Search Results (93)

Numerical simulations enable us to couple multiphase flow and geochemical processes to evaluate how sequestration impacts brine chemistry and reservoir properties. This study investigates these impacts during CO₂ storage at the San Juan Basin CarbonSAFE (SJB) site. The hydrodynamic model was calibrated through history-matching, utilizing data from saltwater disposal wells to improve predictive accuracy. Core-scale simulations incorporating mineral interactions and equilibrium reactions validated the model against laboratory flow-through experiments. The calibrated geochemical model was subsequently upscaled into a field-scale 3D model of the SJB site to predict how mineral precipitation and dissolution affect reservoir properties. The results indicate that the majority of the injected CO₂ is trapped structurally, followed by residual trapping and dissolution trapping; mineral trapping was found to be negligible in this study. Although quartz and calcite precipitation occurred, the dissolution of feldspars, phyllosilicates, and clay minerals counteracted these effects, resulting in a minimal reduction in porosity—less than 0.1%. The concentration of the various ions in the brine is directly influenced by dissolution/precipitation trends. This study provides valuable insights into CO₂ sequestration’s effects on reservoir fluid dynamics, mineralogy, and rock properties in the San Juan Basin. It highlights the importance of reservoir simulation in assessing long-term CO₂ storage effectiveness, particularly focusing on geochemical interactions. Full article

The Parnassos-Ghiona region constitutes the most significant bauxite-bearing province in Greece, with a well-documented history of research highlighting its geotectonic complexity and its importance for bauxite exploitation. Among the three principal bauxite horizons, the lower stratum (b1) remains the least thoroughly investigated, in contrast to the upper (b3) and intermediate (b2) strata. This disparity is primarily attributed to the limited surface exposure of the b1 horizon within the broader Parnassos-Ghiona Unit. The present study examines the characteristics of the b1 strata through an integrated mineralogical and geochemical approach. For the first time, the confirmed presence of rare earth element (REE) minerals within the b1 horizon is documented. Geochemical proxies, including REE distribution patterns and elemental ratios, indicate a genetic relationship with igneous parent rocks of intermediate to basic affinity. Full article

Significant uranium exploration breakthroughs have been achieved in the eolian deposits of the uranium reservoirs in the southwestern part of the Ordos Basin. The redox environment remains a crucial factor in controlling the migration and precipitation of uranium. This study, through rock mineralogical observations and hydrocarbon gas composition analysis, combined with the regional source rock and basin tectonic evolution history, reveals the characteristics of the reducing medium and the mineralization mechanisms involved in uranium ore formation. The Lower Cretaceous Luohe Formation uranium reservoirs in the study area exhibit a notable lack of common reducing media, such as carbonaceous debris and pyrite. However, the total hydrocarbon gases in the Luohe Formation range from 2967 to 20,602 μmol/kg, with an average of 8411 μmol/kg—significantly higher than those found in uranium reservoirs elsewhere in China, exceeding them by 10 to 100 times. Due to the absence of other macroscopically visible organic matter, hydrocarbon gases are identified as the most crucial reducing agent for uranium mineralization. These gases consist predominantly of methane and originate from the Triassic Yanchang Formation source rock. Faults formed during the Indosinian, Yanshanian, and Himalayan tectonic periods effectively connect the Cretaceous uranium reservoirs with the oil and gas reservoirs of the Triassic and Jurassic, providing pathways for the migration of deep hydrocarbon fluids into the Cretaceous uranium reservoirs. The multiphase tectonic evolution of the Ordos Basin since the Cenozoic has facilitated the development of faults, ensuring a sufficient supply of reducing media for uranium reservoirs in an arid sedimentary context. Additionally, the “Replenishment-Runoff-Drainage System” created by tectonic activity promotes a continuous supply of uranium- and oxygen-bearing fluids to the uranium reservoirs, resulting in a multi-energy coupling mineralization effect. Full article

This study investigates the mineral composition of the lunar Dryden Crater using Moon Mineralogy Mapper (M³) data. A RGB false-color composite reveals distinct pyroxene, anorthosite, and possibly spinel distribution patterns. Orthopyroxenes, excavated from deep crustal layers, dominate steep slopes, while plagioclase-rich materials align with magma ocean models of lunar crustal formation. Minor clinopyroxenes indicate impact melt origins. While space weathering and shock metamorphism pose analytical challenges, integrating spectral data with geological context elucidates the crater’s complex history. The resulting mineral distribution map supports targeted exploration during upcoming lunar missions, resource prospecting and resource utilization initiatives within this geologically complex region. Full article

The manuscript of the Mineralogical lessons for the 1824–1825 course being held at the Royal Cabinet of Natural History had been found in the Archivo General de Palacio (AGP; Madrid, Spain) by the priest Donato García, who replaced Christian Herrgen and held the chair of Mineralogy until 1853. The historic document increases the scant record of this type of documentary source from a period still little known in relation to the state of Mineralogy teaching and allows for a closer understanding of this discipline. This article presents a thorough analysis to identify the collaboration between Professor García and his pupil, José Musso y Valiente, as well as the authorship of the manuscript in connection with the notes of this pupil, due to the absence of any indication in the historical document, with the objective of producing a mineralogy work on mineralogy in the Spanish language. To this end, the manuscript has been examined and compared with the Mineralogy notes of José Musso Pérez-Valiente, Donato García’s pupil, which are preserved in the Lorca Municipal Archive (Murcia, Spain). By comparing Musso’s notes with the manuscript from the Archivo General de Palacio, the idea is reinforced that the former were corrected by Donato García, who eventually left a copy in the Royal Library, corresponding to the one preserved in the AGP, constituting the first record of Donato García’s authorship in relation to Mineralogy. Full article

This study presents the first detailed investigation of the petrography, mineralogy, and depositional environment of Messinian gypsum lithofacies outcropping on the western side of the Crati Basin (Calabria, Southern Italy), focusing on three sections: Castelluccio, Striscioli, and Piretto. The different localities preserve in situ gypsum accumulation (laminar gypsum and gypsiferous mudstone) and clastic gypsum deposits (nodular, gypsarenite and gypsrudite) formed during the second stage (5.60–5.55 Ma) of the Messinian Salinity Crisis (MSC). Observation and analyses of macro-, meso- and nanoscale reveal a complex climatic variability and depositional history that reflect different environmental conditions, from shallow-water evaporitic environments to deep basin settings affected by slope failures. The data highlights the influence of tectonic activity on facies distribution within the basin. Overall, this study emphasizes the importance of climatic and geological controls on gypsum deposition, offering a detailed interpretation of the Crati Basin’s evaporitic history and contributing to the broader understanding of Mediterranean Messinian evaporites. Full article

The initial nucleus of gemstones at the Natural History Museum of the University of Florence (Italy) is linked to the significant collection of the Medici family, who began it as early as the 15th century. The present research aims to study this collection in order to (1) comprehensively review the archival and catalogue information available; (2) identify the mineralogical species correctly; and (3) gather information on the potential provenance of the gem deposits. To address these objectives, fifty gems were investigated using entirely non-invasive methods, ensuring the preservation of the collection’s precious and historical value. All specimens underwent autoptic observation and micro-Raman analysis, while a selection was further examined using PIXE-PIGE to characterise their chemical composition, including trace elements. The gems were attributed to seven mineral species: emerald, topaz, grossular, cordierite, quartz, orthoclase, and tourmaline. One gem was identified as a fake, made of glass and likely produced in the 17th century. Twenty-nine of the historical attributions in the catalogue were found to be incorrect and were subsequently revised. In some cases, the trace elements and mineral inclusions identified in the gems enabled the determination of potential provenance deposits, which were then compared with the available archival information. Full article

Investigation of the critical metal elements in coal and coal-bearing strata has become one of the hottest research topics in coal geology and coal industry. Coal-hosted Ga-Al-Li-REE deposits have been discovered in the Jungar and Daqingshan Coalfields of Inner Mongolia, China. Gallium, Al, and Li in the Jungar coals have been successfully extracted and utilized. This paper reviews the discovery history of coal-hosted Ga-Al-Li-REE deposits, including contents, modes of occurrence, and enrichment origin of critical metals in each coal mine, including Heidaigou, Harewusu, and Guanbanwusu Mines in the Jungar Coalfield and the Adaohai Coal Mine in the Daqingshan Coalfield, as well as the recently reported Lao Sangou Mine. Gallium and Al in the coals investigated mainly occur in kaolinite, boehmite, diaspore, and gorceixite; REEs are mainly hosted by gorceixite and kaolinite; and Li is mainly hosted by cholorite. Gallium, Al, and REEs are mainly derived from the sediment-source region, i.e., weathered bauxite in the Benxi Formation. In addition, REE enrichment is also attributed to the intra-seam parting leaching by groundwater. Lithium enrichment in the coals is of hydrothermal fluid input. The content of Al₂O₃ and Ga in coal combustions (e.g., fly ash) is higher than 50% and ~100 µg/g, respectively; concentrations of Li in these coals also reach the cut-off grade for industrial recovery (for example, Li concentration in the Haerwusu coals is ~116 µg/g). Investigations of the content, distribution, and mineralization of critical elements in coal not only provide important references for the potential discovery of similar deposits but also offer significant coal geochemical and coal mineralogical evidence for revealing the geological genesis of coal seams, coal seam correlation, the formation and post-depositional modification of coal basins, regional geological evolution, and geological events. Meanwhile, such investigation also has an important practical significance for the economic circular development of the coal industry, environmental protection during coal utilization, and the security of critical metal resources. Full article

This study presents a comprehensive analysis and radiocarbon dating of historical mortar and plaster samples from the San Salvatore—Massino Visconti complex in Piedmont, Northern Italy. Mortar samples and one charcoal sample were collected from various areas within the complex’s lower chapels. Samples were selected and characterized by means of a multi-analytical approach in order to draw inferences about their compositional, mineralogical, and microstructural features. The identification of hydromagnesite and magnesite in the mortar samples suggests the usage of magnesian binder mortar, potentially affecting radiocarbon dating due to its slower carbonation kinetics when compared to calcitic mortars. To mitigate this effect, a purification method was developed involving thermal treatment at 550 °C to isolate datable binding fractions. The results yielded reliable radiocarbon ages consistent with historical context, shedding light on construction materials dating from the 12th to 16th centuries. The study also challenges previous notions by demonstrating the feasibility of radiocarbon dating for magnesian mortars, opening new perspectives for dating such materials. These findings offer valuable insights into the construction history and material composition of the complex, corroborating historical information. Full article

The origin of Oligocene sediments in the Bengal Basin and associated tectonic setting remain poorly understood. This study investigates the framework mineralogy and major element geochemistry of the Barail Group sandstones from the Sylhet Trough within the Bengal Basin to clarify the provenance and tectonic history of the Oligocene. Modal analysis (Q₈₃F₇L₁₀) and geochemical data support a classification of sublitharenite to subarkose, some with Fe enrichment. The heavy mineral assemblage is dominated by opaque minerals, followed by ultrastable minerals with zircon > tourmaline > rutile. The sub-angular to sub-rounded sand grains with a compositionally moderate mature nature suggest that the sediments were deposited close to the source area. The mineralogical and geochemical provenance discrimination diagram suggests contributions from felsic igneous, sedimentary/metasedimentary, and low-grade metamorphic sources, with detritus derived from the Indian craton and proto-Himalaya region. Data suggest moderate to intense chemical weathering, indicative of low relief and a sub-humid to humid climate in the source area. The tectonic analyses indicate that the Bengal Basin transitioned from a predominantly passive margin to an active tectonic margin setting during the Oligocene. Full article

New data obtained from core samples of two boreholes and dredged samples from the Alba Guyot in the Magellan Seamount Trail (MST), Western Pacific, including the ⁴⁰Ar/³⁹Ar age determinations of basanite, and the mineralogy of basanite, tuff, tuffite, mantle-derived inclusions in basanite and tuff (lherzolite xenolith and Ol, Cpx, and Opx xenocrysts), and calcareous nannofossil biostratigraphy, have implications for the guyot′s development and history. Volcanic units in the upper part of the Alba Guyot main edifice and its Oma Vlinder satellite, at sea depths between 3600 and 2200 m, were deposited during the Cretaceous 112 to 86 Ma interval. In the following ~60 myr, the Alba Guyot became partly submerged and denuded with the formation of a flat summit platform while the respective fragment of the Pacific Plate was moving to the Northern Hemisphere. Volcanic activity in the northeastern part of the guyot summit platform was rejuvenated in the Miocene (24–15 Ma) and produced onshore basanitic volcanoes and layers of tuff in subaerial and tuffite in shallow-water near-shore conditions. In the Middle-Late Miocene (10–6 Ma), after the guyot had submerged, carbonates containing calcareous nannofossils were deposited on the porous surfaces of tuff and tuffite. Precipitation of the Fe-Mn crust (Unit III) recommenced during the Pliocene–Pleistocene (<1.8 Ma) when the guyot summit reached favorable sea depths. The location of the MST guyots in the northwestern segment of the Pacific Plate near the Mariana Trench, along with the Miocene age and alkali-basaltic signatures of basanite, provide first evidence for petit-spot volcanism on the Alba Guyot. This inference agrees with the geochemistry of Cenozoic petit-spot basaltic rocks from the Pacific and Miocene basanite on the Alba Guyot. Petit-spot volcanics presumably originated from alkali-basaltic melts produced by decompression partial melting of carbonatized peridotite in the metasomatized oceanic lithosphere at the Lithosphere–Asthenosphere Boundary level. The numerous volcanic cones with elevations of up to 750 m high and 5.1 km in basal diameter, discovered on the Alba summit platform, provide the first evidence of voluminous Miocene petit-spot basanitic volcanism upon the Cretaceous guyots and seamounts of the Pacific. Full article

Developments in scanning electron microscopy (SEM) have introduced instant live coloured SEM images based on elemental composition. Here, we use a technique utilising a Unity BEX detector system, with collection speeds up to 100 times faster than typical standard energy-dispersive X-ray (EDX) analysis systems, to obtain large area backscattered and elemental composition maps of heavy mineral (HM) suites from a sample from an Oligocene fluvio-deltaic system in the Central Myanmar Basin. The fast X-ray collection rate and a high-resolution backscattered (BSE) detector allow for rapid imaging of polished blocks, thin sections, and stubs. Individual HM species can be rapidly classified, allowing for the subsequent collection of compositional and morphological metrics. In addition, the identification of grains such as zircon and apatite allow for further analysis by cathodoluminescence (CL) to identify and record the presence of growth zonation, which is critical for further U-Pb geochronology and thermochronology, using fission track analysis of apatite, zircon, and titanite. The sample used in this study contains a diverse heavy mineral suite due to the complex tectonic history of Myanmar, juxtaposing multiple metamorphic basement terranes alongside volcanic arcs and obducted ophiolites. This, along with the textural and mineralogical immaturity of the sediments themselves (governed by short transport systems and the rapid weathering of the sources), means that a wide variety of heavy mineral species can be identified and tested using this new technique, which provides a time-efficient method in comparison to traditional optical techniques. As the Unity BEX detector is located at the polepiece, it is relatively insensitive to working distance; in addition, the geometry of paired X-ray detectors on either side of the polepiece (at 180°) means that the system is also capable of fully characterising individual particles, on uncut and unpolished grain mounts, without artefacts such as particle shadowing. The development of a more comprehensive heavy mineral EDX database (library) will improve the accuracy of this new technique, as will the correlation with other techniques such as Raman spectroscopy. Full article

Since prehistoric times, indigenous residents of southwest British Columbia, Canada, collected water-worn nephrite specimens from the gravel bars along the Fraser River, using the stone for the manufacture of tools that were widely traded with other tribes. Allochthonous nephrite occurs in another geologic setting. Late Pleistocene continental glaciers transported nephrite and many other rock types from western Canada to northwest Washington State, producing extensive sediment deposits that border the Salish Sea coast in Whatcom and Island Counties, Washington. This material was little utilized by indigenous residents, but “black jade” specimens are prized by modern collectors. The depositional history and mineralogy of this material has received little attention. X-ray diffraction and SEM/EDS analyses indicate that the Salish Sea “black jade” is a form of impure nephrite that probably originated from metamorphism of a mafic igneous parent material (metabasite). The texture consists of prismatic amphibole crystals (ferro-actinolite) set in a matrix rich in plagioclase feldspar. Pyrite inclusions are locally present. A second material, sometimes erroneously labelled “muttonfat jade” by amateur collectors, consists of an intermixture of quartz and sillimanite. Full article

Baoshan is a world-class skarn Cu-polymetallic deposit located at the junction of the Nanling and Qin-Hang metallogenic belts in China. While there has been extensive research on the mineralogy and geochemistry of skarn deposits, studies on the fluid characteristics and evolutionary history from the early to late skarn stages in such deposits are still limited. In this study, we analyzed garnet and pyroxene from the early skarn stage and scheelite from the late skarn stage of the Baoshan deposit. We distinguished two generations of garnet (Grt1 and Grt2), one generation of pyroxene, and three generations of scheelite (Sch I, Sch II, and Sch III) on the basis of mineral assemblages and microscopic characteristics. Grt1 appears coarse-grained, and Grt2 cuts through Grt1 as veinlets. In Grt1, the andradite end-member increases from the core to the rim, while the grossular portion decreases (Ad_35–36Gr_59–61Sp_3–4 to Ad_59–61Gr_36–37Sp_2–3), and in Grt2, the andradite end-member significantly increases (Ad_41–73Gr_25–55Sp_2–3). Grt1 and Grt2 have similar trace element compositions, with enrichment in Zr and depletion in Nb and Hf, depletion in LREE, enrichment in HREE, and weak negative Eu anomalies. Pyroxene coexists with Grt1 and is similarly cut by Grt2, with its composition mainly being diopside (Di_82–99Hd_0.6–15Jo_0–3.2). Sch I and Sch II appear as anhedral to subhedral grains, while Sch III is predominantly found in veinlets. In Sch I and Sch II, most REEs enter the scheelite lattice via the Na-REE coupled substitution mechanism, with a smaller portion substituting Ca vacancies. In Sch III, the substitution mechanism involving Ca site vacancies may dominate. During the early skarn stage, the oxygen fugacity of the fluid gradually decreased from Grt1 and pyroxene to Grt2. In the late skarn stage, fluid oxygen fugacity remains stable from Sch I and Sch II to Sch III in shallow parts but significantly decreases in deeper parts. The garnet and pyroxene from the Baoshan deposit align with typical skarn Cu deposit compositions, while scheelite in the late skarn stage shows Sch I, Sch II, and shallow Sch III as skarn-type and deep Sch III as vein-type scheelite. Early skarn stage fluids were weakly acidic. Sch I, Sch II, and Sch III originated from fluids related to the Baoshan granite porphyry, with Sch III also showing evidence of water–rock interaction. This study reconstructed the fluid evolution history from the early to late skarn stages at the Baoshan deposit, providing insights into the ore-forming processes of other skarn deposits. Full article

Throughout history, the architecture of worship structures has been shaped based on different cultures and belief systems during the Roman, Seljuk, Anatolian Principalities, and Ottoman periods. Additionally, it is understood that the sociocultural and ritual structure in which the worship place is built plays a significant role in church architecture. In province of Ordu, rich in historical and cultural heritage, historical structures outside the city center have not been well preserved. In recent years, neglected historical structures have been restored through various methods with public investments, aiming to reintegrate them into urban life. Through chemical and mineralogical (by microscopy) examinations aimed at determining the types of historical structural materials used for this purpose, the preservation of historical structures in Ordu province and their transfer to future generations is targeted. Church structures, holding a distinct significance in the region’s history, exhibit various characteristics in terms of location, climate, and sociocultural and ritual aspects in the Black Sea region. In this regard, the restoration of the historical Taşbaşı Church in the Altınordu district of Ordu province has been carried out considering scientific techniques and methods, serving as a guide for similar studies in the region in terms of laboratory analysis, studies, planning, project development, and implementation stages. Full article