On the accumulation of helium in geological time
| Autor: | Robert John Strutt |
|---|---|
| Rok vydání: | 1908 |
| Předmět: | |
| Zdroj: | Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character. 81:272-277 |
| ISSN: | 2053-9150 0950-1207 |
| DOI: | 10.1098/rspa.1908.0079 |
| Popis: | In a former paper I gave an account of experiments on the presence of helium in a variety of the common minerals of the earth’s crust. The conclusion arrived at was that the quantity of helium is, in general, determined by the traces of radio-active elements present. The minerals investigated were mostly of palæozoic age, and little attention was paid to the effect of geological age on helium content. If, however, the accepted theory of the progressive accumulation of helium in minerals by radio-active change is correct, it is evident that geological age must be all-important. In the present paper, the subject is considered from that point of view. There is some difficulty in finding suitable material for comparing the helium content of minerals with their geological age. To make such a comparison advantageously, it is necessary to obtain minerals from a very great range of geological horizons, so that the oldest minerals considered shall be many times older than the youngest. Thus it becomes imperative to get material from the secondary and tertiary strata. Most of the constituents of these strata are unsuitable. For instance, derivative materials like clay and sand must be rejected, because they have presumably been accumulating helium long before they were laid down in their present stratigraphical position. The chemical precipitates like rocksalt and gypsum are so free from radio-active constituents that accurate measurements of the helium in them are very difficult; while limestones are, in a lesser degree, open to the same objection. |
| Databáze: | OpenAIRE |
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