Last interglacial sea level high-stand deduced from well-preserved abrasive notches exposed on the Galilee coast of northern Israel

By: Sisma-Ventura G., Sivan D., Shtienberg G., Bialik O.M., Filin S., Greenbaum N.
Published in: Palaeogeography, Palaeoclimatology, Palaeoecology
SDGs : SDG 14  |  Units: Social Sciences  | Time: 2017 |  Link
Description: This study investigates the morphometry and structure of abrasive notches exposed along the tectonically-stable, micro-t idal Galilee coast, Israel, south-eastern Mediterranean, since they can serve as past sea-level indicators. The characteristics of the notches, height (H), vertex (D) – distance of maximum retreat point from cliff face, height of retreat point from the floor and roof (HF and HR, respectively), etc., were surveyed using LIDAR and a digital laser rangefinder, and elevations were measured using DGPS. Rock resistance was measured by Schmidt hammer tests, which show that the most developed and best preserved notches were formed within the more resistant host rocks of the Cenomanian chalk and the Pleistocene aeolianite sandstone. The elevations of the abrasive floors of the exposed notches indicated a sea level slightly higher than at present at the beginning of MIS5e, with an upper limit between + 0.5 and + 0.75 m. The morphometry of the MIS5e notches, which are larger than modern notches in the study area, suggests mechanical erosion by broken waves, where an energetic wave-dominant sea batters a sheltered coastal cliff. Two sub-units of MIS5e (the Yasaf Mb.) were deposited within the notches: (a) a conglomerate containing the diagnostic fossil Strombus bubonius which was found on the notch floor, and (b) a younger bioclastic sandstone sub-unit which fills and covers parts of the notches. These unique field relationships link the formation of the notches to the beginning of MIS5e, indicating an erosive phase which parallels large-scale MIS5e sea level evidence, suggesting relatively long stand-stills at an elevation of about + 1 m. The early MIS5e erosive phase was followed by a depositional phase during the later stage of MIS5e. © 2017