Читать книгу Isotopic Constraints on Earth System Processes - Группа авторов - Страница 49

Each diffusion couple was extracted and sectioned down its vertical axis, mounted in a 1‐inch epoxy puck, and polished to 0.25 μm. After mounting, we measured the length of the diffusion couples and note that each one had compressed from an initial length of 10.4 mm down to about 6.6 mm. Axis‐parallel major‐element diffusion profiles were measured from end‐to‐end with a JEOL JXA‐8200 SuperProbe at Lawrence Livermore National Laboratory using a 15 nA beam current rastered at 12000× magnification (12 μm × 9 μm beam dimensions) with an accelerating voltage of 15 kV. Sodium was measured first at each spot to mitigate effects of Na migration. All electron probe data are provided as an Excel file in the Electronic Supplement.