ناحيه‌بندي سواحل جنوبي درياي خزر براساس شواهد مورفوديناميك رسوبي

Caspian Sea southern coasts zoning on the basis of sedimentary morphodynamic indicators

ناحيه‌بندي سواحل جنوبي درياي خزر به‌‌لحاظ صفات مورفوديناميك رسوبي بخش كم‌‌ژرفاي دريايي و خشك ساحلي هدف اصلي اين تحقيق است. پس از جمع‌‌آوري اطلاعات و پردازش اوليه آنها، با آشنايي لازم با منطقه مورد بررسي، محورهاي اندازه‌‌گيري ساحلي انتخاب شد. با اجراي عمليات ميداني مشخصات ساختار هندسي، عوارض مورفوديناميكي و ساختارهاي رسوبي بستر دريا مورد پايش قرار گرفت. درمجموع با بررسي تعداد 48 نمونه رسوبي برداشت شده از محدوده ساحلي در شش ايستگاه اندازه‌‌گيري (ميانكاله، سرخرود، نشتارود، انزلي، تالش و آستارا) و با اجراي عمليات آزمايشگاهي و پردازش‌‌هاي لازم روي داده‌‌هاي به‌دست آمده در محيط سامانه اطلاعات جغرافيايي مشخص شد كه سواحل جنوبي درياي خزر به لحاظ مورفوديناميك رسوبي به سه گروه سواحل فرسايشي، حد واسط و رسوب‌گذاري فعال ناحيه‌بندي مي‌شود.

In this research work the classification of the southern coasts of the Caspian Sea is performed using sedimentary and morphodynamic indices. This includes field study of morphodynamic characteristics of the shore structures. Field measurements include in situ samplings of sediments and actual observations of structures on site. These field activities were done along six transects in the dry coastal zones of Miankaleh, Sorkhrood, Nashtaroud, Anzali, Talesh and Astara regions. The sediments samples were taken from sea bed along 6 transects in these regions. About 48 sediment samples were taken directly as well as photographic observations of sea floor structures, using research diving facilities. The sediments were taken to the laboratory in order to find their materials and particle sizes. The sediment characteristics from all transects found by this method and observational data using direct photographic observations of morphodynamic structures were analyzed and presented on GIS maps. The GIS media can interactively acquire data from Excel files and help the analysis of the acquired results as tables and graphs. Results of the analyses show that different parts of these areas response differently to the hydrodynamic forces considering rapid sea level changes of the Caspian Sea in recent years. The results indicate that the beach area in these regions can be divided into 3 types regarding different flow regime conditions. Namely, low flow regime in the eastern part of the Caspian Sea Sothern coast (accretion beach), transition regime in the central part of Mazandaran and Gilan Provinces (intermediate beach) and high flow regime for the western part of Mazandaran coastal area (erosion beach).