Late Holocene Sedimentation Processes Along the Arabian Gulf Coast in the Juhail Area, Saudi Arabia

摘要

The study was designed to demonstrate that sedimentation processes at the Saudi Arabian Gulf Coast are different from the ones observed at the Trucial Coast (United Arab Emirates). Terrestrial, basically aeo-lian sedimentation and marine carbonate sedimentation obviously changed according to Holocene sea level changes, which were described by Fryberger et al. (1983) in the Dhahran area. Recent accumulation is dominated by terrestrial aeolian processes. Cyanobacteria, that are abundant in the intertidal flats, were discovered below about 70cm of terrestrial sediments in extensive sabkhas in a distance of more than two kilometers landward of the intertidal zone. ~(14)C dating of the cyanobacteria provided an age of not more than 700 years. Sedimentation characteristics indicate a significant change in sedimentation processes from marine to aeolian accumulation of terrestrial quartzose dune sand 700 years ago. Progradation at rates of more than three meters per year implies a considerable sand source as well as sand movement. Our study data suggest that a reduction in vegetation cover probably caused this development. Strong winds moved sandy substrate in southern to southeastern directions where it finally accumulated in the intertidal zone.