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45 pages, 1518 KB  
Review
Hydrogen Sulfide in Balneology: Physiology, Evidence, and Clinical Translation
by Jose Manuel Carbajo, Francisco Maraver, Lorena Vela and Constantin Munteanu
Int. J. Mol. Sci. 2025, 26(21), 10790; https://doi.org/10.3390/ijms262110790 - 6 Nov 2025
Viewed by 641
Abstract
This review integrates the biology and clinical translation of hydrogen sulfide (H2S) in balneology. It frames H2S as a gasotransmitters with dual chemical and biological actions and summarizes the H2S/HS equilibrium as a function of pH, [...] Read more.
This review integrates the biology and clinical translation of hydrogen sulfide (H2S) in balneology. It frames H2S as a gasotransmitters with dual chemical and biological actions and summarizes the H2S/HS equilibrium as a function of pH, temperature, and oxygenation, which governs bioaccessibility in sulfurous waters. Endogenous and exogenous sources, transport, and mitochondrial catabolism are outlined, together with core cellular mechanisms: protein persulfidation; activation of Nrf2/ARE; modulation of NF-κB; regulation of ion channels; and engagement of PI3K/Akt, MAPK/ERK, and Wnt pathways, plus epigenetic interactions with HDACs and sirtuins. Preclinical and clinical evidence in dermatology, musculoskeletal disease, and respiratory care is synthesized, alongside metabolic, cardiovascular, gastrointestinal, and renal effects. Technical aspects that preserve the bioactive fraction of H2S while meeting environmental safety limits are highlighted. Routes of administration (bathing, peloids, inhalation, and drinking cures) and key operational parameters are described. Overall, the review links physicochemical and molecular foundations with clinical indications for sulfurous waters and derivatives and identifies opportunities for research and development in H2S donors and thermal cosmetics without extrapolating beyond the available data. Full article
(This article belongs to the Section Biochemistry)
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18 pages, 2792 KB  
Article
Anti-Inflammatory Pathways Modulated by Microbial Polysaccharides from Euganean Thermal Muds in Zebrafish
by Micol Caichiolo, Raffaella Margherita Zampieri, Francesca Terrin, Annachiara Tesoriere, Fabrizio Caldara, Nicoletta La Rocca, Paolo Martini and Luisa Dalla Valle
Antioxidants 2025, 14(7), 878; https://doi.org/10.3390/antiox14070878 - 17 Jul 2025
Viewed by 1000
Abstract
Thermal mud produced by spas of the Euganean Thermal District (Italy) has been used since ancient times for therapeutic purposes. Recently, the anti-inflammatory activity of microbial polysaccharides (M-PS), extracted from traditionally maturated muds, was demonstrated using the zebrafish model organism. However, the downstream [...] Read more.
Thermal mud produced by spas of the Euganean Thermal District (Italy) has been used since ancient times for therapeutic purposes. Recently, the anti-inflammatory activity of microbial polysaccharides (M-PS), extracted from traditionally maturated muds, was demonstrated using the zebrafish model organism. However, the downstream signalling pathways regulated by M-PS remain largely unknown. In this study, to investigate the underlying mechanisms of inflammation resolution, we performed a transcriptome analysis on zebrafish larvae inflamed with copper sulphate and treated with M-PS. Our findings revealed that M-PS treatment down-regulated the expression of key genes involved in several inflammatory pathways. Gene Set Enrichment Analysis identified eleven up-regulated pathways (e.g., TNF-α signalling via NFκB, IL6–JAK–STAT signalling, p53 pathway, apoptosis, and interferon response) with components reduced in number and expression level in M-PS-treated larvae compared to the inflamed ones. Additionally, seven down-regulated pathways were identified (e.g., transcription factors E2F, MYC, and the G2M checkpoint). DEG-pseudotime analysis further confirmed the association of these genes with the pathways identified by GSEA. These results provide valuable insights into the anti-inflammatory properties of M-PS and the therapeutic potential of Euganean thermal muds for inflammatory diseases. Full article
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19 pages, 2933 KB  
Article
Hepatoprotective Activity of Nature-Derived Polyphenols Studied by Mass Spectrometry Based Multi-OMICS Approach
by Alexander G. Brzhozovskiy, Savva D. Semenov, Alexander Y. Zherebker, Anna E. Bugrova, Maria N. Yurova, Yury V. Zhernov, Oxana A. Kovaleva, Alexander L. Semenov, Dmitry P. Abroskin, Stepan S. Kruglov, Elena I. Fedoros, Alexey S. Kononikhin and Evgeniy N. Nikolaev
Int. J. Mol. Sci. 2025, 26(4), 1604; https://doi.org/10.3390/ijms26041604 - 13 Feb 2025
Viewed by 1742
Abstract
The aim of this study was to examine the hepatoprotective activity of multicomponent mixtures of natural origin in the BALB/C mouse model, with subacute liver failure (SALF) induced by the administration of toxin carbon tetrachloride (CCl4). The hepatoprotective activity of activated [...] Read more.
The aim of this study was to examine the hepatoprotective activity of multicomponent mixtures of natural origin in the BALB/C mouse model, with subacute liver failure (SALF) induced by the administration of toxin carbon tetrachloride (CCl4). The hepatoprotective activity of activated hydrolytic lignin (BP-Cx-1), humic acid peloids (HA), and isoflavones from kudzu Pueraria lobata roots (IFL) was evaluated using mass spectrometry (MS)-based omics technologies. Our MS-based approach revealed new insights into the molecular mechanisms of the hepatoprotective activity of multicomponent mixtures of natural origin. Significant differences were observed in the proteome and metabolome profiles of the urine and liver of BALB/c mice with SALF between a control group with CCl4 administration, intact controls, and groups receiving potential hepatoprotectors of natural origin (BP-Cx-1, HA, IFL). Proteomic and metabolomics analyses demonstrated that among the hepatoprotectors, IFL possessed the highest hepatoprotective potential, which correlated well with the relative effectiveness of the drugs recorded during in vitro studies. These results correlate with the relative effectiveness of the drugs recorded in previous in vitro and in vivo studies. The leading IFL activity may be attributed to a higher content of active polyphenolic components compared to heterogeneous HA and BP-Cx-1. Enrichment with active components by fractionation is a direction that can be explored for developing hepatoprotective agents based on natural complex polyphenols. Full article
(This article belongs to the Special Issue Role of Proteomics in Human Diseases and Infections)
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26 pages, 2250 KB  
Article
Balneotherapy as a Complementary Intervention for Stress and Cortisol Reduction: Findings from a Randomized Controlled Trial
by Lolita Rapolienė, Dovydas Rapolis, Aelita Bredelytė, Giedrė Taletavičienė, Antonella Fioravanti and Arvydas Martinkėnas
Brain Sci. 2025, 15(2), 165; https://doi.org/10.3390/brainsci15020165 - 7 Feb 2025
Cited by 5 | Viewed by 5588
Abstract
Background: In our modern era, stress has become a pervasive challenge, affecting individuals across all ages and backgrounds. Acute or chronic stress and elevated cortisol levels are known to impair neurological function and hinder rehabilitation outcomes. Therefore, effective treatment methods that reduce stress, [...] Read more.
Background: In our modern era, stress has become a pervasive challenge, affecting individuals across all ages and backgrounds. Acute or chronic stress and elevated cortisol levels are known to impair neurological function and hinder rehabilitation outcomes. Therefore, effective treatment methods that reduce stress, enhance mental health, and promote overall well-being are urgently needed. The aim of this study was to evaluate the seasonal impact of balneotherapy on distress, as measured by the General Symptoms Distress Scale (GSDS), and well-being, as assessed using the Arizona Integrative Outcomes Scale (AIOS), and the effect of winter balneotherapy on salivary cortisol levels. Methods: In 2023, a multicenter, single-blind, parallel-group, randomized controlled trial was carried out across six medical spa centers in Lithuania. Participants with a stress intensity greater than 3 points on the Visual Analogue Scale (VAS) underwent combined natural resource-based therapies over a 1- to 2-week treatment period. Outcomes were assessed using the General Symptom Distress and Arizona Integrative Outcomes scales, along with salivary cortisol measurements after winter intervention. Results: The results demonstrated a significant reduction in distress intensity by 1–3.5 points (VAS), with winter interventions showing greater efficacy compared to summer. Participants also experienced an increase in well-being by up to 3 points (VAS), improved stress management by up to 1.9 points (VAS), and a reduction in salivary cortisol levels by 0.9 units following winter-based treatments. Some gender differences emerged in specific groups. Conclusions: Our study provides robust evidence for the stress-reducing effects of balneotherapy, particularly highlighting the enhanced efficacy of winter interventions. These findings are especially relevant for neurological rehabilitation, where stress reduction and improved autonomic regulation can support neuroplasticity, recovery processes, and overall quality of life. This research offers valuable insights for developing holistic, seasonally optimized strategies to aid stress management and promote neurological health. Full article
(This article belongs to the Special Issue The Rehabilitation of Neurologic Disorders)
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14 pages, 1891 KB  
Article
Balneotherapy (Mud-Bath Therapy) with a Peloid Enriched with Rosmarinic Acid Enhances Clinical Outcomes and Innate Immune Benefits in Elderly Patients with Osteoarthritis: A Pilot Study
by Eduardo Ortega-Collazos, María Dolores Hinchado, Eduardo Otero, Casimiro Fermín López-Jurado, Isabel Gálvez, José Luis Legido, Juan Francisco Sánchez Muñoz-Torrero, Eduardo Ortega and Silvia Torres-Piles
Appl. Sci. 2024, 14(24), 12017; https://doi.org/10.3390/app142412017 - 22 Dec 2024
Cited by 4 | Viewed by 3886
Abstract
Osteoarthritis (OA) is a common chronic condition that causes pain and disability, particularly in the elderly, resulting in significant limitations on mobility and overall quality of life. Balneotherapy using peloids (mud therapy) is an effective, non-pharmacological treatment for OA that improves symptoms and [...] Read more.
Osteoarthritis (OA) is a common chronic condition that causes pain and disability, particularly in the elderly, resulting in significant limitations on mobility and overall quality of life. Balneotherapy using peloids (mud therapy) is an effective, non-pharmacological treatment for OA that improves symptoms and function. This pilot study aimed to assess whether a controlled-matured peloid, supplemented with rosmarinic acid (RosA), could enhance clinical outcomes, functional status, and immune response in OA patients. The study involved 42 elderly OA patients (mean age 70), comparing a 10-day balneotherapy cycle using either a RosA-fortified or non-fortified peloid. The effects on pain (Visual Analogue Scale), functional status (WOMAC, knee flexion/extension), quality of life (EUROQOL), and innate immune response (neutrophil phagocytic and microbicidal activity) were evaluated. Both treatments resulted in significant improvements in pain (by approximately 60%), function, and quality of life, but the RosA-fortified peloid led to greater benefits, particularly in the anxiety/depression dimension of the EUROQOL questionnaire and in enhancing neutrophil immune responsiveness. These findings suggest that RosA supplementation may further improve the therapeutic effects of mud therapy for OA management. Full article
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31 pages, 16883 KB  
Article
Lithostratigraphy and Limestone Microfacies of the Jafnayn Formation (Paleocene to Early Eocene, Al-Khod, Sultanate of Oman): Deposition in a Restricted Lagoon with Intervals of Open Marine Conditions
by Frank Mattern, Andreas Scharf, Abdul Razak Al-Sayigh, Abdulaziz Al-Mamari, Laura Galluccio, Sundus Al-Ghaiti, Gianluca Frijia, Lorenzo Consorti, Maram Al-Saadi and Fatema Al-Jabri
Geosciences 2024, 14(12), 352; https://doi.org/10.3390/geosciences14120352 - 18 Dec 2024
Cited by 1 | Viewed by 1704
Abstract
We studied the Jafnayn Formation’s lithostratigraphy, microfacies, depositional environment, and uncertain presence of the Paleocene/Eocene boundary and present the first detailed analysis of a 127-m-thick section using the standard microfacies (SMF)/facies zone (FZ) system. The formation is dominated by foraminiferal grainstones and packstones [...] Read more.
We studied the Jafnayn Formation’s lithostratigraphy, microfacies, depositional environment, and uncertain presence of the Paleocene/Eocene boundary and present the first detailed analysis of a 127-m-thick section using the standard microfacies (SMF)/facies zone (FZ) system. The formation is dominated by foraminiferal grainstones and packstones of SMF 18-FOR, followed by peloidal grainstones and packstones of SMF 16. Coral-red algae floatstones of SMF 8 occur sporadically. SMF 18-DASY appears only once. SMF 16 and 18-FOR suggest a restricted lagoon, whereas SMF 8 and 18-DASY reflect episodic open marine lagoonal conditions. The section consists of four lithostratigraphic units. Considerable detrital quartz near the base (Unit 1: 22%; sand, sandstone, conglomerate) and top (Unit 4: 40%; sand) coincides with a restricted lagoon affected by near-shore processes (base) and near-shore conditions (top). Open marine conditions show an elevated bioclast diversity in units 3 and 4. Unit 2 displays very thickly-bedded limestones of the restricted lagoon. The lagoon barriers likely consist of foraminifera and other allochems that were reworked from the lagoon to form shoals. Coral remains in units 3 and 4 suggest that coral build-ups in the upper part of the formation protected the lagoon as well. The early Eocene age of several basal Alveolina species in the lowermost 9 m of the studied section indicates that the section is incomplete, with the late Paleocene part and meters-thick basal yellow marl missing. The Paleocene/Eocene boundary is unexposed. Full article
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21 pages, 2216 KB  
Review
Peloids in Skin Care and Cosmeceuticals
by M. Lourdes Mourelle, Carmen P. Gómez and José L. Legido
Cosmetics 2024, 11(6), 202; https://doi.org/10.3390/cosmetics11060202 - 22 Nov 2024
Cited by 4 | Viewed by 3961
Abstract
Peloids are mixtures of clays, sediments, or peat with mineral–medicinal water or seawater, or salt-lake water used in spa therapy for different treatments, including dermatological ones. The origin of peloids can be natural; that is, they are formed in situ at the place [...] Read more.
Peloids are mixtures of clays, sediments, or peat with mineral–medicinal water or seawater, or salt-lake water used in spa therapy for different treatments, including dermatological ones. The origin of peloids can be natural; that is, they are formed in situ at the place where the thermal water emerges or on the shores of the sea or salt lake, or they are prepared ad hoc from high-quality materials, such as clays or peat. Peloids are also used as cosmeceuticals in skin care to treat different skin disorders and/or conditions, such as psoriasis, eczema, and other scaly disorders, sensitive skin, and acne. This review reports all available scientific data concerning the effects and specific activities of peloids in skin care and cosmeceuticals, providing a better understanding of the clinical and cosmetic benefits. Finally, the safety and regulation of peloids are also discussed. Full article
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28 pages, 34681 KB  
Article
Dancing Towards the End—Ecological Oscillations in Mediterranean Coral Reefs Prior to the Messinian Salinity Crisis (Calcare di Rosignano Formation, Acquabona, Tuscany, Italy)
by Giovanni Coletti, Alberto Vimercati, Francesca R. Bosellini, Alberto Collareta, Giulia Bosio, Adriano Guido, Alessandro Vescogni, Daniela Basso and Or M. Bialik
Geosciences 2024, 14(11), 285; https://doi.org/10.3390/geosciences14110285 - 25 Oct 2024
Viewed by 3286
Abstract
The lower Messinian Calcare di Rosignano Formation (Tuscany, Italy, 43° N) preserves one of the youngest and northernmost examples of coral reefs in the Mediterranean. The outcropping succession of the Acquabona quarry consists of four main facies, namely, in ascending stratigraphic order: (1) [...] Read more.
The lower Messinian Calcare di Rosignano Formation (Tuscany, Italy, 43° N) preserves one of the youngest and northernmost examples of coral reefs in the Mediterranean. The outcropping succession of the Acquabona quarry consists of four main facies, namely, in ascending stratigraphic order: (1) coral boundstone, (2) coralline algal rudstone, (3) serpulid floatstone to packstone, and (4) peloidal packstone to grainstone. The succession displays a trend toward increasingly more shallow conditions and progressively more restricted water circulation. The coral reef displays a limited coral biodiversity and a remarkable abundance of heterotrophs, similar to modern coral reefs developed at the edges of the ecological niche of symbiont-bearing colonial corals. The widespread presence of coral colonies pervasively encrusted by coralline algae and benthic foraminifera suggests that short-term environmental perturbations caused temporary shutdowns of the coral-dominated carbonate factory. Moving upwards, there are fewer corals and more highly adaptable carbonate producers like coralline algae and serpulids. This suggests that the decline of corals had been caused by the conditions in the basin becoming more stressful, up to the collapse of the coral community. The overall succession indicates that coral-dominated ecosystems located at the edges of the coral zone are very sensitive; they can be affected even by minor perturbations and easily collapse if negative conditions persist. Full article
(This article belongs to the Special Issue Advances in Carbonate Diagenesis)
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24 pages, 1559 KB  
Review
Potential Possibilities of Using Peat, Humic Substances, and Sulfurous Waters in Cosmetology
by Ewelina Maria Błońska-Sikora, Marta Klimek-Szczykutowicz, Monika Michalak, Katarzyna Kulik-Siarek and Małgorzata Wrzosek
Appl. Sci. 2024, 14(16), 6912; https://doi.org/10.3390/app14166912 - 7 Aug 2024
Cited by 4 | Viewed by 4412
Abstract
Balneology is one of the oldest fields of medicine related to the use of natural raw materials (medicinal waters, medicinal gases, peloids, climatic values) in the treatment, prevention, and rehabilitation of many diseases but also increasingly in cosmetology. Currently, balneotherapy (spa therapy) combines [...] Read more.
Balneology is one of the oldest fields of medicine related to the use of natural raw materials (medicinal waters, medicinal gases, peloids, climatic values) in the treatment, prevention, and rehabilitation of many diseases but also increasingly in cosmetology. Currently, balneotherapy (spa therapy) combines tradition and modernity. The interest in spa treatments, the popularity of a healthy lifestyle, as well as the constant search for active substances of a natural origin for cosmetics make peloids, medicinal, and mineral waters very popular in the cosmetics industry. The main aim of this review was to present current, scientifically proven knowledge about the potential use of peat, huic substances, and sulfurous water in cosmetology. The work describes the potential possibilities of using medicinal waters, especially sulfurous waters, as well as peats and humic compounds, which are the source of active substances with biological activity e.g., antibacterial, anti-inflammatory, and antioxidant, and possess a positive effect on psoriasis, atopic dermatitis, or acne. The therapeutic effects of these substances have been well documented in the literature; however, the validity of their use in cosmetology requires further confirmation. Full article
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23 pages, 20878 KB  
Article
Heterogeneous Reservoir Petrophysical Property and Controlling Factors in Semi-Restricted Depositional Setting: A Case Study of Yamama Formation, X Oilfield, Middle East
by Fengfeng Li, Lei Li, Haowei Chen, Wenyu Wang and Yang Wan
J. Mar. Sci. Eng. 2024, 12(6), 1011; https://doi.org/10.3390/jmse12061011 - 18 Jun 2024
Viewed by 2518
Abstract
The Early Cretaceous Yamama Formation of X oilfield, deposited in a semi-restricted setting, holds considerable oil reserves. However, the reservoir is extremely heterogeneous and is poorly studied. Integrating outcrops, cores, cast thin sections, regular or special core analysis, wireline logging data from six [...] Read more.
The Early Cretaceous Yamama Formation of X oilfield, deposited in a semi-restricted setting, holds considerable oil reserves. However, the reservoir is extremely heterogeneous and is poorly studied. Integrating outcrops, cores, cast thin sections, regular or special core analysis, wireline logging data from six wells, and seismic data, this study provides an improved understanding of reservoir petrophysical characteristics and geological controlling factors including sedimentation, diagenesis, and sequence. The results showed that eight lithologies are developed in the Yamama Formation, of which packstone and wackstone are dominant. The physical properties span a wide range, with porosity mainly distributed between 10% and 25%, and the permeability mainly distributed between 0.1 mD and 1 mD. Nine types of pores are developed, with moldic pores, micropores, and skeletal pores being the most developed. The reservoir has six types of microstructures, of which the poorly sorted with mega-throat represent the best reservoir. The Yamama Formation was mainly deposited in a lagoon, along with five other facies, such as supratidal flat, patchy reef, back shoal, shoal, and open shelf. Six types of diageneses are developed, with dissolution during the penecontemporaneous stage being the most beneficial to the reservoir and cementation being the most destructive. Three sequences were recognized in the Yamama Formation. It concluded that the hydrodynamics in semi-restricted depositional setting is weak overall and does not have the potential to develop large-scale high-quality reservoirs. A wide range of bioclasts were selectively dissolved to form a large number of secondary pores. Sediments rich in Algae, Bacinella, and peloids tend to form moldic pores, skeletal pores, and intergranular pores, respectively, which are prone to be favorable reservoirs. Controlled by the coupling of sedimentation and diagenesis driven by sequence, the reservoir is extremely heterogenous. Full article
(This article belongs to the Special Issue Exploration and Development of Marine Energy)
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19 pages, 3995 KB  
Article
Microbial Polysaccharides Extracted from Different Mature Muds of the Euganean Thermal District Show Similar Anti-Inflammatory Activity In Vivo
by Micol Caichiolo, Raffaella Margherita Zampieri, Alessandra Adessi, Matilde Ciani, Fabrizio Caldara, Luisa Dalla Valle and Nicoletta La Rocca
Int. J. Mol. Sci. 2024, 25(9), 4999; https://doi.org/10.3390/ijms25094999 - 3 May 2024
Cited by 7 | Viewed by 2057
Abstract
The Euganean Thermal District, situated in North-East Italy, is one of Europe’s largest and oldest thermal centres. The topical application of its therapeutic thermal muds is recognised by the Italian Health System as a beneficial treatment for patients suffering from arthro-rheumatic diseases. Polysaccharides [...] Read more.
The Euganean Thermal District, situated in North-East Italy, is one of Europe’s largest and oldest thermal centres. The topical application of its therapeutic thermal muds is recognised by the Italian Health System as a beneficial treatment for patients suffering from arthro-rheumatic diseases. Polysaccharides produced by the mud microbiota have been recently identified as anti-inflammatory bioactive molecules. In this paper we analysed the efficacy of Microbial-Polysaccharides (M-PS) derived from mature muds obtained at different maturation temperatures, both within and outside the codified traditional mud maturation range. M-PSs were extracted from six mature muds produced by five spas of the Euganean Thermal District and investigated for their chemical properties, monosaccharide composition and in vivo anti-inflammatory potential, using the zebrafish model organism. Additionally, mature muds were characterized for their microbiota composition using Next-Generation Sequencing. The results showed that all M-PSs exhibit similar anti-inflammatory potential, referable to their comparable chemical composition. This consistency was observed despite changes in cyanobacteria populations, suggesting a possible role of the entire microbial community in shaping the properties of these biomolecules. These findings highlight the importance of scientific research in untangling the origins of the therapeutic efficacy of Euganean Thermal muds in the treatment of chronic inflammatory conditions. Full article
(This article belongs to the Special Issue Investigation of Natural Products as Sources of Bioactive Molecules)
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18 pages, 2092 KB  
Article
Microbial Composition Dynamics in Peloids Used for Spa Procedures in Lithuania: Pilot Study
by Marija Kataržytė, Lolita Rapolienė, Greta Kalvaitienė and Rafael Picazo-Espinosa
Int. J. Environ. Res. Public Health 2024, 21(3), 335; https://doi.org/10.3390/ijerph21030335 - 12 Mar 2024
Cited by 2 | Viewed by 2820
Abstract
Despite peloids’ acknowledged therapeutic and cosmetic potential, there remains a limited understanding of their microbial diversity and dynamics, especially concerning beneficial and non-beneficial microorganisms under different heating conditions. Our study employs both cultivation and metagenomic methods to assess the microbiota of peloids, focusing [...] Read more.
Despite peloids’ acknowledged therapeutic and cosmetic potential, there remains a limited understanding of their microbial diversity and dynamics, especially concerning beneficial and non-beneficial microorganisms under different heating conditions. Our study employs both cultivation and metagenomic methods to assess the microbiota of peloids, focusing on lake sapropel and peat under heating conditions recommended for external application and safety assurance. By applying microbial indicators specified in national regulatory documents, we found that all peloids reached thresholds for sulphite-reducing clostridia and colony-forming units. Each peloid exhibited a distinctive bacterial composition based on metagenomic analysis, and temperature-induced changes were observed in microbial diversity. We identified beneficial bacteria potentially contributing to the therapeutic properties of peloids. However, the same peloids indicated the presence of bacteria of human faecal origin, with a notably higher abundance of Escherichia coli, pointing to a potential source of contamination. Unfortunately, it remains unclear at which stage this contamination entered the peloids. The findings underscore the importance of monitoring and controlling microbial aspects in peloid applications, emphasising the need for measures to prevent and address contamination during their preparation and application processes. Full article
(This article belongs to the Section Environmental Sciences)
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35 pages, 37975 KB  
Article
Interactions between Clays and Carbonates in the Aptian Pre-Salt Reservoirs of Santos Basin, Eastern Brazilian Margin
by Argos Belmonte Silveira Schrank, Thisiane Dos Santos, Sabrina Danni Altenhofen, William Freitas, Elias Cembrani, Thiago Haubert, Felipe Dalla Vecchia, Rosalia Barili, Amanda Goulart Rodrigues, Anderson Maraschin and Luiz Fernando De Ros
Minerals 2024, 14(2), 191; https://doi.org/10.3390/min14020191 - 11 Feb 2024
Cited by 9 | Viewed by 4135
Abstract
The giant Pre-salt reservoirs represent most of the oil production in Brazil. The main Aptian sag reservoirs were deposited in a unique and highly complex hyper-alkaline lacustrine setting. These deposits are essentially constituted by fascicular and spherulitic calcite precipitated in a magnesian clay [...] Read more.
The giant Pre-salt reservoirs represent most of the oil production in Brazil. The main Aptian sag reservoirs were deposited in a unique and highly complex hyper-alkaline lacustrine setting. These deposits are essentially constituted by fascicular and spherulitic calcite precipitated in a magnesian clay matrix (stevensite, kerolite, and saponite/hectorite). Although vital for understanding the origin and main reservoir quality control, the genesis and interactions of clays and carbonates are still poorly constrained. The detailed petrographic description was focused on 812 thin sections from five wells drilled in the Santos Basin Aptian Barra Velha Formation, combined with cathodoluminescence, UV epifluorescence, and X-ray diffraction analyses. The main syngenetic processes were the deposition of finely laminated peloidal and ooidal Mg-clays, the formation of fascicular calcite crusts on the sediment–water interface, and the redeposition of these materials as intraclasts. Abundant clay peloids engulfed in syngenetic shrubs indicate that calcite and clay precipitation was concomitant, though with highly variable rates. Eodiagenetic phases include matrix-replacive and -displacive spherulites and fascicular shrubs; matrix-replacive blocky calcite and dolomite; lamellar carbonates filling matrix shrinkage pores; and microcrystalline calcite, dolomite, and silica replacing the Mg-clay matrix. The preferential dolomitization and calcitization of peloidal layers were most likely due to their higher permeability and larger specific surface. Matrix-replacive saddle dolomite, macrocrystalline calcite, and dawsonite are interpreted as mesodiagenetic or hydrothermal phases after significant matrix dissolution. Unraveling the processes of the formation and alteration of the carbonates and clays and their interactions in the Pre-salt deposits is essential for constraining the depositional and diagenetic conditions in their unique environments and their diagenetic overprinting and for decreasing the exploration risks and increasing the production of those extraordinary reservoirs. Full article
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27 pages, 39970 KB  
Article
The Middle Miocene Microfacies, Cyclicity, and Depositional History: Implications on the Marmarica Formation at the Siwa Oasis, Western Desert (Egypt)
by Mohamed A. Khalifa, Amr S. Zaky, Luigi Jovane, Ahmed M. El-Hewy, Esam Zahran and Atef M. Kasem
Minerals 2024, 14(1), 73; https://doi.org/10.3390/min14010073 - 8 Jan 2024
Cited by 5 | Viewed by 2918
Abstract
Microfacies studies were carried out on the Middle Miocene Marmarica Formation exposed at the Gabal Western Bahi El-Din and Gabal El-Najdeen, the Siwa Oasis, northwestern Desert (Egypt). It was distinguished into the lower, middle, and upper members. Eleven microfacies types were recognized, which [...] Read more.
Microfacies studies were carried out on the Middle Miocene Marmarica Formation exposed at the Gabal Western Bahi El-Din and Gabal El-Najdeen, the Siwa Oasis, northwestern Desert (Egypt). It was distinguished into the lower, middle, and upper members. Eleven microfacies types were recognized, which include skeletal lime-mudstone, dolomitic lime-mudstone, intraclastic wackestone, bryozoan wackestone, foraminiferal wackestone, foraminiferal bryozoan packstone, glauconitic molluscan packstone, molluscan intraclastic packstone, pelletal peloidal skeletal packstone, dolostones, and claystone microfacies. This formation includes several types of emergence- meter-scale cycles (shallowing-upward). Field observations and petrographic analyses revealed that these cycles consist of pure carbonates and mixed siliciclastic carbonates. These cycles consist of four types of gradual cycles and six types of non-gradual cycles. The gradual emergence cycles indicate a balance between the rate of subsidence, sea level oscillations, and sedimentation rate. The non-gradual cycles indicate an irregular balance between sedimentation rate and subsidence rate. The non-gradual cycles denote high-frequency sea level variation and/or short-term sea level oscillations, which are associated with high carbonate formation. The depositional environments of the Marmarica Formation are restricted to lagoonal at the base, followed upward to open marine conditions. Both environments most probably characterize the platform setting. Full article
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27 pages, 6498 KB  
Article
Unveiling the Diagenetic and Mineralogical Impact on the Carbonate Formation of the Indus Basin, Pakistan: Implications for Reservoir Characterization and Quality Assessment
by Faisal Hussain Memon, Abdul Haque Tunio, Khalil Rehman Memon, Aftab Ahmed Mahesar and Ghulam Abbas
Minerals 2023, 13(12), 1474; https://doi.org/10.3390/min13121474 - 23 Nov 2023
Cited by 7 | Viewed by 2930
Abstract
The Chiltan formation is a potential hydrocarbon-producing reservoir in the Indus Basin, Pakistan. However, its diagenetic alterations and heterogeneous behavior lead to significant challenges in accurately characterizing the reservoir and production performance. This manuscript aims to utilize six carbonate core samples of the [...] Read more.
The Chiltan formation is a potential hydrocarbon-producing reservoir in the Indus Basin, Pakistan. However, its diagenetic alterations and heterogeneous behavior lead to significant challenges in accurately characterizing the reservoir and production performance. This manuscript aims to utilize six carbonate core samples of the Chiltan limestone to conduct an in-depth analysis of the diagenetic impacts on reservoir quality. The comprehensive formation evaluation was carried out through thin-section analysis, SEM-EDS, and FTIR investigation, as well as plug porosity and permeability measurements under varying stress conditions. In result, petrography revealed three microfacies of intraclastic packestone (MF1), bioclastic pelliodal packestone (MF2), and bioclastic ooidal grainstone (MF3), with distinct diagenetic features and micro-nano fossil assemblages. The MF1 microfacies consist of bioclasts, ooids, pellets, and induced calcite, while the MF2 microfacies contain micrite cemented peloids, algae, and gastropods. Although, the MF3 grainstone microfacies contains key features of bioclasts, milliods, bivalves, echinoderms, and branchiopods with intense micritization. Diagenesis has a significant impact on petrophysical properties, leading to increased reservoir heterogeneity. The specified depositional environment exposed the alteration of the Chiltan formation during distinct diagenetic phases in marine, meteoric, and burial settings. Marine diagenesis involves biogenic carbonates and micro-nano fossils, while meteoric diagenesis involves mineral dissolution, reprecipitation, secondary porosity, compaction, cementation, and stylolite formation. Pore morphology and mineralogy reveal a complex pore network within the formation, including a micro-nano pore structure, inter–intra particle, moldic, vuggy, and fenestral pores with variations in shape, connectivity, and distribution. Various carbonate mineral phases in the formation samples were analyzed, including the calcite matrix and dolomite crystals, while silica, calcite, and clay minerals were commonly observed cement types in the analysis. The core samples analyzed showed poor reservoir quality, with porosity values ranging from 2.02% to 5.31% and permeability values from 0.264 mD to 0.732 mD, with a standard deviation of 1.21. Stress sensitivity was determined using Klinkenberg-corrected permeability at increasing pore pressure conditions, which indicated around 22%–25% reduction in the measured gas permeability and 7% in Klinkenberg permeability due to increasing the net confining stress. In conclusion, the Chiltan formation possesses intricate reservoir heterogeneity and varied micropore structures caused by diagenesis and depositional settings. The formation exhibits nonuniform pore geometry and low petrophysical properties caused by the diverse depositional environment and various minerals and cement types that result in a low-quality reservoir. Stress sensitivity further decreases the permeability with varying stress levels, emphasizing the need of stress effects in reservoir management. The results of this study provide a solid foundation in reservoir characterization and quality assessment that has implications for predicting fluid flow behavior, providing insight into geological evolution and its impact on reservoir quality and leading to improving resource exploration and production strategies. Full article
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