Significance Of Tectonics On Sedimentation In Actively Extending Sedimentary Basins In Cyprus Essay Example
The Easternmost Mediterranean to the east of Aegean located in a complex tectonic regime exists between the Arabian, African and Anatolian (Eurasian) plates with a collection of fragmented tectonic terrains including the island of Cyprus. Subduction, continent collision, obduction, rifting and transform faulting have been occurring along the plate margins since the early Mesozoic as a result of a collage of tectonic forces (Robertson, 1976, p. 1014). The boundary between the Anatolian and the African plates is represented by a deformation front commonly referred to as the ‘Cyprus Arc’ and located south of Cyprus between it and the Eratosthenes Seamount.
Tectonic influences on sedimentary basins have had a significant effect on the different mechanisms of sediment transport and deposition, facies distribution and stratal architectures in Cyprus. The Cyprus sedimentary basins are the areas whereby there have been sediments accumulations over a time period at a greater rate and to a significantly greater thickness compared to their surrounding areas (Robertson, 1976, p. 1014).
Tectonic forces that have generated basins in Cyprus have been the most significant prerequisite for sediment accumulation. The tectonic basin classification system classifies the Cyprian Basins as originating form tectonic influences. These Basins includes the Maroni-Psematismenos Basin, The Mesaoria Basin, The Polemi Basin and The Pissouri Basin. The three major basins are situated at the south of Troodos Massif. This basins includes the Pissouri Basin, the Polemi Basin and the Maroni-Psematismenos Basin. To the north of Troodos Massif is located a single basin called the Mesaoria Basin. Of all the four basin, each basin is somewhat filled to a certain level by non- marine sediments, Cretaceous to Quaternary marine.
Figure 1: The Tectonic map of the eastern Mediterranean (Zitter et al., 2003). The closed arrowheads have an indication of the crustal contraction areas. The open arrowheads indicate the subduction zones.
THE MARONI-PSEMATISMENOS BASIN
The Maroni-Psematismenos Basin has an area of ten kilometer north-south and 14 kilometer east-west. In the early Miocene, the Maroni-Psematismenos Basin was recognized as a depocentre that is tectonically driven. This was mainly in reference to the start of the Cyprus uplift. A number of discrete events of deformation and palaeogeographies that are distinct have been identified in the Maroni-Psematismenos Basin. The Maroni-Psematismenos Basin north margin is believed to be colonized by the koronia reefs (ROBERTSON, 2013, p. 605).
THE PISSOURI BASIN
The Pissouri Basin geographical located is 32º42’E, 34º40’N and is at the southwestern of Cyprus. The Pissouri Basin has an area of twelve kilometer north-south and 23 kilometer east-west. It is found between Evidhimou Bay that is to the east, Kouklia village that is to the west and Pano Archimandrita village that is to the north. The Pissouri Basin was formed during the time of tectonic instability in reference to Miocene phase of reorganization of palaeoenvironmental in relation to the start of Cyprus uplift. An integrated structure, magnetostratigraphic and sedimentological study of the Pissouri Basin provide an evidence of the late Holocene to Pliocene history of uplift of the Troodos Massif. The presence of Plio-Quaternary marine sedimentary rocks found in the Pissouri Basin provides a clear understanding of uplift and subsidence. The resent hypothesis explains that the formation of the Pissouri Basin was currently with the Polis Graben under the same extensional stresses. As a result of this, the rifting onset of the Pissouri Basin is thought to have started in the late Miocene. The recent analysis acquired from the Pissouri Basin show that both Pissouri Basin and Polis Graben may have formed contemporaneously. The resolved principal stress for the early Messinian to the late Tortonian structure in both Polis and Pissouri regions can be compared (STOKER, 1998 p. 357).
The crude clastinc objects fund in both Pissouri Basin and Mesaoria Basin has been related to the pluvial periods when the uplifting Troodos Massif erosion was very common. The thick deposits of palaeosol are believed to symbolize the period of interpluvial. The fluviate deposiote stacked are composed of units of gravel that are bedded rhymthically, deposits of floods, palaeosols is a sign of fluctuation of climate in the Mesaoria Basin. Furthermore climate change is also experienced by the presence of stack palaeosols and conglomerates in the Pissouri basin.
An extensional event of Messinian is evidenced in lago Mare deposition and Kalavasos Formation in the Pissouri Basin. More evidence of tectonism at the time of Messinian is identified in the Polis Graben. An evidence of local Karst formation and emergence at the time of Messinian was documented at the Polis Graben northern part.
THE POLEMI BASIN
The geographical location of Polemi Basin is 33°33’E, 35°00’N. This basin is situated inside the Polis Graben. Polemi Basin referrer top the basin created during the Messinian. The proposed model for the development of Polis Graben and the formation of Polemi Basin is largely based on the spatial and temporarily distribution of reefs in the West Cyprus. It is belived that a grate Basine used to exist in Polis Graben in the Aquitanian. These Basins were of high structure and were occupied by reefs recognized as Terra Member while the Basin was infilled partly with redeposited and hemipelagic carbonates of the formation of Pakhna. The palaeosols and the conglomerates are thought to be of same age as Messinian because of the lack of clasts that are Troodos- derived. Materials that are Troodos derived are comtained in the post Messinian deposits in Polemi. This can be concluded that the presence of the materials in Polemi Basin was controlled by Messinian. This is because messinian faulting determined material preservation and sediment supply within the Polemi Basin (GASS & PRICHARD, 1993 p. 116).
THE MESAORIA BASIN
The Mesaoria Basin is situated at the central of Cyprus. It is located between ophiolitic Troodos Massif that is at the south and the Kyrenia Range that is at the north. The basin is partly occupied by the sediments of Quaternary marines. These deposits includes limestones, evaporates, shallow marine deposits, Pleistocene .continental deposits (GEE & STEPHENSON,2006 p. 237).
According to the research, there were also two cycles of Messinian Evaporite sediments that were discovered before the earliest Miocene and Pliocene sediments that are all carbon-rich. These sediments represent the ‘Lago Mare’ facies within the Eastern Mediterranean as well as the Thyrrenian Basins. These were as a result of the tectonic induced transition from the initially restricted to open-marine conditions in the western Mediterranean (Menchu et al., 1996. p. 12)
The Easternmost Mediterranean had a relict of the Mesozoic oceanic crust however which remained in alarge embayment of the Mesozoic African continental margin allowed for the convergence to continue along the important regional tectonic lineaments (Ben-Avraham et al., 1995, p 267). The Cyprus Arc became the southernmost of these lineaments as the second runs through the Kyrenia Range in northern Cyprus.
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