Neogene supra-subduction zone extension in the Polis graben system, west Cyprus

Abstract

The Neotectonic Polis graben and adjacent Pegia half-graben in west Cyprus are extensional basins developed within the convergent tectonic regime of the Eastern Mediterranean. Both basins contain an early fill of Miocene carbonates including reef limestones. Messinian extension, oriented ENE-WSW, produced the asymmetrically faulted Polis graben structure. Evaporites were deposited in the south of the area while unconformity surfaces developed in the north. Pliocene mark and chalks were then deposited in a relatively quiescent phase in the north of the graben, while faulting continued into the Early Pliocene in the south. Plio-Pleistocene to Recent sediments record regional uplift of Cyprus. Contemporaneous NNE-SSW-oriented extension formed the Pegia halfgraben and renewed minor faulting in the Polis graben.The extensional structures of the Polis graben system are thought to result from extension above a subduction zone located south of Cyprus, driven by subduction 'roll-back' and trench migration. Accelerated convergence and rapid roll-back during Late Miocene times caused the first stage of extension, whilst the Plio-Pleistocene faulting was driven by differential extension in the overriding plate as the Eratosthenes Seamount collided with the trench and locally impeded subduction. The Polis graben system may provide a model for the early stages of development of major suprasubduction zone extensional areas such as the Aegean region.

The Miocene–Pliocene boundary and the Messinian Salinity Crisis in the easternmost Mediterranean: Insights from the Hatay Graben (Southern Turkey)

“…Although, strontium data are lacking for this area, the stratigraphy is similar to that described for the Hatay Graben, indicating that the gypsums in the Nahir El-Kabi half-graben could belong to the RLG. Similar successions have been described for the Messinian evaporites in a number of sub-basins on Cyprus -the Polemi and Pissori sub-basins in the west and the Maroni sub-basin in the south (e.g., Eaton, 1987;Follows, 1992;Payne and Robertson, 1995;Robertson et al, 1995;Rouchy et al, 2001;Krijgsman et al, 2002;Manzi et al, 2015). In the western Polemi and Pissouri Basins, Tortonian marl successions reflect the progressive shallowing from ~ 500 m at Tortonian/Messinian boundary to < 100 m water depth and marine isolation leading up to the onset of evaporite deposition during the MSC (Kouwenhoven et al, 2006).…”

Quantitative dating of Pleistocene deposits of the Kyrenia Range, northern Cyprus: implications for timing, rates of uplift and driving mechanisms

“…In addition, the Hatay Graben is inferred to represent a transition from extension to transtension during the Miocene to Pleistocene, probably as a consequence of the regional westward tectonic escape of Anatolia (Boulton & Robertson 2008). Also, to the west of the Eratosthenes Seamount, crustal extension took place within the Polis Graben of western Cyprus, continuing into the Pleistocene (Payne & Robertson 1995). Such areas affected by Pleistocene extension are located well to the east or the west of the inferred roughly northsouth Eratosthenes-Troodos-Kyrenia collision zone.…”

The onset of the Messinian salinity crisis in the Eastern Mediterranean (Pissouri Basin, Cyprus)

“…1), which formed during a middle Miocene phase of palaeogeographic reorganisation [12,15^17]. This change in basin con¢guration re£ects tectonic instability related to both the uplift of the Troodos Massif [18] and the position of Cyprus in a fore-arc setting within the complex zone of convergence between Africa and Eurasia [16,19]. The Messinian evaporites were deposited in these sub-basins at a time when the African plate was undergoing northward subduction beneath Eurasia [17].…”