During the recent field research on the Tirgan Formation in the west of Kopet-Dagh sedimentary basin, ammonite assemblages were obtained from the carbonate strata of this formation. This new finding is important for stratigraphical purpose. In this research, 3 genera belong to Heteroceras, Deshayesites and Cheloniceras? as well as one uncertain genus belongs to Turkmeniceras are determined. The...

Mollusks shell formation is mediated by matrix proteins and many of these proteins have been identified and characterized. However, the mechanisms of protein control remain unknown. Here, we report the ubiquitylation of matrix proteins in the prismatic layer of the pearl oyster, Pinctada fucata. The presence of ubiquitylated proteins in the prismatic layer of the shell was detected with a combi...

Removal of carbon through the precipitation and burial of calcium carbonate in marine sediments constitutes over 70% of the total carbon on Earth and is partitioned between coastal and pelagic zones. The precipitation of authigenic calcium carbonate in seawater, however, has been hotly debated because despite being in a supersaturated state, there is an absence of persistent precipitation. One ...

On continental margins, oxidation of methane-rich fluids from the sediment often leads to formation of authigenic carbonate pavements on the seafloor. The biogeochemical processes involved during this carbonate precipitation are increasingly understood, but little is known about the duration or mode of carbonate crust formation. Here, we report uranium and thorium concentrations and isotope com...

Impact of diagenesis on carbonate mound formation This thesis is devoted to define the parameters influencing cold-water coral growth and therefore carbonate mound development with a focus on the impact of diagenesis on mound sediments. The first part of this thesis (Chapters 2 to 4) discusses the distribution and growth history of carbonate mounds, the sedimentary processes leading to sediment...

Recent work has demonstrated that the dynamic interplay between silica and carbonate during co-precipitation can result in the self-assembly of unusual, highly complex crystal architectures with morphologies and textures resembling those typically displayed by biogenic minerals. These so-called biomorphs were shown to be composed of uniform elongated carbonate nanoparticles that are arranged ac...

A fundamental study of scale formation of calcium carbonate (CaCO3) for producing oil wells has been carried out. This article presents the study of the prediction of salt deposition in two different synthetic formation waters and investigates the effects of temperature and pressure on calcium carbonate precipitation. The dependence of the induction period of the precipitation of calcium carbon...

It is widely recognized that carbonic anhydrase (CA) participates in silicate weathering and carbonate formation. Nevertheless, it is still not known if the magnitude of the effect produced by CA on surface rock evolution changes or not. In this work, CA gene expression from Bacillus mucilaginosus and the effects of recombination protein on wollastonite dissolution and carbonate formation under...