Gorgan Bay (GB) is a semi-enclosed basin located southeast of the Caspian Sea (CS), Iran. The Bay was registered as a biosphere reserve in 1976 and had an international focus on conservation. GB severely suffers from low water quality and water level. A hydrodynamic model was used to determine its general circulation, differences in temperature, water elevation, and current speed. This investigation includes the study of current vectors' profiles and analyzing the effects of rivers and air pressure in the circulation of this water body. The average current speed was determined to be 0.1 m/s through the Bay. The lowest and highest temperatures were investigated and were -0.53°C and +36.57°C, respectively. The general circulation is mostly counter-clockwise. Water elevation and temperature inside GB always follow a seasonal sinusoidal pattern. This paper neglects the effects of rivers on GB hydrodynamics due to their insignificance discharge. Also, the air pressure has a profound effect on the water level. Current vectors showed that while current speed inside this water body has decreased in the past decade, the temperature increased by almost 7°C.

Extreme coastal inundation associated with the 2004 Indian Ocean and 1945 Makran tsunamigenic– earthquakes highlight the risk of tsunamis to coastlines of the northern Oman Sea. Foraminifera have been used as indicators of paleotsunamis in the past where allochthonous tests, found in low– energy environments such as in coastal lagoons, ponds, and marshes, indicate marine overwash. In this study, we constrain the modern distributions of foraminifera from coastal Iran so that they may be used to identify and interpret (e. g. assess provenance) paleotsunami deposits in the geologic record. We collected surface sediment samples from sixteen sites within the study area from Chabahar to Gawater Bays on the Makran coast of Iran, selecting locations impacted by the 1945 Makran tsunami. Foraminifera obtained from these locations are dominated by supratidal, intertidal, and subtidal species, with minor abundances of planktic taxa. Samples collected from study locations are characterized by abundances of iron– stained and heavily corroded (e. g. edge rounded and pitted) individuals. Cluster analysis was used to determine three foraminiferal assemblages within the Makran coastal zone: subtidal, intertidal and supratidal. Characterizing modern distributions of foraminifera along the Makran coast of Iran will aid in identifying the provenance of older overwash deposits previously identified in this region.

Chabahar Bay is a semi-closed and shallow Bay in southeastern of Iran and is strongly affected by the monsoon conditions. The 3D FVCOM model was used to study the hydrodynamic conditions of Chabahar Bay. For this purpose, a horizontal grid with 6290 triangular elements and a vertical grid with 10 sigma layers were created. The model was implemented in baroclinic mode; NCEP data and HYCOM model outputs were used to account for open surface and boundary layer forces. Water level and flow velocity correlations show acceptable agreement with field data. The tidal Bay is often semi-daily and mixed and the tidal range is 2. 7 m. The flushing time of Chabahar Bay was calculated to be 6. 7 days. The modeling results show; The vertically and annual average current velocity is 0. 1 m/s and the rotation pattern is often anticyclonic.