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Core drilling has been used successfully in archaeology for a variety of applications, including mapping stratigraphy across large areas, estimating feature depth and content, understanding site formation processes, as well as complementing information obtained through surface collection and geophysical survey. In this paper, we provide an overview of the first core drilling campaign carried out in 2021 on the outer settlement of the Bronze Age tell from Toboliu in western Romania. The overall aim of this coring program was to gather information regarding the nature of various features within the settlement, with a focus on the anomalies visible in the geomagnetic site plan. Based on 165 drilled cores, a reconstruction of the site's stratigraphy is presented in this paper. This reconstruction was controlled and confirmed by excavations in one of the coring transects where the stratigraphic interpretation of the cores could be linked with the excavated stratigraphy. Additionally, samples for radiocarbon dating were collected from several cores. Based on this data, we discuss preliminary insights into possible house locations and preservation issues, as well as the chronological development and occupation sequence of this complex site. [ABSTRACT FROM AUTHOR]

Hyperspectral imaging is gaining widespread use in the resource sector, with applications in mineral exploration, geometallurgy and mine mapping. However, the sheer size of many hyperspectral datasets (>1 Tb) and associated correction, visualisation and analysis challenges can limit the integration of this technique into time-critical exploration and mining workflows. In this contribution, we propose and demonstrate a novel open-source workflow for rapidly processing hyperspectral data acquired on exploration drillcores. The resulting products are adaptable to the varied needs of geologists, geophysicists and geological engineers, facilitating better integration of hyperspectral data during decision making. These tools are applied to process hyperspectral data of 6.4 km of exploration drill cores from Stonepark (Ireland), Collinstown (Ireland) and Spremberg (Germany). The results are presented via an open-source web-viewing platform that we have developed to facilitate easy on and off-site access to hyperspectral data and its derivatives. We suggest that maximum value can be extracted from hyperspectral data if it is acquired shortly after drilling and processed on-site in real time, so that results can be quickly validated and used to inform time-critical decisions on sample selection, geological interpretation (logging) and drillhole continuation or termination. This timeliness and accessibility is key to ensure rapid data availability for decision makers during mineral exploration and exploitation. Finally, we discuss several remaining challenges that limit the real-time integration of hyperspectral drill core scanning data, and explore some opportunities that may arise as these rich datasets become more widely collected. [ABSTRACT FROM AUTHOR]

Natural hydrogen (H 2) emanations in intracratonic areas offer potentially exploitable carbon-free energy. To date, H 2 seepages have been detected in more than sixty sites with exploration ongoing in many locations. One mechanism of natural hydrogen generation is the oxidation of Fe2+ in Fe-rich lithologies, and estimating the potential for hydrogen generation by this pathway is an important aspect of characterizing H 2 -generating rocks. However, accurate estimation of Fe2+ can be challenging due to large-scale heterogeneities and small sample sizes used in conventional analysis. Here, we propose a correlative imaging technique to assess H 2 generation potential in Fe2+-rich source rocks by integrating 2D chemical information with 3D volumes of the rock imaged using X-ray computed tomography (micro-CT). The advantage of this method lies in its ability to analyze a whole drill core of the source rock to obtain the most representative values while preserving sample integrity. Our method, validated on fractured monzo-diorite from a natural H 2 -emitting well in Kansas, USA, yields an estimate of 707.93 ± 49.18 mol (H 2)/ton (source rock), as the upper limit. The proposed method could be useful in characterizing source rocks and estimating their natural H 2 generation potential in the early stages of natural H 2 exploration. • We propose a method to quantify Fe2+ in a H 2 source rock by an imaging technique. • Upper limit of H 2 generation in mols (H 2)/ton (rock) was obtained assuming that all Fe2+ reacted to generate H 2. • Method allows imaging large representative samples such as drill cores (1 m). • Ensures minimal sample destruction and high accuracy. [ABSTRACT FROM AUTHOR]

Traditional drilling methods often face difficulty meeting the demand for efficient and accurate coring under complex geological conditions. Cordless coring is an advanced technology that uses hydraulic lifting to carry out coring, which can achieve automation and automated and intelligent drilling operations. In this research, a new type of hydraulic lifting cordless coring drilling tool is designed. Moreover, a numerical simulation model of the fluid flow in the annulus between the spearhead and spool of the cordless coring drilling tool was established. Orthogonal simulation tests are carried out, and according to the orthogonal test data, a numerical prediction model of the spool annulus fluid field based on the Backpropagation Neural Network (BP neural network) is established. The prediction of the flow rate of the drilling fluid and the spool back-pressure ratio was obtained when the structural parameters of the spearhead and the spool annulus were different. A multi-objective optimization of the annulus flow structure of the cordless core drilling tool has been carried out. The optimization objectives include deciding the back pressure ratio of the spool overcoming the spring and the flow rate of the drilling fluid. According to the established nonlinear optimization model and based on the improved Non-dominated Sorting Genetic Algorithm II (NSGA-II) multi-objective optimization algorithm, it is verified that the convergence speed and diversity of the improved algorithm are better than those before the improvement. The simulation and experimental validation are carried out. It is verified that the flow rate of drilling fluid increased by 33.56% after optimization, and the force ratio was lowered by 5.825%. Finally, based on the simulation and optimization results, the φ96 cordless core drilling tool was manufactured on a trial basis, and on-site concrete drilling, coring, and hydraulic lifting operations were conducted for smooth coring and lifting. This study could provide an important scientific basis and technical support for the application and development of hydraulic lifting cordless coring technology. [ABSTRACT FROM AUTHOR]

Residual stresses refer to those stresses from sources other than contemporary tectonic forces that are locked within the rock formation. These stresses could develop and be stored within the rock during the cooling process of rock formation, metamorphism periods, previous tectonic activities, and other deformation phenomena. If relieved, by any excavation activity, for example, they can cause immediate or time-dependent (or both) deformations due to strain relaxation. If such stresses existed in any high-strength unfractured rock formations (such as a metamorphosed iron formation) in the path of an exploration core drilling, these strain relaxations could be large enough to break up the core into small pieces, reducing the rock quality designation (RQD) values even down to zero. If these stresses exist and are ignored, the RQDs from the coring could be very misguiding which results in over-designing and unnecessarily increased time and expenses of projects. In this paper, a numerical modeling approach was used to investigate a case study where an RQD of zero was reported for a shallow high-strength unfractured rock formation in Michigan. As the geologic data indicate this formation is not fractured at all, the zero value of RQD could be the result of core damage during drilling. The results of the numerical modeling conducted in this study confirmed that the release of locked-in residual stresses during the drilling process could explain the observed core damage and observed zero value for the RQD. [ABSTRACT FROM AUTHOR]

This paper details the utilization of the focused ion beam digital image correlation (FIB-DIC) technique for measuring in-plane displacements and the employment of the height digital image correlation (hDIC) technique as a two-step DIC method for determining displacements without an out-of-plane component within the region of interest. Consideration is given to the microscopy data's measurement scale and resolution to confirm the capability of both techniques to conduct micro-scale correlations with nano-scale sensitivity, making them suitable for investigating the residual elastic strains formed due to processing. The sequential correlation procedure of the FIB-DIC technique has been optimized to balance accuracy and performance for correlating sequential scanning electron microscope (SEM) images. Conversely, the hDIC technique prioritizes the accurate correlation of SEM images directly with the reference state without a sequential procedure, offering optimal computational performance through advanced parallel computing tools, particularly suited for correlating profilometry data related to large-scale displacements. In this study, the algorithm of the hDIC technique is applied as a two-step DIC to evaluate the elastic strain relaxation on the surface of a ring core drilled using a focused ion beam. Both techniques are utilized to correlate the same SEM images collected during the monitoring of the ring drilling process. A comparison of the correlation results of both techniques is undertaken to quantify the near-surface residual elastic strains, with an analysis conducted to discern the accuracy of the hDIC algorithm. Furthermore, the distinctions between the two techniques are delineated and discussed. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Geology & Oilfield Development in Daqing is the property of Editorial Department of Petroleum Geology & Oilfield Development in Daqing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Natural gas hydrate is widely distributed, shallow-buried, clean, and pollution-free and has enormous reserves, it is regarded as the alternative clean energy source in the oil and gas field with the most potential. Pressure coring is the only way to drill for gas hydrate core on the surface under in situ conditions, which is of great value for analyzing its occurrence conditions and reserves comprehensively. Based on this, a new wireline pressure coring system (WPCS) with a ball valve seal was designed and developed in this paper; it was applied in the deep sea for the first time in the South China Sea hydrate survey voyage of the Guangzhou Marine Geological Survey (GMGS). A total of 15 runs of deep-sea gas hydrate drilling and coring applications were carried out, and they tested well. The experimental water depth was 1700–1800 m, and the coring depth below the seafloor was about 100–150 m. The formation consisted of sandy hydrate and argillaceous hydrate. The results showed the following. (1) The success rate of ball valve turn-over could reach almost 100% in the argillaceous hydrate reservoir, although there are some isolated cases of pressure relief. Meanwhile, drilling in the sandy hydrate reservoir, the success rate was only 54.55%. (2) When drilling in the argillaceous hydrate reservoir, the core recovery rate could reach 80%, while in the sandy hydrate reservoir, it was almost 0%. In practice, the sandy formation with gas hydrate is stiff to drill compared to the performance in argillaceous formations. After our analysis, it was believed that the ball valve and core tube could be easily plugged by sand debris during the sampling of sandy hydrate formation. Moreover, the sandy core is easily plugged into the core liner because of the high friction of sand grains in clearance. (3) The pressure-holding effect of the core drilling tool was related to the formation of hydrate, the sealing form of the ball valve, and the environmental pressure. Sandy hydrate formations often caused the ball valve to jam, while the muddy hydrate formation did not. The research results of this paper have reference value for the further optimization of the WPCS structure, the optimization of drilling parameters, and the design parameters of the ball valve structure, which could be better used for the pressure coring of gas hydrate and subsequent research work in the future. [ABSTRACT FROM AUTHOR]

The discovery of the Northern Copper Belt in SW Poland is a result of an extensive exploration project with a key role played by various science-related methods. The project relied on mapping the distribution of mineral zones in the entire Fore-Sudetic Monocline, a unit known for its occurrences of Cu-Ag orebodies. This approach involved the examination of historical drill cores from over 400 oil and gas holes in this area, with the collection of samples for laboratory analyses. A close relationship was confirmed between the distribution of orebodies and the transformation of organic matter. Rock-Eval pyrolysis was also performed on selected samples. The tests of rock specimens were accompanied by the reprocessing of historical gravimetric and seismic surveying results. Field magnetotelluric surveying was also performed in certain areas. This phase resulted in the identification of areas with a high probability of finding the best ore, allowing for the initiation of the drilling stage. So far, 37 exploratory boreholes have been drilled in those locations, nearly all of them with highly positive results. The Northern Copper Belt consists of three deposits, Nowa Sól, Mozów, and Sulmierzyce North, along with numerous prognostic areas distributed therebetween. The future production of copper, silver, and the accompanying valuable elements presents a chance to provide the whole of Europe with a new plentiful supply of those critical raw materials. [ABSTRACT FROM AUTHOR]

Due to the frequent occurrence of defects of slope protection facilities on existing lines causing the potential major geological hazards (e.g., landslides), it is necessary to promote the inspection and detection efficiency of various defects of slope protection facilities for carrying out early warning and evaluation, as well as, putting forward relevant control measures for slope disasters. Based on the case studies of hundreds of protective facilities on the existing railway line, the typical defect types, characteristics and specific causes of retaining wall, slope protection, anti-slide pile and anchorage engineering structure are firstly determined. Subsequently, a new comprehensive method combining unmanned air vehicle (UAV) and intelligent detection of portable radar (IDPR) are proposed. Among of them, UAV can effective and efficient identify the defect situations of slope protection facilities, and the water accumulation and cracks of retaining wall through performing a periodic inspection of the surrounding environment of protective facilities. In addition, IDPR can detect the filling situations behind the protective facilities to prevent the collapse danger. Through comparison with the drilling core results of tested areas, it is found that the detection results of the IDPR are more reliable and accurate, which is worthy of popularization and application in the field. [ABSTRACT FROM AUTHOR]

Scientific drilling in polar regions plays a crucial role in obtaining ice cores and using them to understand climate change and to study the dynamics of polar ice sheets and their impact on global environmental changes (sea level, ocean current cycle, atmospheric circulation, etc.). Mechanical rotary cutting is a widely used drilling method that drives the cutter to rotate to cut and drill through ice layers. It is necessary to conduct in-depth research on the brittle fracture behavior of ice and mechanical model and to analyze the factors and specific mechanisms (cutter's angle, rotation speed of the drill bit, and cutting depth) affecting cutting force for the rational design of ice core drill systems, improving the efficiency of ice core drilling and ensuring the drilling process runs smoothly. Therefore, in this paper, the process of ice cutting was observed, the fracture mechanics characteristics of the ice cutting process were analyzed, the formation process of ice chips was divided into three stages, and a mathematical model for the cutting force was established based on the observation results. The paper describes the damage conditions of ice failure and points out the factors and specific laws influencing cutting force. Furthermore, the cutting force generated under various experimental conditions was tested. Based on specified real-time variation curves of cutting force, the characteristics of cutting force were analyzed during the cutting and drilling process. Based on comparison to results of the average cutting force, the influence mechanism of various parameters acting on the cutting force was obtained. This proves the correctness of the mathematical model of the cutting force and provides a theoretical reference for the calculation of the cutting force during ice cutting and drilling in polar regions. [ABSTRACT FROM AUTHOR]

Wetumpka impact structure is a Late Cretaceous, marine‐target impact crater of about 5 km diameter. The apparent crater rim is mostly made of crystalline local basement, and the apparent crater floor consists of a mixed sediments of target lithology. These sediments are the provenance of the crater‐filling impactite sands, overlying trans‐crater slide unit, and the capping polymict impact breccia deposit, often referred to by previous workers as "central polymict breccia." The unit has been known to contain elongated mega‐clasts of up to tens of meters in size. This study attempted to understand the mode of emplacement of this polymict breccia, which occurs in some places on the apparent crater floor and resembles a polymict proximal ejecta deposit. This work also reports the first documentation of rare, potential impact spherules in the polymict impact breccia, interpreted to be a part of distal ejecta. The presence of large, decimeter‐sized clasts in the breccia can be best explained by the movement of overturned rim flap forming part of proximal ejecta from the crater rim to the apparent crater floor during early modification stage of impact cratering. Our work highlights the bimodal clast size distribution of the polymict breccia, and so we propose that the term "mega‐clast‐bearing impact breccia" be used for this unit. We attribute a generally steep orientation of the decameter sized clasts to primary imbrication during emplacement. The emplacement of this breccia is interpreted as associated with the ejecta emplacement process that occurred before the return of marine resurge. [ABSTRACT FROM AUTHOR]

Glass-fiber-reinforced polymers' (GFRP), as compared to metallic materials, require more intricate machining. The composite construction experiences delamination as a result of this machining operation. Delamination at the exit and entrance of holes drilled is a significant flaw in composite materials. Superior-drilled holes can be produced by optimizing the drilling process's governing factors. This study's goal is to maximize the drilling settings using entropy weight-coupled gray relational analysis with fuzzy logic to account for multiple performance factors. Taguchi's L25 5-level orthogonal array is used to increase the accuracy of the results in this study. Feed rate and spindle speed are considered the control variables, and torque, thrust force, and delamination at both the exit and entry are the responses. The results show that drilling performance is enhanced by lower feed rates and elevated spindle speeds. Additionally, the present findings show that feed rate has a stronger influence on drilling hole quality. These results also proved that increasing the number of levels increases the accuracy of the results. Entropy-based gray relational analysis with fuzzy logic using more levels of factors can be effectively used for the optimization of the drilling process. [ABSTRACT FROM AUTHOR]

Changes in the function of a building will affect the structural loading, which, based on government regulations in building permits, must be reviewed for the feasibility of building functions through structural assessment. This research aims to analyze the condition of the concrete quality of building beams, columns, and slabs that are more than 50 years old. The methods used include non-destructive testing (NDT) and destructive testing (DT) on the structures. From the results of the non-destructive UPV (Ultrasonic Pulse Velocity) Test on 20 elements (100 tests) using the PUNDIT tool, the average concrete quality based on BS 1881 and ASTM C597-16 standards was found to be 28.15 MPa for columns, 25.11 MPa for beams, and 25.60 MPa for slabs. The Hammer Test showed an average concrete quality of 27.95 MPa for columns, 31.41 MPa for beams, and 31.20 MPa for slabs. The destructive method using core drilling on 8 structural elements revealed an average concrete quality of 25.58 MPa for columns, 34.61 MPa for beams, and 35.89 MPa for slabs. The hardness test for reinforcing steel indicated an average yield strength of 361 MPa. The compressive strength results of the column structure concrete meet the minimum requirements of 21 MPa for special structure concrete quality based on SNI-2847-2019. It is recommended to recalculate the structure with concrete quality fc' 25 MPa and steel quality fy 360 MPa to identify elements that need structural strengthening. [ABSTRACT FROM AUTHOR]

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To address the problems of wall collapse, cuttings slurrying, and scaling on the inner wall of the drill pipe, which often occur in small-diameter diamond wireline core drilling, the inhibition properties of polyvinyl alcohol (PVA) was investigated, and the formulation of solids-free drilling fluid with PVA as the inhibitor were completed. PVA has the advantages of fast adsorption and easy regulation of rheological properties Firstly the inhibition effect of PVA was compared with that of common inorganic salts (sodium chloride, NaCl, potassium chloride, KCl) by bentonite dispersion test, linear swelling test, shale rolling recovery test and mud ball immersion test in this study. Then, the inhibition mechanism of PVA was analyzed with potentiometric particle size tests, Fourier transform infrared (FT-IR) and X-ray Diffraction (XRD) measurements. Based on the outstanding inhibition performance of PVA, tackifiers and filtration reducers were preferred through the compatibility test. And finally, the effects of various contaminants on the comprehensive performance of the formulated solids-free drilling fluids were evaluated. The results showed that PVA exhibited better inhibition of clay hydration and dispersion in shale recovery and linear swelling compared to NaCl and KCl, which was particularly evident in the mud ball immersion test. FT-IR and XRD tests revealed that the inorganic salts were used to replace the cations with larger radius and high degree of hydration in the clay layer by ion exchange ti achieve the effect of clay de-watering by reducing the spacing of the clay interlayer and the electrostatic repulsion between the particles. However, PVA is strongly adsorbed on the clay surface in the form of hydrogen bonds due to its unique multi-hydroxyl chain structure, forming a hydrophobic barrier to prevent water molecules from entering the clay layer, thus inhibiting the hydration and swelling of the clay. Using PVA as an inhibitor, compounded with xanthan gum, sulfonated lignite resin and sulfonated gilsonite (FT-1), the solids-free drilling fluid is promising for use in diamond wireline core drilling in complex formations. [ABSTRACT FROM AUTHOR]

Copyright of Retos: Nuevas Perspectivas de Educación Física, Deporte y Recreación is the property of Federacion Espanola de Asociaciones de Docentes de Educacion Fisica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A deep geological facility (Cigéo project) is planned, if authorized, in the Callovo-Oxfordian claystone (COx) for the disposal of all long-lived radioactive waste produced in France. The heat emitted from the most exothermic wastes, emplaced in horizontal parallel micro-tunnels, will lead to a temperature increment within the COx. The resulting thermal pressurization may lead to tensile effective stresses and induce thermal hydrofracturing. One of the design criteria for this area is to avoid any damage induced by thermal loading, especially in the far field. The French National Radioactive Waste Management Agency (Andra) has conducted an in situ heater experiment at the Meuse/Haute-Marne Underground Research Laboratory to better understand the thermal hydrofracturing process of the COx. The experiment's design was conceived in a way that the thermal pressurization will be sufficiently high to generate effective tensile stresses larger than the effective tensile strength of the COx. To induce thermal hydrofracturing, the COx was submitted to temperatures and pore pressures higher than those expected in the Cigéo project. A breakdown pore pressure, a sign of a fracture event, was registered by the measurements during the second heating cycle. These observations were also confirmed by the post-test core drilling. Furthermore, the numerical modelling of the experiment shows that the thermo-poro-elastic approach reproduces the temperature and pore pressure measurements well in a wide range of locations up to just before the occurrence of the fracture event. This satisfactory reproduction provides confidence for the design of the Cigéo project. Highlights: An in situ experiment was performed in the Meuse/Haute-Marne Underground Research Laboratory to study the thermal hydrofracturing of the Callovo-Oxfordian claystone. The heating strategy consisted of applying a thermal load to reach the tensile strength and to fracture the rock. The measurements, the numerical modelling, and the post-test core drilling indicate a fracture was created after two heating phases. The thermal pressurization induced a hydraulic fracture during the second phase after 28 days of heating. The thermo-poro-elastic approach reproduces well the measurements in a large range of the measurement locations. [ABSTRACT FROM AUTHOR]

The article discusses the use of tritium (3 H) and cesium (137 Cs) as temporal markers in ice cores extracted from temperate glaciers. We present a complete tritium profile for a 46 m ice core drilled from the Adamello Glacier, a temperate glacier in the Italian Alps, and compare it to the 137 Cs profile from the same ice core. Our analysis reveals tritium contamination between 19 and 32 m of depth, which can be attributed to the global radioactive fallout caused by atmospheric nuclear-bomb testing that took place in the 1950s and 1960s. Results show that the radioactive peak associated with 1963 does not occur at the same depth for both 3 H and 137 Cs; instead, the tritium peak is 1.5 m above the cesium one. Our hypothesis is that this misalignment is caused by meltwater-induced post-depositional processes that affect 137 Cs, which is more sensitive to percolation than 3 H. The total inventory of 137 Cs in this ice core is also among the lowest ever reported, providing additional evidence that the presence of meltwater has affected the distribution of this radionuclide within the ice. In contrast, the total tritium inventory is comparable to what is reported in the literature, making it a more reliable temporal marker for temperate glaciers. [ABSTRACT FROM AUTHOR]

The Ordovician thick dolostone in Shuntogol area of the Tarim Basin has the potential to form a large-scale reservoir, but its genesis and reservoir development model are still unclear. Starting from a sedimentary sequence, this study takes a batch of dolostone samples obtained from new drilling cores in recent years as the research object. On the basis of core observation and thin section identification, trace elements, cathodoluminescence, carbon and oxygen isotopes, rare earth elements, and X-ray diffraction order degree tests were carried out to discuss the origin of the dolomite and summarize the development model of the dolostone reservoir. The analysis results show that the Ordovician dolomite in the study area had a good crystalline shape, large thickness, high Fe and Mn values, and mostly showed bright red light or bright orange–red light under cathode rays. The ratio of δ18O values to seawater values at the same time showed a negative bias; the δCe values were negative anomalies, the δEu values were positive anomalies, and the order degree was high. This indicates that the dolomitization process occurred in a relatively closed diagenetic environment. The Ordovician carbonate rocks in the study area were low-lying during the sedimentary period, and with the rise of sea level, the open platform facies continued to develop. When the Middle and Lower Ordovician series entered the burial stage, the main hydrocarbon source rocks of the lower Cambrian Series entered the oil generation peak, and the resulting formation overpressure provided the dynamic source for the upward migration of the lower magnesium-rich fluid, and the dolomitization fluid entered the karst pore system in the target layer to produce all the dolomitization. This set of dolostone reservoirs is large in scale and can be used as a favorable substitute area for deep carbonate exploration for continuous study. [ABSTRACT FROM AUTHOR]

This study aims to correlate the mechanical properties measured in the laboratory and the field for weak and crushable limestone in a mining site containing random karstic cavities. Compressive tests were performed in the laboratory to obtain Unconfined Compressive Strength (UCS) and rock mass modulus (Erm). Field tests were: i) boring and drilling cores that allowed obtaining Rock Quantification Distribution (RQD) and recovery rock parameter (REC), and ii) Ground Penetration Radar (GPR) to detect and locate random cavities in the underground limestone deposit. The correlation between the Em/UCS rate and the RQD was determined and analyzed. Based on the role of the new interpretation of the Geological Strength Index (GSI) and its relationship with the Erm/UCS rate, a mathematical relationship was determined to link GSI and RQD. This relationship was a basis for modifying the generalized Hoek-Brown criterion, involving the amplitude of reflected electromagnetic waves (EM) provided by GPR field tests. [ABSTRACT FROM AUTHOR]

Drilling is one of the most commonly used techniques in hydrogeological exploration and is employed to obtain rock samples and create boreholes. During conventional drilling, it is necessary to raise all the drilling tools in the borehole when switching between coring drilling and non-coring drilling, which causes large auxiliary operation time consumption and poor drilling efficiency. Based on the structure of wireline coring tools, a large diameter modular drill bit was designed to switch between coring drilling and non-coring drilling without lifting the whole set of drilling tools. In the COMSOL simulation environment, a simulation model of the modular bit was constructed. Drilling fluid velocity and pressure characteristics flowing through the modular bit were studied. According to the analysis results, with the same input flow rate, similar velocities and lower pressure loss can be obtained in non-coring drilling as with the coring bit, and thus drilling cuttings can be removed effectively even if there are more cuttings produced in non-coring drilling than in coring drilling for a borehole drilled at the same diameter. When the outside diameter of the modular bit is 216 mm, the recommended clearance value is 9 mm or 10 mm in order to obtain lower pressure loss and larger diameter core. To generate low pressure loss and ensure bit strength, a layout with four nozzles on the internal non-coring bit is recommended. The modular bit enables fast switching between coring drilling and non-coring drilling without raising the drilling tools. The simulation model can be used for drilling parameter selection and drill bit optimization. [ABSTRACT FROM AUTHOR]

Understanding the behavior of mercury (Hg) in organic‐rich sediments as they undergo thermal maturation is important, for example, because enrichment of Hg in sedimentary deposits has become a widely used proxy for volcanism from Large Igneous Provinces (LIPs). In this study, we evaluate the effects of such processes on sedimentary Hg concentrations by investigating a common stratigraphic interval in three drill cores with different levels of thermal maturity (immature, mature and post‐mature) in Toarcian sediments (Posidonienschiefer Formation) from the Lower Saxony Basin, Germany. We present Hg concentrations, bulk organic geochemistry, and total sulfur data. Mercury concentrations in the mature and post‐mature sediments are increased >2‐fold relative to the immature material, which is greater than any potential differences in original Hg concentrations in the studied successions prior to burial. Organic‐carbon and host‐rock mass loss during thermal maturation may have concentrated Hg in the mature sediments to some extent, provided Hg is considered effectively immobile. The increased Hg, TOC‐normalized Hg, and TS‐normalized Hg are most likely linked to the "closed system" behavior of Hg in sedimentary basins and the relatively low temperatures (70–260°C) during maturation that resulted in limited Hg mobility. More speculatively, a certain degree of redistribution of Hg within the mature sediments is suggested by its enrichment in distinct stratigraphic levels. Regardless of the exact mechanisms at play, the elevated Hg concentrations in mature sediments amplify both Hg/TOC and Hg/TS, implying that thermal effects must be considered when using normalized Hg as a proxy for far‐field volcanic activity. Plain Language Summary: This study examines how mercury (Hg) behaves in organic‐rich sediments that undergo thermal maturation, which is crucial for using Hg concentrations as a proxy for paleo‐volcanic activity. We analyzed three drill cores from the Lower Saxony Basin in Germany, each representing different stages of thermal maturity (immature, mature, and post‐mature). We measured Hg concentrations, organic content, and sulfur levels in these sediments. We found that mature and post‐mature sediments show more than double the Hg concentrations compared to immature sediments. This increase is likely due to the loss of organic matter and rock mass during maturation, which concentrates the remaining Hg. The relatively low temperatures (70–260°C) during maturation kept Hg from moving significantly, resulting in higher concentrations in mature sediments. There might be some redistribution of Hg within mature sediments, seen as enrichment in certain layers. Overall, the study highlights that thermal maturation effects must be accounted for when using Hg as a proxy for paleo‐volcanic activity. Key Points: Hg concentrations in thermally matured organic‐rich deposits have increased >2‐foldHg mobilization and recapture may occur during thermal maturation, and may result in stratigraphic increases in Hg concentrationsThe thermal history of sediments must be considered when using Hg as a proxy for volcanism [ABSTRACT FROM AUTHOR]

Volcanic flank collapses, especially those in island settings, have generated some of the most voluminous mass transport deposits on Earth and can trigger devastating tsunamis. Reliable tsunami hazard assessments for flank collapse‐driven tsunamis require an understanding of the complex emplacement processes involved. The seafloor sequence southeast of Montserrat (Lesser Antilles) is a key site for the study of volcanic flank collapse emplacement processes that span subaerial to submarine environments. Here, we present new 2D and 3D seismic data as well as MeBo drill core data from one of the most extensive mass transport deposits offshore Montserrat, which exemplifies multi‐phase landslide deposition from volcanic islands. The deposits reveal emplacement in multiple stages including two blocky volcanic debris avalanches, secondary seafloor failure and a late‐stage erosive density current that carved channel‐like incisions into the hummocky surface of the deposit about 15 km from the source region. The highly erosive density current potentially originated from downslope‐acceleration of fine‐grained material that was suspended in the water column earlier during the slide. Late‐stage erosive turbidity currents may be a more common process following volcanic sector collapse than has been previously recognized, exerting a potentially important control on the observed deposit morphology as well as on the runout and the overall shape of the deposit. Plain Language Summary: Disintegration of volcanic islands can cause very large landslides and destructive tsunamis. To assess the tsunami hazard of such events, it is crucial to understand the processes that are involved in their formation. We present new insights from seismic data and drill cores from a landslide deposit offshore Montserrat, a volcanic island in the Lesser Antilles Arc in the Caribbean. Our analysis reveals the emplacement of landslide material in several stages, including multiple volcanic flank collapses, incorporation of seafloor sediments and an erosive flow that carved channels into the top of the deposit right after its emplacement. We suggest that highly erosive flows are a common process during volcanic flank collapse deposition and that they play a significant role in the shaping of the deposit's appearance. Key Points: Landslide emplacement offshore Montserrat included volcanic flank collapses, sediment incorporation, and a late‐stage erosive flowHighly erosive flows are likely to be common processes during volcanic flank collapse depositionPre‐existing topography plays a major role in shaping flank collapse‐associated mass transport deposits [ABSTRACT FROM AUTHOR]

Knowledge regarding the abundance and distribution of solar wind (SW)‐sourced water (OH/H2O) on the Moon in the shallow subsurface remains limited. Here, we report the NanoSIMS measurements of H abundances and D/H ratios on soil grains from three deepest sections of the Chang'E‐5 drill core sampled at depths of 0.45–0.8 m. High water contents of 0.13–1.3 wt.% are present on approximately half of the grain surfaces (topmost ∼100 nm), comparable to the values of Chang'E‐5 scooped soils. The extremely low δD values (as low as −995‰) and negative correlations between δD and water contents indicate that SW implantation is an important source of water beneath the lunar surface. The results are indicative of homogeneous distribution of SW‐derived water in the vertical direction, providing compelling evidence for the well‐mixed nature of the lunar regolith. Moreover, the findings demonstrate that the shallow subsurface regolith of the Moon contains a considerable amount of water. Plain Language Summary: Recently, China's Chang'E‐5 mission targeted a higher latitude on the Moon than previous Apollo and Luna missions, and brought back scooped and drilled samples to the Earth. These new soil samples provide an opportunity to investigate the distribution, abundance, and origin(s) of water in Moon's middle latitude. Here, we focus on using the NanoSIMS technique to analyze water content on soil near‐surface regions to understand whether the solar wind (SW)‐derived water could be preserved after burial at depth. Our results show that more than half of the core soils have high water contents on the rims of grains, similar to those of the Chang'E‐5 scooped soils. This finding suggests that the SW remains an important source of water in the Moon's subsurface. Our work provides direct evidence that the lunar regolith below the surface contains considerable water from SW implantation. This type of water could be a promising water resource in future exploration. Key Points: More than half of the soils from the single drill core have high water contents and low D/H ratios below the surfaceThe solar wind (SW)‐derived water could be preserved for hundreds of millions of years if buried at depthLunar regolith from the drill core contains considerable water from SW implantation, which is much more accessible [ABSTRACT FROM AUTHOR]

The Moon's mare volcanism predominantly occurs within the Procellarum KREEP Terrane (PKT), which is widely thought to be associated with KREEP components within the lunar interior. The Chang'e-5 (CE-5) mission sampled a young (2 Ga) mare basalt Em4/P58 unit of northern Oceanus Procellarum. The geochemistry of the CE-5 mare basalt enables assessment of mantle source compositions which are essential to understand the thermo-chemical mechanism for prolonged volcanism during secular cooling of the Moon. Geochemical compositions of the CE-5 bulk soil, breccias, and basalt clasts from various depths within the drill core consistently display high concentrations of incompatible trace elements (ITE: ∼ 0.3 × high-K KREEP; ∼ 5 μg/g Th) with KREEP-like inter-element ratios, for example for La/Sm, Nb/Ta, and Zr/Y. Exotic impact ejecta, extensive magma differentiation (<70 % fractional crystallization) and significant assimilation of KREEP materials during magma transit and eruption cannot account for the ITE contents and ratios or radiogenic isotope compositions (e.g., εNd initial of + 8 to + 9 and εHf initial of + 40 to + 46) of the CE-5 basalts; instead, partial melting of their mantle source played a dominant role. The Chang'e-5 basalt is a chemically evolved low-Ti mare basalt (Mg# of ∼ 34) with enriched KREEP-like ITE compositions but high long-term time-integrated Sm/Nd and Lu/Hf ratios, which represent a hitherto unsampled type of mare basalt. It formed by melting of an augite-rich mantle source (late-stage magma ocean cumulates containing > 30–60 % augite, and little or no ilmenite), with a small amount of late-stage interstitial melt that resembles KREEP (∼1–1.5 modal %, equivalent to 0.2–0.3 μg/g Th in the mantle source). The voluminous mare basalts making up the Em4/P58 unit (>1500 km3) provide compelling evidence for large-scale, ITE enriched young mare magmatism within Oceanus Procellarum. In combination with remote sensing data and with the unique Th-rich Apollo 12 basalt fragment 12032,366–18 (impact ejecta likely from Oceanus Procellarum), this implies that significant portions of the FeO- and Th-rich mare regions of the western PKT may also have formed in a similar way. [ABSTRACT FROM AUTHOR]

Deep subsurface exploration is important for mining, oil and gas industries, as well as in the assessment of geological units for the disposal of chemical or nuclear waste, or the viability of geothermal energy systems. Typically, detailed examinations of subsurface formations or units are performed on cuttings or core materials extracted during drilling campaigns, as well as on geophysical borehole data, which provide detailed information about the petrophysical properties of the rocks. Depending on the volume of rock samples and the analytical program, the laboratory analysis and diagnostics can be very time-consuming. This study investigates the potential of utilizing machine learning, specifically convolutional neural networks (CNN), to assess the lithology and mineral content solely from analysis of drill core images, aiming to support and expedite the subsurface geological exploration. The paper outlines a comprehensive methodology, encompassing data preprocessing, machine learning methods, and transfer learning techniques. The outcome reveals a remarkable 96.7% accuracy in the classification of drill core segments into distinct formation classes. Furthermore, a CNN model was trained for the evaluation of mineral content using a learning data set from multidimensional log analysis data (silicate, total clay, carbonate). When benchmarked against laboratory XRD measurements on samples from the cores, both the advanced multidimensional log analysis model and the neural network approach developed here provide equally good performance. This work demonstrates that deep learning and particularly transfer learning can support extracting petrophysical properties, including mineral content and formation classification, from drill core images, thus offering a road map for enhancing model performance and data set quality in image-based analysis of drill cores. [ABSTRACT FROM AUTHOR]

The tectonically complex Indonesian Gateway is part of the global thermohaline circulation and exerts a major control on climate. Waters from the Pacific flow through the Indonesian Archipelago into the Indian Ocean via the Indonesian Throughflow. Much progress has been made toward understanding the near-modern history of the Indonesian Gateway. However, the longer-term climate and ocean consequences of Australia's progressive collision with the Eurasian Plate that created it are less known. The gateway initiated ∼23 Ma, when Australia collided with Southeast Asia. By ∼10 Ma the gateway was sufficiently restricted to create a proto–warm pool. During the Pliocene it alternated between more or less restricted conditions, until modern oceanic conditions were established by 2.7 Ma. Despite its tectonic complexity, climate modeling and Indian and Pacific scientific ocean drilling research continue to yield insights into the gateway's deep history. The Indonesian Gateway is a key branch of global thermohaline oceanic circulation, exerting a major control on Earth's climate over the last 25 Myr. We find that a complex interplay of tectonics and sea level has controlled Indonesian Gateway restriction since 12 Myr, resulting in La Niña– and El Niño–like states in the equatorial Pacific. Long term Indonesian Gateway history is best determined from ocean drilling cores on the Indian and Pacific sides of the Indonesian Gateway, as records from within it are typically disrupted by tectonics. Model simulations show the global impact of the Indonesian Gateway. Further modeling with ocean drilling/tectonic research will enhance our understanding of Cenozoic Indonesian Gateway history. [ABSTRACT FROM AUTHOR]

Large asteroid impacts have long been attributed to imparting long‐lived heat in the upper crust, as well as widespread fracturing and porosity. When an impact occurs on or near an ocean environment, displaced water rushes back filling the crater and percolating down into the fractured crust. The significant heat and fracturing from impact allow for extensive hydrothermal activity. Hydrothermal alteration has been observed at the 180 km Chicxulub impact structure in Yucatán, Mexico. Previous studies estimate widespread hydrothermal transport and activity within the Chicxulub structure, but these processes are largely dependent on the assumed post‐impact permeability distribution. In this work, we present an impact simulation that tracks fragmentation as well as the generation of porosity and permeability during the Chicxulub impact event. The generation of porosity during tensile failure results in final porosities (up to 40%) that are up to a factor of 4 higher than previous models and in better agreement with drill core data. We find that both fragmentation and porosity contribute to overall permeability of the Chicxulub structure. Estimated permeabilities (up to 10−14 m2) are greater than measured values from drill cores because of the contribution from large‐scale fragmentation, which cannot be resolved in cm‐diameter drill cores. The larger porosities and permeabilities computed in this work suggest that the volume of hydrothermal activity generated by Chicxulub were 10 times more than previously estimated for Chicxulub and 100 times more than the Yellowstone caldera. Plain Language Summary: The Chicxulub impact event that led to the extinction of the dinosaurs 66 million years ago hit the Earth on a carbonate platform leaving a 180 km wide impact crater onto what is now Yucatán, Mexico. The impact caused widespread fracturing of the carbonate crust and underlying granite. The extent of this fracturing and what effect it had on hydrothermal activity is of great interest. Several drill cores have been unearthed from within the crater by scientific expeditions. In this work, we build on previous impact simulations of the event using an updated code to model and estimate the extent of fragmentation in the carbonate and granite. Specifically, we model the formation of porosity (void space) and fragmented materials and estimate permeability (the interconnectedness of void space or fractures) and compare with what has been measured and observed in the drill cores for various regions within the crater. We find that the impact likely created more permeable space than what is estimated from drill core data. More permeable space may suggest more hydrothermal activity could be sustained as water from the ocean rushed back into the fractured, warm crust. Hydrothermal systems from the Chicxulub impact may have been 100 times larger than the modern Yellowstone Caldera. Key Points: We simulate impact‐induced porosity with iSALE that is comparable to porosity measured in two different drill coresWe find the permeabilities introduced by the Chicxulub impact event may be greater than those measured from the M0077A and Yax‐1 drill coresThe output from this work will be useful and necessary for constraining the longevity and evolution of hydrothermal systems [ABSTRACT FROM AUTHOR]

Correlating shallow shelf carbonates and their deep basin equivalents is a perennial challenge in the geosciences, with wideranging implications. This hurdle is well illustrated in the Llandovery succession of the Michigan Basin, USA, a 40- to 265-m-thick carbonate interval represented by three lithostratigraphic units: the Cataract, the Burnt Bluff, and the Manistique groups. Although extensively studied at various localities within the basin and across the region, the chronostratigraphic relationships between these units remain unknown. The current study presents a cross-basin chronostratigraphic framework for the Llandovery succession utilizing globally documented carbon (Î'13Ccarb) isotope excursions (CIEs). From 10 drill cores and three quarry sites throughout the Michigan Basin, five CIEs were identified and chronostratigraphically constrained using conodont biostratigraphy and conodont 87Sr/86Sr data. The five excursions are interpreted to be the global CIEs: the (1) Hirnantian Isotope Carbon Excursion (HICE; Hirnantian Stage), (2) Early Aeronian, (3) Late Aeronian (Aeronian Stage), (4) Valgu (Telychian Stage), and (5) Ireviken (Sheinwoodian Stage). Most importantly, the HICE and the Ireviken CIEs bracket the Llandovery strata preserved in the basin. The new high-resolution Î'13Ccarb data suggest that CIEs can be effectively used to correlate among shallow marine shelf carbonates and their deeper water equivalents. The new chronostratigraphic framework shows that CIE-based time horizons across the Michigan Basin cut across lithostratigraphic unit boundaries, which indicates that these lithostratigraphic units are diachronous in the Michigan Basin. In addition to refining the stratigraphy of the Llandovery succession of the Michigan Basin, particularly the timing of various key sedimentary deposits, the new chronostratigraphic framework can be used to: (1) constrain the timing of various regional tectonic phenomena, (2) identify multiple tectonically driven siliciclastic sediment pulses in the basin, and (3) predict various stratal relationships that may result in previously unknown stratigraphic traps and, therefore, new hydrocarbon plays within the basin. The results of the current study also show that Î'13Ccarb trends across the shelf-tobasin transect are spatially and temporally variable and do not match those reported in Modern carbonate settings, which possibly suggests that such Î'13Ccarb trends, to some extent, reflect variations in water circulation and water mass heterogeneity during deposition. [ABSTRACT FROM AUTHOR]

Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Geology & Exploration is the property of Geology & Exploration Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Southeastern China's coastal region is considered one of the key areas for studying prehistoric human–land relationships in the Western Pacific region. This region, which is rich in records of marine civilization, provides an ideal location for recording coastal environmental evolution. In this study, the chronological framework of three borehole cores recovered from Haitan Island, South China, near the Keqiutou group of sites, was established using both optically stimulated luminescence (OSL) and accelerator mass spectrometry radiocarbon (AMS 14C) dating techniques. Various analyses, including lithologic characteristics, chroma, clay–water electric conductivity (EC), grain size and elemental geochemistry, were conducted to elaborate the sedimentary sequence and its paleoenvironmental implications. The findings suggest that (i) since the late Quaternary, the Haitan Island sedimentary sequence can be divided into three deposition stages: Old Red Sand formed during Marine Isotope Stage 3 (MIS3), intermittent sedimentation during the Last Glacial Maximum and coastal aeolian deposition during the Holocene. Furthermore, the study reveals that terrestrial debris was significant as a material source for Haitan Island. (ii) Due to the absence of tectonic uplift, Haitan Island has no thick marine sedimentary record during the Holocene period of high sea level. The Luyangpu coastal sand sheet can be dated to 2.78 ka, which is consistent with previous reports giving dates of 2.4 ka. Prior to the formation of the sand sheet, the sedimentary environment in the area was characterized by lagoon or marsh facies. (iii) Paleoanthropological activities were influenced by sedimentary environmental evolution and geomorphic processes, among others. The Keqiutou Culture experienced high sea levels, which created an intertidal environment near the site and facilitated fishing. However, regression at 5.7 ka led to terrestrial environments, which prompted the inhabitants to migrate. Approximately 3 ka ago, sea levels rose again, coinciding with the initiation of rice cultivation. These factors may have influenced the transition from the Neolithic to Bronze Age culture. This study reconstructs evolution of the sedimentary sequence since the late Quaternary, enhancing our understanding of past human–terrestrial relationship in the region. [ABSTRACT FROM AUTHOR]

Rock quality designation (RQD) characteristics for assessing the degree of rock mass fracture make it a key parameter in rock grading or other rating systems. Traditional core characterization relies on subjective manual visual inspection by geologists. Currently, convolutional neural networks are used in borehole images to classify intact and nonintact cores in core rows for automatic RQD estimation. Classification networks cannot predict the exact locations of the intact cores, and drill core characterization is not intuitive. Alternatively, an attention mechanism combining channel and spatial attention modules is proposed to improve the YOLOv5 algorithm for drill core characterization. The model was trained on 657 artificial core tray images generated by the developed preprocessor to accurately predict the bounding boxes of the intact cores on the row centerline, and the automatic RQD calculation of the row was implemented with the developed postprocessing program. Our method performed RQD estimation on 602 new granite rows and 180 new quartz sandstone rows, with average error rates of 1.27% and 1.12%, respectively. It processed 50 m of cores on average in 1 s on a GPU. Furthermore, this method provides an innovative method for automatically processing and quantifying geological image databases. Highlights: Drill core images are automatically analyzed to estimate the RQD of the rows. An attention mechanism combining channel and spatial attention modules is proposed. YOLOv5 is combined with an attention mechanism for detecting intact cores. The proposed method is tested on granite and quartz sandstone images, yielding an average error rate of 1.24%. [ABSTRACT FROM AUTHOR]

According to the 'trapped liquid' paradigm, whole-rock chemical compositions of cumulate rocks in layered intrusions can be represented as closed-system multicomponent mixtures of the cumulus phases and the liquids from which they crystallised. Alternative open-system models for cumulate solidification assert that intercumulus liquid is continuously mobile as a result of compaction of crystal mushes. In the closed-system models, all excluded elements, i.e. those incompatible in the cumulus phases, should be correlated with one another, whereas in open systems the more incompatible elements should be decoupled from the more compatible ones and correlations should be poor. These alternative hypotheses are tested using a database of >63 000 whole-rock analyses of mostly ultramafic cumulates from a single package of layers across the entire width of the Mirabela layered intrusion, a 2.5-km-wide by >2-km-thick intrusion with Great Dyke-like stratigraphy. Variably compatible elements Al, Na, Ti and P are found to show strong correlations with one other in olivine-pyroxene cumulates across the spectrum from mesocumulate to orthocumulate rocks, where drill-core sample intervals are composited over 3 m; weaker correlations are found over 1-m sample intervals. The closed-system trapped liquid model is robust for this suite of rocks at the scale of 3-m lengths of drill core (~1 kg of sample). Furthermore, a very smooth and symmetrical variation is observed from dominantly ad- to mesocumulate rocks in the geometrical centre of the intrusion towards orthocumulates at both margins, attributable to increase in cooling rate towards the margins. The most adcumulate rocks are gabbronorites at the base of the mafic sequence in the centre of the intrusion. There is no corresponding decrease in layer thickness towards the centre that would be predicted by a compaction model. The only incompatible element showing partial decoupling is K, which appears to have been mobile at a very late stage, probably in an aqueous fluid phase. There is no evidence for mobilisation of platinum group elements or other chalcophile elements by this fluid despite the presence of disseminated sulfide throughout the sampled interval. [ABSTRACT FROM AUTHOR]

Three seasonally resolved ice core records covering the 20th century were extracted in 1994, 2004, and 2012 at a nearly identical location from the Col du Dôme (4250 m above sea level, m a.s.l.; Mont Blanc, French Alps) drill site. Here, we complete and combine chemical records of major ions and radiometric measurements of 3 H and 210 Pb obtained from these three cores with a 3D ice flow model of the Col du Dôme glacier to investigate in detail the origin of discontinuities observed in the depth–age relation of the ice cores drilled in 2004 and 2012. Taking advantage of the granitic bedrock at Col du Dôme, which makes the ice core 210 Pb records sensitive to the presence of upstream crevasses, and the fact that the depth–age disturbances are observed at depths for which absolute time markers are available, we draw an overall picture of a dynamic crevasse formation. This can explain the non-disturbed depth–age relation of the ice core drilled in 1994 and the perturbations observed in those drilled in 2004 and 2012. Since crevasses are common at high-Alpine glacier sites, our study points to the important need for rigorous investigations of the depth–age scale and glaciological conditions upstream of drill sites before interpreting high-alpine ice core records in terms of atmospheric changes. [ABSTRACT FROM AUTHOR]

Grigoriev ice cap, located in the Tien Shan mountains of Kyrgyzstan, has a rich history of firn and ice core drilling starting as early as 1962. Here we extend the exceptional record and describe an 18 m firn core, drilled in February 2018 on the summit of Grigoriev ice cap, at 4600 m a.s.l. The core has been analyzed for firn stratigraphy, major ions, black carbon, water stable isotope ratios and total β activity. We find that the core covers 46±3 years and overlaps by 2 to 3 decades with legacy cores. A good agreement is found in major ion concentrations for the overlapping period. Concentrations of black carbon and major ions are reduced since the early 2000s, indicating the onset of meltwater runoff. Nevertheless, general concentration trends of these species are consistent with observations and Central Asian ice core records, since emissions were highest during periods when melt influence was negligible. The record of water stable isotopes does not reflect the strong increase of air temperatures during the last decades, implying that water stable isotope ratios ceased to be proxies of temperature variations at this site. Apart from runoff evidence, however, the firn's thermal regime appears remarkably unchanged. Firn temperatures in 2018 were the highest on record (∼-1.6 °C at ∼17 m depth). However, temperatures in 2023 are again similar to the early 2000s at ∼-2.5 °C. Furthermore, we find little change in net accumulation since the 1980s. We hypothesize (i) that firn temperatures are stabilized by the removal of latent heat through lateral meltwater runoff, and (ii) that mass loss by runoff is compensated by an increase in accumulation. Data from a nearby weather station support the latter hypothesis. [ABSTRACT FROM AUTHOR]

The state of stress in a mining front constantly changes with mining activities. In a recent study, the authors developed and verified with laboratory measurements an analytical model for the calculation of mining-induced stresses based on measuring the deformations of a diamond drill rock core extracted perpendicular to the mining front or face. The method is called diametrical core deformation technique (DCDT). In this study, the DCDT is used in combination with 3D numerical modelling to develop a practical methodology for the assessment of mining face stability. To demonstrate the methodology, a diamond drill rock core was retrieved from an access drift face 530 m below the surface of an underground mine in northern Quebec. The state of stress in the mining front is estimated from the DCDT and used to adjust the orientation and principal stress magnitudes in the local area around the access drift in a 3D linear-elastic numerical model using an iterative approach. As the rock core is partially fractured due to previous face advance blasting, the numerical model is further adjusted to model the observed damage zone. The 3D model after adjustments is used to examine the mining front stability with the Hoek–Brown failure criterion. It is postulated that the proposed methodology is suitable for the stability assessment of any mining front with or without an observed damage zone. [ABSTRACT FROM AUTHOR]

Many styles of gold mineralisation are challenging to sample because of the presence of coarse gold and a high spatial heterogeneity. The coarse gold-bearing conglomerates of the Beatons Creek deposit provide some challenges related to the presence of gold particles up to 8 mm and gold particle clusters (up to 500 mm3) at low in situ grades (<2 g/t Au). Novo has attempted to address these issues over the last six years of exploration, resource development and mining. The Beatons Creek open pit operation was the first Pilbara conglomerate-hosted gold deposit to go into production. Between January 2021 and September 2022, it produced 2.5 Mt at 1.2 g/t Au for 87,300 oz Au recovered. Gold is present within a matrix of multiple, narrow-stacked oxide and fresh (sulphide) conglomeritic reef horizons, which are interbedded with unmineralised conglomerate, sandstones and grits. It is strongly associated with detrital pyrite and authigenic nodules. Several sampling techniques have been applied across the project, including diamond core and RC drilling, trench channel sampling and bulk sampling. Assay methods applied include fire assay, screen fire assay, LeachWELL™ and more recently PhotonAssay™. The dominant sampling protocol applied for resource development and grade control utilised 0.5 m length RC samples; a 50% rig split (c. 8.5 kg) and laboratory crushing to 3 mm, followed by a 2.5 kg split and total assay via PhotonAssay™. For part of the 2022 RC programme, the detectORE™ technique was used to screen primary RC samples and reduce the feed to the laboratory. Novo operated a sampling and assay programme that aimed to reduce the impact of coarse gold on sample and assay preparation biases and to improve estimation. [ABSTRACT FROM AUTHOR]

Advanced geological prediction plays an essential role in disaster prevention and safety guarantee. In this paper, by combining multiwavelet analysis with modified evidence reasoning, a new geological prediction method for surrounding rock in a tunnel considering the parameters' coupling effect was proposed. Based on the key drilling parameters' curves that were denoised in the No. 1 hole of the Xiaochuan tunnel in Gansu Province, China, the coupling effect of these parameters were analyzed and the power–speed ratio (PSR) concept was thereby proposed to deal with the denoised curves and obtain a PSR curve. Through continuous wavelet transform (CWT) of the PSR curve, the lithology and structure were preliminarily determined by sectional matching and optimization of multiple wavelet coefficient curves under the optimal scales and PSR curve. Further, the evidence reasoning was introduced to solve the uncertainty parts in the preceding result. To avoid misjudgment caused by the limitation of Dempster Shafer (D-S) theory in the case of complete conflict, it was modified, in which the basic probability assignment (BPA) was determined by the interval number, and a binary group was then defined by combining the traditional conflict coefficient with pignistic probability distance to measure the degree of conflict. The division result that settled by this method showed greater accuracy than tunnel seismic prediction (TSP) and the drilling core, also could give a clear division for both lithology and structure. Importantly, by applying the established method to Chengzhou tunnel, the result fitted the real condition well. This approach provides references for rock prediction in tunnels. [ABSTRACT FROM AUTHOR]

The Midcontinent Rift System of North America is one of the oldest continental rifts but rifting ceased before continental breakup. The southern segment of the Midcontinent Rift System lies in Kansas, USA, where the stratigraphic succession and rift evolution are largely unknown. This study analysed the rift basin infill in this part of the Midcontinent Rift System to propose a depositional model. The Precambrian rift succession was described in discontinuous cores drilled in the Texaco Noel Poersch#1 well in Washington County. Sixteen lithofacies were identified and grouped into four different facies associations (fluvial, aeolian, lacustrine and alluvial fan). Overall, the studied succession comprises continental deposits accumulated dominantly in alluvial and aeolian settings, with the intermittent development of lacustrine systems. The proposed depositional models for the available core intervals indicate cyclic patterns of overfilled and underfilled phases within the rift basin. These changes in the accommodation‐to‐supply ratio were controlled by tectonism and probably modulated by climate during evolution in the syn‐rift phase. This study advances our understanding of variations across the Midcontinent Rift System. [ABSTRACT FROM AUTHOR]

Martian rocks contain crucial information about the genesis of Mars and the historical evolution of Martian climate change. Consequently, extracting and examining Martian rocks are pivotal in advancing our comprehensive understanding of the red planet. However, the current core drill string is prone to wear and tear, and the samples are susceptible to thermal denaturation. To address these challenges, we introduce two novel types of drill bits, the conical straight junk slot and the conical spiral junk slot, both employing impregnated diamond as the primary material. Comparative experiments were meticulously conducted to evaluate the influence of different junk configurations on drilling parameters, including speed, abrasion resistance, drilling force loading, and sample temperature rise. The findings unequivocally demonstrate the superior performance of the spiral junk slot. Furthermore, simulations were performed to examine the drilling process on basalt using a fixed configuration drill bit, validating the occurrence of the sample temperature rise. The research presented in this paper offers valuable programmatic references and essential data support for future Martian rock coring drilling missions. [ABSTRACT FROM AUTHOR]

We explored the geological history of the Taurus‐Littrow Valley at the Apollo 17 landing site through the induced thermoluminescence (TL) properties of regolith samples collected from the foothills of the Northern and Southern Massifs, from near the landing site, and from the deep drill core taken in proximity to the landing site. The samples were recently made available by NASA through the Apollo Next Generation Sample Analysis program in anticipation of the forthcoming Artemis missions. We found that the two samples from the foothills of the massifs exhibit induced TL values approximately four times higher than those of the valley samples. This observation is consistent with their elevated plagioclase content, indicating their predominantly highland material composition. Conversely, the valley samples display induced TL values characteristic of lunar mare material. The samples from the deep drill core demonstrate uniformly induced TL properties, despite originating from depths of up to 3 m. Notably, one of the samples from the lower section of the deep drill core presents anomalous‐induced TL readings. This anomaly coincides with elevated levels of low‐potassium KREEP along with reduced quantities of anorthositic gabbro and orange glass, and could be due to the traces of phosphate minerals. Alternatively, this observation raises the possibility that this sample contains Tycho impact material. The induced TL data is consistent with the regolith, extending to a depth of at least 3 m, having been deposited by a singular event approximately 100 million years ago. This timing aligns with the hypothesized formation of the Tycho crater. Plain Language Summary: We studied the geologic history of the Taurus‐Littrow Valley through the induced thermoluminescence (TL) properties of Apollo 17 regolith samples. Thermoluminescence refers to the light emission of a sample when it is heated. Our investigation focused on samples that were collected from the foothills of the Northern and Southern Massifs, from near the landing site, and from the deep drill core taken in proximity to the landing site. We found that samples from the foothills of the massifs induced TL levels four times higher than those from the valley floor. We attribute this difference to their differing plagioclase content, whereby the TL of foothill samples is comparable to highland material, and valley floor TL is comparable to mare material. The induced TL properties in the deep drill core are mostly uniform. However, one of the samples within the lower section of the deep drill core exhibited anomalous‐induced TL levels. This coincides with elevated levels of low‐potassium KREEP along with reduced quantities of anorthositic gabbro and orange glass, which could be due to traces of phosphate minerals. Alternatively, this sample may contain Tycho impact material. Our TL data suggest that the valley floor regolith was deposited by a single event approximately 100 million years ago, aligning with the hypothesized formation of the Tycho crater. Key Points: The samples from the deep drill core demonstrate uniformly induced TL propertiesThe TL anomaly in the lower section of the deep drill core coincides with elevated KREEP level. Alternatively, anomalies may represent Tycho materialTL data suggest deposition of valley regolith of at least upper 3 m during a single event, potentially 100 Mya during Tycho impact [ABSTRACT FROM AUTHOR]