Dobrogea Geology

Introduction

In the past years extreme phenomena such as floods, drought, landslides and changes of relief were more and more frequent, with a general tendency of increase in the pluviometric regimen.

These phenomena are due to common action of various factors such as: the morphometric characteristics of the hydrographical basins represented by relief and the size of the receiving surface, the geology of the soil, the land’s degree of saturation with water, vegetation, degree of erosion of the soil, etc.

Although the geological conditions of the area do not decisively influence the climatic conditions, the geological structure of the Dobrogea region can influence the phenomena of flowing, infiltration and accumulation of waters in the subterranean structure of the land; this is why we are going to present the geology of the Dobrogea area.

“Maybe none of the Romanian provinces reflects, in its morphology, the interdependence between the modifying agents of the land and the geological structure, as Dobrogea does. In the current relief, continuously shaped during earlier geologic times, but especially during the Pliocene and Quaternary period, the geological structure is sketched with a remarkable clarity. Therefore, the morphological structures overlap the structural geological units presented above.”

The Dobrogea area (figure 1) is in the south-east part of Romania, comprising two important faults, Peceneaga- Camena (P – C) and Capidava-Ovidiu (C – O), which divide Dobrogea into three sectors: North Dobrogea (1), Central Dobrogea (2) and South Dobrogea (3) .

Figure 1.

Maps of Romania (simplified by G.B. Cazacu 2014)

1. North Dobrogea

The North Dobrogea area represents a major tectonic unit delimited in the north side by the Danube Delta, in the south by the Peceneaga-Camena Fault, in the east by the Black Sea, and in the west by the Danube River.

The North Dobrogea Platform is also known as the Land of the peneplanized mountains of Dobrogea because they correspond to an area where eroded old mountains and hills appear (the Caledonian chain and the Hercinic chain).

The geological map of Dobrogea is presented in figure 1 acording to the 1: 500 000 scale Geological map, simplified by G.B. Cazacu 2014.

The geological structure of this area is the most complicated from Dobrogea and, for this reason, in order to obtain the most accurate image possible, other geomorphic sub-areas were determined.

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  The Măcin Mountains area – in the western side, partially metamorphosed Palaeozoic formations and granitic massifs can be seen;

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  The east area (the area of the city of Tulcea) – Triassic deposits in facies, mainly limy, are developing;

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  The Babadag Basin area – in the south side, a limy facies is also developing.