Previous experiments have proved that thermodynamically unstable calcium carbonate vaterite can exist for long periods in the yolk sac of a pigeon embryo. The aim of this article was to demonstrate the effect of in vitro mineralization of yolk sac fluid on calcium carbonate by direct precipitation. Experiments were conducted using pigeon yolk sac fluid and using lecithin extracted from pigeon y...

The Infra Krol Formation and overlying Krol Group constitute a thick (< 2 km), carbonate-rich succession of terminal Proterozoic age that crops out in a series of doubly plunging synclines in the Lesser Himalaya of northern India. The rocks include 18 carbonate and siliciclastic facies, which are grouped into eight facies associations: (1) deep subtidal; (2) shallow subtidal; (3) sand shoal; (4...

The sedimentary record reveals first-order changes in the locus of carbonate precipitation through time, documented in the decreasing abundance of carbonate precipitation on the seafloor. This pattern is most clearly recorded by the occurrence of seafloor carbonate crystal fans (bladed aragonite pseudomorphs neomorphosed to calcite or dolomite), which have a distinct temporal distribution, ubiq...

Calcium carbonate is an important component in exoskeletons of many organisms. The synthesis of calcium carbonate was performed by mixing dimethyl carbonate and an aqueous solution of calcium chloride dihydrate. The precipitation product was characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrar...

The complexation of Cm(III) with the recombinant N-lobe of human serum transferrin (hTf/2N) is investigated in the pH range from 4.0 to 11.0 using TRLFS. At pH ≥ 7.4 a Cm(III) hTf/2N species is formed with Cm(III) bound at the Fe(III) binding site. The results are compared with Cm(III) transferrin interaction at the C-lobe and indicate the similarity of the coordination environment of the C- an...

The Upper Jurassic carbonates of the eastern part of the Kopet-Dagh Basin, with thickness of 470 m, are the major gas-bearing reservoir in NE Iran. The objectives of this study are recognition of diagenetic history and estimation of porosity related to dolomitization. Based on field and laboratory study, four carbonate facies associations have been identified at the Mazdavand outcrop. Most of t...

Wettability alteration is an important method for increasing oil recovery from oil-wet carbonate reservoirs. Chemical agents like surfactants are known as wettability modifiers in carbonate systems. Oil can be recovered from initially oil-wet carbonate reservoirs by wettability alteration from oil-wet to water-wet condition with adding dilute surfactant and electrolyte solutions. This paper inv...

We have studied the formation and carried out an in vivo evaluation of carbonate apatite (CO3-Ap) and CO3-Ap/CaCO3 composite coatings on titanium substrates using the thermal substrate method. The coatings were formed on commercial pure titanium rods (diameter = 2mm, length = 5mm) and plates (thickness = 0.3mm) by the thermal substrate method in an aqueous solution that contained Ca(H2PO4)2, Ca...

Carbonate concretions occur in sedimentary rocks of widely varying geological ages throughout the world. Many of these concretions are isolated spheres, centered on fossils. The formation of such concretions has been variously explained by diffusion of inorganic carbon and organic matter in buried marine sediments. However, details of the syn-depositional chemical processes by which the isolate...