X-Ray fluorescence (XRF) scans were carried out for core GeoB24351-1 (Gelendzhik MV; 0-284 cm) in 10 mm steps downcore on the split core surface of the archive half with the XRF Core Scanner III (AVAATECH Serial No. 12) at MARUM – Center for Marine Environmental Sciences in Bremen. To avoid contamination of the XRF measurement unit and the desiccation of the sediment, the split core was covered with a 4 µm thin SPEXCerti Ultralene1 foil. Reported data was acquired with a SGX Sensortech Silicon drift detector (Modul S SiriusD®D65133Be-INF with 133 eV X-ray resolution), a Topaz-X High-Resolution Digital MCA, and an Oxford Instruments 100 W Neptune X-Ray tube with rhodium (Rh) target material. Data were obtained during three runs at 50 kV (1st run), 30 kV (2nd run) and 10 kV (3rd run). Processing of raw data took place by the analysis of X-ray spectra by an iterative least square software package from Canberra Eurisys (WIN AXIL).

Scanner: AVAATECH (Serial No. 12)X-ray tube: Oxford Instruments 100W Neptune Rh X-ray tubeX-ray detector: SiriusSD D65133BE-INFStep size: 10 mmSlit down-core: 10 mmSlit cross-core: 12 mmX-ray tube settings: 1st run: 50 kV; 0.5 mA; 8 sec. Cu filter2nd run: 30 kV; 0.6 mA; 8 sec. Pd thick filter3rd run: 10 kV; 0.05 mA; 8 sec. no filterProcessing model: 1st run: 50 kV; Averaged dead time: 29%2nd run: 30 kV; Averaged dead time: 27%3rd run: 10 kV; Averaged dead time: 27%Data quality check of processed data at MARUM XRF Core Scanner Lab:Data from listed elements are reliable for scientific publication:1st run: Ba, (Sr, Zr, Rb, Br)2nd run: Br, Sr, Zr, Rb3rd run: Al, Si, S, K, ca, Ti, Mn, FeData from listed elements are NOT reliable for scientific publication:1st run: Mo, Ag, Sn, Te2nd run: Ni, Cu, Zn, Ga, (Nb, Mo, Pb), Bi3rd run: P, Cl, Rh, Cr, MgNotes (scatter & escape peaks, elements below detection limit, etc.):Sediment surfaces are very poor and not really suitable for XRF scanning (all:uneven/bumpy surfaces, x to y cm pebbles, holes, and cracks). Therefore highlyrecommended to (only) work with elemental ratios from the acquired datasets.Please also note: Ba: small peaks only, general low total counts; (Sr,Rb,Zr,Br)**: better in30 kV run; (Nb, Mo, Pb): please validate the higher peaks standing out from a differentchemical method