Geochemical compositions (XRF, LA-ICP-MS, EMPA) and bulk magnetic properties of volcanic rocks used for mapping in the northern Semail ophiolite (Oman)

Lava, dyke and volcanic glass samples from across the northern Semail ophiolite were collected to provide references for geological mapping of the Semail volcanic units. These samples were analysed by various geochemical means to assign them to a volcanic unit. In addition, the bulk rock magnetic properties of a subset of these samples were determined to aid interpretation of existing aeromagnetic data. The whole-rock major element and select trace element (Ba, Sr, Zr, Y, Zn, Cu, Ni, Cr, V, Sc) composition of the majority of these samples was determined by X-Ray fluorescence (XRF) at ETH Zürich using a PANalyticalTM Axios wavelength-dispersive instrument. Trace elements in a subset of these samples were further analysed by pressed-powder-pellet laser-ablation inductively-coupled plasma spectrometry (PPP-LA-ICP-MS) using a GeoLas-Pro 193 nm ArF Excimer™ laser system in combination with an ELAN DRC-e™ quadrupole mass spectrometer at the University of Bern. Where necessary for unit assignment, igneous clinopyroxenes in another subset of samples were measured by Electron microprobe (EMP) on a JeolTM JXA-8200 EMP at the University of Bern. A set of volcanic glasses were also analysed by EMP on the same instrument. Bulk magnetic susceptibility was determined by two methods: a handheld Exploranium KT-5 kappameter and a desktop Magnon kappameter at the Institute for Rock Magnetism (IRM), University of Minnesota. Duplicate analyses of the same samples with both instruments indicates good comparability between the two datasets. Natural remanent magnetization (NRM) was determined on a 2G Enterprises 760 RF TM SQUID superconducting rock magnetometer at the IRM.