Petrology and tectonic evolution of late Paleozoic mafic-ultramafic sequences and the Leones Pluton of the Eastern Andean Metamorphic Complex (46-47°S), southern Chile

The metamorphosed mafic-ultramafic sequences of the Eastern Andean Metamorphic Complex outcropping in Patagonian Andes are critical to disclose late Paleozoic tectonic evolution southwestern margin Gondwana. In study area, bodies thrusted onto polydeformed metasedimentary rocks and intruded by mid-Carboniferous composite Leones Pluton. metabasalts (mostly tremolite-chlorite schists amphibolites) show N-MORB BABB chemical affinities pointing that formed part an oceanic crustal section with components marginal basin, emplaced after main pulse Devonian arc magmatism, possibly a retreating convergent margin. Interleaved serpentinites consist serpentine polymorphs (antigorite, lizardite, chrysotile) magnetite, variably distributed minor amounts chlorite, tremolite, traces ilmenite. Serpentinites have high Cr, Ni, Ti, Yb contents, slightly enriched LREE flat HREE patterns noticeable Eu positive anomaly. Mineralogical geochemical features indicate olivine-rich clinopyroxene-spinel-bearing peridotites were newly east-dipping subduction zone. closure basin continued underthrusting juxtaposition within accretionary wedge. cycle finished intrusion subduction-related plutons pluton-driven thermal metamorphism.