5.a. Correlation of the Vasilikos quarry and valley deposits

The two independently determined stratigraphic schemes can be correlated based on three main related lines of evidence.

1. 1 Geomorphology. The top of the F1 terrace, as seen in Vasilikos Quarry, represents the highest preserved geomorphological surface, as does the F1 throughout the Vasilikos river catchment (Figs 10, 11). These F1 surfaces can be visually correlated from the escarpment c. 1.8 km NW of the quarry (Fig. 3b), across a topographic depression that is occupied by the Limassol–Nicosia highway, to the northward-rising topography (towards Kalavasos). The F1 surfaces in both areas are heavily calcretized, representing prolonged subaerial exposure during which erosional and depositional processes mainly took place at lower topographic levels.

2. 2 Stratigraphy. Of the four stages of development in the Vasilikos river valley (F1–F4), two (F1 and F2) can be recognized on lithological grounds in Vasilikos Quarry. However, the F3 and F4 conglomerates are not developed at Vasilikos Quarry. This reflects post-F2 fluvial incision which located these younger deposits at lower topographic levels near the modern river channel (c. 1 km to the east). The river channel is likely to have migrated eastwards after the F2 deposition as no equivalent of the relatively thick F2 conglomerates is preserved on the opposing eastern margin of the modern river channel.

3. 3 Sedimentology. The F1–F3 deposits show many similar features in both the lower reaches of the river valley and the quarry. The F1 deposits in both areas are sheet-like, extensively distributed at relatively high topographic levels and include, on average, the largest clasts, mainly of ophiolite-derived rocks. The incised F2 deposits in both areas also show marked similarities in both areas, including erosive bases, lenticular (channelized) morphology, sedimentary structures, clast size, clast maturity, matrix type and relative abundance. The intense brown to dark reddish-coloured palaeosols are highly distinctive and occur only on the F3 fluvial deposits in Vasilikos Valley and also depositionally above the F2 conglomerates in the quarry. The occurrence of these palaeosols in the quarry above the F2 conglomerates is at first sight anomalous because F3 deposits (with overlying palaeosols) are incised into F2 conglomerates in the river valley. However, this can be explained by accumulation of the palaeosols on the upper, westerly slopes of F3-related palaeovalley (Fig. 8), well away from the then active channel. Fluvial material derived from the main river channel is absent, and the material accumulated as soils on a weathering and eroding landscape. Similar-coloured palaeosols developed on valley slopes adjacent to the F3-aged river channel, especially in the mid to upper reaches of Vasilikos catchment, especially north of Kalavasos.

5.b. Geomorphological development of the Vasilikos river catchment

In general, the valley profiles have deepened and narrowed through time, especially in the middle and upper reaches (Fig. 10), representing successive stage of incision. However, the channel generally widened and shallowed in the lower reaches, down to the modern coast, largely reflecting the relatively soft rheology of the underlying mudrock (Nicosia Formation).

The geomorphological development of the headwaters of the Vasilikos river catchment to the north of Vasilikos Dam was not studied in detail. However, for >1 km north of the dam the F1–F4 terraces are replaced by a young dendritic drainage pattern (Figs 8, 9a). This feature could represent the development of markedly steeper slopes above relatively resistant ophiolitic rocks (e.g. diabase/gabbro) with correspondingly increased incision and erosion of pre-existing terrace deposits. Structural control (relative uplift) could have a similar effect, although there is no direct evidence of this (see below). Further northwest, within the Arakapas Fault Zone (Fig. 2), the Vasilikos River flows down more gentle slopes, possibly isolated above one or more nick points (although this remains to be tested). Within the Arakapas Fault Zone, well-developed erosional surfaces reappear close to the present-day Vasilikos River. Morphologically, these are similar to the F3 surfaces south of Vasilikos Dam. The associated deposits are mainly thin (<5 m) ophiolite-derived conglomerates with a reddish sandy matrix, covered by distinctive, reddish terra rossa palaeosols.

South of Vasilikos Dam, the dominant control on the geomorphology within the upper, middle and lower reaches is interpreted to be lithology, as supported by the geological map (Fig. 8) and the topographic profiles (Figs 10, Fig. 11). The upper reaches (Fig. 11a–c) are underlain by the Lower Pillow Lavas of the Troodos ophiolite near Kalavasos Dam, and by the Upper Pillow lavas towards Kalavasos (Pantazis, Reference Pantazis1967). The Lower Pillow Lavas are predominantly massive and pillowed flows with much fragmental material (lava breccia and hyaloclastite) that erodes readily. The F3 deposits directly overlie the Lower Pillow Lavas on the east side of the valley, where they have been largely removed by small tributary channels. In contrast, the F3 deposits are better preserved on the west side of the valley where the bedrock is more resistant to erosion. The Upper Pillow Lavas, although composed of comparable extrusive lithologies, are generally more indurated in this area as a result of hydrothermal alteration and sea-floor weathering and support locally steeper valley slopes (Pantazis, Reference Pantazis1967), as reported from the north-Troodos Akaki river catchment (Main et al. Reference Main, Roberston and Palamakumbura2016).

In the middle reaches (Fig. 11e, f), the bedrock is dominated by chalks of the latest Cretaceous–Oligocene Lefkara Formation (Fig. 2). The Vasilikos river valley gradually narrows southwards, culminating in a pronounced constriction (just south of Kalavasos), which is coincident with erosionally resistant bedded and nodular chert making up the Middle Lefkara Formation (Pantazis, Reference Pantazis1967). Incision of this highly resistant interval resulted in steep channel margins, leaving only a narrow preserved rib of F2 deposits on the steep westerly slope and a thin strip of F3 deposits on the lower eastern valley slope, without a preserved F3 terrace. The local development of the F4 terrace on the lowest west side of the valley is interpreted as the inner bend of a small meander within the previously incised valley, where locally reduced stream velocities resulted in fluvial aggradation.

The lower reaches (Fig. 11g–j), where the valley broadens and shallows, are underlain initially by the soft-weathering limestones, marls, chalks and local evaporites of the Miocene Pakhna Formation, and further down-catchment by mudrocks and marls of the Pliocene – Early Pleistocene Nicosia Formation. Asymmetrical topographic profiles contrast with further upstream (Fig. 11a–c, e). This, and the marked variation in the width of the preserved F4 terraces, points to meandering of the river channel in this area.

5.c. Fluvial processes

Poorly to moderately sorted, clast-rich, matrix-supported conglomerates with outsized clasts (>1 m) are best represented by the F1 conglomerates (Fig. 7a), which are interpreted as very high-energy mass-flow accumulations, i.e. debris-flows and hyperconcentrated-flow deposits (Harvey et al. Reference Harvey, Mather, Stokes, Harvey, Mather and Stokes2005; Waters et al. Reference Waters, Jones and Armstrong2010). Spasmodic flash floods introduced packages of similar-sized clasts of similar composition, although individual depositional units vary (see ‘Sediment provenance’, below). Such flash floods were highly erosive, as inferred from their irregular, eroded basal contacts (Fig. 12b). In the Vasilikos river catchment, bedrock chalks were locally scoured into to form depressions that were infilled by foresets, marking the base of high-energy conglomerates. North of Kalavasos (Fig. 12a), clasts in the F1 conglomerates are relatively small, well sorted and lenticular, with some clast imbrication. These conglomerates were deposited from a weaker flow with a higher degree of traction current activity compared to the coarser deposits preserved further south. The finer chalk-rich conglomerates are likely to have accumulated in a relatively marginal position where stream energy was reduced. Conglomerates, which are relatively well sorted and show clast imbrication, generally to the S-SE, represent the accumulation from sustained traction-flow processes (Collinson, Reference Collinson and Reading1996; Waters et al. Reference Waters, Jones and Armstrong2010). Locally developed tabular foresets, mainly in the F1 and F2 conglomerates(Fig. 7e), are indicative of foreset progradation during short periods of high-energy, sustained flow when clasts rapidly infilled local accommodation space (Miall, Reference Miall1996). Sorting, clast size and imbrication commonly decrease upwards within individual depositional units (Fig. 7f, 14.F3a), pointing to waning flow, particularly in the upper levels of the F3 fluvial deposits within the Vasilikos river valley. The fluvial processes previously identified within Vasilikos Quarry (Waters et al. Reference Waters, Jones and Armstrong2010) are also largely applicable to the equivalent-aged river valley deposits (and so will not be discussed again here).

5.d. Alluvial settings

Most of the margins of the F1 channels are not preserved owing to extensive erosion of the older terrace deposits. However, discrete conglomerate-filled channels are locally preserved within the F2 deposits, and more commonly within the F3 and F4 deposits (Figs 8, 11). These are all interpreted as relatively marginal facies because the coeval channel axis sediments were mostly eroded during subsequent incision events. The sedimentary structures and lithologies of the conglomerates are generally indicative of braided or semi-braided stream accumulation (Miall, Reference Miall1996; Jones et al. Reference Jones, Frostick and Astin2001), including the F1 and F2 deposits in Vasilikos Quarry (Fig. 6). Palaeocurrent evidence (mainly clast imbrication) from the F1–F3 deposits indicates consistent flow to the S-SE and does not confirm meandering flow in our F2 conglomerate in Vasilikos Quarry (cf. Waters et al. Reference Waters, Jones and Armstrong2010). On the other hand, geomorphological differences on either side of the channel in the southern reaches of the Vasilikos River, as far north as near Kalavasos (Figs 10, 11), suggest that some of the F4 deposits are likely to have accumulated from a meandering river. The relatively well-sorted silts, especially the thin, laterally extensive F4 sheet-like deposits in the lower reaches, can be interpreted as overbank deposits related to channel avulsion (Nichols & Fisher, Reference Nichols and Fisher2007).

The aggrading F2 succession in Vasilikos Quarry is of particular interest (Figs 5, Fig. 6). This is interpreted as a remnant of a relatively wide and deep channel that was cut into the F1 conglomerates. The eastern part of this channel is not preserved owing to subsequent F3 downcutting and relocation of the active channel to the east. The dipping erosional surface (Figs 5, Fig. 6, 7c) represents a section through this F2 channel western margin. The steep, undulating nature of the basal (near-axial) contact resulted from erosion into the Nicosia Formation. Following this incision, three-phase aggradation took place (all within F2), two phases of poorly sorted, clast-rich, clast or matrix-supported, lenticular conglomerates, and one of medium to coarse-grained sands, interspersed with isolated conglomerate channels. The highly erosive base of the upper conglomeratic unit (Fig. 6) is suggestive of a high-energy, flashy mode of emplacement. Both of these conglomerate intervals exhibit stream-flow characteristics, such as size sorting and clast imbrication, that suggest a strong component of perennial flow during deposition (Waters et al. Reference Waters, Jones and Armstrong2010). The two main conglomeratic intervals are interpreted to have accumulated during periods of relatively high-magnitude stream-flood events. The markedly lenticular nature of the sand and conglomerate lenses within both of the conglomeratic packages (Fig. 6) resulted from the switching of channels within an overall semi-braided setting. The decreasing clast size, clast imbrication and local tabular foreset bedding point to less flashy, more sustained perennial flow in the upper levels of both of the conglomeratic intervals. The stacked morphology of some isolated conglomerate channels, mainly between the two conglomeratic intervals (Fig. 6), indicates repeated short-term cutting and filling of relatively immobile channels. However, other adjacent similar-sized channels were more mobile. The transition from the uppermost F2 unit to the overlying palaeosols (equivalent to F3) is interpreted to represent waning flow. The aggrading F2 unit in the quarry demonstrates a variable flow evolution within a single major incised depositional package, which is also likely to be applicable to the less well-preserved terrace deposits within the Vasilikos Valley.

Coarse-grained F3-aged sediments are well developed in the Vasilikos Valley, in contrast to Vasilikos Quarry where they are absent, owing to narrowing of the incision, resultant channel abandonment and relocation of the active channel eastwards after F2 accumulation ended. The irregular, undulating nature of the base of the F3 infill in the Vasilikos Valley (Fig. 14.F3a, b) is indicative of erosional downcutting. The immature textures and lenticular character (Fig. 14.F3c, d) of the conglomerates are indicative of high-energy flash floods interspersed with periods of more sustained background flow. The smaller clasts observed at the top of the infill (Fig. 14.F3a–d) indicate decreasing energy during waning flow, prior to channel abandonment.

The mainly silty, sheet-like infill of the F4 deposits mainly represents overbank deposits from the axial channel that probably meandered, and was later incised to its present level in several stages (Gomez, Reference Gomez1987). During and after F4 deposition large volumes of coarse material, as exposed in the present-day river bed, continued to bypass the coastal plain and accumulate offshore.

5.e. Sediment provenance

Around the western, northern and eastern peripheries of the Troodos Massif, the outcrops are distributed in a broadly radial pattern, with increasingly higher-level units outwards (Constantinou, Reference Constantinou1995). As a result, for any given clast lithology (e.g. diabase; chert), in many areas (e.g. Akaki river catchment; Main et al. Reference Main, Roberston and Palamakumbura2016) the provenance of the clasts can be specified based on lithology (i.e. minimum/maximum distance of transport). However, this straightforward approach breaks down in the Vasilikos river catchment because the outcrops of ophiolitic rocks to the north of Kalavasos Dam are variably distributed, owing to the highly tectonized nature of the E–W-trending Arakapas Fault Zone and the Limassol Forest area to the south (Fig. 2). Despite this limitation, the derivation of sedimentary rock clasts within the Vasilikos river catchment can be related to the well-organized southward-younging Maastrichtian–Pliocene stratigraphy (Bagnall, Reference Bagnall1960; Pantazis, Reference Pantazis1967) (Fig. 8).

Clasts of the same range of lithologies occur in all of the F1–F4 deposits, which suggests that the source area exposures did not change significantly during the development of the Vasilikos River. There is a higher proportion of ophiolitic clasts in the upper reaches, with chalk clasts first appearing in the middle reaches, where the river starts to flow over the Lefkara Formation (Fig. 8). There is variable mixing of relatively far-travelled ophiolite-derived clasts (mostly diabase and microgabbro) and more locally derived sedimentary clasts (Fig. 14). The ophiolite-derived clasts are mostly well-rounded and smooth-surfaced (Fig. 13c, f) compared to the chalk clasts (Lefkara Formation) that are commonly subangular to angular, blocky or elongate (Fig. 13c, d). These differences in textural maturity represent a combination of transport distance, abrasion during overall transport and the tendency of some sedimentary rocks, especially bedded chert, to erode into highly resistant angular-sided, tabular clasts (e.g. Fig. 13c, top left). In agreement, studies of recent Cyprus beach conglomerates show that chert is strongly overrepresented (by volume) compared to source outcrops, indicating the very high preservational potential of chert (Garzanti et al. Reference Garzanti, Andò and Scutellà2000). Similar preferential chert preservation is represented by the local abundance of chert clasts in some of the Vasilikos valley conglomerates. In addition, there is some evidence of multi-cycle erosion and transport during which some clasts from higher terraces were reworked into lower ones (e.g. in Vasilikos Quarry, Fig. 6 inset). This particularly results in anomalously large or well-rounded clasts of ophiolitic rocks (mostly diabase) (e.g. Fig. 13a), as also noted in the north-Troodos Akaki river catchment (Main et al. Reference Main, Roberston and Palamakumbura2016).

Clast counting of the F1 conglomerate in Vasilikos Quarry previously indicated a predominance of diabase/microgabbro compared to basalt and sedimentary rocks, with only minor basic intrusive rocks and negligible ultramafic rocks (AJ Poole, PhD thesis, Univ. Edinburgh, 1992; Poole & Robertson, Reference Poole, Robertson, Robertson, Emeis, Richter and Camerlenghi1998). The F2 conglomerates, where previously sampled, comprised a more even distribution of the above rock types (AJ Poole, PhD thesis, Univ. Edinburgh, 1992; Poole & Robertson, Reference Poole, Robertson, Robertson, Emeis, Richter and Camerlenghi1998). Within the Vasilikos Valley, diabase and microgabbro clasts dominate, together with rare gabbro, very rare ultramafic rocks (weathered serpentinite) and rare, localized jasper (iron-rich chert) related to the Troodos extrusive rocks (Fig. 12f). The relative clast abundances reflect the widespread availability of erosionally resistant diabase and gabbro from the higher reaches of the Vasilikos River, north of Kalvassos Dam (Fig. 8). On the other hand, despite their widespread outcrop, basaltic clasts are sparse other than directly overlying the ophiolitic extrusive rocks. This reflects the tendency of the basalt to weather mainly to fine-grained silt-sized material, as reported in the north-Troodos Akaki catchment (Main et al. Reference Main, Roberston and Palamakumbura2016). Despite the existence of a large outcrop of serpentinized rocks that begins c. 2 km NW of the dam site (Pantazis, Reference Pantazis1967), ultramafic ophiolitic rock clasts are notably sparse, reflecting alteration to soft-weathering serpentinite.

5.f. Palaeosol development

Both the Vasilikos river valley and Vasilikos Quarry are characterized by widespread development of brownish to reddish palaeosols (Fig. 6; see also Supplementary Material available online at https://doi.org/10.1017/S0016756819001134). In the Vasilikos Valley, strongly reddish terra rossa-type palaeosols occur within and directly overlying the F3 fluvial deposits (Fig. 13b). Palaeosols occur elsewhere in the relative chrononology (e.g. late Pleistocene) near Kalavasos (Schirmer, Reference Schirmer1998; Kinnaird et al. Reference Kinnaird, Robertson, Robertson, Parlak and Ünlügenç2013). However, these are mainly brownish rather than reddish, and less well-developed. The facies similarities and position in the stratigraphy support a correlation of the very well-developed, intensely red terra rossa palaeosols in the quarry with the F3 deposition (and associated geomorphical surfaces) in the valley. Similar terra rossa palaeosols are reported from the same relative stratigraphic level (equivalent to F3) in the north-Troodos Akaki canyon (Main et al. Reference Main, Roberston and Palamakumbura2016) and the Kyrenia Range (Palamakumbura & Robertson, Reference Palamakumbura, Robertson, Kinnaird, Van Calstern, Kroon and Tait2016a).

In the quarry, the transition between clastic deposition and palaeosols (Fig. 6 log b; see also Supplementary Material available at https://doi.org/10.1017/S0016756819001134) is interpreted as the result of soil formation, alternating with fluvial sand accumulation, prior to channel abandonment. Southward thickening of the palaeosols suggests more extensive soil formation away from the river channel. In places, small (< several metres deep) steep-sided channels cut the palaeosols and are infilled with a mixture of reworked (rounded) ophiolite-derived clasts and locally derived (highly angular) Lefkara Formation chalk clasts (see Supplementary Material available online at https://doi.org/10.1017/S0016756819001134). The uppermost, darkest red (most iron-rich) palaeosol is indicative of highly favourable conditions for soil formation and/or a relatively long period of accumulation. The palaeosols in the quarry developed on the very gentle upper slopes of the F3 river channel that was by then located well to the east and at a lower topographic level. Partially eroded F1 conglomerate to the SW contributed texturally mature, ophiolite-derived clasts (mostly diabase) to the locally overlying palaeosol (Fig. 6, section, west end). Elsewhere, clasts are scattered through the palaeosols; these are randomly orientated and range from well-rounded to highly angular. The clasts are likely to have been washed downslope individually during wet periods, without sorting. Where present, localized small conglomerate-filled channels within the palaeosols in the quarry are interpreted as high-energy flash-flood events, which mainly reworked clasts from the F1 or F2 conglomerates.

In general, local topography strongly influenced palaeosol morphology and thickness, varying from thin sheets on flat areas (e.g. lower reaches), to locally thickened lenses in some hillslope areas (middle and upper reaches). The palaeosols in the quarry are thicker (several metres) and darker in colour (more iron-rich) compared to most of those overlying the F3 deposits and related surfaces in the Vasilikos Valley; these are relatively thin (tens of cm), grey-brown to reddish (Fig. 13b). This is probably because a relatively long time was available for palaeosol formation in the distal valley slope after major channel abandonment (i.e. quarry), uninterrupted by major fluvial input or mass-wasting processes. In addition, bright red palaeosols developed on correlative F3 surfaces including ophiolite-derived conglomerate in the higher reaches of the Vasilikos river catchment, within the Arakapas Transform Fault Zone (see Supplementary Material available online at https://doi.org/10.1017/S0016756819001134).

Palaeosols are well known to be climate-influenced. Relatively warm, moist periods generally favoured the formation of brownish/reddish terra rossa-type palaeosols (Kraus, Reference Kraus1999; Schaetzl & Anderson, Reference Schaetzl and Anderson2005; Celma et al. Reference Celma, Pieruccini and Farabollini2015). The presence of roots/rootlets and charcoal within the palaeosols is indicative of a well-developed vegetation cover, with an increasing number of root traces up-sequence as the soils became more developed (see Supplementary Material available online at https://doi.org/10.1017/S0016756819001134). The terra rossa could include a significant proportion of aeolian dust as elsewhere in the Mediterranean region (e.g. Mallorca, Spain; Muhs et al. Reference Muhs, Budahn, Avila, Skipp, Freeman and Patterson2010), although geochemical analysis is needed to test this possibility.

5.g. Colluvium formation

Landscapes tend towards equilibrium stability (Hurst et al. Reference Hurst, Mudd, Walcott, Attal and Yoo2012). As a result, material tends to move from high to lower topographic elevations, particularly on valley sides. Hillslope readjustment processes have therefore played an important role in the development of the Vasilikos Valley, especially in the topographically steeper upper to middle reaches. The readjustment-related deposits are of two types, one associated with the F1 and F2 surfaces which is conglomeratic (e.g. Nemec & Kazanci, Reference Nemec and Kazanci1999) and one with the F3–F4 surfaces, which is mainly composed of silt-sized material (harvara).

5.g.1. Conglomeratic colluvium

Chalky conglomeratic or breccia-like colluvium (>20 m thick) overlies the F2 erosion surface in the upper reaches near Vasilikos Dam (Fig. 15b). This material was derived from the Lefkara Formation (Fig. 8) that is exposed on the upper, easterly slopes of the Vasilikos river catchment (c. 2 km away and >100 m topographically higher). This colluvial conglomerate is matrix-rich (75 %), poorly sorted and contains >95 % angular to subangular chalk clasts, without imbrication (Fig. 15c). In places, the deposits fill depressions in the underlying extrusive igneous rocks, indicating that that they were crudely channelized.

Fig. 15. Field photographs of calcrete (caliche), colluvium palaeosol in the Vasilikos river catchment. (a) Pillow lava (A) overlain by poorly developed palaeosol (B) and then by chalky talus (C) (talus); north of Kalavasos Dam. (b) Pillow lava (A) overlain by lenticular, poorly stratified chalky talus (B) that overlies the F2 erosion surface; derived from the Lefkara Formation outcrop on the ridge above (to the NE); view from Kalavasos Dam. (c) Unsorted talus rich in angular clasts of bedded chert and chalk; derived locally from the Lefkara Formation (above the F3 erosion surface) on the east side of the steep-sided valley opposite Kalavasos. (d) Pebbly colluvium (buff-grey) (harvara) at the base (A), overlain by greenish pebbly lenticular alluvium (B), then laterally continuous reddish pebbly palaeosol (C) and finally by additional pebbly colluvium (D); overlying F3 surface, NW of Kalavasos. (e) Buff-coloured calcareous sandy silt (A), cut by rootlet (B); intercalation with reddish palaeosol from the F3 unit in Vasilikos Quarry; upper NW face; interpreted as a poorly developed soil. (f) Lower units of harvara (pale) and palaeosol (brownish) (A), overlain by less steeply dipping harvara, palaeosol and young superficial deposits (B). The probable explanation of the angular discordance is back-tilting, then transgression of similar material; above the F3 surface; W margin of palaeovalley N of Kalavasos (outcrop since degraded).

Chalky conglomeratic colluvium also forms exposures (up to c. 0.5 km across) above ophiolitic lavas elsewhere within the upper reaches of the Vasilikos Valley (Pantazis, Reference Pantazis1967). This chalky conglomerate, like the exposure near the dam, appears to have mainly formed post-F2 incision but pre-F3 incision. In addition, comparable conglomeratic colluvium forms widespread exposures (up to c. 2 km across) on the southward-facing slopes of the Arakapas Transform Fault valley (c. 7 km N of the dam). In this area, the Lefkara Formation chalks were subsequently eroded leaving thick (tens of metres) chalky conglomerates, isolated from their source outcrop.

The chalky conglomerates and breccias as a whole accumulated in response to erosion of relatively soft-weathering chalk, followed by downslope movement by mass-flow processes. Erosive power was sufficiently strong to incise locally into basaltic lavas, although these are likely to have been strongly weathered (Fig. 15a). After incision of the F2 palaeovalley, which increased sediment accommodation space, the higher valley slopes underwent mass wasting of chalk to form the clast to matrix-supported conglomerate/breccia which then accumulated on the F2 erosion surface. Remnants of this coarse colluvial material remain after later incision and erosion (F3, F4).

Within the middle reaches of the Vasilikos Valley, the steeply sloping margins of the incised F3 surface are mantled by fallen blocks of conglomerate that were locally derived from the topographically higher F2 terrace. In many places, such as SW of Kalavasos, there is a clear change in slope beneath the F2 surface, which is initially steep and then flattens out downwards. The slope change corresponds to the occurrence of numerous irregularly distributed conglomerate blocks (up to 10 m long × <5 m thick). The blocks are lithologically similar to the F2 conglomerate that is locally preserved above. These F2 conglomerates were armoured by calcrete, incised (related to F3 downcutting), and then locally collapsed downslope as detached blocks. Mass wasting of blocks of lithified conglomerate has therefore played a role in slope adjustment, at least locally.

5.g.2. Silty and marly colluvium

Sloping F3 surfaces are commonly mantled by variably dipping, variably stratified, impure marls and silts (harvara), which are locally interbedded with matrix-supported conglomerates and/or grey to brown palaeosols (Fig. 15d). These deposits are very widespread, especially on the western side of the valley, in the middle reaches. The deposits range from thin (typically several metres), irregular veneers, especially on upper slopes, to lenticular slope cones (tens of metres thick) where valley re-entrants merge with valley floors. Downslope and axially, the colluvial deposits are increasingly mixed with fluvial conglomerate. The broad, sloping F3 valley surfaces were particularly well suited to harvara accumulation and were preserved from Holocene erosion related to their topographic position above the modern-day river channel.

The harvara formed preferentially on carbonate-rich bedrock (Schirmer, Reference Schirmer1998). However, it can also be reworked downslope onto other lithologies, as seen in the Vasilikos Valley near the dam, where it overlies ophiolitic rocks. Harvara commonly forms debris cones at the toes of valley slopes (<10 m thick), although it can also occur as thin sheets or lenses on more gently inclined surfaces.

Individual stratified harvara deposits, as well exposed at Kalavasós Márkou (see above), begin with calcareous silt with rock fragments, interpreted to represent unstable slopes with limited binding vegetation. The presence of scattered relatively large, angular clasts in some of the harvara points to ‘flashy’ coarse sediment supply. Harvara layers then fine-upwards into more homogeneous silty marl that is interpreted to have accumulated under more stable slope conditions.

The palaeosols in Vasilikos Quarry are interbedded with thicker intervals of pale calcareous silts, commonly with rootlets and variably calichified (Figs 6, 15e). These sediments are interpreted as poorly developed palaeosols, mixed with terrigenous material, that accumulated on a gently sloping land surface away from the active river channel.

Harvara in Cyprus has been interpreted as mainly the product of slow periglacial mass wasting (solifluction), coupled with downslope mass movement. Initially strong, but waning, climatically controlled erosion–redeposition characterized glacials, followed by humic soil formation on a forested land surface during interglacials (Schirmer, Reference Schirmer1998). During glacial periods, mechanical erosion (e.g. freeze–thaw; frost shattering) provided a large amount of immature angular material, explaining the presence of relatively large (outsized) angular clasts (e.g. Lefkara Formation chalk) within the harvara, compared to generally smaller and more texturally mature (rounded) clasts within the overlying terra rossa when the landscape was more vegetated. Harvara therefore developed cyclically as climate changed, varying in thickness and facies according to the duration and intensity of climatic downturms and the prevailing slope conditions. A similar influence of vegetation on run-off is inferred from other areas including the Late Quaternary of the Sparta area, Greece (Pope & Wilkinson, Reference Pope, Wilkinson, Harvey, Mather and Stokes2005).

During harvara accumulation, hillslopes approached or exceeded 30°, which favoured sediment transport by dominantly nonlinear processes such as mass flow and downslope creep. Sediments that moved downslope by such diffusive processes were shielded from chemical weathering that commonly affected subaerially exposed material.

Aeolian processes are likely to have contributed to harvara formation (Schirmer, Reference Schirmer1998), which is consistent with the abundance of Pleistocene aeolianites in adjacent areas (e.g. Israel coast plain) (Frechen et al. Reference Frechen, Neber, Tsatskin, Boenigk and Ronen2004). However, the Cyprus harvara is not necessarily equivalent to fine-grained colluvium in general, which is believed to have formed at various times and under varying climatic conditions (Nemec & Kazanci, Reference Nemec and Kazanci1999).

Taken together, the chalky conglomerate/breccia and the finer-grained colluvium (harvara) were influenced by a range of processes including slope angle (and slope change), sediment accommodation space (related to incision), climate (and climate change) and source rock. Source rock was important, especially the outcrops of Maastrichtian–Palaeocene marly chalks which are particularly soft-weathering and supplied large volumes of chalky material. Relatively steep slopes were also important in concentrating colluvium in slope toes above terraces (especially F3). Chalks are also extensive in the NE-Troodos Akaki catchment (Main et al. Reference Main, Roberston and Palamakumbura2016). However, there, chalky colluvium is minimal mainly because the adjacent slopes (e.g. F3) were much more subdued.

5.h. Calcrete and caliche formation

The fluvial terraces are capped by a calcareous crust (kafkalla; see Section 2 above), which is generally thickest (up to several metres) and most pervasive on the topographically highest and thus older terraces (F1 and F2) (Fig. 13c), reflecting prolonged subaerial (or near-subaerial) exposure. The uppermost levels of the conglomerate terraces are commonly cemented by calcrete (up to several metres thick), with or without a kafkalla capping. Beneath this, the matrix of the conglomerates at all levels commonly contains caliche nodules (see Supplementary Material available online at https://doi.org/10.1017/S0016756819001134). Nodular caliche is widespread especially within the F3 and F4 finer-grained fluvial sediments.

Caliche forms in a semi-arid climate with seasonal rainfall, similar to today (Arakel, Reference Arakel1982). Recent studies of other areas (e.g. Sorbas basin, Spain) suggest that suitable climatic conditions for caliche formation (similar to today) existed during several Pleistocene warm intervals, prior to the Holocene (MIS 1–5) (Candy et al. Reference Candy, Rose and Lee2006; Candy & Black, Reference Candy and Black2009). Caliche is also reported from areas of high but seasonal rainfall and relatively high temperature (Retallack, Reference Retallack2001). Given that caliche relates to fluid flow, precipitation and clastic sediment replacement, it may form over a prolonged time period, and might even develop cyclically as climatic conditions change assuming that it remains within the seasonally affected profile. Whole-rock radiometric ages of caliche therefore need to be treated with some caution.

5.i. Development of the Vasilikos catchment through time

Combined with the quarry exposure, the river valley geomorphology and deposits allow the progressive development of the Vasilikos river catchment to be reconstructed (Figs 16, 17; Table 1).

Fig. 16. Interpretative maps showing the inferred stages of fluvial deposition in the Vasilikos River and its tributary. (a) F1: broad, weakly channelized; (b) F2: incised narrower channels; (c) F3: further incised, narrower channels (only shown where known to have existed); (d) F4: narrow further incised channel (only shown where known to have existed).

Fig. 17. Block diagram showing the restored development of the Vasilikos River and its fluvial sediment infill. (a) F1: Mid-Pleistocene, broad semi-braided fluvial conglomerates; (b) F2: Middle Pleistocene, confined semi-braided to locally channelized fluvial conglomerates; (c) F3: late Mid – early Late Pleistocene, incised, confined fluvial deposits with marginal overbank deposits and palaeosols; (d) F4: Late Pleistocene; further incision, confined fluvial deposits and overbank silts.

Table 1. Summary of the facies/stratigraphy, main field evidence, interpretation and age estimates of the primary deposits exposed in Vasilikos Quarry and the adjacent Vasilikos river catchment. Material formed by secondary (diagenetic) processes (e.g. caliche) is excluded

The scene was set during the early, focused uplift of the Troodos Massif (Poole & Robertson, Reference Poole and Robertson1991). As a result, fully marine shelf deposition of the Pliocene – early Pleistocene Nicosia Formation (mud/marl) gave way to sand and conglomerate lenses, interbedded with bioturbated marine marls, rich in macrofossils. The interval records the progradation of a shallow-marine fan delta generally towards the SE (JE McCallum, unpub. PhD thesis, Univ. Edinburgh, 1989), although with hints of meandering streams. This was followed by a thin and probably short-lived interval of non-marine fan-delta accumulation. Each conglomerate lens is likely to represent a flash flood event, with the higher proportions of generally larger clasts representing deposition from the highest energy flows.

The regionally distributed F1 conglomerate (Fanglomerate Group) accumulated during very rapid uplift of Troodos Massif. This background tectonic control coincided with a humid climate that facilitated major bedrock erosion, coarse clastic sediment supply and development of sheet-outwash fans, radially around the Troodos Massif (Poole and Robertson, Reference Poole and Robertson1991, Reference Poole, Robertson, Panayides, Xenophontos and Malpas2000). Erosion and associated incision can be accentuated during times of climate deterioration and vegetation loss, as inferred in Mallorca (Spain) during the last 140 ka (Rose et al. Reference Rose, Meng and Watson1999). Studies in other areas (e.g. Makran Range) suggest on the other hand that incision and terrace abandonment were accentuated during the transition to, and also during, warm, humid periods (Bridgland & Westaway, Reference Bridgland and Westaway2008; Wegmann & Pazzaglia, Reference Wegmann and Pazzaglia2009; Kober et al. Reference Kober, Zeilinger, Ivy-Ochs, Dolati, Smit and Kubik2013).

The F1 conglomerates, as in Vasilikos Quarry and in the highest fluvial terraces in the Vasilikos river catchment, conform to the previously documented overall radial distribution pattern around the Troodos Massif (Poole & Robertson, Reference Poole and Robertson1991, Reference Poole, Robertson, Panayides, Xenophontos and Malpas2000). The palaeocurrent evidence, including the foresets in the F1 and F2 deposits of the quarry and the clast imbrication in all of the fluvial terraces studied, indicates dominant flow towards the SE, which is in keeping with uplift and erosion centred on Mount Olympos (Poole & Robertson, Reference Poole and Robertson1991, Reference Poole, Robertson, Panayides, Xenophontos and Malpas2000).

The topography of the F1 fluvial distributary in the lower reaches is envisaged as a broad, shallow semi-braided channel, which transported very coarse material from the ophiolitic hinterland via a series of high-energy traction and mass-flow events (Figs 16a, 17a). The mid to higher reaches of the F1 distributary cannot be inferred owing to lack of sufficient deposits.

The F2 deposits accumulated in a discrete, constrained channel that was incised into the F1 deposits or into bedrock (Figs 16b, 17b). This is specifically demonstrated in Vasilikos Quarry, where the F2 conglomerates cut through the F1 conglomerates into Late Pliocene – Early Pleistocene marine marls/mudrocks of the Nicosia Formation (Figs 5, 6). The F2 conglomerates extend into the upper reaches of the Vasilikos river valley (Fig. 11), where the pre-existing, relatively broad F1 channel was incised by a narrower, steeper-sided channel. Further indications of the F2 channel-filling processes come from the quarry, where the lower of the two aggrading conglomeratic intervals (Figs 5, 6) shows evidence of deposition near the threshold of a change between braided and channelized deposits. In some places, these conglomerates have similar depositional features to the F1 conglomerates, with lateral continuity for tens of metres or more and evidence of sandy and pebbly bars. However, in places conglomerates are strongly channelized and stacked vertically or obliquely.

The F3 surfaces in the Vasilikos Valley record profound erosion which removed most of the pre-existing conglomerates, leaving only fringing fluvial deposits as terraces (Figs 16c, 17c). In the middle and upper reaches of the catchment, the F3 channel incised pre-existing channels. In contrast, in the lower reaches, above softer lithologies (Pakhna and Nicosia formations), the channel narrowed and deepened into bedrock. The western margin of the F2 channel infill, represented by the quarry outcrop, was abandoned and covered by mainly fine-grained deposits in the form of alternating palaeosols and pale calcareous silts.

After F3 deposition, further incision created a range of geomorphologies and deposits (Figs 16d, 17d). A slot-like gorge was incised in the upper reaches, with minimal preserved sediment (Figs 10, 11). A comparable but deeper (c. 25 m) slot-like gorge formed during equivalent late-stage geomorphological development of the Akaki canyon, NE Troodos margin (Main et al. Reference Main, Roberston and Palamakumbura2016), and has also been noted elsewhere around the Troodos Massif (unpublished data). The finer-grained F4 deposits mostly represent overbank deposits, probably from a meandering channel, which spilled over a broad, low-amplitude palaeovalley in the lower reaches, south of Kalavasos. The modern-day channel in the lower reaches ranges from a shallow, well-constrained channel (south of Kalavasos) to a broader, less constrained semi-braided channel towards the coast.

5.j. Major controls of erosion and aggradation

Long-term tectonic uplift focused on Mount Olympos was the dominant control of geomorphology and fluvial deposition (Poole & Robertson, Reference Poole and Robertson1991). However, shorter-term climatic changes (on Milankovitch timescales) also played a key role (Poole & Robertson, Reference Poole, Robertson, Panayides, Xenophontos and Malpas2000; Waters et al. Reference Waters, Jones and Armstrong2010). Similar climatic influence is inferred for many other areas undergoing tectonic uplift, including Calabria (Massari et al. Reference Massari, Capraro and Rio2007) and south-central Australia (Quigley et al. Reference Quigley, Sandiford and Cupper2007). Eustatic sea-level change is also likely to have played a role by lowering the base level of erosion, particularly at the near-coast quarry site (now c. 40–80 m asl). Eustatic sea-level oscillations of up to c. 130 m took place during the Last Glacial Maximum (19 000 and 30 000 years ago) (Lambeck et al. Reference Lambeck, Esat and Potter2002) and presumably affected all areas of coastal Cyprus. The incised F4 channels, including the slot-like gorge in the upper reaches (south of the dam), could relate to northward retreat of a sea-level-change-induced nick point, similar to that suggested for the NE-Troodos Akaki river catchment (Main et al. Reference Main, Roberston and Palamakumbura2016). Elsewhere in the Mediterranean, fan deposition on the Cabo de Gata coast, SE Spain, is interpreted to have responded to base-level change with increased erosion and incision (Harvey, Reference Harvey2002).

5.k. Timing of erosion and aggradation

Absolute age constraints on the direct age of the non-marine Pleistocene surfaces and deposits within the Vasilikos river catchment unfortunately remain very limited, restricted to two radiocarbon dates and three OSL age estimates of palaeosols, together with supporting OSL age profiling (Kinnaird et al. Reference Kinnaird, Robertson, Robertson, Parlak and Ünlügenç2013), and one whole-rock U-series caliche age (Waters et al. Reference Waters, Jones and Armstrong2010) of debatable significance (see below). Despite these limitations, some older ages can be suggested for the earlier deposits, mainly based on magnetostratigraphy of deposits in S Cyprus and correlations with radiometrically dated shallow-marine, coastal carbonates.

Palaeomagnetic studies of Pleistocene fine-grained deposits from the western, southern and eastern periphery of the Troodos Massif indicate a normal magnetic polarity for both the fluvial and littoral–marine sediments as a whole (Kinnaird et al. Reference Kinnaird, Robertson and Morris2011; Weber et al. Reference Weber, Schirmer, Heller and Bachtadse2011) (i.e. post-781 ka; Cohen et al. Reference Cohen, Finney, Gibbard and Fan2013). The F2 and F1 deposits (and by extension the associated surfaces) are not dated anywhere in Cyprus, largely owing to the absence of preserved aragonitic coral suitable for dating of correlative shallow-marine deposits. The older deposits (F1 and F2), originally inferred to be early–mid Pleistocene (Poole & Robertson, Reference Poole, Robertson, Robertson, Emeis, Richter and Camerlenghi1998, Reference Poole, Robertson, Panayides, Xenophontos and Malpas2000), are now redefined as Middle Pleistocene age, following the reclassification of the Pliocene–Pleistocene boundary (from 1.806 Ma to 2.588 Ma) (see Cohen et al. Reference Cohen, Finney, Gibbard and Fan2013). However, it can be assumed that these two major incision–aggradation cycles correspond to major sea-level excursions prior to MIS 7, of mid-Middle Pleistocene age, potentially MIS 9, MIS 11 and possibly older (see Palamakumbura et al. Reference Palamakumbura, Robertson, Kinnaird, Van Calstern, Kroon and Tait2016b). Large-scale fluvial conglomerate accumulation (pre-F1, F1 and F2) therefore took place during Early–Middle Pleistocene time when the aggrading marine to non-marine fan-delta system is included. Although younger, the two correlative aggrading conglomerate intervals (F2) in the quarry are also inferred to be of mid-Middle Pleistocene age. The reported 59 ka (Late Pleistocene) whole-rock age (Late Pleistocene) of caliche from the upper level of these conglomerates (Waters et al. Reference Waters, Jones and Armstrong2010) therefore appears to be too young, and is reinterpreted as a diagenetic age.

The relative chronology of the F1–F4 deposits in the Vasilikos river catchment is similar to elsewhere around the periphery of the Troodos Massif (Poole & Robertson, Reference Poole, Robertson, Robertson, Emeis, Richter and Camerlenghi1998, Reference Poole, Robertson, Panayides, Xenophontos and Malpas2000), notably the NE-Troodos Akaki river catchment (Main et al. Reference Main, Roberston and Palamakumbura2016). In addition, similar stages of geomorphologic development have been established in the Kyrenia Range, N Cyprus (Palamakumbura & Robertson, Reference Palamakumbura, Robertson, Kinnaird, Van Calstern, Kroon and Tait2016a, b; Palamakumbura et al. Reference Palamakumbura, Robertson, Kinnaird and Sanderson2016a, b). Shallow-marine terrace deposits, both around the periphery of the Troodos Massif and in the Kyrenia Range, have been radiometrically dated by means of U-series disequilibrium dating of Cladocora solitary coral, and then lithologically correlated with marine and continental deposits elsewhere around coastal Cyprus. Shallow-marine deposits that can be broadly correlated with the F3 fluvial deposits in southern Cyprus have been dated at c. 185–192 ka, generally corresponding to MIS 7 (Poole et al. Reference Poole, Shimmield and Robertson1990), of later Mid-Pleistocene age. Comparable marine terraces in the Kyrenia range, N Cyprus, have recently yielded more accurate ages of 243 and 131 ka (Palamakumbura et al. Reference Palamakumbura, Robertson, Kinnaird and Sanderson2016a), also within the age span of MIS 7. MIS 7 lasted for c. >500 ka, with at least two main internal excursions, implying >60 m of eustatic sea-level change within this time interval (Cohen et al., Reference Cohen, Finney, Gibbard and Fan2013), with pronounced geomorphological and depositional effects.

In many coastal areas, MIS 7 marine terraces are covered by a veneer (commonly tens of centimetres thick) of shallow-marine carbonate rock (Poole & Robertson, Reference Poole, Robertson, Panayides, Xenophontos and Malpas2000; Palamakumbura & Robertson, Reference Palamakumbura, Robertson, Kinnaird, Van Calstern, Kroon and Tait2016b). These littoral deposits are dated generally at c. 116–130 ka and correlated with MIS 5e; i.e. related to the Last Interglacial (∼129–116 ka) when sea levels are inferred to have been c. 6 m above modern day in many areas (Horton et al. Reference Horton, Kopp, Garner, Hay, Khan, Roy and Shaw2018). MIS 5 lasted for >350 ka, with several high-frequency oscillations (Cohen & Gibbard, 2010), which are again likely to be represented by small-scale geomorphological and depositional changes. For example, on the island of Mallorca (Spain), MIS 5e was associated with coastal erosion and eustatic sea-level rise (Rose et al. Reference Rose, Meng and Watson1999). Comparable coastal erosion is seen around Cyprus, notably in the Larnaca area (Poole & Robertson, Reference Poole, Robertson, Panayides, Xenophontos and Malpas2000).

The long-lived, strongly fluctuating MIS 7 highstand (later Middle Pleistocene) facilitated extensive downcutting to form wide coastal terraces, as best developed in SW Cyprus (Poole & Robertson, Reference Poole and Robertson1991). The associated deep incision gave rise to a broad (but variable) valley and the accommodation space necessary for a wide range of clastic sediments, palaeosols and colluvium, as observed throughout the Vasilikos river catchment. The similarly long-lived MIS 5 highstand (Middle–Late Pleistocene boundary) was followed by incision of the narrow, steep-sided slot into the ophiolitic bedrock in the upper reaches and erosion of the broad shallow valley in the lower reaches (south of Kalavasos). In general, aggradation is likely to have occurred following strong incision, mainly during periods of high eustatic sea level (interglacials), as also inferred for the NE Troodos Akaki river catchment (Main et al. Reference Main, Roberston and Palamakumbura2016).

Charcoal from the palaeosol in the lower part of the colluvium (harvara) at Kalavasós Márcou which overlies the F3 erosion surface yielded a radiocarbon age of 31 970 ± 910 a BP (Schirmer, Reference Schirmer1998) and an OSL age estimate of 29.82 ± 2.11 ka (Kinnaird et al. Reference Kinnaird, Robertson, Robertson, Parlak and Ünlügenç2013). Charcoal from a brown-grey discontinuous parting higher up (‘charcoal streak’) in this section yielded an age of 27.44 ± 1.6 ka (Schirmer, Reference Schirmer1998). Palaeosol from the lower part of a succession (c. 8 m thick) of alternating palaeosols and harvara in another section, c. 1.2 km north of Kalavasos, gave an OSL age estimate of 9.97 ± 2.08 ka (Kinnaird et al. Reference Kinnaird, Robertson, Robertson, Parlak and Ünlügenç2013). In addition, a sample from another section, which is located c. 200 m further WNW (Vasilikos–Drapia), gave a significantly older age of 66.40 ± 4.07 ka. The sample was collected 2 m above the modern channel bed and at a slightly lower level than the younger sample.

The Kalavasós Márkou harvara is similar to the widely distributed colluvium overlying the F3 surface (e.g. N of Kalavasos) which is therefore likely to be mainly late Pleistocene. However, the available stratigraphic and age evidence suggests that that harvara formed cyclically throughout the Pleistocene. The dated palaeosols also formed at different times (>65 ka to <10 ka), at different levels of the valley slopes, especially above the F3 and/or F4 erosion surfaces. The Eastern Mediterranean experienced relatively wet conditions during c. 6000–5400 BP, followed by drier conditions with short-lived more humid periods until the present day (Finné et al. Reference Finné, Holmgren, Sundqvist, Weiberg and Lindblom2011). Comparable results from SW Cyprus (Dhiarizos River) suggest that incision and subsequent alluvial aggradation took place synchronously in Cyprus over the last 2000 ka (Deckers, Reference Deckers2005) and also elsewhere in the Mediterranean (Macklin et al. Reference Macklin, Fuller, Lewin, Maas, Passmore, Rose, Woodward, Black, Hamlin and Rowan2002).

5.l. Influence of neotectonic deformation

Did neotectonic faulting play a significant role in Vasilikos Valley geomorphology and sedimentation?

North of Kalavasos, the colluvium above the F3 surface exposes a local angular discordance which is likely to reflect contemporaneous fault-related tilting, followed by progradation of further colluvium (sub-horizontal) (Fig. 15f). The fault-modified palaeotopography in this area affected erosion and sediment deposition locally. However, there is little evidence that neotectonic faulting has had a significant regional influence on sediment supply or geomorphology in the Vasilikos river catchment, where instead the development is similar to the periphery of the Troodos Massif as a whole. Most other faults deform units up to and including the Messinian deposits. Some faults in the area appear to have been reactivated in response to NW–SE compression, associated with c. E–W left-lateral strike-slip during Pleistocene–Recent time. Such transpressional effects can be broadly related to the westward tectonic escape of Cyprus from the colliding African and Eurasian plates (Soulas, Reference Soulas, Petrides, Chrysostomou, Kyrou and Hadjigeorgiou2002; Harrison et al. Reference Harrison, Newell, Batıhanlı, Panayides, McGeehin, Mahan, Ozhur, Tsiolakis and Necdet2004; Kinnaird & Robertson, Reference Kinnaird, Robertson, Robertson, Parlak and Ünlügenç2013). However, there is no known structural evidence of major vertical fault offset which could have significantly affected the overall relative chronology of geomorphic terraces and deposits, including those in Vasilikos Quarry.

5.m. Wider implications

Much Quaternary research focuses on trying to identify and isolate specific features (e.g. fluvial deposits; geomorphological slopes) that can then be studied in terms of the processes involved, quantitatively where possible (e.g. stream power, mass flow). However, there is also considerable merit in detailed case histories through time where every geomorphic surface and deposit has its place, allowing detailed comparisons of the processes involved. Global survey of such processes indicates a preference for climatic-related explanations, representing 55 % of documented examples compared to tectonic-related explanations that make up only 5 % (Schanz et al. Reference Schanz, Montgomery, Collins and Duvall2018). In this regard, the Vasilikos river catchment is firmly in the ‘camp’ of a dominantly tectonic control at least during the Early–Middle Pleistocene when most of the geomorphological surfaces and sediments discussed here were formed. However, the processes of tectonic uplift (including timing and rate), climate (and climatic change) and eustatic sea-level change (especially in near-coastal areas) go hand-in-hand and interact to produce the landscape and deposits. The Vasilikos river catchment has the potential to emerge as a classic open-air laboratory for a wide range of related processes, especially if more accurate dating becomes possible in the future.