Ecological succession, palaeoenvironmental change, and depositional sequences of Barremian–Aptian shallow-water carbonates in northern Oman

Authors

  • Bernard Pittet,

    1. Institut Français du Pétrole, 92506 Rueil-Malmaison Cedex, France
    2. (E-mail: bernard.pittet@univ-lyon1.fr)
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    • Present addresses: 1Université Claude Bernard Lyon 1, UFR des Sciences de la Terre, La Doua, F-69622, Villeurbanne Cedex, France.

  • Frans S. P. Van Buchem,

    1. Institut Français du Pétrole, 92506 Rueil-Malmaison Cedex, France
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  • Heiko Hillgärtner,

    1. Institut Français du Pétrole, 92506 Rueil-Malmaison Cedex, France
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    • 2Free University, De Boelelaan 1105, 1081 HV Amsterdam, The Netherlands.

  • Philippe Razin,

    1. Centre EGID, Bordeaux University III, F-33407, Pessac Cedex, France
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  • Jürgen Grötsch,

    1. Abu Dhabi Company for Onshore Operations (ADCO), PO Box 270, Abu Dhabi, UAE
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    • 3Shell Gas Abu Dhabi BV, PO Box 46807, Abu Dhabi.

  • Henk Droste

    1. Petroleum Development Oman (PDO), PO Box 81, 113 Muscat, Sultanate of Oman
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    • 4Carbonate Research Center, Sultan Qaboos University, Muscat, Sultanate of Oman.


Abstract

Abstract Barremian and Aptian shallow-water carbonate facies (uppermost Lekhwair, Kharaib and Shuaiba Formations) are described from outcrops in northern Oman. Based on facies analysis and bedding pattern, three orders of depositional sequences are defined (third to fifth order) and correlated between sections. Over the course of three third-order sequences, covering the Barremian to Lower Aptian, a third-order depositional pattern is documented that consists of a succession of three distinct faunal assemblages: discoidal orbitolinids and calcareous algae were deposited during early transgression; microbialites and microencrusters dominate the late transgressive to early highstand facies; and a rudist- and miliolid-dominated facies is typical of the highstand. This ecological succession was controlled largely by palaeoenvironmental changes, such as trophic level and clay influx, rather than sedimentological factors controlled by variations in accommodation space. Orbitolinid beds and carbonates formed by microbialites and microencrusters seem to be the shallow-water carbonate response to global changes affecting Late Barremian to Aptian palaeoclimate and palaeoceanography.

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