In-<I>Situ</I> growth of Authigenic Minerals and Micronodules in Some Pelagic Sediments from the Central Pacific

Abstract

Sediment samples from NS Transect in the Central Pecific Ocean, comprising the Areas C. D. F and G investigated with the help of scanning electron microscopy reveal in-situ formation of several authigenic minerals within pelagic sediments, which affect their surface texture and morphology. Zeolite crystals developed in-situ are noted in the siliceous ooze in the north equatorial Pacific (Area C). Micronodules with well developed initial growth lines, formed authigenically are commonly observed in the siliceous debris-rich calcareous ooze of south equatorial Peciflc (Area F). Quartz and feldspars of detrital origin are also found in the sediment. Dissolution of biogenic debris is noted in them. However. undissolved radiolarian oozes are common particularly in the sediments from south Pacific. Authigenic phillipsite needles are identified in the sediments from Area G which falls within the Marquesas Fracture Zone.