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Thorium, 90Th. face-centred cubic (fcc) Thorium is a weakly radioactive metallic chemical element with the symbol Th and atomic number 90. Thorium is silvery and tarnishes black when it is exposed to air, forming thorium dioxide; it is moderately hard, malleable, and has a high melting point. Thorium is an electropositive actinide whose ...
EARTH AND PLANETARY SCIENCE LETTERS 4 (1968) 17-21. NORTH-HOLLAND PUBLISHING COMP., AMSTERDAM IONIUM/THORIUM GEOCHRONOLOGIES Edward D. GOLDBERG Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, USA Received 12 March 1968 Rates of sedimentation in the Pacific, Indian and Arctic oceans as determined by …
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Ionium「」,,「Ionium–Thorium Dating」—— -230（Ionium）-232（Thorium）,「 （ ： Ionium–thorium dating ） 」 。
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Ionium was a name given early in the study of radioactive elements to the 230 Th isotope produced in the decay chain of 238 U before it was realized that ionium and thorium are chemically identical. The symbol Io was used for this supposed element. The name is still used in ionium–thorium dating.
significance in ionium-thorium dating. This is defined as excess thorium-230 because its abundance exceeds the equilibrium amount that should be present. With time, the excess decays away and the age of any horizon in a core sample can be estimated from the observed thorium-230-to-thorium-232 ratio in the seawater-derived component of the core.
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207, and 206); and the thorium, radiothorium, and ionium (thorium-230). The chemical similarity in these cases was even greater than that among the rare earths, Soddy notes, and he was particularly impressed by the inability of Auer von Welsbach, an expert in rare earth chemistry, to separate thorium and ionium. Here Soddy
The preparation of ionium described by Prof. Butherford in the footnote consisted of a mixture of the oxides of ionium and thorium. The percentage of ionium oxide in the preparation is not known. It can be calculated, however, provided we know both the period of ionium and the number of a-particles emitted by 1 grm. of the substance per second.
thorium (Th), radioactive chemical element of the actinoid series of the periodic table, atomic number 90; it is a useful nuclear reactor fuel. Thorium was discovered (1828) by Swedish chemist Jöns Jacob Berzelius.It is silvery white but turns gray or black on exposure to air. It is about half as abundant as lead and is three times more abundant than uranium in Earth's crust.
Ionium was a name given early in the study of radioactive elements to the 230 Th isotope produced in the decay chain of 238 U before it was realized that ionium and thorium are chemically identical. The symbol Io was used for this supposed element. (The name is still used in ionium–thorium dating.) Thorium-231. 231 Th has 141 neutrons.
2. Theoretical models It is well known that ionium activity is related to uranium activity by the relation: (Io) = (lo)o e-~lt + (U) (1 - e ~, r) (1 )t In pelagic sediments ionium concentration is greater than the secular equilibrium values. By definition excess ionium is: (lo)ex (Io) - (U) (lo)o ex e-t`t (2) If (lo)o ex is constant during ...
The ratio of 3% (thorium cycle) to 33% (LWR) is 1:11, which would mean the thorium cycle is producing 9% as much actinide waste, assuming that only 237 Np is the waste stream and not 231 Pa or others. GNEP: Constituents of Used Nuclear Fuel (from LWR) says …
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Ionium-thorium dating is a related process, which exploits the insolubility of thorium (both 232 Th and 230 Th) and thus its presence in ocean sediments to date these sediments by measuring the ratio of 232 Th to 230 Th. Both of these dating methods assume that the proportion of 230 Th to 232 Th is a constant during the time period when the ...
SPECIAL RADIOISOTOPES FOR POWER: AVAILABILITY AND APPLICATIONS OF THORIUM- 230 (IONIUM) FROM URANIUM ORE MILLS. Technical Report Roann, C A. Earlier reports reviewing the properties of U/sup 232/ (and its daughter Th/sup 228/) emphasized favorable comparisons with other radioisotopic heat sources. It was also shown that Th/sup 230 ...
special radioisotopes for power: availability and applications of thorium- 230 (ionium) from uranium ore mills Technical Report Roann, C Earlier reports reviewing the properties of U/sup 232/ (and its daughter Th/sup 228/) emphasized favorable comparisons with other radioisotopic heat sources.
Thus radiothorium, ionium, thorium, uranium-X 1, and radioactinium are a group of isotopic elements, the calculated atomic masses of which vary from 228 to 234. They all occupy the same place in the periodic table, and are chemically indistinguishable.
Ionium definition is - a natural radioactive isotope of thorium having a mass number of 230.
Ionium/thorium geochronogies and natural radioactive species The phillipsites in the north Pacific core analyzed by BEBSAT and GOLDBEBC (1969) maintained the same Th-230/Th-232 values for a given level as did the <2 p, fraction or the acid leachate of the sediment sample.
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The ionium/thorium method of dating assumes that the proportion of thorium-230 to thorium-232 is a constant during the time period that the sediment layer was formed. Likewise, both thorium-230 and thorium-232 are assumed to precipitate out in a constant …
The ionium/thorium method for determining the rates of accumulation of marine sediments was applied to a group of deposits from the Pacific, Atlantic, and Indian Oceans. The thorium isotopes which were accommodated in authigenic minerals (presumably derived from sea water) were obtained through a hot hydrochloric acid leaching of the sample.
It is demonstrated that the uranium/thorium ratio in sea water may change with time. Consideration is given to the conditions under which the ionium/thorium ratio may be utilized for determination of age and, consequently, for the determination of the rate of sedimentation.
A related method is ionium—thorium dating, which measures the ratio of ionium thorium to thorium in ocean sediment. Radiocarbon dating is also simply called Carbon dating. Carbon is a radioactive isotope of carbon, with a half-life of 5, years, [25] [26] which is very short compared with the above isotopes and decays luck nitrogen.
A method has been developed for determining uranium, thorium, and ionium (Th/sup 230/) in sea silt from a single sample. The completeness of isolation and radiochemical purity of thorium isotopes have been tested by means of tracers. The method has been proved on samples of sea silt as well as of rocks, ores, and minerals.
The rate of deposition of deep-sea deposits collected at the depths of 6215 to 8450 m in the western part of the North Pacific Ocean was estimated by means of the ionium/thorium ratio. The ratio was determined by an alpha-ray spectrometer. Results showed the rate of 0.5 to 0.8 mm/103 yr for the upper 10-cm layer below the sea bottom.
Ionium is thorium-230, which is part of the natural decay chain of uranium-238, which is rather abundant. Thus one could expect to find ionium in uranium tailing piles. When ionium is exposed to neutrons, it first forms protactinium-231, and then another neutron absorption forms uranium-232.
Ionium definition: a naturally occurring radioisotope of thorium with a mass number of 230 | Meaning, pronunciation, translations and examples
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Ionium-thorium dating physics Britannica. Ionium-thorium dating, method of establishing the time of origin of marine sediments according to the amount of ionium and thorium they contain. Because uranium compounds are soluble in seawater, while thorium compounds are quite insoluble, the thorium isotopes produced by the decay of uranium ...
of thorium content in clayey and detrital min-erals would be about 4: 1. Therefore, even if some leaching of thorium from detrital mate-rials would have occurred, the ratio of ionium and thorium would not have varied so much. 8. E. D. Goldberg, C. Patterson, T. Chow, Proc Seco}d U.N. Intern. Conf . on Peacef ul Uses of Atomic ECnergy 18, 347 ...
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