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The sedimentary environment and organic matter (OM) accumulation are vital indicators for shale gas exploration. However, research on deep shale gas systems is relatively limited; moreover, the exploration of deep shale gas in the southeastern Sichuan Basin has entered a period of stagnation. In this study, systematic geochemical analysis of Wufeng (WF) and the first member of the Longmaxi (Long-1) deep shale samples from the recently drilled DY7 well in the Dingshan area of the Sichuan Basin is carried out, and the longitudinal variations in major and trace elements are revealed. The differences in the WF, lower section of the Long-1 (Long-11) and upper section ofthe Long-1 (Long-12) shales are studied in terms of redox conditions, paleoproductivity, terrigenous detrital input, sedimentation rate and paleoclimate, and the different main controlling factors of OM accumulation for these three layers are discussed. The WF shale has a higher TOC content (mean: 5.73%), the Long-11 shale has a high TOC content (mean: 2.89%), while the Long-12 shale has a low TOC content (mean: 1.44%). For the WF shale, due to complex geological events and large fluctuations in element contents, its TOC content is poorly correlated with these indices, redox and paleoproductivity proxies have a positive association with the Long-11 shale's TOC content, but negatively correlated with terrigenous input and sedimentation rate indices. The formation of these two sets of organic-rich shales (TOC > 2%) is jointly controlled by good preservation conditions. In contrast, the TOC content of the WF shale is higher than that of the Long-11 shale as the result that terrigenous input and sedimentation rate of the Long-11 shale represent the dilution and destruction of OM, which is different from the former. During the Long-12 depositional period, the water column experienced weak reducing conditions and low productivity, and its high terrigenous debris input further diluted the OM, leading to a low TOC content. [ABSTRACT FROM AUTHOR]

In order to study the distribution pattern of oil and gas near the lower-source, upper-storage type of oil source faults in the hydrocarbon-bearing basins, a set of prediction methods favourable to oil and gas migration and accumulation were established by superimposing the parts of the oil source fault-associated traps, the contiguously distributed sand bodies and the lateral sealing position of faults. The trap associated with a fault can be determined by the fault's convex part on the fault plane's morphology map, the fault throw displacement curve and the intersection of faults on the structure map. The set of sand bodies can be determined by the sand-to-shale ration of the formation. The lateral sealing position of faults can be investigated by the shale content of the fault. This study is based on our case study of the Dazhangtuo Fault in the lower sub-member of the 1st member (Es1L) of the Shahejie formation in the northern Qikou Sag of Bohai Bay Basin. The results illustrate 4 fault nose traps formed by fault line deflection in the Es1L formation of the Dazhangtuo Fault, 2 each in the middle and eastern end. The Dazhangtuo Fault is favorable for oil and gas migration except at the eastern and western ends and the middle part of the fault. The fault-associated traps in the Es1L formation that are highly favorable for hydrocarbon migration and accumulation (overlapping site of associated traps and favorable location for oil and gas migration) are distributed in the eastern and central parts of the Dazhangtuo Fault. In contrast, those moderately favorable for hydrocarbon migration and accumulation (associated trap at a certain distance from the favorable location for oil and gas migration in the Dazhangtuo Fracture) are locally distributed in the east. Both traps are conducive to accumulating hydrocarbons from the underlying source rock in the Es3 formation. Such observations are consistent with the current confirmed hydrocarbon distribution, thus validating the feasibility and accuracy of predicting the distribution of traps related to oil source faults favorable for hydrocarbon migration and accumulation, it can be used to guide the exploration of the lower-source, upper-storage type of hydrocarbon accumulations in the hydrocarbon-bearing basins. [ABSTRACT FROM AUTHOR]

Despite fertilization efforts, phosphorus (P) availability in soils remains a major constraint to global plant productivity. Soil incorporation of biochar could promote soil P availability but its effects remain uncertain. To attain further improvements in soil P availability with biochar, we developed, characterized, and evaluated magnesium-oxide (MgO) and sepiolite (Mg4Si6O15(OH)2·6H2O)-functionalized biochars with optimized P retention/release capacity. Field-based application of these biochars for improving P availability and their mechanisms during three growth stages of maize was investigated. We further leveraged next-generation sequencing to unravel their impacts on the plant growth-stage shifts in soil functional genes regulating P availability. Results showed insignificant variation in P availability between single super phosphate fertilization (F) and its combination with raw biochar (BF). However, the occurrence of Mg-bound minerals on the optimized biochars' surface adjusted its surface charges and properties and improved the retention and slow release of inorganic P. Compared to BF, available P (AP) was 26.5% and 19.1% higher during the 12-leaf stage and blister stage, respectively, under MgO-optimized biochar + F treatment (MgOBF), and 15.5% higher under sepiolite-biochar + F (SBF) during maize physiological maturity. Cumulatively, AP was 15.6% and 13.2% higher in MgOBF and SBF relative to BF. Hence, plant biomass, grain yield, and P uptake were highest in MgOBF and SBF, respectively at harvest. Optimized-biochar amendment stimulated microbial 16SrRNA gene diversity and suppressed the expression of P starvation response and P uptake and transport-related genes while stimulating P solubilization and mineralization genes. Thus, the optimized biochars promoted P availability via the combined processes of slow-release of retained phosphates, while inducing the microbial solubilization and mineralization of inorganic and organic P, respectively. Our study advances strategies for reducing cropland P limitation and reveals the potential of optimized biochars for improving P availability on the field scale. Article Highlights: MgO and sepiolite doping optimized biochar's surface properties for phosphorus (P) retention and slow release The potential formation of Mg-PO4 phases on the optimized biochar surface regulated P retention and release MgO and sepiolite-ptimized biochars increased soil available P by promoting microbial P mineralization and solubilization. [ABSTRACT FROM AUTHOR]

Research has been conducted on the development of an innovative organomineral fertilizer based on local lake resources as a stimulator of germination and growth of crops, as one of the factors in achieving the goal of environmental sustainability. The results obtained are based on the environmental friendliness of the technology, increasing yields, and obtaining environmentally friendly products. This, in turn, will not only save mineral resources but also make it possible to use the resources from the bottom sediments of local lakes, and their rational extraction will contribute to the sustainable development and restoration of lake ecosystems. This article highlights the results of laboratory and field studies on the use of sapropel extract at the stage of pre-sowing seed treatment obtained by extraction of bottom sediments from lakes in Northern Kazakhstan. Solutions of aqueous alcohol extract of sapropel extract with concentrations of 0.4, 0.8, 1.2, 1.6, 2.0 g/L and table beet seeds (Beta vulgaris L.) of Bordo 237 variety were used as objects of research. Statistical analysis of laboratory experience data, based on the determination of germination energy and seed germination, allowed us to identify the optimal concentration of sapropel working solution for pre–sowing seed treatment—1.6 g/L. The index of germination energy and germination of seeds during pretreatment with sapropel extract of this concentration was 40% and 50%, respectively. This contributed to an increase in germination energy by almost 2 times and in seed germination by more than 40%. Pre-sowing treatment of seeds with sapropel extract at a concentration of 1.6 g/L in a field experiment contributed to the improvement of biometric indicators of beet fruits, such as diameter, length, and weight. The results of the data on fetal weight of the experimental variant compared with the control were 27% higher, and they were 26% and 32% higher compared with other experimental variants. In the experimental group, the highest yield index was also established, which is 2.15 times, or 53%, higher than the control, which emphasizes the effectiveness of pre-sowing seed treatment with the resulting sapropel suspension. A patent of the Republic of Kazakhstan was issued for the method we developed for obtaining a sapropel product for pre-sowing treatment of seeds: "A method for obtaining a sapropel product for pre-sowing treatment of vegetable seeds". The research presented in the article confirms its effectiveness. The use of this product in pre-sowing seed treatment reduces the number of agrotechnological operations and costs, which makes this method more efficient and economically beneficial for the agricultural industry. Thus, the principle of food security will be implemented, contributing to the preservation of sustainable development and having a positive impact on the health of the population. [ABSTRACT FROM AUTHOR]

Copyright of Karaelmas Science & Engineering Journal / Karaelmas Fen ve Mühendislik Dergisi is the property of Karaelmas Science & Engineering Journal 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.)

Basin modeling and thermal maturity estimation are crucial for understanding sedimentary basin evolution and hydrocarbon potential. Assessing thermal maturity in the oil and gas industry is vital during exploration. With artificial intelligence advancements, more accurate evaluation of hydrocarbon source rocks and efficient thermal maturity estimation are possible. This study employed 1D basin modeling using PetroMod and a novel hybrid group method of data handling (GMDH) neural network optimized by a differential evolution (DE) algorithm to estimate thermal maturity (Tmax) and assess kerogen type in Triassic–Jurassic source rocks of the Mandawa Basin, Tanzania. The GMDH–DE addresses the limitations of conventional methods by offering a data-driven approach that reduces computational time, overcomes overfitting, and improves accuracy. The 1D thermal maturity basin modeling suggests that the Mbuo source rocks reached the gas–oil window in late Triassic times and began expulsion in the early Jurassic while located in an immature-to-mature zone. The GMDH–DE model effectively estimated Tmax with high coefficient of determination (R2 = 0.9946), low root mean square error (RMSE = 0.004), and mean absolute error (MAE = 0.006) during training. When tested on unseen data, the GMDH–DE model yielded an R2 of 0.9703, RMSE of 0.017, and MAE of 0.025. Moreover, GMDH–DE reduced the computational time by 94% during training and 87% during testing. The results demonstrated the model's exceptional reliability compared to the benchmark methods such as artificial neural network–particle swarm optimization and principal component analysis coupled with artificial neural network. The GMDH–DE Tmax model offers a unique and independent approach for rapid real-time determination of Tmax values in organic matter, promoting efficient resource assessment in oil and gas exploration. [ABSTRACT FROM AUTHOR]

The evolution of gas hydrates influenced by the seawater environment is unknown. We present a model of structural transformation from sI hydrate to sII hydrate due to the influence of seawater environment and vent fluid in nature through in situ experiments of gas hydrate formation in the Haima cold seep area. The in situ experimental results indicate that gas hydrates preferentially form as sI hydrates even in cold seep environments where C2+ hydrocarbons are present. During subsequent evolution, the sI hydrates could restructured at the effect of seawater environment and vent fluid, causing transformation to sII hydrates under the influence of hydrate stability. The supply of gas and direct contact with seawater environment are critical factors for structural transformation. Such structural transformation is the result of gas hydrates seeking thermodynamic stability and may be common in active cold seep areas. Plain Language Summary: At high pressures and low temperatures, methane molecules are able to be captured by water in a solid hydrate state, known as natural gas hydrate. The significance of the abundant reserves of natural gas hydrates in the oceans, both in terms of global climate issues and energy resources, has been widely recognised. Since most natural gas reservoirs are dominated by methane (>90%), it is generally accepted that gas hydrates in the oceans tend to be structure I. However, through a field experiment in an active cold seep area, we found that newly generated gas hydrates under the influence of the same cold seep area were of structure I, whereas naturally exposed gas hydrates that had existed for a long period of time on the seafloor were instead of structure II. Based on this, we propose a model of structural transformation (structure I to structure II) of gas hydrates under the influence of seawater environment and vent fluid. This structural transformation may be a natural phenomenon that is common in active cold seep areas. Key Points: In situ experiments have demonstrated that gas hydrates can undergo structural transformation under the influence of seawater environmentNatural structural transformations of gas hydrates are probably common, especially in active cold seep where C2+ hydrocarbons present [ABSTRACT FROM AUTHOR]

Shallow-water deltas serve as a critical area for the exploration and development of terrestrial lacustrine oil and gas reservoirs. Current research on oil and gas exploration and development in China's terrestrial lacustrine basins primarily focuses on their delta front facies zones. Despite extensive discussions on the sedimentary characteristics of shallow-water deltas by predecessors, there is a lack of comprehensive analysis on the combined effects of dynamic factors such as climate change, lake level fluctuations, and sediment supply. This paper, through a detailed examination of 12 core samples and integrating data from 493 exploratory, appraisal, and development wells in the study area, establishes a stratigraphic correlation framework using well–seismic integration techniques. It identifies two main sedimentary facies types in the southern Da'anbei area of the Songliao Basin: shallow-water deltas and lake facies, which can be further subdivided into four sub-facies and nine microfacies. Two depositional models for the shallow-water deltas of the Southern Songliao Nenjiang Formation are established: a deeper water background with channel-river mouth bar sequences forming the delta front framework and a shallower water background with channel-sheet sand sequences forming the delta front framework. This paper also discusses the controlling effects of paleoclimate, sediment supply, and lake level changes on sedimentary evolution, providing a scientific basis for the exploration of lithologic oil and gas reservoirs in the Nenjiang Formation of the study area and the deployment of horizontal wells. [ABSTRACT FROM AUTHOR]

In the central Tarim Basin, numerous hydrocarbon deposits were found along ultra-deep strike-slip faults, and its evolving progress and formation mechanism are research hotspots. The Paleozoic small-angle X-type strike-slip fault in the Tabei Uplift is the research subject in this article. Based on high-precision three-dimensional seismic data, three structural deformation layers were revealed: the rift system, weak strike-slip deformation and salt tectonics in the deep structural layer (Sinian-Middle Cambrian), the strong strike-slip deformation and karst-dissolution structure in the middle structural layer (Upper Cambrian-Middle Ordovician), and echelon normal faults in the shallow structural layer (Upper Ordovician-Carboniferous). The formation and evolution of strike-slip faults is jointly controlled by the distribution pattern of basement rift and the activities of surrounding orogenic belts, which can be divided into three stages. In the Middle to Late Cambrian, the initial subduction of the Paleo-Asian and Proto-Tethyan oceans precipitated the emergence of two sets of small-angle X-type strike-slip faults, striking NW and NE above the grooves of Precambrian rifts, influenced by local weak compressive stress. Affected by the closure of peripheral paleo-ocean, strike-slip faults deformed considerably in the Middle-Late Ordovician and were reactivated in the Silurian-Carboniferous, forming en-echelon normal faults in the shallow layer. The layered deformation structure of the strike-slip faults significantly affects the accumulation of hydrocarbons. The differential hydrocarbon enrichment of faults in the Tabei Uplift is collectively influenced by the distribution of source rocks and the migration of oil and gas. The topographical features of the Tabei Uplift, along with the distribution of strike-slip faults across tectonic units, have rendered the NE direction the preferential pathway for hydrocarbon migration. Additionally, impacted by the development of en echelon faults, the NE-trending faults offer superior conditions for hydrocarbon preservation and charging condition, compared to the NW-trending faults. [ABSTRACT FROM AUTHOR]

The controlling factors of organic-rich shale accumulation is essential for the exploration and development of shale oil and gas resources. The sedimentary environment plays a vital role in the formation of organic-rich sediments in lacustrine facies. This article unravels the mineralogy, geochemistry, and paleoenvironmental evolution during the deposition of the Paleogene Shahejie Formation (Es3 L). It discusses the effects of paleoclimate, paleosalinity, paleoredox conditions, paleowater depth, and paleoproductivity on organic matter (OM) enrichment. Finally, the OM enrichment model was established. The results show that the mineralogical compositions are mainly composed of calcite (avg. 40.13%), quartz (avg. 21.64%) and clay minerals (avg. 24.07%), accompanied by dolomite (avg. 7.07%), feldspar (avg. 6.36%) and pyrite (avg. 2.95%). The Es3 L shale has a high abundance of OM, with total organic carbon (TOC) ranging from 1.07% to 5.12%. The organic matter type is mainly composed of type I-II1 kerogen, which is generally considered a good-quality source rock. The source of OM is a mixture of lower bacteria, algae, and plants. During the early sedimentary period, the paleoclimate was dry and cold, with high salinity, intense reducibility, and relatively low productivity. During the late sedimentary period, the climate became warmer and more humid. As a result, the salinity decreased to a level that was suitable for biological reproduction, and productivity increased gradually due to the input of terrigenous plants. Paleosalinity and paleoclimate determined the environment of the sedimentary period, in addition, paleoproductivity and paleoredox condition indicated the formation and preservation conditions of OM. The warm and humid climate, brackish water, suitable reduction conditions and high productivity are the favorable conditions for the generation and preservation of organic matter. The research results may have implications for the genetic mechanisms of organic matter accumulation. They will provide theoretical and technical insights into the exploration and development of shale oil. [ABSTRACT FROM AUTHOR]

Sources and fluxes of methane to the atmosphere from permafrost are significant but poorly constrained in global climate models. We present data collected from the variable permafrost setting of the outer Mackenzie River Delta, including observations of aquatic methane seepage, core determinations of in situ methane occurrence and seep gas isotope geochemistry. The sources and locations of in situ geologic methane occurrence and aquatic and atmospheric gas release appear to be controlled by the regional geology and permafrost conditions. Where permafrost is >250 m thick, thermogenic gas deposits at depth are isolated by laterally continuous, low permeability ice‐bearing sediments with few through‐going thawed taliks. Thus, the observed in situ methane and aquatic gas seepage appears to be dominated by microbial methane. In contrast, where permafrost is <80 m thick, taliks are more likely to be through‐going, providing permeable conduits from depth and migration pathways for both thermogenic and biogenic gas. Continuous annual fluid sampling of two lakes and a river channel documents aquatic methane flux from microbial sources, more deeply buried thermogenic sources, and mixtures of both. Using estimates of in situ methane concentration from deep core samples and observations of in situ free gas occurrences, we conclude that the reservoir of in situ geologic methane within ice bonded permafrost is substantial and that this methane is presently migrating with ongoing atmospheric release. It is our assessment that the permafrost setting, and processes described are sensitive to future climate change as the permafrost warms. Plain Language Summary: Methane is released from permafrost, yet the amount and sources of the methane are poorly understood. This paper presents data on methane released from water environments and stored in soil from the permafrost areas of the outer Mackenzie River Delta, NWT. It also uses isotope geochemistry to determine the source (type) of the methane ‐ either biogenic (produced by living organisms) or thermogenic (produced by breaking down of organic matter by heat). The sources and locations of the methane gas release appear to be controlled by the regional geology and permafrost conditions. We conclude that the methane stored within and beneath the ice bonded permafrost is substantial and that this methane is presently migrating to aquatic systems with ongoing atmospheric release. It is our assessment that this permafrost setting and the potential for increased methane release are sensitive to future climate change as the permafrost warms. Key Points: A unique annual record of dissolved methane geochemistry documents active microbial and geologic methane sources in a delta lake and channelSeep gas chemistry, geophysical, and core data allow appraisal of permafrost controls on subsurface methane dynamics in the Mackenzie DeltaThe large inventory of stored methane and the dynamic permafrost processes described are potentially responsive to future climate change [ABSTRACT FROM AUTHOR]

As a hydrocarbon-rich depression within the Bohai Bay Basin, the Huanghekou Depression is a focal region for exploring hydrocarbons in the eastern China Sea. Previous studies have insufficiently examined the correlation between the enrichment of organic matter and the environments in which it is deposited. Herein, the hydrocarbon potential, palaeoclimate, sedimentary environment, organic matter sources, and organic matter enrichment of the source rocks of the Shahejie Formation in the Huanghekou Depression were investigated using organic and inorganic geochemical indicators. The organic matter type of the source rock in Huanghekou Depression's Shahejie Formation was predominantly Type II, with a minor presence of Type III. Furthermore, the source rock had a poor-to-good comprehensive evaluation grade in E3s1–2, whereas E2s3 and E2s4 had medium-to-good comprehensive evaluations in their source rocks. In terms of maturity, E3s1 was in an intermediate position between the immature and mature stages and E3s2 and E2s3 were between the low-maturity and mature stages, whereas E2s4 transitioned into full maturity. Biomarkers and sensitive element indicators indicated that the organic matter in E3s1–2 was primarily derived from lower aquatic organisms and algae. This palaeoclimate was characterised by aridity, a water body containing saline and semi-saline water, and a strongly reducing environment resulting from water body stratification, leading to oxygen deficiency. The organic matter in E2s3 was primarily derived from aquatic organisms and algal inputs; these deposits were formed in a reduced environment characterised by relatively low salinity, ranging between semi-saline and freshwater conditions. The organic matter enrichment model of the Shahejie Formation was established based on sedimentary environment, palaeoclimatic, and organic matter source analyses, utilising E3s1–2 as preservation models and E2s3 as the productivity model. This study provides a basis for in-depth exploration and advancement of oil and gas reserves. [ABSTRACT FROM AUTHOR]

This study predicts favorable oil and gas source-rock formation conditions in the Aryskum Depression of the South Turgay Basin, Kazakhstan. This study assesses the thermal maturity and characteristics of organic matter by determining its environmental conditions using data from geochemical analysis of core (pyrolysis) and oil (biomarkers and carbon isotopic compositions) samples. According to the geochemical parameters obtained by pyrolysis, the oil generation potential of the original rocks of most studied samples varies from poor to rich. The facies–genetic organic matter is predominantly humic and less frequently humus–sapropel, indicating organic matter accumulation in the studied samples were under moderately reducing conditions (kerogen III and II types) and coastal–marine environments (kerogen type I). The carbon isotopic compositions of oils derived from the Jurassic deposits of the Aryskum Depression also indicate the sapropelic and mixed humic–sapropelic type of organic matter (kerogen II and I). Biomarker analysis of oils indicates original organic matter formation in an anoxic environment. [ABSTRACT FROM AUTHOR]

Among the species of the genus Crotalaria L., Crotalaria juncea is the only cover crop cultivated for its fiber. The quality of the latter depends on the nutritional conditions, accumulation of biophilic elements in the biomass, and synthesis of proteinogenic amino acids. Thus, the purpose of this study was a qualitative and quantitative assessment of the green harvest at the active flowering stage, before the bean formation phase, when the entire biochemical cycle of the plant is reconfigured, and the biochemical indicators are maximum. The plants were grown for 140 days (from April 22 to September 9, 2023) in protected soil conditions. The experimental design consisted of two units of 50 plants each: in the first (control) unit, plants were grown in a soil mixture without any additives; in the second one, they were treated three times during the growing season with an organic suspension of humic acids (1000 ppm) obtained from sapropel (Pskov oblast, UDHSS) by applying it when watering at the root. The soil substrate in both cases was typical chernozem (Kamennaya Steppe Nature Reserve, Voronezh oblast, 51°01′41.6″ N, 40°43′39.3″ E) with a 20% addition of volcanic zeolite. Over the course of every 14 days, morphometric trends of the crop growth (height and dry biomass) were systematically recorded with the removal of five cultivars from each unit of options. After 140 days, the remaining five replicates per option were subjected to biochemical analysis by inductively coupled plasma mass spectrometry (ICP-MS) and high-performance liquid chromatography (HPLC) using the 7500 and LC 1200 devices (Agilent Technologies, United States) according to the manufacturer's method. Treatment with UDHSS increased productivity and shoot height by 51.1% and 11.3%, respectively. The microelement concentration order in the dry biomass was as follows: Na > K > Ca > S > P > Mg in the control option and Na > K > Ca > Mg > P > S in the UDHSS option, while the microelement export was observed as Fe > Mn > Zn > Ba > B > Cu > Mo and Fe > Mn > B > Zn > Ba > Cu > Mo. In total, the increase was more evident in the microelement accumulation due to a twofold increase in the concentration of iron ions. As for amino acids, L-lysine, L-glycine, L-glutamine, and L-tyrosine became higher. The first three are structural components of biological tissues indirectly indicative of an increase in the fiber strength of the plant culture. [ABSTRACT FROM AUTHOR]

Humic substances (HS) belong to a fairly common class of organic compounds in nature, which are a component of soils, peat, lignite and sapropels. Some properties of humates (salts of humic acids) make it possible to use them in various fields – crop production, animal production, well drilling and soil structuring. The biological and chemical activity of humic substances is well known. It is caused by the presence of such functional groups as carboxyl, hydroxyl, carbonyl, nitrogen- and sulfur-containing in the composition of GR macromolecules. This fact also serves as a basis for a more extensive study of other properties of GR, namely antioxidant activity. Purpose. Deepening and expanding the understanding of the biological and antioxidant activity of lignite humic (HA) and hymatomelanic (HmA) acids, determining its nature and evaluating the prospects of its use in little-studied processes of oxidation of organic and consumer substances. Methodology. The paper used a photocolorimetric method for determining the antiradical activity (ARA) of two components of humic substances of domestic lignite - humic and hymatomelanic acids. The antioxidant activity (AOA) of humic and hymatomelanic acids from lignite was determined using the gas volumetric method, evaluating the rate of reaction inhibition using the example of the initiated liquid-phase oxidation of cumene with oxygen. Findings. It was established that humic acids exhibit more pronounced antioxidant properties in the processes of radical-chain oxidation of hydrocarbons compared to hymatomelanic acids. The total AOA of HA is 1.68 relative units, which is almost three times higher than this figure for HmA (0.50). On the other hand, it has been experimentally proven that hymatomelanic acids have more pronounced antiradical properties than humic acids. ARA HmA is 0.90 relative units, which is approximately three times more than the similar value for HA (0.57). Originality. Despite the fact that a number of methods for determining the antiradical and antioxidant activity of low-molecular antioxidants and their mixtures have been developed, a method for determining these indicators for high-molecular native compounds has not yet been created. For the first time, a method for determining the antiradical effect of humic substances using the stable 2.2-diphenyl-1-picrylhydrazyl radical (DPPH) was proposed and experimentally tested. A method for determining the antioxidant activity of humic and hymatomelanic acids in hydrocarbon oxidation processes (on the example of cumulus) has been developed. The convenience and satisfactory reproducibility of the developed methods are shown. Practical value. The green-chemistry related development and application of drugs based on native and modified humic substances as polymers with adjustable redox properties (redox polymers) is a relevant direction of sustainable development of society. These substances are the basis for obtaining new medicines, plant protection products, new sorbents, preparations for the reclamation of territories contaminated with radionuclides, heavy metals, organic ecotoxicants, oil products, etc. [ABSTRACT FROM AUTHOR]

Hydrocarbon gases formed from biotic and abiotic processes are released through the seafloor at different locations around the world. They have been widely observed directly in video and photo data, and indirectly on echosounder data. Even though biotic gas generation is a very common process, abiotic gas generation is limited to regions where serpentinization of ultramafic rocks occur. Indications of abiotic gas occurrences are therefore sparse and much speculated upon. Here, we investigated the Spitsbergen Transform Fault, the Molloy Ridge, the Molloy Deep, and the Molloy Transform Fault/Fracture Zone, (a transform fault-bounded pull-a-part region offshore western Svalbard) where both processes may be active. Multiple acoustic gas flares, ~1,770 and ~3355 m high above the seafloor (tallest ever recorded), were observed indicating active migration and seepage of hydrocarbons. The proximity to the mid oceanic ridge and the documented high heat flow suggests the influence of high temperatures on organic-rich sedimentary deposits. Deep seismic data and other geological information available indicate that the main source of gas could be from thermal cracking of either pre- or syn-rift source rock organic material, potentially mixed with methane from serpentinization of mantle rocks (peridotites). Correlation with seismic stratigraphy from Ocean Drilling Program (ODP) Sites 910 and 912 on the adjacent Yermak Plateau suggests that the sedimentary source rocks may be present at the northern flank of the Molloy Ridge and within the deep graben along the Spitsbergen Transform Fault. The ~3 km thick sedimentary succession in high heat flow zones within the transform fault and the active bounding faults allow generation and migration of hydrocarbons to the seafloor and sustains present day seepage. [ABSTRACT FROM AUTHOR]

The study investigated the sorption behaviour of 99Tc and 125I on bottom sediments from the Japan Sea, Khanka Lake and commercially available sapropel. It was determined that organic matter can have an impact on the iodine sorption process. After a 20-day period, sapropel reached an equilibrium state with a sorption value of up to 100%. In real systems of bottom sediment–water in the Far East region, iodine sorption was found to be superior on marine bottom sediments with a sorption value reaching 85% within 20 days, as opposed to freshwater sediments which only reached up to 35% within the same period. Tc(VII) in the form of pertechnetate anion exhibits no sorption under either aerobic or anaerobic conditions in the pH range of 4–11. Under aerobic conditions at pH 11 Tc(IV) is sorbed up to 15% only on sapropel; under anaerobic conditions at pH 7 the sorption reaches 25% for lake sediments, 10% for marine sediments and when the pH is 11, the sorption value of Tc by sapropel is as high as 100%. [ABSTRACT FROM AUTHOR]

This study presents the results of a 2D numerical basin and petroleum systems model of the Olga Basin in the NW Barents Sea offshore northern Norway, a frontier exploration area in which there are abundant seafloor oil and gas seepages. The effects of Pleistocene ice sheet advances on rock properties and subsurface fluid migration in this area, and on seafloor hydrocarbon seepage, are not well understood. The 2D numerical model takes account of recurrent ice advances and retreats, together with related erosional and temperature effects, and investigates the influence of these parameters on fluid migration. Model results show that Pleistocene glaciations reduced the temperature in the sedimentary succession in the Olga Basin by up to 20 °C, for example in the uppermost Cretaceous and Jurassic sediments which underlie the seafloor down to a depth of 0.5 to 1 km. The decrease in temperature was in general predominantly related to the intensity of glacial erosion, which was set in this study to a depth of 600 m based on previous studies. Hydrocarbon fluids expelled from potential thermogenic source rocks of Carboniferous to Triassic ages on the SW margin of the Olga Basin migrated to the seafloor through permeable carrier beds. However, fluid migration to the surface in the NE of the study area took place along fault conduits. In a closed fault model scenario, only 0.3 Mt of hydrocarbons are modelled to have migrated along the 0.5 km wide model section; in a second scenario with partially open faults, about 22 Mt of hydrocarbons, representing about 11% of the total hydrocarbons generated by potential thermogenic source rocks in the study area, were lost to the surface during the Pleistocene. The potential for microbial methane generation in the Olga Basin was limited both during the Pleistocene and at the present day due to the significant reduction in temperature during glacial episodes, and due to the intense glacial‐related erosion of the Mesozoic to Cenozoic stratigraphy. During glacial stages, the gas hydrate stability zone beneath the ice sheet is modelled to have extended to a depth of up to 900 m for a pure methane composition, and to a depth of up to 1100 m for a possible thermogenic‐sourced mixed gas composition of 90% methane, 7% propane and 3% ethane. Gas hydrates with this mixed composition are modelled to have been stable in the Olga Basin during the last three glacial advances and into the present. These modelling results provide an insight into the key factors controlling the migration and surface leakage of hydrocarbon fluids in the Olga Basin region, and into the effects of glaciations on rock properties in a glaciated basin. [ABSTRACT FROM AUTHOR]

Copyright of Archives of Environmental Protection is the property of Polish Academy of Sciences 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.)

In the Mediterranean Sea, organic carbon-rich sapropels have been deposited periodically over the last fifteen million years. Some sapropels are characterized by high contents of the mat-forming, planktonic diatom Pseudosolenia calcar-avis and the planktonic diatom Thalassionema nitzschioides as a result of their mass sinking in autumn (the so-called "fall dump"). The present study shows that fall dump events also occurred in the brackish Baltic Sea around 6300–5800 calibrated years before present (cal yr BP; present = AD 1950). In sediments from the northern Baltic Sea these events are evidenced by high contents of a lipid specific for P. calcar-avis (a C25:2 highly branched isoprenoid alkene) and corroborated by fossil remains of both P. calcar-avis and T. nitzschioides. A biomarker index based on long-chain alkyl diol lipids indicates that mat-forming Proboscia diatoms were also present. High contents of calanoid resting eggs further suggest that the copepod population was stressed being unable to feed on such large diatoms. The fall dump events occurred during a complete stratification of the water column and euxinic conditions, as reflected by the redox-sensitive trace metal uranium, allowing upward diffusion of nutrients and the growth of rhizosolenid mat-forming diatoms in a deep chlorophyll maximum. Synchronous remains of P. calcar-avis in the central Baltic Sea further suggest that these events occurred on a basin-wide scale. [ABSTRACT FROM AUTHOR]

Background and Objective: Sapropel, a biologically active sedimentary deposit, is high in organic matter and minerals and has been shown to offer health benefits. Its constituents, humic acid (HA) and fulvic acid (FA), have been found to have some therapeutic applications. The aim of this study was to determine the potential therapeutically significant properties of freshwater sapropel extracts: their polyacid content, antioxidative (AO) status, and biological activity in cell culture. Materials and Methods: Freshwater lakes from the southeast region of Latvia were investigated layer by layer. The total organic carbon (TOC) was determined through combustion using the catalytic oxidation method, HA and FA were measured via acid perspiration, and the total polyphenol content (TPC) and total antioxidant status (TAS) was analysed spectrophotometrically. Sapropel extracts' regenerative abilities were tested in vitro using a Cell-IQ real-time monitoring system on mouse BALB/c 3T3 fibroblasts and human keratinocyte HaCaT cell lines. Cytotoxicity was measured through neutral red uptake assessment as a concentration-dependent reduction in the uptake of neutral red dye relative to a vehicle control or untreated cells. Results: The highest AO activity was observed in sapropel extracts with elevated concentrations of HA and TPC from Audzelu Lake (1.08 ± 0.03 mmol/L), and the lowest activity was found in extracts from Ivusku Lake (0.31 ± 0.01 mmol/L). Correspondingly, the concentrations of HA in Audzelu and Ivusku Lakes were recorded as 45.2 and 27.4 mg/g, respectively. High concentrations of HA promoted in vitro cell growth upon short-term exposure (up to 6 h). Conclusions: The results show that high TPC correlates with AO status and sapropel extracts with higher concentrations of HA exhibit greater AO activity and promote in vitro cell growth, suggesting a perspective use for short-term topical therapeutic skin applications. However, higher concentrations over longer durations showed cytotoxic effects, indicating the need for further investigation. [ABSTRACT FROM AUTHOR]

Clay materials were prepared with clay and sapropel (SP) or clay and modified (frozen) sapropel (FSP) as the main raw materials. Clay-based materials were formed by mixing clay with a different dosage of SP or FSP (5–30 wt.%). The effect of SP or FSP on the properties and biological resistance of clay-based materials was studied. The results show that the bulk density of clay-based materials decreased, and the compressive strength and initial rate of water absorption increased with the increase in the SP or FSP amount in the clay mixture. Research has shown that SP or FSP can be added as a natural additive containing microfibers to improve the mechanical properties of clay materials. When clay bricks had less than 15% sapropel, dry or frozen, we tested the resistance impact of the fungi Rhodotorula mucilaginosa, Stachybotrys chartarum, Cladosporium cladosporioides, and Aureobasidium pullulans under normal conditions. [ABSTRACT FROM AUTHOR]

Climate-induced changes contribute to the thawing of ice-rich permafrost in the Arctic, which leads to the release of large amounts of organic carbon into the atmosphere in the form of greenhouse gases, mainly carbon dioxide and methane. Ground ice constitutes a considerable volume of the cryogenically sequestered labile dissolved organic carbon (DOC) subjected to fast mineralization upon thawing. In this work, we collected a unique geochemical database of the ground and glacier ice comprising the samples from various geographic locations in the Russian Arctic characterized by a variety of key parameters, including ion composition, carbon-bearing gases (methane and carbon dioxide), bulk biogeochemical indicators, and fluorescent dissolved organic matter (DOM) fractions. Our results show that interaction with solid material—such as sediments, detritus, and vegetation—is likely the overriding process in enrichment of the ground ice in all the dissolved compounds. Terrigenous humic-like dissolved organic matter was predominant in all the analyzed ice samples except for glacier ice from Bolshevik Island (the Severnaya Zemlya archipelago) and pure (with low sediment content) tabular ground ice from western Yamal. The labile protein-like DOM showed no correlation to humic components and was probably linked to microbial abundance in the ground ice. The sum of the fluorophores deconvoluted by PARAFAC strongly correlates to DOC, which proves the potential of using this approach for differentiation of bulk DOC into fractions with various origins and biogeochemical behaviors. The pure tabular ground ice samples exhibit the highest rate of fresh easily degradable DOM in the bulk DOC, which may be responsible for the amplification of permafrost organic matter decomposition upon thawing. [ABSTRACT FROM AUTHOR]

The organic‐rich shale of the seventh Oil Member (Chang 7 Member for short) of the Middle‐Late Triassic Yanchang Formation is extensively distributed in the southern margin of the Ordos Basin. Understanding the palaeoenvironmental conditions during the sedimentary period of the Chang 7 Member is crucial to exploring the main factors that control the enrichment of organic matter in high‐quality source rocks. In this study, lithofacies analysis was conducted, and samples were collected from the N36 well located in the southern part of the Ordos Basin. Subsequently, element geochemical analysis was performed to reconstruct the palaeoenvironment, and total organic carbon (TOC) tests were conducted to analyse the characteristics of organic matter enrichment. The findings indicate that the sedimentary period of the Chang 7 Member was characterized by a relatively warm and humid palaeo‐climate and a brackish water environment with oxygen‐poor or sub‐oxygen‐rich conditions, and a gradual decrease in palaeo‐water depth. The parent rock types were mainly felsic igneous rock and intermediate igneous rock, which provide limited nutritional elements for primary producers. The enrichment of organic matter in the Chang 7 Member is influenced by several factors, mainly including palaeo‐salinity, palaeo‐water depth, palaeo‐redox conditions, terrestrial inputs, and palaeo‐climate. The warm and humid palaeo‐climate, higher palaeo‐productivity, relatively higher palaeo‐salinity, lower terrigenous input, deeper palaeo‐water depth, and better preservation conditions are conducive to the development of high‐quality source rock in the Chang 7 Member. [ABSTRACT FROM AUTHOR]

Large amounts of natural gas hydrates have been discovered in the Qiongdongnan Basin (QDNB), South China Sea. The chemical and stable carbon isotopic composition shows that the hydrate-bound gas was a mixture of thermogenic and microbial gases. It is estimated that microbial gas accounts for 40.96% to 60.58%, showing a trend of decrease with the increase in burial depth. A significant amount of gas hydrates is thought to be stored in the mass transport deposits (MTDs), exhibiting vertical superposition characteristics. The stable carbon isotopic values of methane (δ13C1) in the MTD1, located near the seabed, are less than −55‰, while those of the methane below the bottom boundary of MTD3 are all higher than −55‰. The pure structure I (sI) and structure II (sII) gas hydrates were discovered at the depths of 8 mbsf and 145.65 mbsf, respectively, with mixed sI and sII gas hydrates occurring in the depth range 58–144 mbsf. In addition, a series of indigenous organic matters and allochthonous hydrocarbons were extracted from the hydrate-bearing sediments, which were characterized by the origin of immature terrigenous organic matter and low-moderate mature marine algal/bacterial materials, respectively. More allochthonous (migrated) hydrocarbons were also discovered in the sediments below the bottom boundary of MTD3. The gas hydrated is "wet gas" characterized by a low C1/(C2 + C3) ratio, from 2.55 to 43.33, which was mainly derived from a deeply buried source kitchen at a mature stage. There is change in the heterogeneity between the compositions of gas and biomarkers at the site GMGS5-W08 along the depth and there is generally a higher proportion of thermogenic hydrocarbons at the bottom boundary of each MTDs, which indicates a varying contribution of deeply buried thermogenic hydrocarbons. Our results indicate that the MTDs played a blocking role in regulating the vertical transportation of hydrate-related gases and affect the distribution of gas hydrate accumulation in the QDNB. [ABSTRACT FROM AUTHOR]

Under the recent water-limiting crisis on farmlands in the Czech Republic, more sustainable approaches to improve water infiltration and suction within the soil layer useful for plant growth is crucial. This study sought to explore changes induced by applied tillage system, and time after tillage (considering two field conditions; at crop maturity when the soil had consolidated long after tillage, and after tillage and seeding operations). The tillage systems investigated were reduced tillage (RT), occasional tillage (OT), no tillage (NT) and conventional tillage (CT). Soil properties at 0-30 cm depth analysed were dry bulk density, soil organic matter content, saturated volumetric water content and saturated hydraulic conductivity. After the tillage and seeding operations, soil organic matter increased on all conservation tillage plots (RT, OT and NT) but decreased under CT. Insignificant changes in dry bulk density were observed on the conservation tillage plots, whereas CT reduced dry bulk density by 15.3%. Saturated hydraulic conductivity fluctuated significantly under OT and CT, while remaining stable under RT and NT. Generally, significant variability in organic matter influenced changes in saturated volumetric water content and saturated hydraulic conductivity. Changes in dry bulk density on all the tilled plots (RT, OT, and CT) did not show any significant relationship with saturated volumetric water content. Likewise, no significant relationship between changes in bulk density and saturated hydraulic conductivity on all plots were observed. While organic matter improvements under OT positively correlated with saturated volumetric water content, its seasonal dynamics under saturated hydraulic conductivity can be further studied. CT causes high instabilities in both saturated volumetric water content and saturated hydraulic conductivity leading to impaired characteristics during the soil's consolidated state. [ABSTRACT FROM AUTHOR]

This paper presents evidence that fossil Crassostrea oysters experienced much greater longevity than their modern-day descendants. For extant animals, multiple studies have revealed a positive correlation between longevity and adult body size: the larger the organism's size as an adult, the longer its lifespan. Studies have also demonstrated that organisms that take longer to reach skeletal and/or sexual maturity also tend to have longer lifespans. Fossil Crassostrea oysters are generally larger than their modern-day counterparts, and ontogenetic growth curves suggest longer lifespans and generally longer growth intervals. This evidence should be of great interest to Biblical creationists in light of the Bible's claim that humans in the pre-Flood and immediate post-Flood worlds experienced much greater longevities than modern-day humans. Animals may also have once experienced greater past longevity, since whatever genetic or environmental factors were enabling extreme human longevity were likely also operating across the animal kingdom. [ABSTRACT FROM AUTHOR]

Although the eastern African continental marginal basins have discovered giant gas fields, it is not clear whether the Early Jurassic gypsum associated with the main source rocks controls the gas play. In this paper, we use well logging, seismic reflection, and organic geochemistry data to synthesize the distribution and origin of the gypsum deposits and their control over the gas play. The results show that from 201 Ma to 183 Ma, a thick suite of mudstone with thin-layered gypsum began to form in the southern gulf-like sea due to water stratification. With the sea level falling since 183 Ma, a thick suite of gypsum was deposited in some grabens, where the sedimentary environment changed to lagoons. The gypsum increases the maturity threshold depth of Lower Jurassic source rocks and delays the peak time of gas generation, resulting in the ongoing filling of East African natural gas reservoirs and the formation of giant reserves. In addition, the gypsum not only controls the distribution of conventional gas but also makes the Lower Jurassic shale, where the faults are not developed, an important place for shale gas exploration in the future due to the good sealing properties of the gypsum. [ABSTRACT FROM AUTHOR]

The relationship between normal fault displacement (D) and length (L) varies due to numerous factors, including fault size, maturity, basin tectonic history, and host rock lithology. Understanding how fault D and L relate is useful, given related scaling laws are often used to help refine interpretations of often incomplete, subsurface datasets, which has implications for hydrocarbon and low-carbon energy applications. Here we provide a review of D/L scaling laws for normal faults, discuss factors that could influence these relationships, including both geological factors and errors in measurement, and provide a critique of previously published D/L databases. We then present our newly assembled database of 4059 normal faults from 66 sources that include explicit information on: 1) fault length and displacement, 2) host rock lithology, 3) host basin tectonic history, and 4) maturity, as well as fault D and L through time when these data are available. We find an overall scaling law of D = 0.3L0.92, which is similar to previously published scaling equations and that varies in response to the aforementioned geological factors. Our data show that small faults (<1m length) tend to be over-displaced compared to larger faults, active faults tend to be under-displaced compared to inactive faults, and faults with stiffer host rock lithologies, like igneous and carbonate rocks, tend to be under-displaced with respect to faults within softer, more compliant host rocks, like clastic sedimentary rocks. Our dynamic D/L through time data show that faults follow the hybrid fault growth model, i.e., they initially lengthen, during which time they will appear under-displaced, before accumulating displacement. To the best of our knowledge, this is the first comprehensive, integrated, critical study of D/L scaling laws for normal faults and the factors influencing their growth. These revised relationships can now be utilized for predicting fault length or displacement when only one variable is available and provide the basis for general understanding D/L scaling laws in the context of normal fault growth. This underpinning database is open-access and is available for analysis and manipulation by the broader structural geology community. [ABSTRACT FROM AUTHOR]

Sinkholes develop on carbonate landscapes when caves collapse and can subsequently become lake-like environments if they are flooded by local groundwater. Sediment cores retrieved from sinkholes have yielded high-resolution reconstructions of past environmental change, hydroclimate, and hurricane activity. However, our understanding of the internal sedimentary processes of these systems remains incomplete. Here, we use a multiproxy approach including sedimentology (stratigraphy, coarse-grained particle density, bulk organic matter content), micropaleontology (ostracods), and geochemistry (δ13C and δ2H on n-alkanoic acids) to reconstruct evidence for paleolimnology and regional hydroclimate from a continuous stratigraphic record (Emerald Pond sinkhole) in the northern Bahamas that spans the middle to late Holocene. Basal peat at 8.9 m below modern sea level documents the maximum sea-level position at ~ 8200 cal. yr BP. Subsequent upward vertical migration of the local aquifer caused by regional sea-level rise promoted carbonate-marl deposition from ~ 8300 to 1700 cal. yr BP. A shift in coarse particle deposition and ostracods at 5500 cal. yr BP suggests some environmental change, which may be related to one or multiple internal or external drivers. Sapropel deposition from ~ 1700 to 1300 cal. yr BP indicates a fundamental change in limnology to promote increased organic matter preservation, perhaps related to the regional cooling during the Dark Ages Cold Period. We find δ2H28 values are largely invariant from 7700 to 6150 cal. yr BP suggesting a generally stable hydroclimate (mean − 133‰, 1σ = 5‰). The shift to more depleted values (− 156‰, 1σ = 19‰) at ~ 6000–4800 cal. yr BP may be linked to a weakened (eastern displaced) North Atlantic Subtropical High. Nevertheless, additional local hydroclimate records are needed to better disentangle uncertainties from either internal or external influences on the resultant measurements. [ABSTRACT FROM AUTHOR]

Investigating the paleoenvironment and characteristics of source rocks in sedimentary basins is crucial for understanding organic matter accumulation and guiding hydrocarbon exploration. The Lishui Sag, a significant hydrocarbon-bearing depression in the East China Sea, has experienced extensive marine transgression and increasing salinity in the Paleocene, but the changes in accumulation factors of organic matter during this evolution process remain unclear. Through a comprehensive analysis of total organic carbon (TOC), major and trace elements, and biomarker data, this study investigates the characteristics of source rocks from two lithostratigraphic units, namely the Paleocene Yueguifeng and Lingfeng formations, to gain deep insight into the effects of paleoenvironment on organic matter accumulation and hydrocarbon distribution. Our results indicate that the Lishui Sag transitioned from a closed lake to an open-marine environment in the Paleocene, with a shift from warm-humid to arid climate conditions. The biomarker distribution suggests a change in the origin of organic matter, with a higher input of terrestrial organic matter in the Lingfeng Formation. During the early stage, the lacustrine source rocks in the lower Yueguifeng Formation were formed in a relatively humid and anoxic environment within brackish water, resulting in a substantial influx of terrestrial and lacustrine algae organic matter. In contrast, in the late stage, the marine source rocks in the overlying Lingfeng Formation were developed in an arid and oxidizing environment. The lacustrine source rocks in the Yueguifeng Formation were notably more favorable to developing good-quality source rocks. Compared with the other regions, the western and northeastern parts of the study area have greater hydrocarbon generation potential due to the wider distribution of high maturity and organic-rich source rocks, with higher terrestrial and algal organic matter input. Moreover, considering the practical circumstances in the exploration, the northeastern part of the Lishui Sag is recommended as the next exploration target zone. [ABSTRACT FROM AUTHOR]

The effect of salts of humic (HA) and fulvic (FA) acids extracted from ultradispersed humate-sapropel suspension on the growth and development of four basil varieties used for medicinal purposes, as well as on the content of microelements in the above-ground parts of these plants, was studied under conditions of a complete photoculture and a poor nutrient provision. The experiment included midripening Green Large and early-ripening Emily, Lemona, and Marian basil varieties. Plants were grown in a closed grow box for 50 days. Seeds were sown in a soil mix consisting of vermiculite (50%) and peaty-gley soil (50%). The total content of organic matter and Ntotal in this soil mix was 30.4 and 1.4%, respectively; the content of labile forms of P2O5 and exchange K2O was 88.0 and 82.0 mg/kg, respectively; pHKCl was 5.57. The experimental scheme included the following variants: control (1.0 N Knop's solution) and 0.01% solutions of HA or FA salts. The treatment of plants was performed by a single under-root application and a weekly spraying of leaves. According to the performed morphometric and chemical analyses, the best results were shown by var. Lemona plants, whose height and biomass in the treated variant did not differ from the control values (29.75 and 29.00 mg, respectively). Treated plants of this variety also demonstrated insignificant reduction of their photosynthesis efficiency measured by a SPAD optic chlorophyll counter (31.98 relative units on average vs. 35.54 relative units in the control) that indicated the presence of a variety-specific response to the use of such an approach. The least differences between the experimental and control variants observed for the var. Lemona evidenced to the ability of both humic acid fractions to mobilize microelements for the growth of a plant biomass and change of its biochemical composition. [ABSTRACT FROM AUTHOR]

Sapropels are dark, organic‐rich layers found in Mediterranean sediments that formed during periods of bottom water anoxia. While various mechanisms have been proposed to have caused anoxic conditions, a primary factor is considered to be water column stratification induced by freshwater runoff related to intensified North African monsoon precipitation during precession minima. Monsoon intensification also induced Green Sahara Periods that may have impacted North African hominin dispersal. In this study, we present a novel regression‐based deconvolution of a high‐resolution planktonic foraminiferal oxygen isotope record to estimate the combination of freshwater runoff reaching the eastern Mediterranean and associated surface warming of the water column over the past 5 million years. Sapropels are known to occur in clusters associated with periods of high orbital eccentricity. Our analysis reveals a consistent influence of orbital eccentricity in modulating the North African monsoon, and a possible shift in runoff source area induced by the initiation of Northern Hemisphere ice sheets. Our findings provide important insights into the role of the North African monsoon in shaping Mediterranean environmental changes over the past 5 million years. Plain Language Summary: We investigate long‐term changes in monsoon rains over North Africa, which annually result in freshwater flowing into the Mediterranean Sea. Over geological time, Earth's orbital variations have played a significant role in shaping the monsoon and, consequently, the quantity of freshwater entering the Mediterranean. Foraminifera, small marine organisms, record the oxygen isotope composition of their environment in their shells. Notably, the oxygen isotope balance in North African monsoon rains and the Mediterranean Sea differ, but eventually mix upon the freshwater entering into the Mediterranean. Our research combines a statistical analysis of oxygen isotope data preserved in foraminifera shells with a numerical model of the Mediterranean Sea, enabling us to estimate changes in monsoon freshwater input into the Mediterranean over the past 5 million years. This information not only enhances our understanding of monsoon evolution but also provides insights into the potential for hominin migrations in a more lush North African landscape characterized by higher rainfall than today. Key Points: We present quantitative estimates of Plio‐Pleistocene North African monsoon activity based on deconvolution of planktonic foraminiferal δ18OThrough the past 5 million years estimated monsoon activity is consistent with the expected pattern of orbital eccentricity modulationApparent monsoon strengthening at ∼2.6 Ma may be due to shifting runoff sources induced by Northern Hemisphere ice sheet initiation [ABSTRACT FROM AUTHOR]

High-resolution data for planktonic foraminifera and their groups of ecological interest, including Herbivores and Carnivores, combined with benthic foraminifera and a great variety of biogeochemical indices from the SE Aegean sediment core ST5, contribute to a detailed study concerning major and minor climatic episodes during Holocene. The ST5 sediment record, retrieved from the Tilos-Symi marine basin, evidences the impact of the nearby land, the local climate, and the Rhodes Gyre imprint on the eastern Mediterranean water circulation. Pronounced environmental changes are detected during a preconditioning period of ~400 years before the onset of sapropel S1 deposition and during the deposition phases S1a (10.0–8.4 ka BP) and S1b (8.0–6.1 ka BP). Major freshwater influx episodes (10.5 ka BP, 9.2–8.9 ka BP, 7.4 ka BP, 4.5–4.3 ka BP, and few additional during the Late-Holocene) are revealed, prominent oxygen deficiency time intervals (including a distinct brief anoxic period) as well as several drier, cooler and warmer climatic events. Herbivore planktonic foraminifera alternate their dominance with the Carnivores at the preconditioning period before the S1 onset and at the Late-Holocene (2.0–1.5 ka BP) when conditions of good seawater circulation, oxygenation, and productivity alternate with stratified low oxygenation waters and high freshwater influx from the land. [ABSTRACT FROM AUTHOR]

A geological study of the Kipala region, in the "Cuvette Centrale" of the Democratic Republic of Congo, has identified two groups of shales: the dark greasy facies, interbedded with the brownish-gray facies. Their high Total Organic Carbon (TOC) content (11 % TOC on average for the dark greasy shales, compared with 8 % for the second group) classifies them as very good hydrocarbon source rocks, according to the criteria of Epistalie et al. Field and laboratory data suggest that the rocks studied were deposited in a lagoon connected to the sea by an intermittently closing channel. [ABSTRACT FROM AUTHOR]

Investigations of abiotic and biotic contributions to dissolved organic carbon (DOC) are required to constrain microbial habitability in continental subsurface fluids. Here we investigate a large (101–283 mg C/L) DOC pool in an ancient (>1Ga), high temperature (45–55 °C), low biomass (102−104 cells/mL), and deep (3.2 km) brine from an uranium-enriched South African gold mine. Excitation-emission matrices (EEMs), negative electrospray ionization (–ESI) 21 tesla Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS), and amino acid analyses suggest the brine DOC is primarily radiolytically oxidized kerogen-rich shales or reefs, methane and ethane, with trace amounts of C3–C6 hydrocarbons and organic sulfides. δ2H and δ13C of C1–C3 hydrocarbons are consistent with abiotic origins. These findings suggest water-rock processes control redox and C cycling, helping support a meagre, slow biosphere over geologic time. A radiolytic-driven, habitable brine may signal similar settings are good targets in the search for life beyond Earth. A deep, ancient, and uranium-rich brine in South Africa reveals evidence of radiolytically oxidized kerogen and C1–C3 hydrocarbons with abiotic isotopic signatures that support a low biomass microbial community over time. [ABSTRACT FROM AUTHOR]

Sapropel was used as a biodegradable material for water treatment. Sapropel is a sedimentary layer of a mix of organic and inorganic substances accumulated in the bottoms of lakes for thousands of years. It is a jelly-like homogeneous mass and has properties of sorption. Sapropel is used as a biosorbent and an environment-friendly fertiliser, and it is used in building materials and in the beauty industry as well. In water, there are abundant various solutes that may cause a risk to human health. Such substances include fluorides, nitrates and lead in different sources of water. The goal of this investigation is to explore and compare the efficiencies of removal of different pollutants (fluorides, nitrates and lead) from aqueous solutions upon using sapropel as a sorbent. In this research, various doses of sapropel (0.1, 0.5, 1, 5, 10, 20, 50, 100 and 200 g/L) and various mixing times (15, 30, 60, 90 and 120 min) were used for removal of fluorides, nitrates and lead from aqueous solutions. It was found that the maximum efficiency (up to 98.57%) of lead removal from aqueous solutions by sapropel was achieved when the minimum doses of it (0.1 and 0.5 g/L) were used. The most efficient removal of fluorides (64.67%) was achieved by using 200 g/L of sapropel and mixing for 120 min. However, sapropel does not adsorb nitrates from aqueous solutions. [ABSTRACT FROM AUTHOR]

Taking the Zhongqiu 1 Gas Field in the Tarim Basin as an example, the heterogeneity of large-scale mono-block gas fields and their primary controlling factors have been analyzed. Based on drilling core data, well log data, scanning electron microscopy, thin-section analysis, and mercury injection experiments, combining sedimentological interpretation, research on the reservoir characteristics and variability was carried out. The results showed that: (1) The lithologic characteristics showed obvious variations among wells in the Zhongqiu 1 gas field. Specifically, the main lithology developed in the Zhongqiu 1 well is feldspar lithic sandstone, while the remaining wells predominantly consist of lithic feldspar sandstone. These differences in rock composition maturity reveal that a higher proportion of stable mineral components leads to poorer reservoir properties; (2) the main factors controlling oil and gas productivity include the variations in petrology, mineralogy, and diagenetic process characteristics. The high content of unstable mineral components and constructive diagenesis could increase reservoir porosity together. (3) Sedimentary facies of the Bashijiqike Formation in the Zhongqiu 1 Gas Field played a dominant role in the reservoir distribution. The division of sedimentary facies zones reflects variations in material composition and grain size, serving as the main material basis for reservoirs. Differences in mineral composition reflect the sedimentary environment of the reservoir. Additionally, mineral composition indicates the relationship between diagenetic processes and reservoir evolution. The high feldspar content in well ZQ1 corresponded to relatively favorable reservoir properties. The dominant feldspar type was plagioclase, suggesting that early-stage chemical weathering had undergone significant alteration. The above conclusions provided a microscopic perspective to explain the differences in oil and gas production capacity of large delta-front gas fields, serving as a geological basis for the exploration and exploitation of similar fields. [ABSTRACT FROM AUTHOR]

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

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency 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.)

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One year after the emergency diesel fuel spill in Norilsk, the hydrocarbon concentrations in bottom sediments of the Norilo-Pyasinsk water system decreased. However, the average decrease in the areas occurred in the same sequence (µg/g) as in 2020: the mouth of the Ambarnaya River (835, σ = 1788) > Bezymyannyi Creek–Daldykan River–Ambarnaya River (306, σ = 273) > the Pyasina River (23, σ = 20) > Pyasino Lake (12, σ = 8). The concentrations decreased due to degradation of low molecular weight hydrocarbons. The content of polycyclic aromatic hydrocarbons also changed in a smaller range (0–1027 ng/g) in 2021 than in 2020 (0–3865 ng/g). The petroleum origin of polycyclic aromatic hydrocarbons in the sediments of the Ambarnaya River (including the mouth), Bezymyannyi Creek, and the Daldykan River confirms the dominance of alkylated naphthalene homologs in their composition. Hydrocarbon accumulation in certain horizons of the sedimentary stratum is caused not only by seepage of diesel fuel, but also by the input of organic matter from the surrounding swamps and floodplain lakes, as well as by the burial of the surface layer by the 2021 flood. [ABSTRACT FROM AUTHOR]

The Muli permafrost area is the only midlatitude permafrost area where natural gas hydrates (NGHs) have been drilled. Although a series of achievements has been made in studies on NGH accumulation conditions in the permafrost area, related studies on gas hydrate stability zones, gas sources and groundwater are still controversial and need further work. Based on geophysical, geological and geochemical data, this paper systematically elaborates the main NGH accumulation conditions in the Muli area in terms of the pressure‒temperature stability conditions, fault structure, gas composition, gas source, reservoir characteristics, groundwater distribution and topographic characteristics. The results show that the thicknesses of the NGH stability zone range from 491.0 to 962.7 m. The fault structure can provide a pathway for hydrocarbon gas migration from deep to NGH stability zones, in which thrust faults can prevent the upwards migration of gas by sealing it below the hanging wall block. Rock fractures in the NGH stability zone can not only be gas migration channels, but also serve as a reservoir space for NGH accumulation. The hydrocarbon gas of NGHs shows multiple origins and is mainly composed of oil-associated gas. The formation of frost mounds related to the overpressured gas ejection caused by NGH decomposition may imply the existence of NGHs. Synthetically, similarities and differences in NGH accumulation conditions between the Muli permafrost area and other high-latitude permafrost areas are proposed, and the 'regression' NGH accumulation pattern in the Muli area is constructed. The study results can enrich theoretical knowledge of terrestrial NGH accumulation, and provide scientific guidance for NGH exploration in midlatitude permafrost areas. [ABSTRACT FROM AUTHOR]

Rock-thin section study, scanning electron microscopy (SEM), X-ray diffraction (XRD), and Rock-Eval pyrolysis have been carried out on the Barail (Oligocene) and Disang (Eocene) groups of rocks of the Naga Schuppen Belt of Assam-Arakan Basin to understand the reservoir properties and hydrocarbon source potential. Analyses show that the Barail Group sandstones are moderately well-sorted, medium-grained, sublithic arenite type, and bear good porosity (avg. 14.48%). In contrast, the Disang Group sandstones are very hard and compact, fine-grained, sublihic arenite, and lithic greywacke types and show medium porosity (avg. 11.3%). The reservoir properties of the sandstones of both groups are controlled by various diagenetic alterations like mechanical compaction, cementation, overgrowth, authigenesis of clay, fracturing, dissolution, and alteration of unstable clastic grains. However, no single diagenetic process could be considered as the main controlling parameter in the evolution of the porosity of the studied sandstones. The Rock-Eval pyrolysis indicates that the carbonaceous shales of both the Barail and Disang groups are characterized by type III and type IV kerogen. A good number of shale samples show TOC (total organic carbon) values ranging from 0.88 to 10.71 wt% which seems quite good. In most of the samples, S2 is recorded <2 mg HC/g of rock, indicating the potential to generate wet gas. The various binary plots mostly show the gas source potential of shales of both the Barail and Disang groups. Production Index (PI) values vary between 0.04–0.45 for the Barail shales and 0.04–1.0 for the Disang shales, indicating that the studied shale samples are in the last phase of catagenesis. [ABSTRACT FROM AUTHOR]

Sapropel is specific water body sediments containing a high level of organic matter formed from remains of water biota mixed with mineral components. One of the most promising utilisation ways of sapropel is agriculture where it can be used as soil amendment to improve soil physical properties and thus obtain economically viable and high quality yield of field crops. For three years the experiments were conducted at Priekuli Research Centre of the Institute of Agricultural Resources and Economics. Dehydrated sapropel mass from Lake Bizas was studied as soil biological fertilizer to determine its suitability for use in field crop production. Researches were carried out in organic crop rotation, in the fields of potato, winter rye and field bean. Three different doses of sapropel fertilizer were applied. During the three-year period (2020-2022), the yield indicators of the plant species included in the study were evaluated, and the quality of the yield of these species was assessed. The results of research confirm the positive effect of sapropel on yield quality indicators - protein (field beans), starch (potatoes) falling number and 1,000 seed mass (winter rye). [ABSTRACT FROM AUTHOR]

Sedimentary pyrite trace-element composition is an established proxy for determining paleo-ocean geochemistry and atmospheric oxygen concentrations through deep time. However, its applicability over shorter time-scales (i.e. <20 Ma) is not well known. To test this, we targeted fine-grained pyrite in the Hovea Member of the Kockatea Shale (Perth Basin, Western Australia), which encompasses the late Permian inertinitic interval and the end-Permian to Early Triassic sapropel, and spans approximately 10 million years. The end-Permian mass extinction (EPME) was the largest extinction event in Earth history, and its greatest effect is documented in the marine environment. Samples were collected from two oil exploration wells—Redback-2 and Hovea-3—spaced ∼20 km apart. In the two boreholes, a change in depositional facies (i.e. between the inertinite and sapropel) occurs below the Permian–Triassic boundary and records the transition from a marginal marine to a shelf environment. This transition is highlighted by several lithogeochemical indicators (e.g. negative shift δ13C values and Corg reduction; increases in Ca, Fe and P), which are themselves tied to fundamental changes in modal mineralogy between the two zones. Importantly, the sapropel also records a major increase in iron sulfide burial over that in the inertinite. LA-ICPMS analyses of pyrite demonstrate that trace-element abundance is highest in samples below the facies transition, and in places reaches a few percent, particularly of Ni (4 wt%), Co (1.5 wt%) and As (2.8 wt%). Moreover, these and other trace elements decrease by an order of magnitude in concert with the negative shift in δ13C values in the sapropel zone. Various whole-rock based paleosalinity indicator ratios (e.g. B/Ga) indicate that the areas of the Perth Basin intersected by Redback-2 and Hovea-3 were not fully connected to the open ocean at the time of the EPME, which leads us to conclude that the very high trace-element values in the sedimentary sulfides are reflective of regional environmental shifts rather than a global signal. Nonetheless, a geochemical contribution from a distant igneous province, such as the Siberian Traps Large Igneous Province, cannot be ruled out. Our work underscores the strength of sedimentary pyrite as a robust paleoenvironmental proxy in the marine environment and highlights the need for further investigation of pyrite trace-element profiles across the mass extinction interval in other sedimentary sequences around the globe. LA-ICPMS-based geochemistry of sedimentary pyrite from the Hovea Member of the Kockatea Shale is considered within a lithochemostratigraphic context. The overall interpretation of the results involves a change in depositional setting from the marginal in the late Permian brackish waters to shelfal marine and loss of oxygen in the Early Triassic Perth Basin. [ABSTRACT FROM AUTHOR]

The Kalumpang Formation was deposited in a delta plain setting. A Middle to Late Eocene age (Proxapertites operculatus zone) was inferred from palynological analysis, with a paleoenvironment in a coastal plain setting with a strong terrestrial influence. Samples from the Kalumpang Formation indicate a marginal to early mature stage for hydrocarbon generation. It is mostly composed of gas-prone to oil and gas-prone Type III kerogen facies. The biomarker character of both the rock and oil samples suggests a terrestrial origin, with a significant contribution of estuarine or bay organic material. The oil derives from a noncarbonate lithology, while the rock samples are from carbonate/calcareous shale origin. The abundance of oleanane compound and C30 resins suggests higher plant angiosperm input of Late Cretaceous or younger age for both the rock and the oil samples. The oil seep contains more abundant oleananes compared to the carbonaceous mudstone of the Kalumpang Formation. This suggests that the oil originated from more marine facies than the rock samples, which were deposited in a delta plain setting. This study demonstrated the agreement of depositional environment interpretation and age assessment between lithofacies, palynological, and organic geochemistry analysis. [ABSTRACT FROM AUTHOR]