ORIENTATION BOOKLET
GEOPHYSICAL WORKSHOP
MISSION SAN ANTONIO DE PADUA
APRIL 30-MAY 4, 2012
INTRODUCTION
Welcome to the geophysical workshop at Mission San Antonio de Padua,
April 30-May 4, 2012. This five-day workshop will introduce three of the
most useful geophysical methods for archaeologists---magnetic gradient survey,
electrical resistance survey, and ground penetrating radar (GPR).
Approximately one day will be devoted to each method, both in theoretical lectures
and in practical data collection in the field at one of the premier
archaeological sites of the Spanish colonial period in California. Participants
will have ample time for hands-on experience with the equipment. The last
1.5 days may be spent in processing and interpreting the collected data.
Each strategy will be used to extract as much information from the site as
possible in a nondestructive manner. This is not a course in archaeological
excavation or artifact recovery. It does not purport to make anyone an expert
in geophysics, nor is it done for the benefit of a client or agency. It is
designed to make archaeologists, Native American monitors, and land
managing agencies aware of the potential of geophysics to their work and the
importance of working cooperatively with professional geophysicists on such
projects.
The workshop is the outgrowth of a broader program offered annually
for decades by the National Park Service in the Midwest and taught or attended
by some of the same instructors. Dr. Lewis Somers and David Maki of
Geoscan Research/Archaeophysics are experienced in such surveys specifically for
archaeologists in many parts of the world and will instruct on the
geophysical portion of the course. Dr. Robert L. Hoover has been director of the
Mission San Antonio Archaeological Field School for a period of 30 years
(1976-2005). He will introduce the site and aid in the interpretation at data.
In recent years, the trend toward increasingly focused research
designs, the cost and time wasted on random sampling, and rising concerns over the
unnecessary disturbance of primary archaeological resources have resulted
in the more frequent use of various geophysical methods to investigate and
interpret archaeological sites in many parts of the world. Such methods
provide a focused cost and time effective means of collecting information for
the archaeologist, satisfy Native American concerns over site disturbance, and
serve as a valuable planning and protective tool for resource managers.
We sincerely hope that you will all benefit from and enjoy the information
that you will get from this workshop and be able to apply to your own work.
FACILITIES
Participants will be provided with comfortable furnished rooms with
sinks. Towels, washcloths, and soap should be provided by participants.
Hot water and electricity are part of the room facilities, and several sets of
communal showers are available near rest rooms down the hall. We will
take meals communally in the mission refectory at given meal times. we have
arranged a cook to prepare these meals. If you wish additional snacks,
please bring them with you but do not store them in your room to prevent ants.
The mission is surrounded by an army base and is about 30 minutes from the
nearest town, so we try to be self sufficient. Travel across the base to
the mission is subject to strict speed limit requirements by the Federal
Police, and the possession of a driver’s license, vehicle registration, and
proof of insurance. Cell phones are permitted, but reception may not be
possible on site.
HEALTH/SAFETY
Mission San Antonio is located on the interior (eastern) side of the
South Coastal Ranges of California, and thus experiences extreme inland
temperatures in winter and summer. The workshop has been scheduled to take
advantage of the end of the rainy season but before the area begins to warm up
for summer. It is generally a dry area. Be sure to drink adequate water
during the day.
The geophysical aspects of this survey are not particularly dangerous,
as we will not be excavating, getting dusty, or requiring tetanus shots.
However, there are some potential dangers of which you should be aware.
Since the departure of the Franciscans in 2005, the Diocese has forbidden the
mission to arrange to have the grasses burned off the property yearly for
fear of fires. This has resulted in a build up of vegetation, and subsequent
increase in the ground squirrels and their predator rattlesnake population.
The latter have become quite bold in recent years, even reaching the inner
garden and the interior corridors of the dormitory. Watch where you step,
especially when in grassy areas or at night anywhere. Black Widow and Brown
Recluse spiders are also not unknown, but are unlikely to be encountered by
our class. We are attempting to get a commitment from the base dispensary
for emergency treatment, as the nearest hospital is 30 minutes distant in
King City. It is best to wear heavy high boots while working in the field.
The cardinal rule is “Look before you step”! If you have health
limitations or dietary problems, please let Dr. Hoover know about these.
EQUIPMENT
We expect daytime temperatures in the 70s-80s F at this time of year.
Most days should be sunny and mild, but there is a chance of late rains.
In any case, a broad brimmed hat for sun protection is recommended, as are
a pullover or sweatshirt for cool evenings and mornings.
Suggested minimal equipment:
towels, washcloth, soap
socks (heavy)
boots, tennis shoes, slippers
hat (broad brimmed), dark glasses
alarm clock, flashlight
long trousers
sun screen, chap stick, personal grooming items
cameras are welcome
basic lecture equipment: pencils, pens, writing tablets
(other materials will be provided)
You will be a long way from stores. If you don’’t bring it with you, you
may have to do without it. We plan to bring you the most intensive,
useful program possible.
READINGS
Several take-home materials will be distributed to workshop
participants during the program. However, there are two sources that you may wish to
either pruchase yourself for your library or check out of your university
library.
1. Geophysical Surveys in Archaeology: Guidance for Surveyors and
Sponsors by Lewis E. Somers, Michael L. Hargrave, and Janet E Simms (2003 can
be obtained absolutely free as a pdf that can be printed out into a hardcopy
personal version at home.
<http://owww.cecer.army.mil/techreports/Hargrave_ATAGS/Hargrave_ATAGS.pdf>
2. The second is a hardcover textbook with a CD for good graphics.
It is broad in its coverage of the business and CRM aspects of geophysical
survey, in its coverage of survey methods and technology, and in addressing
field methods, targeted anomaly testing, and as contemporary as a book can
be in these evolving times. It addresses the North American archaeologist’s
experience and current practice as geophysical survey continues to be
integrated into and with traditional methods. It is available from Amazon.
<
http://www.amazon.com/qp/product/0817353437/qid=1141053951/st=1-1/ref=sr_1_1/103-6239562-6>. Price $34.00.
CURRENT RESEARCH QUESTIONS
Thirty years of research at various spots at Mission San Antonio have
created a number of questions that might be answered by geophysical survey.
These include the following:
1. This site was first occupied in 1773. A major rebuilding program
took place ca. 1810, resulting in the buildings that you can still see or are
on your maps of the gourds. What was going on in the intervening 37 years?
Where were the earlier churches (1772, 1779) and other early buildings
during that period? The soldiers’ barracks was the only structure with two
successive components recognized by conventional methods so far. Was the
early church located beneath the concrete floor of the present church?
2. What was the capacity of the main mission reservoir? We can
easily get horizontal measurements but have no idea of the depth of the reservoir
without digging test pits through a lot of sterile alluvial fill.
Geophysics may be helpful in determining volumetric measurements.
3. Housing at the mission was prioritized by gender and marital status
(single women first, then married couples, finally single men). The
single men’s dorm was built in 1819 when the population was declining. If the
men lived in traditional hemispherical houses of willow poles and thatch,
where was this traditional village located in the period before 1819? Due to
the presence of hearths, some methods of geophysical survey may be
applicable.
Perhaps additional questions may become apparent during the course of the
workshop. Three heads are better than one, and even more minds at work is
still better. Do not hesitate to bring up ideas in the workshop or informal
discussions.
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