• Gaye Bayracki
  • National Oceanography Centre (NOC) Southampton
  • United Kingdom

Ultramafic-hosted seafloor massive sulphide (μSMS) deposits are found in magma-poor ridges, where lower-crust and upper-mantle ultramafic rocks are exhumed by ‘detachment’ faults forming oceanic core complexes (OCCs). The μSMS deposits are estimated to contain larger amounts of Cu and Zn than the active SMS deposits at volcanic plate margins, and to have sub-seafloor ore bodies where hydrothermal fluids have mixed with serpentinising fluids. The Semyenov Hydrothermal Field, located on the Mid-Atlantic Ridge at 13°30’N, hosts five μSMS deposits and, therefore, is an ideal laboratory to study the mineral, chemical and physical controls on the formation and evolution of μSMS deposits. Studying the physical properties of μSMS deposits and quantifying the extent of sub-seafloor mineralisation using seismic techniques is challenging due to their small (few 100’s m) size, burial beneath shallow sediments, within a hard-rock host, and in a deep sea environment. In this talk we discuss the short comings of conventional ship-towed airgun seismic surveys in constraining such targets and develop new strategies such as “inverse vertical seismic profiling” and “borehole seismic” imaging using short-offset “seismic-while-drilling” techniques and an ROV mounted deep-towed high-frequency source to overcome these challenges.

About the speaker

Bayrakci made her BEng in the University of Istanbul followed by an MRes and a PhD in Institut de Physique du Globe de Paris (IPGP). She worked as a post-doctoral researcher in IPGP (Fr), IFREMER (Fr) and the University of Southampton (UK). She is currently working as a Marine seismologist in National Oceanography Centre (Southampton, UK). Her research focusses on the seismic expression of fluid flow.