A Baseline Survey of The Geochemical Characteristics of the Arctic Soils of Alexandra Land Within the Franz Josef Land Archipelago (Russia)

The composition of soils and their parent materials were studied within one of the most northern land areas of the world – the island of Alexandra Land of the Franz Josef Land archipelago. Contents of 65 trace and major elements were determined using atomic emission spectrometry (ICP-AES) и inductively coupled plasma spectrometry (ICP-MS). Other analyzed characteristics included soil pH, particle-size distribution and contents of carbon and nitrogen. The mineralogical composition of rocks was determined in thin sections. The studied soils were formed on basalts with high contents of MgO, Fe2O3, TiO2, Сu, Co, V, Ni, Cr, Zn, and low contents of Pb and Hg. The composition of soils was generally similar to that of the bedrock. The median concentrations (mg kg-1) of trace elements in the soils were as follows: Cu - 160, Zn - 101, Ni - 74, Pb - 2.9, Cd - 0.14, and Hg - 0.031. The bedrock had an alkaline pH, whereas the soil pH ranged from weakly acid to alkaline. The textural class of the soils predominantly corresponded to sandy loam. The contents of clay and silt increased with depth due to the migration of these fractions with groundwater. The concentrations of ecologically hazardous Hg and Pb were slightly increased in the upper layer of soils and correlated with carbon contents, which was indicative of bioconcentration processes.

Lab-Scale Permeability Enhancement by Chemical Treatment in Fractured Granite (Cornubian Batholith) for the United Downs Deep Geothermal Power Project, Cornwall (UK)

A hydrothermal doublet system was drilled in a fault-related granitic reservoir in Cornwall. It targets the Porthtowan Fault Zone (PTF), which transects the Carnmenellis granite, one of the onshore plutons of the Cornubian Batholith in SW England. At 5058 m depth (TVD, 5275 m MD) up to 190 °C were reached in the dedicated production well. The injection well is aligned vertically above the production well and reaches a depth of 2393 m MD. As part of the design process for potential chemical stimulation of the open-hole sections of the hydrothermal doublet, lab-scale acidification experiments were performed on outcrop analogue samples from the Cornubian Batholith, which include mineralised veins. The experimental setup comprised autoclave experiments on sample powder and plugs, and core flooding tests on sample plugs to investigate to what degree the permeability of natural and artificial (saw-cut) fractures can be enhanced. All samples were petrologically and petrophysically analysed before and after the acidification experiments to track all changes resulting from the acidification. Based on the comparison of the mineralogical composition of the OAS samples with the drill cuttings from the production well, the results can be transferred to the hydrothermally altered zones around the faults and fractures of the PTF. Core Flooding Tests and Autoclave Experiments result in permeability enhancement factors of 4 to >20 and 0.1 to 40, respectively. Mineral reprecipitation can be avoided in the stimulated samples by sufficient post-flushing.

Physical-Chemical Studies of the Process of Condensation of a Clinker-Free Binder

The possibility of using a clinker-free binder as an alternative to expensive and energy-intensive Portland cement is being considered. The pozzolanizing effect of volcanic rocks is presented, where along with the binding of calcium hydroxide by silica to hydrosilicates, the binding of calcium hydroxide by “free” alumina to hydroaluminates also takes place. In the process of hardening of the clinker-free binder, the phase mineralogical composition of the formed new formations differs from the new formations that are synthesized during hardening of traditional Portland cement, which explains the difference in their properties. The new formations that are formed during the hardening process of clinker-free cements are mainly low-basic hydrosilicates, and alkaline aluminosilicates give the cast-in-place stone water resistance, frost resistance, waterproofing, etc., in a word, durability. Physical and chemical studies of the hardening process of clinker-free lime-igneous cements have been carried out, which indicates the possibility of replacing the energy-intensive Portland cement with cheaper clinker-free cement.

The Potential for Lunar and Martian Regolith Simulants to Sustain Plant Growth: A Multidisciplinary Overview

Bioregenerative life support systems (BLSS) are conceived of and developed so as to provide food sources for crewed missions to the Moon or Mars. The in situ resource utilization (ISRU) approach aims to reduce terrestrial input into a BLSS by using native regoliths and recycled organic waste as primary resources. The combination of BLSS and ISRU may allow sustainable food production on Moon and Mars. This task poses several challenges, including the effects of partial gravity, the limited availability of oxygen and water, and the self-sustaining management of resources. Lunar and Martian regoliths are not available on Earth; therefore, space research studies are conducted on regolith simulants that replicate the physicochemical properties of extra-terrestrial regoliths (as assessed in situ by previous missions). This review provides an overview of the physicochemical properties and mineralogical composition of commercially available Lunar and Martian regolith simulants. Subsequently, it describes potential strategies and sustainable practices for creating regolith simulants akin to terrestrial soil, which is a highly dynamic environment where microbiota and humified organic matter interact with the mineral moiety. These strategies include the amendment of simulants with composted organic wastes, which can turn nutrient-poor and alkaline crushed rocks into efficient life-sustaining substrates equipped with enhanced physical, hydraulic, and chemical properties. In this regard, we provide a comprehensive analysis of recent scientific works focusing on the exploitation of regolith simulant-based substrates as plant growth media. The literature discussion helps identify the main critical aspects and future challenges related to sustainable space farming by the in situ use and enhancement of Lunar and Martian resources.

USE OF AGROMINERAL AS SUBSTRATE FOR GROWTH OF EUCALYPTUS SEEDLINGS

Success in the production of eucalyptus seedlings directly affects the development of plants in the field. Several factors influence their initial growth, especially the substrate. This study aimed to evaluate the growth of Eucalyptus globulus seedlings and characteristics of the substrate using silicate agromineral (SA) in different proportions (substrate:SA; v/v): T0 – 100:00%, T1 – 90:10%, T2 – 80:20%, and T3 – 50:50%. The treatments were evaluated using a completely randomized design. Measurements of height (H), stem diameter (SD) and calculation of the H/SD ratio of the plants were performed every 3 weeks, totaling 4 measurements. At the end of the experiment (12 weeks), soil fertility analyses, granulometric analysis (sand, silt and clay) and total chemical analysis were carried out. Due to the chemical and mineralogical composition of SA, its use in substrate in a greater proportion (T3) promoted the increase of exchangeable K, Ca and Si contents, which influenced the increase in the sum of bases and cation exchange capacity. The levels of assimilable P and micronutrients Fe, Cu, Zn and Mn were also higher in this treatment. The increase in SA proportions in the substrate composition also favored increase in the sand fraction and reduction in the clay fraction. As for the growth of seedlings, the results were not significant for H and SD as a function of SA doses, leading to the conclusion that the solubilization and slow release of nutrients by SA did not influence the growth of the plants

Geological and soil engineering properties of shallow landslides occurring in the Kutupalong Rohingya Camp in Cox’s Bazar, Bangladesh

The Forcibly Displaced Myanmar Nationals (FDMN), historically known as ‘Rohingya’ who fled the 2017 ethnic atrocities and genocide in the Northern Rakhine State of Myanmar, took shelter in Cox’s Bazar District of Bangladesh. The camp network, known as Kutupalong Rohingya Camp (KRC), is situated in the tectonically active tertiary hilly terrain. The KRC has been experiencing hydrometeorological hazards, where landslides are frequent. This study investigated the slopes’ geological condition, engineering properties and human interventions, which influence the landslides. The exposed slopes were relatively high (> 10 m) and steep ranging from 40° to 60° that have numerous polygonal tension cracks and fissures. From the geological and geotechnical aspects, there are three successive units of slope materials: (1) residual soils of sandy silt with clay, (2) highly weathered silty sandstones and (3) shale/clay with silt and fine sand intercalations at the bottom of the slopes. Field observations revealed that most slope failures occurred in the residual soil and weathered silty sandstone units. The residual soils have a bulk density of 1.49–1.97 g/cm3, a liquid limit of 25–48%, a plasticity index of 5–16% and an undrained shear strength of 23–46 kPa. The silty sandstones have a bulk density of 1.44–1.94 g/cm3, an internal friction angle of 34°–40° and a cohesion of 0.5–13 kPa. The mineralogical composition determined by the X-ray diffraction shows low clay mineral content, which does not affect landslides. However, the slope geometry, low shear strength with strain softening properties and torrential rainfall accompanied by anthropogenic factors cause numerous landslides every year. This study will help take proper mitigation and preparedness measures for slope protection in the KRC area and surroundings.

Rubber bark dust-zeolite composite improved mechanic strength of soft paddy soil through improved microstructure

<p>Soft paddy soils are not a stable soil structure that leads to the decline of rice production in Kedah, Malaysia. The soil had high compressibility and water content, and low soil strength thus the agricultural machines could not be operated above this soil. Therefore, this study was conducted to improve the mechanical strength of soft soils in paddy fields using an organic amendment. The organic amendment used in this study was made from amended materials comprising clinoptilolite, kieserite, humic acid, and rubber bark dust. The study was carried out in the paddy field area of Alor Pudak district, Kedah, Malaysia, and it was divided into five treatments of amendment dose, i.e: 0 kg (control or P0), 125 kg (P1), 250 kg (P2), 375 kg (P3) and 500 kg (P4) with each plot size about 0.20 ha. The soil samples were then analyzed using X-ray diffraction (XRD), scanning electron microscope (SEM), and the unconsolidated undrained triaxial compression test (UU-test) to characterize their amended properties. The XRD results clearly exhibited changes in the mineralogical composition of all treated plots with an increasing smectite content (1200 to 1300 intensity). Furthermore, the SEM results showed that clay particles in the treated plots have been flocculated to form close-knit, more stable soil structures. After the organic amendment application, the mechanical strength of the treated plots increased to an optimum level (50 kPa in P2) for resisting mechanical pressure from agricultural machinery. Overall, this study of the efficacy of organic amendment offers new insight into a soft paddy soil remediation method that is more effective and economical than the conventional method.</p>

Processing of Ogbolokuta limestone through calcination technique for quicklime production

Report on processing of Ogbolokuta limestone through calcination technique for quicklime production is presented. The limestone was washed to remove impurities, dried, ground in to powder form and classified with the aid of the automatic vibrating sieves of 80mm, 90mm, 100mm, 300mm and 425mm. X-ray fluorescence spectroscopy was used to determine the chemical compositions of the limestone, while its mineralogical composition was determined by X-ray diffractometer. Scanning electron microscope was used to study the surface morphology of the sample. Sample size area was grossly estimated by Langmuir method, while density functional theory was used to obtain different pore structural morphology of the sample. Analyses of the results showed that CaO (65.7%) is the predominant chemical constituent, and calcite is the main mineral of the limestone. Quicklime was successfully produced from Ogbolokuta limestone through calcination process. Calcination of the limestone enhanced its surface morphology. The quicklime yield was temperature, particle size and time dependent.

Processing of Yandev quicklime for potential amelioration of acidic soil

This study focused on processing of Yandev quicklime for potential amelioration of acidic soil. It involved production of quicklime from the Yandev limestone, characterization and slaking of the quicklime. In a batch process, 10g of the limestone (90mm particle size) was calcined for 3hrs to produce the quicklime. Mineralogical composition of the quicklime was determined by X-ray Diffractometer (XRD), while scanning electron microscope (SEM) was used to examine its surface morphology. The CaO was hydrated for the production of slaked lime (Ca (OH) 2). The slaking process was carried out by digesting CaO in distilled water. During the slaking/hydration process, values of reactivity (rise in temperature) were recorded. Central composite design (CCD) tool of Design Expert Software 11 was used to design the experiment of the slaking process. Quicklime/water ratio, particle size and time were the considered slaking variables, while reactivity was considered as the response. Analysis of the results quicklime is made up of pure calcite with visible pores. Quadratic model adequately described the relationship between reactivity and the considered slaking factors of quicklime/water ratio, particle size and time. Optimum reactivity was obtained as 58.4 0C with the corresponding optimal factors of quicklime/water ratio (0.26 g/ml), particle size (93.0 µm) and time (16.4 minutes). Properties of the slaked lime showed that it is suitable for acidic soil amelioration.