Edax genesis software

After fluorescence microscopy, each section was dipped in a dehydration series of 50%, 80% and 100% ethanol solutions (balance Milli‐Q water). The sample was then mounted on an SEM sample holder with double‐sided carbon tape, sputter‐coated with 5 nm of Pt/Pd (EMS 150 T S Metal Sputter Coater, Electron Microscopy Science, Hatfield, PA), and loaded into a JEOL JSM 7900F Schottky FE‐SEM. Using the Zeiss SmartSEM software, secondary electron images were collected at a voltage of 12 kV using an Everhart–Thornley detector. The voltage was increased to 20 kV for elemental analysis via an Oxford Ultim Max EDS Detector. Elemental abundances of S, Fe, K, Ca, Mg, Ti, Na, Si, Al, O and C were acquired, and data were processed with the EDAX Genesis software (Ametek, Berwyn, PA). Elemental maps were used for visualization purposes, supported by quantitative area‐based scans to inform mineral identification by X‐ray diffraction (XRD).

FE-SEM and STEM was performed using a Hitachi S-5200 (Hitachi High-Tech Corp., Tokyo, Japan) equipped with detectors for secondary and transmitted electrons at 4 kV and 30 kV acceleration voltage, respectively. Micrographs using backscattered electrons were recorded with a Hitachi SU 5000 FESEM. An EDAX Phoenix X-ray-detector system attached to the Hitachi S-5200 was used to record elemental maps at a pixel resolution of 512 × 400 and a dwell time of 200 µs per pixel leading to 88 full scans per hour. A full spectrum was recorded and stored for every pixel (spectral mapping). At each scan, spectra were integrated for every pixel allowing for standard-less background corrected calculation of atomic ratios for selected regions. For bulk samples we used the ZAF mode and for thin sections the Mthin mode following the method of Zaluzec (1980) as implemented in the EDAX Genesis software (Ametek GmbH, Meerbusch, Germany).