Müller, Samuel; Garbe-Schönberg, Dieter; Koepke, Jürgen; Hoernle, Kaj (2021): Petrographic key parameter, EPMA data, LA-ICP-MS data, for plagioclase and clinopyroxenen of 39 gabbro samples form the Oman Ophiolite (Wadi Gideah Transect) [dataset bundled publication]. PANGAEA, https://doi.org/10.1594/PANGAEA.934706

Here we present a profile of 39 gabbros through the plutonic section of the Oman ophiolite paleocrust (Wadi Gideah Transect; Wadi Tayin block). Major and trace element core compositions for co-existing plagioclase and clinopyroxene progressively evolve up section from layered gabbros through foliated gabbros up to the varitextured gabbros. Calculated parental melts correspond to typical Oman MORB but reveal differences in the plagioclase-clinopyroxene equilibrium and crystallization style along the profile. Layered gabbro mineral cores have crystallized under equilibrium and stable boundary conditions. Rims show a pronounced inverse zonation of plagioclase Ca# and, to some extent, of clinopyroxene Mg#. Contrastingly, incompatible trace elements indicate progressive fractionation from the core to the rim and up section. For regression of the temperature inversion, we wrote a custom R script (https://doi.org/10.5281/zenodo.5702686) calling the MASS::rlm function to perform an iterated re-weighted least squares (IWLS) robust linear fit between REEs in the Ln(Dj)-A and Bj-1000 space calculated following Sun and Liang (2017, https://doi.org/10.1007/s00410-016-1326-9). We create an in situ crystallization-temperature depth profile through the lower Oman paleocrust. The estimated temperatures are consistent with temperatures established based on the plagioclase anorthite content, revealing a relationship of T-REE-An [°C] = 6.1 ± 0.2 * An + 706 ± 19. Crystallization temperatures of the layered gabbros cover a narrow median range of 1216 ± 14 °C. Considerable temperature variability of 1077 to 1231 °C is observed for the upper gabbros, featuring a thermal minimum within the foliated gabbros. This dataset includes petrographic descriptions for all 39 samples, average values for EPMA measurements, spot and median data for LA-ICP-MS measurements, the associated standard deviations, related quality control parameters, and calculated REE-temperatures.