A SEM and EDS Study of Manganese Nodules From the Northwest Atlantic

• Published in: Proceedings, annual meeting, Electron Microscopy Society of America
• Main Authors: Berry, V.K., Addy, S.K.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1981
• Subjects: General Medicine; Northwest Atlantic
• Online Access: http://dx.doi.org/10.1017/s0424820100097417; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0424820100097417

In a recent study of micronodules from the red clay province on the Abyssal Hills of Northwest Atlantic the micronodules were generally found to be bo-tryoidal clusters of concentric “ compact balls” fused in a coarse grained friable “Porous Cement.” It is believed that the compact balls which have higher Mn content than Fe, were formed by direct precipitation of ferromanganese oxide from the sea water at the sediment water interface and later joined with each other by a porous cement containing higher Fe and clay content. In the present studies two groups of nodule samples were used to compare their morphology and chemistry with the micronodule samples studied earlier. The samples from one group were collected from the Abyssal Hills-the red clay area and the second group from the Bermuda High-the foraminiferal clay area. The location and the depths of the four samples studied here are (1)28°46.2'N, 60°20.5'W, 5359 meters, (2)27°01.5'N, 58°49.8'W, 5087 meters, (3)31°16.07N, 67°37.99'W, 4590 meters and (4)same as (3) but different location in the vicinity. The nodule samples varied in size from ½” to 3” in diameter. The sample pieces were mounted on a carbon planchet with silver paste and sputtered with ∼200Å of AU/Pd, before transferring to the microscope. Both the outside surface of the nodules and the inside surface (after cutting open with a sharp blade) were examined in JEOL JSM-35 SEM fitted with Nuclear Semiconductor Si (Li) x-ray detector and Tracor Northern NS-880 Analysis System. The microscope was operated at 25kV acc. voltage in the secondary electron emission mode. The x-ray spectra were taken in 0-10 keV range with total count time of 100 sec.