Ben,

I would strongly recommend not spending money on a GPR survey before doing a
thorough metal detection survey.  GPR is expensive and, if not used in
conjunction with another subsurface technique such as magnetometry or soils
resistivity may prove to be almost useless.  

Suggest gridding the site in 20 ft or similar grid units and going over each
unit at least twice using experienced detectorists with good equipment.  The
frequency of hits within each grid unit can be converted to a gradient map
that will show the relative distribution of metal material. This can be used
as a guide for further work whether it be a GPR survey or testing.  

I would not excavate hits from deeper that the plow zone (roughly 12 inches)
so as not to disturb any intact buried deposits. 

Good luck

Jim  

James J. D'Angelo, RPA. Ph.D.
President & Site Archaeologist



The Fort Daniel Foundation, Inc.
Phone: 770-513-1576
Cell: 404-580-2079
Email: [log in to unmask]
Visit us at: www.thefortdanielfoundation.org

 
 

 
 
 
 


-----Original Message-----
From: HISTORICAL ARCHAEOLOGY [mailto:[log in to unmask]] On Behalf Of Benjamin
Carter
Sent: Monday, September 13, 2010 9:36 PM
To: [log in to unmask]
Subject: Renting GPR or Magnetometer.

  All,

I am in the process of studying a historic site (c. 1750) in eastern PA. 
Based upon historic documents we have a good idea of the location of the 
site and part of it falls within an open field. I have been over the 
site multiple times and there are very few hints as to where within that 
field the site may be. There may have been one structure that had a 
stone foundation, but that may have been removed historically. There 
were probably approximately 35-50 other 'houses' that did not have stone 
foundations. I want to try an relocate these structures based upon their 
post-holes, trenches and artifacts, especially nails. At least one of 
the structures was burned so the nails should be distributed around that 
foundation. These has been some historic disturbance at the site, but I 
don't believe that structures were buried, but they were likely plowed.

I am trying to figure out the best way to relocate the site more 
precisely. I would love to use either GPR or Magnetometry, but the 
equipment can be extremely pricey and I have a fairly limited budget. 
There are also a myriad of variations that I could potentially use and I 
am having a difficult time determining which would be the best.

Does anyone have suggestions? Are there inexpensive GPR, etc. equipment 
that I could rent? I am considering using metal detectors in the 
organized fashion laid out in previous posts to this list serve.  That 
seems more affordable and I may know a couple of people who have them 
and, hopefully, would help out. Unfortunately, that doesn't give me a 
great map like you can get from GPR. It is also limited because it gives 
little information about the item that has been detected.

I greatly appreciate any and all assistance.

Cheers,
Ben Carter