Inter-comparison of XRF core scanning results from IODP Site 346-U1424 and 346-U1425 from 7 labs

Over the course of four years (2014 to 2017), the set of seven u-channels was shipped around the world to seven labs with XRF scanners including, in no particular order, the Kochi Core Center at Kochi University (Japan), IODP Core Repository at Texas A&M University (U.S.A.), Nanjing Normal University (China), Rosenstiel School of Marine and Atmospheric Science at the University of Miami (U.S.A.), ETH Zurich (Switzerland), Woods Hole Oceanographic Institution (U.S.A.), and the Royal Netherlands Institute of Sea Research (The Netherlands). We intentionally do not identify which lab generated which scans, as many of the variables (e.g., X-ray tube aging, detector aging, and/or dehydration of the core material) could affect any instrument at various times or be exacerbated during the transit between labs. Instead, we label the XRF scans #1-#7 in the order in which they were scanned. The labs used various types and different generations of XRF scanning instruments (4 Avaatech Core Scanners, 2 ITRAX Core Scanners, and 1 Geotek Core Scanning Logger) with different X-ray sources (Rhodium, Molybdenum). Three of the labs scanned the cores at two or three excitation energies (e.g., 10 kV, 30 kV, and 50 kV). Each lab reported a different suite of elements, but all included Ca, Fe, K, Mn, Si, Sr, Ti, and Zr. Six labs also reported Al, Br, Cr, Cu, Ni, Pb, Rb, S, and Zn and five labs reported and Ba, Cl, Ga, Mo, V, and Y.