Abstract High‑uranium apatite samples from iron oxide-apatite (IOA) deposits of the eastern Adirondack Mountains, New York, are evaluated as potential standards for in situ U-Pb dating of high-U apatite. Age data for these minerals also have implications for better understanding the geological evolution in the region. Secondary ion mass spectrometry (SIMS), and laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) analyses of these samples show that they have high and variable uranium contents of 5–485 ppm. High-precision isotope-dilution thermal ionization mass spectrometry (ID-TIMS) dating yielded U–Pb errorchron ages of 907 ± 14 Ma (MSWD = 20) and 924 ± 13 Ma (MSWD = 547), showed disturbance in the U–Pb systems, and revealed radiogenic compositions of initial Pb (206Pb/204Pb ratios of 339 ± 48 and 162 ± 39). Nominal age calculations using assumed initial Pb isotopic compositions close to average terrestrial crustal Pb yield biased and older ages despite the radiogenic Pb isotopic composition of the apatites (206Pb/204Pb from 1300 to >4000). The apatite ages calculated using the measured initial Pb isotopic compositions are younger than the U–Pb ages of 1008.0 ± 3.2 Ma and 992.4 ± 7.7 Ma determined by SIMS for zircon cores and rims, respectively, separated from one of these ore samples. It indicates protracted fluid activity in the deposit that lasted for ~100 Ma after the ore formation, or later disturbance of the apatite. The time of U enrichment that we inferred from radiogenic composition of initial Pb is within uncertainties with primary ore crystallization, indicating that high 206Pb/204Pb ratios of initial Pb were caused by dissolution-reprecipitation of primary apatite. Despite the variability in U contents and disturbance of the U–Pb system in the apatites, our SIMS and LA-ICPMS analyses show that these samples can be used, with due caution, as reference materials (RMs) for dating apatite with similarly high-U concentration. They potentially provide more precise and accurate results compared to the usage of better behaved but lower-U apatite RMs due to improved counting statistics and reduced matrix effects, especially important for LA-ICPMS with less sensitive quadrupole mass analysers. The McClure Mountain apatite, a widely used reference for in situ dating, was used in the present study as a matrix-matched reference material for in situ LA-ICPMS analyses. We also analysed it by ID-TIMS and obtained more radiogenic Pb-isotopic data and more precise ages that are in agreement within uncertainties with the previously published result ( Schoene and Bowring, 2006 ); combined data yielded a U-Pb errorchron age of 525.3 ± 1.7 Ma (MSWD = 70). The data corrected for initial Pb using the total U/Pb isochron yield the single Concordia age of 525.10 ± 0.75 Ma (MSWD = 1.1). Two independent ID-TIMS U–Pb studies support the use of this apatite as a primary RM for dating of low-U apatite with a normal composition of initial Pb. However, its small grain size and low U concentration (11–29 ppm) can cause elevated uncertainty in LA-ICPMS age determinations for unknowns. Better precision in our LA-ICPMS analyses was achieved using Madagascar (MAD1 and MAD2) apatite RM with U contents in the range of 28–58 ppm.

In the laboratories of the Zarazma Mineral Studies Company in Tehran, the Islamic Republic of Iran, measurements of Uranium content in soil samples were made utilizing ICP-MS (inductively coupled plasma mass spectrometry) in 36 samples of surface soil from selected locations (Some of which, according to the authors, were measured for the first time) in the Northern Basrah governorate. Uranium concentrations were found to range from ( 0.9 ppm ) in Al-Awjan to ( 1.5 ppm ) in Al-Ez River soils. The findings are given and contrasted with those of other research. The soil samples analyzed were uranium less than 100 ppm, which implies an amount of overburden and reserves instead of mineable reserves. The concentration of uranium in the Northern Basrah Governorates is presented and evaluated in this article. The study also indicates that uranium levels in 36 samples of surface soil are below the detection limit. The current findings demonstrate that the uranium contents in the surface soil samples examined were lower than the UNSCEAR-recommended limit of 11.7 ppm.

Investigation for uranium dispersion adjacent to cretaceous phosphatic outcrops in Al-Nassrieh Basin, southern Palmyrides, Syria | Journal of Earth Science | Springer Nature Link Skip to main content Advertisement Investigation for uranium dispersion adjacent to cretaceous phosphatic outcrops in Al-Nassrieh Basin, southern Palmyrides, Syria Published: 14 October 2016 Volume 27 , pages 786–795 ( 2016 ) Cite this article Save article View saved research Journal of Earth Science Aims and scope Submit manuscript Abstract A detailed radiometric survey including soil gas radon measurements and field gammaray survey, in accordance with geochemical and geological investigations were carried out in Al-Nassrieh Basin (central Syria), for the purpose of uranium exploration. Thirty-six samples were collected from various lithofacies of the survey area and analyzed by γ-ray spectrometric technique for determining the concentration values of major radioelements. The relationships between the concentrations of equivalent eU, eTh, and their ratios were examined in order to define their trend of variations and evaluate the degree of uranium remobilization and redistribution. Although the initial results indicate that uranium enrichment is mostly restricted to the Upper Cretaceous phosphate rocks, a considerable portion of uranium appeared to be leached out of the primary phosphatic source and dispersed in the adjacent recent sediments. Further, notable increases of radon level associated with relatively high values of uranium concentration and gamma count rates were found to be spatially correlated with the transition zone between the marine Paleogene and continental Neogene formations throughout the study basin. This observation demonstrates the importance of the concerned zone as a suitable geological environment for hosting probable uranium mineralization along a chemically reducing interface where surface water of terrestrial and marine origin mingled at depth and away from surficial conditions. This is a preview of subscription content, log in via an institution to check access. Geological and Hydrogeological Conditions for Forming Uranium Occurrences in the Froqlos-Jabal Abou Rabah Region, Palmyrides, Syria. Exploration and Mining Geology , 19(1–2): 1–12 Article Google Scholar Baubron, J. C., Rigo, A., Toutain, J. P., 2002. Soil Gas Profiles as a Tool to Characterize Active Tectonic Areas: The Jaut Pass Example (Pyrenees, France). Earth Planet. Sci. Lett. , 196: 69–81 Article Google Scholar Chiozzi, P., Pasquale, V., Verdoya, M., 2002. Naturally Occurring Radioactivity at the Alps–Apennines Transition. Radiation Measurements , 35: 147–154 Article Google Scholar Dickinson, K. A., Leventhal, J. S., 1988. The Geology, Carbonaceous Materials and Origin of the Epigenetic Uranium Deposits in Tertiary Sespe Formation in Ventura County, California . U. S. Geological Survey Bulletin, 1771. Google Scholar Dyck, W., 1975. Geochemistry Applied to Uranium Exploration. Uranium Exploration . Geological Survey of Canada, 33–47 Google Scholar Fouad, K. M., Rabie, S. I., Khalil, A. F., 1998). Recognition of the Degree of Remobilization of Uranium from Airborne Gamma-Ray Spectrometric Survey Data: Proceeding of the Fourth Arab Conference on the Peaceful Uses of Atomic Energy, Volume III (Scientific Presentations B), 14–18 /11/1998, Tunis. 45–68 Ghosh, D., Deb, A., Sengupta, R., 2009. Nuclear Tracks and Radiation Measurements , 19: 383–384 Article Google Scholar Tilsley, J. E., 1988). Genetic Concentrations Relating to Some Uranium Ore Deposits. In: Roberts, S., ed., Ore Deposit Models . Geoscience Canada. 194 Google Scholar Download references Author information Authors and Affiliations Department of Geology, the Atomic Energy Commission of Syria (AECS), Damascus, 6091, Syria Mohamed Al-Hilal & Ahmad Al-Ali Authors Mohamed Al-Hilal View author publications Search author on: PubMed   Google Scholar Ahmad Al-Ali View author publications Search author on: PubMed   Google Scholar Corresponding author Correspondence to Mohamed Al-Hilal . Copy shareable link to clipboard Provided by the Springer Nature SharedIt content-sharing initiative Keywords radiometric survey geochemistry uranium exploration Al-Nassrieh Basin Syria Access this article Log in via an institution Subscribe and save Springer+ from €37.37 /Month Starting from 10 chapters or articles per month Access and download chapters and articles from more than 300k books and 2,500 journals

The uranium content of stalagmites is the foundation of stalagmite chronology research. It directly determines whether a stalagmite sample is suitable for paleoclimate research and affects the accuracy and precision of stalagmite dating results. Currently, two uranium-series dating techniques are commonly used for stalagmites: U-Th dating and U-Pb dating. The U-Th method can date samples up to approximately 690,000 years old, while the U-Pb method extends the dating range to the Paleozoic or even earlier geological periods. However, the reliability of both methods is highly dependent on the uranium concentration in the stalagmites. Stalagmite samples with low uranium content often result in large age uncertainties, which can lead to significant misinterpretations of the timing and duration of past abrupt climatic events, thereby compromising the accuracy of paleoclimate reconstructions. Therefore, investigating the factors that influence uranium concentrations in stalagmites is of great significance both theoretically and practically. Such understanding can help identify high-uranium stalagmite samples, enhance dating precision, and ultimately support the establishment of more robust chronological frameworks. Nevertheless, current knowledge of the mechanisms controlling uranium content in stalagmites remains limited. Most existing studies focus on the climatic significance of uranium concentration and initial (234U/238U) ratios in stalagmites. Previous studies have shown that

Gamma-ray measurements of naturally occurring radioactive samples from Cyprus characteristic geological rocks Using high-resolution gamma-ray spectroscopy, the terrestrial gamma radiation in all the predominant types of geological rock formations appearing in Cyprus was measured. Soil samples were collected from each rock type, sealed in 1-litre plastic Marinelli beakers, and measured in the laboratory for 24 hours each. From the measured gamma-ray spectra, activity concentrations were determined for Th-232 (range from 1.3 to 52.8 Bq/kg), U-238 (from 0.9 to 90.3 Bq/kg) and K-40 (from 13 to 894 Bq/kg). Elemental concentrations mean values of (2.8 +- 0.7) ppm, (1.3 +- 0.3) ppm and (0.6 +- 0.1) % were extracted, for thorium, uranium and potassium, respectively. Absorbed dose rates in air outdoors were calculated to be in the range of 0.1-50 nGy/h, depending on the geological features, with an overall mean value of (14.7 +- 7.3) nGy/h. The corresponding effective dose rates per person outdoors were estimated to be between 0.1 and 61.4 microSv/y, assuming a 20% occupancy factor. Published as: Radiat.Meas. 37 (2003) 221-229 arXiv categories: physics.med-ph nucl-ex physics.soc-ph

spontaneous fission of uranium-238 impurities. The uranium content of the sample has to be known, but that can be determined by placing a plastic film Radiometric dating, radioactive dating or radioisotope dating is a technique which is used to date materials such as rocks or carbon, in which trace radioactive impurities were selectively incorporated when they were formed. The method compares the abundance of a naturally occurring radioactive isotope within the material to the abundance of its decay products, which form at a known constant rate Th… The basic equation of radiometric dating requires that neither the parent nuclide nor the daughter product can enter or leave the material after its formation. The possible confounding effects of contamination of parent and daughter isotopes have to be considered, as do the effects of any loss or gain of such isotopes since the sample was created. It is therefore essential to have as much information as possible about the material being dated and to check for possible signs of alteration. Precision is enhanced if measurements are taken on multiple samples from different locations of the rock body. Alternatively, if several different minerals can be dated from the same sample and are assumed to be formed by the same event and were in equilibrium with the reservoir when they formed, they should form an isochron. This can reduce the problem of contamination. In uranium–lead dating, the concordia diagram is used which also decreases the problem of nuclide loss. Finally, correlation between different isotopic dating methods may be required to confirm the age of a sample. For example, the age of the Amitsoq gneisses from western Greenland was determined to be 3.60 ± 0.05 Ga (billion years ago) using uranium–lead dating and 3.56 ± 0.10 Ga (billion years ago) using lead–lead dating, results that are consistent with each other. Accurate radiometric dating generally requires that the parent has a long enough half-life that it will be present in significant amounts at the time of measurement (except as described below under "Dating with short-lived extinct radionuclides"), the half-life of the parent is accurately known, and enough of the daughter product is produced to be accurately measured and distinguished from the initial amount of the daughter present in the material. The procedures used to isolate and analyze the parent and daughter nuclides must be precise and accurate. This normally involves isotope-ratio mass spectrometry. The precision of a dating method depends in part on the half-life of the radioactive isotope involved. For instance, carbon-14 has a half-life of 5,730 years. After an organism has been dead for 60,000 years, so little carbon-14 is left that…

United States heavy reliance on imports of critical minerals (CMs), including rare earth elements (REEs), underscores the importance of development of domestic sources. The study objective was to quantify CM and REE concentrations in coal and coal ash in the US Gulf Coast region. CM and REE concentrations were measured for 118 samples from outcrops and 14 mines in the Gulf Coast. Results show that total REE + Yttrium (REY) concentrations (dry coal basis) are comparable to those of the upper continental crust (UCC) with localized hot spots, such as the Texas Gibbons Creek mine (REY ≤ ~ 2860 ppm). When normalized to UCC REY concentration (169 ppm, dry coal basis), REY to UCC ratios for Gulf Coast coal samples range from 0.1 to 17 (median ratio 0.6). REE extractability from lignites is high (median: 63%–93%) using environmentally benign weak acid. In addition to raw coal, coal ash from power plants could also serve as an REE source with a median ratio of REY in ash relative to coal of 4; however, extractability from coal ash is generally much lower (≤ 5% using the same weak acid as in coal). The median basket price for extracted REY as oxides from coal, assuming 70% extractability, is $\$3.2$ per tonne of coal and $\$186$ billion based on 58 billion metric tonnes of dry coal in the Gulf Coast. REEs important for magnets (Pr + Nd + Tb + Dy) account for ~ 80% of the total value. The corresponding median basket price for extracted REY as oxides from coal ash, assuming ~ 30% extract