Impact of hydrological changes and vertical motions on Pleistocene marine environments of the eastern coast of the island of Rhodes (Greece)

Abstract

The island of Rhodes in the eastern Mediterranean Sea is situated in an area affected by an ongoing plate convergence, and its Pleistocene marine environments were influenced by recurring hypoxia and changes in organic matter fluxes. This makes the island an important site to study the influence of orbital-driven climate changes and tectonic-induced vertical motions on the marine benthic ecosystems in near-coastal areas at local and regional scales. We investigated the Early and Late Pleistocene sediment sections at Agathi Beach and Lardos, located on the middle-eastern coast of the island. Our results show variations in oxygen and food levels at the sea floor, including transient phases of enhanced fresh-water and nutrient input to near-coastal environments. These phases occurred at times of Northern Hemisphere summer insolation maxima, simultaneously to the formation of sapropels in the deep-sea basins of the eastern Mediterranean Sea. The application of a benthic foraminiferal transfer function revealed that both sections were influenced by tectonic-driven long-term and short-term vertical motions with higher rates than expected on the island of Rhodes. While Agathi Beach underwent two short-term cycles of uplift and subsidence, Lardos indicates at least three cycles with average rates of vertical motion as high as 8.6 mm/a.