A Method for the Simultaneous Analysis of "Water" Content and Oxygen Isotopes in Zircons Based on Large-Scale Secondary Ion Mass Spectrometry

Abstract

A method of simultaneously analyzing the 'water' content and oxygen isotope in zircon based on large-scale secondary ion mass spectrometry is disclosed. The method is based on baking in an instrumentsystem and baking and air exhausting by a circulating titanium pump to reduce an internal background value of an instrument as far as possible, a target made of an alloy material is adopted to reduceimpurity gas introduced from the outside, and liquid nitrogen refrigeration is adopted as assist, and therefore the vacuum degree of a sample cavity is greatly increased, the lower limit of detectionis effectively reduced, and the analysis precision is increased. Based on a high spatial resolution characteristic of a large-scale secondary ion mass spectrometer, microcell in-situ simultaneous analysis of the 'water' content and the oxygen isotope for small zircon particles and other nominally anhydrous minerals is achieved.

Description

Technical field: [0001] The invention relates to the technical field of mineral composition analysis, in particular to a method for simultaneous micro-area in-situ quantitative analysis of "water" content and oxygen isotope in zircon based on large-scale secondary ion mass spectrometry. Background technique: [0002] Nominally anhydrous minerals refer to minerals that do not contain H in the ideal chemical formula, such as olivine, pyroxene, zircon, garnet, and feldspar, but many experiments have shown that their structures contain H, and generally point defects form into mineral crystals. In the earth science community, all H-containing phases are collectively referred to as "water"-containing phases. Because the existence of microstructure "water" will have a very significant impact on the physical and chemical properties of minerals and even rocks, the importance of its absolute content measurement has been widely recognized by the earth science community and has receive...

AI Technical Summary

Problems solved by technology

Turner et al. (2015) have used the large-scale ion probe SHRIMP SI to carry out water content testing research on silicate glass and nominally anhydrous minerals such as pyroxene and olivine, but limited by the vacuum level of the sample chamber, its The detection limit is only 20-40ppm, which is higher than the analytical detection limit of infrared spectroscopy and small ion probe, and the water content of zircon particles is not analyzed

However, CAMECA IMS 1280 and CAMECA IMS 1280-HR are limited in their large sample chamber and high background value, and their wide application has not yet been realized.

Images