Pleistocene geomorphological and sedimentary development of the Akaki River catchment (northeastern Troodos Massif) in relation to tectonic uplift versus climatic change

The uplift of the Troodos ophiolite is reflected in the development of the Akaki River catchment in the northeast Troodos Massif. Four main stages (F1–F4) of geomorphological terrace development and related deposits are recognised using satellite imagery and field observations. The geomorphological terraces have been tectonically uplifted during the Pleistocene so that they dip northwards from the Troodos Mountains until they merge with the Mesaoria Plain. Lithology (e.g. hard diabase versus soft extrusive rock) has exerted an important control on the geomorphology of the Akaki River channel. The F1 terraces and related deposits are well preserved in the lower reaches of the catchment. The F2 terraces are more widely preserved but with few preserved deposits. The F3 erosional surfaces (e.g. strath terraces) and related deposits are widespread up into the higher reaches of the catchment. The F4 to recent geomorphological surfaces and deposits are confined to near the modern river channel. The F1- to F3-aged deposits each include very high-energy mass-flow deposits and somewhat lower-energy traction-flow deposits, with minimal sand preservation. Stages of fluvial aggradation were followed by soil development (e.g. terra rossa). The F1- to F4-aged terraces and related deposits mainly formed in response to a combination of very long-term tectonic uplift and climatic-related change (long term and short term). Tectonic uplift was the dominant driver related to the updoming of the Troodos ophiolite, especially during the earlier time period (F1 and F2), whereas climate-related effects appear to have dominated more recently (F3 and F4). Sedimentary aggradation is likely to have predominated during interglacial periods, while interglacial–glacial transitions (when climate fluctuated) are seen as times of increased incision. Previous correlations of the F1–F4 fluvial deposits with similar deposits elsewhere in Cyprus, including coastal marine carbonate deposits, suggest that the F1 and F2 deposits are likely to be of Middle Pleistocene age and the F3–F4 deposits of Late Pleistocene to Holocene age.