Paleo ocean floor

A hydrothermal vent is a fissure on the seafloor from which geothermally heated water discharges. Hydrothermal vents are commonly found near volcanically active places, areas where tectonic plates are moving apart at spreading centers, ocean basins, and hotspots. Hydrothermal deposits are rocks and mineral ore deposits formed by the action of hydrothermal vents.

• http://en.wikipedia.org/wiki/Hydrothermal vent
• https://commons.wikimedia.org/wiki/File:Paleo-seafloor_black_smoker_rocks_in_siderite_iron-formation_(Helen_Iron-Formation,_Neoarchean,_2696-2749_Ma;_Sir_James_Pit,_Eleanor_Iron_Range,_Ontario,_Canada)_3_(48069947697).jpg