.... A syndepositional stage of microbial calcification was penecontemporaneous with biochemical dolomitization and followed by microbial diagenetic sulfate reduction of pore waters. The fenestral fabrics of the mats were the major channels of transport of cement-forming substances and the only channels that governed...

... observations upon which it is based are questioned. An assessment of implications for stromatolite biostratigraphy is presented in Knoll and Semikhatov (1998) . Geochemical conditions that were highly conducive to early synsedimentary calcification, and led to exceptional preservation, are a possible...

... resurgence, as Calner (2005) suggests. However, in addition to biotic competition, environmental factors also are likely to have influenced the secular abundance of microbial carbonates. Seawater chemistry is particularly important in this respect through its effect on the synsedimentary lithification...

... organisms, and spontaneous whitings from either abiotic precipitation or calcification of suspended picoplankton and organic matter. The styles of occurrence of micrite- walled tubes referred to Girvanella in lower Paleozoic limestones argue that occasional permineralization of mucilaginous sheaths...

...Fritz Neuweiler; Isabelle Daoust; Pierre-André Bourque; David J. Burdige Abstract Organic colloids are involved in the early calcification of the modern siliceous sponge Spheciospongia vesparium (Lamarck, 1815) from the Great Bahama Bank. Electron microscopy and in situ fluorescence...

... the Proterozoic and a significant part of the Archean. Despite their thinness, synsedimentary formation and coeval calcification of the veneers would have initiated early lithification, promoting stabilization of the deposits and thus enhancing sediment accretion. Little has been known until now about...

... features—abrasion, boring, calcification, encrustation, fragmentation, and dissolution—were recorded using (1) examination of loose grains belonging to the sand-size fraction, and (2) point counting in thin sections produced from sediment samples. Proportions of different grain types were not correlated...

... ‰), indicating postdepositional modifications. Early diagenetic calcification of microbial deposits promoted the formation of growth cavities and borings rimmed with marine fibrous and prismatic calcite cement. Some of the voids remained open and provided pathways for fluids during later diagenesis...

... with consideration of mound geometry and microfabric provide intriguing evidence for a marine benthic source of the NOM. The deep-water isolation of these mounds implies that near-surface mineral authigenesis is promoted within the mounds. In terms of fabric, the synsedimentary calcification of sponge soft tissue...

... mechanisms of the Anticosti buildups were the results of marine cement precipitation near the sea floor for the fenestrate cementstone facies, and of early calcification of sponge-derived organic matter (organogenic lithification) within the sediment for the crinoid and fenestrate bryozoan hash mudstone...

... to 2 m in diameter, were also found in the upper section of the Ust’-Yudoma Formation along the Dzhanda River (right tributary of the Aldan) [ 26 ], and stromatolites of diverse configurations were encountered in the section below ( Fig. 4 ). The onset of large-scale calcification of algae predated...

... or Girvanella formed through either in vivo sheath impregnation ( Riding 2000 ; Arp et al. 2001 ) or post-mortem degradative sheath calcification ( Chafetz and Buczynski 1992 ; Turner et al. 2000 ; Pratt 2001 ; Riding 2006 ), or both, which would account for the variable style of preservation...

... carbonates were deposited (abiotically, or by metazoan-controlled calcification, or microbially-induced calcification), because those sediments may record not only short-term global events, but also widespread secular fluctuations in oceanic conditions beyond the erathemic boundary. This paper documents...

... micrite, as described by Bathurst. However, the algae also produce micrite envelopes outside grains by the calcification (cementation) of exposed dead endolithic filaments, a process which reduces intergranular porosity. Algal filaments grow through the micrite envelopes into intergranular pores, and live...

... morphology that can be irrefutably tied to a biogenic, inorganic, or combined biogenic-inorganic origin. There are, however, clues suggesting that the mesoclots are due to calcification of microorganism, probably cyanobacteria, and that the nature of the mesoclots ( Fig. 5 ) is not the result of totally...

... contrast, micrite coatings (cortices) are often preserved whereas the remaining aragonitic grains become dissolved. This dissolution results in high-porosity moldic limestones, often with delicately preserved micrite rims ( Friedman 1964 ; Bathurst 1966 ). Constructive calcification resulting from...

... that calcify part of their thalli and gyrogonites. Their biocalcification belongs to the extracellular type since it occurs inside the cell wall but outside the cytoplasm where organic matter (OM) acts as nuclei for Ca precipitation, a process named extracytoplasmic calcification ( Leitch 1991 ). The Ca-rich...

.... Instead, these two buildup-constructing genera radiate out from a central bouquet, possibly maximizing exposure to light rather than current. Due to their growth habit, extensive calcification, presumed oligotrophic environment, and pseudocoloniality, these two genera may have harbored photosymbionts...

... microboring, recrystallization, biofilm-related calcification, and dissolution. Grain susceptibility to each process is highly variable and influenced by mineralogy and skeletal structure. Coral fragments, for example, are most susceptible to the effects of microboring, whereas Halimeda plates are most...

... of brachiopods ( Hindella terebratulina in the lower part, Brevilamnulella kjerulfi in the upper parts), and which often are strongly altered by synsedimentary subaerial exposure ( Kröger et al. 2015 ). The top of the formation is defined at the major unconformity, which marks the base of the Glisstjärn...