Accession Number : AD0701713
Title : TRACE ELEMENT DISTRIBUTION IN SEDIMENTS OF THE MID-ATLANTIC RIDGE.
Descriptive Note : Doctoral thesis,
Corporate Author : MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF EARTH AND PLANETARY SCIENCES
Personal Author(s) : Copeland,Richard A.
Report Date : JAN 1970
Pagination or Media Count : 105
Abstract : Several sediments from the flank of the Mid-Atlantic Ridge were analyzed for trace elements by neutron activation analysis. It was found that high concentrations of iron, cobalt, manganese and strontium are associated as coatings on the 37-73 micron size fraction of foraminiferal calcite. The metals appear to be derived from the decomposition of clay minerals associated with the carbonate. Strontium appears to be a contaminant introduced by partial solution of a non-carbonate mineral. Rare earth analysis indicated that an established rare earth distribution is stable during the conversion of palagonite to greenstone and during the conversion of iron-rich chlorite to magnesium-rich chlorite. The fine chlorite in the sediment appears to be local in origin while the montmorillonite appears continental. Amorphous sediments from the immediate vicinity appear to be a product of a local ash flow. They were all enriched in rare earths compared to local basalts. This enrichment is probably due to an enrichment of rare earths in the parent magma compared to basalts but may in part represent the result of selective complexation of rare earths by anions in sea water. (Author)
Descriptors : (*MARINE GEOLOGY, ATLANTIC OCEAN), (*OCEAN BOTTOM, MINERALS), SEDIMENTATION, IRON, COBALT, MANGANESE, STRONTIUM, CHLORITES, NEUTRON ACTIVATION, GEOCHEMISTRY, CALCITE, CARBONATES, X RAY DIFFRACTION, CLAY MINERALS, THESES
Subject Categories : Physical and Dynamic Oceanography
Geology, Geochemistry and Mineralogy
Distribution Statement : APPROVED FOR PUBLIC RELEASE