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Upper Triassic carbonate deposits of Seram (Indonesia): palaeogeographic and geodynamic implications |
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Published in | Palaeogeography, Palaeoclimatology, Palaeoecology. 2004, vol. 206, no. 1-2, p. 75-102 | |
Abstract | The Upper Triassic limestones of central and western and Seram, were deposited on an extensive carbonate platform, already identified in various localities all around the Banda Sea: Sinta Ridge, central–east Sulawesi, Buru, Misool and the Wombat Plateau (off NW Australia). The Triassic deposits are found in the parautochthonous, as well as in the allochthonous series of Seram; the facies of the two series are of Gondwanian–Australian type in the Parautochthonous and of Laurussian–Asian type in the Allochthonous. The Asinepe Limestone (=Manusela Formation), on which this study is based, has been considered as part of the allochthonous series. The Triassic reefal lithotypes can be divided into four main facies, as follows: (1) the boundstone facies forming the buildup cores; (2) the oncolitic grainstone-rudstone facies, indicating high energy conditions; (3) foraminiferal packstone-grainstone facies, characteristic of moderate to high energy conditions; and (4) the foraminiferal-megalodont mudstone facies, inferred to have accumulated in a quiet lagoonal environment. Forming the buildup cores of about 4 m long, 2 m high; they are separated by depressions filled with reef detrital sands; The Asinepe Limestone was deposited during the Late Triassic (Carnian–Norian to Rhaetian). This range is corroborated by foraminiferal and palynological data, and the coral framebuilders give evidence for a Norian–Rhaetian age. There is a some consensus that Seram and the Island of Buru, located west of Seram, belong to the same tectonic block (Seram-Buru Block). According to geochemical and geodynamic interpretations, the Seram-Buru Block is derived from Irian Jaya or from Papua New Guinea. The palynological results are consistent with reconstructions that place the Seram-Buru Block in a palaeogeographic zone distinct from that of Sulawesi, and therefore from the Kolonodale Block. For these reasons, it is here proposed that, during the Upper Triassic, the Seram-Buru Block and the Kolonodale Block were two separated entities, the former located in a more tropical position than the latter. In addition, the Seram palynological association shows a composite microflora of the warm Onslow and the cold Ipswich-types, suggesting that the Seram microcontinent moved progressively to the north and crossed the boundary between the temperate and the warm subequatorial belts at one point in the Late Triassic–Early Jurassic. | |
Keywords | Seram — Upper Triassic — Reefal carbonates — Foraminifers — Corals — Palynomorphs — Palaeobiogeography — Plate tectonics | |
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![]() ![]() Other version: http://linkinghub.elsevier.com/retrieve/pii/S0031018204000094 |
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Structures | ||
Research group | Sedimentology, Biostratigraphy and Micropaleontology | |
Citation (ISO format) | MARTINI, Rossana et al. Upper Triassic carbonate deposits of Seram (Indonesia): palaeogeographic and geodynamic implications. In: Palaeogeography Palaeoclimatology Palaeoecology, 2004, vol. 206, n° 1-2, p. 75-102. https://archive-ouverte.unige.ch/unige:4403 |