Paleoimaging has also been applied in a variety of settings related to field archaeology. A critical issue surrounding the discovery of enclosed spaces such as ancient tombs is that of preexcavation knowledge regarding tomb structure and integrity. The tomb construction is considered an artifact of the external context, that is, the tomb is clearly in association with the mummified remains but not within them or their wrappings. In this purely field application, we describe the utility of paleoimaging in preexcavation tomb analysis scenarios. Standard x-rays may not be able to be applied in this setting due to the need to place the image receptor on the opposite side of the subject, in this case a tomb wall or covering. However, if a small opening exists, endoscopy can "enter" the tomb and provide valuable data regarding the contents of the tomb and tomb construction features, and offer a cursory assessment of the tomb's integrity. These data give the archaeologist an opportunity to plan the excavation effort and prepare the research team for conservation of the artifacts or human remains from within the tomb.
Instrumentation selection is critical, and is based on the objectives at hand. If a large room or vault is being examined, four key features of the instrumentation need to be considered. The first is the length of the instrument. The presumed depth of the room or vault under investigation will dictate the length of the endoscope. Recall that industrial endoscopes can be 60 ft in length. Also, medical colonoscopes can provide adequate length for deep room or vault examination.
The second consideration is that of illumination. Standard endoscope illumination abilities are generally exceeded when used in procedures involving even small,
shallow tombs. It is therefore recommended that a "slave" scope or several fiber-optic light guides be used to enhance the illumination of enclosed tombs. This, of course, requires additional access routes, fiber optics, and light sources. Additional methods of illumination may require creative thinking at the site. Something as simple as a powerful flashlight or flashlights mounted on a rigid pole may suffice provided an access route of that size exists. Figure 8.12 presents a method of providing additional illumination for tomb analysis with a special light guide that bifurcates into two separate light guides.
The third consideration is that of the selection of the proper lens. A near-focus lens would not be able to bring distant objects into clear view. A far-focus lens is required to view the distant reaches of the tomb, room, or vault. An ideal lens would be a stereo lens with one being a far-focus and the other a near-focus lens.
The final major consideration is that of insertion tube support. The fiber-optic instruments, whether industrial or medical, will follow the dependent nature of the open space. It would be important to consider a support system for the advancing scope such as a PVC or other type of pipe with just the tip of the endoscope extruding from the distal end. This method will still allow for a flexible viewing field (Figure 8.13) as the endoscope tip can still be manipulated. External illumination too may be attached to the same support system. If the opening to the tomb, room, or vault is at the top of the space, this adaptation may not be necessary. Small, remote-controlled vehicles can be adapted to carry and therefore direct the advancement of a longer endoscope along the floor on a room under investigation. Additional illumination can be attached to the remote vehicle (Figure 8.14). Additionally, remote video transmitters have also been employed for tomb analysis with reasonable success.
Case study: Postearthquake Tomb Analysis
In 2001, a powerful 8.0 magnitude earthquake struck southern Peru. The quake devastated the city of Moquegua. The tombs of the Chiribaya culture in the Osmore river valley of the Atacama Desert near El Agarrobal, near Ilo, Peru, were impacted by the seismic event. This pre-Columbian culture dates from 900-1350 AD, spanning the middle horizon and the late intermediate time periods. There are literally thousands of such
tombs in this remote river valley. The walls of the valley are essentially huge sandy dunes, which make up the foothills of the Andes. The Chiribaya tombs are located from 1 to 2 m below the desert surface among these sandy slopes. Each tomb typically holds an individual set of remains and associated grave goods. The tomb walls are often constructed of stone with dimensions of about 2 to 3 ft (0.66 to 1.0 m) wide and 3 to 5 ft (1.0 to 1.66 m) in length. The floor is generally packed earth. The depth of the tomb varies from 3 to 4 ft (1.0 to 1.33 m). The tomb may be covered with a mat constructed from reeds, with mud packing on top, then covered with sand. Alternate material used as a tomb cover may be a large capstone covered with sand. The surrounding sand is medium-to-fine grit and shifts with the changing winds. Preearthquake excavations have demonstrated that the Chiribaya tomb design effectively held any shifting sand outside of the tomb space. The earthquake shook the earth so violently in this region that the desert hills of the valley were pocked with depressions in the sand in the location of the subterranean tombs of the Chiribaya, indicating that the surface sands had shifted into the tomb space (Mummy Rescue 2001b).
Even prior to the earthquake, huaqueros, or grave robbers, would routinely find Chiribaya tombs, unwrap the entombed mummies, and take the grave goods and textiles to be sold on the black market. Now, with the tombs marked by depressions in the sand, each tomb was in danger of being ransacked and looted. We devised a plan to employ paleoimaging methodology to determine what impact, if any, the earthquake had on enclosed individual Chiribaya tombs and to assist in the development of plans for rescue excavation and conservation efforts.
Two tombs were examined prior to excavation using an industrial endoscope with a far-focus lens. Since the earthquake occurred unexpectedly, modifications to the endo-scopic instrumentation present needed to be considered. There was no time to acquire battery-powered instrumentation. The endoscopic instrumentation needed to be protected from the blowing sand, and an electric power source needed to be procured. The endo-scopic system was reduced to its smallest components with the instrument light source and camera control unit being fit into a backpack for protection from the environment. Tombs near an access road were selected. A passing taxi was flagged down, complete with a family inside. Researchers first attempted to use a power converter by accessing the taxi's battery through the cigarette lighter. The voltage output proved to be inadequate, and a faint electric overheating smell filled the air. With the failure of this attempt at getting power, assistants drove back to Centro Mallqui, the research facility associated with the Chiribaya project, and retrieved a gasoline-powered generator that did provide the power necessary once the output voltage was reduced by half.
Prior to endoscopic examination, sand was removed down to the level of the tomb roof, exposing only an edge of the roof structure. Two tombs were examined: one having a large flat capstone roof and the other having a roof made of a mud-covered woven reed mat. At the edge of the roof of the tomb with the capstone, a small opening was detected. With the instrumentation protected from the blowing sand, the endoscope was passed through the opening into the tomb. The endoscope image revealed that the tomb had partially filled with sand, burying the mummy inside. Additionally, the endoscope provided an image of a fissure in the tomb, likely produced by the earthquake, running diagonally the full length of the visible wall. This information allowed the project director to devise a plan for excavation that included precautions against cave-in, which would further damage the mummy and associated grave goods, as well as pose a physical risk to the workers.
While the excavation team began work on the initial tomb, the endoscopic operation was moved to the second tomb. Again, a small opening was discovered along the edge of the roof. Internal construction features of the tomb were identified from the endoscope images. The walls were of piled stone, and the roof was a sturdy mat of woven reeds (Figure 8.15), likely obtained from the nearby river valley. The wall construction features suggested that a mud-type mortar had been used to secure the stones of the wall in place (Figure 8.16). The endoscope revealed that sand had indeed shifted into the tomb as a result of the earthquake (Figure 8.17). Using the endoscope to look upward, the construction details of the reed mat roof could be seen clearly (Figure 8.18). Examining the area of the sand slide with the endoscope, a glimpse of buried textile came into the field of view (Figure 8.19), suggesting that a mummy may be present under the sand. After additional survey of the tomb, the endoscope revealed a partially buried mummy whose head was just visible above the encroaching sand. The mummy wore a hat that was identified from the endoscopic image (Figure 8.20) by the project director as being of the Tiahuanacu culture. Using the endoscopic information, excavation and conservation plans were devised.
Figure 8.15 (See color insert following page 12.) Endoscopic image using a far-focus lens showing the internal construction features of this Chiribaya tomb. Note the stone wall and its junction with the reed mat tomb ceiling.
Since access into the tombs was from the top, support for the fiber-optic instrument was not required in this application. A far-focus lens was utilized, which on this particular industrial scope allowed ample light to provide a well-illuminated field of view. The 4 ft length of this endoscope proved to be sufficient for its application to these two Chiribaya tombs.
The field paleoimaging application described in this case demonstrates the utility of paleoimaging in the broader construct of archaeological applications.
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