Oligocene Cyclic Sedimentation Deduced from Taphonomic Analysis of Molluscs in Lacustrine Deposits of the Pematang Group, Pesada Well, Central Sumatra Basin

Aswan Aswan, Satia Graha, Dodi Suryadi, Taufan Wiguna, Sri Iman Qivayanti

Abstract


The Oligocene cycle of Pesada Well, Central Sumatra Basin, Indonesia is composed of a deepening-upward series of depositional cycles in a lacustrine environment affected by oscillations of the water level. Taphonomic analysis of gastropod molluscs was used to interpret the cycle architecture of the Brown Shale (Pematang Group). Four types of shell concentrations were identified. The early transgressive deposit has a distinct erosion surface at the base, contains concretions, is formed of coarse-grained sediment with abraded and broken shells, and is interpreted as reworked deposits. The late transgressive deposit contains a hiatal concentration formed by continuing lake level rise, with many complete shells preserved in life position. The maximum transgressive deposit has complete shells in life position or that have been transported, as well as juvenile molluscs and broken shells. The early regressive deposit contains alternating shell-rich and shell-poor layers. Since the lacustrine system shows no tectonic effects and also no marine influenced indications, the seven sedimentary cycles identified in the Pesada Well are likely to have been affected by oscillations between monsoonal and dry periods.

Keywords


dry period; lake; molluscs; monsoonal period; Pematang; Pesada; sedimentary cycles; taphonomy

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References


Heidrick, T. L. & Aulia, K., A Structural and Tectonic Model of The Coastal plains Block Central Sumatra Basin Indonesia, Proc. 22nd Ann. Conv. As. IPA, pp. 285-304, 1993.

Aditya, A.K.P., Aswan & Rizal, Y., Sequence Architecture Interpretation of Brown Shale (Pematang Group) Lacustrine Deposit based on Mollusk Taphonomic Analysis in Kiliranjao, West Sumatra, Proceedings Indonesian Geologist Association Annual Convention XXXVII, 2008.

Shipman, P., Life History of A Fossil: An Introduction to Taphonomy and Paleoecology, Harvard University Press., pp. 5-232, 1981

Aswan, Taphonomic significance and Sequence stratigraphy of The Lower Part of Nyalindung Formation (Middle Miocene), Sukabumi, Bulletin of the Department Geology–-Institut Teknologi Bandung, 38(3), pp. 131-144, 2007.

Wirbellose, T. & Zubehör, T., Mokka Tower Snail, Tom’s Garnelenshop, http://www.garnelen-tom.de/zwerggarnelen-shop/Riesen-Turmdeckelschnecke-Brotia-herculea, (1 March 2016). (Text in Germany)

Barrette, B., Banded Mysterysnail, Aquatic Biodiversity Monitoring Network, http://www.rsba.ca/recherche_espece/fiche_espece.php?record ID=516&lan=en, (1 March 2016).

Wilken, S., Fish: Prickly Tower Snail, Aqua4you, http:// www.aqua4you.de/fischart1199.html, (1 March 2016). (Text in Germany)

Aswan, Zaim, Y. & Rizal, Y., Distribution of Quarternary Freshwater Molluscs Fossils in Jawa, S. Sartono: Dari Hominid ke Delapsi dengan Kontroversi, Penerbit ITB, Yahdi Zaim, Yan Rizal, Aswan, Bayu Sapta Fitriana, pp. 109-120, 2006.

Aswan, Zaim, Y., Rizal, Y. & Prasetyo, U., Molluscan Evidence for Slow Subsidence in the Bobotsari Basin during the Plio-Pleistocene, and Implications for Petroleum Maturity, Journal of Mathematical and Fundamental Sciences, 47(2), pp. 167-184, 2015.

Posamentier, H.W., Jervey, M.T. & Vail, P.R., Eustatic Controls on Clastic Deposition I – Conceptual Framework, Sea-Level Changes – An Integrated Approach, Wilgus, C.K., Hastings, B.S., Kendall, C.G.St.C., Posamentier, H.W., Ross, C.A. & van Wagoner, J.C., Society of Economic Paleontologists and Mineralogists Special Publication, No. 42, pp. 125-154, 1988.

Van Wagoner, J.C., Posamentier, H.W., Mitchum, R.M., Vail, P.R., Sarg, J.F., Loutit, T.S. & Hardenbol, J., An Overview of Sequence Stratigraphy and Key Definitions, Sea Level Changes: An Integrated Approach, Wilgus, C.K., Hastings, B.S., Kendall, C.G.St.C., Posamentier, H.W., Ross, C.A. & van Wagoner, J.C., Special Publication-Society of Economic Paleontologists and Mineralogists, No. 42, pp. 39-45, 1988.

Parras, A. & Casadio, S., Taphonomy and sequence Stratigraphic Significance of Oyster-dominated Concentrations from the San Julian Formation, Oligocene of Patagonia, Argentina, Palaeogeography, Palaeoclimatology, Palaeoecology, 217(1), pp. 47-66, 2004.

Cantalamessa, G., Di Celma, C. & Ragaini, L., Sequence Stratigraphy Of The Punta Ballena Member Of The Jama Formation (Early Pleistocene, Ecuador): Insights from Integrated Sedimentologic, Taphonomic and Paleoecologic Analysis of Molluscan Shell Concentrations, Palaeogeography, Palaeoclimatology, Palaeoecology, 216(1), pp. 1-25, 2004.




DOI: http://dx.doi.org/10.5614%2Fj.math.fund.sci.2016.48.1.7

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