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Morskie osady plejstoceńskie w Hergli (Sahel - Tunezja): znaczenie dwóch okresów wysokiego poziomu wód morskich w czasie ostatniego interglacjału

100%

Jedoui Y.

Prace i Studia Geograficzne

2006

tom 37

The aim of the research was to assess importance of two high sea level phases during the last interglacial period in Tunisia. The research was based on analysis of structure and petrography of marine sediments in a vicinity of Hergla by the Hammamet bay. The article describes consecutive sediment facies deposited during the upper Pleistocene, which allowed to reconstruct former sea limit. Two overlapping recessional sequences of a different origin (from subtidal to aeolian) were discovered. Sediments constituting these sequences consist of usually well rounded quartz grains and calcareous cement. These two sequences, separated by an erosional surface, were developed during two different phases of high sea level (much higher than today). The sediments were cemented in a fresh-water environment after their deposition, during progradation of the sea-shore. The researched sediments in the vicinity of Hergla are similar to coastal sediments found in the vicinity of Mahdia and also in other places along the southern part of Tunisian coast. This justifies the obtained conclusion. Lack of petrographical differentiation between the two sediment sequences in the vicinity of Hergla (which is not the case in southern Tunisia) is explained by an intensive supply of terrigenous material to the sea coast by the El Medjini Wadi during the upper Pleistocene.

Przykład powstawania dwóch przybrzeżnych mierzei piaszczystych w delcie poddawanej oddziaływaniu fal przyboju (południowe obrzeża Sfaksu)

45%

Gargouri D., Jedoui Y., Serbaji M. M., Rabia M. C., Montacer M.

Prace i Studia Geograficzne

2006

tom 37

The article describes development of two sandy bay bars located south of Sfax. The aim of the research was to determine the rate of growth of the bay bars and to find factors responsible for the process. The research was based on analysis of aerial photographs and textural features of sediments. The results show that the length of the bars grows c. 40 m/yr on average. This is linked to supply of detritus by the Wadi Chaffer which has its delta between the analysed bay bars. Developments of the bars is symmetrical on both sides of the delta and depends also on long-shore currents flowing in opposite directions along the delta coast. The bay bars are kinds of beach ridges 2 to 3 km long and consists of fine and medium, well sorted sand. Such a sediment is under permanent action of wind and swash waves. Lagoons protected by the bay bars constitute a low-energy environment and their floors are built with fine, poorly sorted sand. It is emphasised that the morphology of the bay bars is not stable and susceptible for high anthropopression in the region.

Ograniczanie wyników

2 Prace i Studia Geograficzne

2 Jedoui Y.

1 Gargouri D.

1 Montacer M.

1 Rabia M. C.

1 Serbaji M. M.

2 2006

Wyniki wyszukiwania

Morskie osady plejstoceńskie w Hergli (Sahel - Tunezja): znaczenie dwóch okresów wysokiego poziomu wód morskich w czasie ostatniego interglacjału

Przykład powstawania dwóch przybrzeżnych mierzei piaszczystych w delcie poddawanej oddziaływaniu fal przyboju (południowe obrzeża Sfaksu)