SEDIMENTOLOGY OF 2 FAN-DELTA SYSTEMS IN THE PLIOCENE-PLEISTOCENE OF THE MESAORIA BASIN, CYPRUS

Two fan-delta systems have been recognised in the Pliocene-Pleistocene deposits of the Mesaoria Basin, an asymmetrical half-graben located o n the northern side of the Troodos ophiolite, Cyprus. The older fan-de lta system, the Pliocene Nicosia Formation, was deposited when the Mes aoria Basin was actively subsiding. It comprises a number of small, is olated fan deltas which built across a narrow (< 5 km), steep, fault-c ontrolled, largely submerged basin margin. The preserved marine facies of this fan-delta system are confined to channels cut into the basin margin, and are dominated by marine conglomeratic, mass-flow deposits. In contrast, the much thinner (< 20 m), younger (Late Pliocene-Pleist ocene) fan-delta system of the Kakkaristra Formation was deposited whe n basin subsidence had virtually ceased and the Mesaoria seaway had fi lled to become a shallow, sandy platform. This renewed fan-delta sedim entation was initiated by uplift of the Troodos ophiolitic massif. In response to uplift, alluvial systems built northwards and coalesced at the coastline, giving rise to a large shelf fan delta that prograded into the basin. Conglomeratic sediments were largely trapped in subaer ial and coastal areas, and were deposited by both mass-flow and tracti on-current processes. In addition, some gravel was redistributed along the shoreline by wave action. Coastal fan-delta deposition was termin ated by renewed uplift of the Troodos Massif, initiating deposition of the Pleistocene fanglomerate unit.