Anhydrite and gypsum | SpringerLink
A possible mechanism for the formation of marine anhydrite is reaction of early-precipitated gypsum with deeper-bottom brine pools of abnormal composition, as in the Red Sea, or by reaction of sedimentary pore waters with gypsum. This could produce anhydrite formed by diagenetic changes immediately after precipitation as gypsum in the marine ...
Imaging gypsum–anhydrite interface by a structure‐based …
Therefore, delineating the interface between sedimentary cover and gypsum, and differentiating gypsum from anhydrite has significant importance in the production planning of open pits. An electrical resistivity tomography study was carried out in the Bala gypsum formation (Central Anatolia, Turkey) to map the gypsum–anhydrite …
Anhydrite
The anhydrite at a higher degree of hydration changes to gypsum forming larger crystals of newly created gypsum fitting within the relics of anhydrite, or centripetal push of anhydrite crystals. The newly formed gypsum occurs as homogeneous and fibrous at complete hydration of anhydrite that contains the remains of a rare anhydrite.
Mechanism and kinetics of gypsum–anhydrite
The transformation of gypsum into anhydrite at low temperatures under atmospheric pressure as well as at elevated temperatures (150 °C and 200 °C) inside an autoclave was investigated by monitoring changes in both the liquid and solid phases.The effect of temperature, sulfuric acid addition, anhydrite seeding and addition of sulfate …
Gypsum | Definition, Uses, & Facts | Britannica
Gypsum, common sulfate mineral of great commercial importance, composed of hydrated calcium sulfate. It occurs in extensive beds associated with other evaporite minerals, particularly in Permian and Triassic sedimentary formations; it is deposited from ocean brine, followed by anhydrite and halite.
Imaging gypsum–anhydrite interface by a structure‐based …
Abstract Principal calcium sulphate rocks, such as gypsum and anhydrite, originate from evaporitic processes. Gypsum is considered an industrial raw material with high economic value, but anhydrite has no economic interest. Therefore, delineating the interface between sedimentary cover and gypsum, and differentiating gypsum from …
KGS--Geological Log Analysis--Evaporites
Halite, anhydrite, and gypsum occur widely and a thick halite bed is developed in far west Kansas as shown on this cross-section. This log was recorded of part of the Nippewalla Group Blaine Formation evaporites in a well located in Hamilton County, Kansas.
Study on the geological and engineering aspects of anhydrite/gypsum …
Evaporitic geology, hot and arid climate, fluctuating relative humidity, and an alkaline environment governed the evolution of sedimentary deposits in the Arabian Gulf coast. Calcium sulphate generally occurs as anhydrite in the unsaturated surface layer of local soil formations. Anhydrite hydrates to gypsum with an associated volume …
Quantitative determination of anhydrite III from dehydrated gypsum …
Gypsum is formed from a saturated calcium sulfate solution [13]. Due to the different crystal structure of anhydrite III the anhydrite II will not be rehydrated by forming bassanite in solutions, but directly dissolve and precipitate as gypsum instead.
Dehydration of gypsum waste to recyclable anhydrite using …
A promising strategy for treatment and recycling of GW is to convert GW into higher-valued anhydrite, but the traditional energy-intensive calcination method …
Delineation of gypsum/anhydrite transition zone using …
Delineation of gypsum/anhydrite transition zone using electrical tomography. A case study in an active open pit, Altsi, Crete, Greece
Delineation of gypsum/anhydrite transition zone using …
In this paper, the 2D resistivity method, in combination with detailed geological mapping, is tested as tool for the mapping of gypsum/anhydrite transition …
Difference Between Gypsum and Anhydrite
Difference Between Gypsum and Anhydrite Gypsum vs Anhydrite Gypsum, also called hydrated calcium sulphate (CaSO4 · 2H2O) and anhydrite (CaSO4), also called hydrous calcium sulphate are the major minerals in the sedimentary rocks of rock gypsum and rock anhydrite respectively. Gypsum consists of calcium, …
Delineation of gypsum/anhydrite transition zone using …
Delineation of gypsum/anhydrite transition zone using electrical tomography. A case study in an active open pit, Altsi, Crete, Greece Emmanouil Manoutsoglou*, George Vachlas, George Panagopoulos and Hamdan Hamdan 1 Department of Mineral Resources Engineering, Technical University of Crete, 73100 Chania, Greece
Experimental determination and modeling of gypsum and …
A Pitzer model was used to simulate the solubility of gypsum and insoluble anhydrite in the system CaSO 4 –H 2 SO 4 –H 2 O, and their stable regions as a …
Lithology and rock type determination
Single layers of salt (NaCl), anhydrite, gypsum, coal, or tuft are easily identified when several feet thick or thicker; however, salt-plugged sandstone can mimic gas-filled clean sandstone, or a very shaly rock type can hide the presence of gas.
Dehydration Pathways of Gypsum and the Rehydration …
In this work, the dehydration pathways of gypsum and the rehydration mechanism of soluble anhydrite were mainly investigated by thermodynamic modeling and MC simulations. The dehydration pathways of gypsum are largely determined by …
Delineation of gypsum/anhydrite transition zone using …
A well known problem in the grinding procedure, in active gypsum open pits, is the difference of mechanical properties between gypsum and anhydrite. Specifically, the lower stiffness of gypsum compared to that of anhydrite, causes different energy requirements in cement production line. For these reasons it is necessary to be aware of …
Evidence of a new phase in gypsum–anhydrite …
A gypsum–anhydrite system has been analyzed by dielectric measurements under microwave heating (MW-DETA), simultaneously to Raman …
Insights Into the Micromechanics of Dehydration‐Induced …
Key Points. In situ microindentation tests reveal dehydration controlled mechanical weakening of gypsum crystals. Delamination and tensile cracking causes …
Characterization and Delineation of Gypsum Karst
The major evaporite unit within the Delaware Basin is the Castile Formation, which consists of gypsum/anhydrite and is highly susceptible to dissolution and karstification. Manifestations of karst within the Castile outcrop are abundant and include sinkholes, subsidence features and caves, both epigene and hypogene in origin.
Delineation of gypsum/anhydrite transition zone using …
More specifically, the dehydration of the primary gypsum to anhydrite occurred after burial, which resulted in the generation of a massive anhydrite volume. During the following …
Dehydration of gypsum waste to recyclable anhydrite using …
A promising strategy for treatment and recycling of GW is to convert GW into higher-valued anhydrite, but the traditional energy-intensive calcination method significantly increases the cost of recovery. Here, we report the first solid-like dehydration of gypsum to produce anhydrite at room temperature.
Gypsum | Common Minerals
Anhydrite: When gypsum loses its water component, it forms the mineral anhydrite (CaSO4). When anhydrite absorbs water it becomes gypsum. This ease of exchange is the basis of gypsum's use in plaster. Consequently, the two minerals are very similar to one another and are only easily distinguished by heating a sample in a closed tube.
The gypsum–anhydrite paradox revisited
Expected induction times of gypsum and anhydrite precipitating from an evaporating (sea)water pond. The solute concentration of Ca 2 + and SO 4 2 − steadily increases due to evaporation and the solution of a pond will become supersaturated with respect to anhydrite and gypsum (blue and pink curves in the inset, two evaporation …
Understanding gypsum in 3 diagrams
The first describes the process of water leaving the structure of gypsum to form hemihydrate or anhydrite. The second depicts the temperature-dependent solubility of the calcium sulphates in water. The third illustrates the hydration energy of hemihydrate as it reacts with water.
Anhydritec
What is anhydrite. Anhydrite is a mineral of the Calcium Sulphate family (CaSO 4).Unlike other minerals, such as gypsum (CaSO 4,2H 2 O), anhydrite does not contain any water in its crystal structure: it's an anhydrous compound. This feature, as well as its specific crystalline configuration, make anhydrite a unique material with outstanding properties …
Mechanism and kinetics of gypsum–anhydrite
Below 100 °C, the mechanism consists of a direct dehydration step of gypsum to anhydrite (with no intermediate hemihydrate formation), resulting in the …
Imaging gypsum‐anhydrite interface by a structure
Request PDF | Imaging gypsum‐anhydrite interface by a structure‐based conceptual resistivity model: A case study from Bala (Turkey) gypsum deposits | Principal calcium sulphate rocks such as ...
Origin and diagenesis of gypsum and anhydrite
This primary gypsum is replaced, with burial, by anhydrite at a temperature of 42 degrees C and theoretical depth of 2,000 feet. Anhydrite (metagypsum) occurs as beds and pore-fillings. Uplift and removal of overburden cause anhydrite to be replaced by gypsum. Variations in texture distinguish bedded, void-filling, and replacement anhydrite.