UC Santa Cruz

Escanaba Trough, located on the Southern segment of the Gorda Ridge, is a mid-ocean spreading center filled with turbidites from the West Coast of North America. The high contrast in density between the sediment that fills the trough and the minerals that precipitate from hydrothermal fluid provide ideal conditions for using physical methods to determine the lateral extent of hydrothermal mineralization on the seafloor. This study reports results from sediment and rock sampling and analysis to evaluate the nature and spatial (surface) extent of hydrothermal influence in recovered materials. X-ray computed tomography (CT) scanning of push cores taken at intervals moving from the edge of vent sites to the distal seafloor shows that sediments primarily composed of hydrothermal minerals are constrained to within approximately 20 m of vent sites at seven of eight sites. However, positive europium anomalies are observed for every sediment sample taken at Escanaba Trough, suggesting hydrothermal influence is widespread throughout Escanaba Trough.