CONSERVATION STUDIES AND WORK

Research and diagnosis

Many scientific investigations have been done with the purpose of finding out the structures’ and assets’ state of preservation and to make a diagnosis of each one of them: spheres, mounds or bases, and other work areas, be they domestic or funerary settings.

The five aligned spheres found in Finca 6 were totally excavated in the year 2013, with the purpose of knowing their preservation status.

During the works performed it could be observed 4 of them show cracks producing movement in parts of them. After their assessment they were covered again for due protection, and to take short-term measures. With the purpose of not letting water accumulate around the exposed sphere’s rim, natural drains were made use of, creating a slope which corrected the problem.

Analysis of the sphere at Grijalba-2 site revealed the presence of very deep cracks; one of them pierces through it, reason why the excavation was left half-buried.

Another important data is that the dimensions of each one of the spheres was obtained.

Work was done in the archaeological site Batambal for the reconstruction of a funerary rectangular structure, 8.70 meters-long by 2.30 meters-wide. The reconstruction had data taken during the archaeological research of the structure as reference.

Excavations were done around mounds 1 and 2 of Finca 6 site in 2015, to assess the preservation status of both. An interesting finding was made when conducting and verifying the measurements of the mounds’ diameters and discovering some sectors still have rows of stone, half-organized; in other cases the stones had been removed, product of looting activities of huaqueros in the past.

In the Grijalba-2 site, river stones were reintegrated on the central part of the access ramp to mound 2, where there was a large hole made by huaqueros with no stones, and in other parts the stones had been removed. To protect the unaltered sector the hole was filled with earth, and stones were placed in the hollow space.

A sector of mound 2 was also excavated, confirming the continuity of the pavement towards one side of the access ramp.

In December of 2015 a provisional roof was placed to cover the sphere on El Silencio site, with the purpose of protecting it from the harsh environmental conditions of the region and the accumulation of vegetation on its surface.

Studies and Work

• Testing with conservation materials

  

  Because patrimonial goods are irreplaceable, and that a faulty procedure can affect the physical integrity of the same, even their total loss, and based on the recommendations of an international adviser, some tests were done on materials with similar characteristics to those of pre-Columbian spheres.

  To analyze the behavior and reaction of rock materials and their possible implementation on the conservation of cultural property, different products made in Europe were used, unknown to our field.

  The samples taken were identified with the type of product tested. Some were left on the surface while others were buried, in the pre-Columbian sites of the southern region, as in the two facilities of the National Museum in San José (Bellavista & José Fabio Góngora). They were left there for one year.

  The exercise was important but not satisfactory, since it should have used samples in the same conservation conditions as cultural assets are; so it shall be carried out again under these considerations.

• Meteorological Station

  A meteorological station in Finca 6 site was installed by an agreement with the National Meteorological Institute, in October of 2014. The data contributed by the station will be very useful to document abrupt temperature and humidity changes of the area, needed for bio-deterioration studies.

• Hidrological Study

  At present search of specialists to implement a hydrogeological study is under way, which would also count with the support of SENARA (National Irrigation and Drainage Department).

• Topografic survey in 3D and photography

  A topographic survey in 3D of the 4 archaeological sites: Finca 6, Batambal, Grijalba-2 and El Silencio, was carried out at the end of 2015, owing to the contract with the company Geotecnologías S.A. The study generated very useful information for the precise location of the archaeological evidence, with national geographic coordinates, as well as photographic documentation of the conservation status of the archaeological sites.

• 3D survey of the sphere on the archaeological site El Silencio

  

  By an agreement with the University of Costa Rica, Lanamme UCR carried out as pilot plan, the 3D survey of the sphere located at El Silencio. Using a laser scanner the diameter of the same could be specified in 2.66 meters.

  This system could also serve to document the deterioration and superficial changes on the stone spheres, to keep a historical control of the deterioration, or on the contrary, the success of implemented conservation treatments.

• 3D survey of sites and spheres

  National Laboratory of Structural Materials and Models (LANAMME UCR)
  An interinstitutional collaboration agreement with Lanamme UCR was signed for the implementation of two pilot plans: one of them to survey the sites and spheres in 3D; the other one, to use a georadar in some areas of the archaeological sites.  This instrument passes through sediment deposited over the years on the original ground, allowing you to see what’s below, be it structures, objects, water reservoirs, etc.

• Biodeterioration studies

  
  Research Center in Molecular and Cell Biology - Universidad de Costa Rica  (UCR)

  

   

  A study of the effectiveness of biocides and hydro-repellents on archaeological materials began thanks to the contract with the Research Center in Molecular and Cell Biology the UCR.

  Collection and biofilms samples processing was done to that end, obtained from the spheres’ surface, both in the country’s southern region and on spheres found in the National Museum of Costa Rica’s facilities in San José.

  The different forms expressed by bio-deterioration were determined with this investigation, among them the coloring, and thin and thick biofilms, so divided for the study’s purposes. Information of the isolations according to the type of microorganism was generated, creating a collection of microbial resources associated to the spheres.

  The molecular and taxonomic identification of microbial isolates obtained from the spheres’ biofilms was also done, by obtaining the genetic material (Genomic DNA).

  For the next studies we count with having an effective biocide and hydro-repellent, to achieve a more efficient conservation of stone movable assets, above all those exposed to weathering.

• X ray Diffraction / Scanning electron microscopy

  School of Chemistry - University of Costa Rica (UCR)

  A mineralogical analysis with x-ray diffraction on dust of archaeological materials was performed by hiring the X-ray Diffraction Area from the School of Chemistry of the UCR. Sampling of the spheres on archaeological sites on the southern part of the country and in San José resulted in a mineralogical characterization, according to the diffraction patterns analyzed in the samples.

  The patterns’ data will be subsequently transformed into a numerical data matrix, to apply a series of statistical analysis. The data should enable the analysis of the main components and conglomerates, to determine the possible relations between the spheres.