Man's desire to know his past
The isolation to which the seabed has been subjected for centuries increases our expectations of discovering exceptional finds, even with greater incidence than in the terrestrial environment, in which all vestiges suffer greater degradation.
scuba diving allows you to discover countless impressive objects. But discovery in archeology does not mean rescue. Here discovering involves a process of study, before and after discovery, exploring and obtaining information about the site and objects and, in the end, exposing historical conclusions. That is, it requires a method.
Exploring has a high cost
Did you know that the first underwater archaeologists were terrestrial professionals at the end of the 19th century? They hired sponge and coral collector divers to describe the material remains they saw during their dives. Since then it has rained a lot, but at the bottom of the sea and in the field of underwater archeology, things have not changed that much.
Archaeologists, who previously paid for others to see under the sea with their eyes, now need sophisticated means of detection and location that allow them to discover and explore remote depths that are sometimes inaccessible to man. For this reason, archaeologists continue paying to be able to extract its secrets from the water. Whether with your personal presence in the exploration or in the use of modern detection equipment, the economic investment of any underwater archaeological project involves significant sums of money that often must be made profitable politically, economically or scientifically.
Documentation and prospecting
From everything we have seen, any project requires long and careful planning. Given the evidence of a possible site and after a documentation collection stage, field surveys are carried out.
Visual exploration methods, involving divers or remote-controlled video equipment, and other more sophisticated methods of locating remains can be used. If the place has enough reasons for study, it is finally time to excavate the site or postpone it for future campaigns.
What is an underwater exploration like inside?
The excavation begins a complicated process that, once underway, becomes irreversible for the extracted materials. If the information they contain is not correctly interpreted, it is irretrievably lost.
Each excavation is different. It depends, to a large extent, on the environmental conditions, the characteristics of the site and, logically, the material means available as well as the experts in diving. .
In general, most underwater excavations are organized on-site with various specialized teams. Some carry out underwater work and others serve as support for divers. Other members of the group act as auxiliaries on the surface and in maintenance and, finally, there are those responsible for receiving and storing the materials extracted from the bottom.
Sometimes the purpose of the project is not to excavate a shipment. The setting can be as different as the surroundings of the hull of a ship or the walls of a house covered in water. Be that as it may, the methodology used must guarantee that the final result allows for the documentary reconstruction of the position of the remains after removing the layers of sand or sediment that cover them.
The excavation process
When the place to be excavated has already been delimited, it is positioned topographically in the plane with respect to the ground. The process of extracting the different layers of sediment that covers the site then begins. The extraction technique, in each case, will depend on the person responsible for the excavation and the characteristics of the place.
The archaeologist uses different tools to remove these layers and leave the remains exposed. Perhaps the best-known instrument is the suction sleeve, which is inescapably related to underwater archaeology.
The suction sleeve.It is a means of support, once the sand or sediment that covers the reservoir has been removed by hand. The sleeve should never be applied directly on the bed of material since, with its suction, it would drag data and materials essential for the overall study. The sleeve sucks up the tank when it is already lifted from the bed and places it away from there, preventing it from settling again in the work area.
It works through a compressor located on the surface with which air is injected through a flexible tube through the rigid base of the sleeve. When the air rises to the surface, it causes a suction effect that is transmitted to the rigid end of the sleeve, sucking in what is located in front of the hole. Incorrect use of a suction sleeve can lead to a catastrophe in the reservoir, which is why they should never be left on the seabed without control.
At all times underwater archaeologists operate upside down, taking advantage of the weightlessness provided by the aquatic environment. In this way the deposit is not disturbed or damaged.
When the area of material is already free of sediment, it is documented using stereoscopic photography, video and/or drawing to record the situation as it appears. This is essential for a future reconstruction in a plane, already on the surface. Only when all this information has already been obtained, does the orderly extraction of the layer of archaeological material proceed, which, once on land, must be numbered, classified and cataloged for study. The excavation process is repeated and one layer after another is discovered until the excavation is completed.
The search instruments: one by one
Remains detection instruments are usually as sophisticated as they are expensive. The most used are:
- Side scan sonar. It is shaped like a torpedo and is dragged from a boat. It works by high-frequency acoustic waves that it emits horizontally on both sides of the path. Thanks to the rebound of these waves, a graphic image of the aquatic bed is produced in a way similar to aerial photography.
- The subsoil profile diagrammer. It uses the same technique but with low-frequency sound waves in vertical emission to penetrate the bottom sediments. The appearance of buried remains is reflected in a different response to the return of the waves.
- The proton magnetometer. Detects variations in the Earth's magnetic field caused by the presence of ferrous metal objects, whether they are buried or on the surface of the bed. The shape and magnitude of the anomaly will give us an indication of the mass of iron that produces it and the depth at which it is found.
Once the remains have been recovered
When all the material has been documented, a process of study and interpretation of the information provided begins, both in each piece itself and in its original location. It is a multidisciplinary phase in which chemists, who are responsible for the conservation of materials out of water, biologists and is located in front of the hole. Incorrect use of a suction sleeve can lead to a catastrophe in the reservoir, which is why they should never be left on the seabed without control.
At all times underwater archaeologists operate upside down, taking advantage of the weightlessness provided by the aquatic environment. In this way the deposit is not disturbed or damaged.
When the area of material is already free of sediment, it is documented using stereoscopic photography, video and/or drawing to record the situation as it appears. This is essential for a future reconstruction in a plane, already on the surface. Only when all this information has already been obtained, does the orderly extraction of the layer of archaeological material proceed, which, once on land, must be numbered, classified and cataloged for study. The excavation process is repeated and one layer after another is discovered until the excavation is completed.
The search instruments: one by one
Remains detection instruments are usually as sophisticated as they are expensive. The most used are:
- Side scan sonar. It is shaped like a torpedo and is dragged from a boat. It works by high-frequency acoustic waves that it emits horizontally on both sides of the path. Thanks to the rebound of these waves, a graphic image of the aquatic bed is produced in a way similar to aerial photography.
- The subsoil profile diagrammer. It uses the same technique but with low-frequency sound waves in vertical emission to penetrate the bottom sediments. The appearance of buried remains is reflected in a different response to the return of the waves.
- The proton magnetometer. Detects variations in the Earth's magnetic field caused by the presence of ferrous metal objects, whether they are buried or on the surface of the bed. The shape and magnitude of the anomaly will give us an indication of the mass of iron that produces it and the depth at which it is found.
Once the remains have been recovered
When all the material has been documented, a process of study and interpretation of the information provided begins, both in each piece itself and in its original location. It is a multidisciplinary phase in which chemists, who are responsible for the conservation of materials out of water, biologists and
