... by the calcimicrobe Renalcis with subordinate Epiphyton and Girvanella . Scanning electron microscopy of the dark micrite of the Renalcis chambers showed amorphous translucent sheet-like structures interpreted as extracellular polymeric substances, closely associated with organominerals including nanoglobules...

... contain dense accumulations of large (10 × 300 μ m) filamentous Girvanella microfossils. Many laminae are not spherical, often occurring with one flat side opposite a conical peak. Up to six generations of conical geometry are present, with each cone rotated with respect to the previous peak. We...

... components and siliceous sponges co-occur. The maze-like structures consist of microbial components such as microstromatolites, Girvanella , and Renalcis -like forms, as well as sponge spicule networks, whereas lime mud and bioclasts occupy the space between the structures. The maze-like structures developed...

... microcoprolithes are locally superabundant ( Fig. 1A ), and calcified sheaths of filamentous, exclusively phototrophic cyanobacteria ( Girvanella , Fig. 1C ) indicate a depositional depth within the photic zone. Figure 1. Features of Tropic Shale (Western Interior Seaway, United States) seep carbonates...

... with encrusting Girvanella, eocrinoid plates, rhynchonelliformean brachiopod valves and subordinate hyoliths and trilobites in tempestite shell beds; these beds underwent synsedimentary cementation on the seafloor to form hardgrounds. In the succeeding, higher energy interval, a complex of metre-scale bioherms...

... that a considerable part of Paleozoic carbonate mud may have been derived from disintegrated micrite tubes considered to have been formed by calcified cyanobacteria. Such micritic tubes from many Paleozoic and Mesozoic carbonate rocks are known as Girvanella -type microfossils; most Proterozoic examples are less...

... 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...

..., northwestern Australia, demonstrate, however, that a novel reef ecology was established in the immediate aftermath of the Frasnian-Famennian mass extinction. Here, diverse calcimicrobes (including Rothpletzella spp., Shuguria spp., Ortonella , and Girvanella ), together with bryozoans, brachiopods...

.... occasionally show calcium deposited as thin horizontal strips ( Plate 1 , figs. 6, 10); similar stripped sheaths were observed in thin sections many times [ 16 ]. Calcareous sheaths of Renalcis Vologd., Epiphyton Born., Proaulopora Vologd., Subtifloria Masl., Girvanella Nich. Et Ether., Obruchevella...

... study. Detailed lithofacies analysis of the Middle Cambrian Maryville Limestone along a shelf-to-basin depositional transect reveals that the shelf evolved from a gently basinward-sloping ramp to a rimmed platform fringed with steeper slopes. Cyanobacterial buildups ( Renalcis-Girvanella ) dominated...

... of three different calcareous microfossils. A tubule-thread microfossil, analogous to the calcimicrobe Girvanella in Paleozoic reefs, formed laminar-reticulate structures, like those in Ordovician bioherms. A clotted to saccate microfossil, comparable morphologically to Paleozoic Renalcis , constructed...

...Mario Coniglio; Noel P. James Abstract Calcified algae are important elements of deep-water carbonate sediments in the Cow Head Group. Large algal boundstone boulders in debris-flow conglomerates consist of Girvanella sheets and arborescent clusters of Epiphyton . Silt- and sand-sized particles...

...-water clasts within both conglomerates and deep-water slope sediments. Large boulders contain sheets of Girvanella and arborescent clusters of Epiphyton , but only Girvanella as intraclasts, rafts of intertwined tubules, single tubules, and oncolites can be distinguished in calcarenites. Preservation...

... masses into foreslope-slope settings. Generation 3 geopetals of dolomite silt, which rests on earlier calcite cement and is postdated by saddle dolomite, formed during deep burial and deformation of the sequence. Reefal blocks are composed of Epiphyton and Girvanella boundstone, thrombolites...