According to their geochemical signatures, the eclogites formed from typical mid-ocean ridge basalts (MORB), whereas the blueschists had seamount-like protoliths and the eclogite-facies peridotites apparently stem from depleted, MORB-source mantle. Peak metamorphic conditions of the high-pressure rocks occurred at 1.8 GPa and 600 ☌, which corresponds to a maximum burial depth of about 60 km. The Lu-Hf garnet-whole rock ages of a blueschist, a metapelite, and an eclogite cluster at ca. The metamorphic Raspas Complex of southwest Ecuador comprises blueschists, eclogites, and high-pressure ultramafic and sedimentary rocks. The spatially close association of MORB-type eclogite, seamount-type blueschist, serpentinized peridotite, and metasediments points to an exhumed high-pressure ophiolite sequence. We suggest that this section became dismembered from the slab during burial at great depth-perhaps as a consequence of scraping off the seamounts. That these rocks were subjected to similar peak PT conditions contemporaneously suggests that they were subducted together as an essentially complete section within the slab.

The geochemical signatures of the eclogites suggest that their protoliths were typical mid-ocean ridge basalts (MORB), whereas the blueschists exhibit seamount-like characteristics, and the eclogite-facies peridotites seem to represent depleted, MORB-source mantle. Peak metamorphic conditions in the eclogites reached 1.8 GPa at 600☌, corresponding to a maximum burial depth of ~60 km. The Lu–Hf ages of a blueschist, a metapelite, and an eclogite overlap at around 130 Ma and date high-pressure garnet growth. The metamorphic Raspas Complex of southwest Ecuador consists of high-pressure mafic, ultramafic, and sedimentary rocks.

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