Uranium Thorium Research Articles

Comparative analysis on small modular reactor (SMR) with uranium and thorium fuel cycle

The utilization of Small Modular Reactors (SMRs) and micro-reactors holds significant potential advantages. The primary benefits include their smaller size, accessibility to remote regions, and reduced land requirements. One noteworthy SMR is the NuScale Power Module (NPM), which has a thermal capacity of 160 MWt and operates on a 2-year cycle. However, there is a growing interest in exploring alternative fuels to enhance SMR performance and safety, and thorium has emerged as an appealing option due to its superior neutron characteristics and potential for higher fuel efficiency. This research aims to do preliminary research into adapting fuel for a thorium fuel cycle in the integral PWR (iPWR). The thorium cycle excels with an initial neutron multiplication factor of 1.134, almost the same as uranium (1.129). Additionally, the thorium cycle boasts superior neutron flux and Conversion Ratio (CR) in the thermal neutron energy range, enhancing sustainability with an average CR of 0.765, compared to 0.574 and 0.692 for uranium and uranium–thorium cycle. The addition of thorium improves efficiency in converting fertile material into fissile material with an enough criticality, where fuels incorporating thorium have a higher CR (Conversion Ratio). Furthermore, thorium fuel cycle has significantly lower production of plutonium isotopes compared to other fuel cycles. However, it faces a challenge with a high power peaking factor (PPF) of 1.923 at the Beginning of Cycle (BOC), requiring further research for mitigation.

Geophysical Constraints to the Geological Evolution and Genesis of Rare Earth Element–Thorium–Uranium Mineralization in Pegmatites at Alces Lake, SK, Canada

This investigation establishes an integrated method for rare earth elements (REE) exploration through a very promising and advanced exploration prospect in the Alces Lake area (SK, Canada) by assessing the integrated analysis of several multisource geophysical datasets. The resulting outcome provides important lithostructural information to the well-exposed, mineralized middle-to-lower crust at Alces Lake, comprising deep-seated poly-phase folds, ductile shear zones, and brittle faults. Geophysical–geological models of the Alces Lake property were constructed at different scales. The area of interest is located within the Beaverlodge Domain, about 28 km north of the Athabasca Basin’s northern margin. It contains some of the highest-grade rare earth elements (REE) in the world with the REE hosted predominantly in monazites within quartzo-feldspathic granitic to biotite–garnet–monazite–zircon-rich restite-bearing/cumulate mush melt pegmatites of anatectic origin (abyssal). Geophysical magnetic, gravity, and radiometric data were used together with Shuttle Radar Topography Mission (SRTM) images to facilitate the processing, modeling, and interpretation. Consequently, major structures were identified at different scales; however, the emphasis was given to studying those at the district/camp scale. The REE zones discovered to date occur within a large district-scale refolded synformal anticline. The eastern limb of this folded structure comprises a 30–40 km long, NW-trending shear zone/fault corridor with deep-seated structural crustal roots that may have served as the major pathway for ascending fluids/melts and facilitated the emplacement of mineralization. Thus, shear zones, faults, and folds in combination with lithological contacts/rheological contrasts appear to control residual/cumulate pegmatite emplacement and monazite deposition. Anomalies obtained from the airborne equivalent thorium survey data prove to be the most useful for REE pegmatite exploration. The results herein provide new interpretation and modeling perspectives leading to a better understanding of the distribution and lithostructural controls of REE on the property, and to new guidelines for future exploration programs at Alces Lake and elsewhere in northern Saskatchewan.

Process mineralogical study of U/Th occurrence states and the carrier minerals in refractory tantalum slag

Large quantities of work have been done previously on mineralogical properties and elements extraction of tantalum ores. However, the occurrence states and carrier minerals of U/Th in refractory slag still have not been studied in detail. The objective of this study was to investigate the tantalum slag, in order to determine the distribution and occurrences of uranium–thorium and their carrier minerals. Various techniques were used to detect the slag for chemical compositions, surface morphology and mineral dissociation. The result indicated that the U content was 1.09 × 103 mg/kg and Th was 4.62 × 103 mg/kg, thus the slag had great recovery prospect. Based on diversified characterizations, U was distributed in rare earth minerals as quantities of insoluble tetravalent forms (e.g., UF4, UO2) and a small amount of hexavalent (e.g., UF6, UO3, UO2F2), similarly Th was present in tetravalent state (e.g., ThF4, ThO2). According to AMICS (Automatic Mineral Characterization System) statistical calculation, the carrier minerals of U/Th were fluocerite, monazite and xenotime. The occurrences of U/Th were mainly in adsorption and isomorphism states in carriers, without monomers. There were high proportion of siderite and pyrolusite in slag, and radionuclides had closely relation to rare earth elements and metals. The carrier minerals were predominantly independent grains, some of which were intergrown to Fe-Mn minerals, the rare earth minerals were also associated and symbiotic with each other. By characterizing the U/Th distribution and the properties of carrier ores, this paper provided a theoretical basis for the process of recovering radionuclides from tantalum slag.

Multi-method characterization of the recent sediment from the Dibi subsidence lake in the tropical Adamawa region (central Cameroon): Implications for the palaeoenvironmental reconstruction

The evolution and functioning of various tropical ecosystems is poorly understood due to a lack of quantitative techniques to characterize the physicochemical composition of soils and sediment. Here, a detailed multi-method study of lithological changes is provided from a core taken from the silted-up Dibi subsidence lake (central Cameroon). To unravel the provenance of sediment, mineral constituents, and organic matter sources, an array of tools are applied including a spectrophotometer, a laser particle sizer, Rock-Eval pyrolysis, X-ray diffractometer (XRD), a portable X-ray fluorescence (XRF) spectrometry, and an inductively coupled plasma-atomic emission spectroscopy (ICP-AES) instruments. The studied core consists of light-colored deposits at the base (Unit 1) overlain by dark humic deposits (Unit 2). The sediment is very well graded (grading index Sd < 0.35Ф), indicative of bottom suspended to rolling transport. Unit 1 is characterized by relatively low values of total organic carbon (TOC: 2%–5%) whereas the dark Unit 2 has high contents of TOC (10%–33%). The core shows a high oxygen index (OI) value (average = 207 mg carbon dioxide (CO2)/g TOC) and a low hydrogen index (HI) value (average = 107 mg hydrocarbon (HC)/g TOC). This indicates highly altered organic matter (OM), likely from decomposed terrestrial plants. The chlorophyll-α fingerprint (peak around 675 nm) also reveals an autochtonous primary production of organic matter. The mineralogical assemblage of Unit 2 comprises kaolinite, quartz, feldspars, montmorillonite, ilmenite, siderite, gibbsite, rutile, and anatase whereas that of Unit 1 is similar but differs with the presence of illite and the absence of gibbsite. The high titanium dioxide (TiO2) and zirconium (Zr) contents confirm that the source rocks also are comprised of granites, and gneiss without volcanic rocks, such as basalts and trachytes. The source rocks have been intensively weathered using some parameters such as ln(Al2O3/Na2O), K2O/Rb, K/Al, and weathering indices, where Al2O3 denotes aluminum oxide, Na2O denotes sodium oxide, K2O denotes potassium oxide, Rb denotes rubidium, K denotes potassium, and Al denotes aluminum. The enrichment factors (EF) of redox-sensitive trace elements and their relation with TOC, the negative values of manganese/iron ratio (Mn∗) associated to three elemental ratios (cupper/zinc (Cu/Zn), thorium/uranium (Th/U), and vanadium/chromium (V/Cr)) attest to the predominance of sub-oxic to anoxic bottom waters in Dibi lake during sediment deposition. The data also show low primary productivity at the base of the core, followed by an increase towards the top, linked to the intensification of weathering and facilitated by humid climatic conditions, usually increase terrestrial input and palaeoproductivity. The petrological data show a generally warm and humid palaeoclimate. This climatic variation has contributed to the large spread of the savannah and disappearance of the forest. This study sheds light on the late Pleistocene to Holocene palaeoenvironment evolution of the Adamawa region which could be integrated into the context of the Pleistocene to Present regional evolution of the tropical palaeoenvironment.

The control of particulate matter and hydrogeochemistry on uranium–thorium partition coefficients in two representative lakes, Qaidam Basin, China

Radionuclides (including those of uranium and thorium) are commonly used to quantify complex geochemical processes in aqueous environments. The estimation of mass transport fluxes for uranium (U) and thorium (Th) isotopes is plagued, however, by uncertainties predominantly driven by the inability to determine solute–particulate partition coefficients (Kd). Such uncertainties are especially pronounced for lakes in rarely studied, environmentally sensitive areas. This study examines the factors controlling the Kd values of U and Th isotopes in both freshwater (Keluke Lake) and saline water (Tuosu Lake) lakes within the Qaidam Basin, China, a basin sensitive to the impacts of climatic change. The analysis found a negative correlation of both Kd(Th) and Kd(U) with the concentration of suspended particulate matter (SPM), suggesting that particle concentrations affect Kd values in the sandy Keluke Lake. In contrast, there was no significant correlation between Kd values and SPM in the muddy (fine-grained) Tuosu Lake. Compositionally, three types of particles were found in both lakes and were derived from the same sediment sources. The Kd values were primarily controlled by lake evaporation and/or secondary water–rock interactions that were influenced by hydrogeochemical ecosystem differences between the lakes. In addition to differences in particle composition and concentrations, redox potential, ionic strength, organic matter concentration and pH of the lake water were likely to influence the Kd(Th) and Kd(U) values. These results are not only of significance to quantitative studies of U and Th isotopes in water (e.g., reducing transport flux uncertainties and improving the precision of U–Th isotope dating), but also provide an important reference for the application of radionuclides in other climate sensitive regions of the world.

Methane Seepage Caused by Gas Hydrate Dissociation in the Mid‐Okinawa Trough Since the Last Glacial Maximum

AbstractSubmarine methane seepage can potentially be promoted by the dissociation of the marine hydrates surrounding the continental margins due to oceanic warming since the Last Glacial Maximum. This seepage could be archived by authigenic carbonates at seeping sites, but the time lag caused by heat transmission through the sediment column leads to an inconsistency between the ages of the carbonate and the period of bottom water warming. Here we present the records of the authigenic carbonate crust from drilling site D1 in the Mid‐Okinawa Trough. Uranium–thorium dating results show that the carbonate crust mainly grew downwards during 14–6 ka. Gas hydrates hosted in the relatively thin stability zone dissociated in a rapid response to bottom water warming and intensified the methane seepage. Our study better supports the hypothesis that a considerable amount of methane can be released from marine hydrates due to global climatic changes.

Selectivity and affinity of heavy metals and radiometals for organic biomass: Implications for water remediation

ABSTRACT Due to both natural and anthropogenic causes, waterways have a history of contamination with different heavy metals and radiometals. Among these, thorium (Th,) uranium (U,) arsenic (As,) and strontium (Sr) are noteworthy threats to humans due to chemical and radiological toxicity. Previous research has focused on inorganic materials to remove these metals. However, the use of recyclable and biodegradable waste materials to remove toxic metals has risen. This study seeks to use pistachio shells as a model for heavy metal selectivity and affinity for organic biomasses. The influence of kinetics and pH on selectivity/affinity of the shell for the metals was investigated. The individual metal affinity seen was Th > U > As > Sr. Selectivity for Th and U over As and Sr was seen at pH < 6, beginning to equalize at pH > 6. The maximum uptake for all metals tested occurs at pH 5 and t ≥2 h. Uptake of these metals follows pseudo-second order, intraparticle kinetics, and Freundlich isotherm. Finally, the selectivity of the shells for heavy metals was investigated using drinking water and seawater samples, with concurrent pronounced uptake of actinides and Sr being observed.

Geochemistry and Petrogenesis of the Ediacaran Post-Collisional Granitoid Rocks in the Midyan Terrain, Northern Arabian Shield, Saudi Arabia

Midyan granites are located in the northern Arabian shield, northwest Saudi Arabia, in the Midyan terrain. They represent the most northerly segment of the Arabian–Nubian shield, which comprises the northern part of the East African orogeny. Consequently, understanding the origin of post-collisional and anorogenic magmatism in the Midyan terrain has significant geodynamic implications. Midyan granites are mainly composed of alkali feldspar granite, syenogranite, and rarely of granodiorite and diorite. Most of the studied granites are alkali-calcic, calc-alkaline, and metaluminous to peraluminous magma types. They are characterized by enrichment with light rare earth elements (LREEs), large-ion lithophile elements (especially Rb and Th), and some high-field strength elements (HFSE, e.g., Nb, Ta, Zr, and U), and the slight depletion of heavy rare earth elements (HREEs). Therefore, the Midyan granites and Hael granites studied in this paper represent good sources of geothermal heat, uranium–thorium, and REE mineralization. The studied granites have moderately strong negative Eu anomalies and a distribution pattern that is very consistent with that of the upper crust, indicating the presence of plagioclase or potassium feldspar cumulates. They have a Th/Ta ratio similar to that of the source of the crust, which may be derived from the upper crust following the collision between East and West Gondwana in the final stage of the Arabian Shield evolution. The data presented in this study are therefore consistent with the post-collisional intraplate magmatism that occurred at the beginning of the transition from convergent to extensional tectonics. The studied granites are derived from melt generated at a crystallization temperature of around 750°C at a pressure of around 0.2–0.5 GPa, emplaced at relatively shallow to moderate depths of between 20 and 30 km.

Light Water Reactors with Thorium–Uranium Heterogeneous Fuel in a Nuclear Energy System

Light Water Reactors with Thorium–Uranium Heterogeneous Fuel in a Nuclear Energy System

U-Th dating, taphonomy, and taxonomy of shell middens at Klasies River main site indicate stable and systematic coastal exploitation by MIS 5c-d

The archaeological record, particularly of shellfish, from the Klasies River main site (KRM) is important in understanding the fluctuating nature of coastal occupational patterns and changing coastal ecologies. In this paper, we provide new uranium–thorium (U-Th) dates for one of the earlier phases of coastal exploitation at KRM, and the microstratigraphic analyses generate novel information about the taphonomy of shell-bearing deposits from the Later Stone Age (LSA) to the MSA I period that, in turn, provide a broader context for middening at the site. A wide range of syndepositional taphonomic processes related to human activities and post-depositional effects include burning, fragmentation and compaction, chemical alteration, and cementation. Despite such issues influencing recovery, shellfish data are informative and are presented from three layers of the Witness Baulk: Shell Midden One (SMONE), Black Occupational Soils (BOS), and Silty Black Soils (SBLS). These coarse shell midden deposits exhibit visible decalcification coupled with cementation with secondary carbonate formation in association with conditions of high moisture and soft sedimentation deformation of the underlying sediments of SBLS. This stratigraphy section is chronologically anchored for the first time using U-Th dating of speleothems associated with a hiatus after the deposition of BOS. The three ages, 110,060 ± 1,100, 109,800 ± 970, and 106,000 ± 2,100 years, place the BOS layer as the base of the SASL sub-member at over 110 ka, making the underlying middens from the LBS member even older. The zooarchaeological analyses of the three layers indicate coastal ecological changes from more sheltered conditions prior to the hiatus, with the exploitation of alikreukel and brown mussels predominating. Before 110 ka, in BOS and SBLS, more exposed coastal conditions occurred, and the diversity of exploited shellfish increased. SMONE and BOS are associated with MSA II/Mossel Bay lower lithic technology and SBLS with MSA I technology, indicating asynchronous coastal ecological and technological changes. The MIS 5c-d evidence for early coastal occupation at KRM provides details on the period during which coastal occupation became stable and systematic on the South African coast and puts the KRM amongst the handful of sites with shell-bearing deposits, occurring prior to 110 ka in South Africa.

Rare Earth–Uranium–Thorium Mineralization in the Molybdenum Ores of the Buluktaevskoe Mo–W Deposit (Western Transbaikalia, Russia)

—The Buluktaevskoe molybdenum–tungsten deposit is considered a close analog of W–Mo deposits within the large Dzhida orefield, in which the Pervomaiskoe molybdenum and Inkurskoe and Kholtosonskoe tungsten deposits are known. Fifteen ore minerals were identified in the molybdenum ores of the Buluktaevskoe deposit; in addition to molybdenite, they include sulfides (pyrite, galena, and chalcopyrite), tungstates (wolframite and scheelite), molybdates (powellite and wulfenite), and a relatively large number of minerals containing rare earth elements (REE), U, and Th (Th-bearing monazite, brannerite, thorite, and uraninite); among them are previously unknown minerals: fluorine-bearing thorium molybdate and minerals with compositions corresponding to rare mineral species, orthobrannerite and kobeite-(Y). Interrelations and specific chemical compositions of the uranium–thorium–rare earth element minerals are discussed. It was established that these minerals formed in the course of hydrothermal alteration processes, at the early (molybdenite) development stage of the Buluktaevskoe molybdenum–tungsten deposit.

Oxidation behaviour of thorium-uranium mixed oxides in controlled oxidation experiments

Oxidation experiments in Ar/H2O/H2 gas mixtures were performed using a coulometric titration technique to investigate the oxidation behaviour of single-phase thorium–uranium mixed oxides under a controlled oxygen potential relevant to defective fuel operating conditions. The oxidation behaviour of the mixed-oxide (Th,U)O2 solid solutions with 8, 30, 60 and 100 wt% UO2 was investigated through oxygen-to-metal (O/M) ratio measurements combined with X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge spectroscopy (XANES), extended X-ray absorption fine structure (EXAFS) analysis, and neutron diffraction analysis (NDA). The local structure around U examined by EXAFS did not show any evidence of local clustering. The U L3 EXAFS results of (Th,U)O2 show that the local structures do not appear to depend on the UO2 content. This is an indication that Th and U are randomly distributed in the mixed oxides, which is in good agreement with the long-range structural properties determined by XRD and NDA. The XPS results combined with XANES results of the U L3 edge confirmed the oxidation of U4+ for all compositions. An examination of the U L3 EXAFS spectra from the oxidized samples shows a split in the first coordination shell peak, which indicates the presence of different U–O bond-lengths in the oxidized materials. The long-range structure of the oxidized materials was characterized with NDA. Rietveld refinement revealed that the oxidized (Th,U)O2 materials with high UO2 content were biphasic. The quantitative phase analysis demonstrated the co-existence of two closely cubic structures: a stoichiometric (Th,U)O2 phase and a UO2.06 phase. These observations suggest that the oxidation of uranium in the (Th,U)O2 mixed oxides occurred in the bulk of the samples as well as at the surface as revealed by XPS analysis.

Assessment of radiological health risk and radiogenic heat production changeability of different sedimentary rocks at Gabal Um Hamd, Southwestern Sinai, Egypt

Soil is a source of natural radionuclides and a source of natural radiation risk to humans. This study aims to measure the radioactivity concentrations, contributions, radiological hazards and to quantify the radiogenic heat productions in thirty two rock samples having different lithology from the middle member of Um Bogma Formation in Gabal Um Hamd, southwestern Sinai, Egypt. The concentration of natural radionuclides was determined using a p-type Hyper Pure Germanium (HPGe) detector. The average activity concentrations of uranium thorium and potassium in the interested area were found to be 4909.58 ± 54.34 5003.12 ± 17.56 79.04 ± 8.82 and 137.35 ± 8.64 respectively. Other hazard indices average values were measured, such as: annual effective dose equivalent, radium equivalent activity, external and internal indices, annual gonad equivalent dose, and excess lifetime cancer risk. The radiologic hazards results, obtained in this study shows that the radiation levels are higher than the internationally approved values and the recommended safety limits. Furthermore, the results show that the radiogenic heat value ranged from 3.58 to 402.45 μW m −3 with an average value of 60.11 ± 0.79μW m −3 in the studied area which is higher than previously reported averages.

Comparison of thorium nitride and uranium nitride fuel on small modular pressurized water reactor in neutronic analysis using SRAC code

Comparison of thorium nitride (ThN) and uranium nitride (UN) fuel on small modular PWR in neutronic analysis has been carried out. PWR in module is one type of reactor that can be utilized because of its small size so that it can be placed on demand. Neutronic calculations were performed using SRAC version 2006, the data library using JENDL 4.0. The first calculation was fuel pin (PIJ) calculation with hexagonal fuel pin cell type. And the second calculation was reactor core (CITATION) calculation using homogeneous and heterogeneous core configurations. ThN and UN fuels use heterogeneous configurations with 3 fuel variations. The reactor geometry was used in two fuels are the same, with diameter and height active core was 300 cm and 100 cm. In this research, Np-237 was added as a minor actinide in the UN fuel to reduce the amount of Np-237 in the world and also reduce the k-eff value. For ThN fuel, Pa-231 also added in the fuel to reduce the k-eff value. The optimum configuration of UN fuel reached when used heterogeneous core configuration case four with percentage of U-235 in F1=5.5 %, F2=7 % and F3=8.5 % also with the addition of Np-237 0.2 % and fuel fraction 56 %. It has a maximum excess reactivity value 12.56 % %∆k/k. And then, the optimum configuration of ThN fuel reached when used heterogeneous core configuration case three with percentage of U-233 in F1=2 %, F2=4 % and F3=6 % with the addition of Pa-231 0.5 % and fuel fraction 53 %. It has a maximum excess reactivity value 7.67 % %∆k/k. The comparison of optimum design of UN and ThN fuel shows that the ThN fuel has the k-eff value closer to critical than UN fuel. Therefore, in this study, ThN fuel is more suitable for use in PWR reactors because it has a small excess value and can operate for 10 years without refueling

Last interglacial sea-level proxies in the glaciated Northern Hemisphere

Abstract. Because global sea level during the last interglacial (LIG; 130–115 ka) was higher than today, the LIG is a useful approximate analogue for improving predictions of future sea-level rise. Here, we synthesize sea-level proxies for the LIG in the glaciated Northern Hemisphere for inclusion in the World Atlas of Last Interglacial Shorelines (WALIS) database. We describe 82 sites from Russia, northern Europe, Greenland and North America from a variety of settings, including boreholes, riverbank exposures and along coastal cliffs. Marine sediments at these sites were constrained to the LIG using a variety of radiometric methods (radiocarbon, uranium–thorium, potassium–argon), non-radiometric methods (amino acid dating, luminescence methods, electron spin resonance, tephrochronology) as well as various stratigraphic and palaeo-environmental approaches. In general, the sites reported in this paper do not offer constraint on the global LIG highstand, but rather evidence of glacial isostatic adjustment (GIA)-influenced sea-level positions following the Marine Isotope Stage 6 glaciation (MIS 6; 191–130 ka). Most of the proxies suggest that sea level was much higher during the LIG than at the present time. Moreover, many of the sites show evidence of regression due to sea-level fall (owing to glacial isostatic uplift), and some also show fluctuations that may reflect regrowth of continental ice or increased influence of the global sea-level signal. In addition to documenting LIG sea-level sites in a large swath of the Northern Hemisphere, this compilation is highly relevant for reconstructing the size of MIS 6 ice sheets through GIA modelling. The database is available at https://doi.org/10.5281/zenodo.5602212 (Dalton et al., 2021).

UThwigl — An R package for closed- and open-system uranium–thorium dating

For several decades, uranium–thorium (U–Th) dating has allowed geochronologists to precisely date geological materials, providing invaluable geochronological constraints on Quaternary processes. Open-system dating of bones and teeth has also provided ages of human and faunal remains of archaeological significance. To facilitate access to closed- and open-system U–Th dating to the broad scientific community, here we provide an R package, named UThwigl . Description of input and output parameters is given, as well as a guide for running the model. The package can be used three different ways: (i) as a web application, (ii) through a web browser with an internet connection, or (iii) in R (most efficiently with RStudio). Examples of application of the model are also provided, showing that it yields ages within error of previously published values.

U-Th isotope data for dust sampled along a west to east transect in eastern Australia and some bedrock from the Flinders Ranges

In this communication we present Uranium-Thorium (U-Th) isotope data for surficial dusts sampled along a west to east transect in eastern Australia and some selected bedrock samples from the Flinders Ranges near the western end of the transect. The dusts have lost 238U and 234U within the last 350 kyr implying a combination of chemical (bulk U loss) and physical (recoil loss of 234U) weathering. Near-surface bedrock is not always in U-Th isotope secular equilibrium as commonly assumed in studies of weathering, erosion and soil production.

Estimation of radioelements concentration in Sokoto Basin for geothermal energy studies using airborne radiometric data

High resolution aero-radiometric data of Sokoto basin Northwestern, Nigeria were used in this research work. The location of the basin is between latitude 11o30I to 13o30IE and longitude 4o30I to 6o30IN. Sixteen (16) sheets of high resolution of airborne radiometric data were used to obtain the concentration of Potassium (K), Uranium (U) and Thorium (Th) respectively in the area of interest. The data were gridded and analyzed using Geosoft software. The result of the analysis revealed that potassium concentration is between -0.577935% to 7.34347% with an average of 3.3827%. The Thorium concentration values ranged from -3.81541ppm to 91.9404ppm with an average of 44.0624ppm. The Uranium concentration revealed values from -4.44524ppm to 46.1767ppm with an average of 20.86572ppm. The ratio of potassium and equivalent thorium (K/eTh) indicated values between -8.69847%/ppm to 39.567%/ppm and ratio of equivalent uranium and equivalent thorium (eU/eTh) revealed values between -412.181ppm to 99.4613ppm. The ternary diagram of the radiometric data showed that the south and southeastern regions of the study area have high radioactive mineral concentration above the average normal value of radioactive minerals in a natural environment and radioactive minerals are good source of geothermal energy. The results obtained has shown that the basin has geothermal potential which can cause non productivity of hydrocarbon in the area of interest and the research area can be recommended for geothermal energy resource to compliment the electric power supply in the nation.

A global compilation of U-series-dated fossil coral sea-level indicators for the Last Interglacial period (Marine Isotope Stage 5e)

Abstract. This dataset is a comprehensive, global compilation of published uranium–thorium (U-series) dated fossil coral records from ∼ 150 000–110 000 years ago, as well as associated elevation measurements and sample metadata. In total, 1312 U-series measurements from 994 unique coral colonies are included in the current version of the dataset, all of which have been normalized and recalculated using the same decay constant values. Of these measurements, 444 analyses from 330 colonies are relative sea-level indicators, whereas 15 analyses from 13 colonies are marine limiting. Two example geochemical screening criteria have been included to assist users with identifying altered fossil corals that display geochemical open-system behavior, and the originally published interpretations on age quality have been preserved within the sample metadata. Additionally, a clear distinction has been made between coral colonies that are in primary growth position, which may be used for relative sea-level reconstructions, and colonies that have been transported/reworked, which cannot be used for these purposes. Future research efforts involving fossil coral sea-level reconstructions should emphasize an “integrated” and holistic approach that combines careful assessment of U-series age quality with high-precision surveying techniques and detailed facies/stratigraphic observations. This database is available at https://doi.org/10.5281/zenodo.4309796 (Chutcharavan and Dutton, 2020).

Some problems of the application of the U–Th series and radiocarbon absolute dating techniques to Quaternary fluviolacustrine deposits in the Morsott commune of Algeria

Two radioisotopic dating methods are applied to Quaternary fluviolacustrine detritus deposits in the commune of Morsott in northeastern Algeria. The studied profile shows an open and contaminated environment. In the case of the shells of molluscs, the choice of identical samples for both the dating methods is wise. Obtained results are different; thus, positioning the chronology of the Quaternary sequence is difficult. The uranium–thorium (U–Th) series technique gives a younger age than that provided by radiocarbon (14C) in Holocene. For carbonates at the base of the study sequence, the age difference is 278,154 ka BP. In the lowermost level of limestone crusts in the last Pleistocene, 14C gives a younger age than that provided by the U–Th series technique, rendering the chronological order of the levels inconsistent. Despite the corrections of the U–Th series technique and the age calibrations of 14C, this method is recommended for open systems (environments). Contamination related to either post depositional parameters or sample preparation techniques is certain in this type of open environments. In open environment applications, the reliability of the U–Th series or 14C technique changes from the upper to the bottom of the studied series as the function of various external parameters. For this reason, including other techniques is necessary to confirm and understand the chronology of Quaternary.