East Pacific Rise Near 13°N: Geology of New Hydrothermal Fields

Abundant massive sulfide deposits are present at the crest of the East Pacific Rise near 13 ° North, where the opening rate is about 12 centimeters per year. Large manganese and helium-3 anomalies in seawater samples, evidence of intense present-day activity of hydrothermal springs, indicate that sulfides are still being produced along this segment of the rise. Massive sulfides also occur on adjacent off-axis seamounts .