Geological framework

From south to north the Southern Italy is subdivided into the following morphotectonic belts: (1) The northern Calabrian Arc, including ophiolites, crystalline basement rocks and Mesozoic sedimentary sequences; (2) the Cilento and Calabro-Lucanian Ranges, having ophiolitic, metasedimentary and sedimentary rocks. The Ranges include a Paleogene Subduction Complex (the Calabro-Lucanian Flysch Unit or Liguride Complex of southern Italy), the middle Miocene foreland strata of the Cilento Group and younger sequences, and the Mesozoic to Miocene carbonate platform and slope (inner platform or Alburni-Cervati-Pollino Units and the Monti della Maddalena Unit); (3) the Campano-Lucanian Ranges, including Mesozoic to upper Miocene deep-sea sequences of the Lagonegro and Sicilide units, the outer platform sequences (Monte Alpi Unit), and the Miocene foreland strata; (4) the Lucanian-Apulia lowland, including the Pliocene to Quaternary foreland clastics; and (5) the Apulian Swell, a Mesozoic to Quaternary carbonate platform (external platform).

The Apennines constitute part of the main mountain system of the Mediterranean region (Fig. 1). The chain evolved within the framework of the convergent motion between the African and European plates and related microplates since Late Cretaceous time (Mazzoli & Helman, 1994; Critelli, 1999; and references therein). They are formed by a fold and thrust belt–foredeep system that records east-thrust transport directions and accompanied by the development and deformation of progressively younger turbiditic deposits to the east. These features indicate tectonic accretion due to a westward dipping subduction slab since at least Oligo-
Miocene time. As a result, the back-arc development of the Western Mediterranean basins (e.g. Algero-Provencal and Tyrrhenian Basins) are linked to the eastward rollback of the Adriatic slab (Fig 1).

The early configuration of the subduction system (Late Cretaceous– Oligocene interval) is still a matter of debate, particularly for the segment of chain between the southern Apennines and the Sicilian Maghrebids, commonly known as Calabria– Peloritani Arc, where crystalline basement and ophiolitic nappes crop out (Fig. 1). Since Late Oligocene-Early Miocene time convergence occurred between the Corsica–Sardinia–Calabria block, to the west, and the Apulia (or Adria) block, of African affinity, to the east (Fig. 2). The subduction and collision produced the structure of belt characterized by an imbricate thrust system propagating towards the foreland and accompanied by several syntectonic sedimentary successions (Figs.3-4).

Figure 2 - Palinspastic restoration of the Central Mediterranean region in the late Oligocene (about 30 Ma) showing the distribution of the Central and Southern Apennine platforms and basins before their incorporation in the mountain chain. 1) European foreland. 2) Paleogene mountain chains. 3-6) African foreland: 3) shallow-water carbonate platforms; 4) deeper-water basins floored by oceanic or thinned continental crust; 5) basinal areas with isolated structural highs; 6) wide pelagic plateau; 7) fronts of the orogenic belt, (from Patacca & Scandone, 2007).

Figure 3 - Schematic representation of the geometric relationships between the tectonic units of the southern Apennines (from
Patacca & Scandone, 2007).

At the boundaries of northern Calabria and southern Basilicata, the Meso-Cenozoic carbonate successions of the Apennines are in contact with the crystalline Calabrian

Arc (Fig. 1). According some Authors, the stratigraphic and structural lineaments of the Pollino area showed the occurence of three main imbricate carbonate units; from bottom to top, they are:
-the metamorphic "S. Donato Unit", which consists of a lower terrigenous interval

(Werfen facies with organogenic carbonate, buildups, Early Triassic-Permian in age) and an upper carbonatic interval to which a genetic Triassic age could be assigned; - the "Carbonate Platform Unit" formed by two tectonic subunits both ranging from Triassic to Eocene (Verbicaro and Pollino Units). These two elements are mainly constituted of neritic carbonate and of eteropic pelagic deposits which show the same kinematic evolution.
In the northern part of this region, three main groups of nappes may be distinguished: (1) crystalline basement nappes (Calabride Complex in Fig. 5 ); (2) ophiolite-bearing nappes (Liguride Complex in Fig. 5); (3) mostly calcareous nappes (Panormide Complex in Fig. 5) derived from the inner part of the Apulia continental margin. Group (1) includes Hercynian metamorphic and crystalline rocks and Mesozoic deposits of the Sila Unit. These Paleozoic units overlie ophiolite-bearing units, ranging from greenschist- facies (Malvito Unit), showing in some cases (Reventino– Gimigliano Unit) evidence of an earlier HP–LT metamorphic event, to blueschist-facies metamorphism (Diamante–Terranova Unit). Some of these units, the HP–VLT (very low temperature) Frido Unit and the unmetamorphosed Calabro- Lucanian Flysch Unit. The latter crop out NE of the Pollino Massif, in Calabria– Lucania border area (Figs. 4-5). This metasedimentary or sedimentary cover includes the uppermost Oligocene and Aquitanian units, respectively.

Liguride Complex

The Liguride Complex is composed of two ophiolite-bearing units, overlain by thick turbiditic sequences (Fig. 5), considered as a remnant of a Late Cretaceous-Miocene accretionary wedge. The lowermost unit is made up of un-metamorphosed terranes (the Calabro-Lucano Flysch Unit), Late Jurassic-Late Oligocene in age, showing “broken formation” characters. This unit is ovelain by metamorpic sequences (the Frido Unit) made up of prevailing shales and calcschists including blocks of ophiolites and crystalline blocks. These terranes show a Late Oligocene HP/LT followed by green schist facies metamorphism. The ophiolite-bearing units are unconformably covered by turbiditic synorogenic sequences (Saraceno fm and Cilento group),
representing perched basin deposits (Fig. 5).

Figure 4 - Geodynamic and regional geological framework of southern Italy (from Mazzoli et al., 2000; Iannace et al., 2007)

Figure 5 - Tectono-stratigraphic representation of the northern Calabria and Southern Apennines (Pollino Massif) mountain belts (from Critelli, 1993).

Carbonate Units

Recently the Iannace et alii (2005; 2007) grouped the Meso-Cenozoic sedimentary– metasedimentary successions into three tectonic units: the Lungro–Verbicaro Unit, the Pollino–Ciagola Unit and the Cetraro Unit. The Pollino–Ciagola Unit is tectonically overlain by ophiolitic units in the northeastern part of the Pollino Massif, whereas toward the NW it is overlain by the Lungro– Verbicaro Unit (Fig. 6). The Cetraro Unit is tectonically overlain by the Lungro–Verbicaro Unit and both are tectonically overlain by ophiolitic and continental crust-derived units (Calabride Complex). The tectonic contacts between the latter units are sealed, in the western margin, by Serravallian–Messinian sequences (Fig. 6) and by Pliocene and Pleistocene sediments.

Figure 6 - Structural map, geological sections and stratigraphic-tectonic sketch of northern Calabria. Key to the stratigraphic- tectonic sketch. 1a: Middle Triassic phyllites; 1b: carbonate intercalations; 2a: Ladinian–Carnian meta-limestones; 2a: Carbonate build-ups of Monte Caramolo; 3a: phyllites, carbonates and evaporites of Cetraro; 3b: Carnian dolomites; 4: Norian–Rhaetian dolomites, carbonatic conglomerates, limestones and marls; 5: Jurassic cherty limestones and radiolarites; 6: Upper Cretaceous–Aquitanian Colle Trodo formation; 7: Lower Burdigalian siliciclastic deposits (Scisti del Fiume Lao); 8: Norian–Rhaetian platform dolomites; 9: Jurassic platform limestones; 10: Cretaceous platform limestones; 11: Jurassic–Palaeogene carbonatic conglomerates;14: Langhian Bifurto Formation; α: Triassic basic volcanics; β: Jurassic–Cretaceous basic volcanics (limburgites), (from Iannace et al.,2007).

Lungro–Verbicaro Unit

The stratigraphic succession of the Lungro–Verbicaro Unit, affected by HP–LT metamorphism, consists in its lowermost part of Middle Triassic phyllites and metarenites with carbonate intercalations (Fig. 6). The latter contain locally rich assemblages of strongly recrystallized dasycladacean algae of Anisian and Early Ladinian age, suggesting a shallow water origin. These deposits are followed by Ladinian–Carnian metalimestones, marly metalimestones and dolomites, with local build-ups rich in dasycladales, crinoids and spongiomorphids and a well-developed reef complex in the area of Monte Caramolo. One of the most characteristic facies is represented by dark marly metalimestones with abundant burrows and thin bivalve- and gastropod-rich beds. The early siliciclastics input pass upwards to a mixed carbonate and siliciclastic input, such a shelf being bordered by sponge and cement- rich buildups (Iannace et al., 2005).

In the Carnian layers there is a significant increase of siliciclastic beds intercalatedwith metadolomites, metalimestones and evaporites. Siliciclastic and evaporate strata prevail to the SW, whereas to the NE the succession is dominated by metadolomites. This succession is followed by several hundred metres of metadolomites referable to the Norian– Rhaetian, showing sudden lateral facies changes. Within a few kilometres, inner platform facies pass to marginal build-ups, consisting of an unusual assemblage dominated by microbes and serpulids and small calcareous sponges, and then to slope and restricted basin facies (Iannace et al.,2007).

Figure 7 - Representative geological section and stratigraphic columns of the LVU and PCU, (from Iannace et al., 2007).

The Jurassic is mostly represented by a cherty metalimestone succession (Cherty limestone Fm) of variable thickness, which can be found either in stratigraphic continuity with the metadolomites or locally above an angular unconformity. The metalimestones are generally coarse and crystalline; and locally exibit turbiditic strata. On top of this lithological interval, dated by the authors to the Early Lias– Late Dogger, are locally preserved (Monte Cerviero, Verbicaro, Cirella) red siliceous slates and radiolarite beds. The overlying Colle Trodo Fm, rests disconformably on the older formations. Its base consists of coarse carbonate conglomerates and brecce of Maastrichtian–Palaeocene age. The rudites are followed abruptly by red and green metapelites with frequent beds of calcareous turbidites grading upward to yellowish metamarls of Middle Eocene to Aquitanian age. The Colle Trodo Fm grades upward to metapelites and metarenites containing some calcarenite and calcirudite beds with microforaminifera of early Miocene age (Flysch of Lao river).
Metabasaltic lavas with pillow structures and dykes (‘limburgites’) cut across the Triassic and Jurassic formations of the unit and are locally capped by the siliceous slates and radiolarites (Fig. 6).

{slider The Pollino–Ciagola Unit}

The main outcrops of the Pollino–Ciagola Unit are located on the Ciagola–Gada ridge, and around the villages of Papasidero, Aieta, Maratea and Campotenese, and comprise carbonate slope facies deposits. Large and variable stratigraphic gaps occur in these slope facies successions, which were considered as the lateral equivalent of the platform succession cropping out in the Pollino Massif. The Late Triassic is almost everywhere represented by thick bedded, white to light grey dolomites. Laminated, fenestral facies generally alternate with bivalve- and gastropod-rich beds, indicating sedimentation in peritidal, low-energy environments. The fossil content (gastropods, foraminifers and algae) is typical of the Norian–Rhaetian. The dolomites grade upward to limestones with megalodontid shells, tens of centimetres in size, of latest Norian– Early Rhaetian age. In the Jurassic, a marked facies differentiation becomes apparent between the eastern and western outcrop areas. In the former, calcareous wackestones and packstones with Foraminifera, algae, ooids and oncoids are dominant, indicating a persistent shallow-water, lagoonal environment. As such, these successions are comparable with those of the Monte Pollino area. In contrast, resedimented, calcareous facies are dominant at Monte La Serra, Monte Ciagola and Aieta, indicating a lateral transition to a slope domain. The most complete succession is that of Monte La Serra, where the upper Triassic megalodontid limestones are replaced upward by mud-supported calcareous conglomerates rich in coral, gastropods, sponges and echinid fragments. The Jurassic age is confirmed in the lower part of the interval by the presence of Stylothalamia sp. At Monte Ciagola the conglomerates contain a marly, yellowish matrix and are generally strained.

A comparable facies distribution is recorded also in Cretaceous rocks, with the eastern area dominated by shallow-water facies and the western area mainly occupied by resedimented slope deposits. The former are represented by dark, well- bedded, generally cyclic limestones with characteristic shelf macrofossils of this age (requienids, radiolitids, hippuritids) and a rich assemblage of microforaminifera and algae. These resedimented deposits comprise graded coarse calcarenites, floatstones and rudstones with abundant bioclasts of marginal environments (rudists, gastropods, corals, echinoderms). The resedimented facies are more abundant in the upper part of the succession.
In the Pollino Massif the Cretaceous shallow-water rudistid limestones are disconformably covered by the brackish lagoonal to shallow marine Trentinara Fm (Fig. 7), followed by middle Aquitanian–lower Burdigalian open shelf calcarenites (Cerchiara Fm), and by siliciclastic turbiditic deposits that are not older than Langhian, which include ‘Numidian’ quartzarenites of the Bifurto Fm (Figs. 7-8).

Figure 8 - Paleogeographic reconstructions (Oligocene to early Miocene) of the western Mediterranean during progressive closure of the remnant ocean basin and onset of collision in southern Apennines (from Critelli, 1999; Critelli et al., 2011).

On the SE side of the Pollino massif the Cerchiara and Bifurto Fms directly overlie the Cretaceous limestones. In all other areas, instead, the Cretaceous shallow-water carbonates are followed by coarse calcareous breccias. The occurrence of Nummulites sp., in both the clasts and the matrix, indicates that these beds are not older than Palaeogene. These breccias rapidly evolve to thin-bedded calcarenites that are also strongly deformed and contain, in the upper part of the succession, Myogipsina sp. and other Miocene Foraminifera. The succession is topped by marls, pelites and rare quartzarenite intercalations, which can be correlated with the Bifurto Fm (Iannace et al., 2005; 2007).

Tectonic remarks

The geology of Calabrian-Lucanian boundary suggests that the building up of this belt system is a continuous and progressive process through which basin and platform domains were accreted at the southern continental margin of Neotethys (Fig. 9).

Figure 9 – a) Simplified geological profile across the Calabria-Lucania borderland area of the southern Apennines-Pollino Massif. b) Schematic palaeogeographic setting of the Apulian continental margin in Cretaceous time, (from Cello & Mazzoli,1999).

The whole process developed in three main evolutionary stages that appear to be constrained by the large scale kinematics of the African and European plates (Monaco et al., 1998; Cello & Mazzoli, 1999; Mazzoli et al., 2000) . Each stage includes different deformation events that may be grouped into sequences of comparable time/scales. During Stage I an accretionary wedge developed in response to the north-dipping oceanic subduction of Neotethyan lithosphere underneath the northern continental margin. Stage II started with the obduction of the accretionary complex and continued with the earliest phases of accretion of the Apulian continental margin. During this stage the accretionary wedge overthrust the southern margin of Neotethys and deformation affected the westernmost domains of the continental margin. During Stage III deformation in the southern Apennines appears to be related to the opening of the Tyrrhenian basin and coeval accretion of the easternmost domains mostly by underplating, and to the deformation associated with strike-slip tectonics (Monaco, 1993). The latest event recognized in the area started in Early Pleistocene time, when distributed deformation of the foreland area occurred mostly by strike-slip faulting and associated positive and negative structures. As a result, the majority of the positive structures of the chain developed from the superposition of localized deformation associated with left- lateral strike-slip systems on preexisting structures which originated during the growth of the Apennine wedge. The activation of this late tectonic regime is also responsible for the severe dissection of the mountain belt into sectors displaying different subsurface crustal structures (Monaco, 1993). The major left lateral strike- slip faults may put into contact different portions of the Apennine wedge, with the spectacular development of structural high and pulled depressions.

Finally, the geological, stratigraphic, structural history of the entire Pollino Massif is the results of long term evolution of different and adjacent geological realm. In this context the chain, in all its stage of building, testifies the variety of rocks, geological structures, and morphotectonic lineaments that make it spectacular and varied.

The landscape of the Pollino National Park

Introduction

The Pollino National Park shows a complex and articulated stratigraphic and tectonic assemblage. It is formed by tectonic units made up of different types of rocks belonging to different age, origin and domains. The Pollino area shows a very uneven topography due to an alternation of morphostructural ridges and Quaternary tectonic depressions bounded by high-angle fault scarps. The area of the park faces both the Tyrrhenian coast of northern Calabria and the Ionian coast of Calabria and Basilicata, and include the medium and the upper reaches of the main river valleys of Calabria-Lucania boundary, i.e. Lao, Raganello and Sinni river valleys.
Three broad sets of geomorphic processes are principally responsible for landscape modelling and for carving the wide variety of landforms occurring in the Pollino Park: tectonics, river dissection, and karst processes. These geomorphic processes, combined with a high degree of geological diversity (structural frame and contrasting rock erodibility), give rise to a landscape alternating between steep mountainous districts and hilly areas.
In this regard, the Pollino Park features a wide range of landscapes and landforms that have long captivated some geoscientists. Here below, we describe the widest range of geomorphological features, with the aim of fascinating all readers about this wild and appealing landscape.

Geographical setting

This part of southern Apennines is characterized by an asymmetrical topographic profile. The summit line of the mountain belt is locally shifted toward the inner (i.e. Tyrrhenian) margin and does not correspond to the regional water divide. Consequently, the eastern flank of the chain has a greater length and a lower mean gradient than the western flank. The highest summits exceed 2000m a.s.l, whereas the mean elevation of the whole belt is about 650m asl. Many of the highest peaks offer wonderful panorama of the of Basilicata and Calabria landscapes.

In particural, the Pollino Ridge is a NW-SE trending morpho-structure made of Meso- Cenozoic carbonate rocks. It is classically interpreted as a simple homoclinal structure dipping to the NE under ophiolitic nappes which were emplaced in early Miocene time. The Pollino ridge is bordered by Quaternary basins filled by both marine and continental sediments.

Because of its geographic position and its mountainous nature, the Pollino National Park records a high climatic variability. The climate is Mediterranean with montane modifications (wetter summers and colder winters, with more than one month of snow cover). There is a strong precipitation gradient ranging from 300 mm to 1,500
mm. However, based on the analysis of daily and monthly rainfall concentration, the eastern side presents a greater seasonality of rainfall distribution, with high- intensity, short-duration thunderstorms (maximum daily rain up to 120 mm) strongly affecting the total yearly rainfall volume.

Geological control on processes and landforms

The landscape of the Pollino National Park is strongly controlled by lithology and structure, as well as by the intense uplift occurred during the Quaternary. This area lies in one of the most geodinamically active sectors of the central Mediterranean area, where complex crustal deformation is occurring as a result of the Africa- Europe collision, still active.

The core of the massif consists of Meso-Cenozoic carbonate units and Mesozoic Ophiolitic units covered by Neogene foredeep and late Miocene to Quaternary wedge-top basin clastics.

The formation of the Pollino landscape took place mainly during Quaternary time, strongly influenced by the tectonic history together with the action of geomorphic processes resulting from the main climate variations.

The main geomorphological units that can be recognized in the area are as follows:

• Carbonate mountainous massifs, with karst landscapes, bounded by deep structural slopes and some wide piedmont areas; these massifs host major cave systems and are important water storage zones.

• Terrigenous mountainous massifs, with jagged crests and deeply incised ravines.

• Marly-clayey hills, with gentle slopes and a dendritic drainage pattern.

• Intermontane basins and alluvial plains.

Tectonic and Structural Landforms

The imprint of tectonics on geomorphology of the Pollino is evident not only in the size, extent, and location of landforms, but also in the steepness of river profiles, the feature of mountain slopes, and in the pattern of river network.

Tectonics influences geomorphological processes and landforms through the direct action of faulting and the indirect influences of spatial variability in rock erodibility, and the effects of geological structure. Notably, the present landscape of the south- western slope of the Pollino Ridge is strongly related to tectonic activity, whereas structurally controlled erosional features dominate the north-eastern side. In addition, the different landscapes are due to the competing influence of bedrock on both sides of the Pollino Ridge.

The most impressive tectonic feature of the region is represented by the Pollino fault zone, which forms a NW-striking normal fault belt that runs more or less continuously along the Calabria-Lucania boundary continuing towards the SE in the Calabrian offshore. Some segments of the fault systems are still active, making the area a key point for characterising the seismic hazard of northern Calabria.

The fault belt is made up of some segments showing an overall en-echelon arrangement and formed by southwest-facing normal fault segments that strongly articulate the Pollino Ridge.

These fault segments exhibit very sharp rectilinear escarpments, locally showing well developed triangular facets separated by wineglass canyons. They are tens to hundreds of metres in height and noticeable from the A3 Highway, state roads (Fig.10) and many panoramic viewpoints.

Fig. 10. Highway A3 (Salerno-Reggio Calabria); view from the north of NW-trending Pollino fault scarp hanging relics of the gently rolling landscape.

Moving to the northeast, several pieces of evidence highlight the key role of lithological controls, through which geological structure receives its topographic expression. Conversely, it is hard to discern a clear topographic signature of tectonic landforms because of high rates of erosional processes. Nevertheless, through the indirect influences of spatial variability in erodibility generated by faulting and juxtaposition of rocks with variable erosion resistance, the influence of faults on landscape is easy to detect (fault line scarp, Fig. 11).

Fig. 11. Timpa San Lorenzo homoclinal ridge. Worthy to note are the fault line scarp (blue arrows) bordering the southwestern slope of Timpa San Lorenzo, and the T. Raganello gorge (red arrow) noticeable in the upper reach

Because of lithological heterogeneity, a diverse gallery of homoclinal ridge eroded onto Meso-Cenozoic carbonates is evident (Fig. 11). Notably, the Neogene sedimentary succession is strongly characterized by small-scale landforms (hogback and stepped slope) which develop according to the dip of the beds.

Fluvial processes and landforms

Fluvial processes and landforms reflect the morphology of highlands, major slopes and piedmont zone. Moving from the Pollino highland, streams change dramatically becoming roaring torrents excavating deep gorges and canyons with riverbeds excavated on bare rock or locally lined with very coarse-grained, lag deposits.

Anomalous drainage bucks structural controls, flowing across geological and topographic units. A common anomalous pattern occurs where a major stream flows across a mountain range. Such transverse drainage has prompted a variety of hypotheses: diversion, capture or piracy, antecedence, and superimposition.

In particular, superimposed drainage develops when a drainage network established on one geological formation cuts down to, and is inherited by, a lower and harder geological formation. The superimposed pattern may be discordant with the structure of the formation upon which it is impressed. Lao (Fig. 12) and Raganello (Fig. 11) gorges are considered two example of superimposed valley. Indeed, both rivers cut through the more erodible ophiolitic units and are held up by the harder, underlying limestone and dolostone. Furthermore, several pieces of evidence highlight the key role of river piracy that occurred during the erosive exhumation of the carbonate heights. River capture phenomena resulted from headward retreat of river valleys facing the sea, also favoured by coastal uplift, and by selective dismantling of highly erodible material overlying carbonate rocks.

Fig. 12. Overview of Tectonic and fluvial landscapes noticeable in the Pollino National Park. View from the south of Mt. Gada-Mt. Rossino ridge.

Intramontane-valley fans are uncommon, but piedmont fans are very widespread throughout the Pollino southern slope, and show no evidence of current activity.

Stepped landscapes

Since the Pliocene, contractional structures have been superimposed by extensional faults, which have fragmented the Calabria region into structural highs and subsiding basins. Since the Early-Middle Pleistocene, Apennine experienced strong uplift, largely coeval with motion on extensional faults.

It is worthy to emphasise that above the fault scarps produced by these fault belt crossing the chain, the landscape is dominated by hanging remnants of gentle land surfaces, which locally form a staircases up to 2100m a.s.l. These land surfaces can be related to the oldest stages of landscape evolution occurred during Early-Middle Pleistocene through relief smoothing erosional and depositional processes.

In this regard, the Mercure and Castrovillari basins (Fig. 13) provide the best evidences of these step-like distributed surfaces very useful to reconstruct the main
stages of landscape evolution during the Quaternary.

Fig. 13. (A) Morphostructural sketch map and morphostratigraphic section of the Mercure intramontane basin showing the main recognized tectonic landforms and the distribution of the palaeolandscapes.(B) Block diagram showing the main depositional stages, landscapes and landforms of the Castrovillari basin.

Karst landforms

The calcareous zone of the Pollino National Park is pivotal to explain how karst processes act within a carbonate massif and how they influence underground water storage and circulation In particular, the Pollino area may be considered one of the best example of a karst massif in Southern Italy. Notwithstanding the abundance carbonate massifs in southern Apennines (Matese Mts., Picentini Mts. and Alburno-Cervati Mts.), the Pollino massif preserves similar karstic environment (deep and large caves), variety (i.e. active and fossil phreatic caves, contact ponors, polje) and beauty.

For example, moving on to the karst plateau upward of Frascineto (Fig. 14), there are several evidences of surface karst landforms from where waters come in (e.g. ponors, blind valley) even though how underground water circulates inside a karst massif is still to be well understood.

Furthermore, many cave systems should be explored for research topics and to assess their potential interest in geo-tourism terms and to provide a valid example
for further geo-itinerary planning.

Fig. 14. (A) Sketch of karst plateau area, where ponors fed by a blind valley transport rainwater down to the basal water table through vertical cave systems; 1) blind valley, 2) ponor, 3) solution doline, 4) collapse sinkhole, 5) vertical cave system, 6) karst resurgence, 7) fossil phreatic cave, 8) basal spring, 9) active phreatic karst system. (B) The Timpone del Castello gently rolling landscape is widely characterized by surface karst landforms reported in (A); Red and blue arrows indicate part of the complex Deep Seated Gravitational Slope of Civita and the T. Raganello gorge, respectively.

This could give visitors hands-on experience of the fascinating underground world created by the waters during their path within a limestone massif.

It is noteworthy that many karst plateaus, locally constituting stepped landscape, are interpreted as border polje that developed through karst processes at the contact between limestones and erodible materials.

Glacial landforms

 The highest peaks of the Pollino Nationakl Park (Mt. Pollino, 2267 m; Mt La Mula,

1935m, Mt. Cozzo del Pellegrino, 1987) show clear traces of glaciers (Fig. 15). The glacial remains consist in some cirques and cirquelike forms, and in some morainic alignments dating from the LGM and their retreat phases During the LGM, on Mt. Pollino the equilibrium line altitude was 1800 m. One rock glacier has been also found on Mt. Pollino. It overlies the moraine of the early phases of glacial retreat, about 1750 m a.s.l; it is older than the stadial moraine covered by loess dated 15-16,000 years BP.

Fig. 15. Location of cirques and morainas on (A) Mt. Pollino, (B) Mt. Cozzo del Pellegrino, (C) Mt. La Mula

The majority of the rock glaciers were formed between 20,000 and 10,000 years BP, when the mean yearly temperatures were still 4–6 °C lower than the present ones; however, their geographic distribution gives rise to some important considerations.

The geographical distribution of the rock glaciers, corresponding to the boundary of the areas with mountain permafrost, suggests that, during the final phases of the LGM period, in the Late Glacial and in the early Holocene, there was also an altitude and latitude shift with a reduction of this boundary, following the temperature increase. From the altitude of 1570/1600 m, the boundary of discontinuous mountain permafrost rose to 2300/2500 m during the late Holocene, and it is now even higher. About the time of the latitude shift, the boundary migrated
northwards, from 39°55'N to 41°45'N and later to 42°07'N.

Cryoplanation terraces and pediments may also features, although their genesis and significance is still to be assessed. In fact, gently rolling landscapes may be also developed by different processes and at different rates as locally suggested by their non-glacial appearance and presumed long periods of formation.

{slide Slope processes and landforms}

Slope processes and landforms are widespread throughout the Pollino Massif, particularly where high erodibility lithologies crop out.

Sharp increase in slope gradients marks the transition to the downstream area, where deeply incised valleys originate, the thickness of regolith strongly decreases and slope movements becomes the dominant process. Landslides are widespread and intense, and form all-size scars, scree slopes and landslide-related fans. However, due to outcropping of more erodible rocks, the lucanian side is more deeply dissected and affected by deep-seated mass-movement. Literature data highlighted that factors favouring such morphogenetic attitude to mass-movement are the extremely pervasive and intense tectonic deformation of rocks along with clay content.

On calcareous bedrock, the main mass movement is the complex Deep Seated Gravitational Slope of Civita (Fig.5) whose development is strongly controlled by a fault zone. It reach relevant dimensions, being about 2-km wide with a maximum local relief exceeding 600 m.

On ophiolitic units and Neogene outcropping sedimentary rocks, landforms depend on the dominance of mass-movement or running-water modelling processes. Where flysch and clayey melange significantly outcrop, a wide range of landslides occurs among which earth slide and flow are the predominant phenomena, and may reach very large dimensions. Alternating weak and resistant lithologies also provides
fascinating landslide scenarios.

On silty marls and onto old landslide bodies, badlands also develop. It is noteworthy where strongly fractured Meso-Cenozoic limestones and dolostones with marly intercalations crop out (e.g. near Mormanno) ; rocky slopes are deeply incised by steep flanked V-shaped gullies, outlining a badland-like drainage network.

{slide Conclusions}

The Pollino National Park provides a wide range of rocks, geological environment and tectonic structures. The entire area exhibits a variety of landscape that result from the interaction of tectonic uplift, river dissection, rock erodibility, and slope processes, which giving rise to a landscape alternating between steep mountainous districts and hilly areas. At times, landscapes are arranged in such a beautiful, ever- changing scenario that some landscapes may be considered unique and incomparable geomorphological examples, making the Pollino National Park potentially one of the most significant earth science sites in South Italy and a valid example for geo-tourism.

Notwithstanding its ease to access, it would be desirable that the geological and geomorphological significance of Pollino improves in the future by attracting more and more scientists and people, which may enhance its importance as a training ground for research programmes and recreation activities in a wonderful scenery
overhanging the Tyrrhenian and Ionian seas.

References

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