Geological Problems of the Cave Monastery Complex of Vardzia (Georgia)

Combining InfraRed Thermography and UAV Digital Photogrammetry for the Protection and Conservation of Rupestrian Cultural Heritage Sites in Georgia: A Methodological Application

“…This formation can be divided into two sections: (i) upper lava flows (of andesitic, dacitic and rhyodacitic composition with rare occurrence of basaltic rocks), 600-700 m in thickness, (ii) lower pyroclastic deposits 200-250 m in thickness, formed by volcanic breccias and tuffs of different size (from 1 m maximum to millimeter) with andesitic-dacitic composition. The Goderdzi formation is also discordantly covered with thick series of Quaternary age dolerites and basalts of the Akhalkalaki suite [25][26][27][28]. The regional tectonics is characterized by a regional normal fault trending SW-NE along the Mtkvari river gorge, separating the Erusheti block to the west from the Javakheti block and the east [27,28].…”

“…The geology of the Vardzia cliff is characterized by volcanoclastic succession formed by four thick volcaniclastic layers ( Figure 5), from bottom to top: (i) "Lower Breccia"=Level 4: a 250 meter thick lower layer consisting of dark-colored lava breccia of andesitic and andeso-dacitic composition, with mainly sharp-grained material (with 3-6 cm clast dimension), predominantly weakly cemented, (ii) a 20 to 80-meter thick layer of light-colored weakly cemented small-grained tuffs, also called in literature "Vardzia horizon" or "Vardzia Ignimbrite", characterized by felsic, andesitic-dacitic and dacitic composition ( Figure 2c) [13,[23][24][25][26]. This layer is in terms subdivided into two layers: (ii) a lower level, namely "Grey Tuff"=Level 3, made of 1-3 cm material consisting of lapilli-tuff with dark pumices, scorias and bombs; (ii) an upper level, namely "White Tuff"=Level 2, formed by lapilli-tuff with white pumices, and a thin level of volcanic ash, 0.3-0.6 m in thickness (very soft and highly weathered); (iii) On top of the succession lies the bottom section of the upper Goderzi Formation, here comprised of a sharp-grained dark volcanic breccia layer, namely "Upper Breccia"=Level 1, of andesitic and andesitic-dacitic composition.…”

Rockfall at the heritage site of the Tatlarin Underground City (Cappadocia, Turkey)

“…These instabilities are frequently due to the different mechanical behavior of superimposed lithologies and their intrinsic weakness. Other examples of cultural heritage in tuffs and ignimbrites include some of the Buddha statues in Japan (e.g., Heiwa-Kannon statue, Oguchi and Yuasa 2010), the Moai statue in the Easter Islands (Gioncada et al 2010), the Macusani rock art site in Peru (Hostnig 2008), the underground cities of Vardzia in Georgia (Tutberidze and Tsutsunava 2015;Margottini et al 2015) and Kandovan in Iran (Kaljahi and Birami 2015), and the rock-hewn churches of Lalibela in Ethiopia (Delmonaco et al 2005;Renzulli et al 2011). In Turkey, apart a few exceptions (Binal and Ercanoglu 2010;Topal et al 2007Topal et al , 2012, the majority of engineering geological studies on instabilities at the heritage sites are concentrated in Cappadocia (Doyuran 1976;Aydan et al 2007;Ulusay et al 2006;Tunusluoglu and Zorlu 2009;Tuncay 2009;Zorlu et al 2011;Kaşmer et al 2013).…”