... in the western Arabian Sea have a high nitrate to iron ratio, such that toward the end of the upwelling season primary productivity becomes iron limited. Under iron stress, diatoms consume more silicate when normalised to nitrate, leading to a community shift to smaller taxa offshore. The consequent offshore...

... matter with higher quality than pyritization or iron-oxide mineralization. Additionally, some guidelines can be proposed concerning the body parts and taxa that can be compared, and for what purpose, when contrasting mineralized and keroginized soft-bodied deposits. Compared with pyritization...

... sections show microcrystalline carbonate-fluoride-bearing calcium phosphate with small amounts of calcium replaced in the crystal lattice. Optical microscopy and EMP investigations show that iron and manganese oxides are responsible for elevated iron and manganese concentrations in the bulk mass...

..., New Zealand, are preserved through replacement and/or encrustation. Organic matter is typically absent, and examples of sheaths being partly replaced or coated by other minerals, such as iron oxide, have not yet been recognized. Accordingly, the cellular-level information needed for microbe...

... aluminosilicate minerals, partly secondarily silicified, cover the exterior and interior shell surfaces. Occasionally, early diagenetic pyrite crystals, now oxidized to iron hydroxides, filled shell cavities forming internal moulds and rarely replaced the bivalve shell. The poor preservation of the bivalves...

... with preserved details, and whole-body trilobite preservations, often have iron (Fe) oxide halos that resulted from a biochemical cascade including bioimmuration, decomposition gas anoxia, Fe-sulfide crystallization, and Fe oxidation. Preservation of soft tissue is also partly attributable to the well-sorted...

... to iron depletion. Subsequently, rapid ventilation of oceanic basins occurred, during which direct aerobic oxidation of sulphide into sulphate predominated in bottom waters and even surface sediments with minimal fractionation. This oxygenation was probably induced by intensive climatic cooling...

...Sebastien Clausen; Andrew B. Smith Abstract Echinoderm skeletal debris from the Early–Middle Cambrian boundary Micmacca Breccia of Morocco includes the oldest known holomeric columnals. The original calcite of these ossicles is coated and replaced by iron oxides, occasionally overlain by a late...

... decade, and characterize their preservation. Soft internal cellular organs/tissues, such as digestive tracts and glands, cardiovascular systems, nervous systems, and musculature, are predominantly preserved as carbonaceous compressions, in contrast to their iron oxide–rich preservation in the EB. Our...

... μm. L: SE image showing common habit on several taxa where iron oxides are coated with clay minerals; scale represents 5 μm ...

... potentially representing multiple generations of authigenesis. Mg- and Fe-rich clays, for example, commonly surround and are attached to K-rich aluminous clays ( Fig. 7 ). Rare iron oxides are not spatially associated with the fossils; they are not framboidal, mostly infill late-forming fractures...

.... The appendages, eye and dorsal exoskeleton of L. deletres have been analysed for their mineralogy and chemical composition. The appendages are preserved as a coating of iron oxides after pyrite (see Gabbott et al. 2004 ; Zhu et al. 2005 ), composed of a thin veneer of anhedral to subhedral microcrystals...

... consisting of millimetre-scale laminae with carbonate and clay components. ( d ) Transmitted light micrograph of thin section of fossil-bearing lithology from c. 210 m below the top of the Weeks Formation. Clay-dominated intervals appear dark and carbonate-dominated intervals appear bright. Iron oxide...

..., fibrous meshwork, probably iron (Fe III) oxide-hydroxides, which likely originated from microbial or fungal activity ( Fig. 3.4 ). Foraminifers were rare (an average of 0.5–2.5 specimen/cm 2 ); their highest abundances (6 specimens/cm 2 ) were in the lower and middle Aalenian (samples 2, 3, 6...

... ( Bezerra et al., 2018 ), recent investigations on 138 fossil insects suggest that the vast majority of fossils were initially preserved in pyrite and subsequently oxidized into iron oxides/hydroxides ( Figs. 1F and 1G ; Bezerra et al., 2023 ). The high reactivity of the early diagenetic environment...

... to deplete the lowermost greenish gray channel-filling deposit (Gr of Duchaufour, 1982 ; PiPujol and Buurman, 1994 ); percolating oxygen-rich surface water oxidized iron along cracks in the upper red and gray fill layer, conditions that contrast sharply with the typical vertic processes that developed...

..., 2.6a, 2.6b) and most of the scalids are also preserved in slight relief ( Fig. 2 .1a–2.3). Cuticle and cuticular structures are highly mineralized and preserved in a rusty color, caused by a concentration of iron oxides ( Fig. 3 .1, 3.4–3.9). Elemental mapping (SEM EDX) also reveals that the dark color...

... minerals, sulfate, nitrate, and ferric iron from iron oxides, as well as strong oxidants such as O 2 (e.g., Adam and Perner 2018 ). Hence, molecular hydrogen is capable of fueling the energy metabolism of populations inhabiting both anoxic and oxic ecosystems. The large diversity of biochemically...

... the Data Repository). Raman analysis demonstrates that there was a degree of homogeneity across the host rock and the 14 Sirius Passet fossil specimens, with all spectra exhibiting a strong carbon signal (with the exception of some point spectra directed at the iron oxide and oxyhydroxide coatings...