Thorium abundance is three times that of uranium in the Earth's crust ( Adams and Richardson, 1960; Korna et al., 2014; Asokan et al., 2020 ), it is usually mined from monazite, a phosphate mineral, …

Abstract. The uranium-thorium (U-Th) method can constrain the age of cave art by providing dates of formation of calcite deposits from on top of paintings or calcite layers on which paintings were done. It is particularly useful for art made without radiocarbon datable organic pigments or binders, or where contamination of radiocarbon samples ...

Abstract. Thorium, uranium, and potassium concentrations have been determined in nineteen sands and sandstones by γ-ray spectrometry, fluorometric uranium analysis, and α-counting. The samples were selected so that both common and extreme thorium and uranium ratios would be represented.

Abstract. A recent revision of oscillator strengths for U II and T II makes it appear almost certain that there are some Ap stars for which the U/Th ratio is an order-of-magnitude (or more) greater than the meteoritic value. ... The geoneutrinos produced by the radioactive decays of uranium and thorium have been observed with the Kamioka Liquid ...

Abstract. This paper reports the continued evaluation of the attractiveness of materials mixtures containing special nuclear materials (SNM) associated with various proposed nuclear fuel cycles. ... {osti_1017493, title = {An assessment of the attractiveness of material associated with thorium/uranium and uranium closed fuel cycles from a ...

ABSTRACT Because of analytical difficulties, few data are available on the thorium and uranium contents of sedimentary rocks. More than 200 new thorium and uranium determinations have been made by a gamma-ray spectral technique and by an alpha …

Abstract. Thorinm, uranium, and potassium concentrations have been determined in nineteen sands and sandstones by gamma -ray spectrometry, fluorometric uranium analysis, and alpha counting. The samples were selected so that both common and extreme thorium and uranium ratios would be represented.

Abstract The mechanism and chemical nature of uranium and thorium sequestration by a Pseudomonas strain was investigated by transmission electron microscopy, energy dispersive X-ray (EDX) analysis, FTIR spectroscopy and X-ray diffractometry. Atomic force microscopy (AFM) used in the tapping mode elucidated the …

Uranium and thorium are the only naturally-occurring actinides in the Periodic Table of the Elements, and share many similar properties such as: the order of magnitude of the half-lives of their most abundant isotopes (238 U and 232 Th), their primary …

Abstract. An investigation of the uranium (U), thorium (Th), and lead (Pb) isotopic systematics was made on the whole rock, microcline, plagioclase, biotite, sphene, zircon, epidote, and pyrite of a biotite granodiorite (core sample 9527-2b) obtained from a depth of almost 3 km in Los Alamos Scientific Laboratory's (LASL) deep drill hole GT-2.

Abstract Inshore coral habitats are at high risk of loss due to a combination of climate warming and regional-scale human impacts. As a result, they have undergone significant declines. ... Using high-precision uranium-thorium (UTh) dating, we reconstruct a ~100-year-long history of extensive coral loss, changes in coral community structure ...

Data on modern radiocarbon activity in the old travertine formations of the Pymvashor hydrothermal system were used, in combination with 230 Th/U dating of the travertine, to estimate the 14 C contents of the total dissolved inorganic carbon in the ancient thermal water at the time of precipitation of the travertine (14 C calc).With the known values of 14 …

Abstract. This paper addresses the development of a process to recovery uranium, thorium and rare earth elements from an industrial residue, with a subsequent removal of U and Th from the liquor generated. Sulfuric acid digestion followed by water leaching was found to be the best method to solubilise the metals.

The concentrations of uranium, thorium, barium, nickel, strontium and lead in the samples of the tailings and plant species collected from a uranium mill tailings repository in South China were analyzed. Then, the removal capability of a plant for a target element was assessed. It was found that Phragmites australis had the greatest removal …

Abstract. The U.S. Geological Survey has in preparation a comprehensive volume on the mineralogy of uranium and thorium. This work has been done as part of a continuing systematic survey of data on uranium and thorium minerals on behalf of the Division of Raw Materials, U.S. Atomic Energy Commission. Pending publication of this volume and …

Abstract. This report is part of the National Uranium Resource Evaluation (NURE) Program designed to identify criteria favorable for the occurrence of the world's significant uranium deposits. This project deals specifically with uranium- and thorium-bearing pegmatites in the United States and, in particular, their distribution and origin.

There are several advantages of using thorium as a nuclear fuel compared to uranium. Thorium oxide has a higher melting point (3300ᴼC) compared to uranium oxide (2865ᴼC), and thorium oxide …

Abstract. The uranium-thorium (U-Th) method can constrain the age of cave art by providing dates of formation of calcite deposits from on top of paintings or calcite layers on which paintings were done.

Abstract. The uranium and thorium contents of 199 igneous rocks from a variety of petrographic provinces are here summarized. Data are given for the Mesozoic calcalkalic batholiths of the western United States; volcanic and hypabyssal rocks of the tholeiitic magma type from Hawaii and ia; and effusive calc- alkalic, alkalic, and subsilic …

The determination of activities of thorium, uranium, plutonium, americium, and curium at very low levels has been performed by a new α liquid scintillation system (PERALS, name registered to Ordela, Inc.). The limit of detection has been determined for these nuclides with calculated values often lower than those obtained by other methods, …

Abstract Uranium and thorium are heavy metals, and all of their isotopes are radioactive, so it is impossible to study chemical effects entirely independent of the radiation effects.

Uranium and thorium separation in some rare earth practices outside China. ... Show abstract. The extraction and separation of actinide over lanthanide elements is a key step in the spent fuel reprocessing process, which involves a variety of actinides with different valence states.

Thorium is a naturally occurring, slightly radioactive element. It is widely distributed in nature with an average concentration of 10.5 ppm Th in the upper earth's crust. In general, thorium occurs in …

Abstract. Uranium, thorium and potassium are distinguished in different compartments of the environmental media according to the inputs, the fate and the distribution patterns that occur in the ecosystems. Thus, an understanding of the sources patterns and behaviours of these elements in soils, their rock-soil relationships and …

The Bokan Mountain (Kendrick Bay) uranium-thorium deposits are associated with a Late Jurassic peralkaline granite ring-dike complex. The uranium-thorium deposits form pipe-like bodies along contacts, or occur as pods in en echelon northwest-striking shear zones.

The host intrusive is a multiphased body consisting mainly of riebeckite granite …

DOI: 10.1007/s00204-023-03484-6 Abstract Uranium and thorium are heavy metals, and all of their isotopes are radioactive, so it is impossible to study chemical effects entirely independent of the radiation effects.

Lead from fine surface material is highly radiogenic. An age of 4750 million years has been calculated from the ratio of 207 Pb/ 206 Pb. The concentrations of uranium, thorium, and lead isotopes are consistent with the evolution of lead in a 4700-million-year-old closed system characterized by the ratios of uranium to lead and of thorium to ...

The average and nearly uniform values found in orthoquartzitic, clay-free sands were potassium (as metal) 0-64 0'04 per cent; thorium 1-7 -^ O'l p.p.m.; and uranium 0-45 0-05 p.p.m., giving a Th/U ratio of 3-8 0-8. The Th/U ratio found is very near to that of average igneous rocks and may represent an independent determination of the average ...

Owing to their natural radioactivity, uranium (U) and thorium (Th) play significant roles in environmental sciences for monitoring radiation dose and in geological sciences for understanding sedimentary processes. The Odisha coastal area, in eastern India, is a well-known high background radiation area that is rich in monazites and rutile. …