INDONESIAN JOURNAL on GEOSCIENCE Tertiary Sequence Stratigraphy of Bird Head Area, Eastern Indonesia
Total Page:16
File Type:pdf, Size:1020Kb
Indonesian Journal on Geoscience Vol. 6 No. 3 December 2019: 267-278 INDONESIAN JOURNAL ON GEOSCIENCE Geological Agency Ministry of Energy and Mineral Resources Journal homepage: hp://ijog.geologi.esdm.go.id ISSN 2355-9314, e-ISSN 2355-9306 Tertiary Sequence Stratigraphy of Bird Head Area, Eastern Indonesia Syaiful Alam and Djadjang J. Setiadi Faculty of Geological Engineering, Universitas Padjadjaran Jln. Raya Bandung-Sumedang Km.21 Jatinangor, Indonesia 45363 Corresponding author: [email protected] Manuscript received: November, 8, 2016; revised: July, 6, 2017; approved: May, 8, 2019; available online: November, 5, 2019 Abstract - A long depositional period of Papua limestone called Kais Formation, which is overlain by clastic sediments of Steenkool Formation, reflects an interesting stratigraphic architecture in the West Papua region. Using seismic stratigraphic method of five stacking patterns, forestepping, downstepping, upstepping, backstepping, and seismic facies (parallel, prograding clinoform, channel fill, mounded) have been observed. Chronostratigraphic reconstruction was completed to figure out the depositional units in space and time. This study reveals the lowstand deposit during Early to Middle Eocene (LST), transgressive-highstand carbonate deposit during Middle Eocene to Middle Oligocene, and transgressive-highstand silisiclastic (TST-HST) deposit during Middle Miocene - Late Pliocene. Keywords: sequence stratigraphy, chronostratigraphy, Tertiary, West Papua, Kais Formation © IJOG - 2019. All right reserved How to cite this article: Alam, S. and Setiadi, D.J., 2019. Tertiary Sequence Stratigraphy of Bird Head Area, Eastern Indonesia. Indo nesian Journal on Geoscience, 6 (3), p.267-278. DOI: 10.17014/ijog.6.3.267-278 Introduction mic figure, this stratal clinoform is in association with drowning unconformity. In the eastern Bird There are a number of sedimentary basins Head region of West Papua, Indonesia, Middle around the Bird Head area of Papua Island, in- Miocene strata record a drowning unconformity cluding Salawati and Bintuni Basins which are and their related strata are important records of hydrocarbon-producing basins. Kasuri, Jamusura, key tectonic and environmental events throughout Besiri River, and Monie are the dry wells that the earth history (Gold et al., 2017). Strata that had been abandoned in West Papua (Tobing and may represent drowning successions have been Robinson, 1990). IJOGdescribed previously in the Bird Head, but were Those wells are located around Bintuni Bay. not recognized as such (Visser and Hermes, 1962; The Bintuni Bay is an area that has some gas- Pieters et al., 1983; Gibson and Soedirdja, 1986; producing wells. Although the Bintuni Bay has a Brash et al., 1991; McAdoo and Haebig, 2000). structural trap, there is a possibility for exploring The stratigraphic clinoform plays a significant stratigraphic trap by discovering stratal clinoform role in the study of sequence stratigraphy as the geometry in the southern Bintuni Bay. In a seis- key to some progradational and retrogradational Accredited by: RISTEKDIKTI (1st grade), valid August 2016 - April 2020 Indexed by: SCOPUS (Q3) 267 Indonesian Journal on Geoscience, Vol. 6 No. 3 December 2019: 267-278 pattern. It is important to consider that clinoforms region is bounded by Lengguru Fold-Thrust Belt in seismic data are depositional forms with di- (LFTB), the northern part is bounded by the oldest mensions varying from few hundreds of meters rock of Kemum Block, the western part is bounded to several kilometers (Berton and Fernando, by Misool-Onin-Kumawa (MOKA) Structural 2016). This research aims to find answers to High, and the southern part is bounded by Tarera- these problems, which is seeking the status of the Aiduna Fault, then also a strike-slip fault called clinoform through stratigraphic sequence analysis Sorong Ransiki Yapen (Gold et al., 2017; Fraser in the discovery of Tertiary play. Several issues et al., 1993). Pieters et al. (1983) has divided the remain to be addressed by clinoform involving Bird Head stratigraphy into Pre-Carboniferous the influence of paleotopography of the clinothem Basement, Permian Sediments, Triassic-Jurrasic on deposition, as well as paleorelief between the Sediments, Cretaceous Sediments, New Guinea clinoform inflection and paleodepth (Miller et Limestone Group, and Late Cenozoic Clastic al., 2013). Sediments. Mesozoic series consist of terrigenous shaly material at the base. The Tertiary lithologies are Geological Setting dominated by thick Eocene to Miocene New Guinea Limestone, overlain by Middle Miocene The geological setting of West Papua is tectoni- to present, fine-grained turbidites, and Molasse cally complex, according to Pieters et al. (1983), deposits. However, Paleocene gravity flow sedi- Chevallier and Bordenave (1986), and Perkins and ments do not cropped out in the surface. Three Livsey (1993). The eastern part of the West Papua major sequences from older to younger are: IJOG Figure 1. Geological map of West Papua region, modified from Atmawinata and Ratman, 1989; Atmawinata et al., 1989; Hartono et al., 1989; Sukanta and Pigram, 1989; Ratman et al., 1989; Amri et al., 1990; Supraman and Robinson, 1990; Tobing et al., 19990; Tobing and Robinson, 1990). 268 Tertiary Sequence Stratigraphyof Bird Head Area, Eastern Indonesia (S. Alam and D.J. Setiadi) - The Lower Tertiary group of New Guinea stratigraphy, especially on the stratigraphic sur- Limestone is as the main part of Lengguru face boundaries. Thrust Belt. Older rock formation underlain the studied - Pliocene Steenkool Formation covers most interval, Paleocene, is composed of sand-shale of southern part of the Bird Head region alternations overlain by evaporitic facies, chang- (Bailly et al., 2009). ing laterally to shaly carbonates. Starting from - The post sequence (11 Myr) shows two Eocene to Early Miocene, Faumai, Sirga, and clastic formations which are synchronous Sago Formations comprise of light brown, often to the LFTB. dolomitic, limestone, and crystalline dolomite in Reef buildups were common in the Lower a carbonate platform. An unconformity between and Middle Miocene on paleohighs, including Miocene limestones of Kais Formation with previ- long-lived basement highs (Bailey et al., 2015). ous limestone formation is to be early formation of There are several different published models of Bintuni Basin. The lithology of younger formations the origin of the Bird Head region. It is clear is composed of alternating shale and sandstone, that deformation of the region varies from area with conglomeratic sandstones and claystones. to area indicating that the region experienced Analysis and interpretation of this research in- several translations and rotations during their tegrate the seismic data and biostratigraphy that history (Sapiie et al., 2012). Understanding yield different conclusions from previous studies. the stratigraphy in the area is critical in solv- ing Tertiary play of the Bird Head region, in addition to an understanding the complexity in Material and Method structural trap and another trapping style. Fig- ure 2 is a regional stratigraphy that in further To accomplish these objectives, this study explanation on stratigraphy (evaporitic to shaly follows the procedure of seismic sequence, carbonate) implies the presence of Paleocene to seismic facies, and chronostratigraphy analyses Middle Miocene rock and corresponds to lateral (Figure 3). Those procedures are made to be more variation. The regional stratigraphy above is objective. The data used in this study include developed using lithostratigraphy that would be different emphasis from the concept of sequence Data Age Biostratigraphy Well-log 2D Seismic Regional Legend (Million years) Formation Lithology Setting Reg 0 Trans Pleistocene Sele Well-based Shale Steenkool Stratigraphic Pliocene Sandstone Surface L Klasafet/ Conglomerate Miocene Kais M Seismic Sequence Coal Well Correlation & Facies E Sago Limestone Depositional Sequence Oligocene Sirga IJOGDolomite Faumai Evaporite Eocene Systems Tracts Chronostratigraphy Waripi Paleocene Depositional History Figure 2. Stratigraphy of West Papua (Chevallier and Bordenave, 1986). Figure 3. Research workflow. 269 Indonesian Journal on Geoscience, Vol. 6 No. 3 December 2019: 267-278 moslty onshore seismic line, gamma-ray log, e Lithology: nc t c and biostratigraphy. The seismic data are used a Shale r l l T a y bunda a Gamma-ray r s A or or t Sandstone m t l l for analyzing seismic stratigraphy and facies t Log t e i a a i t r Stratigraphic s e or y ounda f Dolomite t ubl ubl t l S l i Surface B S / a ni S l geometry. The existing biostratigraphic analysis a t i r a r e hy or Limestone ni m t t t a a ut U i upr nne B or L I S by Atlantic Richfield and Horizon is to obtain age Marls O 0 GAPI 200 F rock formations and paleobathymetry. The depositional sequences have two prop- BSFR/SB2 erties which make them ideal for interpretation Unit 4 ne e HST on seismic data. First, they may be defined ob- MFS oc i l jectively using termination of reflections along P surface of discontinuities, interpreted as stratal Unit 3 terminations along unconformable sequences TST boundaries. The second, deposition of most major sequences appears related to global changes of ne CC/SOS e oc sea level (Mitchum and Vail, 1977). i M Seismic sequence analysis aims to determine Unit 2B/ surface discontinuities of seismic termination as a HST ne result of gap time, due to erosion or nondeposition. e oc g i Seismic facies analysis