A scene from the Detectorists, a BBC comedy that follows the lives of small-town hobbyists using metal detectors to hunt for buried treasure, illustrates important aspects of the future of treasure hunting. In the last episode of season one, the team is searching a local farm for the ship-burial site of King Sexred of the East Saxons. As they have searched the area all summer long without results, they decide to call off the project and begin to walk off the field. The camera then goes into an aerial view and shows the outline of a buried ship, indicated by lighter-colored grass, while the detectorists walk right past it. Just missed it!
What can we learn about the future of treasure hunting (as well as archeology) from this scene? Having eyes in the skies is a tremendous advantage while searching for treasure, so researchers will begin with aerial imaging and thus save a lot of boot leather and spadework. What about the discolored vegetation showing the outline of the buried ship?
While the director may have been taking artistic license in the scene by making the invisible visible, the fact remains that buried structures, or more accurately the materials of buried structures, can indeed give us clues to their location. How?
Subsurface materials can have an effect on the coloration of the surface vegetation above them. This technique was used by researchers to recently discover what is believed to be the second North American Viking settlement on the southwest coast of Newfoundland. Archaeologist Dr. Sarah Parcak began her research by using DigitalGlobe’s WorldView-3 satellite. Using the near-infrared spectrum, the satellite detected buried walls which, when excavated, yielded artifacts consistent with other known Viking settlements. So, satellite imagery, especially multi-spectral imagery, can be a boon to treasure hunters and archaeologists alike. With Google’s purchase of SkyBox Imaging, the free satellite imagery from Google Earth will only get better.
Descending out of Earth orbit, we find that aerial imaging, via manned or unmanned platforms, can help treasure hunters. In addition to multi-spectral imaging, lidar is helpful in finding subsurface structures by providing detailed DTMs, which can be processed through image analysis to locate areas of interest. Thermal imaging is yet another tool that we covered in the first part of this series. If South African treasure hunters are to be believed, metallic objects can be found as deep as six feet underground using the technique described in this issue of Pangaea.
Aeromagnetic surveying, using magnetometers, can find magnetic metals associated with treasures. I recently spoke with a member of a local UAS firm who noted that his firm’s craft were using magnetometers to search for gold in the northern Canadian provinces. (I asked for details but he quickly clammed up, such is the secretive world of gold and treasure hunting.)
Still another tool being developed is UAS-based ground penetrating radar (GPR). We’ve all seen ground-based GPR units used to discover subsurface structures, voids, and soil disturbances: all key indicators of buried treasure. Now UAS-based GPR is being developed; the military, for example, is already testing it to locate land mines. The Schiebel Camcopter S-100 unmanned helicopter is an example of one such platform being developed. UAS are ideal for this as they can cover much more territory than ground-based units and can fly much closer to the ground than manned aircraft, thus improving the effectiveness of the GPR. Helicopters are preferred due to their ability to handle the heavy GPR units. It’s not much of a stretch to see UAS-based GPR employed in the near future for treasure hunting.
It seems clear that in the future treasure hunters and archeologists will be relying more on remote sensing and less on shovels; it’s faster and can cover more ground in less time. Archeological digs that took decades are being accomplished in a few years thanks to these tools, and they’re only getting better, faster, and cheaper!