Nature park Persina: General information
The proposed park is situated along the Svishtov – Belene lowlands, including a part of the surrounding steep Danube coast around Nikopol and Svishtov and all the Bulgarian islands in that part of Danube river.
The Svishtov-Belene lowlands are a part of the Danube hilly plain. The length of this pan is about 38 km and the maximum width is 8 km. The whole surface is about 171 km’. It is an alluvial valley of quaternary origin, filled with clayey gravel silts of thickness up to 28 m. In the middle parts (between Belene and Dekov) it is higher (35 mi and is covered by silty-graveles formations. This high part divides the valley into two pans. w here the marsh of the Belene and Svishtov were placed in the past.
The poured terraces occupy 143,6 km2, and the unpoured ones – 27,4 km2 The first ones are situated 3 to 5 m above the river level at middle Danube waters. Barens and apts, silts and limestones serve as a plinth of the terrace. The accumulative cover, represented by alluvial sediments, reaches 28 m in depth. The first terrace, situated above the poured ones occupy the middle pan of the lowlands and it is at height level up to 10-14 m above the middle level of the river. Its profile is well-divided into accumulative cover and plinth. The accumulation cover consists of loess, loess-like formations and graveless-silty sediments that are covered by silty materials forming the characteristic longish eminenences – hills. Also a second terrace, situated above the first one could be found, occupying the level up to 17-25 m. Its surface is waved by the hills and loess plates.
The elevated coast occupies the easternmost and the westernmost pans of the park proposed. From the mouth of the Ossam River and Nikopol at the base of the steep coast gray and gray-white mergels of the second horizon of the maastrisht occur. Above them limestones of the maastrihts containing flints concretions could be observed. The Maastriht series continues eastwards from Nikopol, occupying the lower pan of the beach. The coastal slope near Svishtov uncovers rocky clans, which belong to the silty fades of the apt. In the region of Nikopol on the steep coast also some landslides could be observed, that determine its characteristic steppine-like relief.