Keynote Speaker
Prof. (Emeritus) Yossi Mart
Recanati Institute of Maritime Studies, University of Haifa, IsraelSpeech Title: Sealevel Variations in the First Millennium and Their Climatic Significance: Caesarea Maritima in Coastal Israel
Abstract: Climate changes affected planet Earth repeatedly from its earliest evolutionary stages, but the closure of the Mid-America waterway between the equatorial Atlantic and Pacific Oceans, which marks the beginning of the Pleistocene, cooled the Pacific Ocean and enhanced the Quaternary climatic significance of Earth orbital variations. A prime proxy of such climate change is the level of the global oceanic system, which rises during warmer climates, when some continental ice melts, and drops at colder times due the excessive accumulation of ice on land. The advantage of reconstructing variable sealevels is by their global uniformity, but, on the other hand, sea levels are not simple to measure precisely even when the disruptions of the daily tides are overcome. Landmass may rise due to neotectonic activity and subside b because of either sedimentary loads or structural changes. Caesarea in coastal Israel was a large port and administrative city during Roman, Byzantine, Islamic and Crusaders; rules from the 1st to the 13th Centuries. It was inaugurated on at 10 BC and destroyed in 1265 AD, and a high aqueduct, built to serve the city from its inception, still stand tall. Surveying of that grand structure shows that its gradient is 0.05%, as recommended by Vitruvius in his 1st Century BC handbook on civil engineering, De Architectura. That gradient indicates that the coastal plain of northern Israel, transected by that aqueduct, has been tectonically stable during the last two millennia. Furthermore, structural subsidence, triggered by accumulation of fluvial sediments does not take place in Caesarea. Consequently, geo-archaeological evidence of past sea levels are globally significant.
Three dated archaeological constructions indicate historic sea levels,
*A jetty used to load and download ships during Crusaders; times, in the 12th – 13th Centuries, is inundated at present by more than 50 cm of seawater.
*Seventh to Ninth Centuries water wells, where fresh water of the coastal aquifer float on seawater, suggest that sea level was higher than the present by circa 0.75 cm then.
*The swimming pool at the royal palace in Caesarea, excavated in the coastal Pleistocene sandstone, can become operational at present after some minor cleaning.
Consequently, it seems that the climate of some 2000 ago was similar to the present; it was warmer than the present some 1200 years ago, during the Mediaeval warm period, and colder ca. 800 years ago, at the beginning of the Little Ice Age.
Biography: Prof. (emeritus) Yossi Mart, University of Haifa, Israel. I received my B.Sc. and M.Sc. degrees in Geology from the Hebrew University in Jerusalem and a PhD in geological oceanography from Texas A&M University in College Station, Texas. I worked as a Senior Scientist in the Oceanographic Institute in Haifa, Joined Haifa University in1985, and I was a visiting professor in the Universities of Rennes, France, in Columbia University in New York, and in Uppsala in Sweden. My experience includes being chief scientist at numerous seismic reflection cruises on board R/V Shikmona A and B, Etziona, Hermona, and Mediterranean Explorer in the Mediterranean, Black and Red Seas, and participated in several French and American research cruises in the Atlantic Ocean and the Mediterranean Sea. I dived with French submersible “Cyana” to the floor of the Bay of Biscay (2650 m) and the western Mediterranean (1800) off Toulon. I participated in the drilling campaign of the scientific research vessel “JOIDES Resolution” in the eastern Mediterranean. I applied analog modeling techniques at the laboratories of the universities of Rennes in France and Uppsala in Sweden to decipher problems associated with rifting and with subduction. I wrote 89 scientific papers (https://www.researchgate.net/profile/Yossi-Mart), as well as 2 popular books and several papers in Hebrew. My present research focuses on various phenomena associated with oceanic subduction, with continental break-up and rifting, with the sedimentological regime in the SE Mediterranean basin during the Oligo-Miocene, and with recent and sub-recent climate changes and their subsequent sealevel variations.