Article
Reference
Upper Triassic Shallow Water Limestones in the Sinta Ridge (Banda Sea- Indonesia)
VILLENEUVE, M., et al.
Abstract
Ten rock samples were dredged during the Banda Sea I cruise in the northern slope of the Sinta Ridge, which separates the North and South Banda basins. Some of the samples are limestones from a very shallow marine environment, with Upper Norian (to Rhaetian?) benthic Foraminifera. Similarities with eastern Sulawesi, Buru and Seram are consistent with an independant Upper Triassic block and the origin of the Banda Sea microcontinents is questionable.
VILLENEUVE, M., et al . Upper Triassic Shallow Water Limestones in the Sinta Ridge (Banda Sea- Indonesia). Geo-Marine Letters , 1994, vol. 14, no. 1, p. 29-35
DOI : 10.1007/BF01204468
Available at:
http://archive-ouverte.unige.ch/unige:9830
Disclaimer: layout of this document may differ from the published version.
1 / 1
M. Villeneuve . J.-J. Cornee . R. Martini . L. Zaninetti J.-P. Rehault . S. Burhanudin . J. Malod
Upper Triasslc shaUow water Umestones in the Sinta Ridge (Banda Sea, Indonesia)
Received: 7 June 1993 / Revision received: 28 September 1993
Abstract Ten rock samples were dredged during the Banda Sea 1 cruise in the northern slope of the Sinta Ridge, which separates the North and South Banda basins.
Sorne of the samples are limestones from a very shallow marine environment, with Upper Norian (to Rhaetian?) benthic Foraminifera. Similarities with eastern Sulawesi, Buru and Seram are consistent with an independant Upper Triassic block and the origin of the Banda Sea micro- continents is questionable.
Introduction
During the Banda Sea 1 cruise on board of Baruna Jaya III (July-August 1992), several rock samples were dredged along the northern edge of the Sinta Ridge between 3600- and 3900-m water depth. The Sinta Ridge is located in the southeastern North Banda (or Bajo) basin (Fig. 1). The North Banda basin is separated from the South Banda basin by both the Sinta and Tukang Besi ridges (also called the Banda ridges) which are at 2000- to 3000-m depth.
On the other sides the North Banda basin is surrounded by several islands of continental origin, among them:
Sulawesi, Banggai, Sula, and Buru. The eastern Sulawesi margin is thrusted over the Banda basins and blocks as is,
M. Villeneuve
CNRS, Institut de Géodynamique, URA 1279, Av. Albert Einstein, Sophia Antipolis l, 06560 Valbonne, France
J.-1. Cornee
CNRS, URA 1208 "Dynamique des pates-formes carbonatées,"
Université de Provence, 13331 Marseille Cedex 03, France R. Martini . L. Zaninetti
Université de Genève, Département de Géologie et de Paléontologie, 13, rue des Maraîchers, CH-1211 Geneva, 4, Switzerland
J.-P. Rehault . S. Burhanudin
CNRS, URA 1278, U.B.O, 6, avenue Le Gorgeu, 29275 Brest Cedex, France
J. Malod
CNRS, GEMCO, URA 718, UPMC, 4, pl. Jussieu, 75252 Paris Cedex 06, France
for example, the Buton thrust, which separates the south- eastern Sulawesi and the Tukang Besi ridge. These thrusts are linked to the Miocene to Pliocene collisions (Fortuin et al. 1990) on the eastern Sulawesi margin. Elsewhere, contacts between blocks and basins are normal or strike slip faults.
The origin of the Banda Sea is still disputed. It is consid- ered to be a trapped Mesozoic lithosphere piece of Indian Ocean affinities; (Pi gram and Panggabean 1984; Karta 1985; Lapouille et al. 1985; Lee and McCabe 1986).
According to Hamilton (1979), Silver et al. (1985), and Charlton (1986), it should be a Neogene basin similar to the Sulu basin. Nishimura and Suparka (1990) favored a mid-Pliocene backarc origin for the South Banda basin.
On other hand, Rehault et al. (in press) favor a mid to late Miocene basin with an oceanic crust created 9-7 Ma ago on the basis of new geochronological data from dredged sites SB1 and SBU2 (Fig. 1).
From the Tukang Besi and Sinta Ridge were previously collected diamictites, diabase, cherts, slates, calcarenites, foraminiferal oozes, and laminated calc-siltstones on the first ridge (Silver et al. 1985). South of the Sinta Ridge, on the Lucipara Ridge, Silver et al. collected continental clas- tic sedimentary and metamorphic rocks including lithic breccias, graywackes, slates, and quartzites attributed to the Lower Paleozoic, although a whole-rock K-Ar da- tation yielded an age of 22.5 Ma for a phyllite and 10.8 for an amphibolite. From the assignment ofthese rocks, Silver et al. (1985) proposed a continental origin for aIl Banda Considering the eastern Indonesian domain as the re- suIt of the convergence of three major plates (Australian, Eurasian, and Philippines Sea plates), the evidence of Up- per Triassic limestones along the Banda ridges pro vides fundamental information for geodynamic reconstructions.
Site BS 101B is located on the northern slope of the western Sinta Ridge (Fig. 1), on seismic line BS 39 (Fig. 2), at
30
1240 E E
1
DANGGAI-SULA
S F Z Sula Fracture Zone WB F Z West Buru Fracture Zone HFZ Hamilton Fracture Zone
NNW
DR 101 B
B T Batui Thrust
BuT Buton Thrust
Dredged location Fracture Zone ThrustZone Seismic profile
Fig. l Main structural elements of the North Banda Sea anld conti- nental margins with location of the DR 101 B dredging
SSW
Sinta Ridge
3000In---4---~=
North Banda Basin
375()-~---~~
Fig. 2 Location of the dredged site DR 101 B on the BS 39 seismic profile
3900-3600 m deep. The seismic li ne reveals the existence of a thin sedimentary cover (about 500 m) on the top of ridges. Siliciclastic rocks and carbonate sediments were , dredged up:
Clastic sediments: The clastic sediments were not dated.
There are grey shales (101 B-6, 100 B-ll), grey to black slightly schistozed siltstones (101 B-lO), sand stones with micas (chlorite, muscovite, and biotite), and microcon- glomerates with well-rounded millimeter-sized grains of quartz and green clay (101 B-7);
Carbonate sediments: Five different carbonate facies were collected: oolitic grainstones (101 B-1), bioclastic grainstones (101 B-2), bioclastic grainstones to packstones (101 B-3), mudstones/wakestones (101 B-4), and peloidal packstones to wackestones (101 B-5). Samples 101 B-1, B-2, B-3, and B-5 are from shallow water carbonate platform environment; sample 101 B-4 is quite different, consisting of pelagic limestones including planktonic F oraminifera.
No fossils were found in the siliciclastic sediments but the carbonate rocks contain microfauna.
Sample 101 B-2: An oligotypical foraminiferal associa- tion is composed of numerous Aulotortus ex gr. sinuosus Weynschenk (1956) (Fig. 3: 1-6,9-10). One Triasina ober- hauseri Koehn-Zaninetti & Bronnimann (1968) (Fig. 4: 1), and sorne Duostominidae (Fig. 3: 7) have been identi- fied in this sample. Bioclasts from dasycladal algae, echinoids (Fig. 3: 8, and corals are associated with the Foraminifera. Triasina oberhauseri was found in the Tethysian domain: northern Autrichian Alps (Koehn- Zaninetti and Bronnimann 1968), western Carpathian (Salaj et al. 1988) (Duostominidae, Fig. 4: 5B), Carpato- Balkanic domain (Salaj et al. 1988), Panormid platform (Abate et al. 1984), western Taurus (Bronnimann et al.
1970), Wombat Plateau (NW Australia, offshore) (Rohl et al. 1991; Zaninetti et al. 1992) and in other places (Abate et al. 1984). The association of Triasina oberhauseri, Aulo- tortus ex gr. sinuosus and Duostominidae is Upper Norian (to Raethian?) in age.
Sample 101 B-5: This sample contains sorne benthic Foraminifera, gastropods, ostracods, and fragments of echinoids and dasycladal algae. Foraminifera are essen- tially Aulotortus sp. (Fig. 4: 2-5A), Duostominidae (Fig. 4:
5-7), Miliolidae (Quinqueloculina? sp., Fig. 4: 8, 9) and Nodosariidae. The presence of large size Duostominidae and Aulotortus in the same sample indicates an Upper Triassic age (Norian?).
Samples 101 B-l and 101 B-3: Samples contain sorne benthic Foraminifera, gastropods, and fragments of bi- valves. Foraminifera seem to be Textulariidae (?) from Middle Triassic to Jurassic age.
Sample 101 B-4: Planktonic Foraminifera are weIl sorted and small in size, embedded into a micritic matrix including sorne detrital grains and sorne soft pebbles. The
facies indicates that the Foraminifera were probably re- worked from their depositional area. As the shells suffered recrystallization, the determination is not possible. From the shape of the sheIls, the Foraminifera could indicate ages ranging from Cretaceous to Oligocene (G. Glaçon 1993 personal communication).
The siliciclastic rocks remain undated. The carbonate rocks clearly in di ca te the existence of Upper Triassic (at least in samples 101 B-2 and 101 B-5) and Cretaceous (?) to Oligocene (?) age. The Upper Triassic rocks indicate a very shallow water environment (corals in sample 101-B-2, dasycladal algae). That strongly supports the Silver et al.
(1985) hypothesis about the continental origin of the Banda ridges. The thin sedimentary co ver on the Banda ridges likely fits with the middle to late Miocene deposits as was reported by Silver et al. (1985) from the Tukang Besi Ridge. The drowning of the Sinta Ridge began after the Upper Triassic and before the Cretaceous-Oligocene pelagic deposits of sample 101 B-4, as a consequence of the collapse of the Banda ridges.
Silver et al. (1985) correlated the sedimentary and meta- morphic rocks from the Banda ridges to those of the Irian Jaya Paleozoic basement but no Triassic carbonate plat- form has yet been documented from that area. According to Dolan and Hermany (1988), Triassic and Jurassic de- posits comprise mainly continental sandstones and silty mudstones in the Bird's Head area. On the other hand, the Upper Triassic rocks are subaerial volcanics in the Banggai-Sula archipelago (Garrard et al. 1988) and basinal sediments in Buton (Smith and Silver 1990) and Timor (Harsomalukso 1993). However, according to Pi gram and Panggabean (1984), a Norian to Rhaetian carbonate plat- form was documented in several islands surrounding the Banda Sea (Fig. 5): Buru, Seram, and Misool. Moreover, such a carbonate platform of 200-m thickness was recently evidenced in the eastern arm of Sulawesi (Kolonodale area), with a Rhaetian age (Cornée, Martini, Villeneuve, Vachard, and Zaninetti, 1991 and 1992, personal observa- tion). AlI these continental blocks, including the Banda ridges, appear to be fragments of a single Upper Triassic block separated from the Timor and Irian Jaya blocks, as suspected by Daly et al. (1987).
The Upper Triassic (Norian-Rhaetian?) lime stone plat- form of the Sinta Ridge exhibits a back-reef lagoon facies, ri ch in Foraminifera (Aulotortidae) and dasycladal algae;
the Norian marker Triasina oberhauseri is also present.
Similar benthic Foraminifera associations are known in many Upper Triassic reefformations of the European and
32
8 9
3
500 Il
10
Fig. 3 1-6, 9, 10: Aulotortus ex gr. sinuosus Weynschenk (1956) (101 8-2). 7: Duostominidae (101 8-2). 8: Grainstone with benthic Foraminifera and dasyc1adal algae (101 8-2)
r
8 9 10
Fig.41: Triasina oberhauseri Koehn-Zaninetti & Bronnimann (1968) (101 B-2). 2-4, 5A: Aulotortus sp. (101 B-5). 5B-7: Duostominidae (101 B-5). 8, 9: Quinqueloculina sp. (101 B-5). 10: Packstone with benthic Foraminifera and pellets (101 B-5)
34
Fig. 5 Location of the Upper Triassic carbonate platform outcrops in eastern Indonesia
* Upper Triassic carbonate ~ Subduction zon platform
Asian Tethysian realm. Among the closest Triassic local- ities of the Sinta Ridge, Seram Island (Outer Banda Arc, Anisepe limestones) (AI-Shaibani et al. 1983) and the Wombat Plateau (northwestern Australia, ODP Leg 122) (Zaninetti et al. 1992) also show reefal series. These series con tains microfauna comparable to those from the Banda Sea; however, in the Banda Sea samples, the Rhaetian marker Triasina hantkeni and the very typical forms of Galeanellas are absent. On the other hand, in the Sinta Ridge the presence of Triasina oberhauseri indicates the existence of an older platform (Norian-Upper Norian?).
Discovery of the Upper Triassic fossiliferous carbonate platform facies dredged onto the northern edge of the Sinta Ridge supports the Silver et al. (1985) hypothesis about the continental origin of the Banda ridges. However, the Up- per Triassic facies similarities are not consistent with Irian Jaya but with Buru, Seram, and eastern Sulawesi. This supports the existence of an isolated Upper Triassic Banda block presently splintered into several continental micro- blocks, as is suggested by Daly et al. (1987). The sliver plate origin of the Banda Sea blocks is so questionable. The ages of the pelagie facies dredged in the same area are not precise enough to date the beginning of the drowning of
the Upper Triassic platform, which could not occur after the Oligocene.
References
Abate B, Ciarapica G, and Zaninetti L (1984) Triasina oberhauseri Khoen-Zaninetti et Bronnimann, 1968, dans le Trias supérieur récifal (faciès "back-reef") de la Plate-forme Panormide, Sicile.
Revue de Paléobiologie 3(1): 19-25
Al-Shaibani S, Carter DJ, and Zaninetti L (1983) Geological and micropaleontological investigations in Upper Triassic (Anisepe Limestones) of Seram, Outer Banda Arc, Indonesia. Archives des Sciences de Genève 36:297-313
Bronnimann P, Poisson A, and Zaninetti L (1970) L'Unité du Domuz Dag (Taurus Lycien-Turquie). Microfaciès et Foraminifères du Trias et du Lias. Rivista Italiana di Paleontologia 76: 1-36 Charlton TR (1986) A plate tectonic model for the eastern lndonesia
collision zone. Nature 319: 394-396
Daly MC, Hooper BGD, and Smith DG (1987) Tertiary plate tec- tonics and basin evolution in Indonesia. Proceedings of the lndo- nesian Petroleum Association, 16th Annual Convention, Jakarta pp 399-428
Dolan P J and Hermany (1988) The geology of Wiriagan field, Bintuni Basin, Irian Jaya. Proceedings of the Indonesian Petroleum Asso- ciation, 17th Annual Convention, Jakarta pp 53-69
Fortuin AR, De Smet MEM, Hadiwastra S, Van Marle Ll, Troelstra SR, and Tjokrosapoetro S (1990) Late Cenozoic sedimentary and tectonic history of south Buton, Indonesia. Journal of Southeast Asian Earth Sciences 4: 107-124
Garrard RA, Supandjuno JB, and Surono (1988) The geology of the Indonesian Petroleum Association, 17th Annual Convention, Jakarta pp 23-52
Hamilton W (1979) Tectonics of the Indonesian region. Professional Paper of the United States Geological Survey 1078 345 pp Harsolumakso AH (1993) Etude lithostratigraphique et structurale le
long du transect Wini-Kolbano, à Timor ouest (Indonésie). Thèse de l'Université de Nice-Sophia Antipolis (F) 259 pp
Karta K (1985) Etude géodynamique de la mer de Banda (Indonésie) par interprétation des données magnétiques et gravimétriques.
Thèse de Doctorat d'Ingénieur de l'Université de Bretagne Occi- dentale (F) 177 pp
Koehn-Zaninetti Land Bronnimann P (1968) Triasina oberhauseri, n. sp., un foraminifère de la Dolomie principale des Alpes cal- caires septentrionales (Autriche). Publication de l'Institut de Paléontologie de l'Université de Genève (CH) pp 1-8
Lapouille A, Haryono H, Larue M, Pramumijoyo S, and Lardy M (1985) Age and origin of the seafloor of the Banda sea (eastern lndonesia). Oceanologica Acta 8: 379-389
Lee CS and McCabe R (1986) The Banda-Celebes-Sulu basin: A trapped piece of Cretaceous-Eocene oceanic crust? Nature 322:
51-54
Nishimura Sand Suparka S (1990) Tectonics of east lndonesia.
Tectonophysics 181 :257-266
Pigram CJ and Panggabean H (1984) Rifting of the continental margin of the Australian continent and the origin of sorne micro- continents in eastern lndonesia. Tectonophysics 107:331-353 Rehault JP, Maury R, Bellon H, Sarmili L, Malod JA, Burhonuddin
S. (in press). Discovery of a young oceanic crust within the North Bauda Sea (East lndonesia): a recent back-arc basin? 10th Anni- versary of lndonesia-France joint cooperation on ocean Technol- ogy (1992), Spec. issue, Jakarta (lndonesia)
Rêihl U, Dumont T, von Rad U, Martini R, and Zaninetti L (1991) Upper Triassic Tethyan Carbonates off Northwest Australia (Wombat plateau, ODP Leg 1221). Facies 25: 211-252 Salaj J, Trifonova E, and Gheorgian D (1988) Biostratigraphic zona-
tion based on benthic foraminifera in the Triassic deposits of the Carpatho-Balkans. Revue de Paléobiologie, Genève (CH), vol.
spéc. 2. Benthos 1986: 153-159
Silver EA, Gill JB, Schwarz D, Prasetyo H, and Duncan R (1985) Evidence for a submerged and displaced borderland, north Banda Sea, lndonesia. Geology 13: 687-691
Smith RB and Silver EA (1990) Geology of a Miocene collision complex, Buton, eastern Indonesia. Geological Society of Amer- ica Bulletin 103: 660-678
Zaninetti L, Martini R, and Dumont T (1992) Triassic foraminifera from sites 761 and 764, Wombat Plateau, northwestern Australia.
In: von Rad U, Haq BU, et al. (Eds.), Proceedings ODP, Scientific results 122 pp 427-436
