Geothermal data on bolgarii. Geological structures

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Geological structures

The Basic sources of the information on a thermal stream are the researches spent in prospecting chinks. Regular data about the thermal stream defined as product of a temperature gradient on factor of heat conductivity, do not exist. Direct measurements of a thermal stream were not spent to Bulgaria.

The Thermal field is studied on the basis of data about temperature and a gradient on a surface and on depth. Character of the anomalies put on cards of isotherms, is compared to an arrangement of the basic geotectonic units taken on Jovchevu, etc.: the Rodopsky central file; the Mizijsky plate; the Alpine folded system and the imposed depressions. The Alpine folded system consists of the separate tectonic units which have arisen in the following age sequence:

1. Tectonic zone Sakar - Strandzha,

2. Tectonic zone Krajshte,

3. The West Balkan tectonic zone,

4. A tectonic zone Balkan forlanda,

5. A tectonic zone Sredna-mountain,

6. The Kulsky folded zone (Southern Carpathians),

7. The East Balkan tectonic zone.

In northern Bulgaria two areas strongly differing on structure and history can be allocated: one large and rather stable (the Mizijsky plate), another - young Alpine in which according to gipsometriej the base three parts are allocated: east (highly lifted), western (deeply shipped) and intermediate (transitive).

In east part two large structural raisings are allocated: northern Bulgaria and Dobrudja. This area is characterised by a positive gravitational field.

In the western part there is a Lomsky deflection, in an alignment with which extensive negative anomaly settles down. In a sedimentary layer three structures are allocated: kaledonsko-gertsinskaja, kimmerijskaja and Alpine. Are most in details studied Triassic and jursky - paleogenovyj structural floors. Comparison of their structural plans shows considerable discrepancy. But this reason regionalno-tectonic division of a platform on structural floors has been executed. In a direction on the east northern part of the Bulgarian range and a file of Dobrudja (a southern slope), and near to coastal area - Varnensky paleogen-neogenovyj a deflection settle down. Between east and western parts of a Triassic structural floor Plevensky and Levsky raisings are allocated, and the last is characterised by local temperature anomalies on depths in 1000, 1500 and 2000 m, shown on temperature cards.