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Due to the escalating demand for conventional potassium sources, and their unavailability in many African countries, there is a growing interest in hydrothermally treated igneous rocks as viable alternatives. These materials exhibit promising potential in enhancing potassium release, comparable to traditional sources like muriate of potash (M.O.P.). However, it remains uncertain whether they can adequately fulfill the nutrient requirements of plants. In this study, we evaluated nutrient balance in ryegrass (Lolium multiflorum) using raw and hydrothermally treated K-bearing silicate rocks as fertilizers. The Compositional Nutrient Diagnostic (CND) approach was used to assess the plants' nutrient status, involving identification of high-yield subpopulations, and setting a yield cutoff. We derived a theoretical threshold for nutrient imbalance (CNDr2) using statistical methods like the chi-square distribution function and low-yield subpopulation proportion. CNDr2 was validated via Cate–Nelson partition and sum of squared individual nutrient indexes. Results showed a yield cutoff of 37.759 kg ha−1, distinguishing low-yield and high-yield subpopulations based on cumulative variance ratio functions from survey data. The theoretical threshold derived using the chi-square function was 10.1, subsequently validated by the Cate–Nelson method. Critical CND nutrient indices were symmetrical around zero, but their sum indicated foliar nutrient imbalance, notably zinc, potassium, and copper excess, attributed to 20 interactions identified (4 synergetic and 16 antagonistic). This study underscores hydrothermal treatment's efficacy in improving nutrient availability and achieving a balanced nutrient profile compared to raw materials. It offers a promising solution for enhancing agricultural productivity, especially in tropical regions like Africa, where traditional sources are scarce. [ABSTRACT FROM AUTHOR]

How gabbro affects the generation and expulsion of hydrocarbons in muddy surrounding rocks is clarified by analyzing thin section, major and trace elements, total organic carbon (TOC), pyrolysis, extracts and vitrinite reflectance data from source rocks in the Chunxi area the Dongying Sag, Bohai Bay Basin, eastern China. The results show that a magma intrusion brings copious heat to the source rocks, which promotes abnormal maturation of organic matter (OM) and rapid hydrocarbon generation. The CH4 and H2 produced by gabbro alteration play a role in hydrocarbon generation of source rocks. The hydrothermal process during magma intrusion provides many different minerals to the source rock, resulting in carbonate‐rich surrounding mudstone. The carbonate and clay minerals produced by volcanic mineral alteration jointly catalyze the hydrocarbon generation of the source rock. The high‐temperature baking of the intrusion results in hydrothermal pressurization and hydrocarbon generation pressurization, causing many fractures in the surrounding rock. The generated oil and gas are discharged through the fractures under diffusion and pressure. Mantle‐derived CO2 is also conducive to the expulsion of hydrocarbons because of its strong enrichment capacity for hydrocarbons. [ABSTRACT FROM AUTHOR]

Penelitian tentang karakteristik batuan beku dapat berkontribusi pada penelitian lanjut tentang potensi sumber daya lainnya yang terkait dengan fenomena magmatisme, khususnya di lokasi yang memiliki sejarah magmatisme cukup panjang seperti di bagian barat Pulau Jawa. Studi karakteristik petrologi batuan beku pada penelitian ini dilakukan dengan menggunakan sampel yang diperoleh dari Cikalongkulon, Cianjur, Jawa Barat; sebuah lokasi dengan kompleks tubuh intrusi yang membentang hampir Barat-Timur. Dilakukan pengamatan lapangan dan petrografi guna menghasilkan sintesis terkait interaksi antaran tubuh batuan beku dan batuan samping di daerah penelitian. Dari observasi didapati bahwa terdapat metasomatisme yang terjadi akibat proses intrusi andesit terhadap batuan samping. Proses ini terjadi pada rentang suhu 270-320°C yang ditandai oleh kemunculan mineral sekunder berupa klorit, serisit, kalsit, kuarsa, dan epidot. Keberadaan metasomatisme ini juga mengindikasikan bahwa umur tubuh intrusi andesit harus lebih muda dari Miosen Tengah, berbeda dari interpretasi awal pada Peta Geologi Lembar Cianjur yang menempatkan tubuh batuan beku lebih tua dari batuan sedimen di sekitarnya.

Abstract The geological phenomenon of igneous rock invading coal seam is widely distributed, which induces mining risk and affects efficient mining. The pre-splitting blasting method of igneous rock is feasible but difficult to implement accurately, resulting in unnecessary safety and environmental pollution risks. In this paper, the blasting model with penetrating structural plane and the multi-hole blasting model with different hole spacing were established based on the Riedel–Hiermaier–Thoma (RHT) damage constitutive to explore the stress wave propagation law under detonation. The damage cloud diagram and damage degree algorithm were used to quantitatively describe the spatio-temporal evolution of blasting damage. The results show that the explosion stress wave presents a significant reflection stretching effect under the action of the structural plane, which can effectively aggravate the presplitting blasting degree of the rock mass inside the structural plane. The damage range of rock mass is synchronously evolved with the change of blasting hole spacing. The blasting in the igneous rock intrusion area of the 21,914 working face is taken as an application example, and the damage degree of rock mass is reasonably evaluated by the box-counting dimension and K-means clustering method, which proves the effectiveness of the blasting scheme and provides reference value for the implementation of related blasting projects.

This paper presents a complete map of the Mesozoic volcanic-plutonic complexes in the Taiwan Strait and its adjacent areas in terms of seismic profiles, ages, geochemistry, isotopic systematics, and published data. Two periods of igneous activity in the Taiwan Strait can be distinguished by seismic profiles: Jurassic (200.4–148.2 Ma); and Latest Jurassic/Cretaceous to Maastrichtian (144–66 Ma), of which the Cretaceous is the best preserved and could possibly be the most widespread. Mesozoic magmatic activity with the NE-striking distribution was migrating southeastward (oceanward). LA-MC-ICPMS zircon U – Pb dating yields the age data of 109.5 ± 0.4 Ma for PTDH1 granodiorite and 92.6 ± 0.4 Ma for PTDH4 rhyolite in the Taiwan Strait, respectively. The 581.66-m-thick Upper Jurassic volcanic rocks of the Chuan2 well are the thickest Mesozoic igneous rocks in the Taiwan Strait. The petrogenetic discrimination diagram of the Cretaceous volcanic-plutonic complexes along the coast of South China and the Taiwan Strait generally is belonging to volcanic arc or intraplate type calc-alkaline rock series. The high potassium calc-alkaline rock series of the Cretaceous volcanic-plutonic complexes that is most widely distributed in the coastal areas of South China and the Taiwan Strait. They are controlled by the subduction of the Palaeo-Pacific domain. [ABSTRACT FROM AUTHOR]

Background. Development of thermal insulation materials production requires new innovative approaches to their production technologies. Purpose. Study of chemical and mineralogical compositions of Shehzheli basalt for obtaining thermal insulation materials. Methodology. X-ray phase analysis methods were used (Shimadzu LABX XRD-6100). Phase identification was carried out according to reference books and the ICDD PDF-2 database. Originality. It was revealed that the main mineral of the basalt rock of the studied deposit is a feldspar mineral - albite. Findings We obtained data from X-ray phase analysis of samples, their chemical and mineralogical composition is similar to traditional basalt rocks, in the composition - minerals albite, quartz, chlorite, calcite. [ABSTRACT FROM AUTHOR]

Background. Production of basalt fiber materials for thermal insulation materials, based on igneous rocks, meets the requirements of world standards. Purpose. Comparative analysis of chemical and mineralogical compositions and structures of igneous rocks for obtaining basalt fibers. Methodology. The studies were carried out using modern physicochemical methods adopted in the technology of mineral (basalt) fibers and thermal insulation materials. Originality. Chemical and mineralogical compositions and structures of various igneous rocks from different deposits were determined to establish their suitability for obtaining basalt fibers. Findings. The content of the main rock-forming components of igneous rocks was determined, their structure and properties were studied. [ABSTRACT FROM AUTHOR]

In order to investigate the influence of igneous rock powder and silica fume on the performance of cement mortar, facilitate the application of igneous rock powder in engineering, and promote the greening of the cement industry, this study examined the pozzolanic activity of three different types of igneous rock powders: granite, andesite, and tuff. It explored the workability and mechanical properties of both binary systems (igneous rock–cement) and ternary systems (igneous rock–silica fume–cement). Microscopic techniques including X-ray diffraction (XRD), thermogravimetric analysis–differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), and nitrogen adsorption were used to investigate the mechanisms of how different types of igneous rock and silica fume affect the cementitious systems. The results showed that the pozzolanic activity of igneous rock powders was relatively weak, and their inclusion at levels below 20% had minimal impact on the flowability of cement mortar. In fact, within the 20% inclusion range, andesite powder even increased the flowability. Co-blending igneous rock powders with silica fume promoted the early hydration of cement, resulting in reduced calcium hydroxide (CH) content in the hydration products. The most significant increase in strength of the cement mortar system was observed when 5% to 10% (by mass) of igneous rock powder and 5% to 10% of silica fume were used as replacements for cement. The highest cement mortar strength was achieved when 10% andesite and 10% silica fume were used as replacements, resulting in a compressive strength of 52.2 MPa. [ABSTRACT FROM AUTHOR]

Finding stone aggregates with desirable properties in terms of durability for use in railway ballast is one of the most important concerns of railway projects. This study investigated the suitability of some types of igneous rocks (acidic to basic groups) for use as railway ballasts in Yazd Province, Iran. Los Angeles abrasion (LAA) and MgSO4 test results for the samples were compared. The results revealed that the acidic rock group, especially dacite samples, showed lower LAA and MgSO4 weight loss compared with the basic rock group. The LAA and MgSO4 weight loss values decreased with increasing SiO2 content in both acidic and basic rocks. With an increase in Al2O3 , the MgSO4 weight loss increased for acidic rocks and decreased for basic rocks. Normative mineralogy content was meaningfully correlated (R2>0.93 in multivariate regression) with the LAA and MgSO4 weight loss values. The chlorite carbonate pyrite (CCP) weathering index, which is defined based on changes in mineralogical content, showed a strong positive relationship with the LAA. Also, the Ruxton ratio index R (SiO2/Al2O3) showed good to very strong correlations with MgSO4 weight loss. The porphyry ratio index (PR) did not individually succeed in predicting the durability properties. Therefore, the PR was used along with porosity and geochemical properties to estimate the LAA and MgSO4 weight loss. The use of variables of porosity, the PR and SiO2 and Al2O3 oxides developed very strong and reliable relationships (R2>0.98) to estimate the LAA and MgSO4 weight loss. [ABSTRACT FROM AUTHOR]

Indonesia is surrounded by three tectonic plates: the Eurasian, Indo−Australian, and Pacific plates. The plates have caused Indonesia to have many volcanoes, both active and inactive, resting, or no longer active. One of the volcanoes belonging to the formed “Rest” category is the ancient Lawu volcano. The mountain is 10,000 radiocarbon years old or approximately 11,430 ​± ​130 calendar years ago, which is part of the Holocene age. The Lawu volcano erupted on November 28, 1885. This paper discusses the study of magnetic minerals in the case of pyroclastic flows originating from Mount Lawu. The values obtained in magnetic susceptibility are 47.53 ​× ​10−6 ​m³/kg to 79.41 ​× ​10−6 ​m³/kg. The results of this susceptibility measurement indicate the presence of igneous rocks resulting from pyroclastic flow. Furthermore, the vibrating sample magnetometer test showed an S−type (ferromagnetic) hysteresis curve, and the value of Mr/Ms (remanence ratio) define was below 0.5, which realized a multi-domain configuration. This ferromagnetic characteristic is attributed to the iron-based mineral (10.4%–17.1%) from the evaluation of X−Ray Fluorescence. The magnetite mineral confirmed in the X-Ray Diffractometer test is the largest source of magnetism in the sample. [ABSTRACT FROM AUTHOR]

Mesozoic igneous rocks are widely distributed in the South China Sea (SCS) and its adjacent areas and are exposed in the SCS, South China, Hainan, Indochina, Taiwan, the Philippines, and Borneo; these rocks are mostly dominated by granitoids. This paper presents a complete map of the Mesozoic igneous rocks of the SCS and its adjacent areas. This paper also presents an analysis of geological survey and published data in terms of seismic profiles, ages, geochemistry and isotopic systematics of the Mesozoic igneous complexes of the SCS and its adjacent areas. Three periods of igneous activity can be distinguished: (1) Permian – Triassic that spans from 250–201 Ma; (2) Jurassic (201–145 Ma); and (3) Latest Jurassic/Cretaceous to Maastrichtian (145–66 Ma), of which the Cretaceous is the best preserved and could possibly be the most widespread. Triassic igneous rocks are distributed in the northwestern and southern SCS (Qiongdongnan Basin, Yinggehai-Song Hong Basin, Beibu Gulf Basin, the Dangerous Grounds, and the Reed Bank); Jurassic igneous rocks are distributed in the northern and southern SCS (Pearl River Mouth Basin, Qiongdongnan Basin, Yinggehai-Song Hong Basin, Beibu Gulf Basin, and the Reed Bank); and Cretaceous igneous rocks are distributed in the northern, western and southern SCS. The igneous activity of the SCS is mostly distributed in the continent slope. Mesozoic igneous rocks of the SCS include at least 350 rock masses: the smallest being 0.182 km2, the largest being 5,5,502 km2, and the total area covering 688,539 km2. Mesozoic magmatism in the SCS and its adjacent areas migrated oceanward (southeastward). Our new seismic profiles and the wells from the literature highlight that Jurassic granites occur not only inland of South China but also in coastal South China and the northern and southern SCS. The YING6 well in the northern SCS encountered andesite with an age of 68.24 Ma, which is the youngest age found for the SCS Mesozoic volcanic rocks. The XY1 well in the western SCS encountered granite with an age of 68.9 Ma, which is the youngest age found for the SCS Mesozoic intrusive rocks. The WZ12-3-1 well in the northern SCS encountered granite with an age of 243.3 Ma, which is the oldest age found for the SCS Mesozoic intrusive rocks. The encountered dacite ages (219.1 ± 1.4 Ma) of the NK-1 well in the southern SCS were the oldest ages found for the SCS Mesozoic volcanic rocks. The thickest Mesozoic igneous rocks (>1022.5 m) were encountered in the NK-1 well. Igneous rocks in the SCS and its adjacent areas are closely related to tectonic movements such as faults, plate movement, and mantle-derived igneous fluid ascent. They are controlled by the subduction of the Tethys lithospheric and Paleo-Pacific domains. [ABSTRACT FROM AUTHOR]

Nearly 20 passive continental margin basins developed on both sides of the South Atlantic Ocean, and a number of major oil and gas discoveries obtained in deep-water areas, however, a lack of understanding of the geological characteristics of the passive continental margin basins resulted in the low level of exploration in deep-water areas, and the amount of oil and gas resources to be discovered was enormous. For this reason, on the basis of comprehensive analysis of a large amount of data and cases, and fully combining the study results and understanding in recent years, the key geological characteristics of the passive continental margin basins in the middle and southern part of both sides of the South Atlantic Ocean were systematically summarized, and the impact of the geological features on the exploration of oil and gas was deeply analyzed. The study shows that igneous rocks of 3 orogenic types and 3 active phases are widely developed throughout the rifting period in the basin complex on both sides of the South Atlantic Ocean; in the southern section, the thick, seaward-tilted reflective wedges are widely developed in the volcanic passive continental margin basin; in the middle section, the salt rock planar distribution and thickness change rule of the salt rock development type basin complex has both similarity and difference between the two banks, and the salt cementation of the subsalt sandstone reservoir may occur; dirty salts are developed in the Gabon Basin, Santos Basin, Campos Basin, and Lower Congo Basin; the Kwanza Basin in the middle section of West Africa has become the only saltstone - hard gypsum - carbonate interbedded sedimentary basin on both sides of the South Atlantic Ocean due to the cyclonic evaporation pattern, and the thinner inter-salt carbonate layer is both a hydrocarbon source rock and a reservoir. The above geologic characteristics have a great impact on the prediction of the subsalt seismic imaging, subsalt reservoirs, hydrocarbon source rocs and inter-salt carbonate rocks, and increase the multiplicity of solutions for seismic exploration. This study provide a basis for the precise positioning of the future technical attack direction of the passive continental margin basin. [ABSTRACT FROM AUTHOR]

Santos Basin is characterized by multiple phases of magmatic events and widespread distribution of igneous rocks, which have significant affect of hydrocarbon accumulation. Taking Block C of Santos Basin as a typical and representative example, this paper focused on the characteristics of igneous rocks and their roles in hydrocarbon accumulation through the analysis of igneous rock petrology, geochronology, petrogeochemistry, and gas isotopes. In Block C, at least two main stages of magma events were developed: Aptian magma (122.8±0.6-110.8±0.6 Ma) and Santonian-Campanian magma (84.2±0.7-77.4±0.4). The Aptian magma is dominated by eruptive rocks and has experienced dozens of eruptions, accompanied by several layers of subvolcanic rocks. In comparison, Santonian-Campanian magma is distributed in a relatively random pattern. The multipulse eruption of Aptian magma formed an igneous rock-coquinas complex of more than 600 meters in thickness, inducing a local paleohigh in Itapema Formation. This directly caused the trap crest to shift and contributed to the development of high-quality carbonate deposition in Barra Velha Formation. Before the eruption of Aptian magma, the north flank of Block C was paleohigh, where a particular scale of microbial carbonate reservoirs was anticipated to develop in the Barra Velha Formation as well. These carbonate reservoirs were favorable for hydrocarbon accumulation. The later Santonian-Campanian intrusions also impact carbonate reservoirs through hydrothermal fluid circulation and contact metamorphism. Meanwhile, a large amount of associated CO2 accumulated in the trap led to a high GOR (gas oil ratio) and high CO2 content and changed the fluid composition through the extraction process.A CO2 gas reservoir with condensed oil was eventually formed in the current crest in Block C, as proven by drilled well A.Another pool with high CO2 content is also expected in its north flank, to be demonstrated in the future.

Abstract The X oilfield is the first sandstone reservoir under the influence of igneous rock, which is discovered and put into development in Bohai Sea. Compared with the conventional sandstone reservoir, the oilfield is affected by magmatic activity, the reservoir heterogeneity is serious and the micro pore structure is complex, which results in the poor correlation between mobility calculated by traditional methods and specific oil production index. In order to predict oil well productivity and guide oilfield well location deployment, the quantitative transformation of sandstone reservoir affected by igneous rock is studied in this paper. According to the distribution mode of igneous rock in the reservoir, a permeability model of quantitative characterization for sandstone reservoir permeability is established, in which the influences of heat conduction, reservoir skeleton deformation and stress sensitivity are considered, and then the igneous rock influence on the ground temperature field of surrounding rock is simulated by ANSYS software. According to the relationship between porosity and permeability, the quantitative transformation effect of igneous rock thermal effect on sandstone reservoir is quantitatively characterized. The reservoir temperature field variation law, different baking types and igneous rock thickness influence on the transformation degree of sandstone reservoir are analyzed. Finally, the X oilfield is taken as an example to verify the research method, and the second batch of wells location deployment is successfully guided. The results show that the thermal effect of igneous rock reduces the permeability of reservoir, and the temperature of reservoir increases first and then decreases with time, the rising speed is faster than the falling speed, with the increase in distance from igneous rock, the maximum temperature of reservoir shows a downward trend, in the case of baking on both sides, the heat of igneous rock is greater, which makes the temperature of surrounding reservoir rise more, and the transformation effect on reservoir is more obvious. The influence range of igneous rock thickness on permeability is basically the same, but with the increase in thickness, igneous rock has a greater influence on surrounding rock. The research example of the X oilfield shows that the existence of igneous rock reduces the reservoir physical properties of development wells by 1.2–5.9 times. The correlation between igneous rock physical properties and specific oil production index corrected by this method can reach 0.9478. By avoiding igneous rock, the comparative production of the second batch of development wells is 1.5 times that of the first batch of development wells.

Due to the intrusion of igneous rocks, conventional clastic formations are not only divided and modified by igneous rocks on a macroscopic scale but the pore structure of sandstones is also altered by complex physicochemical effects on a microscopic scale. The strong planar and longitudinal inhomogeneity of the reservoir poses difficulties for well test interpretation. Based on the theory of seepage mechanics and mathematical-physical methods, a well test model with arbitrary combinations of multi-layer and multi-zone composite features is established for the non-homogeneous characteristics of sandstone reservoirs. The main factors affecting the bottom-hole pressure dynamics are analyzed. The results show that the composite reservoir characteristics and boundary conditions of the high permeability layer are mainly reflected at the early stage of the system flow phase, while those of the low permeability layer is mainly reflected at the late stage of the system flow phase. When the reservoir boundary is closed or at constant pressure, the pressure derivative curve will undergo an upward or downward shift in response. The case analysis proves the reliability and practicality of the model, and the research results provide theoretical support for the interpretation of test wells in similar reservoirs. [ABSTRACT FROM AUTHOR]

Predicting the lithology, lithofacies and reservoir fluid classes of igneous rocks holds significant value in the domains of CO2 storage and reservoir evaluation. However, no precedent exists for research on the multi-label identification of igneous rocks. This study proposes a multi-label data augmented cascade forest method for the prediction of multi-label lithology, lithofacies and fluid using 9 conventional logging data features of cores collected from the eastern depression of the Liaohe Basin in northeastern China. Data augmentation is performed on an unbalanced multi-label training set using the multi-label synthetic minority over-sampling technique. Sample training is achieved by a multi-label cascade forest consisting of predictive clustering trees. These cascade structures possess adaptive feature selection and layer growth mechanisms. Given the necessity to focus on all possible outcomes and the generalization ability of the method, a simulated well model is built and then compared with 6 typical multi-label learning methods. The outperformance of this method in the evaluation metrics validates its superiority in terms of accuracy and generalization ability. The consistency of the predicted results and geological data of actual wells verifies the reliability of our method. Furthermore, the results show that it can be used as a reliable means of multi-label prediction of igneous lithology, lithofacies and reservoir fluids. [ABSTRACT FROM AUTHOR]

Wellbores drilled in igneous formation with weak interlayers face significant risk of instabilities. This study aims to investigate the underlying mechanisms of these instabilities by employing a combination of rock mechanics tests and numerical simulation techniques. The mechanical properties of igneous rocks are evaluated to determine core strength parameters and analyze the impact of drilling fluid immersion on core strength. The two-dimensional model of the igneous formation is refined, and theoretical derivations are made, including the linear elasticity principal equation and the extent of the plastic zone within the wellbore. A numerical simulation model is developed using ABAQUS to analyze the wellbore stability of the weak interlayer igneous formation, accounting for drilling fluid immersion and weak interlayer conditions. The numerical simulations focus on four key aspects of the weak interlayer formation: strength, permeability, horizontal in-situ stress anisotropy, and abnormal pore pressure. The study findings indicate that strengthening the weak interlayer effectively mitigates the risk of wellbore instability. Moreover, the permeability of the weak interlayer exhibits minimal impact on wellbore stability within the formation. However, an increase in horizontal in-situ stress anisotropy and the abnormal pore pressure both decrease wellbore stability along the direction of the maximum in-situ stress. [ABSTRACT FROM AUTHOR]

The X oilfield is the first sandstone reservoir under the influence of igneous rock, which is discovered and put into development in Bohai Sea. Compared with the conventional sandstone reservoir, the oilfield is affected by magmatic activity, the reservoir heterogeneity is serious and the micro pore structure is complex, which results in the poor correlation between mobility calculated by traditional methods and specific oil production index. In order to predict oil well productivity and guide oilfield well location deployment, the quantitative transformation of sandstone reservoir affected by igneous rock is studied in this paper. According to the distribution mode of igneous rock in the reservoir, a permeability model of quantitative characterization for sandstone reservoir permeability is established, in which the influences of heat conduction, reservoir skeleton deformation and stress sensitivity are considered, and then the igneous rock influence on the ground temperature field of surrounding rock is simulated by ANSYS software. According to the relationship between porosity and permeability, the quantitative transformation effect of igneous rock thermal effect on sandstone reservoir is quantitatively characterized. The reservoir temperature field variation law, different baking types and igneous rock thickness influence on the transformation degree of sandstone reservoir are analyzed. Finally, the X oilfield is taken as an example to verify the research method, and the second batch of wells location deployment is successfully guided. The results show that the thermal effect of igneous rock reduces the permeability of reservoir, and the temperature of reservoir increases first and then decreases with time, the rising speed is faster than the falling speed, with the increase in distance from igneous rock, the maximum temperature of reservoir shows a downward trend, in the case of baking on both sides, the heat of igneous rock is greater, which makes the temperature of surrounding reservoir rise more, and the transformation effect on reservoir is more obvious. The influence range of igneous rock thickness on permeability is basically the same, but with the increase in thickness, igneous rock has a greater influence on surrounding rock. The research example of the X oilfield shows that the existence of igneous rock reduces the reservoir physical properties of development wells by 1.2–5.9 times. The correlation between igneous rock physical properties and specific oil production index corrected by this method can reach 0.9478. By avoiding igneous rock, the comparative production of the second batch of development wells is 1.5 times that of the first batch of development wells. [ABSTRACT FROM AUTHOR]

Pumice is a low‐density, light‐coloured volcanic rock (igneous rock) formed when the magma from a volcanic eruption is suddenly cooled. It has a porous structure and can be different colours and have different densities. Pumice stone, unlike other rock, does not sink in water because it has a low density. In the present study, the thermoluminescent (TL) dosimetric characteristics, such as the dose–response, TL signal fading as a function of storage time, heating rate, and reusability of pumice collected on the Mediterranean coast were investigated. From this study, it was concluded that the pumice stone showed TL properties with a TL glow curve including an obviously wide peak at ∼200°C. A wide linear dose–response region up to 144 Gy, low fading of the TL signal when it was kept in a dark room for a long time, and poor reusability properties were observed for dosimetry use. [ABSTRACT FROM AUTHOR]

The Early Paleozoic tectonic evolution of the South China Block (SCB) remains controversial related to intracontinental orogenic and oceanic subduction processes. We present whole-rock major and trace elemental data, LA-ICP-MS zircon U-Pb age and Lu-Hf isotopic data for the Early Paleozoic igneous rocks including granodiorites from the Yuechengling pluton and volcanic breccias from the Damingshan pluton from the western segment of the Jiangnan Orogen in the SCB. LA-ICP-MS zircon U-Pb dating yielded emplacement ages for the Yuechengling S-type granitoids of 438–436 Ma and the deposited age for the Damingshan volcaniclastic rocks to be later than 451 Ma. The Yuechengling granitoids have consistent SiO2, TiO2, Fe2O3T, MgO, and P2O5 contents, higher Al2O3 contents, and Na2O + K2O values, but lower Mg# values, compared with those of the Damingshan volcaniclastic rocks. All the studied samples exhibit enrichment in LREEs and moderate negative Eu anomalies (δEu = 0.63–0.75), with negative Ba, Sr, Nb, Ta, P, and Ti anomalies, and positive Rb, Th, U, Pb, and K anomalies. The granitoids have variable CaO/Na2O ratios of 0.22–1.11, negative εHf(t) values of −11.98 to −0.90, and corresponding TDM2 ages distributed from 2.37 to 1.55 Ga. The petrographic and geochemical characteristics of the Yuechengling granitoids indicate that their parental magma was derived from a crustal meta-greywacke and meta-pelite components in the Paleoproterozoic basement, and have undergone some degree of fractional crystallization. The volcaniclastic rocks have mostly negative εHf(t) values with partially positive (−27.54 to 8.73), and zircons with negative εHf(t) values (−27.54 to −0.14) show TDM2 ages of 3.79 to 1.63 Ga. Combined with petrographic and geochemical data, we suggest that the Damingshan volcaniclastic rocks were derived from Neoarchean-Neoproterozoic crustal materials and the felsic parental magma has undergone some degree of magma mixing with mantle material, and deposited soon after a Late Ordovician volcanic eruption (later than 451 Ma). Integrated with previous studies, our new data support the intracontinental orogenic model to account for the Early Paleozoic tectonic evolution. Thus, we suggest that the Early Paleozoic tectonic setting of the SCB was intracontinental orogeny rather than oceanic subduction-collision.

In order to investigate the influence of igneous rock powder and silica fume on the performance of cement mortar, facilitate the application of igneous rock powder in engineering, and promote the greening of the cement industry, this study examined the pozzolanic activity of three different types of igneous rock powders: granite, andesite, and tuff. It explored the workability and mechanical properties of both binary systems (igneous rock–cement) and ternary systems (igneous rock–silica fume–cement). Microscopic techniques including X-ray diffraction (XRD), thermogravimetric analysis–differential thermal analysis (TG-DTA), scanning electron microscopy (SEM), and nitrogen adsorption were used to investigate the mechanisms of how different types of igneous rock and silica fume affect the cementitious systems. The results showed that the pozzolanic activity of igneous rock powders was relatively weak, and their inclusion at levels below 20% had minimal impact on the flowability of cement mortar. In fact, within the 20% inclusion range, andesite powder even increased the flowability. Co-blending igneous rock powders with silica fume promoted the early hydration of cement, resulting in reduced calcium hydroxide (CH) content in the hydration products. The most significant increase in strength of the cement mortar system was observed when 5% to 10% (by mass) of igneous rock powder and 5% to 10% of silica fume were used as replacements for cement. The highest cement mortar strength was achieved when 10% andesite and 10% silica fume were used as replacements, resulting in a compressive strength of 52.2 MPa.

In order to study the effect of igneous rock intrusion on coal oxidation, the electronic scanning mirror, specific surface area tester and pressure mercury meter are used to test the coal samples before and after the igneous rock intrusion, by comparing and analyzing the scanning electron microscope, specific surface area and pore volume of coal samples before and after igneous rock intrusion, the changes of microstructure and porosity of coal samples before and after igneous rock intrusion are studied. The results show that the pore structure of the coal sample changes after the igneous rock intrusion, the porosity increases, and the oxygen adsorption ability is enhanced; the change of coal molecular structure leads to the oxidation of metamorphic coal after igneous rock intrusion, and the greater the metamorphic degree, the easier the oxidation.

• The reactivity of basalt from Poland in CO 2 -water-basalt system was carried out. • An experiment on geochemical reactor was carried out for 65 days at 293 K and 0.43 MPa. • Partial dissolution and conversion of minerals was achieved. • Tight intrapore transport pathways have been clogged with secondary minerals. • A transformation of the macroporosity and morphology of the sample was achieved. The aim of the work was to identify the basic structural properties of basalts from the Central European Volcanic Province in Poland in the context of assessing the possibility of permanent CO 2 storage. The research was carried out on rock samples from three Polish basalt mines. An experiment on the reactivity of minerals contained in basalt was carried out in the original geochemical reactor. In an isolated system with a capacity of 100 cm3, proper analyzes of mineral carbonation were carried out for 65 days at a temperature of 293 K and a pressure of 0.43 MP. The pressure, pH and temperature of the process were recorded. The mechanism of structural changes that occurred in pores of different diameters was determined. SEM microscopic analyzes showed a transformation of the macroporosity and morphology of the sample. The formation of new voids and transport channels was observed, which resulted from the partial dissolution and conversion of minerals. At the same time, the pore surface area in the transitional pores and finest micropores has been reduced, indicating that the surface area of these pores have been overbuilt and the tight intrapore transport pathways have been clogged. The gravimetric measurements of the sorption capacity of basalt in relation to gaseous CO 2 were also conducted. After the mineral carbonation process, the efficiency of CO 2 accumulation decreased, which confirmed that the previously free pore space had been filled. Comprehensive scanning, structural and sorption studies confirmed the migration and multi-track transformation of minerals from basalt. [ABSTRACT FROM AUTHOR]

Desa Siron Krueng merupakan salah satu desa yang berada pada Kecamatan Kuta Cot Glie, Kabupaten Aceh Besar, Provinsi Aceh. Formasi yang terdapat pada lokasi penelitian terdiri dari Formasi Seulimeum (Qtps), Formasi Komplek Indrapuri (Tuic), Formasi Meucampli (Tlm) dan sedikit Formasi Batugamping raba anggota terumbu (Murlr). Metode yang digunakan pada penelitian ini berupa pemetaan geologi dan analisis petrografi (thin section) pada batuan beku. Tujuan penelitian ini yaitu untuk melihat kondisi litologi di lokasi penelitian, dan menginterpretasi sayatan tipis batuan yang berguna untuk melihat kandungan mineral dan untuk mengetahui petrogenesis batuan beku yang terdapat pada lokasi penelitian. Berdasarkan hasil penelitian yang telah dilakukan, litologi yang terdapat pada lokasi penelitian terdiri dari 3 satuan batuan yaitu satuan batupasir tufaan, satuan serpentinit, dan satuan andesit. Pada hasil analisis petrografi, mineral yang terdapat pada batuan beku di lokasi penelitian terdiri dari ; kuarsa, piroksen, hornblende, plagioklas, olivin, opak, dan gelasan. Petrogenesis batuan beku di lokasi penelitian terdiri dari batuan beku intermediet dengan jenis magma pada batuan yang bersifat basa dan termasuk kedalam jenis batuan beku vulkanik, serta batuan beku ultramafik dengan jenis magma pada batuan yang bersifat ultrabasa dan merupakan jenis batuan beku plutonik

The search for higher yields, lower production costs, and increased sustainability in agriculture implies optimizing crop nutritional management. In this sense, basalt dust has shown potential to improve soil fertility and crop nutrition. Thus, the goal was to evaluate the potential use of basalt dust in a controlled environment. First, an experiment was carried out on soils with contrasting textures (sandy and medium) under a random design, with four replications. These soils were incubated with basalt dust doses for 90 days, and later analyzed for chemical properties. Then, after soil incubation, four experiments were carried out in a pot system, where maize and bean plants were grown, with four replications. Plant shoots were evaluated for dry weight and macro- and micronutrient accumulations. The results of the incubation test showed that basalt dust increased available phosphorus, potassium, calcium, and magnesium levels in the soil about twenty, ten, fifteen, and thirteen times higher than those without the basalt dust, respectively. Maize and bean plants grown in soils enriched with basalt dust showed macro and micronutrient accumulations, up to five times higher than plants without the use of basalt dust. These results showed the usefulness of basalt dust in aiding nutritional management in agriculture.

Aiming at the problem of low efficiency of breaking Igneous rock, the models of breaking Igneous rock under cut-impact loads by spherical cutter, wedge cutter, and conical cutter were established respectively based on rock mechanics and finite element theory, and the Igneous rock breaking processes of three types of cutter under different combinations of impact parameters are simulated. The variation curves with impact parameters of Igneous rock breaking depth and volume, mechanical specific energy, and average tangential force of cutters are subsequently obtained, and the influence of cutter types, impact frequency, impact force on rock breaking efficiency were analyzed. Moreover, the mechanical properties of the cores collected from Hashan block and Mulei block in Junggar basin are analyzed by expariments under the condition of confining pressure. When the confining pressure reaches 60 MPa, the compressive strength of HS-3 and ML-3 rock samples reach 730.72 MPa and 301.75 MPa respectively. The results show that the impact resistance of spherical cutter is the best. When the weight of bit is 600 N and cutting speed is 1000 mm/s, the rock breaking efficiency of spherical cutter is the lowest, followed by conical cutter, and the wedge cutter is the highest. The drilling bit used in breaking Igneous rock under cut-impact loads should be a combination of these three types of cutters, which could improve the rock breaking efficiency by impact operation, and ensure the service life of bit. The results could provide basis for the design of drill bit and the parameters selection of impact tools for Igneous rock. [ABSTRACT FROM AUTHOR]

With the hypothesis that the use of rock dust is an economically viable alternative for supplementary fertilization in the soybean crop in the region of Dourados, Mato Grosso do Sul (MS), this study evaluated the use of rock dust in the soybean crop, taking into account the relationship between productivity and cost of production. The experiment was installed with the application of rock dust (0, 2.5, 5.0, 7.5, and 10 Mg ha-1) in soybean cultivation. Productivity, production cost, and economic viability indicators were monitored and calculated. Results showed that the application of rock dust positively influenced the total revenue, as well as the gross margin and net margin of the treatments, allowing a higher rate of return on the producer's investments. With the application of doses greater than 2.5 Mg ha-1 of rock dust, a higher total revenue could be obtained, however, there was a lower value of gross margin, net margin, leveling price, and leveling point components. Therefore, conclude that the application of up to 2.5 Mg ha-1 is a viable alternative to increase soybean profitability in the region of Dourados/MS. Keywords: productivity, fertilizers, igneous rock, economic indicators. [ABSTRACT FROM AUTHOR]

The reservoirs in the eastern depression of Liaohe basin are formed by multistage igneous eruption. The lithofacies and lithology are complex, and the lithology is mainly intermediate and basic igneous rocks. Based on the integration of debris data of igneous rocks and logging data, this article selected 6,462 continuous logging data with complete cuttings data and five conventional logging curves (RLLD, AC, DEN, GR, and CNL) from four wells in the eastern depression of Liaohe basin as the training set. A variety of lithologic identification schemes based on support vector machine and random forest are established to classify the pure igneous strata and actual strata. By comparing the classification results with the identification data of core slice and debris slice, a practical lithologic classification scheme for igneous rocks in the eastern depression of Liaohe basin is obtained, and the classification accuracy reaches 97.46%.

Wellbores drilled in igneous formation with weak interlayers face significant risk of instabilities. This study aims to investigate the underlying mechanisms of these instabilities by employing a combination of rock mechanics tests and numerical simulation techniques. The mechanical properties of igneous rocks are evaluated to determine core strength parameters and analyze the impact of drilling fluid immersion on core strength. The two-dimensional model of the igneous formation is refined, and theoretical derivations are made, including the linear elasticity principal equation and the extent of the plastic zone within the wellbore. A numerical simulation model is developed using ABAQUS to analyze the wellbore stability of the weak interlayer igneous formation, accounting for drilling fluid immersion and weak interlayer conditions. The numerical simulations focus on four key aspects of the weak interlayer formation: strength, permeability, horizontal in-situ stress anisotropy, and abnormal pore pressure. The study findings indicate that strengthening the weak interlayer effectively mitigates the risk of wellbore instability. Moreover, the permeability of the weak interlayer exhibits minimal impact on wellbore stability within the formation. However, an increase in horizontal in-situ stress anisotropy and the abnormal pore pressure both decrease wellbore stability along the direction of the maximum in-situ stress.

This study investigates the water saturation effects on the dynamic compressive strength and fragmentation behavior of Indian gabbronorite. A selection of gabbronorite was divided into specimens that were either saturated in distilled water for 120 days or dried in a vacuum oven at 105 ∘ C. The specimens were then compressed to failure at a strain rate on the order of 10 2 s - 1 using a Kolsky (split-Hopkinson) bar and compared with quasi-static results. The dynamically compressed oven-dried gabbronorite exhibited a 64 % increase in ultimate compressive strength compared to identical specimens compressed quasi-statically, while dynamically loaded saturated specimens exhibited a 77 % increase compared with those tested quasi-statically. Under dynamic conditions, saturated specimens exhibited a 27 % reduction in ultimate compressive strength compared to dried gabbronorite under the same loading conditions. Under quasi-static conditions, saturated gabbronorite exhibited 32 % lower compressive strength than equivalently loaded dry specimens. After compression, the resulting fragments were collected and measured for their characteristic length and size distributions. Saturated gabbronorite produced fewer fragments smaller than 200 μ m when compared to dry specimens under equivalent dynamic loading conditions. Finally, fragments of both saturated and dried specimens were found to follow log-normal size distributions. Highlights: Water saturation effects on the strength and fragmentation behavior of gabbronorite under quasi-static and dynamic compression was explored. Ultimate compressive strength in gabbronorite increased under dynamic conditions and was more pronounced in saturated specimens. Saturated gabbronorite produced fewer, smaller fragments than dried, and both had fragment sizes that nominally followed log-normal distributions. [ABSTRACT FROM AUTHOR]

The pore structure of rock changes significantly during the heat treatment process, which affects the internal emission rate of radon. This study introduces the results of radon emission rate of rock after high temperature and analyzes the effect of the pore structure in rock mass on radon emission. The results show that there is a good positive correlation between temperature and radon emission in rock mass within a certain temperature range, and the higher the temperature, the higher the radon concentration emission. Two igneous rocks have the rate which is highest after the treatment in 400 °C. The absorption and sealing of radon in the microcapillary are the main occurrences of radon in rock mass. This is reflected in the increase in microcapillary porosity and the decrease in DP, which changes the microstructure of the rock and increases the connectivity of the internal pore channels of the rock, thereby increasing the volume and length of the migration channels for radon. These results are helpful to understand the influencing mechanism of radon emission process in rocks. [ABSTRACT FROM AUTHOR]

The use of igneous rock nano-powder as a heterogeneous and recyclable multi-oxide nano-catalyst synthesizing of 5-substituted-1H-tetrazoles is reported. The igneous rock nano-powder was initially prepared by using the ball-milling method. Then, the structure, morphology, and magnetic properties of the prepared igneous rock nano-powder were characterized with some different spectroscopic, microscopic, and thermogravimetric techniques, such as FTIR, FESEM, XRF, XRD, Histogram, and EDS. The instrumental analyses showed that the prepared igneous rock powder is a mixture of metal oxides, such as Si, Al, Ca, Mg, Fe, Na, Mn, and Sr. It showed an excellent catalytic performance in synthesizing of 5-substituted-1H-tetrazoles through [3 + 2] cycloaddition reaction between sodium azide and nitrile compounds. Various aliphatic and aromatic nitriles and sodium azide were reacted in the presence of a catalytic amount of igneous rock nano-powder at 80 o C temperature in PEG-400. The protocol was simple and rapid, with suitable yields of the obtained tetrazoles. The igneous rock nano-powder is readily accessible, reusable, and holds potential for further application in acid-catalyzed organic syntheses and industrial requirements. [ABSTRACT FROM AUTHOR]

The main purpose of this study is to investigate the relationship between unit side resistance (USR) and uniaxial compressive strength (UCS) of vesicular and massive basalt stone in Gaziantep and surrounding provinces. The results obtained from the experiments were shown using linear and non-linear methods and compared with the literature. The UCS test results of the massive basalt stone were two times higher than the ventilated ones. It should also be noted that the unit side resistance of Gaziantep massive basalt stone was found to be lower than the vesicular basalt stone. Consequently, the linear correlation and non-linear correlation ranges have also been proposed to estimate the USR of such basalt stone. Using the equations developed in this study, designers will be able to quickly calculate the friction force based on the USC test results. In addition, designers will not over-design depending on the results obtained from the vesicular basalt areas. [ABSTRACT FROM AUTHOR]

Hydrothermal fluid is one of the factors controlling Archean buried hill reservoirs in Bozhong 19-6. However, there are no clear studies focusing on the influence of hydrothermal alteration products and their lithological characteristics on reservoirs. Through characterization of the alteration reservoir and construction of a new subtraction model of the logging-rock mechanical alteration degree, the comprehensive uses of core, thin section, and electrical imaging logging data are considered as the research objects with metamorphic and igneous rocks. Thus, the relationship between lithologies with different alteration degrees and reservoir quality is revealed. The study shows that feldspar chloritization and sericitization are the main factors controlling the hydrothermal alteration of the reservoir; the overall alteration degree of igneous rocks is high, and the overall alteration degree of metamorphic rocks is low; the reservoir with strongly altered igneous facies is prone to forming dissolution pores, with strong reservoir inhomogeneity and poor reservoir performance (alteration degree is greater than 15%); the reservoir with weakly altered metamorphic facies is prone to developing fractures and a high reservoir productivity (alteration degree is 0); The reservoirs with altered metamorphic facies are numerous in the formation, spatially diverse in type, and second in reservoir quality only to those in the weakly altered metamorphic facies (alteration degree of 0–15%). This method is expected to provide a reference for quickly finding advantageous reservoirs in the Bohai Sag.

Downhole drill string vibration data can provide an effective reference for research drill string vibration during drilling. In this paper, the research group used a storage-type downhole vibration measurement equipment equipped with an orthogonal, three-axis accelerometer to measure and collect drill string vibration signals during drilling in an oil well. Based on the installation characteristics of the sensor, the relationship between the acceleration measurement value of the sensor and the center acceleration value of the drill string is obtained. Then the time-domain signals representative of the vibration in igneous rock drilling is analyzed. It can be found that the occurrence of stick-slip vibration can be judged by the regular wave packets in the time-domain signal, while the time-domain signal of whirl is disorderly. The main frequency of stick-slip vibration in the low-frequency band is 0.1221 Hz and the period of stick-slip vibration is very close to 10 s through Fast Fourier (FFT) and Short-time Fourier transform (DTFT) methods. In the process of whirling, two frequencies, respectively, 0.05341 Hz and 155.5 Hz, play a major role. The frequency 0.05341 Hz is very close to the reciprocal of the period of 20 s when the peak energy spectrum density appears, indicating that the occurrence of whirl is very likely to be related to the natural frequency of the drilling tool. Through further time-frequency analysis, it also can be found that the occurrence of whirl and stick-slip is greatly related to the use of torsional impactors and jars. [ABSTRACT FROM AUTHOR]

This research is aimed at knowing morphology characteristics and factors which influence landform that is located at Rewata’a Coastal. Geomorphology is a study stressed on landform characteristics with all processes and material at the world surface. The landform is seen as the appearance of landform as the main aspect of the landscape. The method used in this research is a qualitative descriptive method by collecting primary data, such as images or photos of land from that is directly taken from the research location. The phenomenological approach used to explain what, where, how, and why related to landform which based on available theory and prior research. The research result concludes that the Rewata’a Village morphology is cliffed coast, namely the coastal with the vertical cliff. Composed by host rock or hard sediment. Although we can find sand land at bay and north area. The landform found are delta, sea cave, beach, spit, notch, cliff, wave-cut platform, and stack.

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Large areas of Yanshan period granites with high heat production values (3–10 μW/m3) and mantle plume around Hainan province co-exist in Igneous Rocks Regions of South China (IRRSC). Surface manifestations are mainly warm/hot springs with temperatures below 90 °C and no typical phenomenon of high temperature resources have been observed. The main objective of this paper is to discuss the existence of high temperature geothermal resources and their possible locations under this kind of geothermal and tectonic background by analysis of high temperature heat sources, borehole temperature measurement, and reservoir temperature estimation. Two possible partial melts of the magma chamber were detected as high temperature heat sources in the Southern Leizhou Peninsular and North Hainan Island at a depth of 8–15 km. Other low resistivity zones in the upper crust are more likely caused by fluid in the formations or faults but not high temperature heat sources. This was also verified by borehole temperature measurement in these two areas, with maximum formation temperatures of 211°C and 185°C found, respectively. Reservoir temperatures from fluid geothermometers show lower temperatures of between 110–160°C for typical geothermal fields over the IRRSC but not in the Southern Leizhou Peninsular and Northern Hainan Island. In all, high temperature geothermal resources may be found in the Southern Leizhou Peninsular and on Northern Hainan Island.

The studies regarding the influence of stone-extracted materials on the mechanical properties of Portland cement mortars, has a growing interest in Mexico due to its geological diversity. This is of great relevance since, according to the mechanical properties, a suitable use of mortars can be proposed to satisfy specific requirements of regional construction systems. For this reason, the main goal of this research is to relate the composition of three types of aggregates commonly used in construction practices in two geologically different regions in Mexico with the mortar's compressive strength. Composition is analyzed by mineral crystalline phase identification. The analytical techniques employed were: Petrography, Qualitative X-ray Powder Diffraction, Scanning Electron Microscopy Energy-dispersive X-ray spectroscopy (EDS). The results obtained showed that sands with same origin sands (igneous sands) can provide very different compressive strength values; while aggregates from different origin (igneous and sedimentary) can have similar behavior regarding compressive strength. The amorphous fraction of the pink sand aggregate was attributed as the main factor regarding the change in mechanical properties. The gray igneous sand is adequate for a type N mortar, while the pink igneous sand and the rock limestone powder provide type M mortars.

Abstract A well‐ordered polygonal crack pattern is frequently observed on the outcrop surface of columnar joints. The crack pattern's geometry and topology result from the volume contraction of solidified lava during thermal dissipation. In this study, we conducted field measurements of columnar joints at four different sites with various lithologies in Japan to understand the influence of geography and lithological character on their geometric characteristics. Drone‐aided photography and computer‐based image analysis enabled us to examine the constituent polygons' geometric attributes and their statistics with high accuracy. This methodology revealed a relationship between the geometry and topology of the polygonal crack patterns. Moreover, we established a positive correlation between the polygon area and the number of vertices of a polygon at each study site, irrespective of lithology, or geographic position. These results are consistent with previous investigational studies, in particular starch‐based analog experiments.

A well‐ordered polygonal crack pattern is frequently observed on the outcrop surface of columnar joints. The crack pattern's geometry and topology result from the volume contraction of solidified lava during thermal dissipation. In this study, we conducted field measurements of columnar joints at four different sites with various lithologies in Japan to understand the influence of geography and lithological character on their geometric characteristics. Drone‐aided photography and computer‐based image analysis enabled us to examine the constituent polygons' geometric attributes and their statistics with high accuracy. This methodology revealed a relationship between the geometry and topology of the polygonal crack patterns. Moreover, we established a positive correlation between the polygon area and the number of vertices of a polygon at each study site, irrespective of lithology, or geographic position. These results are consistent with previous investigational studies, in particular starch‐based analog experiments. Plain Language Summary: "Gallery of rock prisms carved by Nature" When erupted lava is rapidly cooled by seawater, numerous cracks penetrate inward, resulting in a splendid landscape called "columnar jointing." It is a mysterious aggregate of prismatic rocks with polygonal (often hexagonal) cross‐sections, the most famous example being Giant's Causeway in Ireland. Careful examination of columnar jointing over several localities has revealed several scientific laws hidden behind these joints' shapes. First, there is a relationship between the type of polygon in the cross‐section and its area. When the area is small, the shape tends to be a pentagon; but if the area is medium or large, the shape is likely to be a hexagon or heptagon, respectively. Interestingly, this tendency holds regardless of the rocks' locality, chemical character, or the prism's length scale. Second, the extent to which the polygons shape is distorted is not random but is kept below a threshold. Again, this threshold's magnitude is universal and independent of the locality, character, and prism scale. These two findings imply an unknown mechanism governing how Nature carves these magnificent prismatic sculptures during the rapid cooling of lava. Key Points: A drone was used to obtain aerial images of polygon patterns on columnar joints' outcrop surfaces at four different sites in JapanUnexpected correlations between geometrical characteristics of the cross‐section of prisms were revealed by image processingConclusions obtained from field measurements were consistent with those of analog experiments based on starch slurry [ABSTRACT FROM AUTHOR]

Copyright of Oil Drilling & Production Technology / Shiyou Zuancai Gongyi is the property of Shiyou Zuancai Gongyi Bianjibu 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.)