White Mineral Research Articles

Impact of Acidic and Alkaline Environments on the Surface Morphology of Biodentine and White Mineral Trioxide Aggregate - An In-vitro Study.

The physical and chemical properties of calcium silicate cement might be affected due to exposure to acidic or alkaline conditions during clinical use. The present study aimed to evaluate the effect of acidic and alkaline environments on the surface morphology of biodentine (BD) and white mineral trioxide aggregate (wMTA). Disc-shaped specimens of BD (n = 30) and wMTA (n = 30) were prepared in a metal mould and wrapped in pieces of gauze. They were divided into three sub-groups according to the storage media: group A, soaked in sterile distilled water at a pH of 7.0; group B, exposed to butyric acid buffered at pH 4.0; and group C, exposed to calcium hydroxide solution buffered at pH 12.0. The specimens were incubated for 7 days at 37°C, followed by examination under scanning electron microscopy at 1000x and 5000x magnification to characterise the microstructural morphology. Definite changes were seen in the microstructure of BD and wMTA on exposure to acidic and alkaline pH. The microstructure of wMTA tends to exhibit reduced cohesion when exposed to an acidic environment, especially when compared to an alkaline pH. Acidic pH exerts a milder influence on the morphological structure of BD when contrasted with its effects on wMTA. Biodentine may emerge as a more prudent choice than wMTA for utilisation in inflamed periapical regions.

Effects of using different dentin conditioners on dentin regeneration.

This experiment aimed to evaluate the impact of several dentine etching and conditioning agents on growth factors (GFs) liberation from dentine slices. Eighteen dentine slices were obtained from nine premolars divided in to six groups, the slices immersed in one mL test solutions for 5 min; Group 1: white Mineral trioxide aggregate (MTA), Group 2: Phosphate buffered saline (PBS), Group 3: 37% phosphoric acid, Group 4: 17% Ethylenediaminetetraacetic Acid (EDTA), Group 5: 10% Maleic acid (MAc), and Group 6: 0.7% Fumaric acid. The solutions were removed and stored directly at for further detection and quantification of transforming GF beta 1 (TGF-b1), bone morphogenetic protein 2 (BMP2) and vascular endothelial growth factor (VEGF) by enzyme-linked immunosorbent assay (ELISA). One-way ANOVA was used to compare the mean release and standard deviation between groups (α = 0.05). Tukey's post hoc applied for multiple comparisons. After five min conditioning of dentine slices, white MTA released the highest level of TGF-b1, BMP2 and VEGF among all groups, followed by 0.7% Fumaric acid with no significant difference between them, but compared to 37% phosphoric acid and PBS groups significant difference observed, which they released the least amount of GFs amongst all groups. Based on the results of this research the detectable release of TGF-b1, BMP2 and VEGF by 0.7% fumaric acid was comparable with white MTA from dentin slices.

Alteration Zones as Exploration Parameters for Stratiform Pb-Zn-Ag-Ba Deposits in the Graz Paleozoic (Eastern Alps, Austria)

AbstractIn the Graz Paleozoic in the Eastern Alps (Austria), stratiform Pb-Zn-Ag-Ba deposits have been mined in the past. They are classified as sedimentary-exhalative (SEDEX) deposits and are hosted by polyphase deformed greenschist facies metasediments and volcanics of the Schönberg Formation (Schöckel nappe; Drauzug-Gurktal nappe system), which is upper Silurian to Lower Devonian in age. The stratiform ore horizons are dominated by galena, sphalerite, barite, pyrite, pyrrhotite, and magnetite and are accompanied by chalcopyrite, arsenopyrite, fahlore, pyrargyrite, tetradymite, cobaltite, ullmannite, breithauptite, electrum, and others. The project MRI_SEDEXPOT investigates these deposits to evaluate their exploration potential by focusing on hydrothermal alteration zones occurring in the footwall and hanging wall of the ore. Such alteration zones are globally used as exploration tools not only for SEDEX deposits. The investigated alteration zones show distinct mineralogical and geochemical characteristics. They contain Fe rich carbonates and chlorite, K‑ and Ba-feldspars, Ba bearing white mica, fluorapatite, REE and HFSE minerals. Disseminated sulphides are widespread, and albitization is typical below sulphide rich horizons. Geochemical profiles correlate well with the observed mineralogy. Ongoing investigations of these alteration zones should lead into defining proximity indicators to the ore and evaluation of the exploration potential of the stratiform Pb-Zn-Ba-Ag deposits of the Graz Paleozoic.

Inverse Probability Weighting to Estimate Impacts of Hypothetical Occupational Limits on Radon Exposure to Reduce Lung Cancer.

Radon is a known cause of lung cancer. Protective standards for radon exposure are derived largely from studies of working populations that are prone to healthy worker survivor bias. This bias can lead to under-protection of workers and is a key barrier to understanding health effects of many exposures. We apply inverse probability weighting to study a set of hypothetical exposure limits among 4,137 male, White and American Indian radon-exposed uranium miners in the Colorado Plateau followed from 1950 to 2005. We estimate cumulative risk of lung cancer through age 90 under hypothetical occupational limits. We estimate that earlier implementation of the current US Mining Safety and Health Administration annual standard of 4 working level months (implemented here as a monthly exposure limit) could have reduced lung cancer mortality from 16/100 workers to 6/100 workers (95% confidence intervals: 3/100, 8/100), in contrast with previous estimates of 10/100 workers. Our estimate is similar to that among contemporaneous occupational cohorts. Inverse probability weighting is a simple and computationally efficient way address healthy worker survivor bias in order to contrast health effects of exposure limits and estimate the number of excess health outcomes under exposure limits at work.

Exploring the Efficacy of Using Geotrichum fermentans, Rhodotorula rubra, Kluyveromyce marxiamus, Clay Minerals, and Walnut Nutshells for Mycotoxin Remediation.

The aim of this study was to evaluate the effectiveness of nine different biological compounds to reduce mycotoxins concentrations. The hypothesis of this study was that a static in vitro gastrointestinal tract model, as an initial screening tool, can be used to simulate the efficacy of Geotrichum fermentans, Rhodotorula rubra, Kluyveromyce marxiamus yeast cell walls and their polysaccharides, red and white clay minerals, and walnuts nutshells claiming to detoxify AFB1, ZEA, DON, and T-2 toxin mycotoxins. Mycotoxin concentrations were analyzed using high-performance liquid chromatography (HPLC) with fluorescent (FLD) and ultraviolet detectors (UV). The greatest effects on reducing mycotoxin concentrations were determined as follows: for AFB1, inserted G. fermentans cell wall polysaccharides and walnut nutshells; for ZEA, inserted R. rubra and G. fermentans cell walls and red clay minerals; for DON, R. rubra cell wall polysaccharides and red clay minerals; and for T-2 toxin, R. rubra cell walls, K. marxianus, and G. fermentans cell wall polysaccharides and walnut nutshells. The present study indicated that selected mycotoxin-detoxifying biological compounds can be used to decrease mycotoxin concentrations.

Bending, electroadhesion and sensing performances of single compliant electrode dielectric elastomer actuator based on SEBS gel

Dielectric elastomer actuators (DEAs) have great potential for application in soft robotics due to their ability to undergo substantial deformations, rapid response times, and high energy density when subjected to external electrical stimuli. However, the application of DEAs in the field of soft grippers is limited by their restricted direct electro-bending capability, output force, self-sensing capacity, and pre-stretching requirement. In this study, we fabricated a single compliant electrode DEA (SCE-DEA) which was made by sandwiching a compliant electrode between two layers of poly(styrene-b-ethylene-co-butylene-b-styrene) (SEBS)/white mineral oil (WO) dielectric elastomer films. The SCE-SEBS/WO was demonstrated to have the capacities of bending, sensing, and electroadhesion (EA). The SCE-SEBS/WO can be used in various soft actuator modes, such as the unipolar EA actuator, soft gripper, and soft vibrator. The grabbing mechanism of SCE-SEBS/WO-based soft grippers with opposite bipolar configuration is caused by electric field induced bending of SEC-SEBS/WO and subsequent electrostatic attraction between both SEC-SEBS/WO. The SEC-SEBS/WO based soft grippers have rapid response detachment, and ability to grasp various types of objects. Three-layer stacked SCE-SEBS/WO-60 (with 60 wt% of WO) exhibited 531 mN cm−2 of EA stress on the paper at 3.0 kV applied voltage, and the soft gripper made by four SCE-SEBS/WO-60 can successfully grab wood blocks weighing 162.4 g at 5 kV applied voltage. The sensing capacity of SCE-SEBS/WO based soft gripper was based on the bending strain dependent resistance changes of the compliant electrode. Our results provide new insights into the fabrication of DEA based soft grippers.

White Matter Mineralization in an Adolescent Girl with Vanishing White Matter Disease

White Matter Mineralization in an Adolescent Girl with Vanishing White Matter Disease

Origin and modern microbial ecology of secondary mineral deposits in Lehman Caves, Great Basin National Park, NV, USA.

Lehman Caves is an extensively decorated high desert cave that represents one of the main tourist attractions in Great Basin National Park, Nevada. Although traditionally considered a water table cave, recent studies identified abundant speleogenetic features consistent with a hypogenic and, potentially, sulfuric acid origin. Here, we characterized white mineral deposits in the Gypsum Annex (GA) passage to determine whether these secondary deposits represent biogenic minerals formed during sulfuric acid corrosion and explored microbial communities associated with these and other mineral deposits throughout the cave. Powder X-ray diffraction (pXRD), scanning electron microscopy with electron dispersive spectroscopy (SEM-EDS), and electron microprobe analyses (EPMA) showed that, while most white mineral deposits from the GA contain gypsum, they also contain abundant calcite, silica, and other phases. Gypsum and carbonate-associated sulfate isotopic values of these deposits are variable, with δ34SV-CDT between +9.7‰ and +26.1‰, and do not reflect depleted values typically associated with replacement gypsum formed during sulfuric acid speleogenesis. Petrographic observations show that the sulfates likely co-precipitated with carbonate and SiO2 phases. Taken together, these data suggest that the deposits resulted from later-stage meteoric events and not during an initial episode of sulfuric acid speleogenesis. Most sedimentary and mineral deposits in Lehman Caves have very low microbial biomass, with the exception of select areas along the main tour route that have been impacted by tourist traffic. High-throughput 16S rRNA gene amplicon sequencing showed that microbial communities in GA sediments are distinct from those in other parts of the cave. The microbial communities that inhabit these oligotrophic secondary mineral deposits include OTUs related to known ammonia-oxidizing Nitrosococcales and Thaumarchaeota, as well as common soil taxa such as Acidobacteriota and Proteobacteria. This study reveals microbial and mineralogical diversity in a previously understudied cave and expands our understanding of the geomicrobiology of desert hypogene cave systems.

Pulp regeneration treatment using different bioactive materials in permanent teeth of pediatric subjects

Background and Objectives: The present systematic review aims to assess the success rate of the pulp regeneration treatment, according to the American Association of Endodontists (AAE) criteria, using different bioactive materials in permanent teeth of pediatric subjects (6–17 years of age). Materials and Methods: The study protocol was registered on PROSPERO and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. The question formulation was accomplished using the PICO model, and an electronic search was carried out on Scopus, MEDLINE/PubMed, Web of Science, and Cochrane databases till April 1, 2023. A total of 30 studies were established to fulfill the inclusion criteria of this systematic review. Results: A total of 273 teeth have been treated with pulp regeneration treatment. By comparing different biomaterials and the success criteria defined by the AAE, the material associated with a higher success rate was found to be the white mineral trioxide aggregate. However, the overall success rate of pulp regeneration treatment was reported for 248 out of 273 teeth (91.20%). Conclusions: Data obtained support the potential that regenerative endodontics aids in continuing root development in permanent immature teeth. Further studies are needed for a more extensive evaluation of the use of different biomaterials and the success rate in regenerative endodontics.

SOLUBILITY AND BIOMINERALIZATION ABILITY OF PMMA BONE CEMENT NANOCOMPOSITE FILLED WITH 40% NANOHYDROXYAPATITE FOR USE AS ROOT-END FILLING MATERIAL

Aim: This study was conducted to compare and evaluate the solubility and biomineralization ability of polymethyl-methacylate bone cement filled with prepared calcium phosphate based nano-fillers versus mineral trioxide aggregate when used as root end filling material. Materials and Methods: A total of forty two samples were prepared and classified into three main groups(n=14)according to the material type: Group I: white mineral trioxide aggregate, Group II: Polymethyl-methacrylate bone cement and Group III: Polymethyl-methacrylate bone cement loaded with 40% of prepared calcium phosphate based nanofillers. Each material type was mixed and packed into molds. Solubility testing was done following the ISO specification #4049 (2009). For the biomineralization ability testing, each specimen was immersed in 150 ml of simulated body fluid for 21 days. After that, the surface of the cements was analyzed by scanning electron microscope and energy dispersive X-ray analysis with computer-controlled software for elemental analysis. Results: Energy dispersive X-ray analysis results revealed the absence of both calcium and phosphorus elements in polymethyl-methacrylate bone cement samples. On the other hand, both calcium and phosphorus elements were present in the other two tested materials samples. Statistical analysis revealed a statistically significant difference between the tested groups (p<0.05). Regarding solubility, MTA (GroupI) was significantly the lowest having mean value of (0.010g/mm3), while Bone cement with nanofiller (group III) was significantly the highest having mean value (1.009 g/mm3). Conclusion: Within the limitations of the present study, it can be concluded that addition of nanohydroxyapatite to polymethyle-methacrylate bone cement enhanced its biomineralization ability to be capable of apatite formation and on the other hand, it increased its solubility.

Study on the tribological and rheological properties of magnetorheological fluids based on different base oils

Abstract Base oil has great influence on the tribological and rheological properties of magnetorheological fluid. In this paper, four types of magnetorheological fluid are prepared respectively by silicone oil, mineral oil, synthetic oil (PAO) and castor oil, and their tribological and rheological properties are investigated. Firstly, the viscosity of the magnetorheological fluid is measured by a viscometer. Then the friction coefficient and wear scar diameter of the magnetorheological fluid is measured by a four ball friction testing machine. Next, the sedimentation rate of the magnetorheological fluids is calculated by the observation method. Finally, the shear yield stress of the magnetorheological fluid is measured by a rheometer. By analyzing the experimental data, it is concluded that the magnetorheological fluid prepared by white mineral oil and castor oil has excellent wear resistance. The magnetorheological fluid prepared by castor oil has better sedimentation stability and higher shear yield stress. Consequently, the magnetorheological fluid prepared by castor oil has better comprehensive properties.

Use of Kaolin in the Pharmaceutical and Cosmetic Industries

Kaolin, a white clay mineral composed mainly of kaolinite with the chemical formula Al2O3.2SiO2.2H2O, has been a subject of interest since the days of medieval western literature. This interest increased especially after the advent of a more empirical approach to pharmacology, the establishment of pharmacopoeias, and developments in mineralogy, chemistry, as well as pharmaceutical technology. The use of kaolin in pharmaceutical (both topical and oral) and cosmetic applications has become important. Although it has long been recognized as a remedy in traditional medicine, the use of kaolin as an active ingredient for various diseases continues to be researched. Unfortunately, research focused on the use of kaolin in pharmaceuticals and cosmetics is still fairly limited. Therefore, this article aims to highlight the role and benefits of kaolin in both fields. Kaolin has been shown to have antibacterial, antiviral, and antidiarrheal properties when administered orally, as well as serve as a skin-protective agent when used topically. Aside from being an active ingredient, kaolin is also often used as an excipient in pharmaceutical formulations, acting as a filler, emulsifier, suspending agent, and crusher. In the cosmetic world, kaolin is often used as a sunscreen and to treat the skin. This article is organized based on a literature review of various articles and journals relevant to the topic discussed.

Discoloration after revascularization using calcium phosphosilicate-based bioceramic versus mineral trioxide aggregate in necrotic immature permanent anterior teeth: A Randomized clinical trial.

The aim of the current study is to evaluate the effect of calcium phophosilicate-based bioceramic "Totalfill bioceramic putty" and white mineral trioxide aggregate (WMTA) as the coronal plug on discoloration after revascularization of necrotic immature permanent anterior teeth. This study was conducted on (48) necrotic young permanent central incisors in children ranging from 8 to 14 years old, that were randomly allocated to either Totalfill bioceramic (Group I = 24) or WMTA (Group II = 24) as the coronal plug. Two visits revascularization protocol was adopted in this study using 1.5% sodium hypochlorite, followed by 17% ethylenediaminetetraacetic acid, and ending with a saline flush as irrigation solution. The double antibiotic paste was used as intracanal medication. The blood clot was used as scaffold followed by the application of collagen membrane followed by coronal plud malterial. Finally, the access was sealed using resin composite restoration and composite restoration. Clinical assessment was conducted at 1, 3, 6, 9, and 12 months, while radiographic assessment was conducted at 6 and 12 months. Data were statistically analyzed using the Chi-squared test for intergroup comparisons and Cochran's Q test for intragroup comparison. Clinically, Group I exhibited a success rate of 100%, whereas Group II exhibited a success rate of 85.7%. Radiographically, both materials showed a 90.5% success rate. There was no statistically significant difference between both materials for all assessed clinical and radiographic parameters at different follow-up periods. Both Totalfill bioceramic putty and WMTA can be used successfully as coronal plug in esthetic areas.

The influence of traditional and alternative fertilization systems on the productivity of sugar beet

Purpose. To investigate the influence of mineral, traditional and alternative organic-mineral fertilization systems on productivity and technological quality of sugar beet roots. Меthods. Long-term field and analytical. Results. Research data on the effectiveness of traditional and alternative fertilization systems in increasing the productivity and technological quality of sugar beet roots are given. The perspective of using straw, green mass of white mustard and mineral fertilizers to obtain high yield and technological quality of sugar beet roots under conditions of sufficient moisture on leached chernozem has been established. Conclusions. The mineral fertilizer system was inferior to the organic-mineral fertilization in terms of efficiency. The maximum dose of mineral fertilizers N120P80K120 ensured roots yield – 67.5 t/ha, sugar content – 17.9 %, sugar yield – 12.1 t/ha. The highest productivity of sugar beet was achieved with the application of 40 t/ha of manure + N90P60K90: yield of roots – 79.6 t/ha, sugar content – 18.2 %, sugar yield – 14.5 t/ha with an increase in yield compared to the control without fertilizers – by 37.0 t/ha, sugar yield – by 6.7 t/ha. The application of straw + green manure + N90P60K90 was determined to be promising under sugar beet: roots yield – 70.3 t/ha, sugar content – 18.2 %, sugar yield – 12.8 t/ha. The specified fertilization system was inferior to the application of 40 t/ha of manure + N90P60K90 in yield by 9.3 t/ha, sugar collection – by 1.7 t/ha. The use of fertilizers insignificantly increased the loss of sugar in molasses compared to the control without fertilizers: with the application of mineral fertilizers - by 0.01–0.05 %, 40 t/ha of manure + N90P60K90 – by 0.07 %, straw + green manure + N90P60K90 – by 0.04 %.

Investigation of Single-Phase Immersion Cooling for Modern Data Centers

Compact servers with a high energy density are the result of the telecommunications industry's rapid advancement. Innovative cooling solutions are required due to the expanding scale of data centers and related cooling needs. Servers in the data center might be cooled via immersion cooling by immersing them in a thermally conductive die electric fluid. In this study, three distinct dielectric liquids were used with variable circulation rates to examine the effectiveness of single-phase immersion cooling with varying heat inputs of 300, 400 and 500 Watts. Deionized water, white mineral oil and propylene glycol were the three dielectric fluids being considered, at circulating rates of 1, 2 and 3 litres per minute. Among the three fluids tested, deionized water consistently outperformed the others by maintaining the lowest outlet temperature across various heat inputs and flow rates. The average heat transfer coefficient for deionized water was calculated as the highest, with a value of 349.29 W/m²·K. Propylene glycol had an intermediate heat transfer coefficient, which was 194.69 W/m²·K, and mineral oil exhibited the lowest heat transfer coefficient at 74.44 W/m²·K.

Profitability, Respectability and Challenge: (Re)Gaining Control and Restructuring the Labour Process while Maintaining Racial Order at South African Gold Mines, 1913–1922

The history of black labour at the South African gold mines has conventionally been punctuated by three great African strikes, in 1920 (often obscured by the great white mine-worker strike of 1922), 1946 and 1987. The strikes of 1920, 1946 and 1987 (as well as the great white strikes of 1913 and 1922) have all attracted considerable scholarly attention. Yet a more limited black strike in 1913 has seldom, if ever, been recalled, despite its crucial importance for formulating racial policy at the gold mines, buried as it was in the violent defeat of white miners and their cohorts. This paper takes up the challenge of understanding management and state responses to collective (black and white) mine-worker struggles during the decade from 1913 to the early 1920s and assessing outcomes for worker participants, white and black alike.

Impact of water and oleic acid on glycerol monooleate phase transition and bi-continuous structure formation in white oil.

Production of biofuels from biological feedstocks, such as soybean oil, is an important piece of the transition to renewable energy sources. Processes have been developed to co-refine these feedstocks with traditional feedstocks, however, the high concentration of polar functional groups in biofeedstocks can cause a wide range of intermediate chemical reactions and interactions. An improved understanding of the interactions of biofeedstocks and their degradation products is needed to continue to expand the usage of biofeedstocks in fuel production. In this study, the equilibrium structures of glycerol monooleate (GMO), a common intermediate product of biofeedstock processing, in white mineral oil at a wide range of compositions, temperatures, and additional byproduct concentrations (water and/or oleic acid) were characterized using small angle X-ray scattering (SAXS). It was determined that GMO can exist as crystalline aggregates in white oil or as reverse micelles depending on the concentration and temperature. The critical micelle temperature increases significantly with increasing GMO concentration but remains relatively stable with increasing water or fatty acid concentration. Fitting of the SAXS data revealed that for many compositions, the GMO formed roughly spherical reverse micelles, however, at high water concentrations (∼1 wt%), the GMO formed elongated reverse micelles. Additionally, when >1 wt% oleic acid was added to the system, bi-continuous structures were stabilized rather than discreet reverse micelles. These results help increase our understanding of the structural behavior of biofeedstock intermediate products at concentrations and temperatures relevant to biofuel production and can enable processers to design systems and products that can either leverage or prevent these interactions for improved processing performance.

Physicochemical properties and antibiofilm activity of mineral trioxide aggregate associated with farnesol.

This study assessed the physicochemical and antibiofilm properties of white mineral trioxide aggregate (MTA) associated with 1 or 2% of farnesol. Setting time was evaluated based on ISO 6876/2012. Radiopacity was evaluated by radiographic analysis. pH was assessed after time intervals of 1, 3, 7, 14, 21, and 28 days. Solubility (% mass loss) and volumetric change (by micro-CT) of the cements were evaluated after immersion in distilled water. The presence of voids inside the materials was assessed by using micro-CT. Antibiofilm activity against Enterococcus faecalis was evaluated by crystal violet assay and the modified direct contact test performed with biofilm previously formed on bovine root dentin for 14 days. Data were submitted to ANOVA/Tukey tests with 5% significance level. The incorporation of farnesol into MTA increased its setting time, but decreased its solubility at 30 days and its volumetric loss in all periods (p < 0.05). Radiopacity and solubility after 7 days were similar among the materials (p > 0.05). The association of farnesol showed the highest pH value after 1 and 3 days (p < 0.05). The association of farnesol with MTA promoted a decrease in the presence of voids, and increased the antimicrobial activity on biofilm biomass of E. faecalis (p < 0.05). In conclusion, the addition of farnesol can be suggested to improve the antimicrobial properties and the consistency of MTA.

Chemical and physical properties of radiopaque Portland cement formulation with reduced particle size.

This study compared the chemical and physical properties of an experimental radiopaque white Portland cement (REPC) with reduced particle size to ProRoot white mineral trioxide aggregate (WMTA). The particle size distribution of experimental Portland cement (EPC) was examined, and then nano-zirconium oxide (nano-ZrO) was added to produce REPC. Chemical analysis, initial setting time, pH values, and push-out bond strength were evaluated. Results showed that REPC had smallest particle size (354.5±26.45 nm), while PC had the largest (1,309.67±60.54 nm) (p<0.05). Differences in chemical composition were observed. REPC exhibited shorter setting time (32.7±0.58 min) compared to WMTA (131.67±2.89 min) and PC (163.33±2.89 min) (p<0.05). All groups showed alkaline pH (p<0.05). REPC demonstrated the highest push-out bond strength (22.24±4.33 MPa) compared with WMTA (15.53±3.26 MPa) and PC (16.8±5.43 MPa) (p<0.05). This cost-effective PC formulation reduced the setting time and increased the push-out bond strength while maintaining the alkaline properties of the original cements.

Short-wavelength infrared characteristics and composition of white mica in the Demingding porphyry Cu-Mo deposit, Gangdese belt, Tibet: Implications for mineral exploration

The Demingding Cu–Mo deposit, found in the eastern Gangdese metallogenic belt in China, has a significant exploration potential. Detailed field studies coupled with short-wavelength infrared (SWIR) spectroscopy and electron probe micro analyses (EPMA) identified a total of 15 alteration minerals such as white mica group minerals, chlorite, kandite, and smectite groups. The study also discovered the spatial distribution of alteration zone patterns, including phyllic, propylitic, and intermediate argillic alterations. Furthermore, variations were observed in the Al-OH absorption position (Pos2200) of the white mica group with variable Al-Si-Fe-Mg content. Most of the white micas in the ore zone were muscovitic series, whereas the barren zone contained phengitic series micas. Some micas have undergone a transition to illite due to low-temperature alteration overprinting. The western part of the deposit exhibited lower Pos2200, higher SWIR-IC, and higher Dep2200 values, implying an intense phyllic alteration and higher paleotemperatures. These characteristics suggest that the area is in close proximity to the hydrothermal center and fluid channel. Therefore, it was identified as an exploratory target for buried copper ore bodies. The SWIR spectra of the white mica group can be used for exploration in other similar porphyry deposits. Under acidic conditions, shorter Pos2200 and higher SWIR-IC can be used as indicators for hydrothermal or mineralization centers.