| AOR Archaeology Online Resources |
| Underwater Archaeology has become an area with increasing gusto! Exploring historical sites and locations underwater gives a glimpse of the past that can often not be found in other locations. These often include sunken ships and wrecks, but it can also encompass cities and sites where artifacts can be found within the water at varying depths. The greater the depth, the more likely it has never been disturbed (as the ability to reach suchs depths has only fairly recently become available for the average person with SCUBA), but the more difficult to maintain and excavate. Here you will find a variety of information related to this area of Archaeology! |
| Underwater Archaeology |
| "Discover, Explore, and Learn from the Past!" |
| Here you can browse a variety of topics related to underwater archaeology. |
| Introduction |
| Links |
| Discovering Sites |
 |
| News |
| To discover sites underwater, various techniques are used. These can include detection equipment, such as using a magnetoscope which is linked to a navigational system and sounder which feed information to a computer. Usually when detecting, one is hoping to detect a ferrous (iron or metal) mass which causes an anomaly in the Earth's magnetic field. Magnetoscopic probes can be towed by a ship which aid in the location of ancient wrecks and sites. Research into old ship logs and documentary sources of various sources are also utilized to locate lost wrecks and underwater sites. |
| Exploring Sites |
| Underwater sites can be accessed only by using specialized equipment. This often includes SCUBA equipment, ROVs, Remote Operated Vehicles, or various other submersibles. Various ROV's and submersibles can sustain immense pressure at great depths and explore sites that humans are unable to explore in standard SCUBA equipment. Sites that are deeper than about 60 meters can be explored with traditional diving techniques, but documentation is usually elementary at best with short examinations due to the depth and dangerous conditions. Sometimes a different gas mixture, or mixed gasses, can be utilized for increased bottom time at these depths. Decompression is always recommended at these depths...for those without a SCUBA background, this refers to your body off-gassing Nitrogen and other gasses that build up within your body as you are diving in deeper locations. No-decompression limits are usually around 30 feet. If a diver, or in this case deep diving underwater archaeologist, comes up without decompression stops along the way, it is very possible that he/she will cause the gasses within to "bubble" and come out of solution...which is, simply put, very bad! This is how various organs can be damaged, bubbles get to the heart or under the skin and cause trouble, and so on. |
| Learning/Training |
| Learning the techniques that are used by Underwater Archaeologists take special training. Sometimes ships are used as a base for study. An example would be the Archeonaute which belongs to the French Government that is used to train archaeologists. The Archeonaute has a decompression chamber, pneumatic launchers, diving equipment, underwater wireless equipment, photography items, photographic laboratory, compressors, drill, various pumps, underwater propellers, metal detectors, hydraulic crane, and other helpful items aboard. |
| Technique |
| Once a site is located, the excavation and exploration begins. First a site must be cleaned, especially if it is covered in undergrowth. A "water lance" or "galeazzi lancet" can be used to remove sediment buildup. They discharge the sediment toward the rear. Once a site is clear, then a reference grid is installed which aids in calculations and registering all of the data. An orthogonal quadratic grid is often used, made of nylon cables or PVC tubing creating grid squares in 2x2 or 4x4 meters. Once the site is layed out, exploration of the wreck or site begins. This often involves the use of powerful "vacuum cleaners." The air suctorial and water suctorial are examples. When artifacts are found, they are directly numbered and a number is placed in a photograph next to the artifact(s). After this is done, the artifacts are then removed and taken into storage. The data is usually written on PVC tablets that are covered with a sheet of synthetic paper which one can write with an ordinary ball-point pen. Three-dimensional measurements of the sides are done with a gradiated frame. |
 |
| Artifacts numbered on the floor and photographed. Notice their "In Situ" position. |
 |
| Example of a plot, grid is set up prior to exploration of the site. |
| Analysis/Preservation |
| Various information can be obtained from underwater sites. Dendrochronological analysis can help determine the age of the wreck or items that were made of wood. More information on Dendrochronology can be found on the methodology/practice page. Carbonized material can be analyzed by particle accelerators or Carbon 14 dating. Radiography can be used to help find the internal structure of an artifact, detection of various other materials, location of the original surface, and deterioration. Electrolysis can be used to help clean underwater artifacts, such as lead, bronze or silver. It produces a reaction in the electrodes. It also stabilizes and decontaminates artifacts because of the effect it has on chlorites...which occur in ancient metals. This technique has also been used for some time for cleaning old coins. Simply drying artifacts by evaporation is potentially disastrous, especially with leathers and woods saturated with water. To prevent excessive damage, chemical treatment and lyophilization is applied. Lyophilization is when an item is frozen and then the solid moisture or ice is put under low pressure and directly converted to a vaporous state...this bypasses its liquid form. The vapors are then condensed on a rod that is kept at a low temperature. After this, artifacts are often protected by a low-temperature agent which is introduced in a "bath" such as glycol polyethylenes. |