کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6438193 | 1638009 | 2015 | 20 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Discriminating secondary from magmatic water in rhyolitic matrix-glass of volcanic pyroclasts using thermogravimetric analysis
ترجمه فارسی عنوان
ثانویه تشخیصی از آب مغناطیسی در شیشه ماتریس ریولیتی پری کلاست های آتشفشانی با استفاده از تجزیه و تحلیل ترموگرافی
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موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
ژئوشیمی و پترولوژی
چکیده انگلیسی
Pyroclasts from explosive eruptions, such as the 1060 CE explosive Glass Mountain eruption of Medicine Lake volcano, California, contain large amounts of water. This may be the consequence of diffusive rehydration of the volcanic glass by meteoric (secondary) water after the eruption. Discriminating between magmatic and secondary water in the matrix glass of pyroclasts is important, because the degassing of magmatic water affects the intensity of volcanic eruptions. Such discrimination has remained a challenging problem, especially because some aspects of water diffusion in silicate glasses at low temperatures and atmospheric pressure remain poorly constrained. We used thermogravimetry to analyze the loss of water from natural volcanic glasses and glasses that were hydrated in the laboratory at magmatic temperatures and pressures. Numerical modeling of diffusive water loss during thermogravimetric analyses accounted for the interconversion of molecular water (H2Om) and hydroxyls groups (OH), and indicates that Glass Mountain pumices contain 0.2-0.5Â wt% primary water, but gained 1-2Â wt% of meteoric water by diffusive rehydration during the past 950Â years. These results confirm that the majority of magmatic water is lost from the magma during explosive eruptions. Furthermore, the integration of thermogravimetric analysis and numerical modeling facilitates discrimination between the magmatic and secondary water content of volcanic glasses.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Geochimica et Cosmochimica Acta - Volume 148, 1 January 2015, Pages 457-476
Journal: Geochimica et Cosmochimica Acta - Volume 148, 1 January 2015, Pages 457-476
نویسندگان
Thomas Giachetti, Helge M. Gonnermann, James E. Gardner, Thomas Shea, Andrew Gouldstone,