Method and system for carrying out Sr isotope analysis on Sr-rich minerals or rocks

Abstract

The invention belongs to the technical field of isotope analysis, and discloses a Sr isotope analysis method and system for Sr-rich minerals or rocks, and the method comprises the following steps: collecting signals with the mass numbers of 83, 83.5, 84, 85, 86, 86.5, 87 and 88 in to-be-detected minerals; the interference of the Ca / Ar polymer on 84Sr is deducted by detecting the left shoulder position of an overlapping peak; according to the Sr isotope mass fractionation correction factor, 88Sr / 86Sr natural abundance is adopted to carry out exponential normalization quality discrimination correction on the Sr isotope ratio, 87Srt / 86Srt is obtained to trace the geological source of a sample, and the evolutionary history of a shell mantle is revealed. According to the invention, the interference deduction method is optimized, the test process is simplified, and the test result of the standard sample is consistent with the recommended value within the error range.

Description

technical field [0001] The invention belongs to the technical field of isotope analysis, and in particular relates to a method and system for analyzing Sr isotope of Sr-rich minerals or rocks. Background technique [0002] Strontium (Sr) is an alkaline earth metal element with an abundance in the earth's crust of 3.7×10 -2 %, widely exists in various rocks and minerals in nature. Strontium has four isotopes: 84Sr, 86Sr, 87Sr and 88Sr, and their relative abundances are: 0.56%, 9.86%, 7.02% and 82.56%, respectively, and 87Sr is produced by the decay of 87Rb. There are multiple strontium isotope reservoirs in the earth system. After a long geological history and long-term geological evolution, the strontium isotope composition characteristics of different end members are different. By testing the strontium isotope composition in the sample, the sample can be traced The geological origin of the crust and mantle, and then reveal the evolution history of the crust and mantle. ...

AI Technical Summary

Problems solved by technology

[0006] (1) The existing technology does not deduct the interference of Ca / Ar polymers in the process of strontium isotope analysis of strontium-rich minerals, which will greatly reduce the accuracy of strontium isotope test results

[0007] (2) The calculation work involved in strontium isotope research is done by manual calculation, which is arduous and lacks a set of mature and highly automated data processing programs for strontium isotope analysis of strontium-rich minerals

[0009] (1) In order to deduct the interference of the Ca / Ar polymer to the interference of the Sr isotope, the inventor can use two methods for analysis. The first method is to use the high-resolution mode of the instrument to separate the Ca / Ar polymer and the Sr isotope in the mineral , but the high-resolution mode will greatly reduce the sensitivity of the instrument, and Sr is a trace element in most minerals, and low sensitivity will be difficult to measure accurately; the second method is to use the low-resolution mode of the instrument to accurately detect overlapping peaks, which requires a clear understanding Many Ca / Ar polymers interfere with Sr isotopes, and it is also very difficult to accurately determine the test position

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