Chemical composition of crust from R/V Dmitry Mendeleev station 1052. Comaprison with similar hydrothermal deposits

The manganese crust was retrieved from station 1052 during the 14th cruise of the R/V Dmitry Mendeleev. The station is located in Hess Deep in the axis of the Galapagos Spreading Center, just east of its junction with the East Pacific Rise. It consists of 16 mm of ferromanganese material encrusting fresh basaltic glass (see illustration). Analyses were performed by instrumental neutron activation analysis except for Cu and Ni which were determined by atomic absorption. Microprobe analyses of the underlying glass reveal typical ocean theolitic composition with low alkalis and a SiO2 content of about 50%. They are compared to other published data from the Galapagos Spreading Center, the Mid-Atlantic Ridge and the flank of the East Pacific Rise.