Calcitic nanofibres in soils and caves: a putative fungal contribution to carbonatogenesis - Tufas and Speleothems: Unravelling the Microbial and Physical Controls - page 231

Fig. 7. Hypothetical sketch recapitulating the potential processes of fungal organic matter decay and mineralization of
cell wall fibrous material. This model is based on observations, analysis, and interpretations given in this paper. The first
stage starts with a fungal hyphae or a group of hyphae forming a fungal strand. The cell wall is constituted by two main
layers, an amorphous one (on the top) and a fibrous one (at the bottom; for more details see Fig. 1). It is assumed that the
cell wall fibrous material is not decayed at the same rate than the amorphous material. When released in the soil
microenvironment, these nanofibres could act as template for calcite nucleation, eventually leading to calcitic
pseudomorphosis. The ultimate step is represented by possible reworking due to various processes (bioturbation, water
movements, cryoturbation, etc.). Nanofibres are often associated with other calcitic features, such as NFC, leading to the
complex microfabric observed in soil and cave deposits. O.M., organic matter.