Subsurface Imaging in Archaeology- Geology 436
aka: Archaeological Geophysics
Professor: Steve Sheriff
Syllabus, the ad, project reports, grading papers
Excel tips & exercises (free!)

Here's how it went in 2010:

1/26/2010: Intro to course, and a basic discussion on geophysical targets and methods (magnetic, gravity, electrical, radar). The latter lead to three basic questions: 1) what are you looking for?, 2) what are the physical characteristics?, and 3) what are the material contrasts?, and a flow chart for the experimental process. Introduction to gravity, gravity units, gravity over a buried sphere, operation of the Scintrex CG3 gravity meter, my notes.

2/2/2010: More gravity: buried sphere and horizontal cylinders (spreadsheet example), latitude and elevation corrections, drift curves (24 hour signal) field methods, and an abstract of an archaeological study using gravity. Using CSM's Java applet for modeling the gravity anomaly over a tunnel. Berkeley's gravity page (has great Java applets), an assignment, and my notes.

2/9: Gravity with time; discussion of your bids. Introduction to DC electrical resistivity (Loke's tutorial <-6 megs!, analog model , example). The apparent resistivity of subsurface materials is measured with a number of common arrays used both for profiling and sounding. Coloma (figure, paper). A good paper and my notes.

Assignment: find a professional paper using gravity or DC resistivity pertinent to your interests in archaeology or geology - be prepared to give us a short review of that paper next week (Your presentation outline: authors, problem, experiment, results). We'll use these presentations as a basis for furthering understanding and answering questions.

2/16: Discussion - the papers you read. The Syscal kid specs, depth of investigation and case studies (Coloma (figure, paper), Sandhill, (ppt), Coloma data), and a web report. Modeling and inverting with RES2DMOD and RES2DINV demonstrates:

1. variations of resistivity in the subsurface cause different apparent resistivity values at the surface
2. arrays have variable sensitivity (Wenner, dipole-dipole).

   Here's an assignment using RES2DMOD and RES2DINV for modeling and inverting electrical resistivity profiles.

2/23: Discussion - last week's assignment; accuracy, precision, and resolution. Example magnetic anomaly; the Schonstedt fluxgate magnetometer and Earth's magnetic field (declination, inclination, magnetic elements), D, I in Missoula, magnetic exploration. Self assessment assignment: read this paper on grave detection using resistivity; it should make really good sense at this point.

3/2: Resistivity in the field with the Syscal Kid Switch 24 (see information sheets). We will collect some data for you to interpret. Assignment:

•  Interpret the data we collect today (3/2/2010) and turn in a short report with analysis and inversion - Due next week (3/9). There are two files in the zipped file; one is Wenner, the other dipole-dipole.
• Working in 2-3 small groups, I want you to design and complete either an electrical resistivity or small scale gravity experiment. Follow the field assignment guidelines which includes some ideas on writing your report (3-4 pages not including figures) - Due 3/23 we will discuss/share results in class.

3/9: Your results - now what? Modeling! Magnetics - as good as it gets; flux around a dipole, buried dipole applet (block model). Magnetic minerals and rock magnetism (Butler chapter 2, 3); my notes and something to read:Schmidt (2007).

3/16: Acquisition of magnetization; where we're headed: ISAP note; gridding(figure: 4 methods, data), contouring, and a start to interpreting a magnetic grid using Magpick (source) and upward continuation (my notes).

3/23: Take Home Midterm! Gridding, contouring and a start to interpreting magnetic data using Surfer and Magpick (source); using upward continuation to isolate equivalent sources from various depths.

Lab Exercises in CHC 11 - :

1. make a folder on the desktop with your name on it
2. download the data (epwr.dat, epwr_sparse.dat,epwr_sparser.dat) into your folder
3. start Surfer: grid epwr.dat at 0.5 meter spacing and save it in your folder
4. make a contour map, and overlay a post map of actual data locations. Do the same with the two more sparsely sampled grids. Now, look at and think about your results - what do they tell you about sampling and gridding?
5. experiment enough that you are comfortable with Surfer, maps, and results (grid at different intervals, try different map types)
6. use Magpick and remove and experiment with upward continuation and isolating equivalent sources from various depths.
7. isolate the regional and archaeological residual fields for this Yellowstone grid as best you can.

3/30: Spring Break!

4:/6: More magnetic processing: USGS extensions to Oasis Montaj; decorrugation (MYAP example, gridded data). Intro to Ground Penetrating Radar (Pineview; KF); delectric values, water & velocity, velocity, RDP, wavelength, frequency; (my notes).

Assignment: find a professional paper using magnetics pertinent to your interests in archaeology or geology - be prepared to give us a short review of that paper next week (Your presentation outline: authors, problem, experiment, results). We'll use these presentations as a basis for furthering understanding and answering questions.

4/13: Discussion based on your reading. More GPR: operational wavelengths, reflection coefficient, multiples, metal 'ringing', and diffraction hyperbolas (graves), downloading & measured frequencies: 50mhz, 100mhz, 500mhz; (my notes).

4/20: GPR-GroundVision; GPR in the field: setup and operation. Processing GPR data with Reflex, example.ppt (animate: 1, 2).

Assignment: In one or two groups, compare and contrast 500 MHz and 250 MHz GPR results acquired at Pineview Park as we discussed in class. Follow the field assignment guidelines which includes some ideas on writing your report (3-4 pages not including figures).We will discuss/share results in class on May 4th.

4/27: Processing your GPR data with Reflex.

5/3: Designing a GPR experiment; processing your results & discussion.

5/13: FINAL EXAM: 1:10 - 3:10; Thursday 5/13/2010 - Take Home and in class.

The 2009 course
The 2008 course
The 2007 course

Relevant Links:

Relevant Journals:

Archaeological Prospection - informs archaeologists, environmental scientists, site developers, local authorities and regional environmental agencies about the wide range of scientific techniques available for the study of the near-surface environment.

Journal of Archaeological Science - is aimed at archaeologists and scientists with particular interests in advances in the application of scientific techniques and methodologies to all areas of archaeology.

Near Surface Geophysics - an international journal for the publication of research and development in geophysics applied to the near surface. It puts emphasis on geological, hydrogeological, geotechnical, environmental, engineering, mining, archaeological and other applications of geophysics as well as on physical soil and rock properties.

Geoarchaeology - an interdisciplinary journal which presents the results of original research at the methodological and theoretical interface between archaeology and the geosciences.

SAGEEP - The Environmental and Engineering Geophysical Society (EEGS) convenes the annual Symposium on the Application of Geophysics to Engineering and Environmental Problems (SAGEEP). Proceedings (and the journal) sometimes have archaeolgical papers.

Quick comments on some texts:

Handbook Of Geophysics In Archaeology, A.J. Witten, Equinox Handbooks in Anthropological Archaeology, 2006, 343 p. This is a good, informative and readable introductory text. The organization is excellent as is the breadth of topics and case studies. It should serve well as a textbook. On the downside there are a few errors in the text, among the most glaring is the consistent use of remnant instead of remanent in the magnetics section; likely an editor's mistake rather than the late author's.

Remote Sensing in Archaeology: An Explicitly North American Perspective, J. K. Johnson ed., Univ. Alabama Press, 2006, 319 p.  This is a set of papers resulting from a meeting. All the major methods are presented and reviewed, often in the context of "cultural resource management". The are lots of good case studies but there is insufficient physical background to make this an informative reference book. Never the less, it is a worthwhile read.

Field Geophysics, John Milsom, Wiley, 2003, 3rd edition, 232 p. This book provides the basics of a large spectrum of techniques. It is not specifically archaeological in approach, but it serves as a useful, handy reference and source of facts.

GPR for Archaeology, L. Conyers, Alta Mira Press, 2004, 203 p., This is an excellent book on a specific technique for archaeology. It is well written and all the necessary background is provided in an easily digestible fashion - recommended.

Magnetometry for Archaeologists, 2008, Aspinall, A., Gaffney, C., and Schmidt, A., Alta Mira Press, 208 p. This book gives a very sound background to understanding of magnetics and why there are magnetic anomalies over many archaeological targets. The applications, data processing and visualization are directed mostly at results and conditions in Britain.