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AAPG Europe Regional Conference, Global Analogues of the Atlantic Margin

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Reconstruction of sedimentation in Maikop paleobasin in Azerbaijan

Abstract

The Maikopian Basin of Azerbaijan is a large Cenozoic depositional structure, which evolved in collision setting between the Greater Caucasus in the north, the Lesser Caucasus in the south, the Talysh in the southwest, and the South Caspian in the east (Fig. 1). This sedimentary basin is filled with thick packages of shales with coarser siliciclastic interbeds, which are known as the Maikop (also spelled as Majkop or Maykop) Group (often labelled in an "old-fashioned" manner as series). These deposits are famous by their lithological and geochemical peculiarities (e.g., Efendiyeva 2004; Hudson et al. 2008; Johnson et al. 2010; Efendiyeva et al. 2012), as well as by their hydrocarbon potential (Tawadros et al. 2006; Hudson et al. 2008). Moreover, the Maikop Group was accumulated when the Earth's climate and the global eustatic fluctuations changed significantly (Haq and Al-Qahtani 2005; Miller et al. 2005; Efendiyeva et al. 2008; Kominz et al. 2008; Zalasiewicz and Williams 2012); at the same time, the long-term collision started in the Caucasus (Ershov et al. 2003; Vincent et al. 2005; Tawadros et al. 2006). Thus, there was a puzzle of controls on the spatio-temporal development of the Maikopian Basin, which is yet to be fully understood. The formation of Maikop Group has been analysed in several paleobasins since Lower Oligocene (Rupelian) till Lower Miocene (Kotsahurian). Maikop formations belong to the early orogenic stage of development and by its structural-lithological features characterize the geodynamic regime of the Caucasian region. For the first time on the base of factual material maps of equal thickness for each stratigraphic unit of Maicop were compiled that allowed to determine the presence of a large amount of land area within which the rock of Maikop Group were not deposited at all. And if earlier it was believed that the Maikop deposits in the territory of Azerbaijan accumulated exclusively within the deep part of the paleo-basin, the present study indicated that the bulk of the Maikop paleobasin not exceed the limits of the shelf zone. It was not a deep as previously thought, but mostly shallow paleobasin, analogue of the modern Archipelago Sea, where in the straits between the islands there occurred the formation of sedimentary complex, composed mainly of fine-grained argillaceous rocks.