Concentrations of 13 radionuclides (137Cs, 129I, 60Co, 152Eu, 90Sr, 99Tc, 241Am, 238Pu, 239,249Pu, 234U, 235U, 236U, 238U) were examined in seven species of invertebrates from Amchitka and Kiska Islands, in the Aleutian Chain of Alaska, using gamma spectroscopy, inductively coupled plasma mass spectroscopy, and alpha spectroscopy. Amchitka Island was the site of three underground nuclear test (...

Molybdenum and uranium are redox sensitive elements that experience isotope fractionation in the Earth-surface environment. Recent studies have explored transfer of these fractionated signals subduction zones to arc magmas, but less is known about full variation isotopic tracers mantle, particularly domains mantle may feed hot spots. Here, we present Mo U data for lava samples from Pitcairn, Sa...

The 23 aU/23 $ U ratios for nine bulk chondritic meteorites and a terrestrial basalt were measured. The total range in 235U/235U determined for both total meteorites and for acid leaches was from 137.2 to 138.3 and to within the error limits indistinguishable from normal terrestrial U. The typical errors in a single determination are +6•oo (2aM) for a 2 ng U sample from a chondrite. Taking the ...

Geochemical proxies—such as the isotopic compositions and abundances of redox-sensitive metals, organic biomarkers, sedimentological indicators—can be used qualitatively quantitatively to reconstruct marine redox landscapes through Earth history. Isotopic proxies with residence times longer than ocean mixing times, including uranium (238U/235U, commonly denoted ?238U), are a promising but still...

We measured the neutron scattering intensity ratios from polyethylene (CH2) relative to graphite (C) at several discrete final energies, of narrow widths (approximately 3 eV) between 64 eV and 3 keV. The final energies were selected using a 238U filter. This experiment was carried out to search for any anomaly in the n-p scattered intensities from CH2 caused by the neutron coherence length. The...

Isotopic composition of uranium has previously been used to infer the depositional redox environment ore concentrates and also provide a potential signature inform nuclear forensic investigations. This study evaluates diagnostic power U isotope by investigating (1) heterogeneity compositions in samples collected from same mine and/or vein, (2) influence processing on 238U/235U 234U/238U ratios....

The radioactivity of Greek lignites and their ashes was studied. It was found that the radionuclides in them belong to the uranium series. Fly ashes are relatively rich in radioactivity. Concentrations up to 7 , 1 0 _ 5 g / g and 12 pCi/g were measured for 238U and 226Ra, respectively. The associated hazards from radioactivity escaping from stacks of thermopower plants or when fly ashes are use...