, in some instances it has been possible to extend geophysical results by using them as a training set for a multivariate classifi cation of airborne imag-ery with much broader coverage (see Johnson and Haley’s discussion in Chapter 11).Chapters 5, 6, 7, and 9 cover the four major instruments used in archaeologi-cal geophysics in North America Because we deal with diff erent kinds of sites, elec-tromagnetic conductivity instruments may be more important in the United States than in Europe, and Berle Clay’s chapter does a good job of pointing out the various conditions under which they are likely to be useful Resistivity, on the other hand, is much more important in British applications than in North America However, as Lew Somers demonstrates, it is an important technique that should certainly be con-

sidered Larry Conyers’s chapter on GPR deals with data processing a bit more than those of the other contributors because GPR data demand more and greatly diff erent techniques in order for them to be accessible to the average archaeologist Chapter 8, written by Rinita Dalan, covers magnetic susceptibility, a technique that is not much used in archaeological geophysics in this country, but should be Kvamme’s chapter on magnetometry makes it clear why this is one of the primary tools for the investigation

of large prehistoric and historic sites

Other than the good food and good company, the New Orleans workshop was valuable in that we all got together and made decisions about what we wanted this book to contain Chapters 10 and 11 are direct results of that meeting Because data processing is so important in making sense out of remotely sensed data, we decided to devote a separate chapter to it All participants were invited to contribute but it is fi t-ting that Kvamme ended up writing it since he is always pushing the limits of the data through processing and presentation

We also decided to add a chapter on multiple instrument applications Th ere are very few sites that would not be easier to understand if two or more instruments were used Not only do the diff erent instruments detect diff erent things, but often they see the same things diff erently Moreover, statistical techniques, many of which have been borrowed from the analysis of satellite-based sensor data, are making “data fusion” more a reality and less a buzz word

One of the common complaints made by people who do archaeological ics is that they do the survey and someone else does the ground truth (excavations) using the imagery produced by the remote sensors but failing to get back to the sur-veyors with the results Th is is an unfortunate result of the specialization required to

geophys-be able to aff ord and understand these instruments and it has slowed the growth of archaeological geophysics as a science However, as Mike Hargrave demonstrates in his chapter on ground truth excavation techniques (Chapter 12), the feedback that should occur between those who obtain the imagery and those who do the excava-tions will allow a much better use of the geophysical survey results and a more com-prehensive data recovery

Th e fi nal chapter is a compendium of the previous chapters with a special emphasis

on when remote sensing is likely to be useful and which instruments to use in specifi c situations In this it follows a long tradition within the literature, often expressed in tabular form (David 1995) It is a tradition that will continue as the techniques and instruments improve For example, the fi rst time we tried GPR at the Hollywood site (Johnson et al 2000) we couldn’t even detect a steel culvert under one of the fi eld roads Th is conforms with the general wisdom that GPR is a poor choice of techniques

in fi ne-grained soils Since various kinds of clays are the major constituent of the sissippi alluvial valley in northwestern Mississippi, we held little hope for the technique

Mis-in our research area However, a newer Mis-instrument and better processMis-ing techniques allowed a solid Master’s thesis to be written on the use of GPR at the Hollywood Mounds (Peukert 2002)

And that is one of the major lessons to be learned from this or any review of the use of remote sensing in archaeology As the number and kind of applications grow, the results are becoming more and more sophisticated Th ere can be little doubt that

in fi ve or fewer years a second edition of this volume will need to be written Th e good news is that we have made plans to do just that

References Cited

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Bevan, B W

1998 Geophysical Exploration for Archaeology: An Introduction to Geophysical Exploration

Special Report No 1 U.S Department of the Interior, National Park Service, Midwest Archeological Center, Lincoln, Nebraska

Conyers, L B., and D Goodman

1997 Ground-Penetrating Radar: An Introduction for Archaeologists Altamira, Walnut

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1995 Geophysical Survey in Archaeological Field Evaluation Ancient Monuments

Laboratory, English Heritage Society, London

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1969 Flights into Yesterday St Martin’s Press, New York.

Gaff ney, C., and J Gater

2003 Revealing the Buried Past: Geophysics for Archaeologists Tempus, Gloucestershire,

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Heimmer, D H

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National Park Service, Rocky Mountain Regional Offi ce, Division of Partnerships and Outreach, Interagency Archeological Services, Denver.

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1995 Near-Surface, High Resolution Geophysical Methods for Cultural Resource Management and Archeological Investigations, rev ed U.S Department of the Interior,

National Park Service, Rocky Mountain Regional Offi ce, Division of Partnerships and Outreach, Interagency Archeological Services, Denver

Johnson, J K., R Stallings, N Ross-Stallings, R B Clay, and V S Jones

2000 Remote Sensing and Ground Truth at the Hollywood Mounds Site in Tunica County, Mississippi Center for Archaeological Research, University of Mississippi, Oxford

Submitted to the Mississippi Department of Archives and History

Kvamme, K L

2003a Geophysical Surveys as Landscape Archaeology American Antiquity 68(3):435–458.

2003b Multidimensional Prospecting in North American Great Plains Village Sites

Archaeological Prospection 10:131–142.

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Series 34 Arkansas Archeological Survey, Fayetteville

Lyons, T R., and T E Avery

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Cultural Resources Management Division, National Park Service, Washington, D.C

Lyons, T R., R K Hitchcock, and W H Wills

1980 Remote Sensing, Aerial Anthropological Perspectives: A Bibliography of Remote Sensing

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The Current and Potential Role of Archaeogeophysics in Cultural Resource Manage- ment in the United States

J J Lockhart and Thomas J Green

Th e value of geophysical surveys in archaeological applications is increasingly ognized as project results are disseminated at conferences and in publications within the United States As a result, use of geophysical techniques is becoming more com-mon—particularly in research applications—as archaeologists come to realize the util-ity and effi ciency of these powerful tools Th e eff ectiveness of archaeogeophysics has not, however, been fully acknowledged in the laws, regulations, and standards that guide cultural resource management practices and excavation strategies

rec-Archaeogeophysical technologies and specifi c applications are described in detail

in subsequent chapters of this volume As a point of reference, however, the fi eld of archaeogeophysics encompasses a range of noninvasive methods for delineation and analysis of subsurface archaeological and cultural features (Clark 1996; Conyers and Goodman 1997; Kvamme 2001) Generally speaking, archaeological sites are the prod-uct of cultural and natural formation processes (Schiff er 1987) Sites are altered by an-thropogenic activities and the natural accumulation of sediments Soils are physically and chemically changed over time, and the archaeological record is transformed both

spatially and quantitatively Th ese site formation processes produce a three-dimensional archaeological matrix or volume composed of topographic and physical properties such as soil texture, soil compaction, stratigraphy, biogenic and biochemical components, diff er-ential moisture retention, thermal alteration (burning), and artifact composition Ar-chaeogeophysical technologies provide the capability to measure the variable strengths and locations of physical properties that make up the archaeological record.

Th e term cultural resource management (CRM), as used in this study, refers to the

body of laws, standards, and practices that guide the management of prehistoric and historic properties within the context of modern research, preservation, and land plan-ning A broader defi nition of CRM also includes aspects of artifact curation and re-lated document management (King 1998), but this chapter relates specifi cally to how the practice of archaeogeophysics is relevant to archaeological resource management in land planning activities and the preservation of archaeological properties

In the United States, federal and state laws require the consideration of historic properties in project planning and land management activities and provide for the protection of archaeological sites on public lands Th e overarching law is the National Historic Preservation Act of 1966 Section 106 of that act states:

Th e head of any Federal agency having direct or indirect jurisdiction

over a proposed Federal or federally assisted undertaking in any State

and the head of any Federal department or independent agency having

authority to license any undertaking shall, prior to the expenditure of

any Federal funds on the undertaking or prior to the issuance of any

license, as the case may be, take into account the eff ect of the

undertak-ing on any district, site, buildundertak-ing, structure, or object that is included in

or eligible for inclusion in the National Register Th e head of any such

Federal agency shall aff ord the Advisory Council on Historic

Preserva-tion established under Title II of this Act a reasonable opportunity to

comment with regard to such undertaking.

In short, Section 106 requires federally assisted agencies to “take into account” the

eff ects of their projects on historic properties—including archaeological sites—and give the Advisory Council on Historic Preservation the opportunity to comment on them.Section 110 of the same act further requires federal agencies involved in land plan-ning and development activities to implement affi rmative management programs designed specifi cally for the preservation of historic properties In addition to Section 110, the Archaeological and Historic Preservation Act of 1974 requires federal agencies to document historic and archaeological properties that may be impacted by land management activities In subsequent legislation, the Archaeologi-cal Resource Protection Act of 1979 expressly prohibits the unlawful destruction of archaeological sites located on federal land Th e more recent Native American Graves Protection and Repatriation Act (NAGPRA) of 1990 requires federal agencies to con-sult with Native American tribes prior to the excavation of Native American graves

on federal land Taken as a whole, this body of law and associated regulations governs archaeological research methods and preservation issues associated with federally sanc-

tioned land management projects in order to mitigate adverse aff ects to archaeological sites Th ere are also state laws that govern archaeological research conducted on private and nonfederal public lands.

In a 1983 response to the laws outlined above, the U.S Department of the Interior and the National Park Service published Th e Secretary of the Interior’s Standards and Guidelines for Federal Historic Preservation Programs Pursuant to the National Historic Preservation Act (1983) Th is document provides general advice concerning “best prac-tices” for compliance with historic property laws and regulations Standards and Guide- lines includes information about preservation planning, site identifi cation, evaluation,

registration, documentation, and professional qualifi cations Because the Secretary of the Interior’s publication is intended to provide general guidance for preservation proj-ects across the United States and its territories, many states also have developed more detailed standards and guidelines for archaeological research that address specifi c re-gional environmental and cultural situations

In order to assess the extent to which a land-use project might impact the cultural resources of an area, archaeological sites and other historic properties must fi rst be identifi ed and evaluated One of the fi rst steps in this process is to determine whether sites have been previously located in the project area and whether archaeological sur-veys have been conducted To facilitate the initial identifi cation of archaeological sites

in a given project area, many states and federal agencies have developed computerized inventories of archaeological and historic properties (Figure 2.1) Integrated geo graphic information systems (GIS) and database management systems, such as the examples from Arkansas (Hilliard and Riggs 1986), contain attributes relating to site location, site size, National Register status, site features and function, and much more

Archaeological site databases provide cultural resource managers and other land planners information about where sites are and what they are Th ese statewide data-bases are continually updated, thereby making up an essential part of an effi cient CRM process However, the potential for discovering previously unrecorded archaeological sites within a project area is also an important consideration Consequently, it is like-wise useful to know where and how people have looked for sites—even if none were identifi ed Figure 2.2 shows a statewide GIS data layer for archaeological projects and surveys Many of the areas shown have been systematically surveyed for Section 106 compliance Attribute databases for archaeological surveys contain information about who did the survey, how they did the survey, and what was found

Th e dense distribution of known and as yet undiscovered archaeological sites in many parts of the United States—coupled with modern land-use trends, archaeologi-cal research, and CRM legal requirements—has driven the development of more pow-erful tools to eff ectively manage and protect cultural resources while accommodating construction, agriculture, and other changing land-use patterns One of these emerg-ing tools in American archaeology is archaeogeophysical survey technology

Geophysical technologies provide the capability to map and analyze subsurface archaeological features (Figure 2.3) Archaeogeophysical surveys are nondestructive by