{"title":"Application of Proxy Minerals for Evaluation of the Oxygen Isotope Composition of Felsic Melts","authors":"E. O. Dubinina, L. Ya. Aranovich","doi":"10.1134/S0869591123060073","DOIUrl":null,"url":null,"abstract":"<div><p>The problems associated with the use of quartz and zircon as proxy minerals for the reconstruction of δ<sup>18</sup>O values in acidic melts are considered. It is shown that the correction values Δ(<i>Qz</i>–R) and Δ(R–<i>Zrn</i>) used for the reconstructions are not strictly constant and depend on the mineral composition of the rock and the closure temperature of the oxygen isotopic system of the proxy mineral (<i>T</i><sub>q</sub>, <i>T</i><sub>z</sub>–closure temperature of quartz and zircon, respectively). The applicability of quartz was estimated using an equation for Δ(<i>Qz</i>–R) calculation, which takes into account <i>T</i><sub>q</sub> and the mineral composition of rocks. Using the leucogranites of the Raumid massif (South Pamirs) as an example, it was shown that this correction can be approximated by constant value only under definite conditions. The value of Δ(R–<i>Zrn</i>) was estimated using approach based on calculating the weighted average fractionation coefficient and independent estimates Tz using a zirconium thermometer. It was shown for leucogranite porphyries of the Omsukchan trough that this correction for identical rocks varies from 1.3 to 1.9 ‰, unlike Δ(R–<i>Zrn</i>) = 2.1 determined by the dependence on the SiO<sub>2</sub> content (Lackey et al., 2008). The advantages and limitations on the application of quartz and zircon as proxy minerals have been analyzed.</p></div>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"31 6","pages":"664 - 673"},"PeriodicalIF":1.0000,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1134/S0869591123060073.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Petrology","FirstCategoryId":"89","ListUrlMain":"https://link.springer.com/article/10.1134/S0869591123060073","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOCHEMISTRY & GEOPHYSICS","Score":null,"Total":0}
引用次数: 0
Abstract
The problems associated with the use of quartz and zircon as proxy minerals for the reconstruction of δ18O values in acidic melts are considered. It is shown that the correction values Δ(Qz–R) and Δ(R–Zrn) used for the reconstructions are not strictly constant and depend on the mineral composition of the rock and the closure temperature of the oxygen isotopic system of the proxy mineral (Tq, Tz–closure temperature of quartz and zircon, respectively). The applicability of quartz was estimated using an equation for Δ(Qz–R) calculation, which takes into account Tq and the mineral composition of rocks. Using the leucogranites of the Raumid massif (South Pamirs) as an example, it was shown that this correction can be approximated by constant value only under definite conditions. The value of Δ(R–Zrn) was estimated using approach based on calculating the weighted average fractionation coefficient and independent estimates Tz using a zirconium thermometer. It was shown for leucogranite porphyries of the Omsukchan trough that this correction for identical rocks varies from 1.3 to 1.9 ‰, unlike Δ(R–Zrn) = 2.1 determined by the dependence on the SiO2 content (Lackey et al., 2008). The advantages and limitations on the application of quartz and zircon as proxy minerals have been analyzed.
期刊介绍:
Petrology is a journal of magmatic, metamorphic, and experimental petrology, mineralogy, and geochemistry. The journal offers comprehensive information on all multidisciplinary aspects of theoretical, experimental, and applied petrology. By giving special consideration to studies on the petrography of different regions of the former Soviet Union, Petrology provides readers with a unique opportunity to refine their understanding of the geology of the vast territory of the Eurasian continent. The journal welcomes manuscripts from all countries in the English or Russian language.