A scanning electron microscope (SEM) image showed that the growth tip of the thin prismatic layer was covered by the periostracum, which was also where the initial formation of calcite crystals began. A cross-section containing the thin calcite crystals in the thin prismatic layer with the periostracum was made using a focused ion beam …

Authigenic low-magnesium calcite (LMC)—a mineral phase that should precipitate in calcite seas rather than today's aragonite sea—was recently discovered at the seafloor of the Gulf of Mexico (GoM) at water depths of 65 m (site SS296) and 189 m (site GC53). This study investigates the mineralogical, petrographic, and geochemical …

The formation of Mg-bearing calcite was interpreted as the following process: firstly, aragonite nuclei, formed owing to Mg ions at the initial stage of CaCO 3 crystallization, which was then transformed into calcite nuclei through a solid-to-solid process while their growth was inhibited by the adsorption of carboxylic acids (Wada et …

Calcite is the one of the most common minerals. It occurs in a great variety of shapes and colors, and it constitutes a major portion of many of the earth's rocks. Calcite belongs to the calcite group of minerals, a group …

This provides a good case study of the formation mechanism and migration of calcite cement in a closed diagenetic system, although few studies of these issues have been conducted. The aims of this study were to: (1) investigate the types and distribution of calcite cement in lacustrine sandstone reservoirs through mineralogical and …

Formation of Calcite. Calcite formation is a fascinating process that occurs both in geological environments and through biological activity. Its formation is essential in creating various geological structures and influencing natural processes. This mineral is primarily found in sedimentary rocks, where it plays a key role in the rock cycle.

The properties of calcite make it one of the most widely used minerals. It is used as a construction material, abrasive, agricultural soil treatment, construction aggregate, …

Calcite fibres, with a predominant subvertical c-axis orientation, exhibit a displacive growth in porous shales and a replacive growth at vein-limestone contacts. This study highlights the critical role …

Fluids have major roles in the Earth's crust: they can alter porosity and permeability, transport material, dissolve and precipitate minerals and interact with deformation (Connolly 2010; Laubach et al. 2019).Syn-tectonic calcite- or quartz-filled veins are common in low-grade metamorphic rocks in the upper and middle crust (Beach …

Although the hydrothermal influence on the formation of vein calcite is related to geological events specific to the Wrangellia Terrain, this study provides an alternative mechanism for the generation of fibrous calcite veins and demonstrates the local importance of hydrothermal input in the evolution of pore-water chemistry. I. …

Hence, formation of vaterite in the presence of DTPA at 150 °C could be due to two possibilities (i) by formation of new vaterite nuclei or (ii) by the transformation of existing calcite. Though second possibility seems to be violating the second law of thermodynamics, the formation of vaterite along with calcite at intermediate …

Field emission scanning electron microscopy (FESEM), two-dimensional X-ray diffraction (2D-XRD), and transmission electron microscopy coupled with selected area electron diffraction (TEM-SAED) analyses of the reactant/product textural relationship show that the thermal decomposition of Iceland spar single crystals according to the reaction CaCO …

Scenarios of the formation of calcite scaling: (a) linear decompression scenario in which calcite precipitation occurs only due to the solubility decrease associated with the linear pressure decrease of ca. 280 bar as the thermal water is pumped from the Malm aquifer to the surface. (b) Corrosion scenario in which calcite precipitation is ...

As an essential inorganic material, calcium carbonate (CaCO3) is one of the most abundant minerals in nature, whose preparation by the carbonation of calcium hydroxide [Ca(OH)2] suspension involves complex physical and chemical processes due to the presence of gas–solid–liquid phases. It is challenging to accurately predict the final …

Limestone, sedimentary rock composed mainly of calcium carbonate, usually in the form of calcite or aragonite. It may contain considerable amounts of magnesium carbonate (dolomite) as well; …

The change from barite formation to calcite formation suggest that the earliest mineralization took place at the base of the SRZ followed by mineralization within the SMTZ. Given the stratigraphic distribution of diagenetic barite‑carbonate-pyrite assemblages and variations in their occurrences in the Longmaxi Formation, we infer …

Assuming the formation of calcite will occur from a solution or an ACC phase, then by examining this interface and determining the interfacial energy we can comment on calcite nucleation. Our study allows us to examine the role of supersaturation variation at the nucleating crystal interface through a classical nucleation theory …

Formation: Regional or contact metamorphic; Acid Reaction: Being composed of calcium carbonate, marble will react in contact with many acids, neutralizing the acid. It is one of the most effective acid neutralization materials. ... Calcite and dolomite crystals and aragonite are the main components of marble.

Calcite - Mineral, Crystals, Sedimentary Rocks: A large percentage of the calcite in rocks was deposited in sedimentary environments; consequently, calcite is a constituent of several diverse sediments, sedimentary rocks, and their metamorphosed products. A minor amount of the Earth's calcite is of magmatic (i.e., igneous) origin; it is …

And this delayed, slower crystallization also allows more rod-like crystals to aggregate, which further results in the formation of calcite spherulites. 4. Conclusions. The complex and unusual morphologies of the precipitated crystals were obtained in the system of crystallisation medium with strain HJ-1. From the experimental analysis, the ...

In the intricate world of geology, the formation of calcite mineral unveils a fascinating narrative shaped by diverse geological environments. From the depths of hydrothermal …

Limestone is a sedimentary rock composed primarily of calcite, a calcium carbonate mineral with a chemical composition of CaCO 3. It usually forms in clear, calm, warm, shallow marine waters. Limestone is usually a …

Initially, the formation of amorphous calcium carbonate (ACC) begins, which then turns into calcite and vaterite phases at low temperatures (14–30 °C), while at 60–80 °C it becomes calcite and aragonite. In the third stage, the composition of vaterite and aragonite decreases along with the increase in calcite formation [9].

This bituminite staining is acquired from the bedding-parallel bituminite veins which precede calcite vein formation and represent the first liquid hydrocarbons generated. Thus, the median plane records the event of horizontal fracture initiation and represents residues of the oldest phase of hydrocarbon migration. (3)

Calcite - Mineral, Crystals, Sedimentary Rocks: A large percentage of the calcite in rocks was deposited in sedimentary environments; consequently, calcite is a constituent of several diverse …

FTIR spectra was analyzed that four prominent peaks of CaCO 3, i.e., 1796, 1436, 875, and 712 cm −1, in which the peak of 875 and 1436 cm −1 is the CO 3 out-of-plane deformation mode of the calcite. This confirms the formation of the calcite phase (Srivastava et al., 2015).

Calcite has recently attracted extensive research interest in fields ranging from geoscience to carbon dioxide removal. Although much effort has been made to study the (2x1) reconstruction of the most stable (104) surface, the origin of this reconstruction remains unclear. Here, we carefully investigate the atomic and electronic structures of …

Carbonate authigenesis at seeps results in the formation of early diagenetic carbonate phases that include aragonite, high Mg-calcite, and less commonly low Mg-calcite and dolomite (Ritger et al ...

All precipitates were dried at 25 °C before δ 18 O and Δ 47 analyses took place to remove water and provide Mg calcite for isotope analyses (verified by XRD pattern), although the precipitate may originally contain ACMC. The latter step was required to get a well-defined material (in this case calcite), where the acid fractionation factor for …

Our observations also suggest that soluble EPS can induce the formation of aragonite while bound EPS facilitate calcite erosion. Current results can provide a deeper insight into bacterially mediated mineralization of vaterite and calcium carbonate polymorphism problem, and help evaluate the significance of biogenic carbonate in the …