Structural basin

Geology

Foreland basin

Diachronous

Late Miocene

Pleistocene

Stratigraphy

Paleontology

Unconformity

Neogene

Zircon

Subduction

Tectonics

Sedimentary rock

Molasse

Journal of Asian Earth Sciences

Over the past century, a wide variety of poorly dated sediments that unconformably overlie pre-Neogene rocks in Sulawesi have been assigned to the Celebes Molasse and interpreted as post-orogenic rocks deposited after a major collision. New data from fieldwork and laboratory studies, including mineralogical, palaeontological and zircon geochronological analyses, provide the basis for a new Neogene stratigraphy and show that sediments assigned to the Celebes Molasse have significant variations in age, environment of deposition, composition and sedimentation history. Identified unconformities in the (1) Early Miocene (c. 23 Ma), (2) Middle Miocene (c. 15 Ma), (3) Mio-Pliocene (c. 6–5.3 Ma), and (4 and 5) Pleistocene (c. 1.8 and 0.1 Ma) separate Lower Miocene, Middle to Upper Miocene, Pliocene, Pleistocene and Holocene mega-sequences. These mega-sequences resulted from Early Miocene collision followed by extension, driven by subduction rollback, causing both uplift and subsidence, in contrast to previous interpretations of multiple collisions.

The Celebes Molasse: A revised Neogene stratigraphy for Sulawesi, Indonesia