Day 6, Locality 6

6) Potamos tou Ayiou Mina river, Choirokitia village; river section.

This section shows 8-10m of red-brown gravels and coarse conglomerates over white chalks, which appear brecciated in places. The slopes above the gravel beds are yellow to buff limestones. The white chalks at the base of the section are Miocene Pakhna Formation chalks and marls. Above the gravels are Miocene Koronia Member limestones, which form the upper unit of the Pakhna Formation. Inspection of the gravels shows grading of beds, with very coarse horizons with sharp bases fining upwards, and very fine horizons also developed. The clasts show a range of sizes and compositions. Koronia Member reefal limestones form a proportion of the angular blocks, together with white chalks of Pakhna origin. Dark igneous clasts are also seen in the gravels.

 The gravels are interpreted as Miocene-debrites, deposited in a submarine environment (Schirmer, 2000). Several individual debrite flows are recognised in the section, the coarser members being more proximal, the finer ones more distal. The igneous clasts can be identified as Troodos lithologies.  These beds are interpreted as gravity flows and submarine slumps off the uplifting Troodos oceanic crust. The presence of Koronia limestones as clasts indicate that Koronia limestone was already developed over the uplifting ocean floor, and the reefal nature of the Koronia sediments also indicates elevation of at least some parts of the ophiolitic crust and ocean sediments to shallower depth.

It is thought that as uplift occurred, early deposited Koronia limestone and lower pelagic chalks were stripped off the ophiolite by submarine erosion to reveal the igneous core. This then became the source of further debris as erosion continued. The debrites then flowed along submarine channels on the seabed, and in suitably shallower areas were overlain by more reefal carbonates. Several areas of these anastamosing channels have now been identified. We are thus looking at a fragment of Miocene sea floor topography.