Archaeology and geophysics in the Sboryanovo National Reserve

Geoarchaeology and Archaeomineralogy (Eds. R. I. Kostov, B. Gaydarska, M. Gurova). 2008.
Proceedings of the International Conference, 29-30 October 2008 Sofia, Publishing House “St. Ivan Rilski”, Sofia, 374-379.
ARCHAEOLOGY AND GEOPHYSICS IN THE SBORYANOVO NATIONAL RESERVE
(NORTH-EAST BULGARIA)
Diana Gergova, Ilijan Katevski
National Archaeological Institute with Museum, Bulgarian Academy of Sciences, 2 Saborna Str., 1000 Sofia; [email protected]
times building of the mausoleum of Demir Baba (Кovacheva,
1975). Later historical and archeoastronomic studies on Demir
Baba and his teke confirmed this date (Dermendjiev, 2004;
Gergova, Venedikova, 2007). The excavations in the courtyard
of Demir Baba teke provided by A. Balkanska (1998) and later
by D. Gergova (2006) proved also the existence of the
detected walls, which belonged to the Thracian sanctuary from
the I mill. BC, as well as to some later structures (Fig. 2).
The aim of the team of the National Archaeological Institute
with Museum (Bulgarian Academy of Sciences) which initiated
in 1982 the long-term investigations of the Sboryanovo reseve,
an area protecting the remains of the Getic religios and political
centre of the I mill. BC (“Dausdava” or the “City of the wolves”
on Tabula Nona of the Roman geographer Kl. Ptolemaios), as
well as later monuments from the Roman, Early and Late
Meideval times was to apply a vast range of interdisciplinary
and archaeometric studies, in order to obtain the most
exhaustive information about the structure, the chronological
frames and the history of the site (Gergova, 2008a).
The closest, permanent and most fruitfull partnership in the
field of the archaeometric studies was carried out between
archaeologists and geophysicists. The geophysical prospecting
became obligatory and preceeding the excavations
investigation of all sites of different type – settlements and
sanctuaries, tumular necropolises, tumuli, etc. It was precisely
in Sboryanovo that the views concerning the role and the
maximum effective application of geophysical methods for
investigating archaeological sites in general and especially
tumular necropolises were materialized.
Geophysical prospecting of some tumuli and sanctuaries
have been provided even before the beginning of these
investigations. In 1972 a team from the former Higher Institute
of Mining and Geology (University of Mining and Geology) led
by V. Ivanova and S. Pishtalov was assigned to perform
geophysical prospecting in the yard of the sanctuary Demir
Baba and of the Great Sveshtari tumulus. These investigations
were connected with the hypothesis about the possible location
of the tomb of the Bulgarian khan Omourtag and were carried
out in agreement with the Regional History Museum in
Razgrad (Teodorov, Gergova, 2006, 93, 104, Pl. XI).
Fig. 1. The geophysical prospecting of Demir Baba teke
The prospecting in the yard and outside the walls of Demir
Baba teke detected the existence of most probably ancient
stone walls (Teodorov, Gergova, 2006, 93, 104, Pl. XI; Fig. 1).
The first date of the construction of the main building of the
Demir Baba teke was obtained also by archaeomagnetic
methods. Sixteen pottery samples from Demir Baba teke were
analyzed in 1975. They were dated to the middle of the XVI c.,
showing the time of the construction of the existing till modern
Fig. 2. Plan of Demir Baba teke with the discovered walls of the Thracian
sanctuary
374
The geophysical prospecting in Sboryanovo was extremely
useful for the identification also of other types of graves and
structures in the field. The detection of such structures,
different from the monumental stone tombs was more difficult
and demanded a more detailed prospecting. One of the best
examples of the application of the geoelectric prospecting was
the investigation in 2004 of an area on the territory of the
Eastern necropolis, where the existence in the past of a
tumulus (N18) with totally destroyed embankment was
reported (Figs. 4-6). The archaeological excavations after the
localization of a small anomaly, revealed at a depth of 2.50 m,
a new, unknown from the territory of Sboryanovo type of a dug
out in the soil tomb with precious gifts. (Figs. 7-8). It enriched
the knowledge about the diversity of tombs and graves types
on the territory of the Getic royal necropolis dated to the end of
IV – beginning of the III c. BC (Gergova et al., 2005)
Ginina mogila (The Sveshtari tumuls) in the Northern part of
the Eastern necropolis was investgated in 1972 instead of the
Great Sveshtari tumulus in the Southern end of the necropolis.
During this prospecting the famous tomb in the South-Eastern
part of the tumulus, excavated in 1982 (Chichikova, 1992) was
detected for the first time. The next geophysical prospectings
in 1974, when 13 other tumuli were investigated, confirmed the
existence of the anomaly in Ginina mogila. The last
geophysical prospecting of the tumulus was carried out in 1982
(Radkov et al., 1984).
The geophysical methods applied in 1974 had contradictional
results and no other tombs were localised. Later, when the
geomorphology and dimensions of the tumuli (up to 20 m hight
and to 100 m diameter on loess) were taken in consideration
and a more elaborated approach to the geophysical
prospecting of the tumuli in Sboryanovo was applied, several
tombs were localized under some of these tumul, including the
two in the neighborhood of the Sveshtari tomb (Fig. 3)
(Katevski, 1992; Katevski, Monna, 2005).
The geophysical prospecting of the areas between the tumuli
both on the territory of the Eastern and Western necropolis
gave also important information about the existence of ritual
structures, slightly distinguishable by the air photography and
during the traditional archaeological survey.
Fig. 3. Ginina mogila with the Sveshtari tomb and tumulu 12 and 13
Fig. 5. The tomb discovered during the excavations - plan
Fig. 4. The results of the geoelectrical propecting of tumulus 18
375
Fig. 8. The archaeological finds from the tomb in tumulus 18, beads:
above – darkblue (left), pale blue (centre) and yellow (right); below –
complex beads
Fig. 6. The tomb discovered during the excavations – profile (above) and
photo (below)
A ritual complex of a rectangular stone construction with
three chambers, oriented North-South and two pits were
unearthed under a small stone tumulus on the territory of the
Western necropolis also after geophysical prospecting by I.
Katevski. Animal bones and fragments of preliminary broken
Thracian vessels and amphorae, dating the tumulus to the end
of IV – beginning of the III c. BC were found. The existence of
Early Iron Age pottery in one of the Hellenistic pits, brought
from the “Kamen Rid” sanctuary in its vicinity, revealеd an
interesting act that was emphasizing the ideological connection
with the earlier sacred site (Gergova, Valcheva, 2005, 71-73).
The results allowed to fill in the map of the Getic necropolis
with more tumuli both of a ritual and funeral character. They
were important also for the study of the structure of the
necropolis, for the discussions on its astronomically
determined space organization, which needed the most
precise map of the area, as well as for the understanding of the
social structure of the Getic society (Gergova, 1992, 12; Valev,
1996; Gergova, Kadijska, 2003).
The geoarchaeological partnership in Sboryanovo aimed not
only the detection of the anomalous area as preliminary
information for the archaeologists, but also the most detailed
possible characterization of the anomalous disturbance. It
became possible to get preliminary information even about the
degree of preservation or distruction of the tomb before its
excavation. This geophysical contribution had to be used for
the elaboration of more sophisticated and precise methods of
excavation. Having in mind the exact position of the tombs,
the profiles were to cross the investigated tumulus not through
the points of the compass, but through its most characteristic
Fig. 7. The archaeological finds from the tomb in tumulus 18, pottery
376
features (Gergova, 1992; 1992a; 1992c; 1998; 2000; 2008).
Thus a more objective documentation could be done as a base
for the discussion of some crucial questions, concerning the
burial practices of the Thracians. Better conditions were
created for the reconstruction of the burial and ritual activities
on front of the tombs.
the Bulgarian khan Omourtag. That is why its investigation
needed special attention (Teodorov, Gergova, 2006) (Fig. 11).
Its geophysical prospecting by I. Katevski in the beginning of
the 90-s of the last century detected an anomaly in the SouthEast end of the tumulus. During the excavations a
monumental tomb, destroyed by an earthquake in the
beginning of the III c. BC was found. The suggestion about the
existence of other constructions was confirmed much later,
when the use of more advanced instruments became possible.
The application of a “Terrameter” by a team, lead by the late
V. Vachev (Geological Institute, Bulgarian Academy of
Sciences) for the first time suggested the existence of an
anomaly in the centre of the tumulus. Later, in 2004, the
geophysical prospecting carried out by R. Varbanov, also from
the Geological Institute of the Bulgarian Academy of Sciences,
proved the existence of an anomaly almost in the centre of the
tumulus (Fig. 12). Geophysical prospecting was done also by
Y. Shopov from the Sofia University, confirming the earlier
localisation of the central anomaly.
As a result, the excavations of the Getic necropolis in
Sboryanovo allowed for the first time, not only in Bulgarian
archaeology, to explain the phenomena of the “plundered” or
“empty” Thracian tomb and to propose a reconstruction of the
misterious burial practices of the Getae, mentioned by the
ancien authors as “rites of immortalisation” (Gergova, 1992b;
1996).
There was also a practical aspect, connected not only with
the efficiency of the excavations, but also with the problems of
the conservation. The new method allowed to work in a
partnership with architects, climatologists and restaurers
already in the process of the excavations, to get prelimnary
information and to take the best decisions concerning the
preservation approaches of the discovered monument.
Information about the humidity, the micrrorganisms, the
construction stability of the tombs could be gathered before the
end of the excavations (Gergova, 1992; Petkov, Neshkova,
1992) (Fig. 9). Thus the discovered tombs under a properly
chosen type of protection building could have been preserved
and exibited easier and for a long time.
Fig. 10. Tumulus 12 with the destroyed by the earthquake tomb and the
profile showing the three main stages of the piling
Fig. 11. The Great Sveshtari tumulus at the beginning of the excavations
in the SE periphery
Fig. 9. The first microbiological samples from the tomb in tumulus 13
before entering the tomb
The methods applied for the excavations had another
positive result also for the wider public. In Sboryanovo the
visitors can see not only the tombs, but also to understand how
the tumuli over them were constructed in three phases and to
see traces of the burial and ritual practices preserved in situ
(Fig. 10).
The results of the geophysical prospecting depend also on
the technological level of the used geophysical instruments.
This is the case with the highest tumulus in North-East
Bulgaria – The Great Sveshtari tumulus is in the Southern part
of the Eastern necropolis of Sboryanovo. It is the tumulus
which marks the sacral territory of the Getic lands, but is
connected also with the hypothesis about its piling or use by
Fig. 12. The geophysical prospecting of R. Varbanov
377
The dimensions of the Great Sveshtari tumulus – about 20 m
height and its specific shape demands the providing of the
possibly most efficient excavations in interest of its
preservation. It is also for the first time on the territory of
Sboryanovo that a structure in the centre of a tumulus was
localised.
References
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Dermendjiev, N. 2004. L’orientation de Demir Baba teke. –
Helis, 4, 238-241.
Gergova, D. 1992. 10 years of the Sboryanovo Investigations.
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investigations of Sboryanovo. – Helis, 2, 9-22.
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tombs and its proposed solution: a new method applied
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The archaeological drillings to cheque the existence of this
anomaly in the centre of the tumulus and of other smaller
anomalies in the northern part of the tumulus lead to some
positive preliminary results. The ditch, surrounding the tumulus
was detected and studied in the North-East periphery of the
tumulus. The excavations in the West part of the tumulus – a
long trench, directed to its centre, lead to the discovery of a
living in the time of the construction of the tumulus tree – may
be part of the cult complex, which is situated in the centre of
the tumulus. The excavations in 2008 proved the existence
and of the larger anomaly, detected in the centre of the
tumulus and its character. It belongs to the earlier and smaller
tumulus, piled over the main structure, also detected by the
geophysical prospecting, which we expect to discover in the
centre of the tumulus. The lack of adequate funds for the
excavation of this unique and enigmatic monument both for
the Thracian as well as for the Bulgarian history is postponing
the finalisation of the project (Fig. 13).
Fig. 13. The Great Sveshtari tumulus
The geophysical prospecting of the Hellenistic town in
Sboryanovo aimed to define the occurrence of the root rock at
definite areas of the site by using the Vertical Electrical
Sounding method for the needs of the archaeological
excavations and also for the further elaboration of the
geoelectrical and geomagnetic prospecting of the site. The
results of the archaeological drilling based on the geophysical
results confirmed the existence of the localized anomalies
(Tonkov, Katevski, 2007).
The partnership between archaeologists and geophysicists in
Sboryanovo aimed to develop more precise and efficient
research methods at the first phase of the archaeological
investigations – the field work. It raised the level of all the
activities at the site – starting with the precision of the
excavations and their documentation, helping to develop
further on the application of the geophysical methods in
archaeology, as well as for the preservation of the monuments
in their specific natural miliex and their presentation to the
public.
378
Pametnitsi na Kulturata, 4 (in Bulgarian).
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determination the thickness of the cultural layers at the
locality “Vodna Centrala” in the Archaeological Reserve
Sboryanovo. – In: Prae. In Honorem Henrieta Todorova.
Sofia, 333-377.
Valev, P. 1996. A mathematical-astronomical study of the
Sveshtari burial complex. – In: Gergova, D. 1996. The Rite
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(in Bulgarian with an English summary).
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