کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4680710 1634935 2006 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Pb-diffusion in monazite: Constraints from a high-T contact aureole setting
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات علوم زمین و سیاره ای (عمومی)
پیش نمایش صفحه اول مقاله
Pb-diffusion in monazite: Constraints from a high-T contact aureole setting
چکیده انگلیسی

We report measurements of Pb diffusion in natural monazite that was subjected to a static, anhydrous, high-temperature overprint in the contact aureole of the Makhavinekh Lake Pluton (MLP), northern Labrador, Canada. The 1850 Ma monazite grains we studied were reheated to temperatures of 900 ± 25 °C during intrusion of MLP at 1322 Ma. Ion-microprobe depth-profiling reveals the outermost ∼ 0.3 μm of these grains to contain Pb/U gradients that can be modeled as a result of one-dimensional concentration-independent diffusion (i.e., an error-function profile) at 1322 Ma. These gradients are combined with temperature–time histories predicted by a numerical model of conductive heat flow in the contact aureole to calculate Pb diffusion coefficients between 3.2 × 10− 28 and 1.3 × 10− 27 m2/s. This range overlaps with the down-temperature extrapolation of experimental Pb diffusion data obtained under dry conditions confirming the slow diffusivity of Pb in monazite at crustal temperatures and timescales.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Earth and Planetary Science Letters - Volume 250, Issues 1–2, 15 October 2006, Pages 376–384
نویسندگان
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