Miocene tectonic of the Southeast Arm of Sulawesi, Indonesia: Based on petrology data, geochemistry, and ⁴⁰Ar/³⁹Ar geochronology of metamorphic rocks from Rumbia Complex

Neogene sediment provenance and paleogeography of SE Sulawesi, Indonesia

“…Hamilton (1979) observed that “gabbro, diabase, basalt, spilite, amphibolite and greenschist” are of minor volume in the SE Arm and “the relative scarcity of mafic rocks in the SE Arm pose problems,” although ultramafic rocks are abundant. Isotopic dating of the Eastern Sulawesi metamorphic rocks (ESMC), which include blueschists, in the SE Arm suggest Oligo‐Miocene subduction‐related metamorphism (Helmers et al, 1989; Mawaleda et al, 2018; Parkinson, 1996; Wijbrans et al, 1994).…”

“…This is supported by the heavy mineral assemblages, particularly glaucophane and lawsonite that represent a HP-LT (blueschist) metamorphic rock source. These minerals were probably derived from the Mekongga and Rumbia metamorphic complexes, in which blueschists are exposed (de Roever, 1950(de Roever, , 1956Helmers et al, 1989;Mawaleda et al, 2016Mawaleda et al, , 2018Wijbrans et al, 1994). Garnet could have been derived from a multitude of metamorphic rocks, as well as garnet-bearing peridotites reported in Central Sulawesi close to the Palu-Koro Fault and in the East Arm where they are associated with the ophiolite (Kadarusman & Parkinson, 2000;Parkinson, 1996).…”