کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
6439066 1638029 2014 13 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Radiogenic Ar retention in residual silica from acid-treated micas
ترجمه فارسی عنوان
رادیوژنیک با استفاده از سیلیکات باقی مانده از مایکاها تحت درمان با اسید ذخیره می شود
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات ژئوشیمی و پترولوژی
چکیده انگلیسی
Our results indicate that the reaction of micaceous sedimentary and diagenetic clay minerals (illite, glauconite) with acid produces microporous silica that retains a great fraction of the initial argon, releasing potassium to the solution. In all tested cases the evolution of K-Ar isotope ages followed the very same pattern: the apparent K-Ar isotope age increased enormously after acid treatment and dropped significantly after silica removal (with hot Na2CO3), but never decreased lower than the initial K-Ar isotope age of the untreated sample. The amorphous silica content and the apparent K-Ar age increased with the acid reaction time. Using the molecular dynamics simulations, the clay-acid reaction by-product was shown to bend and wrap, producing three-dimensional, protonated and hydrated silica. As a consequence of dramatically different hydration energies of Ar and K, potassium is instantaneously released and hydrated outside the residual structure while Ar atoms remain inside the silica network, adsorbed on the surface. This is, to our knowledge, the first experimental evidence that the excess argon can be retained in solid mineral reaction products formed under pressure and temperature close to those of the Earth surface (1 atm, <80 °C).
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Geochimica et Cosmochimica Acta - Volume 128, 1 March 2014, Pages 236-248
نویسندگان
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