Detection of Low-Temperature Hydrothermal Fluxes by Seawater Mg and Ca Anomalies
Stephanie de Villiers,
*
Bruce K. Nelson
Geochemical fluxes into and out of the ocean control its chemical
composition. Measurements of the magnesium (Mg) content of seawater, an
assumed "conservative" element in the ocean, reveal mid-depth Mg
depletions in the vicinity of the East Pacific Rise. The magnitude of
the anomalies suggests that fluxes associated with the low-temperature
circulation of seawater through axial mid-ocean ridge systems are much
larger than the high-temperature axial component. A higher total axial
hydrothermal flux provides a mechanism that simultaneously satisfies
the mass balance requirement of several major seawater constituents.
Geological Sciences Department, Box 35-1310, University of
Washington, Seattle, WA 98195-1310, USA.
*
Present address: Department of Geological Sciences, University
of Cape Town, Rondebosch 7701, South Africa. E-mail:
steph{at}cigc.uct.ac.za
