High Strontium Content Research Articles

Structural studies and exchange bias interaction in Sr+2 doped LaFeO3 synthesised via PVA based sol-gel method

Modification in the crystal structure often exhibits different functionalities and characteristics. In the present study it is demonstrated that Sr2+ modified lanthanum ferrite La(1-x)SrxFeO3 (x = 0, 0.02, 0.04 and 0.06) prepared using PVA based sol gel method shows unique structure and magnetic properties. Structural analysis and phase formation study was performed using X-ray diffraction data and various structural parameters were calculated using Rietveld refinement. It is observed that with the increase in Sr2+ content the structural parameters of LaFeO3 unit cell change. The FESEM and TEM studies were used to study the size and morphology of La(1-x)SrxFeO3 nanoparticles. Magnetic hysteresis measurement reveals the appearance of zero field cooled exchange bias in La(1-x)SrxFeO3, originating due to the interfacial exchange coupling between AFM/FM. In addition, the magnetization increases while exchange bias vanishes at higher strontium concentration. These results help in understanding the in-depth interfacial coupling interaction mechanism.

Electrotransport in the La2NiO4-based solid solutions

Abstract This work combines new and earlier obtained results on electron hole and oxygen-ion transport in the La2NiO4-based solid solutions. The effect of lanthanum substitution with Ca/Sr and nickel with Fe, Mn, Co or Cu on transport properties of La2− x A x Ni1− y Me y O4+δ was analyzed and discussed at different substitution levels. Besides the changes in concentration and mobility of electron holes induced by the doping with cations of different nature, the partial transformation of Ni3+ from low-spin to high-spin state was shown to have a profound effect on transport properties of these materials leading to a notable decrease in mobility of electron holes, especially in the strontium-rich oxides. The obtained results suggested that the size factor was the main driving force behind the observed transformation of Ni3+. The oxygen-ion transport in La2− x A x Ni1− y Me y O4+δ was characterized by significant surface exchange limitations, which can be reduced only at relatively high concentrations of strontium and iron, and should be taken into account while evaluating the ionic conductivity by means of oxygen permeation or the modified Hebb-Wagner polarization method.

Local structure of relaxor ferroelectric SrxBa1−xNb2O6 from a pair distribution function analysis

Pair distribution function analysis of neutron-scattering data and of ab initio molecular dynamics results have been employed to study short-range structural correlations and their temperature dependence in a heavily disordered dielectric material ${\mathrm{Sr}}_{x}{\mathrm{Ba}}_{1\ensuremath{-}x}{\mathrm{Nb}}_{2}{\mathrm{O}}_{6}\phantom{\rule{4pt}{0ex}}(x=0.35,\phantom{\rule{0.28em}{0ex}}0.5$, and 0.61). Intrinsic disorder caused by a partial occupation of the cationic sites by differently sized Sr and Ba atoms and their vacancies introduces important local strains to the structure and directly influences the Nb-${\mathrm{O}}_{6}$ octahedra tilting. The resulting complex system of tilts is found to be both temperature and Sr-doping sensitive with the biggest tilt magnitudes reached at low temperatures and high strontium contents, where ferroelectric relaxor behavior appears. We find evidence for two Nb-${\mathrm{O}}_{6}$ subsystems with different variations of niobium-oxygen bond lengths, distinct dynamics, and disparate levels of deviation from macroscopic polarization direction. These findings establish a detailed picture of the local structure of ${\mathrm{Sr}}_{x}{\mathrm{Ba}}_{1\ensuremath{-}x}{\mathrm{Nb}}_{2}{\mathrm{O}}_{6}$ and provide a deeper insight into the origins of the materials dielectric properties.

In vitro Response of Human Osteoblasts Cultured on Strontium Substituted Hydroxyapatites

The goal of this study was to analyze the response of osteoblasts cultured on strontium substituted hydroxyapatites (HAP-Sr) of well-defined high crystallinity deposited as thin films on glass plates. Up to now, this aspect has not been carefully investigated in the context of bio-ceramics. In this study, we present the osteoblasts activity on synthesized HAP-Sr for different amounts of strontium substitution for calcium within the hydroxyapatite (Ca10(PO4)6(OH)2, HAP) lattice, namely HAP-5%Sr, HAP-10%Sr, HAP-15%Sr and HAP-59.2%Sr (Sr-HAP, of formula Sr10(PO4)6(OH)2), in comparison with stoichiometric pure HAP, chosen as control. Each bio-ceramic was deposited as thin multilayers self-assembled substrate (scaffold) and chemically bonded to the surface of glass plates. These coatings revealed by AFM and SEM imaging a granular texture formed from bio-ceramic nanoparticles. They possessed a high degree of crystallinity, i.e. 68% to 86%, depending on the Sr amount within the HAP lattice, as judged by XRD. Osteoblasts were cultured up to 21days and displayed enhanced adhesion and proliferation particularly evidenced on relatively high strontium contents (especially 5 and 10 weight %, determined by SEM-EDX), where the alkaline phosphatase activity and type I collagen were strongly evidenced. These bio-ceramics showed a high in vitro biocompatibility stimulating the activity of osteoblasts in the process of bone formation. These nano biomaterials can have applications in orthopedic and dental surgery improving the osteointegration as coatings of bone implants as well as for bone repair and regeneration.

Geochemistry of strontium in fresh underground waters of the Sredneobskoy basin (Tomsk region, Russia)

In the central part of Western Siberia a study of the chemical composition of fresh underground waters in the upper 600 m of the Sredneobskoy artesian basin was carried out. It was shown that underground waters generally contain high concentrations of strontium. The minimum concentrations of Sr are typical for Neogene-Quaternary sediments (600 µg/L), maximum values in the waters of the Upper Cretaceous sediments (more than 1300 µg/L). The study of strontium accumulation mechanisms in drinking underground waters is undoubtedly an important issue, as strontium is a biologically active element. Especially dangerous is the consumption of underground waters with a calcium-strontium ratio less than 100, that is the hydrogeochemical precondition for Urov endemic (Kashin-Beck disease). According to the calcium/strontium ratios data waters of the Neogene-Quaternary and Paleogene sediments selected in the south-western part of the Tomsk region are unsuitable for drinking water supply. Underground waters are shown to be in equilibrium with Al and Fe hydroxides; Ca, Mg, Fe carbonates; and clay minerals, including ferruginous. Increased strontium content in aquifers is determined not only by the chemical composition of the water-bearing rocks, but also increasing resident time of water rock interaction.

Strontium Alleviates Endoplasmic Reticulum Stress in a Nonalcoholic Fatty Liver Disease Model.

The purpose of this study was to explore the effects of strontium on fatty liver, and to clarify the possible mechanisms by which strontium improves nonalcoholic fatty liver disease (NAFLD). We also evaluated how strontium affected the endoplasmic reticulum stress (ERS) pathways. We established an in vitro model of NAFLD using a human hepatocyte cell line (L02) treated with 0.2 mM palmitic acid. The Sprague-Dawley rats were fed with a high-fat diet (HFD) to establish NAFLD model in vivo. After strontium treatment, the total cholesterol (TC), triglyceride (TG), and lipid deposition in L02 cells and liver tissues were determined. Strontium treatment suppressed intracellular TC and TG levels and lipid accumulation in L02 cells, and the effect of high concentrations of strontium were more obvious. Strontium significantly reduced the mRNA and protein expression of glucose-regulated protein 78 (GRP78), activating transcription factor 6 (ATF6), inositol requiring enzyme 1 (IRE1), SREBP cleavage activator protein (SCAP), sterol regulatory element binding protein 1c (SREBP-1c), and SREBP-2 in L02 cells. In HFD-fed rats, strontium treatment reduced serum TC, TG, and low density lipoprotein cholesterol (LDL-C) levels, concurrent with a decrease in hepatic lipid accumulation. Furthermore, strontium treatment reduced the expression of GRP78 and SREBP-2 protein in liver tissues. Overall, strontium alleviated hepatic steatosis by decreasing ERS-related protein expression in vivo and in vitro models. The results indicated that strontium has the potential to become a new therapy for the prevention and treatment of NAFLD.

STRONTIUM CONTENT IN SANDY SOILS IN AGRICULTURE FIELDS (CASE STUDY: MOUNDOU, CHAD)

During evaluation of physical and chemical properties of sandy soils and theirfertility in Southern part of Republic of Chad it has been revealed that some soilshave very high content of strontium. Its content varies from 10 to 270 mg/kg ofsoil depending on type of soil, depth of soil layers, clay and organic content.Strontium content negatively correlates with total content of calcium andphosphorus in layers of soil. Low CEC (CEC - Cation-exchange capacity) of soilmay be a reason of possible translocation of strontium from higher to lower layersof soils. Strontium content in soils do not relates with level of radioactivity of soilmeasured. The highest content of strontium has been found in soils developed onsome eolian and colluvio-alluvium deposits. Some researchers hypothesize thatsome endemic and chronic diseases such as Kashin-Beck disease, `Dysostosisenchondralis endemic`, endemic hoiter, osteoarthritis might be caused by highcontent of strontium in water and plant foods contaminated with it. Absence ofconsensus on etiological factors of these diseases confirms that it is worthconsidering necessity of further studies of different affects of high content ofstrontium in water and foods on human health directly or indirectly throughcausing misbalance in mineral nutrition.

Potentials and limitations for the identification of outdoor dung plasters in humid tropical environment: a geo-ethnoarchaeological case study from South India

Dung has been an important material used by humans since at least the early Neolithic Period. It accumulated within domesticated animal enclosures and it was used as fuel and fertiliser as well as construction material. While the formers were studied in details, to date, the use of dung as a construction material received less attention. Here, we present a geo-ethnoarchaeological pilot study aimed at understanding the archaeological formation processes of outdoor dung-plastered floors and the possibility to identify dung markers. We studied two house terrace in a rural village from a humid tropical environment in South India (Western Ghats). Sediment samples were collected from the plastered terrace surfaces, the terraces embankment and from forest soil controls. Multi-proxy analysis of the samples included infrared spectroscopy, phytolith and dung spherulite quantification, loss on ignition, elemental analysis and micromorphological analysis. The plastering of the floors was made by mixing a quantity of dung with water and by spreading the slurry unevenly across the terrace. This result in formation of a 0.1- to 0.5-mm-thick dung crust that the analyses showed to be rich in humified organics but with very low concentrations of phytoliths and dung spherulites. The careless spreading of the dung slurry, however, resulted in localised deposition of dung lumps that displayed relatively high concentrations of phytoliths, dung spherulites, organic matter, phosphorus and strontium. The generally low preservation of dung markers seems to be related to pre- and post-depositional processes. Forest arboreal plants are low phytoliths producer, having therefore little input of these siliceous bodies in the animal faeces. Post depositional processes included trampling, sweeping and water runoff that caused severe mechanical weathering, resulting in the heavy decay of the dung crust and the removal of dung residues from the terrace surfaces. In addition, the acidic conditions of a humid tropical environment likely promoted the complete dissolution of dung spherulites. This study provides new data and insights on the potentials and limitations of dung identification in outdoor settings in humid tropical environments. We suggest possible directions for advancing the study of archaeological dung used as construction materials.

Macroporous alginate foams crosslinked with strontium for bone tissue engineering

Nowadays, the need of novel strategies to repair and regenerate bone defects in the field of biomedical applications has increased. Novel approaches include the design of natural bioactive scaffolds mimicking bone tissue. These bioactive scaffolds have to possess biophysical properties suitable to address biological response towards newly bone tissue formation. In particular, scaffold porosity and pore size play a pivotal role in cell migration, adhesion and proliferation, thus increasing cell-material surface interaction and osteogenic signals transmission. Here we propose the development of macroporous alginate foams (MAFs) with porous and well interconnected structure, useful to enhance growth and osteogenic differentiation of human Mesenchymal Stem Cells (hMSCs). Moreover, in this study we report a new method for MAFs fabrication based on the combination of internal gelation technique with gas foaming. Strontium was employed in combination with calcium as cross-linking agent for the alginate chains and as enhancer of the osteogenic differentiation. The influence of strontium ions on the gelation kinetics, physical properties and degradation in physiological medium of MAFs was investigated. Our results suggest that the combination of internal gelation technique with gas foaming followed by freeze-drying is an easy and straightforward procedure to prepare alginate foams with high porosity and interconnectivity, able to support cell infiltration. Finally, biological assays showed how scaffolds with high strontium content are able to support cell growth and differentiation in long times by promoting osteogenic marker expression.

Crystal Structure of Cl-Deficient Analogue of Taseqite from Odikhincha Massif

An eudialyte group mineral, found in pegmatites of the Odikhincha massif (the northern part of the Siberian platform), has been investigated using X-ray diffraction, IR spectroscopy, and Raman spectroscopy. The mineral is characterized by a high strontium content and a low chlorine content. It has a trigonal unit cell with the following parameters: a = 14.2700(6) A and c = 30.057(1) A; V = 5300.6(1) A3; sp. gr. R3m. The structure has been refined to R = 0.047 in the anisotropic approximation of atomic displacements using 1697F > 4σ(F). The idealized formula (Z = 3) was found to be Na12Sr2Ca6Fe 3 2+ Zr3NbSi25O72(OH,O)4Cl(Н2О)0.2. The chemical composition and structure of this mineral are close to those of taseqite; however, it differs from the holotype sample by a low chlorine content and peculiarities of cation distribution over basic structure sites. A comparative analysis of strontium-rich eudialytes has revealed their important crystallochemical feature: selective concentration of strontium in the N4 site. Thus, taseqite, along with heterophyllosilicates, may play a role of strontium concentrator in agpaitic pegmatites.

Influence of differential diagenesis on primary depositional signals in limestone-marl alternations: An example from Middle Permian marine successions, South China

The diagenetic alteration of rhythmic successions remains one of the main challenges in paleoclimatology and cyclostratigraphy. To address this very important problem, thin sections and geochemical data of the limestone-marl alternations from Middle Permian carbonate successions in South China are examined to identify differential diagenetic effects in the petrography, organic and inorganic compositions, strontium concentrations and stable isotopic compositions of limestone beds and marl interlayers. In the Lengshuixi outcrop and the JY66-1 drill core, the most conspicuous features are that the limestone beds exhibit dense cementation, high strontium concentrations, negative oxygen isotopic values and positive carbon isotopic values. In contrast, the marl interlayers contain talc and exhibit strongly deformed and oriented bioclasts, low strontium concentrations, positive oxygen isotopic values and negative carbon isotopic values.Although differential diagenesis has occurred, some paleoclimate proxies (e.g., computed gamma-ray values) still preserve their primary signals and thus are suitable for cyclostratigraphic research. Eccentricity rhythm and millennial-scale rhythm are obviously recorded in Middle Permian limestone-marl alternations in South China. The variations in the oxygen and carbon isotopic values of limestone-marl alternations from different basins represent responses to different processes of differential diagenesis. This knowledge assumes that differential diagenesis occurs in diagenetically closed systems under the deep sea-floor. However, this assumption may not be valid in diagenetically open systems, where exotic fluids may add unexpected disturbances. Hence, it is crucial to understand diagenetic systems by determining the variations in strontium concentrations, which are as important as variations in carbon and oxygen isotopic values.

WATER-SAVING IRRIGATION REGIMES FOR VEGETABLE CROP PRODUCTION UNDER CONDITIONS OF VOLGA-DON INTERFLUVE

Soils of the southern region of Chad are developed on wind-drawn sand and colluvio-alluvium deposits of two main rivers Logone and Chari. This region of Chad is principal agricultural zone of Chad. Evaluation of physical and chemical properties of sandy soils and their fertility in this region revealed that some soils have very high content of strontium. With aim to locate areas with high content of srontium in soil, and to study its dependence on physical properties of soil and translocation of strontium in soil profile nine pedons were dug on different fields intensively used for agricultural production. Using X-ray spectrometric analysis and radiometric measuring of soil samples it has been revealed that Sr content in soil samples varies from 10 to 270 mg/kg of soil depending on type of soil, depth of soil layers, clay and organic content. Strontium content negatively correlates with total content of calcium and phosphorus in layers of soil. Low CEC of soil may be a reason of translocation of strontium from higher to lower layers of soils. Strontium content in soils do not relates with level of radioactivity of soils under study. The highest content of strontium has been found in soils developed on colluvio-alluviumdeposits. Very wide Ca/St ratioin soil samples of alluvial hydromorphic soils may cause increase of Sr content in vegetable food and drinking water. This may be one of etiological factors which directly or indirectly may cause misbalance in mineral nutrition and severe diseases of a man. It worth of considering necessity of further studies of Sr dynamic in soils under different crop production systems and how to mitigate negative effect of natural pollution of soils with this element.

Geoquímica de lantánidos de los yacimientos de fluorita de los distritos mineros de Taxco y Zacualpan, sur de México: implicaciones sobre el origen y la evolución de los fluidos

We present and evaluate lanthanide contents measured by inductively coupled plasma mass spectrometry (ICP-MS) in fluorite samples from the fluorite deposits in Zacualpan and Taxco mining districts in the south of Mexico. The information is used to distinguish different generations of fluorite, to establish a correlation between mineralization episodes and the wall rock nature, and to identify postdepositional processes.The total lanthanide content of the fluorites are variable, and early- stage fluorite samples are usually enriched in LREE. The concentration of REE in fluorite is low in comparison with the volcanic and metamorphic rocks (∑REE > 100 ppm) and is generally high respect the carbonates (∑REE < 30 ppm). There is host rock influence. The higher REE concentra- tions are in fluorites hosted by volcanic rocks. The fluorite that replaced carbonate is characterized by low REE to very low concentrations. Fluorite samples associated with sulfurs are typically enriched in HREE. Nearly all fluorites show a negative Eu anomaly similar to the REE anomaly observed in the volcanic rock. Only some early stage dark, uranium rich fluorites, from la Azul deposit, have a strong positive Eu anomaly. Direct correlation between color and REE patterns is observed in some samples.In the Zacualpan mining district, only an episode of mineralization has been discriminated, where fluorite presents flat to HREE- enriched chondrite-normalized REE patterns.In the Taxco mining district and particularly in the “Mina la Azul”, multiple hydrothermal events of mineralization have been determined. The first generation of fluorite is formed by replacement of carbonates and is characterized by very low contents of lanthanides, chondrite- normalized REE patterns similar to the limestone, high strontium content and primary textures (e.g. massive fluorite and rhythmites). The second generation of fluorite is related to the entry of new fluid to the system and has higher REE concentrations, chondrite-normalized REE patterns similar to volcanic rocks, low strontium content and secondary textures (i.e. breccias, nodules). Most of the samples show a genetic relationship between fluorite and fluids of magmatic origin.

Innovative application of portable X-ray fluorescence (XRF) to identify Göktepe white marble artifacts

An efficient and non-destructive method to classify white marble artifacts by using a hand-held, portable XRF analyzer (pXRF) is here reported. The identification is based on the uniquely high strontium content of this marble and has been verified by testing 32 artifacts, most of which had already been provenanced, using conventional micro-destructive analyses. Besides strontium, other potential provenance indicators, such as manganese and iron, were analyzed and their concentration values obtained after empirical calibration of the instrument by using 17 quarry samples of known composition. The results show that Goktepe/non-Goktepe discrimination is almost always possible (30 artifacts) and that additional analyses are required only when the Sr value is at the lower edge of the Goktepe field (2 artifacts). The success of the method, however, resides in the particular composition relative to trace elements of Goktepe and is not easily extended to other marble varieties. Main reasons are related to insufficient accuracy at low concentration values, intrinsic trace variability of marble artifacts, surface effects that may produce not representative results. Interest in the method therefore is tightly linked to the exceptional importance of Goktepe as a sculptural marble, in which case, detailed data, obtained with a fast and totally non-destructive method, may provide relevant information concerning chronology, workshops, and places of production of the artifacts.

Young-of-the-year Coho Salmon Oncorhynchus kisutch recruit in fresh waters of remote Patagonian fjords in southern Chile (51°S)

Salmonid invasions are currently recognized as one of the main threats to the conservation of freshwater ecosystems in Patagonia. Although a number of salmonid species have been introduced to Patagonia over the last century not all species have succeeded at establishing widespread and large populations. To date, there are no reports of established self-sustaining Coho Salmon (Oncorhynchus kisutch) populations in southern Chile despite propagule pressure from aquaculture. Here, we assessed the natal origin of young-of-the-year Coho Salmon collected from estuaries and lakes associated with remote Patagonian fjords (51°S) by examining their otolith microchemical composition. Low strontium concentrations along a line transect from the otolith edge to its core in fish collected in one lake are consistent with freshwater residence until the moment of capture. Fish caught in estuaries displayed instead, relatively high strontium concentrations only at the otolith edge. This pattern suggests very recent movement from freshwater down to the estuary. Our findings are consistent with the hypothesis that the juvenile Coho Salmon collected in estuaries originated in the local freshwater system (lake) and provide the first ever evidence of recruitment and probable establishment of self-sustaining Coho Salmon population in Patagonia.

Large structural modulations in the relaxor ferroelectric and intermediate state of strontium rich members (x>0.6) of the SrxBa1−xNb2O6 (sbn) solid solution series

The amplitudes of the positional, occupational and adp modulations of sbn mixed crystals are strongly enhanced for high strontium contents. The increase of structural modulations is accompanied by reduced spontaneous electric polarization largely due to smaller off-center shifts of the niobium atoms. Beyond the room temperature ferroelectric – intermediate transition near x=0.77, anomal large U33 atomic displacement parameters of the niobium atoms indicate static disorder caused by loss of orientational coupling between residual shifts of Nb atoms in neighboring NbO6 octahedra. Change of satellite intensities show a reduction from two-dimensional to one-dimensional modulation which is not consistent with tetragonal symmetry. The pseudo-tetragonally twinned crystal structure of sbn82 was refined in the orthorhombic super-space group A2mm(½0γ)000. The apparent tetragonal symmetry of the other investigated sbn samples also seems to be due to pseudo tetragonal twinning with equal twin volumes. The modulations mainly consist of cooperatively tilted NbO6 octahedra and wave-like ordered incomplete occupation of the largest cation sites (Me2a and b) by Ba2+ and Sr2+. Furthermore, the atomic displacement parameters of the Me2 sites are strongly modulated.

Formation of fine crystalline dolomites in lacustrine carbonates of the Eocene Sikou Depression, Bohai Bay Basin, East China

The genesis of the fine crystalline dolomites that exhibit good to excellent reservoir properties in the upper fourth member of the Eocene Shahejie Formation (Es 4 s ) around the Sikou Sag, Bohai Bay Basin, is uncertain. This paper investigates the formation mechanisms of this fine crystalline dolomite using XRD, SEM, thin section analysis and geochemical data. The stratigraphy of the Sikou lacustrine carbonate is dominated by the repetition of metre-scale, high-frequency deposition cycles, and the amount of dolomite within a cycle increases upward from the cycle bottom. These dolomite crystals are 2–30 μm in length, subhedral to anhedral in shape and typically replace both grains and matrix. They also occur as rim cement and have thin lamellae within ooid cortices. Textural relations indicate that the dolomite predates equant sparry calcite cement and coarse calcite cement. The Sr concentrations of dolomites range from 900 to 1200 ppm. Dolomite δ18O values (−11.3 to −8.2 ‰ PDB) are depleted relative to calcite mudstone (−8.3 to −5.4 ‰ PDB) that precipitated from lake water, while δ13C values (0.06–1.74 ‰ PDB) are within the normal range of calcite mudstone values (−2.13 to 1.99 ‰ PDB). High 87Sr/86Sr values (0.710210–0.710844) indicate that amounts of Ca2+ and Mg2+ have been derived from the chemical weathering of Palaeozoic carbonate bedrocks. The high strontium concentration indicates that hypersaline conditions were maintained during the formation of the dolomites and that the dolomites were formed by the replacement of precursor calcite or by direct precipitation.

Dielectric and ultrasonic attenuation at low temperatures on BST ceramics with high strontium concentration

ABSTRACTThis work presents experimental investigation of the low-temperature dielectric and ultrasonic responses of (Ba1−xSrx)TiO3 ceramics with high strontium concentration compositions, x > 0.825. Impedance spectroscopy measurements were performed at frequencies between 0.1 kHz and 100 kHz, and the results were correlated to those obtained with ultrasonic measurements. The anomalies observed in ultrasonic data were associated to ferroelastic and ferroelectric phase transitions. For x = 0.875 the “pinching” of ferroelectric phase transitions was observed. A brief discussion associates some peaks in the ultrasonic attenuation to anomalies in the dielectric response at temperatures below phase transition.

Geochemical Evaluation of Arimogija-Okeluse Limestones, Eastern Dahomey Basin, Southwestern Nigeria

10 representative samples of limestone were collected from the Arimogija-Okeluse Axis of the Dahomey Basin and subjected to X-Ray Fluorescence analysis. Major and Trace elements were used to classify and predict the depositional environment of Arimogija-Okeluse limestone.The results for the major oxide composition revealed that CaO content ranges from 47.6-52.31% with a mean value of 50.06%. SiO2 concentration varies from 1.94-5.24% with an average of 3.36%. Fe2O3. MgO, and Al2O3 contents have mean values of 1.702%, 1.52%, and 1.09% respectively. Other oxides; Na2O, P2O5, K2O and TiO2 are low in concentration. The Loss on Ignition also varies from 38.9-41.8 with a mean value of 40.43% suggesting a high carbonate content for the limestone. Standard Ca/Mg and Mg/Ca ratios varies from 25.87-37.63 and 0.03-0.04 with a mean of 33.31and 0.031 respectively. The high strontium content reveals a high saline environmental condition of formation for the limestone.The results obtained, however showed that the Arimogija-Okeluse limestone is a Magnesian limestone type deposited in a shallow marine environment and suitable for cement production.

Geochemical Evaluation of Arimogija-Okeluse Limestones, Eastern Dahomey Basin, Southwestern Nigeria

10 representative samples of limestone were collected from the Arimogija-Okeluse Axis of the Dahomey Basin and subjected to X-Ray Fluorescence analysis. Major and Trace elements were used to classify and predict the depositional environment of Arimogija-Okeluse limestone.The results for the major oxide composition revealed that CaO content ranges from 47.6-52.31% with a mean value of 50.06%. SiO2concentration varies from 1.94-5.24% with an average of 3.36%. Fe2O3. MgO, and Al2O3contents have mean values of 1.702%, 1.52%, and 1.09% respectively. Other oxides; Na2O, P2O5, K2O and TiO2are low in concentration. The Loss on Ignition also varies from 38.9-41.8 with a mean value of 40.43% suggesting a high carbonate content for the limestone. Standard Ca/Mg and Mg/Ca ratios varies from 25.87-37.63 and 0.03-0.04 with a mean of 33.31and 0.031 respectively. The high strontium content reveals a high saline environmental condition of formation for the limestone.The results obtained, however showed that the Arimogija-Okeluse limestone is a Magnesian limestone type deposited in a shallow marine environment and suitable for cement production.