Yapay Zeka Hızlı Bakış & Çıkarımlar
AI InsightThe present-day sea-level has been seen at still-stand period for the last millenia.
📌 3 Maddede Bu Makale
Özet
In the southern coastal zone of the Sea of Marmara (northwestern Turkey), two important rivers. Kocasu and Gönen, debouch into the sea, with a distance of less than 80 km from each other. The discharge and transport of appreciable amounts of sediment load are due to the prevailing semi-arid climate with wet-winter seasons. The sedimentary input of Kocasu and Gönen rivers have produced two quite morphologically different delta systems. The Gönen river delta is lobate and fluvialdominated with sediment accumulation having a progradation of 5.5 km and subaerial plain of 28 km2 totally. The meandering distributary channels and a number of small lagoonal lakes are the main elements of the delta plain. The input of sediment is abundantly bedload and has resulted in the development of a triangular delta plain, with a slight shifting towards the east. A steplike scarp at 6 m altitude divides the plain into two parts. Two drillings of DSl at apex of the delta show that overall deltaic sequence is 65 m thick, however delta plain sediments are generally 6 m thick. The Kocasu delta is characterized as a highly mud-dominated delta, a specimen of a destructive, curvi-linear delta type. It is a wave-dominated river delta with a 3.5 km of progradation and a subaerial plain of 48 km2 . The present Kocasu delta has only one straight, major channel. The extensive lateral growth of the delta is provided by wave actions, mostly created by northeasterly winter winds. Fluvial sediments on the delta plain are limited extent. Consequently, actual fluvial sedimentation on the delta plain is low and, two lagoonal lakes, swamps, cheniers, dunes and a long sandy beach are the basic morphological elements of delta plain. A step-like morphology at 4 m altitude, similar to that of Gönen river delta, separates the delta plain to a relatively older and a younger formations. Total thickness of the deltaic sediment body is estimated to be 55-60 m by graphic correlations. Both deltas abound in active right lateral strikeslip faults and their depositional areas were limited by bedrocks on the seashore. Limitation is very typical and sharp in the Kocasu delta due to the presence of fault scarps on the Palaeozoic metamorphics. Geomorphology of drainage areas shows that the modern Kocasu and Gönen river deltas are synchronique deposits and they must have began to develop in early Holocene. The step-like morphology on delta plains may indicate a global sea-level fall to the present level, most probably since the last climatic optimum. Later, local sea-level changes in Kocasu area took place, creating long cheniers in swamp sediments by the activity of the faults on the sea shore. The present-day sea-level has been seen at still-stand period for the last millenia.
Abstract
In the southern coastal zone of the Sea of Marmara (northwestern Turkey), two important rivers. Kocasu and Gönen, debouch into the sea, with a distance of less than 80 km from each other. The discharge and transport of appreciable amounts of sediment load are due to the prevailing semi-arid climate with wet-winter seasons. The sedimentary input of Kocasu and Gönen rivers have produced two quite morphologically different delta systems. The Gönen river delta is lobate and fluvialdominated with sediment accumulation having a progradation of 5.5 km and subaerial plain of 28 km2 totally. The meandering distributary channels and a number of small lagoonal lakes are the main elements of the delta plain. The input of sediment is abundantly bedload and has resulted in the development of a triangular delta plain, with a slight shifting towards the east. A steplike scarp at 6 m altitude divides the plain into two parts. Two drillings of DSl at apex of the delta show that overall deltaic sequence is 65 m thick, however delta plain sediments are generally 6 m thick. The Kocasu delta is characterized as a highly mud-dominated delta, a specimen of a destructive, curvi-linear delta type. It is a wave-dominated river delta with a 3.5 km of progradation and a subaerial plain of 48 km2 . The present Kocasu delta has only one straight, major channel. The extensive lateral growth of the delta is provided by wave actions, mostly created by northeasterly winter winds. Fluvial sediments on the delta plain are limited extent. Consequently, actual fluvial sedimentation on the delta plain is low and, two lagoonal lakes, swamps, cheniers, dunes and a long sandy beach are the basic morphological elements of delta plain. A step-like morphology at 4 m altitude, similar to that of Gönen river delta, separates the delta plain to a relatively older and a younger formations. Total thickness of the deltaic sediment body is estimated to be 55-60 m by graphic correlations. Both deltas abound in active right lateral strikeslip faults and their depositional areas were limited by bedrocks on the seashore. Limitation is very typical and sharp in the Kocasu delta due to the presence of fault scarps on the Palaeozoic metamorphics. Geomorphology of drainage areas shows that the modern Kocasu and Gönen river deltas are synchronique deposits and they must have began to develop in early Holocene. The step-like morphology on delta plains may indicate a global sea-level fall to the present level, most probably since the last climatic optimum. Later, local sea-level changes in Kocasu area took place, creating long cheniers in swamp sediments by the activity of the faults on the sea shore. The present-day sea-level has been seen at still-stand period for the last millenia.