(Table A1) Chemical composition of abyssal peridotites from ODP Hole 153-920

• Main Authors: Lee, Cin-Ty Aeolus, Brandon, Alan D, Norman, Marc D
• Format: Dataset
• Language: English
• Published: PANGAEA 2003
• Subjects: 153-920; Aluminium oxide; Calcium oxide; Calculated; COMPCORE; Composite Core; DSDP/ODP/IODP sample designation; Iron oxide; FeO; Joides Resolution; Leg153; Magnesium oxide; Manganese oxide; North Atlantic Ocean; Ocean Drilling Program; ODP; Phosphorus pentoxide; Potassium oxide; Sample code/label; Silicon dioxide; Sodium oxide; Sum; Titanium dioxide; Vanadium; X-ray fluorescence (XRF); North Atlantic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.708432; https://doi.org/10.1594/PANGAEA.708432

The compatibility of vanadium (V) during mantle melting is a function of oxygen fugacity (fO2): at high fO2's, V becomes more incompatible. The prospects and limitations of using the V content of peridotites as a proxy for paleo-fO2 at the time of melt extraction were investigated here by assessing the uncertainties in V measurements and the sensitivity of V as a function of degree of melt extracted and fO2. V-MgO and V-Al2O3 systematics were found to be sensitive to fO2 variations, but consideration of the uncertainties in measurements and model parameters indicates that V is sensitive only to relative fO2 differences greater than ~2 log units. Post-Archean oceanic mantle peridotites, as represented by abyssal peridotites and obducted massif peridotites, have V-MgO and -Al2O3 systematics that can be modeled by 1.5 GPa melting between FMQ - 3 and FMQ - 1. This is consistent with fO2's of the mantle source for mid-ocean ridge basalts (MORBs) as determined by the Fe3+ activity of peridotitic minerals and basaltic glasses. Some arc-related peridotites have slightly lower V for a given degree of melting than oceanic mantle peridotites, and can be modeled by 1.5 GPa melting at fO2's as high as FMQ. However, the majority of arc-related peridotites have V-MgO systematics overlapping that of oceanic mantle peridotites, suggesting that although some arc mantle may melt under slightly oxidizing conditions, most arc mantle does not. The fact that thermobarometrically determined fO2's in arc peridotites and lavas can be significantly higher than that inferred from V systematics, suggests that V retains a record of the fO2 during partial melting, whereas the activity of Fe3+ in arc peridotitic minerals and lavas reflect subsequent metasomatic overprints and magmatic differentiation/emplacement processes, respectively. Peridotites associated with middle to late Archean cratonic mantle are characterized by highly variable V-MgO systematics. Tanzanian cratonic peridotites have V systematics indistinguishable from post-Archean ...