Accession Number : AD0764616

Title :   Occurrence and Alteration of Clay Minerals in the Caribbean Sea,

Corporate Author : TEXAS A AND M UNIV COLLEGE STATION DEPT OF OCEANOGRAPHY

Personal Author(s) : Johnson,Charles N.

Report Date : MAY 1973

Pagination or Media Count : 124

Abstract : Both vertical and horizontal trends in clay mineralogy are examined in six cores from the southwestern and central Caribbean. An additional sample is analyzed for clay mineralogy from the Magdalena River in Colombia. X-ray diffraction, differential thermal analysis, infrared spectroscopy, and electron micrography are used to determine the clay mineralogy. Montmorillonite, vermiculite, mica, kaolinite, chlorite, halloysite, allophane, and gibbsite are identified by the above methods. Techniques of sample preparation are examined and proposed. The use of samples that have been allowed to dry is cautioned against for marine clay analysis. Control and monitoring of pH during the preparation procedures is also proposed. Alteration of clay minerals in the marine environment is examined by noting the trends between cores for various selected ratios. The ratios are derived from the peak intensity and not from computed percentages. Ratios derived from percentage computations would be influenced by other clay mineral levels. Diagenesis of a clay mineral is defined as the alteration of the mineral in such a way that it loses its identifying characteristics. (Modified author abstract)

Descriptors :   (*CLAY MINERALS, *CARIBBEAN SEA), OCEAN BOTTOM SAMPLING, THERMAL ANALYSIS, X RAY DIFFRACTION, INFRARED SPECTROSCOPY, ELECTRON MICROSCOPY, KAOLINITE, MONTMORILLONITE, MICA

Subject Categories : Physical and Dynamic Oceanography
      Geology, Geochemistry and Mineralogy

Distribution Statement : APPROVED FOR PUBLIC RELEASE