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Top view of the buried building at Naryn-Kala fortress, Derbent.        Source: Credit: © NUST MISIS

Subterranean ‘Water Tank’ Is Actually the Oldest Christian Church in Russia, Say Nuclear Physicists

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The conclusion of a team of scientists testing the hypothesis of archaeologists about the use of a building in the Derbent fortress of Naryn-Kala as a Christian temple is that it is ‘most likely to be true’. If this theory is confirmed, this building is one of the oldest churches in the world.

NUST MISIS scientists together with the colleagues from P.N. Lebedev Physical Institute of the Russian Academy of Sciences of the Russian Academy of Sciences, Skobeltsyn Institute of Nuclear Physics Lomonosov Moscow State University and Dagestan State University published the first results of a "scan" obtained by the method of muon radiography of the underground space in the Derbent fortress of Naryn-Kala.

Subterranean Worship Speculations

The 12-meter building is almost completely hidden under the ground, only a fragment of a half-destroyed dome is visible above the surface. The building is located in the northwestern part of the Naryn-Kala fortress in Derbent and dates back to about 300 AD. To date, the issue of the function of the building has not been resolved, with various speculations claiming that it is a reservoir, a Christian temple, or a Zoroastrian fire temple.

If this is really a Christian temple, then we can talk about the oldest in the country - and one of the oldest Christian churches in the world.

The building was hidden for centuries after being covered with soil by Arabs after the capture of Derbent in about 700 AD.

The modern wire frame covers the building in the Naryn-Kala citadel. (© NUST MISIS/CC BY 4.0)

The modern wire frame covers the building in the Naryn-Kala citadel. (© NUST MISIS/CC BY 4.0)

An Innovative, Non-invasive Method

It has not been possible for archaeologists to come to a consensus on the buildings function because the excavations of the temple, used for two centuries as a reservoir, could have destroyed what is a UNESCO cultural heritage site.

Therefore, to study the premises, scientists initially used the method of muon radiography, placing several innovative detectors with a nuclear emulsion inside a buried building at a depth of 10 meters (33 ft) from the surface of the earth. The research lasted from May to September 2018, with the first data obtained confirming the effectiveness of the method for the study of this specific object.

The purpose of the experiment was to find out the possibility of studying the selected archaeological object using muon radiography, determine the optimal exposure, the number, size, and location of the detectors, get the first images of the object using nuclear emulsions.

The results obtained from the muon detector made it possible to confirm the reliability of the study of the building using muon radiography and suggest a plan for a full-scale experiment to identify the contours of the building as a whole.

In addition, in the first test experiment physicists "saw" an unusual distribution of muon fluxes in the western wing of the building, which may be related to the architectural features, indistinguishable by fragments of walls located above ground.

(a) The cross-section view of the construction, dimensions are given in mm. (b) Computer reconstruction of underground building. (© NUST MISIS/CC BY 4.0)

(a) The cross-section view of the construction, dimensions are given in mm. (b) Computer reconstruction of underground building. (© NUST MISIS/CC BY 4.0)

Revealing Dimensions

The construction, built of local shell-limestone, is about 11 meters (36 ft) high and extends 15 meters (49 ft) from south to north and 13.4 meters (44 ft) from west to east. Segments (or arms) of a cruciform design have a width of about 5 meters (16.4 ft), three arms of a length of about 4.2 meters (13.8 ft), and the fourth (northern) -- more than 6 meters (19.7 ft). The brackets are covered with vaults, and a dome wire frame with a diameter of 5 meters (16.4 ft) is located above the central part.

In a number of historical and reference sources, this construction is referred to as an underground water tank, as it was in the XVII -- XVIII centuries. However, the first experiment gave reason to doubt this hypothesis.

The main reasons for the interpretation of this building as originally being a religious building is its cross-shaped design and its orientation to the cardinal directions. This is very unusual for reservoirs, but common for early churches and fire temples.

Naryn-Kala fortress was taken by Arab invasion of Derbent in 700 AD. (© NUST MISIS/CC BY 4.0)

Naryn-Kala fortress was taken by Arab invasion of Derbent in 700 AD. (© NUST MISIS/CC BY 4.0)

According to the lead scientist of the group, Natalia Polukhina, Ph.D. in Physics and Mathematics, and NUST MISIS leading expert:

"It seems very strange to me to interpret this building as a water tank. In the same fortress of Naryn-Kala, there is an equal underground structure of 10 meters depth, and it really is a tank. This is just a rectangular building. The unusual building, in which we have put our detectors, has the shape of a cross, oriented strictly to the sides of the world, one side is 2 meters longer than the others. As the archaeologists who began excavations say, during construction, the building was entirely on the surface and it stands on the highest point of the Naryn-Kala. What is the sense to put the tank on the surface, and even on the highest mountain? It is strange. Currently, there are more questions than answers."

As the authors of the study emphasize, the characteristics of the probing radiation at this object require the subsequent irradiation of muon detectors in the area under study, and therefore, the continuation of the experiments.

The installation of detectors on the western slope of the fortress outside the walls of the building will be especially effective in order to obtain its full-size underground image.

The main result of the next stage of the experiments will be the final three-dimensional tomogram of the underground building, which will help to define the purpose of this unusual facility.

Top image: Top view of the buried building at Naryn-Kala fortress, Derbent.        Source: Credit: © NUST MISIS

This article is based largely on a press release from MISIS , National University of Science and Technology, Russia.

Source: Abiev, A.; Bagulya, A.; Chernyavskiy, M.; Dashkina, A.; Dimitrienko, A.; Gadjiev, A.; Gadjiev, M.; Galkin, V.; Gippius, A.; Goncharova, L.; Grachev, V.; Konovalova, N.; Managadze, A.; Okateva, N.; Polukhina, N.; Roganova, T.; Shchedrina, T.; Starkov, N.; Teymurov, A.; Tioukov, V.; Vasina, S.; Zarubin, P. Muon Radiography Method for Non-Invasive Probing an Archaeological Site in the Naryn-Kala Citadel. Appl. Sci. 2019, 9, 2040.

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