ultrasonic velocity of the western wall in the Stone Chamber before dismantling was shown to be in the highly weathered (HW) stage with an average ultrasonic wave velocity of 2,291 m/s and coefficient of weathering (K) of 0.55. Therefore, we identified that the degree of weathering on the Stone Chamber is worse than that of the Stone Standing Buddha, which is assumed to be due to the exposure of continuous creep and complex physical damage over long periods (Lee, 1998). Creep that occurs to the west of the lower ground of the western wall causes structural imbalance, resulting in partial load difference that adds to the crack. Consequently, if this phenomenon lasts, the weathering of the masonry becomes more severe and the physical properties become weaker.
To select the substitute stone for damaged parts of the Stone Chamber, the petrographic homogeneity with granite in the surrounding area was examined. Samples used in the analysis were collected in Mungyeong, Danyang, Sangju, and Mireukri in Chungju. Considering the petrographic characteristics, the magnetic susceptibility and geochemical characteristics, the granites around Mireukri in Chungju are the most similar, and the second–most-similar is the quarry in the Mungyeong area (Kim and Shin, 1990). Therefore, it is reasonable to utilize the rocks from these areas as alternative stone in terms of authenticity of the cultural heritage.
Also, the availability of rocks used for the stone cultural heritage around the Mireukdaewonji was investigated. The results of investigating the old cutting traces, petrographic characteristics and the distribution of magnetic susceptibility, showed that there is a similarity between the stone cultural heritage and nearby rocks. It is supposed that there is a possibility to obtain stone from neighboring rocks when constructing stone cultural heritage because a river transportation system has not been developed on a large scale. However, it is necessary to reveal more direct and clear grounds through further quantitative analysis with regards to this.
This study will provide the basic data for making a stable conservation management plan of the Stone Standing Buddha and Stone Chamber, and choosing a substitute stone for masonry repair. It will also be used as an important source of regular monitoring after repair works, helping to determine the progress of damage.
References
Jeong, S. K., 2008, A study on the opening period of ‘Jungwon Mirekri temple site’. Dongak Art History of Korea, 9, 145–172 (in Korean with English abstract).
Jo, Y. H., Lee, C. H., 2014, Quantitative modeling of blistering zones by active thermography for deterioration evaluation of stone monuments. Journal of Cultural Heritage, 15, 621–627.
Kim, H. R., 2008, A study on the Construction method of the Stone chamber for protection at mireukri temple site in Jungwon. Journal of Chungbuk Research Institute of Cultural Heritage, 1, 51–70 (in Korean with English abstract).
Kim, K. H., Shin, Y. S., 1990, Petrochemistry of the granitic rocks in the Chungju, Wolaksan and Jecheon granite batholiths. Economic and Environmental Geology, 23, 245–259 (in Korean with English abstract).
208Lee, C. H. and Jo, Y. H., 2017, Correlation and correction factor between direct and indirect methods for the ultrasonic measurement of stone samples. Environmental Earth Science, 76, 477–489.
Lee, S. H., 1998, Weathering and crack development in the rocks of protecting-chamber for Standing-Buddha of Mireuk-ri temple site at Jungwon. Journal of the Korea Society of Conservation Science for Cultural Properties, 7, 68–79 (in Korean with English abstract).
Ryoo, S. L., 2018, A study on the original shape of the stone structure of Maitreya temple in Chungju City. The Journal of Cultural Heritage, 22, 263–293 (in Korean with English abstract).
209
DECAY OF PRE-COLUMBIAN PHALLIC STONE MONOLITHS
Christopher Pötzl1, Ali D. Öcal2, Thomas Cramer3, Siegfried Siegesmund1
IN: SIEGESMUND, S. & MIDDENDORF, B. (EDS.): MONUMENT FUTURE: DECAY AND CONSERVATION OF STONE.
– PROCEEDINGS OF THE 14TH INTERNATIONAL CONGRESS ON THE DETERIORATION AND CONSERVATION OF STONE –
VOLUME I AND VOLUME II. MITTELDEUTSCHER VERLAG 2020.
1 Geoscience Centre of the Georg August University Göttingen, Germany
2 Department of Anthropology of the National University of Colombia, Bogota, Colombia
3 Department of Geosciences of the National University of Colombia, Bogota, Colombia
Abstract
The pre-Columbian astronomical and meteorological observatory of El Infiernito or ‘Little Hell’ is situated within the Monquirá Archaeological Park, near the colonial town of Villa de Leyva in the Colombian Boyacá-Department. Several burial mounds and a variety of phallic-shaped monoliths, made of local sandstone, bear witness to the culture and unique masonry of the ancient Muisca culture. The El Infiernito ranks among the most important historical and cultural monuments in Colombia. The monoliths were erected nearly two millennia ago and show severe damages today that developed over the time since its construction. Depending on their exposition, various weathering phenomena like differential back-weathering, scaling, cracking and discoloration can be observed. In order to identify the main damage causes and understand their relation with the stone properties, in-situ investigations, in the form of lithology and damage mapping, as well as laboratory work regarding petrography, petrophysical properties and weathering behavior of four sandstones were done. The research demonstrates the differential weathering behavior of the analyzed sandstones and identifies thermal and thermohygric expansion as the main weathering agents.
Keywords: Colombia, El Infiernito, monoliths, sandstone decay, damage assessment, weathering processes
El Infiernito: Historical Background
The stone monoliths at El Infiernito (Fig. 1) have been the subject of much attention ever since the earliest Spanish missionaries, because of their claimed associations with controversial Muisca rituals and alleged riotous ceremonies (Simon 1981). The arrangement of 26 finely carved and equidistant cylindrical pillars in two parallel rows led Silva Celis (1981) to the conclusion that the archaeological 210site had been a sacred field of astronomical and meteorological observation. The natives had measured the movements of the sun, and thus, solstices and equinoxes were calculated and periods of rain and drought were established, which regulated the production activities of the natives (Silva Celis 1981). A dolmen tomb found in 2006 together with 54 phallic-formed sandstone monoliths and indications of feasting events, suggest that El Infiernito was a central place where inter-community activities were carried out.
Figure 1: General view of the archaeological park.
In this study, preliminary results of an investigation
