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CH3041
HYDROTHERMALS
• The basaltic ocean crust is replaced at
Marine Oceanic Ridges (MOR) by magma
from shallow magma chambers.
•A convection cell is set up where cool
ocean water descends into the fissured
basaltic crust and the heated chemically
altered hot water ascends. “hydrothermal”
• A sulphidic plume (Fe, Zn, Pb, Cu) issues
forth from “black smokers” at 200 - 400oC.
• These hydrothermal cells affect the ion
budgets of Mg, Si, K, Ca, Na and SO42-.