Secondary Accumulation Research Articles

Early crack resistance and life cycle assessment of seawater-mixed sintered sludge cement paste

Due to the accelerating effect of chloride and sulfate on the hydration of clinker, seawater-mixed cement (SC) paste is more prone to brittle cracking. Herein, this research systematically investigates the early crack resistance of seawater-mixed sintered sludge cement (SSSC) paste based on splitting tensile test and restrained squared eccentric ring test. The microstructure characteristics characterized by mercury intrusion porosimetry and scanning electron microscopy are combined to reveal the enhancement mechanism of sintered sludge ash (SSA) on SC paste, and a life cycle assessment is conducted around its carbon footprint. The results indicate that the SSA incorporation causes a continuous increase of 24.4 % in the splitting tensile strength of SSSC paste. Meanwhile, the digital image correlation technology accurately captures the strain and displacement fields composed of crack propagation, which tends to be symmetrically distributed and reduces the crack width by 30 %. During the inhomogeneous restrained shrinkage process, as the SSA increases, the crack deviation of the SSSC paste first magnifies and then reduces, the crack width decreases, and the cracking time extends. The pozzolanic activity of SSA is more active in SC paste, which significantly promotes the secondary accumulation of C-S-H and the increase of gel pore volume. This effectively reduces the risk of brittle cracking caused by uneven distribution of paste stiffness due to hydration acceleration during seawater mixing. In addition, replacing 50 % cement with SSA only results in a total of 4.1 % carbon emissions in SSSC paste and a 47.8 % reduction in global warming potential from sludge transportation to activation treatment, demonstrating significant environmental advantages.

The effect of thidiazuron (TDZ) enhances shoot organogenesis, in-vitro flowering, and secondary metabolism accumulation of Oldenlandia umbellata L. leaf explants

The effect of thidiazuron (TDZ) enhances shoot organogenesis, in-vitro flowering, and secondary metabolism accumulation of Oldenlandia umbellata L. leaf explants

Bilateral Subretinal Fluid Accumulation during Erdafitinib Therapy

Abstract Fibroblast growth factor receptor (FGFR) plays a major role in maintaining retinal pigment epithelium cells. Drugs that inhibit the FGFR pathway block the activation of the mitogen-activated protein kinase pathway, leading to the synthesis of antiapoptotic proteins and secondary subretinal fluid accumulation. Erdafitinib, a potent tyrosine kinase inhibitor of fibroblast growth factor receptors (FGFRs) is one such antitumour drug that has shown significant efficacy in patients with urothelial carcinoma with FGFR alterations. We present a case report demonstrating the bilateral subretinal fluid accumulation due to erdafitinib.

Cholecystohepatic shunt pathway reduces secondary bile acid accumulation to enhance natural killer T cell-mediated anti-hepatocellular carcinoma immunity.

The impact of cholecystectomy, which blocks the cholecystohepatic shunt pathway (CHSP), on the prognosis of patients with hepatocellular carcinoma (HCC) is unclear. Hepatic secondary bile acids (BAs) inhibit natural killer T (NKT) cell-mediated immunity against HCC, and the regulation of homeostasis of hepatic secondary BAs is controlled by the CHSP. However, the influence of CHSP on NKT cell-mediated immunity against HCC remains unclear. The clinical data of hospitalized patients undergoing HCC resection were collected. Meanwhile, an in situ HCC mouse model was established, and the CHSP was augmented using oleanolic acid (OA). After 1:1 propensity score matching, Cox regression analysis revealed that cholecystectomy was an independent risk factor for HCC recurrence after hepatectomy (P=0.027, hazard ratio: 1.599, 95% confidence interval: 1.055-2.422). Experimentally, when OA enhanced CHSP, a significant decrease was observed in the accumulation of secondary BAs in the livers of mice. Additionally, a significant increase was observed in the levels of C-X-C ligand 16 and interferon γ in the serum and tumor tissues. Further, the percentage of C-X-C receptor 6 (+) NKT cells in the tumor tissues increased significantly, and the growth of liver tumors was inhibited. This clinical study revealed that cholecystectomy promoted the recurrence after radical hepatectomy in patients with HCC. Preserving the normal-functioning gallbladder as much as possible during surgery may be beneficial to the patient's prognosis. Further investigation into the mechanism revealed that CHSP enhanced NKT cell-mediated immunity against HCC by reducing the hepatic accumulation of secondary BAs.

Black soils in the southwest of the Brazilian Pantanal: Organic carbon and secondary carbonates accumulation in Phaeozems–Gleysol-Chernozem

The southwest of the Brazilian Pantanal contains areas formed by calcareous sediments, which give this hydromorphic environment special characteristics in the formation of soils such as Phaeozems, Chernozems and Gleysols. These soils have a dark surface horizon, enriched with organic matter, high natural fertility in the sorption complex and high clay activity. These soils are important because they store large amounts of organic carbon and can be used in carbon sequestration and greenhouse gases studies. However, despite their abundance in the Pantanal region and importance, these soils are few studied. Thus, our study aimed to characterize the morphology, physical, and chemical attributes of black soils in this region, identifying the main mechanisms of organic carbon and secondary carbonate accumulation. Three profiles located in the municipality of Corumbá-MS were studied, namely Phaeozem (profiles P1), Gleysol (profile P2) and Chernozem (profiles P3). In all profiles, high concentrations of Ca2+, Mg2+ and K+ elements were observed, mainly derived from the sediments of the Serra da Bodoquena and the Urucum-Amolar residual plateau, ion transport fluxes and secondary carbonate dissolution. The preservation of these elements and 2:1 clays is closely linked to the rainfall dynamics of the region, alternating between floods and droughts. The high 2:1 clays and exchangeable Ca2+ benefits the stabilization of organic carbon by means of organic–mineral interactions and promote the increase of humin content. In Phaeozem and Chernozem, the highest levels of secondary carbonates were observed at the top of the B horizons of these soils, where the pressure of CO2 is lower. Being a lowland area under the direct influence of flooding, the development of secondary carbonates is limited in the B horizons of the Gleysol, where access to the water table and root activity at depth increases the CO2 pressure and hinders the re-precipitation of carbonates in this soil, precipitating in the capillary bangs and in the upper zone (surface horizons).

Biogenic carbonates (queras) in loess-palaeosol sequences of the Ebro Basin and their potential use as a palaeoenvironmental proxy

Secondary carbonate accumulations are very common in arid and semi-arid soils but are often poorly described and classified. This is the case for queras that are observed in several loess-palaeosol sequences of the Ebro Basin. Micromorphologically, queras are complex pedogenic features basically consisting of infillings of calcified root cells in channels, surrounded by decarbonated hypocoatings. They apparently result from biologically mediated calcification/decalcification processes at a microscale. The aim of this study is to systematically characterize biocalcifications found in dated loess-palaeosol sequences, to determine the main factors of formation, and to discuss their possible use as a palaeoenvironmental proxy. Different queras show a similar number of biosparite layers (four to five) around a central channel, and a decarbonated hypocoating around the queras. This supports the hypothesis that queras originate from the calcification of root tips and are related to the acidification of surrounding soil for nutrient absorption. Under cathodoluminescence microscopy, biosparite has a different behaviour than non-biological calcite crystals: the latter appears reddish while biosparite remains black. The queras, with ages corresponding to Marine Isotope Stages 1–3, are younger than that of the loess where they are found in. The stable isotope values likely correspond to C3 plants, and the estimated temperatures of formation reflect a Mediterranean temperate climate. This suggests that the biocalcifications developed during short moist seasons amidst arid periods of the Quaternary.

Research on fault-controlled hydrocarbon accumulation in rifted lacustrine basins based on structural geological modeling: a case study of the Banqiao area in Bohai Bay Basin, China

The Banqiao area in the Bohai Bay Basin has experienced three stages of extensional deformation, leading to the formation of numerous fault-bound traps. Faults, acting as boundary conditions for these traps, play a crucial role in hydrocarbon accumulation. In this study, we conducted a 3D structural modeling of the area using high-resolution 3D seismic data and established a fault-reservoir database based on previous research. Our findings reveal four levels of faults in the Banqiao area: basin-controlling faults, boundary faults, derivative master faults, and secondary adjusting faults. The structural units can be categorized into subsag areas, slope areas, stress tran-sition zones, bifurcation and main incised fault zones, and southern block areas. The segmented growth of the main boundary faults controls the evolution of the subsags, with the subsidence center gradually shifting eastward from Rift Phase I to Rift Phase II, aligning with the distribution of source rocks. Fault-bound traps in the Banqiao area include single faults, intersecting faults, and side faults. Faults primarily act as barriers to lateral hydrocarbon migration during the process of hydrocarbon accumulation, while also providing pathways to a lesser extent. By integrating the fault-reservoir database with the fault system classification, we identified four types of fault-controlled hydro-carbon accumulation models: like-dipping fault barrier model, oppositely-dipping fault barrier model, intersecting fault barrier model, and reactivation-controlled secondary hydrocarbon ac-cumulation model. This structural geological model effectively demonstrates the spatial configura-tion of faults and their role in hydrocarbon accumulation in the Banqiao area. The fault control mechanisms presented in the model can also be applied to other blocks in the Bohai Bay Basin, laying a foundation for future petroleum exploration in continental rifted basins and facilitating the ap-plication of big data algorithms in various geoscientific research fields.

In vitro morphogenesis, antioxidant enzyme activity and secondary compound accumulation of Phyllanthus amarus under Clinostat 2D condition

In this study, 4-week-old internodes of in vitroPhyllanthus amarus with 1 cm in length were cut in a half longitudinal section and cultured under 2D clinostat and control conditions to evaluate in vitro morphogenesis, antioxidant enzyme activity and secondary compound accumulation. The results showed that 34.33% of explants induced callus and 65.67% of explants formed adventitious root under 2D clinostat compared with 100% explants induced callus under control after 4 weeks of culture. In addition, the fresh and dry weights of callus clusters (792.00 and 79.17 mg, respectively) under 2D clinostat were higher than those under control (313.33 and 30.07 mg, respectively). Superoxide dismutase (SOD), catalase (CAT), and phenolic under 2D clinostat were higher than those of control. For hypophyllanthin and phyllanthin, the concentrations in the callus under 2D clinostat condition were higher than control. The hypophyllanthin content in the callus (29.06 μg/g fresh weight) was higher than in the adventitious root (9.03 μg/g fresh weight) under 2D clinostat, while the phyllanthin only obtained in the callus that was absent in the adventitious root.

Paleosol distribution and morphology along a late Cretaceous distributive fluvial system in the Bauru Basin, Brazil

Distributive Fluvial Systems (DFS) are fan-shaped landforms constituted by a radial system of channels that diverge downstream from an active apex, where the drainage emerges from the confinement valley. In such landforms, elevation, distance from fluvial channels, sedimentation rates, surface stability, and plant cover control weathering processes and soil development, but these features are obliterated within geological time. Thus, the micromorphological analysis of paleosols can be helpful for paleoenvironmental reconstruction of ancient DFS, improving the knowledge of soil genesis in these depositional landforms. Here, we describe macro and micromorphological features of twenty paleosols developed under arid to semiarid climates along the proximal to the medial zone of an Upper Cretaceous DFS in the Marília Formation, Bauru Basin, Brazil. Paleosols on the proximal zone typically showed features consistent with poor drainage, namely Bg, Btg and Bss horizons, and reddish Bt horizons in higher positions. Conversely, paleosols on the medial zone commonly showed reddish colours and pronounced secondary carbonate accumulation, consistent with a predominantly arid climate. Based on this distribution, we elaborated an evolution landscape model for the proximal and medial zone of the Bauru DFS, including allogenic and authigenic controls of soil development during the Campanian to the Maastrichtian epochs of southeastern Brazil.

Identification of GM1-Ganglioside Secondary Accumulation in Fibroblasts from Neuropathic Gaucher Patients and Effect of a Trivalent Trihydroxypiperidine Iminosugar Compound on Its Storage Reduction.

Gaucher disease (GD) is a rare genetic metabolic disorder characterized by a dysfunction of the lysosomal glycoside hydrolase glucocerebrosidase (GCase) due to mutations in the gene GBA1, leading to the cellular accumulation of glucosylceramide (GlcCer). While most of the current research focuses on the primary accumulated material, lesser attention has been paid to secondary storage materials and their reciprocal intertwining. By using a novel approach based on flow cytometry and fluorescent labelling, we monitored changes in storage materials directly in fibroblasts derived from GD patients carrying N370S/RecNcil and homozygous L444P or R131C mutations with respect to wild type. In L444P and R131C fibroblasts, we detected not only the primary accumulation of GlcCer accumulation but also a considerable secondary increase in GM1 storage, comparable with the one observed in infantile patients affected by GM1 gangliosidosis. In addition, the ability of a trivalent trihydroxypiperidine iminosugar compound (CV82), which previously showed good pharmacological chaperone activity on GCase enzyme, to reduce the levels of storage materials in L444P and R131C fibroblasts was tested. Interestingly, treatment with different concentrations of CV82 led to a significant reduction in GM1 accumulation only in L444P fibroblasts, without significantly affecting GlcCer levels. The compound CV82 was selective against the GCase enzyme with respect to the β-Galactosidase enzyme, which was responsible for the catabolism of GM1 ganglioside. The reduction in GM1-ganglioside level cannot be therefore ascribed to a direct action of CV82 on β-Galactosidase enzyme, suggesting that GM1 decrease is rather related to other unknown mechanisms that follow the direct action of CV82 on GCase. In conclusion, this work indicates that the tracking of secondary storages can represent a key step for a better understanding of the pathways involved in the severity of GD, also underlying the importance of developing drugs able to reduce both primary and secondary storage-material accumulations in GD.

Assessment of the depositional characteristics of the Yellow River estuary from 1960s by 239+240Pu and 137Cs

The spatial and vertical distribution of 239+240Pu and 137Cs in the sediments of the Yellow River Delta was studied to evaluate the deposition dynamics in the Yellow River estuary from 1960s. The activity of 239+240Pu and 137Cs in sediment core ranged from 0.001 to 0.212 Bq/kg and 0.52–2.53 Bq/kg, respectively. A maximum accumulation peak and two secondary accumulation peaks appeared in the sediment core YR2. The average deposition rate of 8.3 cm/y for the Yellow River estuary from 1964 to 1976 was obtained. The proportion of Pu from the Yellow River net input and direct deposition to the total inventory of Pu in the estuary was assessed, with a total inventory of Pu in the abandoned estuary of 7.4 × 1010 Bq and a net input of 2.2 × 1010 Bq from the Yellow River. Pu deposited in the estuary only accounts for 18 % of the total Pu transported by the Yellow River, and most of the Pu is injected into the Bohai Sea with the Yellow River.

Involvement of miRNAs regulation on both flower development and secondary metabolism in Lonicera japonica Thunb.

Lonicera japonica Thunb. is a famous healthy resource of both medicine and food. The flower of L. japonica is widely used in health tea and beverages industries. Although the accumulation mechanism of active ingredients during the flowering process has attracted numerous studies, the regulatory function of miRNAs, at post transcriptional modification level, has not been deeply investigated. In this study, miRNAs from floral stages were sequenced and functionally analyzed by means of obtained transcriptomic and metabolomic data. Totally 234 differentially expressed miRNAs were identified and significant expression correlation was observed between 182 target genes and 83 associated miRNAs. The constructed correlation network demonstrated Car-miRN777 might perform broad regulation effects on RNA, protein, lipid metabolism, transport, and secondary metabolism. The target genes belonging to RNAs showed a gradual decrease during the flower development. It was further proved that Car-miRN777 and miR319a targeted ELF7/CPK33 and MYB33/TCP4, respectively, regulating the flowering process. Additionally, miR160I and miR482d targeting ADT and MYB1, respectively, might mediate the upstream and downstream fluxes of phenylalanine for anthocyanin formation. Taken together, this study identified potential miRNAs regulating flowering process and secondary metabolic accumulation during floral stages, which could promote the industrial development of high-quality food resources of L. japonica.

An integrated chemical approach for the removal of hazardous Cr(VI) and other contaminants of tannery wastewater: Biopolymer-assisted adsorption separation and conversion into valuable materials

To counter the toxic effects of Cr(VI) ions in industrial wastewater, adsorption onto a suitable adsorbent is prudent, but the resulting secondary waste accumulation and cleaning are challenging. Herein, biocompatible alginic acid has demonstrated selective adsorption of Cr(VI) ions with the subsequent conversion of the secondary waste into valuable materials. The maximum sorption was found to be 143 mg/g, and the adsorption follows the Langmuir model and pseudo-second-order kinetics. The process was tested with a simulated tannery effluent where selective Cr(VI) adsorption was achieved, and the secondary waste was converted to Cr2O3 and ZnCrO4. The remaining ions present Na+, Cl+, SO42- have been consolidated into an apatite mineral with the molecular formula of Ca4.1Na0.9(P0.7S0.3O4)3Cl. Overall, our integrated process of removing and converting Cr(VI) ions into beneficial by-products opens up a window of opportunities for large-scale water purification and industrial applications.

Fate and migration of enhanced rock weathering products through soil horizons; implications of irrigation and percolation regimes

Terrestrial enhanced rock weathering (ERW) is reckoned as a robust method to contribute to stabilizing atmospheric carbon and combat global warming. The method is particularly a matter of interest in agricultural soil, offering a vast opportunity for the application of crushed silicate minerals and secondary carbonate accumulation and migration. Although the applicability of this practice is well acknowledged, its impact on the geochemical alteration of soil vertical profile, particularly deeper layers, is less discussed in the literature. Moreover, the effect of irrigation and percolation regimes, as influenced by ambient conditions, is also not well-reported and characterized. In the present study, we utilized a high amendment rate (50 t/ha) of wollastonite skarn, a fast-weathering silicate mineral, to uncover the alterations in topsoil and subsoil as well as effluent water over a through a soil column experiment over five months, under more controlled (indoor) and less controlled (outdoor) ambient and irrigation conditions. The results indicate more conspicuous modification of parameters in shallow layers of soil compared to deeper ones, explicitly in the rain-fed setup. Silicate amendment induced an increase of 6.53 and 2.85 tCO2/ha (in the form of pedogenic carbonate (PC)) over the profile of soil (0–60 cm) under periodic and rain-fed water regimes, respectively. The silicate treatment was also found to be effective toward rising pH and electrical conductivity of topsoil (0–15 and 15–30 cm layers) and leachate, and a measurably greater release of Ca2+ and Mg2+ in the column effluent. We estimate a carbon drawdown ratio (carbonate/bicarbonate) of ≈15:1 in this study, showing that PC formation is a more significant weathering indicator than leachate bicarbonate export in the shorter term for a fast-weathering mineral in pH-neutral soils and moderate irrigation regime. Such observations are valuable for developing carbon drawdown quantification methods suitable for a variety of agricultural lands and global regions.

A Study on Avalanche-Triggering Factors and Activity Characteristics in Aerxiangou, West Tianshan Mountains, China

Through analyzing the triggering factors and activity characteristics of avalanches in Aerxiangou in the Western Tianshan Mountains, the formation and disaster-causing process of avalanches were studied to provide theoretical support and a scientific basis for avalanche disaster prevention. In this paper, based on remote sensing interpretation and field investigation, a spatial distribution map of avalanches was established, and the induced and triggering factors in disaster-prone environments were analyzed using the certainty factor model. The degree of influence (E) of the disaster-causing factors on avalanche triggering was quantified, and the main control conditions conducive to avalanche occurrence in different periods were obtained. The RAMMS-avalanche model was used to analyze the activity characteristics at points where multiple avalanches occurred. Research results: (1) The E values of the average temperature, average snowfall, and surface roughness in February were significantly higher than those of other hazard-causing factors, reaching 1.83 and 1.71, respectively, indicating strong control. The E values of the surface cutting degree, average temperature, and average snow depth in March were all higher than 1.8, indicating that these control factors were more prominent than the other factors. In contrast, there were four hazard-causing factors with E values higher than 1.5 in April: the mean temperature, slope, surface roughness, and mean wind speed, with clear control. (2) Under the influence of the different hazard-causing factors, the types of avalanches from February–April mainly included new full-layer avalanches, surface avalanches, and full-layer wet avalanches. (3) In the RAMMS-avalanche simulation test, considering the deposition effect, compared to the previous avalanche movement path, the secondary avalanche flow accumulation area impact range changes were slight, while the movement area within the avalanche path changes was large, as were the different categories of avalanches and their different movement characteristic values. Overall, wet snow avalanches are more hazardous, and the impact force is larger. The new snow avalanches start in a short period, the sliding rate is fast, and the avalanche sliding surface (full-snow surface and face-snow) of the difference is mainly manifested in the differences in the value of the flow height.

Evaluating the impact of the Central Chile Mega Drought on debris cover, broadband albedo, and surface drainage system of a Dry Andes glacier

In recent years, Chile has experienced an extraordinary drought that has had significant impacts on both the livelihoods of people and the environment, including the Andean glaciers. This study focuses on analyzing the surface processes of Universidad Glacier, a benchmark glacier for the Dry Andes. Multiple remote sensing datasets are used alongside a novel spectral index designed for mapping of rock material located on the glacier's surface. Our findings highlight the precarious state of the glacier, which serves as a crucial water source for the region. The glacier exhibits locally varied debris accumulation and margin retreat. The most significant impacts are observed on the tongue and secondary accumulation cirques, with the latter at risk of disappearing. The debris cover on the tongue is expanding, reaching higher elevations, and is accompanied by glacier retreat, especially at higher altitudes. The equilibrium line is rapidly shifting upglacier, although the mid-season snow cover still frequently reaches the 2013 equilibrium line, even in 2020. Changes in stream density on the glacier tongue indicate an increased water supply in this area, likely due to enhanced melting of glacial ice. These observed processes align well with meteorological data obtained from reanalysis products. The behavior of dust and debris is influenced by precipitation amount, while the rate of retreat is linked to air temperature.

The transformation and accumulation mechanism of rare earth elements in deep-sea sediments from the Wharton Basin, Indian Ocean

Recently, rare-earth elements and yttrium (REYs, including La-Lu and Y) have been found to be remarkably enriched in Pacific and Indian Ocean deep-sea sediments, as the extreme enrichment of critical metals have received unprecedented attention. However, the origins, transformation and accumulation mechanism of REYs in deep-sea sediments remain controversial. In this study, the mineralogical and geochemical characteristics of REY-rich sediments from the Wharton Basin, Indian Ocean (core GC34) were systematically analyzed. Our results indicate that bioapatites are the most significant host phase of REYs, ambient solutions (seawater and pore water) are the main sources of REYs in deep sea sediments. Besides being the other important host phase of REYs, Fe-Mn micronodules also act as the links between sources and sinks of REYs in deep-sea sediments. Based on the variations in the characteristic profiles of ΣREY, δCe, and MREE/MREE* with depth, combined with the fractionation characteristics of LREE, MREE and HREY in bulk sediments, bioapatites, and Fe-Mn micronodules, we present a model of REYs transformation and accumulation processes in the deep-sea sediments, which mainly occurs in two intervals. The first and dominant accumulation process is in the sediment–water interface (SWI) and shallow sediments, where Fe-Mn micronodules and bioapatites adsorb and/or substitute REYs directly from ambient solutions, resulting in the initial accumulation of REYs in bioapatites and micronodules. The secondary accumulation process in the deep subsurface sediments, due to desorption and resorption processes in bioapatites and release processes in micronodules. The significant connection between P/Th and ΣREY suggests that the physical enrichment of REY-rich materials (bioapatites and micronodules) contributed to the REYs enrichment in deep-sea sediments.

Stress in plant and their benefits for the secondary compound accumulation: a review

In recent years, crops have often experienced an increasing number of abiotic and biotic stresses, which significantly impair their growth and output due to global warming and accompanying climatic irregularities. Many studies have been carried out to improve plants' stress tolerance, including using fertilizers, microbial interactions, plant growth regulator application, and other methods. However, stress's role in improving a plant's ability to create a variety of secondary compounds such as phenolic acid, flavonoids, and anthocyanins, some of which have been linked to antioxidant activity and positive impacts on health, has yet to be well investigated. This review aims to summarize the potential for stress concerning the use of secondary compound content in plants.

Controls on Barite (BaSO4) Precipitation in Unconventional Reservoirs.

Barite (BaSO4) precipitation is one of the most ubiquitous examples of secondary sulfate mineral scaling in shale oil and gas reservoirs. Often, a suite of chemical additives is used during fracturing operations to inhibit the accumulation of mineral scales, though their efficacy is widely varied and poorly understood. This study combines experimental data and multi-component numerical reactive transport modeling to offer a more comprehensive understanding of the geochemical behavior of barite accumulation in shale matrices under conditions typical of fracturing operations. A variety of additives and conditions are individually tested in batch reactor experiments to identify the factors controlling barite precipitation. Our experimental results demonstrate a pH dependence in the rate of barite precipitation, which we use to develop a predictive model including a pH-dependent term that satisfactorily reproduces our observations. This model is then extended to consider the behavior of three major shale samples of highly variable mineralogy (Eagle Ford, Marcellus, and Barnett). This data-validated model offers a reliable tool to predict and ultimately mitigate against secondary mineral accumulation in unconventional shale reservoirs.

A closer look at clasts and groundmass: Micromorphological features in sediments with archaeological significance in Obishir and Katta Sai complexes (Central Asia)

The aim of this study is to investigate the relationship between coarse and fine material in sediments at four archaeological sites in Central Asia, which share a common characteristic of coarse clasts dispersed within a silty matrix. By using micromorphology and grain size analysis, the study aims to understand the microscale processes that have affected the geogenic material and, by extension, the potential impact on the archaeological assemblages. The four sites studied are Obishir-1, Obishir-5, Katta Sai 1, and Katta Sai 2, which are located at the toe or along a slope in Kyrgyzstan and Uzbekistan. The study focuses on the micro-features occurring on the surfaces of pebble-sized clasts and identifies four typical features: loamy cappings, loamy coatings, secondary calcium carbonate accumulations, and cracks. The processes related to these features are identified as alteration of the mineral grains, frost action, redeposition, and pedogenetic and anthropogenic processes. The study concludes that the primary contact between the two components has been disrupted in most cases, and suggests that the findings can be used to analyze site formation and post-depositional processes at archaeological sites. Furthermore, analogies with gravel-sized artifacts can be drawn, particularly with regard to secondary calcium carbonate accumulation.