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Serpentine group minerals—comprising antigorite, chrysotile, and lizardite—are key indicators of the hydration of ultramafic rocks and the serpentinization process. In this study, the mineralogical, chemical, and structural characteristics of serpentinites located north of Divriği, as well as serpentinization processes, were investigated using XRD, SEM, FTIR, and ICP-MS analyses, and an attempt was made to determine OH stretching characteristics associated with the serpentinization process. While low ∑REE contents (11.07–15.13 ppm) indicate that serpentinites originated from an REE-depleted ultramafic protolith, SEM and FTIR findings—consistent with microscopic observations—reveal the presence of antigorite, chrysotile, and lizardite varieties of serpentine in varying proportions across the selected samples. Antigorite is more prominent in samples ESp-1 and ESp-2, whereas chrysotile is more distinct in ESp-3. In FTIR spectra, OH stretching bands in the 3600–3750 cm⁻¹ range and Si–O vibrations in the 400–1200 cm⁻¹ range confirm the presence of serpentine-group minerals. The multi-band structure in the OH region and strong Si–O band around ~994 cm⁻¹ indicate the coexistence of antigorite and chrysotile. The combined evaluation of FTIR, SEM, XRD, and geochemical data highlights the necessity of a multi-analytical approach to distinguish between serpentine polymorphs and demonstrates that serpentinization involves a multi-stage mineral transformation process. Consequently, the formation of serpentine minerals and serpentinization are the result of a multi-stage process controlled by protolith composition, fluid–rock interaction, and varying physicochemical conditions.

This study presents the first detailed investigation of pyroxene zoning within polymetallic skarn zones of the Elazığ region. Skarns develop along contacts between plutonic rocks (diorite and granite) and carbonate rocks, forming two main zones: endoskarn and exoskarn. Endoskarns exhibit clear mineralogical zoning, including pyroxene–garnet, pyroxene–scapolite, and epidote–garnet assemblages, while scapolite occurs in both endoskarn and exoskarn zones. Minor serpentinized olivine within endoskarns is attributed to localized magnesium enrichment due to partial assimilation of low-Mg magma by dolomitic marbles. Geochemical analyses reveal systematic variations in pyroxene composition related to ore type: Cu-Fe skarns show low Mn/Fe ratios (0.2) and elevated Zn (>200 ppm), and W-bearing skarns display intermediate Mn/Fe ratios (~0.15) with high Zn (>500 ppm). These findings highlight the value of pyroxene Mn/Fe ratios and Zn contents as indicators of hydrothermal fluid evolution and skarn-forming processes. Overall, this study provides the first evidence of oscillatory zoning in pyroxenes from polymetallic skarns in the region, demonstrating the interplay between magmatic differentiation and hydrothermal mineralization.

The accurate classification of rocks is crucial for applications such as earthquake prediction, resource exploration, and geological analysis. Traditional methods rely on expert examination of thin-section images under a microscope, making the process time-consuming and prone to errors. Recent advancements in deep learning have emerged as a powerful tool for automated rock classification; however, distinguishing between similar rock types such as sedimentary, metamorphic, and magmatic rocks remains a challenge. This study proposes a novel hybrid convolutional neural network (CNN) approach that combines the strengths of VGG16 and EfficientNetV2 architectures for the classification of thin-section rock images. The model, developed using the Feature-Selected Hybrid Network (FSHNet), demonstrates significant improvements over individual models, achieving a 5% increase in accuracy compared to Efficient-NetV2B0 and a 9% increase compared to VGG16. By employing the ReliefF algorithm for feature selection and Support Vector Machines (SVMs) for classification, the model further reduces the dimensionality of the feature space, enhancing computational efficiency. The proposed model has been applied to two different rock datasets. The first dataset consists of 2634 images, categorized into sedimentary, metamorphic, and magmatic rock classes. Additionally, the approach was tested on a second dataset comprising petrographic microfacies images, demonstrating its effectiveness in multiclass geological structure classification. Validation on both datasets shows that the proposed method outperforms popular deep learning models and previous studies, achieving a 3% increase in accuracy. These results highlight that the proposed approach provides a robust and efficient solution for automated rock classification, offering significant advancements for geological research and real-world applications.

In this study, the neutron and gamma radiation-shielding properties of serpentinites from the Guleman ophiolite complex were investigated, and results were evaluated in comparison with rare earth element (REE) content. The linear and mass attenuation coefficients (LAC and MAC), half-value layer (HVL), mean free path (MFP), and effective atomic numbers (Z_eff) of serpentinite samples were experimentally measured in the energy range of 80.99–383.85 keV. Theoretical MAC values were calculated. Additionally, fast neutron removal cross-sections, as well as thermal and fast neutron macroscopic cross-sections, were theoretically determined. The absorbed equivalent dose rates of serpentinite samples were also measured. The radiation protection efficiency (RPE) for gamma rays and neutrons were determined. It was observed that the presence of rare earth elements within serpentinite structure has a significant impact on thermal neutron cross-sections, while crystalline water content (LOI) plays an influential role in fast neutron cross-sections. Moreover, it has been observed that the concentration of gadolinium exerts a more substantial influence on the macroscopic cross-sections of thermal neutrons than on those of fast neutrons. The research results reveal the mineralogical, geochemical, morphological and radiation-shielding properties of serpentinite rocks contribute significantly to new visions for the use of this naturally occurring rock as a geological repository for nuclear waste or as a wall-covering material in radiotherapy centers and nuclear facilities instead of concrete.

The accurate identification of rock types is crucial for understanding geological structures and planning mining activities. Therefore, the precise labeling of rock types is a fundamental requirement for researchers and industry experts in these fields. This study aims to identify rock types by segmenting thin-section rock images using advanced deep learning models. Commonly used models such as DeepLabv3+, SegFormer, ConvNext, and Mask2Former were evaluated to compare the performance of different segmentation models. Additionally, an improved version of Mask2Former was analyzed to enhance its performance. Post-segmentation enhancements with SLIC super pixel and morphological operations further improved boundary delineation. An improved version of Mask2Former achieved a validation accuracy of 91.26% and a mean Intersection over Union (mIoU) of 82.59%, representing an improvement of more than 5% over the base Mask2Former. Another significant aspect of the study is the detailed analysis of other models using the relevant dataset. The Quartz Feldspar Plagioclase (QAP) diagram was utilized for mineral identification, achieving a mineral recognition accuracy of 85.7%. These results indicate the robustness of the proposed approach, which exceeds the accuracy and mIoU of comparable methods reported in the literature. This study significantly enhances the effectiveness of image processing techniques for rock type identification. Furthermore, the detailed comparison of different models provides valuable guidance for researchers in selecting the most suitable model.

Serpentine (Mg₃Si₂O₅(OH)₄), like quartz, dolomite and magnesite minerals, is a versatile mineral group characterized by silica and magnesium silicate contents with multiple polymorphic phases. Among the phases composed of antigorite, lizardite, and chrysotile, lizardite and chrysotile are the most prevalent phases in the serpentinites studied here. The formation process of serpentinites, which arise from the hydrothermal alteration of peridotites, influences the ratio of light rare earth elements (LREE) to heavy rare earth elements (HREE). In serpentinites, the ratio of light rare earth elements (LREE)/heavy rare earth elements (HREE) provides insights into formation conditions, geochemical evolution, and magmatic processes. The depletion of REE compositions in serpentinites indicates high melting extraction for fore-arc/mantle wedge serpentinites. The studied serpentinites show a depletion in REE concentrations compared to chondrite values, with HREE exhibiting a lesser degree of depletion compared to LREE. The high ΣLREE/ΣHREE ratios of the samples are between 0.16 and 4 ppm. While Ce shows a strong negative anomaly (0.1–12), Eu shows a weak positive anomaly (0.1–0.3). This indicates that fluid interacts significantly with rock during serpentinization, and highly incompatible elements (HIEs) gradually become involved in the serpentinization process. While high REE concentrations indicate mantle wedge serpentinites, REE levels are lower in mid-ocean ridge serpentinites. The enrichment of LREE in the analyzed samples reflects melt/rock interaction with depleted mantle and is consistent with rock–water interaction during serpentinization. The gradual increase in highly incompatible elements (HIEs) suggests that they result from fluid integration into the system and a subduction process. The large differential thermal analysis (DTA) peak at 810–830 °C is an important sign of dehydration, transformation reactions and thermal decomposition, and is compatible with H₂O phyllosilicates in the mineral structure losing water at this temperature. In SEM images, chrysotile, which has a fibrous structure, and lizardite, which has a flat appearance, transform into talc as a result of dehydration with increasing temperature. Therefore, the sudden temperature drop observed in DTA graphs is an indicator of crystal form transformation and CO₂ loss. In this study, the mineralogical and structural properties and the formation of serpentinites were examined for the first time using thermo-gravimetric analysis methods. In addition, the mineralogical and physical properties of serpentinites can be recommended for industrial use as additives in polymers or in the adsorption of organic pollutants. As a result, the high refractory nature of examined serpentine suggests that it is well-suited for applications involving high temperatures. This includes industries such as metallurgy and steel production, glass manufacturing, ceramic production, and the chemical industry.

Serpentine (Mg₃Si₂O₅(OH)₄), like quartz, dolomite and magnesite minerals, is a versatile mineral group characterized by silica and magnesium silicate contents with multiple polymorphic phases. Among the phases composed of antigorite, lizardite, and chrysotile, lizardite and chrysotile are the most prevalent phases in the serpentinites studied here. The ΣLREE/ΣHREE ratios of the samples are between 0.16 and 4 ppm. While Ce shows a strong negative anomaly (0.1–12), Eu shows a weak positive anomaly (0.1–0.3). This indicates that fluid interacts significantly with rock during serpentinization, and Highly Incompatible Elements (HIEs) gradually become involved in the serpentinization process. The large differential thermal analysis (DTA) peak at 810–830 °C is an important sign of dehydration, transformation reactions and thermal decomposition, and is com-patible with H₂O phyllosilicates in the mineral structure losing water at this temperature. In SEM images, chrysotile, which has a fibrous structure, and lizardite, which has a flat appearance, trans-form into talc as a result of dehydration with increasing temperature. Therefore, the sudden tem-perature drop observed in DTA graphs is an indicator of crystal form transformation and CO₂ loss. In this study, the mineralogical and structural properties and the formation of serpentinites were examined for the first time using thermo-gravimetric analysis methods. In addition, the mineralogical and physical properties of serpentinites can be recommended for industrial use as additives in polymers or in the adsorption of organic pollutants. As a result, the high refractory nature of examined serpentine suggests that it is well-suited for applications involving high temperatures. This includes industries such as metallurgy and steel production, glass manufacturing, ceramic production, and the chemical industry.

The Fe skarn and vein-type Cu mineralization types are common in the Eastern Taurus Mountains. This study aims to determine the U-Pb geochronology of garnets of varying sizes within the skarn zone developed at the quartz diorite–marble contact zone in Ayazpınar, Pertek District, Tunceli Province, Turkey. Additionally, this study aims to determine the age of the skarnization and the types of inclusion minerals in the garnets. Faulting and magma emplacement along the thrust plane caused mineralization in the Eastern Taurus Mountains, especially at the marble and quartz diorite contact zone between the cities of Elazığ and Tunceli. The greenish garnets found in the Ayazpınar deposit are characteristic of distal skarns, while red or brown Pertek garnets are observed in the proximal skarns. The garnets typically feature a core–rim texture. The cores of the garnet crystals are large, reddish in color, and have a high REE (Ce, Pr) content. Moreover, the cores have higher Fe and lower Al ratios, alongside higher La, Ce, and Pr contents, than the rims. We propose that the compositional differences between the rims and the cores reflect the transition from oxidized REE- and Fe3+-rich liquids to liquids with lower REE and Fe3+ contents, producing the differences in the garnet colors. Green garnets show lower REE contents than brown garnets with Fe-rich cores. The skarn under study includes the following successively formed zones: diorite → epidote skarn → garnet–magnetite → pyrite–garnet–magnetite → calcite carbonate. Diopside, magnetite, and hematite, including small grains, are surrounded or enveloped by garnets. The U-Pb age of the mineralization is 74.1 ± 5 Ma, indicating that the mineralization occurred concurrently with the intrusion settlement.

Magmatik, hidrotermal ve metamorfik kayalarda yaygın olarak bulunan granat (Ca 2+, Mn2+,Fe2+/Mg2+ )3Y(Al 3+, Fe 3+, Cr 3+/V 3+)2(Si 4+)3O12 kimyasal formülü ile en yaygın minerallerden biridir.Granat minerali iki veya daha fazla uç bileşimin katı çözeltisidir. İzomorfik değişim gösteren granat,alüminyum serisi (Y pozisyonu Al3+ iyonu içerir) ve kalsiyum serisi (X pozisyonu Ca 2+ iyonu içerir) olarakiki seriyi kapsar. Alüminyum serisi, pirop, almandin ve spesartin, kalsiyum serisi ise grossular, andradit veuvarovit ile temsil edilir. Dünya çapında önemli bir demir, bakır, kurşun, çinko, tungsten, gümüş ve altınkaynağı olan skarn zonlarındaki granatlar, metasomatizma ve hidrotermal değişimi ile oluşabilir.Hidrotermal akışkan çevrimi ve kristal büyümesi, granatın hacim genişlemesi veya küçülmesi ilegerçekleşen değişimleri kapsar. Bu yapısal değişim çatlak dizini oluşturur. Çatlakların dağılımı ve granatçekirdeğine göre yönelimi, akışkan kimyasındaki değişim, zonlanma ve yeni mineral oluşumları petrolojideönemlidir. İnce bantlanma ve zonlanma aynı zamanda dissolusyon ve resorpsiyonu ve kimyasaldüzensizliği işaret eder. Kristal içindeki bu izotopik yapı, kristal kimyası, akışkan bileşimi ve fizikselkoşullardaki değişimle ne derece uyumlu olduğunun kanıtıdır. Bu koşullarda granat çatlaklarında farklıminerallerin gelişmesi olağandır. Yaygın olarak görülen magnetit sıcaklığın azalmasıyla akışkaniçerisindeki Fe iyonunun çökelmesine, diyopsit ise akışkanla kalsiyum getirimine işaret eder. Granatçatlakları boyunca izlenen kalsit, kuvars, epidot, diyopsit, klorit ve magnetitler meteorik yüzey suyu vehidrotermal akışkanların arasında gelişen karışım sonucu oluştuğu ve karışıma, gerilmeli ortamlarda kristalbüyüme sürecindeki sıcaklık değişimi sebep olur. Bu gerilme, çoğunlukla merkezden itibaren farklı yönlükırıkların oluşumunu sağlarken, radyal kırık dizini granat hacim gelişmesiyle ilgilidir.

We investigated serpentinites that contain a significant amount of magnetite, originating fromophiolites and tectonic melanges. Variations in the amount of magnetite were observed in serpentinitesdominated by antigorite. While some samples exhibited a prevalence of iron oxides, others contained almostnone. The Mg# [100*Mg/(Mg+Fe) atomic] values of the studied samples were found to range from 79 to88. However, for antigorite, the Mg# value can reach up to 92 in magnetite-rich rocks. In samples devoidof iron oxides, this value decreases, indicating the preservation of relic protolith textures.Serpentinites, despite having different formation mechanisms, typically result from the hydration ofperidotite. Hydration involves redox reactions, which yield brucite and magnetite. The formation ofmagnetite occurs primarily due to the preferential partitioning of Mg over Fe2+ in serpentine compared toolivine or orthopyroxene. Consequently, the excess iron, mainly derived from olivine, predominantlygenerates magnetite through redox reactions involving iron-rich brucite (Fe2+(OH)2) or reacting withavailable oxygen or product H2 (or CH4). The presence of magnesite and dolomite has been identified inthe samples. Based on the obtained findings, it can be inferred that rocks devoid of magnetite indeed containmagnetite produced by serpentinization, but ongoing reactions with fluid allowing iron back-reaction serveto re-equilibrate fO2 to preserve the entire rock's Mg#. Although this process may be challenged by theextended storage of antigorites at high P - T conditions, it appears to be a relatively closed system foroxides.