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Margarita_matova_3

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									    TRANSFORMATION OF ISLAND IN PENINSULA IN THE REGION OF THE
                 TOWN OF POMORIE (E BULGARIA)

M. MATOVA
Geological Institute, Bulgarian Academy of Sciences, Sofia 1113, Bulgaria
e-mail: matova@geology.bas.bg

    The town of Pomorie is situated in the central         also by the periodicaly occured strong sea erosion.
part of the wide Bourgas bay. It is 21 km to NE            The constant erosion is of limited influence. Its
of the town Bourgas. Now the town is developed             effects are located generally to the E and to the S of
over the small Pomorie peninsula (3 km in length,          the Pomorie lake. The strong erosion, going up to
1 km in width, 5-7m in height). It is correctly to         the partial barrier’s destruction, is due to the every
mark that the old town of Pomorie was placed only          4-5 years repeated sea storms. The barrier’s
over a small island. The town has very rich                destruction is realized mainly in the northern part of
political, economic and cultural history. Later,           the lake’s coast. The town Pomorie is transformed
the island was connected with the coast by two sand        into island during the cited periods. Several of the
barriers (tombolo). The Pomorie lake-laguna (6 km          secondary transformation of the peninsula in an
in length, 0.8-1.8 km in width, 1.5 m in depth and         island are marked in the historic documents. The
with 60-80% salinity) is placed between the two            summary effect of the sand barrier’s destruction is
barriers (30-200 m in width). So the island was            of value of 12 mm/a (Marinski, 1998). The negative
transform in a peninsula as a result of the                vertical epirogenic movements of value up to 2
development of the barriers. The recent town and           mm/a are established in the Bourgas bay. The sea
the railway were built over the island, the sand           level             is             rising           with
barriers and the coast. The Pomorie lake is used for       an average values of 3.0 mm/a (Marinski., 1998) in
the salt production and the mud-curing. The town           the second half of the the 20th century, despite
has a famous balneological center. Its wines and sea       the above mentioned epirogenic subsidence. Some
salt production is reputed in their high quality.          of the antique parts of the town are covered by
    The Sarmatian calcareous sands are represented         the sea water now. The tectonic, including
in the Pomorie island. Two Quaternary sand                 the seismic activity of the territory is not
barriers are located mainly to the N and                   considerable. The local seismic events could be of a
the NW of the island. The cited barriers had realize       maximal magnitude value M<5.0 (Bune et al.,
the connection between the island and the coast. So        1982).
the Pomorie peninsula was formed. It could be                  The recent geoenvironment conditions could be
interpreted as a result of constructive tendencies         characterized by a general constructive tendency
of the development. The peninsula is a Quaternary          and by several secondary destructive ones.
structure. It is subjected mainly to the sediment          The intensive sedimentation and the evolution
accumulation. Now there are a permanent                    of the sand barriers (tombolo) are very important
sedimentation over the sand barriers and the coast.        for
The quantity of the sand is very considerable.             the development of the town in the past, now and in
The Quaternary formed peninsula structure is not           the future. The destruction of the sand barriers is
well stabilized.                                           of a relatively limited significance and of a temporal
    The peninsula is subjected also to the destrucive      manifestations. The cited effects needs special
processes. The destructive processes are                   attention and technogenic activity.
represented by the sea erosion, the changes of the             The long-term stability of the town and
sea level, the epirogenic and the tectonic                 the peninsula in the future is problematic, if the rise
movements.                                                 of the sea level will be prolonged. The protection
    The cited barriers are transformed and partially       of the town of Pomorie and the Pomorie peninsula
destroyed by the constant and small sea erosion,           is of national and international significance.

                                                 REFERENCES

Bune, B.I., Vuchev, V.T., Gitis, V.G. & Mironov,           Marinski, J. (Edit.-in-Chief). 1998. Protection and
   M.A. 1982. Application of the interval expert             long-term stabilization of the slopes of the Black
   evaluation approximation method to compilation            Sea coasts. Acad. Publ. House “Prof. M.
   of M max maps of Bulgarian earthquakes. -                 Drinov”, Sofia , 199 p.
   Geologica Balcanica, 12,2, p. 49-70.




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