Mineralogical Analyses Research Articles

Chemical, Mineralogical, and Petrographic Analysis of the Mud Mortar from Fort Ikoma Historical Building in Serengeti National Park, Tanzania

The restoration of historical buildings especially the Fort Ikoma in Serengeti National Park, Tanzania requires knowing the material properties used in their construction by characterizing the composition and properties of the mortar to inform the sustainable restoration strategies. Hence, the objective of this paper was to investigate the chemical, mineralogical, and petrographic analysis of the mud mortar from the Fort Ikoma historical building in Serengeti National Park, Tanzania using appropriate standard methods. The results indicated predominant compositions by weight of mud mortar through chemical analysis were silica (59.82%), alumina (20.42%), and Iron (III) oxide (11.07%), which contributed to the higher pozzolanic activity (91.31%) and cementitious properties (Cementitious Index of 46.76) of the historical mud mortar. Mineralogical analysis revealed that a high amount of quartz (38%), nacrite (17%), and other materials such as albite, chlorite, and nepheline put up the ability of mud mortar to resist environmental pressures. The findings contribute to awareness of historical building materials and provide the technical basis for restoring the Fort Ikoma historical building in Serengeti National Park, Tanzania, and similar historical buildings.

Grossite-bearing refractory inclusions from reduced CV chondrites: Mineralogical and oxygen isotopic constraints on the parent body alteration history

We report the results of coordinated mineralogical, microstructural, and oxygen isotopic analyses of grossite-bearing refractory inclusions from reduced CV (Vigarano type) chondrites to obtain a more complete picture of secondary parent body alteration processes and conditions. Grossite (CaAl4O7) occurs in cores of nodules in fine-grained Ca,Al-rich inclusions (CAIs) that likely represent aggregates of nebular condensates. In many occurrences, grossite has been partially replaced by hercynite [(Fe,Mg,Zn)Al2O4], which displays complex microstructures and compositions, and magnetite nanoparticles. The alteration of grossite was a crystallographically-controlled, fluid-driven process that occurred via partial dissolution of grossite and subsequent precipitation of hercynite and magnetite during short-lived and low-temperature metasomatic alteration on the CV chondrite parent body. The constituent phases of grossite-bearing CAIs show heterogeneous oxygen isotopic compositions, with grossite and perovskite displaying systematically 16O-depleted compositions (Δ17O= − 12 ‰ to − 1 ‰) relative to uniformly 16O-rich hibonite and spinel (Δ17O= − 25 ‰ to − 21 ‰). Melilite is variably 16O-depleted (Δ17O= − 25 ‰ to − 2 ‰). The observed oxygen isotopic distribution is interpreted as a result of mineralogically controlled oxygen isotopic exchange with an 16O-poor fluid on the CV chondrite parent body. Collectively, the presence of limited fluids played an important role in preferential alteration of grossite to hercynite and magnetite and various degrees of 16O depletion in grossite, perovskite, and melilite during thermal metamorphism. We conclude that, among refractory phases in the inclusions, grossite was the most susceptible to metasomatic reactions with Fe-rich fluids and the second most susceptible, after perovskite, to oxygen isotopic exchange with an 16O-poor fluid during the thermal history of the CV chondrite parent asteroid.

Sustainable and cleaner production of a porous geopolymer support based on metakaolin and natural calcium oxide

The field of engineering today, mainly civil engineering, given population growth and urbanization, is experiencing permanent changes, thereby implying the use of a sustainable and, above all, less polluting alternative. The present work deals with the study of the effects of the calcium-phosphate network in the geopolymeric matrix in an acidic environment (P2O5/H2O = 0.06 and 0.12) using metakaolin (MK) and calcined oyster shells (COs). Kaolin (K) and oyster shells (respectively heat treated at 700 and 900 °C), metakaolins and geopolymers (produced at room temperature according to the molar ratios P2O5/H2O = 0.06 and 0.12) have were characterized using chemical, thermal (TGA/DSC), mineralogical (XRD) analyzes and Fourier Transform Infrared Spectroscopic Analysis (FTIR). In addition, the physical and mechanical properties of the geopolymers (specimen appearance, setting time, linear shrinkage, water absorption and compressive strength) were determined. It was found that kaolin and oyster shells contain mostly kaolinite and calcium oxide respectively. However, the mineralogical analysis of MK shows a dome reflecting the presence of an amorphous phase favourable to geopolymerisation. From these results, we note that: the appearance of the geopolymer specimens is accentuated by the efflorescence and the presence of pores. The setting times of the pastes for the two solutions decreased with the addition of COs powder, due to the presence of calcium phosphate crystalline phases within the materials such as monetite and brushite which tend to accelerate network consolidation. Linear shrinkage also decreased with the addition of COs powder. On the other hand, with the addition of COs, the water absorption increase at the ratio 0.06 while they decrease at 0.12, due to the presence of pore within the geopolymers. As for the compressive strengths, they decrease with the addition of the COs powder, due to the weakening of the geopolymeric network by monetite and brushite. In conclusion, at high concentrations (P2O5/H2O = 0.12), COs (responsible for the formation of monetite and brushite in acidic environments) powder acts as a porogen. Given the presence of pores in the materials and their relatively high resistance compared to other studies, these materials could be used in engineering as sensors, insulators (thermal, electrical and acoustic).

Provenance Analysis of the Northern Offshore Mud Area of the Shandong Peninsula, China, Spanning the Last 2000 Years

The mud area in the northern offshore of the Shandong Peninsula constitutes a dynamic source–sink system in China’s continental shelf and is a hotspot for research. However, the provenance of the sediments remains controversial, and the depositional environment is not yet fully understood. This paper performed accelerator mass spectrometry 14C dating, grain-size analysis, clay mineralogic analysis, and geochemical analysis of the ZZ04 sediment core. The results showed that this core primarily comprises silt and clay, reflecting weak sedimentary hydrodynamic conditions and stable deposition. The clay mineral assemblage—illite, smectite, chlorite, and kaolinite—indicates strong physical weathering. The provenance of the mud area was mainly from the Yellow River, Shandong Peninsula rivers, and Yangtze River, highlighting its multi-source characteristics. The smectite/(illite + chlorite) ratio in the ZZ04 core serves as a mineralogical indicator of the East Asian summer monsoon (EASM). Eight significant East Asian winter monsoon (EAWM) intensifications were identified, correlating with global cooling events similar to those at 1.89, 1.4, 1.03, and 0.62 thousand years ago. During the EAWM period, the coastal current and the Yellow Sea warm current play crucial roles in the transportation of matter and heat flux in the mud area. In contrast, during the EASM period, the sediments are predominantly sourced from the Shandong Peninsula rivers, contributing terrigenous materials shaped by chemical weathering.

Tiebas Castle’ tuiles vernissées: Characterization, raw clay provenance, and manufacturing technology

Tiebas Castle was built between 1254 and 1264 as a royal residence of the kings of Navarre. The Castle was decorated with architectural luxuries imported from the French court. Some decorative elements of this French style are the polychrome roof tiles, called tuiles vernissées; and the glazed floor tiles, called carreaux de pavement. Both are the unique that have been found in the Iberian Peninsula. Elemental and mineralogical analysis allowed us to distinguish two different types of pastes that were used for both tuiles vernissées and carreaux de pavement: yellowish and reddish. The reddish paste was composed mainly of quartz, and to a lesser extent of haematite and illite. The yellow pastes were very rich in calcite and other calcium-bearing minerals (gehlenite, anorthite, diopside or wollastonite) and poorer in quartz and haematite. The different colour tones of the yellow paste samples allowed them to be classified into five subgroups (YP-1, YP-2, YP-3, YP-4, and YP-5). This classification turned out to coincide with a somewhat different mineral composition. The study of the mineral phases newly formed (gehlenite, anorthite, diopside and wollastonite) or destroyed (illite) during firing allowed us to estimate the maximum firing temperature of each of the subgroups. The temperature ranges for each subgroup were as follows: 750–800 °C (YP-5), 850–900 °C (YP-4), 900–925 °C (YP-3), 925–950 °C (YP-2), and 950–1000 °C (YP-1). The study of its possible raw materials allowed us to identify that the yellow pastes from tuiles vernissées and carreaux de pavement were prepared from a mixture of two clays. One of them was the decalcification clay (A15 clay) with which they also made the reddish pastes. The other component of the mixture was the marl from Castle hill. The proportion that the artisans used of both raw materials was 1:2 (twice as much marl as decalcification clay).

Fungal carbonatogenesis process mediates zinc and chromium removal via statistically optimized carbonic anhydrase enzyme

IntroductionWith rapid elevation in population, urbanization and industrialization, the environment is exposed to uncontrolled discharge of effluents filled with broad-spectrum toxicity, persistence and long-distance transmission anthropogenic compounds, among them heavy metals. That put our ecosystem on the verge or at a stake of drastic ecological deterioration, which eventually adversely influence on public health. Therefore, this study employed marine fungal strain Rhodotorula sp. MZ312369 for Zn2+ and Cr6+ remediation using the promising calcium carbonate (CaCO3) bioprecipitation technique, for the first time.ResultsInitially, Plackett–Burman design followed by central composite design were applied to optimize carbonic anhydrase enzyme (CA), which succeeded in enhancing its activity to 154 U/mL with 1.8-fold increase comparing to the basal conditions. The potentiality of our biofactory in remediating Zn2+ (50 ppm) and Cr6+ (400 ppm) was monitored through dynamic study of several parameters including microbial count, CA activity, CaCO3 weight, pH fluctuation, changing the soluble concentrations of Ca2+ along with Zn2+ and Cr6+. The results revealed that 9.23 × 107 ± 2.1 × 106 CFU/mL and 10.88 × 107 ± 2.5 × 106 CFU/mL of cells exhibited their maximum CA activity by 124.84 ± 1.24 and 140 ± 2.5 U/mL at 132 h for Zn2+ and Cr6+, respectively. Simultaneously, with pH increase to 9.5 ± 0.2, a complete removal for both metals was observed at 168 h; Ca2+ removal percentages recorded 78.99% and 85.06% for Zn2+ and Cr6+ remediating experiments, respectively. Further, the identity, elemental composition, functional structure and morphology of bioremediated precipitates were also examined via mineralogical analysis. EDX pattern showed the typical signals of C, O and Ca accompanying with Zn2+ and Cr6+ peaks. SEM micrographs depicted spindle, spherical and cubic shape bioliths with size range of 1.3 ± 0.5–23.7 ± 3.1 µm. Meanwhile, XRD difractigrams unveiled the prevalence of vaterite phase in remediated samples. Besides, FTIR profiles emphasized the presence of vaterite spectral peaks along with metals wavenumbers.ConclusionCA enzyme mediated Zn2+ and Cr6+ immobilization and encapsulation inside potent vaterite trap through microbial biomineralization process, which deemed as surrogate ecofriendly solution to mitigate heavy metals toxicity and restrict their mobility in soil and wastewater.

A multi-disciplinary approach for uranium exploration using remote sensing and airborne gamma-ray spectrometry data in the Gebel Duwi area, Central Eastern Desert, Egypt

Uranium exploration plays a pivotal role in meeting global energy demands and advancing nuclear technology. This study presents a comprehensive approach to uranium exploration in the Gebel Duwi area of the Central Eastern Desert of Egypt, utilizing remote sensing and airborne gamma-ray spectrometric data. Multispectral remote sensing techniques, including Principal Component Analysis (PCA), Minimum Noise Fraction (MNF), and Band Ratioing (BR), are employed to identify lithological units and hydrothermal alteration zones associated with uranium deposition, such as iron oxides, argillic, propylitic, and phyllic alterations. Additionally, airborne gamma-ray spectrometry data provide insights into the spatial distribution of radioelements, including uranium (eU), thorium (eTh), and potassium (K), as well as radioelement ratios (eU/eTh, eU/K, and eTh/K). The uranium migration index map (eU-(eTh/3.5)) and the F-parameter map (K*(eU/eTh)) have been generated to investigate the movement of uranium within various geological zones and characterize anomalous uranium concentrations. Statistical analyses, including mean (X), standard deviation (S), and coefficient of variability (C.V.), are conducted to identify uranium-rich zones. The integration of these datasets enables the generation of a uranium potential map highlighting areas of elevated concentrations indicative of uranium mineralization. Field observations and mineralogical analyses of collected samples validate our findings, confirming the presence of minerals associated with uranium mineralization in mapped high-potential areas. The significance of minerals like Fe-Chlorite, Fe-Mg-Chlorite, ferrihydrite, goethite, calcite, muscovite, dolomite, actinolite, vermiculite, and gypsum in indicating potential uranium mineralization processes underscores the importance of our results.

Enhanced erosion and silicate weathering of the West African craton during the late Cretaceous cooling evidenced by mineralogical and Hf[sbnd]Nd isotope proxies

The evolution of oceanic temperatures between the Turonian and the K/T boundary indicates a long-term cooling coincident with a decrease of atmospheric CO2 levels, yet the cause of climate cooling at that time still remains debated. In this study, we evaluated the possible implication of enhanced silicate weathering as a sink for atmospheric CO2 by applying paired NdHf isotope measurements to detrital clay records from the West African margin. The use of this novel proxy for chemical weathering intensity (ΔɛHf(t)clay) was complemented by additional mineralogical and major-trace element analyses in order to investigate the variability of mechanical erosion patterns and further explore potential linkages between tectonics, weathering and climate during the late Cretaceous.Our ΔɛHf(t)clay data suggest more intense silicate weathering on the West African Craton during the Santonian to the middle Campanian period, coincident with enhanced physical erosional inputs as inferred from higher Quartz/Clays and Feldspar/Clays ratios. This observation suggests that the shift towards intensified chemical weathering at that time was driven by enhanced mechanical erosion, possibly related to a moderate tectonic event on the West African craton. Evidence for increasing kaolinite contents and higher ΔɛHf(t)clay values during the Maastrichtian point towards more hydrolysing conditions, inducing either destabilization of older Mesozoic lateritic material or favouring the development of kaolinite-rich soils.Overall, this study was compared with several new data of chemical weathering evolution along the south Atlantic margins, adding new insights on tectonic-weathering-climate interactions during the late Cretaceous, suggesting a possible link between silicate weathering feedbacks and global cooling at that time.

Carbon isotope stratigraphy and biostratigraphy, and associated organic carbon deposition during the Late Cenomanian to Early Turonian in the Tarfaya Basin, Morocco

The Cenomanian-Turonian (C/T) boundary event, also known as Oceanic Anoxic Event 2 (OAE2), is characterised by significant organic carbon preservation and a positive carbon isotope excursion that is recorded globally in sedimentary strata. In this study of the Tarfaya Basin, Morocco, three outcrop sections were logged - at Lagguing East, Tazra, and En-Naila, dated from Late Cenomanian to Early Turonian. New dating, based on ammonites and planktic foraminifera, combined with high-resolution δ13C isotope stratigraphy, yields a more precise delineation of the C/T boundary in the studied section. A total of 99 samples were collected for combined sedimentological, mineralogical, and geochemical analyses to allow a better understand of the palaeoenvironments of deposition and interpret controlling factors on organic enrichment. Five lithofacies have been identified, all indicative of a relative deep marine setting. Variations in lithofacies can be correlated with relative sea level changes, which align with the global eustatic curve.The OAE2 interval comprises black mudstones that signal anoxic conditions, leading to significant organic matter (OM) preservation, even though they appear weathered in the studied section. Notably, organic matter-rich mudstones were evident during the post-OAE2 Early Turonian maximum marine transgression. Trace element enrichment in these organic-rick mudstones indicates that organic matter accumulation was accompanied with increased sea surface productivity and associated with oxygen-depleted bottom water conditions, which facilitated organic matter preservation and enrichment. Upwelling has also been previously described as a process to deliver nutrients to the shelf, enhancing productivity. Some units with depleted organic content are the result of dilution from continental derived clastics. Others may originally have had high TOC, but were influenced by weathering or diagenetic process, changing from the typical black mudstones to yellow in colour. The identified carbon isotopic values and organic carbon enrichment in the C/T strata of the Tarfaya Basin reflect signals of global perturbations in the carbon cycles.

Geological, physiochemical, mineralogical, and rheological characterizations of clay deposits in Northeast Libya

ABSTRACT This study was conducted on bentonite deposits in Um Al Rozm and Ain Al Ghazala areas that lie between Latitudes º32 “00 ‘30 and º32 “33 ‘30 N and Longitudes º23 “00 ‘30 and º23 “20 ‘30 E in Northeast Libya. The objective of this study is the assessment of geological, physiochemical, mineralogical, and rheological properties and the potentiality of utilizing these rocks as drilling fluids for oil and gas wells. Chemical and mineralogical analyses were performed by XRF and XRD, respectively. Rheological properties are investigated before and after the treatment process by adding additive materials such as Na2CO3 and CMC. The chemical analysis results of bentonite showed a discrepancy in the proportions of the major components. The results after the treatment process for bentonite in Um Al Rozm exhibit rheological properties consistent with those stipulated by API and other standard bentonites, but for Ain Al Ghazala, the results are unsatisfactory. Mineral analysis of bentonite from the two areas revealed a difference in the mineral composition. The bentonite of the Um Al Rozm area is Na-bentonite, while the bentonite of the Ain Al Ghazala area is Ca-bentonite, whose rheological properties aren’t acceptable as drilling fluid properties stipulated by API.

Granulometric and Mineralogical Characterization of Sands from the Middle Course of the Kasai River (Ilebo Territory, Kasai Province, DRC)

This study addresses sediment dynamics within the fluvial system of the middle Kasai Basin, specifically between Ilebo town (pk605) and the confluence with the Loange River (pk525). The primary aim is to characterize the granulometric and mineralogical evolution of sand bars in the Kasai River, which pose navigational challenges in this section of the basin. The study seeks to answer the following question: How do the granulometric and mineralogical characteristics of sands transported by the middle course of the Kasai River evolve? The research employs laboratory granulometric techniques. Twenty sand samples were collected from sand bars along the middle and navigable course of the Kasai River during the flood recession period, ranging from upstream to downstream. Sieving was conducted using an AFNOR-type sieve column, followed by sedimentometric analyses and the calculation of various Folk & Ward textural parameters using the Excel program Gradistat. Additionally, six samples underwent automated mineralogical analysis using a QEMSCAN FEG Quanta 650. Granulometric analysis revealed that the sands from the middle course of the Kasai River are unimodal, with fine to medium grains in the granulometric fraction ranging from 186.2 µm to 426.8 µm. Most of these sands are moderately to well graded, with grains showing granulometric symmetry and, less commonly, fine asymmetry. Their kurtosis is largely mesokurtic, with occasional leptokurtic and platykurtic characteristics, indicating multiple depositional environments. The study demonstrates that the evolution of these granulometric parameters is uneven along the middle course of the Kasai River, though overall, the parameters exhibit limited variation. This suggests minimal and regular sediment inputs, consistent with the relative regularity of granulometric variations in environments characterized by free sedimentation. Automated mineralogical analysis identified a diverse mineralogical assemblage, dominated by quartz, followed by calcite, iron oxides, orthoclase, plagioclase, and kaolinite. Additionally, a group of minerals that do not exceed the 0.55% threshold—such as illite, apatite, ilmenite, muscovite, chlorite, biotite, montmorillonite, rutile, pyrophyllite, siderite, zircon, and dolomite—was identified. Consequently, the mineralogical evolution is not uniform throughout the middle course of the Kasai River, showing a sawtooth variation. This study clarifies the evolution of the granulometric parameters of Kasai River sands, which are influenced by the river's hydrodynamic regime. It also elucidates the mineralogical evolution, linked to the petrographic nature of source areas, which are distributed based on their mechanical resistance to abrasion, chemical alteration, and the morphology of the riverbed. The findings from this research contribute significantly to the field of sedimentology and integrated river management

Origin of porosity in evaporite platform dolostone in the middle Cambrian Shaelek Formation, NW Tarim Basin, China: constraints from petrology, mineralogy and geochemistry

The extensive middle Cambrian evaporite platform dolostone represents a significant area for hydrocarbon exploration in the Tarim Basin with recent advances indicating promising exploration prospects. However, owing to its considerable depth and the limited exploration, the genesis and distribution of evaporite-related dolostone reservoirs from the middle Cambrian remain poorly understood. This study includes detailed field investigations along with petrological, mineralogical and geochemical analyses to characterise the secondary porosity of the middle Cambrian Shaelek Formation evaporite platform dolostone and to explore the origin of the diagenetic fluids responsible for these features. The results show that gypsum dissolution vugs are the main secondary porosity in the evaporite platform dolostone reservoirs, with their development and distribution strongly controlled by sedimentary facies. Meteoric dissolution during the penecontemporaneous period is responsible for this secondary porosity. The frequent fluctuation in sea-levels and the transient exposure of the dolostone reservoirs provide favourable conditions for the dissolution of unstable gypsum. The multiple stages of calcite filling in the vugs result from supersaturated precipitation from fluids during the late stage of meteoric diagenesis. Variations in δ13C, δ18O and rare earth element compositions between the two types of calcite reflect different stages of fluid evolution and varying degrees of water–rock reaction. The vug-filling fluorite is of non-hydrothermal genesis but results from the highly evaporative concentrated seawater and terrigenous input. The highly concentrated F– in evaporative seawater, combined with F– from fluvial input (if any) during subaerial exposure, most likely provides the F– necessary for fluorite precipitation. A model of reservoir formation and evolution has been established that will be beneficial for hydrocarbon exploration and prediction of the deeply buried Cambrian evaporite platform dolostone reservoir.

Formation and degradation of textural pedofeatures in soils of ancient tropical coastal plains in southeastern Brazil

Textural features in soils are defined as having a distinct granulometric composition compared to the surrounding groundmass. Among these, clay coatings are found in various pedo-environments, covering a range of climatic conditions, from wetter regions to semiarid areas. This study aimed to understand how textural features in ancient coastal plain soils can reveal mechanisms of their pedogenetic evolution and how this relates to environmental transformations. Three soil profiles were studied at different points in a toposequence, representing the upper, middle, and lower thirds. The study area is located in the municipality of Seropédica, in the state of Rio de Janeiro, southeastern Brazil. Morphological, physical, chemical, mineralogical, and micromorphological analyses were conducted on the selected profiles. Acrisols, formed in free-draining conditions, were later transformed into Planosols due to base level oscillation and the percolation of brackish solutions through the soils. The pedogenetic model proposed in this study involves the following stages: i) Clay formation by in situ mineral weathering, mainly of phyllosilicates, with pseudomorphization of the structures. ii) Destruction of the pseudomorphized structures by pedoplasmation with proximal migration of clay and genesis of textural features of coating and filling. iii) Partial and episodic saturation of the base of the profile with solutions enriched in sodium of a fluvial-marine nature. iv) Dispersion of the clays, leading to the destruction of the textural features and soil micromass, accompanied by relative sand enrichment and E horizon formation. v) Local lowering of the surface and smoothing of the base of the slopes. This transformation model is unprecedented for the southeastern region of Brazil, increasing the evolutionary complexity of soil genesis in areas of ancient fluvial-marine plains.

Gypsum on Mars: A Detailed View at Gale Crater

Gypsum is a common mineral at Gale crater on Mars, currently being explored by the Mars Science Laboratory (MSL) rover, Curiosity. In this paper, we summarize the associations of gypsum with other sulfate minerals (bassanite, anhydrite, jarosite, starkeyite, and kieserite) from the lowest levels of the crater’s northern moat zone (Aeolis Palus) up through ~0.8 km of the stratigraphic section in the lower slopes of the sedimentary mound developed around the central peak, Aeolis Mons (informally, Mount Sharp). The analysis is based on results from the CheMin X-ray diffraction instrument on Curiosity, supplemented with information from the rover’s versatile instrument suite. Gypsum does not occur with the same frequency as less hydrous Ca-sulfates, likely, in most cases, because of its dehydration to bassanite and possibly to anhydrite. All three of these Ca-sulfate phases often occur together and, along with other sulfates, in mixed assemblages that are evidence of limited equilibration on a cold, dry planet. In almost all samples, at least one of the Ca-sulfate minerals is present, except for a very limited interval where jarosite is the major sulfate mineral, with the implication of more acidic groundwater at a much later time in Gale crater’s history. Although observations from orbit reveal a sulfate-rich surface, currently active dark basaltic dunes at Gale crater have only small amounts of a single sulfate mineral, anhydrite. Gale crater has provided the most complete mineralogical analysis of a site on Mars so far, but the data in hand show that Gale crater mineralogy is not a blueprint with planet-wide application. The concurrent study of Jezero crater by the Mars 2020 mission and comparisons to what is believed to be the most extensive deposit of gypsum on Mars, in the dune fields at the north polar ice cap, show significant diversity. Unraveling the stories of gypsum and other sulfates on Mars is just beginning.

Microbialitic third-order Rupelian cycles of the Kuwait Formation, and their global correlative surfaces

The microbialites identified in the Kuwait Formation (also known as the Kuwait Group) at the Jal Az-Zor escarpment were largely misclassified as calcrete beds. Through detailed geological field observations, five distinct microbial beds have been identified and are found to occur at the end of each depositional cycle. Over these cycles, three main facies have been identified; these are bioturbated cross-bedding, calcareous sandstones, and microbial facies. The combination of field and petrographic analyses indicates that these sequences are dominated by siliciclastic facies, with microbial facies primarily manifesting as thrombolites or laminites, with the former being more common. Mineralogical analysis of the microbial facies indicate that over 60% of this facies is composed of calcite, and energy dispersive spectroscopy measured a significant percentage of organic carbon that reached up to 39.3% wt. Scanning electron microscope imagery of the microbial facies identified filamentous bacteria and flagellates as the principal constituents of these microbial assemblages. The bioturbated cross-bedding facies is found to be deposited in an estuarine central bay, the calcareous sandstone facies is deposited in an estuary mouth bar system that transitions laterally into a shoreface setting, and the microbial facies is deposited in a peritidal setting. Strontium isotope (87Sr/86Sr) dating of the five microbial beds indicates that these beds were deposited at 33.99 Ma, 32.6 Ma, 31.5 Ma, 30 Ma, and 29 Ma, respectively, suggesting that the associated sequences are of a Rupelian 3rd order hierarchy. Our analysis correlates the Jal Az-Zor sequences with New Jersey's Oligocene oxygen isotope sequence boundaries and the La2004 obliquity nodes, suggesting a continued uplift rate during the Rupelian age at the studied area. This article challenges the assumption that the Oligocene success is absent in Kuwait and the surrounding region, opening the door for further assessment of these deposits.

Main Characteristics of the Geological Structure of the Evaporite Formation of the Amu Darya Syneclise

The geological structure of the evaporite formation in the Amu Darya syneclise is a complex system that provides valuable insights into the region's geological history and economic potential. The study aims to analyse the main characteristics of the geological structure of the evaporite formation in the Amu Darya syneclise to expand knowledge of the geological and environmental history of the region and to identify the potential of these deposits for various applications. The methods used for this study included geological mapping, mineralogical analysis, stratigraphic analysis and geochemical research. The study identifies three distinct water-bearing horizons within the evaporite complex: Sharaplinsky, Yolotan, and Sakar. These horizons exhibit varying characteristics in terms of composition, water content, and distribution across the basin. Geomorphological manifestations, such as salt lakes and salt marshes, play a crucial role in understanding the ecological and geological history of the region. The evaporite formation holds substantial economic importance, hosting valuable resources including salts, oil, and gas. This geological structure supports regional industrial development, job creation, and overall economic growth. The study also highlights the need for further research into the geology and geomorphology of the Amu Darya syneclise to better understand the formation and dynamics of evaporite deposits and their role in the region’s current environmental and economic sectors. The study emphasizes the need for efficient technologies and methods for resource extraction and management to ensure sustainable development and minimize environmental impact. The research provides crucial data for optimizing mineral extraction strategies and developing effective natural resource management approaches. It underscores the importance of understanding the geological structure for sustainable ecological and economic development in the region. The practical significance of this study is a basis for developing more effective natural resource management strategies based on an understanding of the geological processes of evaporite sedimentation in the Amu Darya syneclise, which is key to the sustainable development of the region’s ecological and economic systems.

Mineral chemistry, petrography and crystallization conditions of the Middle Eocene Kazıkbeli Pluton (Eastern Pontides, NE Türkiye)

The Eastern Pontides host a diverse suite of plutonic rocks spanning a wide range of ages and compositions. Among these, the Middle Eocene Kazıkbeli pluton, located in the Kürtün district of Gümüşhane, stands out due to its distinctive petrological characteristics. This study aims to unravel the petrological implications of petrographic and mineral chemical data to constrain the physicaydınçakırochemical conditions (temperature, pressure, oxygen fugacity) under which the Kazıkbeli magma crystallized and was emplaced. By integrating mineral chemical data, we seek to quantify emplacement pressure, crystallization temperature, and oxygen fugacity. A comprehensive understanding of the genetic relationships and physicochemical properties of the Kazıkbeli pluton rocks, as determined through geological, petrographic and mineral chemistry, is crucial for elucidating the geological evolution of the Eastern Pontides. The Kazıkbeli Pluton exhibits a predominant NE-SW orientation and encompasses an area of roughly 46 km². Modal mineralogical analysis reveals a compositional spectrum ranging from gabbroic diorite to monzogranite, with granodiorite and tonalite being the most prominent rock types. Textural variations encompass fine- to medium-grained, porphyritic, poikilitic, and occasionally graphic textures. The primary mineral assemblage of the pluton comprises plagioclase, orthoclase, quartz, amphibole, biotite, and Fe-Ti oxides. Accessory minerals include zircon, apatite, sphene, and allanite. Plagioclases are labradorite to oligoclase (An26 to An66) in composition. K-feldspar minerals exhibited an orthoclase composition (Or80 to Or97). All amphiboles belong to the calcic amphibole field and exhibit a magnesio-hornblende (Mg#=0.63-0.73) composition. Biotites crystallized as solidified melt products with compositions between annite and phlogopite endmembers, plotting close to the magnesium-rich (Mg#=0.52-0.58) end of the phlogopite solid solution series. Calculated crystallization temperatures derived from amphibole and biotite data range from 712°C to 824°C. Pressure estimations calculated using amphibole-plagioclase, amphibole and biotite suggest a range of 0.04 to 2.06 kbar. Oxygen fugacity (ƒO2) values calculated using amphibole and biotite fall between -12.5 and -16.1. Amphibole-based water content estimations indicate a range of 3.7% to 5.7% for the pluton. Biotite compositions within the studied Kazıkbeli pluton rocks exhibit characteristics suggestive of a potential mantle origin. Geobarometric calculations based on mineral chemistry data with geological and petrographic features indicate the emplacement of the Kazıkbeli Pluton at relatively shallow depths within the crust (~1 to 8 km).

Discovering Halite Traces on a Victim’s Clothing through a Forensic Geoscience Analytical Approach: A Suspicious Case in Italy

This suspect case focuses on investigating the presence of halite (NaCl) crystals on the clothing of a deceased individual to determine whether they resulted from immersion in seawater or residual absorption after immersion (i.e., the crystals were left on the clothing after contact with the victim’s wet body). Thirteen clothing samples were collected from various garments worn by the victim and were subjected to optical stereomicroscopy, Scanning Electron Microscopy (SEM), coupled with Energy Dispersive Spectroscopy (EDS), and Simultaneous Thermal Analysis (STA). Optical stereomicroscopy revealed numerous white-colored, vitreous, and greasy luster microcrystals dispersed between fabric fibers, with higher concentrations observed near the hem seams and metal rivets. These microcrystals exhibited predominantly cubic and irregular morphologies. Additionally, sandy particles and organic elements, such as plant fragments and micro seashells, were detected, indicative of coastal environment exposure. SEM-EDS analysis confirmed the presence mainly of sodium and chlorine in stoichiometric ratios consistent with halite, with crystals exhibiting amorphous, needle-shaped, or cubic morphologies. Furthermore, STA analysis identified weight loss events attributed to organic decomposition and halite decomposition at high temperatures, corroborating SEM-EDS findings. The distribution and characteristics of halite crystals, along with other trace elements, support the hypothesis of immersion in seawater while wearing clothing. Specifically, the higher concentrations of halite crystals near thicker fabric portions and metal rivets suggest slower drying rates and longer evaporation times, indicative of immersion rather than residual absorption after swimming. This finding not only helps in determining the victim’s exposure to seawater but also establishes a methodology for distinguishing between different sources of halite residue on clothing. Overall, the comprehensive mineralogical characterization of halite crystals on clothing samples, using best practices of forensic mineralogy, provides valuable forensic insights related to the circumstances that led to the victim’s death. This approach aided investigators in reconstructing the sequence of events, enhancing the accuracy of forensic reconstructions. Moreover, this study contributes to the broader field of forensic geoscience by demonstrating the practical applications of mineralogical analysis in criminal investigations, potentially guiding future research and improving investigative techniques in similar cases.

Geochemistry and clay mineralogy of shales in the Sulu Orogenic Belt, East China: suggestion for continental weathering during an Early Cretaceous hyperthermal interval

ABSTRACT Understanding past weathering–climate feedback mechanisms under greenhouse conditions has significance for guiding the development of climate mitigation strategies. The continental paleoweathering state of Early Cretaceous shales in the Sulu Orogenic Belt of East China during a hyperthermal interval related to oceanic anoxic event 1a (OAE1a) was investigated via geochemical and clay mineralogical analyses of shale samples. The resulting diagrams of ternary 15Al2O3–Zr–300TiO2 discrimination, Th/Sc and Zr/Sc show that the geochemical composition was mainly controlled by source composition. This is supported by observations of low Zr contents, high indexes of compositional variability (ICV; > 1), and micropetrological characteristics. All samples showed narrow SiO2/Al2O3 and (Fe2O3 + MgO)/Al2O3 ranges that were within the predicted weathering trends of the ternary A-CN-K diagram, indicating that the shale geochemistry was not influenced by silicification and K-metasomatism. The chondrite-normalized rare-earth-element pattern suggests that all samples had the same felsic igneous parent rock. The geochemistry of whole rocks and their silicate fractions indicates that the shale had low chemical indexes of alteration (CIA) but high ICV values compared to post-Archean Australian Shale, indicating low sediment maturity and extremely weak chemical weathering in the source terrane and/or sedimentary basin under hot-dry conditions. Moreover, the clay minerals in the shale were mainly illite, suggesting low mineral weathering. Thus, during the OAE1a-related hyperthermal interval, chemical weathering was relatively weak in some mid-latitude arid inland areas. This may be mainly due to aridification decreasing water–rock reactions. Chemostratigraphic analysis suggests that the CIA, Ga/Rb, and Rb/Sr values of shales from the upper strata of the Yangjiazhuang and Shuinan formations were greater than those from lower strata. Moreover, the opposite trend in K2O/Al2O3 ratios was found. These indices suggest gradual increases in chemical weathering as the climate changed from hot-dry to warm-humid. In contrast, proxy indices of shale from the Zhifengzhuang Formation showed the opposite trend, suggesting a gradual decrease in chemical weathering as the climate changed from warm-humid to hot-dry. Considering the composition of the clay minerals, it is speculated that continental weathering was dependent on atmospheric humidity rather than temperature under the extreme greenhouse conditions, resulting in ineffective climate regulation by chemical weathering. This comprehensive study advances our understanding of the weathering–climate feedback mechanism under greenhouse regimes.

Fractionation and leaching of Cd, Cu, Fe, Pb, and Zn from smelter residues of an old environmental liability in Argentina

An integrated chemical and mineralogical characterization approach was applied to smelter wastes collected from 50-year-old dump sites in Argentina. Characterization included pseudo-total element concentrations, acid generation/neutralization potential, sequential extractions, pH-dependent leaching kinetics, and mineralogical analysis of all residues. These analyses provided detailed information on the reactivity of the minerals in the waste material and associated metal release. Cadmium and Zn were the elements of greatest environmental concern due to their high mobility. On average, the release of Zn and Cd in pH-dependent leaching essays reached 17.6% (up to 5.24 mg g−1) and 52.7% (up to 0.02 mg g−1) of the pseudo-total content, respectively. Moreover, Cd and Zn were also the metals that showed the higher proportions of labile fractions associated to the adsorbed and exchangeable fraction (60–92% for Cd and 19–38% for Zn). Since Cd and Zn concentrations in the residue are not high enough to form their own minerals, a large proportion of these elements would be weakly adsorbed on Fe oxyhydroxides. In contrast, the low release of Cu, Pb and Fe would be associated with these elements being incorporated into the crystalline structure of insoluble or very poorly soluble minerals. Lead is incorporated into plumbojarosite and anglesite. Copper was mainly in association with Fe oxyhydroxides and may also have been incorporated into the plumbojarosite structure. The latter could act as a sink especially for Pb under the acidic conditions of the smelter residue. Despite the elevated concentrations of Pb observed in the residue, it showed a very low mobility (≈0.1%), indicating that it is mostly stabilized. Nevertheless, the smelter residue is a continuous source of metals requiring remediation.