Deposition Of Rocks Research Articles

Late Campanian Climatic-Continental Weathering Assessment and Its Influence on Source Rocks Deposition in Southern Tethys, Egypt

Climatic variability and silicate weathering are remarkable features throughout the Late Cretaceous period. Late Campanian black shale is considered the most significant silicate source rock in the southern Tethys. Here, we used mineralogical and geochemical data to evaluate the continental weathering intensity and climatic changes as well as their impact on the deposition of the Late Campanian black shale in the Western Desert of Egypt. The studied black shale has a relatively high concentration of Al, Fe, Mg, Ca, Sr, Ga, Co, Cr, and V when compared to the average Post-Archean Australian Shales (PAAS). The studied samples have elevated values of Ga/Rb, and low values of Rb/Sr, Sr/Cu, and K2O/Al2O3, supporting the deposition of Late Campanian shale under warm/humid conditions. Furthermore, the average chemical index of alteration (CIA, 78.6%), chemical index of weathering (CIW; 83.8%), C-value (1.26), Fe/Mn (408), and Mg/Ca (1.54) reveal the predominance of warm/humid climate. The chemical weathering proxies (CIA, CIW, PIA, LnAl2O3/Na2O) and ACNK diagram imply that the Late Campanian samples were exposed to a moderate grade of chemical alteration. The deposition of black shale occurred under high seawater salinity conditions based on Sr/Ba (Avg = 3.6). Additionally, the weathering indices are well correlated with paleoclimatic proxies, suggesting that weathering intensity is strongly affected by paleoclimate. However, chemical weathering during the Late Campanian has a weak influence on oceanic nutrient fluxes. No substantial impact of the paleoclimate during the deposition of Late Campanian black shale on water salinity was reported.

Prospects of the oil and gas potential of the pre-Jurassic deposits of Southern Mangistau, the direction of further prospecting and exploration, and some issues of the methodology of their implementation

In this paper, the authors present the features of the geological structure of the pre-Jurassic rock deposits of the Mangyshlak oil and gas complex. A brief analysis of the identified objects is given, prospects are determined, and proposals are given for the further direction of setting up prospecting and exploration work for oil and gas.

Using Maxwell’s Theory to model and quantify the fracture evolution of cyclothymic deposition phosphate rock

The evolution and stability of fracturing in the cyclothymic deposition of phosphate rocks are strongly affected by the viscoelasticity and structural form of the rock-forming minerals. Presently, there is no standardized method that has been widely accepted to accurately quantify the elastic-plastic deformation and fracturing of such striped structural rock nor reflect the role of the different lithogenous minerals in phosphate rocks when subjected to viscoelastic strain loading. In this study, integrated mathematical equations were formulated for modelling the mechanical and fracture behaviour of cyclothymic deposition in structured phosphate rocks. These constitutive equations were developed based on Maxwell’s Theory after the elastic modulus and damping coefficient of the rock-forming mineral from the mechanical testing were substituted into the derived-equations. In these new models, the apatite stripes and dolomite stripes were incorporated into the transverse isotropic model through the analysis of structural characteristics of the phosphate rock. Through experimental validation, the response curves of the creep and stress relaxation tests were found to be consistent with the deformation curves generated by modelling using the mathematical equations. Overall, the formulated model along with the corresponding equations was found to exhibit good applicability properties to describe phosphate’s mechanical and fracture behaviour under low horizontal compressive stresses. In the study, the creep mechanism in phosphate rocks were satisfactorily analysed from the angles of microscopic morphology, cracks evolution, and inter-crystalline strength. The hard brittle apatite was found to be surrounded and separated by high creep variant dolomite. Furthermore, the analysis showed that dolomite crystals possessing high creep properties dominated the distribution and evolution of secondary structures in the phosphate rock, under the condition of long-term low-stress loading.

Paleo-sedimentary environment and lithofacies of Jurassic Da’anzhai Member in the Central Sichuan Basin-A case study of Well Ren’an 1

The Jurassic Da’anzhai Member in Sichuan Basin is an important target for shale oil exploration. Whole rock X-ray diffraction analysis, thin section, SEM and TOC testing, as well as major and trace element analysis are used to analyze the relationship of lithofacies and pore types with the sedimentary environment of the Da’anzhai Member in the Central Sichuan Basin. The results show the Da’anzhai Member in the Well Ren’an 1 (RA1) is divided into six types of lithofacies, based on a three-level division method of mineral composition-TOC-mineral structure— namely, massive mud-bearing shell limestone lithofacies (F), thick argillaceous shell limestone lithofacies (E), laminated clay silt shale lithofacies (D), thin shell calcareous shale lithofacies (C), laminated shell-bearing shale lithofacies (B), and thick clay shale lithofacies (A). The pore spaces include intergranular pores, intergranular dissolution pores, authigenic calcite intergranular pores, authigenic quartz intercrystalline pores, intergranular pores of clay minerals or pyrite nodules, as well as organic pores. The Da’anzhai Member was deposited in a semi-deep to shallow lake sedimentary environment, with relatively low salinity. This strata experienced moderate-to-strong chemical weathering as a result of the semi-arid, warm and humid paleoclimate environmental conditions that persisted during its deposition; low weathering and dry paleoclimate conditions occurred periodically. Paleoenvironment is an important influence on the lithofacies and pore types of the Da’anzhai Member. The persistence of arid climate conditions contributed to a decline in water depth, relatively high salinity, low organic productivity, and the deposition of carbonate rocks that characterize lithofacies E and F; mostly intercrystalline pores formed in these lithofacies in response to the prevailing arid climate conditions. Conversely, warm, and humid climate conditions increased the inflow of fresh water, terrigenous debris, and nutrients into the lacustrine basin that led to the deposition of fine-grained sedimentary rocks of lithofacies A, B, and C. These lithofacies are characterized by abundant nano pores, such as clay intercrystalline pores and organic pores.

Filizchay pyrite-polymetallic deposit (the southern slope of the Greater Caucasus) – as a typical representative of the SEDEX type pyrite deposits


 
 
 The article has been devoted to one of the largest deposits of the southern slope of the Greater Caucasus – the Filizchay pyrite-polymetallic deposit. It has been found that the main morphology peculiarity of the pyrite-polymetallic deposit of the Filizchay deposit is that it is a single, compact sheet-like body composed mainly (at 90-95%) by the aggregates of the sulfide ores which are based on pyrite, sphalerite, galena and to a far lesser extent chalcopyrite and pyrrhotite. The carbonate minerals played a subordinate role in the deposit composition and quartz, sericite and chlorite – even less. The pyrite –polymetalic ores of the deposit are characterized by the following main mineralogical-textural varieties of ores: layered-bedded pyrite-polymetallic, massive sulfur-pyrite, massive pyrite-polymetallic, spotted-disseminated pyrite-polymetallic and vein-disseminated pyrite-polymetallic. The vein-disseminated ores are adjacent to the deposit on the footwall and are considered as independent bodies. Two industrial-techno- logical types of ores, oxidized and pyrite-polymetallic, have been distinguished at the deposit. The latter is in turn divided into two grades: mixed and primary ores. These three varieties of ores differ in the content of the oxidized lead forms. The ores with a content of the oxidized lead speciation above 60% have been classed as oxidized ores, those from 20% to 60% as mixed and those below 20% as primary. The Filizchay deposit consists of thin-bedded massive sulfides with shales, siltstones or sandstones interbeds («ore flysch») which have been formed exclusively or mainly as a result of the exhalative processes on the seabed and differ from massive sulfide deposits in volcanic rocks. On the basis of this and also according to the geological structure, the reserves of the valuable Zn + Pb components of the deposit belong to the SEDEX type that is the most important source of lead, zinc and silver. The deposit had been developing for a long time starting from the period of sedimentation and up to the ore’s formation of the copper-pyrrhotite stage. The lower age limit of the mineralization is determined by the presence of the hydrothermal-sedimentary ores of the Upper Pliensbachian. The upper age limit is established by the presence of the pebbles of the hydrothermally altered rocks and by their sulfide ores in the conglomerates underlying the deposits of the lower parts of the Upper Jurassic.
 
 

Giant Mesozoic gold ores derived from subducted oceanic slab and overlying sediments

Orogenic gold deposits account for more than 30 % of the global gold resources. To understand the genesis of orogenic gold deposits and ultimately target new orogenic gold deposits, it is important to determine the origin of gold. However, there has been a continuing debate surrounding gold source reservoirs. The Jiaodong gold province, comprising ore hosted within Mesozoic granitoids that intruded Archean metamorphic rocks, together with other gold occurrences in the North China block, collectively constitute the only Mesozoic world-class gold resource in a Precambrian basement. This geological setting, with young deposits in ancient rocks, offers a great opportunity to better determine the gold source because it allows us to fingerprint the isotopically distinct reservoirs. Specifically, it is possible to determine whether the mass-independent isotopic fractionation sulfur (MIF-S)-bearing Archean supracrustal rocks that form the lower crust are a permissive source. We present multiple sulfur isotope (δ34S and Δ33S) measurements of pyrite grains (n = 161) from 18 gold deposits in the six main districts of the Mesozoic Jiaodong gold province. Gold-associated pyrite grains yield non-MIF-S signatures (Δ33S = 0 ‰), indicating that Archean metasedimentary rocks are not a source reservoir of sulfur and gold. The isotopically heavy S (average δ34S = +9.0 ± 3.7 ‰, 2SD) demonstrates a sulfur contribution from a subducted oceanic slab and, in particular, its overlying sediments while excluding mantle and magmatic sources. The subduction-related metamorphism released appreciable gold and sulfur from the top of the downgoing slab into aqueous-carbonic fluids that ascended into the upper plate along crustal structures traversing a tectonically thinned crust. Here, we demonstrate that these giant Mesozoic orogenic gold deposits sourced gold and sulfur during subduction-related devolatilization reactions.

Ветровая эрозия почв в агроландшафтах на юго-востоке Томской области

Eolian processes associated with the destruction, transportation and deposition of sedimentary rock by wind develop in arid natural zones, as well as on agricultural lands. The general conditions for their development are completely absent or sparse vegetation cover, the presence of dispersed rocks and strong winds. Aeolian processes are most developed in deserts and semi-deserts, where many researchers have studied them. In the forest zone of the West Siberian Plain, these processes have been poorly studied. Researchers classify the taiga and subtaiga in the Ob and Irtysh basins either as non-deflationary or as a zone of accumulation of aeolian material. Deforestation, plowing of land, construction of various communications contribute to the development of eolian processes. Our long-term observations of eolian processes in the southeast of the subtaiga zone of the West Siberian Plain have shown that wind erosion is observed here and has focal development. The wind of the study area is characterized by gustiness, the wind speed in gusts reaches up to 20 m/s. Strong winds with a maximum speed of 25–27 m/s occur in all seasons of the year. Such winds are the most dangerous in relation to the development of wind erosion of soils on flat farmlands without forest and shrub plantations. Based on the use of natural accumulator - snow cover and atmospheric dust traps, the intensity of accumulation of eolian sediment in the snow mass and on its surface was revealed. The studies were conducted during the spring thaw for the period from 1989 to 2023. The intensity of development of wind erosion also depends on the state of the agricultural background. It has been established that up to 1000 g/m2 of eolian sediment accumulates in the plowing in the thickness of the snow on arable land, and up to 50 g/m2 in the stubble, shoots of winter, perennial grasses. During the spring melting of snow, up to 300–360 g/m2 of eolian sediment accumulates on its surface over fallow and up to 50 g/m2 over stubble and grasses. In the cedar forest, bordering on agricultural landscapes, no more than 25 g/m2 is accumulated during the specified period. The processes of blowing and accumulation of soils in agricultural landscapes are characterized by uneven development, but they contribute to the migration of matter. Dust particles are deposited in forest belts separating agricultural land. Due to this, the content of humus in the soils of forest belts is higher than on arable land and reaches up to 10 %.

3D Modeling and Estimation of the Tonnage of the Granite Quarry of Linguésso (North-West of Côte d’Ivoire) by Electrical Methods

A survey and evaluation was carried out on a potential granitoid quarry site in the locality of Linguésso (North West of Ivory Coast) with the aim of identifying and estimating the quantity of exploitable granite based on the electrical resistivity methods. The combination of electrical trailing, sounding and tomography techniques allowed the determination of the characteristics of the rock deposit, namely the electrical signature (between 19,259 Ωm and 86,316 Ωm), the extension (N90°), the rooting (between 0 and 45 m) and the fracturing (between N14° and N160°) of the granitic formation sought. The modeling resulted in an estimated mineable rock volume of 2,936,250 m3 providing a production quantity of 7,927,875 tonnes.

ПРОМИСЛОВІ ТИПИ РОДОВИЩ КАРБОНАТНОЇ СИРОВИНИ ТА ЇХНІ ПАРАМЕТРИ КОНДИЦІЙ ДЛЯ ПІДРАХУНКУ ЗАПАСІВ

The article systematizes the main industrial types of carbonate rock deposits in Ukraine and analyzes the main directions of their use. Metallurgical production and the sugar industry are identified as the main areas of use that are in short supply. Most of these explored reserves of carbonate rocks are located within the Donetsk region and the territory of Crimea. The number of explored reserves in the rest of the territory does not provide a sufficient period of operation and work of industrial enterprises for more than 10-15 years. The most effective way to provide reserves is to review the objects that are being developed today in other areas of use (except metallurgical raw materials and the sugar industry) to allocate a part of the reserves that may be suitable for these scarce areas. The analysis and systematization of the cut-off parameters for the reserves calculation of various types of carbonate rocks in accordance with their industrial types and the requirements of geological and economic evaluation were carried out. The basic parameters for the calculation of reserves are the quality indexes, which are put forward by the direction of use in the standards, the depth of the reserves calculation, the minimum thickness of the mineral from 2 m, the limitation of contours within the license area and the mining right-of-way, in the contour of the quarry at the end of the development. Parameters that take into account the risks of unconfirmed reserves associated with karst areas, high clayey rocks are almost not used, although they can be an important tool especially for operational conditions.

Inventory of Good Practices of Sustainable and Circular Phosphorus Management in the Visegrad Group (V4)

The most important raw material needed for food production is phosphorus (P), which cannot be replaced by other elements. P is listed as a Critical Raw Material (CRM) for the European Union (EU). It is an element essential for human nutrition and is used for fertiliser production. The key importance of P for human life is evidenced by the fact that if there were not enough P in fertilisers, we would only be able to feed 1/3 of the world’s population. Unfortunately, in Visegrad Group (V4) countries, Poland, Slovakia, Czech Republic, and Hungary, there is a lack of mineral deposits of phosphate rock. Therefore, there is a strong need to cover the demand for the P by importing from countries of varying stability, both economic and political, such as Russia, China, or Morocco. It is risky; if the borders for deliveries of goods are closed, it may be impossible to meet the needs of P. On the other hand, V4 countries have large secondary P resources in P-rich waste, which are lost due to P is not recovered on an industrial scale. The paper presents the importance of P raw materials in V4, the revision of primary and secondary P sources that can be used in agricultural systems, as well as the structure of import and export of P raw materials in these countries. In addition, examples of good phosphorus recovery practices in the V4 countries are presented. They include a list of initiatives dedicated to the sustainable management of P resources, and examples of P recovery projects. Implementation of P recovery for internal P-rich waste in V4 could ensure the safety of food production in this region. Such and similar initiatives may contribute to faster independence of the V4 countries from the import of P raw materials.

Assessment of the stress-strain state of pile foundations of a multi-story building with possible water saturation of loess soil

The increase in the density of buildings leads to the need to set aside for development areas that were previously considered unfavorable from the point of view of the quality of the geological conditions. Deposits of loess rocks cover almost 80% of the territory of Ukraine. Such soils are characterized by a negative feature - the ability to rapidly reduce their mechanical properties in contact with liquid and to cause additional subsidence deformations. Based on this, a significant part of buildings and structures is erected in conditions of the possible occurrence of uneven deformations due to water saturation of subsidence soils. Therefore, the foundation structures of these structures must be designed with taking into account the occurrence of subsidence of loess soils.
 In their natural state, loess soils have sufficiently high mechanical characteristics due to structural connections. However, as the moisture content increases, the resistance to compression rapidly decreases, structural bonds are destroyed, and soil subsidence is observed.
 The modern level of foundation structures design involves the search for a reliable and cost-effective foundation option. This is especially relevant in the conditions of construction on soils that have the property of settling with possible increase in moisture content.
 The paper presents the results of a comparison of foundation options, taking into account the influence of possible water saturation of loess soils on the stress-strain state of foundation structures. Different schemes of possible water saturation of loess soils were considered depending on their size and location.
 This publication is a continuation of the previously published work [4]. It was about the results of the research, which was devoted to the variant design of foundations using numerical simulation of the joint work of the elements of the "soil base - foundation - above-ground structures" system. According to the results of the study, the choice of a rational option of foundations was substantiated, based on its indicators of reliability and economic efficiency. The conducted research confirms that the size and location of the soaking zones of the subsiding soil affect the nature of the stress distribution in the foundation structures. It is shown that the variant design of foundations, taking into account the negative factors related to the soil conditions of the construction site, as well as man-made situations that may arise during the operation of the building, make it possible to design a reliable and at the same time cost-effective option of the foundations.

The ability of potassium-solubilizing fungi isolated from leucite potassium rock deposits

Abstract. Anwar AR, Ala A, Kuswinanti T, Syam’un E. 2022. The ability of potassium-solubilizing fungi isolated from leucite potassium rock deposits. Biodiversitas 23: 6579-6586. Present investigation was aimed to explore the potassium-dissolving ability of some indigenous fungi living in Indonesian leucite tuffs from volcanic rock members of Camba Formation in Barru Regency, South Sulawesi Province. There are no such findings on potassium-solubilizing fungi from South Sulawesi Province. The recent study isolated some fungi strains from the rhizosphere of vegetation found in the potassium rock deposits using Alexandrov media. A total of 22 fungal strains were isolated and tested for their ability to dissolve potassium bound to the potassium carrier minerals, qualitatively and quantitatively. Production of indole-3-acetic acid (IAA) and gibberellic acid (GA3) were also measured to test the ability of the fungus to produce growth regulator compounds. Fungal isolates with the highest dissolution index (IP) values were MgT1Pb, RgGc, PT3Pe, PT3Pa, JbT2Pa, JbT2Pd, and JbT2Pp. The highest amount of exchangeable potassium (K-exch.) was JbT2Pa with the amount of 919.8 ppm and MgT1Pb of 69.33 ppm. The isolate capable of producing the highest IAA was PsT2Pe at 6.820 ppm while the RgGd isolates resulted in the highest production of GA3 hormone at 4.116 ppm.

Sedimentary Characteristics of the Permian Zhesi Formation in Eastern Inner Mongolia, China: Implications for Sedimentary Background and Shale Gas Resource Potential.

Eastern Inner Mongolia of China is located between the Siberian plate, the North China plate, and the Pacific plate and has a complex history of tectonic and sedimentary evolution. The sedimentary strata of the Zhesi Formation in the Middle Permian recorded rich environmental, structural, and petroleum geological information, which has great significance to the Paleozoic geological research in Northeast China. Through field outcrop observation and profile measurement, combined with geochemistry, mineralogy, and the reservoir physical property test, the sedimentary environment, tectonic setting, and shale gas resource potential of the Middle Permian Zhesi Formation are analyzed. The sedimentary facies of the Zhesi Formation are distributed in strips in the northeast direction, mainly developing littoral, shallow marine, and bathyal sedimentary environments. Clastic rock deposits are mainly developed in the littoral facies, carbonate platform and tempestite deposits are mainly developed in the shallow marine facies, and mudstone mixed with turbidite deposits are mainly developed in the bathyal facies. The sedimentary environment and chronological characteristics show that the Paleo-Asian Ocean was not completely closed in the Middle Permian, and its complete closure time should be later. The characteristics of source rocks and the shale gas resource potential in the Solon area are discussed. Controlled by the sedimentary environment, the Solon area mainly deposited thick dark shale mixed with turbidite sandstone, the accumulated thickness of the dark shale is more than 200 m, with an average vitrinite reflectance (Ro) of 2.44%, and the average residual total organic carbon (TOC) content is 0.85%. The average content of brittle minerals is 60.2% and the shale foliation fracture is developed, which is easy to form natural fractures and induced fractures, so the shale has good hydrocarbon generation potential, and the generated shale gas can exist in shale in an adsorbed state and a free state. In addition, the shale gas generated in the shale can migrate to the lenticular turbidite sand body in a short distance to form free shale gas. Therefore, there is a certain shale gas resource potential in the Solon area, and finding a favorable area with high TOC is the key to future exploration of Upper Paleozoic shale gas.

New insights of the crustal structure across Estonia using satellite potential fields derived from WGM-2012 gravity data and EMAG2v3 magnetic data

Global WGM-12 gravity and EMAG2v3 magnetic models were used to present new information of the Estonian crust. The Estonian Precambrian crystalline basement, composed of Paleo-Meso Proterozoic metamorphic and igneous rocks, is covered by a Paleozoic sedimentary rock deposit 100–800 m thick. The present work aims to map structural patterns and recognise physical layers of the crust over Estonia using global potential models. The gravimetric data was used to identify the depth of the Moho and Conrad discontinuities. The magnetic data has been processed to calculate the Curie point depth (CPD), which was then used to estimate heat flow (HF) values in the study area. The depth of the Moho indicates an average value of 60 km, while the average depth of the Conrad discontinuity is around 18 Km. The depth of the CPD reveals an average value of 15 km. Different derivative techniques were applied over the residual part of both potential models, to delineate and map geophysical lineaments. The subsurface of Estonia has been divided into six petrological-structural zones: Tallinn, Alutaguse, Jõhvi, West-Estonian, Tapa and South-Estonian. Geophysical lineaments in each zone subsurface division delineates a NW-SE trend, perpendicular to the NE-SW oriented Fenno-Sarmatian collision. To visualise the anomalous crustal variations over Estonia, different profiles showing varying values of potential fields, CPD and heat flow are presented, especially around the Precambrian Rapakivi granitic plutons and in the Paldiski-Pskov deformation zone, due to the high contrast observed by mapping the different results over these areas.

Integrated bio- and chemo-stratigraphy for Early Cretaceous strata offshore Gabon: Additional constraints on the timing of salt deposition and rifting of the South Atlantic

Early Cretaceous rift basins of the incipient South Atlantic have been the focus of intense hydrocarbon exploration and production activities and host some large oil accumulations in sections predating an interval of major salt deposition, particularly in the central segment of the South Atlantic. Understanding the timing (and associated uncertainties) of source rock and reservoir deposition and their relationship with rift evolution is critical for successful exploration. However, there are still many unresolved issues and data gaps regarding the precise age and duration of salt deposition. Better chronological constraints are particularly needed to determine the timing of deposition of Pre-Salt reservoirs and the primary evaporites, as well as the secondary phase of halokinensis that resulted in variable reservoir sealing potential. To help address this gap, stable carbon isotope (δ13C) records from bulk organic matter and insoluble kerogen were generated for the Early Cretaceous salt and Pre-Salt intervals from two exploration wells offshore of Gabon. The bulk organic δ13C stratigraphies for the two wells were then integrated with palynological and ostracod biostratigraphy and placed within a sequence stratigraphic and regional tectonic framework, providing new constraints on the timing of rift lake evolution and salt deposition. The good correlation between the offshore Gabon δ13C record with other published sections calibrated to the current Geologic Time Scale as well as other regional sections from NE Brazil, supports the reliability of our new Gabon δ13C record. Several δ13C excursions are identified in the Pre-Salt sequence and are correlated with the Valanginian Weissert event and Early Aptian δ13C event(s). Salt deposition on the Gabon margin is interpreted to have occurred during an interval straddling the Early-Late Aptian boundary (∼118.4–116.8 Ma). These findings are comparable with other published estimates for salt deposition from northeast Brazil but differ from published estimates from the Campos-Santos basins; the latter are critically discussed. This study provides an important stratigraphic dataset for offshore Gabon and contributes to the ongoing debate regarding the timing of rifting and salt deposition in the Early Cretaceous of the South Atlantic passive margin system.

Provenance and metamorphism of the Mesoproterozoic Baoyintu Group: Implication for the interaction between the western Central Asian Orogenic Belt and the North China Craton

• The Baoyintu Group was the continental marginal successions deposited after the Mesoproterozoic. • The provenance of the Baoyintu Group shows an affinity with the North China Craton . • The metamorphism of the Baoyintu Group was caused by the interaction between the North China Craton and the Bainaimiao arc. The deposition and metamorphism of the sedimentary rocks are closely related to the tectonic affinity and interactions among different terranes. The metasedimentary Baoyintu Group, which is distributed in the junctional area adjacent to the Alxa Block, the North China Craton (NCC), and the Central Asian Orogenic Belt (CAOB), is an ideal objective to investigate these issues. However, its depositional age, provenance, and metamorphism have not been well studied. To solve these problems, systematic detrital zircon and rutile dating, zircon Hf isotopic analysis, and phase equilibrium modeling were conducted. The youngest detrital zircon age of 1395 ± 32 Ma constrained the maximum depositional age of the Baoyintu Group younger than the Mesoproterozoic. The detrital zircon age pattern and the Hf isotopic data indicate it possessed a similar source to the Langshan Group from the NCC but in contrast to the Alxa Group in the Alxa Block. The peak metamorphic P-T conditions of the Baoyintu Group are 650–660 °C and 12.0–13.6 kbar, which are typical in the Barrovian-type metamorphic belt. Its metamorphic age is confirmed through the rutile dating analysis, which yielded a discordia age of 384 ± 58 Ma. Our synthesized data support the presumption that the Baoyintu Group is the sedimentary series draping on the margin of the northern NCC during the Mesoproterozoic. The metamorphism is involved with the subduction or orogenic process between the NCC and the Bainaimiao arc in the CAOB during the Devonian.

Effect of structural setting of source volume on rock avalanche mobility and deposit morphology

Abstract. Deposit morphologies and sedimentary characteristics are methods for investigating rock avalanches. The characteristics of structural geology of source volume, namely the in-place rock mass structure, will influence these two deposit characteristics and rock avalanche mobility. In this study, a series of experiments were conducted by setting different initial configurations of blocks to simulate different characteristics of structural geology of source volume, specifically including the long axis of the blocks perpendicular to the strike of the inclined plate (EP), parallel to the strike of the inclined plate (LV), perpendicular to the inclined plate (LP), randomly (R) and without the blocks (NB) as a control experiment. The experimental materials comprised both cuboid blocks and granular materials to simulate large blocks and matrixes, respectively, in natural rock avalanches. The results revealed that the mobility of the mass flows was enhanced in LV, LP and R configurations, whereas it was restricted in the EP configuration. The mobility decreased with the increase in slope angles at LV configurations. Strand protrusion of the blocks made the elevation of the deposits at LV configuration larger than that at EP, LP and R configurations. A zigzag structure is created in the blocks resulting from the lateral spreading of the deposits causing the blocks to rotate. Varying degrees of deflection of the blocks demonstrated different levels of collision and friction in the interior of the mass flows; the most intensive collision was observed at EP. In the mass deposits, the blocks' orientation was affected by their initial configurations and the motion process of the mass flows. This research would support studies relating characteristics of structural geology of source volume to landslide mobility and deposit morphology.

Effect of structural setting of source volume on rock avalanche mobility and deposit morphology

Effect of structural setting of source volume on rock avalanche mobility and deposit morphology

Geodiversity in Khorat Geopark, Thailand: Approaches to geoconservation and sustainable development

This work aims to investigate the geodiversity of the Khorat Geopark area, Northeastern Thailand, and assess the geological sites that are connected to biological and cultural heritage, as well as community activities that enhance geoconservation and sustainable development. The geological diversity of Khorat Geopark dates back to the late Jurassic period and continues to the present day, resulting from the deposition of terrestrial sedimentary rocks from the Khorat Group. The Khorat rock group has been uplifted and eroded to form the Khorat Plateau with a unique landscape and important geological features of the cuesta landform on the western part of the Khorat Geopark. On the four corners of Nakhon Ratchasima City, there are numerous fossils of outstanding Early Cretaceous dinosaurs and other reptiles and Cenozoic fossils of both flora and fauna, mainly mammalian remains and, in particular, ancient elephants. Geological sites in the Khorat Geopark area were weighted and scored based on their scientific value (SV), potential value for education (EV), potential value for tourism (TV), and degradation risk variables (DV). According to the assessment, the Khorat Geopark's 24 geosites are of moderate to high value, with 7 sites having 301–400 scores and 5 sites having a high level of international value. Most of them are related to fossils and cuestas. Thus, the fossil diversity of the Khorat Geopark is of international scientific significance. Khorat Geopark is managed under the conservation, education, and sustainable development initiatives using a bottom-up method with multiple networks, both local communities and local governments, especially through the Home-Temple-School (HTS) model.

Implementation and Verification of Effectiveness of Bulk Emulsion Explosive with Improved Energetic Parameters in an Underground Mine Environment

Explosives are commonly used in the mining industry to extract minerals from hard rock deposits. Therefore, an efficient explosive should ensure that the appropriate blast outcome is achieved, taking into account the desired rock-breaking parameters and the costs of drilling and blasting works. Depending on the type of deposit and follow-up processes, a proper blast result may be characterized by fragmentation, muckpile shape, overbreaks, etc. Industry has struggled to respond to the demand for bulk emulsion explosives with improved energetic parameters, having so far been unable to do so safely, effectively, and cost-efficiently. Methods of improving blasting parameters mainly rely on introducing a variety of additives to the emulsion explosive formulation during production, which creates additional hazards at that stage. Alternative, safe methods of achieving an improved energetic performance of emulsion explosives are, therefore, highly desirable. This paper is focused on one such proposed method as a continuation of previous research works and the performance of a novel bulk emulsion formulation under real mining conditions during the firing of mine faces is described. The tests included density measurements over time, measurements of impact and friction sensitivity, measurements of the detonation velocity in blastholes, determination of brisance via Hess test, and analysis of rock fragmentation. Results were compared with those obtained with a commercially available bulk emulsion explosive, highlighting that the performance improvement achieved by the proposed emulsion modification method is not limited to artificial test conditions, but translates well into actual application conditions.