Comments on “Corundum-bearing garnet peridotite from northern Dominican Republic: A metamorphic product of an arc cumulate in the Caribbean subduction zone,” by Hattori et al. [Lithos 114 (2010) 437-450]

The Cuaba Gneiss in northern Dominican Republic hosts an unusual suite of Grt-ultramafites. Two hypotheses for their origin are distinguished by the depth of crystallization of an igneous protolith. In the first hypothesis the protolith crystallized under ultra high pressure (UHP) magmatic conditions (> 3.2 GPa) in the field of stability for Grt + Spl + Crn. The protolith was then modified by subsolidus processes. In a new hypothesis the protolith crystallized under low pressure (LP) magmatic conditions (< 1.1 GPa) in the field of stability for plagioclase. Grt + Crn was produced during prograde metamorphism. The LP hypothesis depends on a small Eu anomaly, limited fluid interaction, REE modeling, and a magmatic composition for clinopyroxene. Arguments against the LP hypothesis address, (1) the source of the Eu anomaly, (2) the use of clinopyroxene in assessing provenance and modeling REEs, (3) the proposed prograde mineral reactions, and (4) thermodynamic calculations.