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High‐pressure metamorphic rocks are widely distributed in Cretaceous accretionary complexes throughout Java, Sulawesi (formerly Celebes) and southeast Kalimantan (Indonesian Borneo). Many of these rocks occur as imbricate slices of carbonate, quartzose and pelitic schists of shallow marine or continental margin parentage, interthrust with subordinate basic schists and serpentinite. They are predominantly of low‐to‐intermediate metamorphic grade (300 < T < 550 °C; 4 < P < 12 kbar) and yield mica K–Ar radiometric ages of 110–120 Ma. Metamorphic rocks that exhibit evidence of exhumation from much greater depths (> 60 km), however, are sporadically exposed, usually as tectonic blocks, throughout the Cretaceous accretionary complexes. They include eclogite, garnet–glaucophane rock (P = 18–24 kbar, T = 580–620 °C), and jadeite–garnet–quartz (?coesite) rock (?P > 27 kbar, T = 720–760 °C) in Bantimala, southwest Sulawesi; eclogite and garnet granulite in west central Sulawesi; eclogite and jadeite‐glaucophane‐quartz rock (P ∼ 22 kbar, T ∼ 530 °C) in Luk Ulo, Central Java; and Mg–chloritoid‐bearing whiteschists (P ∼ ?18 kbar) in the Meratus Mountains, southeast Kalimantan. Garnet lherzolites from depths of > 60 km are also associated with schists in east central Sulawesi (P = 22–28 kbar, T = 1000–1100 °C), west central Sulawesi (P = 16–20 kbar, T = 1050–1100 °C); and garnet pyroxenite (P ∼ 20 kbar, T ∼ 850 °C) occurs as blocks with pyrope–kyanite amphibolite, eclogite and blueschist, within Miocene conglomerate in Sabah, northeast Borneo. Many of the metamorphic rocks were probably recrystallized in a north‐dipping subduction zone at the margin of the Sundaland craton in the Early Cretaceous. Exhumation may have been facilitated by the collision of a Gondwanan continental fragment with the Sundaland margin at ca 120–115 Ma.

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The Bantimala Complex of South Sulawesi, Indonesia is an assemblage of northeastdipping tectonically stacked slices. The slices consist mainly of high pressure metamorphic rocks, radiolarian chert, breccia, sandstone and shale, and melange. In order to understand the tectonic evolution of the Bantimala Complex, we have investigated the lithology, age, stratigraphy, structure and relationships of the components. The K-Ar ages of high P-low T metamorphic rocks suggest that an oceanic plate subducted beneath the Sundaland continent during the Late Jurassic or earliest Cretaceous. The subduction ceased during the Albian, and the high pressure schists were exhumed and eroded at the surface before and during the deposition of middle Cretaceous radiolarian chert. The exhumation of the schists was related to the collision of microcontinents derived from Gondwanaland. The Jurassic shallow marine sedimentary rocks in the Bantimala Complex are possibly remnant fragments of the collided microcontinent. Tectonic stacking of the Bantimala Complex was caused by Neogene subduction and collision of another continental fragment further to the east.

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Cretaceous subduction complexes surround the southeastern margin of Sundaland in Indonesia. They are widely exposed in several localities, such as Bantimala (South Sulawesi), Karangsambung (Central Java) and Meratus (South Kalimantan). The Meratus Complex of South Kalimantan consists mainly of mélange, chert, siliceous shale, limestone, basalt, ultramafic rocks and schists. The complex is uncomformably covered with Late Cretaceous sedimentary‐volcanic formations, such as the Pitap and Haruyan Formations. Well‐preserved radiolarians were extracted from 14 samples of siliceous sedimentary rocks, and K–Ar age dating was performed on muscovite from 6 samples of schist of the Meratus Complex. The radiolarian assemblage from the chert of the complex is assigned to the early Middle Jurassic to early Late Cretaceous. The K–Ar age data from schist range from 110 Ma to 180 Ma. Three samples from the Pitap Formation, which unconformably covers the Meratus Complex, yield Cretaceous radiolarians of Cenomanian or older. These chronological data as well as field observation and petrology yield the following constraints on the tectonic setting of the Meratus Complex. (1) The mélange of the Meratus Complex was caused by the subduction of an oceanic plate covered by radiolarian chert ranging in age from early Middle Jurassic to late Early Cretaceous. (2) The Haruyan Schist of 110–119 Ma was affected by metamorphism of a high pressure–low temperature type caused by oceanic plate subduction. Some of the protoliths were high alluminous continental cover or margin sediments. Intermediate pressure type metamorphic rocks of 165 and 180 Ma were discovered for the first time along the northern margin of the Haruyan Schist. (3) The Haruyan Formation, a product of submarine volcanism in an immature island arc setting, is locally contemporaneous with the formation of the mélange of the Meratus Complex.

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