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今年六月图格林諾夫专家在科学院地貭所作了关于絕对年龄測定的报告。首先专家談到“粗铅法”测定古老岩浆(热液)成因的方鉛矿和近海沉积碳酸盐絕对年龄的可能性。粗鉛法测定年龄的依据是:在矿石和岩石中所谓普通鉛是由四种同位素所組成,即Pb~(204),Pb~(206),Pb~(207)和Pb~(208),其中Pb~(204)是非放射性成因的鉛,从地壳形成时起,它的含量从未发生任何变化;而Pb~(206),Pb~(207)和Pb~(208)是放射性成因的,由于U,Th的蛻变,它們的量一直在不断增长。如果将鉛矿床矿石中鉛的同位素比值Pb~(206)/Pb~(204),Pb~(207)/Pb~(204)和Pb~(208)/Pb~(204)作一对比,那么在大多数情况下可以发現一个明显的規
In June this year, Tu Greeninov experts made a report on the absolute age determination at the Academy of Sciences. First, experts talked about the possibility of determining the absolute age of galena and offshore sedimentary carbonate by the “crude lead” method for determining the origin of ancient magmas (hydrothermal fluids). The determination of the age by the crude lead method is based on the fact that the so-called common lead in ores and rocks consists of four isotopes: Pb 204 Pb 206 Pb 277 Pb 208 Pb, Lead (204) is a non-radioactive lead, and its content has never changed since crust formation. Pb ~ (206), Pb ~ (207) and Pb ~ (208) Due to the transformation of U, Th, their volume has been growing. If the lead isotopic ratios Pb ~ (206) / Pb ~ (204), Pb ~ (207) / Pb ~ (204) and Pb ~ (208) / Pb ~ (204) in the lead ore ore are compared, In most cases one obvious rule can be found