Poster Number 16
See more from this Division: Joint Sessions
See more from this Session: Biologically Induced Dissolution and Precipitation of Minerals in Soils and Sediments (Posters)
Abstract:
Nodules consisted of primary mineral grains cemented by iron oxides, clay minerals and fungal hyphae and exhibited no concentric layering. Nodules examined by SEM were found to contain areas of high iron content that include spherical vesicles or coccoidal features approximately 5 microns in diameter. The vesicles were lined with fungal hyphae which also contained or were replaced by iron. The areas of high iron tended to wrap around primary mineral grains, and fungal tunneling of mineral grains was common, especially in the nodules from older terraces. Fungal hyphae occupying tunnels within primary mineral grains also had elevated iron content. This observation supports the hypothesis that the iron is actively precipitated by the fungi. Many thin sectioned nodules contain vesicles in oval structures which have been tentatively correlated to micro-colonial fungi (MCF). Previously, MCF have only been associated with desert varnish.
See more from this Division: Joint Sessions
See more from this Session: Biologically Induced Dissolution and Precipitation of Minerals in Soils and Sediments (Posters)