Geophysical site survey for drilling into a sedimented shallow-water hydrothermal system
Final Report Abstract
Hydroacoustic survey work was conducted in Paleochori Bay in the southern part of the island of Milos, where venting of gas and hot water had been documented in prior studies. The survey aimed to establish lateral variability in the thickness of marine sediments on top of the faulted volcanic and metamorphic basement. The survey results were intended to be merged with geochemical data to test the hypothesis that fluid-mineral reactions within the sediments affect the composition of the effluent gases and solutions. The survey data was also planned to be used as a guide for site selection in potential scientific drilling endeavors. The funds were used to deploy a sub-bottom profiler from a rented boat and process the survey data. The survey worked, but the nature of the sediments (poorly sorted, commonly sandy to pebbly) and the abundance of seagrass or gas discharge negatively affected the data quality, and hence, the sediment-basement interface could not be reliably picked, nor could faults in the crystalline basement be identified in the hydroacoustic survey data.
