Volume 12, Number 1, Jan. 1990, pp.5-8
Note: This paper was delivered at the 1989 WAAC Annual Meeting in Honolulu, Hawaii.
The topic of this presentation is the history of the archaeological site and of the regional culture of Oaxaca, emphasizing the conservation and restoration work done between 1987-1988.
This work has great significance since it is in the tomb that we find a harmonious meeting of Zapotec architecture, painting and sculpture. We also encounter the various problems that the specialist faces when trying to conserve painted murals, stuccos, and stone.
The concept of interdisciplinary work varies all the time, as does the conservator, the biologist, the photographer, the chemist and especially the archaeologist; as a result of the conservators' work it will be possible for us to admire one of the most important works of prehispanic Mexico.
In this conference I will speak about the conservation works done in the tomb, emphasizing the importance of in situ conservation and interdisciplinary cooperation in the conservation of cultural heritage.
Tomb No. 5 of Huijazoo is situated in the State of Oaxaca, in the southern part of the Mexican Republic, with an area of 95,364 square km (4.85% of the total of the country). It is adjacent to the states of Puebla and Veracruz to the north, the state of Chiapas to the east, the Pacific Ocean to the south and the state of Guerrero to the west. It is a very mountainous state and, therefore, it is difficult to reach.
In the prehispanic era, Oaxaca was the center of Zapotec and Mixtec culture. The Valley of Oaxaca, where the capital of the state is now located, was once the site of many of the most important cities of these cultures. Surrounded by mountains, it is approximately 95 kilometers long and 25 kilometers wide, and 1,500 meters above sea level. Three important valleys are found in this region: Etla, Tlacolula and Zaachila. The Valley of Oaxaca has the greatest agricultural potential and productivity, which explains why the Zapotecs reached their highest cultural development there.
During the classical period, Oaxaca distinguished itself as one of the principal cultural centers of Mesoamerica. Monte Alban, "City of the Dead", is the most important and most studied ceremonial site in the Valley of Oaxaca and is the cradle of the Zapotec culture. Monte Alban is situated on the top of a hill which suggests that defense was a factor in choosing the location.
Regarding Zapotec art, I will refer first to architecture which is characterized by stone constructions. The temples were constructed on a pyramid base. It is an architecture where space plays an important role. We find plazas, platforms and buildings joined in a great architectural balance.
Due to the fact that the region has considerable seismic activity, horizontal constructions were usually made, an example of which would be flights of stairs. Light also plays an important role in the architecture of Monte Alban, as seen in its beams and panels where the sunlight, when casting shadows, displays the massive character of the constructions. The columns and flat roofs are characteristic of this architecture.
Sculpture appears frequently as a complementary element to the architecture, as in lintels, steles or tablets, such as the Dancers of Monte Alban. The tablets made by the Zapotecs have a distinct religious feel; the cult of the dead was very important and we see it reflected throughout their culture.
The tombs play an important role. They are found scattered below the temples, palaces, platforms and patios, of which Huijazoo itself is a classic example. These developed from simple box shapes to those seen in Monte Alban shaped like a cross with sculpted entrances, carved niches and antechambers. The funerary chamber is generally covered by a flat or triangular canopy, the access door usually has a carved frame and reliefs, the walls are stuccoed and decorated with symbolic painted murals. The colors and techniques used give us an opportunity to learn about the history and evolution of the Zapotec culture.
Ecology plays a very important role in all cultures. In Oaxaca water is a valuable commodity since it rains only two months out of the year and therefore most of the population centers around the river. The ceremonial centers, on the other hand, are placed on hilltops for many reasons, such as defense from enemy attacks. The temperature fluctuates between 5 and 26 degrees Celsius.
The Tomb of Huijazoo dates from the Classical Period of the Zapotec culture (650-900 BC). It is located 29 kilometers to the north of the city of Oaxaca, now the capital of the State, in Etla Valley which is part of the municipality of Suchilquitongo. To arrive at the site one must cross the town of Suchilquitongo, and travel down two kilometers of narrow road, then continue on foot for the next 60 meters. At the site there is an esplanade made up of three mounds. The middle one is the principal pyramid, with a stone cross on the top where the people of the nearby town venerate their patron saint every year. On the right side of this mound is another which is as yet unexplored. On the left there is another small mound and under this one we find the tomb. The entrance is strategically placed: all approaching roads can be clearly seen.
The tomb is located under the mound at a depth of five meters. Access is by way of stucco-covered steps. The entrance was blocked by a large stone which has been removed.
Above the lintel there is a large stucco-covered mask worked in high relief, which is said to be the face of a snake with open jaws, from which the face of a red bird with large eyes emerges.
Following this there are two antechambers: the first is made up of two narrow niches where there are some designs of a red-orange coloring, but most designs have been lost; the second antechamber consists of two niches with three polychromatic walls representing various human figures.
On the north wall of the west niche, one can see a complete figure, totally dressed, which appears to be a priestess. She is wearing green and ocher earflaps, an elaborate headdress with rich plumage, and a dark red and white huipil. In her right hand she holds a green, orange and brown copal bag, the complete design outlined in black. In this room there are four lintels covered in stucco, in the center of each is a square painted red. Above the north lintel there is a large mask worked in high relief which is said to be the face of a jaguar with open jaws, wearing an elaborate headdress with geometric designs. From the jaws of the jaguar emerges the face and arms of a figure resembling a bat. These lintels rest upon stone blocks called jambs. There are ten jambs, each carved in bas relief, of distinctive figures with detailed vestments, painted red.
The floor of the tomb, as well as the steps to the funerary chamber, are made of stucco-covered earth. The funerary chamber consists of three walls, the east and west divided horizontally by a white line. The base of the walls is red- orange and the upper part shows a procession of human figures. All the figures wear headdresses of green feathers, as well as light brown dresses, pectoral plates and sandals. The faces of each have different expressions. Some of the figures have lost part of their detail and coloring. The lower level of the walls shows human figures of a different type, larger than those of the upper level, and their faces are those of animals such as jaguar and snakes. Their vestments are similar, consisting of a short skirt, bead necklaces, earflaps, and in one hand they carry a copal bag, while in the other they hold a stylized flower. All of the figures are facing north.
The north wall is the smallest, and has the fewest images. One can make out some green feathers and the remains of painted faces. In the central and highest part of the wall there is a small niche.
A stele decorated in bas relief was found in this room. It is divided in two parts: on the upper part there are two human figures, a young man with a skirt and bare torso, and in front of him an older man wearing an elaborate headdress, sitting in a position of higher rank. In front of this second figure there is a glyph of the long-nosed god wearing earflaps and a necklace, as well as a number glyph representing thirteen monkeys. On the lower part of the stele are the figures of a woman and an old man.
In the interior of the tomb various clay urns and vessels were found, as well as the skeletal remains of a young man. The peaked roof is made of large stone blocks, and the spaces between these are filled in with small stones and earth. The type of stone used to make the tomb can be found near the site and continues to be used by local people for construction.
Having finished with the formal description, we will address the most important issue of this conference: in situ conservation. First we must mention the conditions in which the tomb was found and the preventive measures taken before formal archaeological intervention was allowed.
The tomb was discovered in November of 1985 by the archaeologist Enrique Mendez, from the National Institute of Anthropology and History (INAH).
The project was handed over to the conservators of the Institute one month later. The tomb was in an advanced state of deterioration. The mural paintings were chipping away in 80% of the total wall area and were in danger of crumbling completely, especially in the spaces between the stone blocks. We determined that the damage was caused by seismic movements which caused the blocks of stone and the walls themselves to move, altering the paintings and stucco. This was exacerbated by the changes in temperature which occurred when the tomb was exposed upon discovery. In the rainy season, the entrance and antechambers of the tomb had been flooded, causing crystallization of salts on the painted surface of the jambs and alteration of color and design. We also observed that the red pigment was in an especially delicate state, crumbling at the slightest touch. Upon opening the tomb, a microclimate was formed which contributed to the proliferation of microorganisms. These were analyzed by a specialist.
For these reasons, we must take preventive measures and also provide careful maintenance. Due to a lack of funds, formal intervention did not take place until a year and a half after the discovery of the tomb.
One of the first measures taken to preserve the tomb was to protect the entrance and the mound against the rain with a canvas. We also documented the site using photography and compiled a formal register of the condition of the tomb. At the same time, pieces of Japanese paper were attached with the adhesive Mowital B 60H to areas where the painting and stucco were in danger of detaching. Also, the entire tomb was fumigated to prevent the proliferation of microorganisms.
After these preventive steps were taken, an interdisciplinary project for the conservation and restoration work was formed and work started in July of 1987. The project took nine months of constant work. Conservators, photographers, a chemist, a biologist and an archaeologist had direct participation, thanks largely to the support and participation of the Director of the Regional Center of Oaxaca, the State Government of Oaxaca, the town of Suchilquitongo, the help of the Director of Restoration at INAH, and the technicians.
We began the work with a photographic documentation of the tomb and continued this throughout the intervention. At the same time, we made graphic records of the floor plan and all details of the tomb. A specialist carried out an analysis of the materials used in the tomb's construction and decoration. The stone used for construction was found to be of the silicate family and is native to the site. The softness of this stone makes it possible to fashion it into jambs and such.
The pigments were found to be minerals. A biologist made an analysis of microorganisms and found filamentous algae and fungal organisms. The fungal organisms were of the Plyschema Indica type that can cause mechanical and chemical damage. The chemical damage caused black stains, the mechanical caused the crumbling of the stucco. The algae also caused stains.
Several biocide products were tested, by superficial application with a brush, in order to determine which one would be the best. It was determined that a 5% solution of sodium tetraborate in alcohol and water gave the optimum results.
In order to determine the climate of the interior of the tomb, we placed two thermograph units inside to measure relative humidity and temperature. Measurements were taken every eight days. Average temperature and atmospheric humidity readings were taken each week. The tomb's temperature varied between 20 and 25 degrees Celsius during this time, and the relative humidity varied between 45% and 80%. The humidity of the materials was determined to be 3%.
The reaction of the synthetic materials used in Conservation treatment and field restoration varied according to the climatic conditions in which they were used. Therefore, after the behavioral results of the consolidation materials were determined, we decided to use Primal AC 33, a synthetic resin, belonging to the acrylic copolymer family. This is a stable substance in high temperature conditions and is adhesive, colorless, and penetrates easily. We used this substance in concentrations of 10% and 20% in water and, in some cases, with slaked lime water, as we observed that this mixture helped to fortify the materials. This was applied superficially, with a brush or eyedropper, to the flat stucco surfaces and painting fragments found on the tomb floor in order to fix the surface colors in danger of detachment. Before the consolidation, ethyl alcohol was applied to the flat stucco surfaces for a better penetration of the consolidation materials.
The Primal AC 33 was also used, with very good results, for the consolidation of the surface color at 5% in water.
For reinforcing the plaster, hollow areas were located by tapping softly on the wall, and calcium caseinate was injected into the spaces between the plaster and the wall. This is an appropriate reinforcing material, since it consists of slaked lime. We decided to use this material because of its compatibility with the original materials. Casein is the principal protein of milk and it integrates well with the lime material that constitutes the wall and plaster of the tomb. It was applied by injection in areas previously treated with ethyl alcohol.
In order to secure stucco fragments in danger of becoming detached from the wall, various pastes and mixtures were used to repair cracks and fissures, and to reinforce the edges of the stucco work. The pastes and mixtures obtained from the traditional slaked lime, with sand and filler materials, gave us the best results. As a rule, a ratio of 3 to 1 is recommended for the lime mixtures; however, in order to ensure good results in this particular project, the filler materials had to be tested in each case. At the same time, the Japanese paper that was applied with Mowital B 60H as a preventive measure, was removed.
The colored fragments of stucco found on the floor were cleaned, consolidated, classified, and replaced in their original site. This was laborious work because many of them had lost their design elements and reference to the painting as a whole.
The steps leading to the interior of the Tomb which were covered with stucco, were cleaned and consolidated.
Although color integration in archaeological paintings is generally rejected in Mexico, in these paintings it was deemed appropriate because it promoted interpretation and understanding of the art work. Observing the international norms of intervention, only those areas where cracks interrupted the design were colored, and the intervention was made evident by the juxtaposition of colored lines, which is an Italian technique called reggattino. For these areas we used a fine base paste of lime with pigments and the juice of a species of opuntia cactus, native to Mexico, which is commonly eaten as a vegetable. This color base facilitated color integration.
Areas that were totally lost were dyed with a neutral color so that they remained in the background. For this we used a water and lime mixture with pigments. Prior to this we applied a layer of opuntia cactus juice which is an organic material that the prehispanics used as an agglutinate on paintings.
All the materials used in this intervention are reversible.
The last measure taken to protect the tomb was to install a grate at the tomb's entrance to prevent public access, and a roof over the entire mound to protect against the elements. The material used for the roof was galvanized metal sheets.
As one can see, in situ conservation is of great importance in prehispanic archaeology, as well as to all other cultural heritage.
In situ conservation is undoubtedly the archaeological triumph of our time since it allows us to better understand and appreciate the architectural and historical unity of cultural and archaeological sites.
We are struggling to leave behind the nineteenth century vision that created museums for works of art thereby removing them from their original locations. That practice is justifiable only as a last resort such as when security measures do not permit in situ conservation.Veronica Fernandez de Castro,
Espinosa, Agustin Ch. "La Restauracion: Aspectos Historicos y Tericos." Tesis Profesional. 1981. Mexico: INAH.
Gendrop, Paul (ed.). Arte Prehispanico en Mesoamerica. 1970. Trillas.
In situ Archaeological Conservation. Instituto Nacional de Antropologia e Historia and The Getty Conservation Institute. Proceedings of meetings. April 6-13, 1986, Mexico City.
Noguera, Eduardo. La Ceramica Arqueologica en Mesoamerica. 1975. Instituto de Investigaciones Antropologicas, UNAM.
de Tapia, Emily McClung. Ecologia y Cultura en Mesoamerica. 1979. Mexico: UNAM.
Whitecotton, Joseph W. Los Zapotecos: Principes, Sacerdotes y Campesinos. 1985. Mexico: FCE.