Geological Framework Research Articles

From Geoheritage to Geosites at the Oeste Aspiring Geopark (Portugal)

Geoheritage and geosites have been assessed as part of the work supporting the application of the Oeste Aspiring Geopark, in West Central Portugal, for an UNESCO Global Geopark. The geological framework is presented, describing the regional evolution of the Lusitanian Basin, related to the Mesozoic opening of the North Atlantic, since the Late Triassic until the Late Cretaceous, followed by the Cenozoic inversion of the basin, related to the Alpine orogeny. The overall geodiversity of the territory is described, and the main geological highlights are presented.Within the scope and objectives of a Geopark, the criteria for the definition of geosites are presented and discussed. Geoconservation, geoeducation and geotourism have been considered to define 80 geosites, with different characteristics, purposes, relevance and potential. Six different encompassing themes have been defined, each one with a specific storytelling. Geoconservation issues are also addressed, showing the importance of protection strategies for the geosites at a local scale.

Three-stage niobium mineralization at Bayan Obo, China.

The Chinese Bayan Obo deposit is a world-class rare earth element (REE) deposit with considerable niobium (Nb) and iron (Fe) resources. A complete genetic understanding on all metals is fundamental for establishing genetic models at Bayan Obo. With extensive research being focused on REE enrichment, the timing and controls of Nb enrichment remain unresolved at Bayan Obo, which is mainly due to the challenges in dating, i.e. multistage thermal events, fine-grained minerals with complex textures and the rare occurrence of uranium-enriched minerals with mature dating methods. Based on robust geological and petrographic frameworks, here we conducted ion probe uranium-lead (U-Pb) dating of ferrocolumbite to unravel the timing, hence the genesis of Nb mineralization. Three types of hydrothermal ferrocolumbites-key Nb-bearing minerals-are identified based on their textures and mineral assemblages. They yield U-Pb ages of 1312±47 Ma (n=99), 438±7 Ma (n=93), and 268±5 Ma (n=19), respectively. In line with deposit geology, we tentatively link the first, second and third stage Nb mineralization to Mesoproterozoic carbonatite magmatism, ubiquitous early Paleozoic hydrothermal activity, and Permian granitic magmatism, respectively. While quantifying the contribution of metal endowment from each stage requires further investigation, our new dates highlight that multi-stage mineralization is critical for Nb enrichment at Bayan Obo, which may also have implications for the enrichment mechanism of Nb in REE deposits in general.

An Object‐Based Approach to Differentiate Pores and Microfractures in Petrographic Analysis Using Explainable, Supervised Machine Learning

AbstractPetrographic observations are vital for carbonate pore‐typing, linking geological frameworks to petrophysical behavior. However, current petrographic pore typing is manual, with the qualitative to semi‐quantitative results not easily fitted into quantitative subsurface characterization. Some recent studies have automated this process using supervised machine learning (ML) and deep learning (DL), focusing on simple pore morphological features, and have reported high classification accuracies for several complex pore types. However, there are concerns about the validity of these studies due to conceptual and technical flaws in their collective approach. This study was aimed at a more fundamental problem, classifying between open microfractures and open pores in petrographic thin sections using an object‐based approach and explainable supervised ML. We analyzed 18 carbonate thin sections from the USA, numerically representing them using five shape features: compactness, aspect ratio, extent, solidity, and formfactor. Using a labeled data set of 400 microfractures and 400 pores, we evaluated nine of the most widely used supervised models. All models showed high testing accuracies (89.58%–90.42%). Interestingly, complex non‐linear models did not significantly outperform simpler linear ones. Compactness and aspect ratio were the most informative features. However, the labeled data sets did not reflect the overall data set's complexity, which suggested that high accuracies in similar studies might be due to curated data sets rather than accounting for the true complexity of carbonate pore systems. The study concludes that simple shape features are ineffective for classifying carbonate pore types. It is hoped that this study will provide a foundation for more robust artificial intelligence‐assisted pore typing.

Multi-granularity retrieval of mineral resource geological reports based on multi-feature association

Massive geologic report contains all kinds of multimodal geologic data information (geologic text, geologic maps, geologic tables, etc.), which contain a lot of rich geologic basic knowledge and expert experience knowledge about rocks and minerals, stratigraphic structure, geologic age, geographic location, and so on. Accurate retrieval of specific information from massive geologic data has become an important need for geologic information retrieval. However, the majority of existing research primarily revolves around extracting and associating information at a single granularity to facilitate geological semantic retrieval, which ignores many potential semantic associations, leading to ambiguity and fuzziness in semantic retrieval. To solve these problems, this paper proposes a multi-granularity (document-chapter-paragraph) geological information retrieval framework for accurate semantic retrieval. The framework firstly extracts topic feature information, spatiotemporal feature information, figure and table feature information based on the multi-granularity of geological reports. Then, an improved apriori algorithm is used to mine and visualize the associations among the feature information to discover the semantic associations of the geological reports at multiple levels of granularity. Finally, experiments are designed to validate the application of the proposed multi-granularity information retrieval framework on the accurate retrieval of geological reports. The experimental results show that the proposed multi-granularity information retrieval framework in this paper can dig deeper into underlying geo-semantic information and realize accurate retrieval.

Geochemistry of Granites in Panggong Lalat, Gua Musang, Kelantan

Granites are among the most significant rock formations in the Earth’s crust and play a crucial role in various geological processes. This study focuses on examining the geology and granitic rock formations in Panggong Lalat, Gua Musang, Kelantan through field surveys, geological mapping, and geochemical analysis for better understand the geological framework and characteristics of granite in this area. The findings indicate that the lithology of the study area includes granitoids, well-bedded limestone, volcanic rocks, fine-grained sediments, and meta-sedimentary rocks. Petrographic analysis of five samples identified three granitoid types: quartz-rich granitoid, quartz alkali feldspar syenite, and alkali feldspar granite, classified using the IUGS scheme. The X-ray Fluorescence (XRF) data reveals that both samples exhibit typical felsic granite compositions, with high SiO₂ contents in AF 01 (61.61%) and 60.72% in AF02. However, AF 02 displays higher concentrations of TiO₂, FeO, and MnO, suggesting a greater contribution of mafic minerals compared to AF 01. Additionally, CaO content is slightly higher in AF02, indicating a more significant presence of plagioclase feldspar, while AF01 is enriched in K₂O. The Inductively Coupled Plasma - Optical Emission Spectrometry (ICP-OES) data further reinforce the distinction between AF 01 and AF 02. Both samples are enriched in Rare Earth Elements (REE), particularly Ce, Er, and La. A F02 shows significantly higher concentrations of Ce (213.85 ppm) and Er (7554.11 ppm) compared to AF 01 (166.12 ppm for Ce and 3047.54 ppm for Er), indicating a stronger REE enrichment in AF 02.The distribution of Heavy Rare Earth Elements (HREE) is more abundant than that of Light Rare Earth Elements (LREE), with Er exhibiting the highest concentration and Nd the lowest.

A new method of the hydrocarbon secondary migration research: Numerical simulation

A three-dimensional invasion percolation simulation model is introduced and integrated into a novel three-dimensional geological modeling framework based on the “unit element” theory to study secondary hydrocarbon migration. Leveraging the computational efficiency inherent in the invasion percolation theory, the simulation method is effectively applied to basin-scale hydrocarbon migration using finely discretized grids. Sensitivity analysis demonstrates the substantial influence of geological parameters including structural configuration, sedimentary facies, and pressure, on simulation results. Noteworthy observations from this study encompass: (1) The intricate influence of sedimentary facies and petrophysical properties characteristics on hydrocarbon migration and accumulation patterns within structural and lithological traps. Favorable petrophysical attributes in the carrier beds enhance the likelihood of accumulation in the structural traps, while lithological traps are prevalent in less conducive carrier beds. (2) The significant impact of sand bodies exhibiting favorable petrophysical attributes, such as channels, on migration and accumulation profiles. This underscores the necessity of incorporating sedimentary facies and rock attributes into oil and gas resource exploration. (3) The pronounced effects of overpressure magnitude and direction on hydrocarbon migration and accumulation dynamics. (4) Optimal strategies for oil and gas resource exploration necessitate a comprehensive assessment of rock attributes, overpressure considerations, and sedimentary facies. The practical implementation of this methodology is demonstrated in an actual exploration project within China's Junggar Basin. The simulation results closely align with established oil recovery data and facilitate predictive identification of promising exploration areas. This indicates the methodology is applicable to all petroleum systems similar to Junggar Basin. Through practical applications, the development of a scientifically rigorous three-dimensional geological model for the study area, coupled with numerical simulations of oil and gas migration, facilitates the elucidation of accumulation patterns. This approach aids in identifying pivotal factors such as sand body distribution, internal structural composition, permeability attributes, and fracture behavior, which collectively influence oil and gas migration. Furthermore, by correlating insights obtained from oil and gas discoveries in wells, a deeper understanding of carrier bed properties and their geological evolution is attained.

Digital Geological Map of the Upper Laja River Basin, Guanajuato, Mexico

A new geological map of the Upper Laja River Basin at 1:200,000 scale is presented, covering an area of ∼11,600 km2 in the northern part of Guanajuato. This map was edited based on local and regional geological studies available in the literature, photo interpretations, field verification of contacts and faults and structural data acquisition. The main objective of this map is to provide a regional geological framework for future local geological and hydrological studies in the region. It displays the geology of the basin, divided into seven chronostratigraphic groups, as well as the main faults that shape the basin. In contribution to the geological knowledge of the area, five new U-Pb ages are presented, obtained from samples collected at the eastern and western edges of the basin.

Sulfur and Carbon–Oxygen Isotopic Geochemistry and Fluid Inclusion Characteristics of the Yolindi Cu-Fe Skarn Mineralization, Biga Peninsula, NW Turkey: Implications for the Source and Evolution of Hydrothermal Fluids

The current study sought to investigate the physiochemical conditions and fluid evolution within the Yolindi Cu-Fe skarn mineralization located in the Biga Peninsula, NW Turkey. This was accomplished through a comprehensive investigation of geological and mineralogical data, along with isotopic analyses of sulfur (δ34S), carbon (δ13C), and oxygen (δ18O) of sulfide and calcite minerals, respectively, as well as fluid inclusion data pertaining to various minerals (e.g., andradite, quartz, and calcite). The Yolindi area features a complex geological framework, including the Paleozoic Kalabak Group (which includes the Torasan, Yolindi, and Sazak formations) and the Triassic Karakaya Complex. These formations were subsequently intruded via Early Miocene Şaroluk granitoids and Hallaçlar volcanics. Skarn formation is zoned into endoskarn and exoskarn types (being categorized into proximal, intermediate, and distal zones), with distinct mineral assemblages indicating concentric and contact metamorphic alteration patterns around the western part of Şaroluk granitoid intrusion in contact with the Torasan formation. The ore mineralogy and paragenesis suggest three distinct stages of evolution: an initial phase of prograde metasomatism characterized by the formation of magnetite and pyrite alongside anhydrous calc-silicate minerals; a subsequent phase of retrograde alteration marked by the formation of epidote, actinolite, and scapolite, accompanied by the occurrence of chalcopyrite and specular hematite; and finally, a post-metasomatic stage involving oxidation processes that led to the development of secondary mineral assemblages containing cerussite, covellite, and malachite. Sulfur isotopes (δ34S) of sulfides from endoskarn (from +0.27 to +0.57‰VCDT) to intermediate exoskarn (from −9.44 to −5.46‰VCDT) zones indicate a diverse sulfur source, including magmatic, sedimentary, and possibly organic matter. δ34S values in hydrothermal fluids suggest a magmatic–hydrothermal origin, with endoskarn and proximal zone fluids showing a slight negative signature and intermediate zone fluids indicating a strong influence from organic-rich or metamorphic sulfur reservoirs. Carbon and oxygen isotopic compositions (δ13C and δ18O) of calcite revealed a progression from marine carbonate signatures in marble samples (from +1.89 to +2.23‰VPDB; from +21.61 to +21.73‰VSMOW) to depleted values in prograde (from −6.0 to +0.09‰VPDB; from +6.22 to +18.14‰VSMOW) and retrograde skarns (from −3.8 to −2.25‰VPDB; from +0.94 to +3.62‰VSMOW), reflecting interactions with high-temperature magmatic fluids and meteoric water mixing. The fluid inclusions in prograde minerals generated under the conditions of fluid boiling exhibited high temperatures, reaching up to 412 °C, and salinities up to 26 wt.% NaCl equivalent. Conversely, the fluid inclusions in retrograde minerals, which were generated due to fluid mixing, exhibited lower temperatures (with an average of 318 °C) and salinities with an average of 4.9 wt.% NaCl equivalent. This indicated that the cooler and more diluted fluids mix with meteoric waters and interact with organic materials in the host rocks. This suggests a multifaceted origin involving various sources and processes. Therefore, this study concluded that the skarn mineralization in the Yolindi area resulted from complex interactions between magmatic, metamorphic, and meteoric fluids, reflecting a dynamic ore-forming environment with implications for the regional metallogeny of Cu-Fe skarn deposits.

Geothermal Play Fairway Analysis, Part 2: GIS methodology

Play Fairway Analysis (PFA) in geothermal exploration originates from a systematic methodology developed within the petroleum industry and is based on a geologic, geophysical, and hydrologic framework of identified geothermal systems. We tailored this methodology to study the geothermal resource potential of the Snake River Plain and surrounding region, but it can be adapted to other geothermal resource settings. We adapted the PFA approach to geothermal resource exploration by cataloging the critical elements controlling exploitable hydrothermal systems, establishing risk matrices that evaluate these elements in terms of both probability of success and level of knowledge, and building a code-based ‘processing model’ to process results.A geographic information system was used to compile a range of different data types, which we refer to as elements (e.g., faults, vents, heat flow, etc.), with distinct characteristics and measures of confidence. Discontinuous discrete data (points, lines, or polygons) for each element were transformed into continuous interpretive 2D grid surfaces called evidence layers. Because different data types have varying uncertainties, most evidence layers have an accompanying confidence layer which reflects spatial variations in these uncertainties. Risk layers, as defined here, are the product of evidence and confidence layers, and are the building blocks used to construct Common Risk Segment (CRS) maps for heat, permeability, and seal, using a weighted sum for permeability and heat, but a different approach with seal. CRS maps quantify the variable risk associated with each of these critical components. In a final step, the three CRS maps were combined into a Composite Common Risk Segment (CCRS) map, using a modified weighted sum, for results that reveal favorable areas for geothermal exploration. Additional maps are also presented that do not mix contributions from evidence and confidence (to allow an isolated view of evidence and confidence), as well as maps that calculate favorability using the product of components instead of a weighted sum (to highlight where all components are present). Our approach helped to identify areas of high geothermal favorability in the western and central Snake River Plain during the first phase of study and helped identify more precise local drilling targets during the second phase of work. By identifying favorable areas, this methodology can help to reduce uncertainty in geothermal energy exploration and development.

Bedform characteristics and implications for seafloor-bottom current interactions along the Wild Coast shelf, South Africa

Antecedent conditions and geology influence bedform dynamics and other sea-bed bottom current interactions on the continental shelf. However, the nature of this influence has not been well constrained, particularly on current-swept shelves. A variety of bedforms (narrow and broad sediment ribbons, comet marks and subaqueous dunes) are revealed by high resolution multibeam bathymetry and side scan sonar surveys of the mid-to outer “Wild Coast” shelf along the east coast of South Africa. The bedforms demonstrate a relationship to the geological framework of the shelf.The various bedforms occur in conjunction with bedrock-incised valleys and topographic depressions filled with transgressive sediment and bounded laterally by prominent rocky outcrops. These sediment sources are siphoned and mobilised by the Agulhas Current to create the contemporary shelf bedforms. Mechanisms of bedform development are associated with the interplay between the loci of sediment supply and associated grain size on the one hand and the current velocity and pathway of the Agulhas Current on the other.Sediment ribbons form parallel to the flow path of the Agulhas Current in narrow or broad forms that can be differentiated primarily by sediment grain size. With increased sediment availability from nearby bedrock-bound depocenters these transition along shelf to 2D dunes. A cross-shelf transition to 3D dunes on the outer shelf is marked by increased current velocity, grain size and decreased sediment availability outside of rock-bound depocenters. Rock outcrops affect current velocity and flow paths sufficiently to favour localised deposition over sediment stripping from the shelf. Comet mark forms develop from interactions between availability of finer sediment and perturbations of current flow paths by rock outcrops. This creates conditions that favour localised sediment scouring over deposition.With variability in sediment size, grain size and current flow, dunes fluctuate between active (sharp crested), inert (round crested) and degraded (flat crested) states. A lack of available sediment to replenish outer shelf dunes sees prolonged stasis, eventual dune splitting and breakdown under progressive current influence. Mid-shelf dunes have a greater capacity to recover from periods of stasis and short-term degradation due to greater availability of sediment.Dune migration rates are slower than previous regional estimates. Reasons for this are inconclusive and may be multifaceted. Possible reasons include inertial constraints, prolonged downcurrent reformation periods and longer dune relaxation associated with coarser grain sizes and a paucity of sediment on the outer shelf coupled with the Agulhas Current core migrating further in and offshore. This may explain the stability of the large barchan dunes and reduced movement of other sharp crested dunes relative to the regional migration rates.

Geophysical assessment of seawater intrusion: the Volturno Coastal Plain case study

In coastal alluvial plains, the variability of sedimentary inputs, tectonic and eustatism causes a complex subsurface geology which influences the position of fresh/saltwater interface. Furthermore, in these areas densely populated, the over-pumping of freshwater, coupled with the climate change events, promotes the landward migration of freshwater/saltwater boundary. This research illustrates the ability of geophysical tools to recognize the presence of salt/brackish water at Volturno Coastal Plain, Southern Italy. This area is characterized by a peculiar geological setting, due to the proximity at Somma–Vesuvio and Campi Flegrei volcanic areas, which profoundly influences the circulation of groundwater. The subsurface is mainly characterized by: (i) two denser layers located at − 10 m and − 20 m depth which in part prevents the vertical migration of groundwater, (ii) facies heteropy that facilitates the hydraulic connection between the different geological bodies, (iii) a discontinuous Campanian Ignimbrite deposits which favor the hydraulic connection between deeper and shallower aquifers. In this geological framework, 2D-ERT and 3D-ERT integrated with Downhole, Multichannel Analysis of Surface Waves and boreholes made possible to recognize the presence of two main zones with salt and brackish waters, respectively. The first zone, characterized by very low resistivity (≤ 1 Ωm) typical of salt water, stretches 1.5 km inland from the coast. The second zone, with a resistivity between 2 and 5 Ωm typical of brackish water, continues for other 3 km inland. This knowledge is useful for the engagement of all stakeholders (farmers, ranchers and policy makers) in the sustainable use of fresh water and for making water management plan operational tools.

Investigating Multilayer Aquifer Dynamics by Combining Geochemistry, Isotopes and Hydrogeological Context Analysis

Geochemical tracers have the potential to provide valuable insights for constructing conceptual models of groundwater flow, especially in complex geological contexts. Nevertheless, the reliability of tracer interpretation hinges on its integration into a robust geological framework. In our research, we concentrated on delineating the groundwater flow dynamics in the Innisfil Creek watershed, located in Ontario, Canada. We amalgamated extensive hydrogeological data derived from a comprehensive 3D geological model with the analysis of 61 groundwater samples, encompassing major ions, stable water isotopes, tritium, and radiocarbon. By seamlessly incorporating regional physiographic characteristics, flow pathways, and confinement attributes, we bolstered the efficiency of these tracers, resulting in several notable findings. Firstly, we identified prominent recharge and discharge zones within the watershed. Secondly, we observed the coexistence of relatively shallow and fast-flowing paths with deeper, slower-flowing channels, responsible for transporting groundwater from ancient glacial events. Thirdly, we determined that cation exchange stands as the predominant mechanism governing the geochemical evolution of contemporary water as it migrates toward confined aquifers situated at the base of the Quaternary sequence. Fourthly, we provided evidence of the mixing of modern, low-mineralized water originating from unconfined aquifer units with deep, highly mineralized water within soil–bedrock interface aquifers. These findings not only contribute significantly to the development a conceptual flow model for the sustainable management of groundwater in the Innisfil watershed, but also offer practical insights that hold relevance for analogous geological complexities encountered in other regions.

Serra Geral Group plumbing system and 3D geological framework in Morungava region, southern Paraná-Etendeka LIP (Brazil): Evidence from borehole, geochemical, and petrophysical data

The Morungava region (east of Porto Alegre-Rio Grande do Sul, Brazil), in the southern half of the Paraná-Etendeka Large Igneous Province (LIP), hosts Serra Geral Group subvolcanic intrusions (sill complex). These intrusions comprise various chemical compositions, including high-Mg rocks. So far, only a few examples of high-Mg rocks have been discovered in the Paraná-Etendeka LIP. Many investigations have been conducted in the Morungava region, yet several questions regarding the distribution, geometry, composition, and structural framework of the subvolcanic bodies in the subsurface remain unanswered. Therefore, we built a three-dimensional geological model of the Serra Geral Group sills and their associated stratigraphic framework in the Morungava region. This was achieved through the combined analysis of geological data (boreholes and geological maps), as well as petrophysical and chemical data, to improve the understanding of these subvolcanic bodies underground. The stratigraphic framework depicts the Precambrian basement topography, the distribution of the Paraná Basin units, and the Rio Grande do Sul Coastal Plain strata, which span the majority of the examined area. To categorize the Serra Geral Group rocks intersected by the boreholes, we established a validation and correlation technique using three separate data sources: laboratory geochemical data, portable X-ray fluorescence measurements, and gamma-ray logs. Using this technique, we classified the Serra Geral Group rocks in the Morungava region into three types (1, 2, 3), which share compositional similarities with Palmas, Vale do Sol, and Torres formations, respectively. Additionally, we identified a fourth type that could be compared to the Lomba Grande Complex, Silica Saturated Olivine Tholeiite-type dikes, and some high-Mg rocks from Namibia.

Mineralogy and Provenance of Iron Sand Deposits from Cipatujah and Cikalong, Tasikmalaya, West Java, Indonesia

Provenance, paleoweathering, and tectonic environment were studied on the iron sand samples taken from Cipatujah and Cikalong areas in Tasikmalaya, West Java, Indonesia using their mineralogical and geochemical data. These data were obtained from mineralogy grain analysis, X-ray fluorescence, dan ICP MS. From this study, iron sand deposits in both areas vary in grain sizes from very coarse to fine sand. Various minerals, such as magnetite, ilmenite, hematite, pyroxene, amphibole, garnet, quartz, ankerite, plagioclase, and zircon were identified. In addition, rock fragments, fossils, and clay are also found. In term of grain size, the placer deposit is geochemically classified as Fe shale (clay-silt grain size). The provenance shows that the basic rocks act as the source rock based on REE values, heavy mineral assemblage, and elemental ratios. Based on the provenance characteristics, regional geological framework, and catchment area pattern, the Jampang Formation and Young Formation of Mount Cikuray are the most possible sources of iron sand. The chemical index of alteration calculated from major oxide values indicates that the source area had intense chemical weathering. Heavy minerals contained in iron sand deposits reveal a low maturity based on compositional variability (16.58–36.55). Both iron sand deposits from Cipatujah and Cikalong originated in a continental arc setting, which coincides with the current tectonic setting of western Java.

Serra Geral Group plumbing system and 3D geological framework in Morungava region, southern Paraná–Etendeka LIP (Brazil): Combining 3D geologic and magnetic models

A coupled 3D geophysical–geological model was constructed by integrating aeromagnetic data and a prior 3D geological model of the Morungava region (Araújo et al., 2023 [manuscript submitted for publication]), situated at the southeastern border of the Paraná–Etendeka large igneous province (LIP) in Brazil. Aeromagnetic data interpretation and modeling (qualitative and semi-quantitative interpretation, susceptibility inversion, forward modeling, and magnetic vector inversion (MVI)), along with magnetic susceptibility data, complemented understanding of the Serra Geral Group feeder system in the subsurface (spatial distribution, depth, and geometry) and illuminated the crustal framework at different depths. We recognized three major NE-elongated geophysical domains (NW, Central, and SE), which were interpreted as basement compartments: the Tijucas, Pelotas, and Jaguarão terranes. The final integrated 3D geophysical–geological model encompasses the stratigraphic framework and the Serra Geral Group plumbing system in the study area, that comprises: two dike systems, four subvolcanic complexes with associated nested sills, and two intrusive ring complexes. This is the first time that these aeromagnetic data have been combined with borehole and 3D geological models.

Genesis and Evolution of the Yolindi Cu-Fe Skarn Deposit in the Biga Peninsula (NW Turkey): Insights from Genetic Relationships with Calc-Alkaline Magmatic Activity

The current work investigates the impact of magmatic fluids and metasomatic processes on the Yolindi Cu-Fe skarn deposit in the Biga Peninsula, Turkey. It traces the stages of skarn evolution, from prograde to retrograde alterations, and investigates findings within a broader geological, mineralogical, and geochemical framework. Additionally, it assesses the evolutionary history of the Yolindi deposit in relation to calc-alkaline magmatic activity in an island-arc environment and compares its mineral compositions and genesis with other global and regional Cu-Fe skarn deposits. The Yolindi Cu-Fe skarn deposit in the Biga Peninsula was formed by the intrusion of Şaroluk quartz monzonite pluton into Upper Paleozoic Torasan Formation rocks such as phyllite, schists, hornfels, marble, and serpentinites. During skarnification, reactions between the magmatic fluids from the Şaroluk quartz monzonite pluton and the Torasan Formation produced skarn minerals associated with metals such as Fe and Cu. Initially, these reactions formed prograde skarn minerals such as augite-rich pyroxenes and andradite garnets with magnetite and pyrite. As the system cooled, these initial minerals underwent retrograde alteration, leading to the formation of minerals such as epidote, actinolite, and chlorite, as well as other copper and iron minerals including chalcopyrite, bornite, secondary magnetite, and specular hematite. Therefore, four main stages influenced the formation of the Yolindi Cu-Fe deposit: metamorphic bimetasomatic, prograde metasomatic, and retrograde metasomatic stages. Later, oxidation and weathering resulted in supergene minerals such as cerussite, malachite, and goethite, which serve as examples of the post-metamorphic stage. The mineralogical shifts, such as the andradite–grossular transition, reflect changing hydrothermal fluid compositions and characteristics due to the addition of meteoric fluids. Importantly, the formation of magnetite after garnet and clinopyroxene during the retrograde stage is evidenced by magnetite crystals within garnet. The mineral associations of the Yolindi Cu-Fe skarn deposit align with the global skarn deposits and specific Turkish skarns (e.g., Ayazmant Fe-Cu and Evciler Cu-Au skarn deposits). The Yolindi Cu-Fe skarn deposit, in association with ore-bearing solutions having magmatic origins, developed in an island-arc setting.

Utilizing shallow seismic reflection for mitigating seismic and geo-environmental hazards in the development project of Gabal Ataqa Area, Cairo–Suez District, Egypt

Nowadays, development projects are becoming so rapid in many developing countries worldwide. The study of interest focuses on Cairo–Suez District, which represents the most important location in Egypt for major infrastructure projects and urbanization expansion. Consequently, it is very important to reduce the hazards surrounding this area from natural disasters, so all information that supports geo-environmental hazards assessment is importantly needed. The Gabal Ataqa area has socioeconomic importance as it is considered the industrial zone in the national project for developing the northern part of the Gulf of Suez. The situation of Gabal Ataqa area for being rich with numerous geological structures, and its socioeconomic importance calls the need for the delineation of the subsurface structural features in this area using the appropriate method. The geological framework has recognized all Quaternary faults in the Gabal Ataqa area as they are exposed to the surface, at the same time, no seismic reflection data has been acquired in the Gabal Ataqa area. Accordingly, the shallow seismic reflection method is applied in the Gabal Ataqa area to detect the Quaternary faults that are not exposed to the surface and also to detect any subsurface features that may cause construction problems, such as water-wet sands, sabkhas, and limestone cavities. Three lines of 2D seismic profiles are acquired in the study area. After applying seismic data processing and interpretation, two Quaternary faults have been recognized in the first and third lines. The location of the first seismic line has been chosen to be between two historic earthquake events, increasing the probability that the sources causing these two events will be located on the newly recognized quaternary fault. A dim spot has been recognized in the second seismic line at a depth of 50 m, which may indicate the presence of a groundwater aquifer or wet sandstone layer. Based on these results, changing the industrial zone place to another side to be away from the area of the three seismic lines is highly recommended.

Optimized event stratigraphy of Cenomanian-Turonian ostracods of North Africa and the Middle East

During the Cenomanian and Turonian, high eustatic sea levels combined with subsidence of North Africa resulted in widespread marine inundation and the evolution of an indigenous benthic fauna, including many endemic ostracod taxa. This is the first study to combine all information on the ranges of Cenomanian and Turonian ostracods and associated planktonic foraminifera across North Africa and the Middle East into a single event-stratigraphic composite scale. Information includes the ranges of the taxa in measured sections and wells in published articles and in unpublished theses and dissertations. Nine events are tracked across the region and are used to subdivide sections and wells into subsections whose boundaries separate older sections below from younger sections above. Pseudosections were coded to represent the older and younger surfaces of the events that are separated by a very thin interval. The subsections provide a geologic framework of ordered packages of sections and associated biologic events. In this methodology, the sequence stratigraphy is an integral part of the biostratigraphic analysis. This study includes 121 sections and wells that were subdivided into 218 sections and subsections, including the nine pseudosections, the first and last occurrences of 189 taxa, and 18 unpaired events, which resulted in a total of 396 events. This information was coded into software that uses a heuristic algorithm to optimize the sequence of events. The resulting composite was used to correlate the sections and subsections, produce range charts, and calculate diversity of ostracods. Computer runs were made for each of the four study areas (Morocco and western Algeria, eastern Algeria and Tunisia, Egypt, and the Southern Levant) separately and unitedly. Run separately, diversity peaks reflect biases of the local available information, but the combined results show steady rates of evolution and extinction that produced a peak in diversity of 66 species in the late Cenomanian. There are no mass extinction events. The continued faunal turnover also indicates that there is no community stasis in the Cenomanian-Turonian ostracods of the region.

Reconnaissance Basement Geology and Tectonics of North Zealandia

AbstractNew rock dredge samples supply key information to establish the tectonic and geological framework of the northern two‐thirds of the 95% submerged Zealandia continent. The R/V Investigator voyage IN2016T01 to the Fairway Ridge, Coral Sea, obtained poorly sorted poly‐lithologic pebbly to cobbly sandstones, well sorted fine grained sandstones, mudstones, bioclastic limestones, and basaltic lavas. Post‐cruise analytical work comprised petrography, whole rock geochemical and Sr and Nd isotopic analyses, and U‐Pb zircon, Rb‐Sr, and Ar‐Ar geochronology. A Fairway Ridge cobbly sandstone has a ∼95 Ma (early Late Cretaceous) depositional age; two biotite granite cobbles are 111 ± 1 and 128 ± 1 Ma in age, and some volcanic pebbles are also likely Early Cretaceous. Fairway Ridge basalts have intraplate alkaline chemistry and are of Late Eocene age (∼40–36 Ma). By analogy with South Zealandia, we interpret strong positive continental magnetic anomalies of North Zealandia to mainly result from Late Cretaceous to Cenozoic intraplate basalts, many of them rift‐related lavas. A new basement geological map of North Zealandia shows the position of the Mesozoic Gondwana magmatic arc axis (Median Batholith) and other major geological units. This study completes onland and offshore reconnaissance geological mapping of the entire 5 Mkm2 Zealandia continent.

Development of Integrated Fuzzy Model for Mine Management Optimization

Technoeconomic, environmental and safety criteria generally affect the management of metallic and non-metallic mining operations. The first basic question that needs to be addressed when planning ore mining is which methods are adequate and what is the optimal mining technology? Due to the complex geologic framework of ore deposits, geological exploration has rendered synonymous the inherent uncertainties, vagueness, and inaccuracies. As a result, subjective evaluation by engineers and expert experience have become increasingly important. Given that the natural language used by miners and geologists is most suited for relaying knowledge and expressing opinions, the paper tests a fuzzy optimization methodology that uses linguistic variables. Consequently, extent analysis is applied to fuzzy AHP by means of triangular fuzzy numbers to arrive at a decision about the optimal mining technology. The entire procedure constitutes an integrated mine management system, which will contribute to sustainable production in the future. A case study to which the model was applied is presented in the paper.