DETAILS OF DAY 6

The aim of the final day is to examine the sedimentation history of the island. In particular, the sediments that postdate the ophiolite will be examined to see what they can tell us about the later tectonic history of the ophiolite after the cessation of spreading, and how this relates to the tectonic evolution of this part of the Neotethyan ocean. We will also gain evidence that allows us to chart the development of the eastern Mediterranean. The day will be spent examining sections to the east of Limassol.

 As supra-subduction zone spreading and crustal accretion proceeded during the Cenomanian-Turonian to give the Troodos (and others) ophiolite the northward progression of the African and Arabian Plates brought the Arabian platform to the convergence. The promontory of the Arabian platform is thought to have collided with the eastern end of the subduction zone causing tectonic disruption to the nearby neo-oceanic crust. Whilst the Troodos region was west of the collision zone the collision effectively terminated spreading of the Troodos ridge. More importantly it detached the Troodos segment of oceanic crust as a microplate fragment, and rotated it anticlockwise through 90 degrees over the next 35 million years. During this rotation the Mamonia lithologies were interleaved and juxtaposed with the Troodos crust.

 These events took place with the Troodos crust at bathylal depths, around 4 km deep. Once spreading and oceanic crustal accretion had ceased, the ocean floor received pelagic sedimentation in the form of carbonate ooze above the hydrothermally derived umbers, radiolarites, and sedimented muds of the Perapedhi and Kannaviou Formations. In tectonically active areas fault breccias and turbidite flows were generated as local facies, and form the Moni and Kathikas Formations. Pelagic sedimentation continued until the Miocene, during which time several hundred metres of mainly chalks, with cherts, the Lefkara Formation, were accumulated.

 During the Early Miocene the African/Eurasian convergence zone, which had shifted away from the Cyprus area, now became active again south of the Cyprus region, and northward subduction was reactivated. Underthrusting of continental crust under the Cyprus microplate began a phase of uplift, which was episodic in nature. From this time onwards the sedimentary record shows the progressive coarsening of the marine sediments, biostrome development, and ultimately coarse terrigenous clastics as the Troodos area became emergent. The Miocene Pakhna chalks, Kalavassos evaporites, and Nicosia Formation Pliocene clastics and marls all indicate shallowing. In the Pleistocene, serpentinite diapirism and underthrusting of a major fragment of continental crust, possibly part of the Eratosthenes seamount created a major uplift centred on the Troodos Mt. Olympus area, and Cyprus emerged from Tethys as an island. The Fanglomerates, which overlie the Nicosia Formation unconformably, and comprised of terrigenous clastics are evidence of this uplift.

 During the time from the cessation of spreading in the Turonian, the Neotethyan Ocean basin had been closing and shrinking, and fragmenting into smaller sub-basins. Parts of the ocean floor became uplifted to shallow depths, whilst some parts, for example Cyprus, became land. The present day bathymetry of the eastern Mediterranean reflects these developments, and the tectonic elements that evolved still govern the geological development of the eastern Mediterranean today. The Eratosthenes seamount is still in collision with the Cyprus Arc, and the episodic subduction is reflected in seismic activity, raised beaches, deeply incised river valleys, and river terraces.