Accretion Tectonics in Sabah: Kinabalu Suture and East Sabah accreted terrane

The Kinabalu Suture Zone is an up to 80-km wide belt extending across Sabah from Teluk Darvel via the upper Segama, Telupid, Ranau, Gunung Nungkok, Kota Belud area and Teluk Marudu to Banggi and Balambangaan islands. This belt contains most of the Crystalline Basement, maficsultramafics, Chert-Spilite ophiolite and melange, and olistostromes of Sabah that range in age from Triassic of older to Middle Miilcene. Three collisional rock assemblages can be distinguished: the Late Cretaceous-Paleocene Chert-Spilite formations, and the Paleocene-Oligocene Trusmadi and Crocker formations, and the Oligocene-Middle Miooene Garinono and Kalabakan diamictites/olistostromes. West Sabah is an accreted region that consists of continental margin crust rifted off from the Asian continent, presumably in the vicinity of Hong Kong, and drifted some 750 Ian southward between 32 Ma and 17 Ma through spreading of the South China Basin. In Cretaceous to Paleocene time an oceanic basin existed to the east of Sabah where the Chert-Spilite ophiolite developed This formation apparently experienced subduction as its.melange character suggests. Subsequently, turbidites and mass-flow sandstones of the Paleocene}. Early Miocene Trusmadi-Crocker formations accumulated in the same basin. The approaching East Sabah terrane caused olistostromes and diamictites to develop in the narrowing basin and ultimately squeezed out of the ensuing su~ zone Part of the basinal sediments. The deformation resulted in fault-bounded rock assemblages that were thrusted fan-like in directions perpendicular to the strike of the suture zone. By the end of the Middle Miocene the East Sabah terrane was welded to mainland Borneo. Left-lateral motion along the NW trending Balabac fault caused Banggi island (and Balambangan island?) to rotate counter-clockwise 90-degrees to its present position. The different structural trend of Banggi suggests that it rotated independently from the rest of the East Sabah terrane. A NW -trending fault is postulated between Banggi and Kudat to account for the independent rotation