Imp. Muto & GGEEOOMMOORRPPHHOOLLOOGGYY,, TTEECCTTOONNIICCSS AANNDD SSEEDDIIMMEENNTTOOLLOOGGYY OOFF LLAATTEE QQUUAATTEERRNNAARRYY FFAANNSS BBEETTWWEEEENN GGUUAARRDDIIAA PPIIEEMMOONNTTEESSEE AANNDD PPAAOOLLAA ((TTYYRRRRHHEENNIIAANN CCOOAASSTT OOFF CCAALLAABBRRIIAA,, SSOOUUTTHHEERRNN IITTAALLYY)) FFrraanncceessccoo MMuuttoo,, GGaaeettaannoo RRoobbuusstteellllii ((**)),, FFaabbiioo SSccaarrcciigglliiaa,, VViinncceennzzoo SSppiinnaa && SSaallvvaattoorree CCrriitteellllii Dipartimento di Scienze della Terra, Università della Calabria. (*) Corresponding Author, e-mail robustelli@unical.it ABSTRACT An integrated geomorphological, preliminary structural and sedimentological study has been carried out, in order to investigate the role of tectonic and geological setting on the Late Quaternary evolution of the landscape. The study area represents a portion of the onshore belt located on the eastern margin of the Tyrrhenian extensional basin (Coastal Range). This sector of Calabria consists of a thrust-pile (Calabrian Arc Auct.), including both metamorphic and non-metamorphic rocks. Structural analysis evidences four sets of major fault systems; they affect a monocline consisting of a complex folded morphostructure. The NNW-SSE trending faults are dip-slip and oblique extensional faults, as suggested by superimposition of the striations. The relative chronology suggests that the youngest kinematics is represented by right-lateral normal faults. The NE-trending faults are oblique nor- mal and dip-slip faults; the latter are compatible with the kinematics of the right-lateral NNW trend. Geomorphological analysis allows three generations of alluvial-fans to be distinguished; furthermore, valley-side perched alluvial terra- ces occur in the lower reaches of the valley descending from the Coastal Range. The three generations of alluvial fans are telescopical- ly arranged, and the apexes of the piedmont fans (1st generation) are entrenched in respect to perched alluvial terraces. The fans at issue derived from steep catchments, developed as consequent and/or subsequent river valleys debouching from the mountain front. The piedmont zone comprises the 1st generation of alluvial-fans, bordered to the West by a nearly N-S striking scarp commonly rea- ching up to 80 m in height to the South. The present-day coastal plain comprises the 2nd generation of alluvial-fans which lie upon and interfinger with Late Pleistocene coastal and eolian deposits; the latter sail the foot-zone scarp of piedmont fans. A tephra layer has been recognised within eolian deposits. On the basis of preliminary structural and morphotectonic data, the last tectonic phase responsible for the latest landscape fragmenta- tion, was probably characterised by a NW-SE trending extension direction. Moreover, morphometric measurements and pre-existing offshore data support the hypothesis that, since Middle-Late? Pleistocene time, weak tectonic subsidence, coupled with marine base level rise, constitute the main mechanisms promoting the creation of the accommodation space for fan aggradation. The Quaternary alluvium is characterised by a variety of coarse-grained facies coming to be regarded as alluvial-fan facies. In particu- lar, detailed facies analysis revealed the presence of 4 facies associations, mainly represented by debris flow, debris avalanche depo- sits and sheetflood facies; facies associations also allow different alluvial fan evolutionary stages to be outlined. In addition, the lithology of the bedrock outcropping within fan catchments, have been also identified as the main factors which played important roles in control- ling the different depositional processes and consequently facies assemblages. RIASSUNTO È stato condotto uno studio integrato di carattere geomorfologico, strutturale e sedimentologico al fine di investigare il ruolo svolto dalla tettonica e dall’assetto geologico sull’evoluzione tardo-quaternaria di una porzione della Catena Costiera. Essa rappresenta il margine orientale del bacino estensionale tirrenico. Questo settore della Calabria consiste in una struttura a falde (Arco Calabro Auct.), com- prendente rocce sia metamorfiche sia non metamorfiche. L’analisi strutturale evidenzia quattro principali sistemi di faglie, che interessano una complessa morfostruttura. Le faglie NNW-SSE presentano cinematismi di tipo diretto ed estensionali obliqui, come suggerisce la sovrapposizione delle strie sui piani di faglia. La loro cronologia relativa mostra che la cinematica più recente è rappresentata dalle faglie normali a componente destra. Le faglie NE-SW risultano normal trascorrenti e dirette; le ultime sono compatibili con la cinematica dei sistemi NNW-SSE a componente destra. L’analisi geomorfologica permette di distinguere tre generazioni di conoidi alluvionali. Inoltre, terrazzi fluviali sospesi si rinvengono inca- strati morfologicamente nelle porzioni più basse e più distali (verso la costa) delle valli che dissecano la Catena Costiera. Le due gene- razioni di conoidi sono incastrate a cannocchiale l’una nell’altra, e gli apici dei quelle di prima generazione si incastrano tra i lembi dei terrazzi sospesi. I bacini di drenaggio che alimentano i conoidi, derivanti da un sistema di corsi d’acqua conseguenti e/o susseguenti che sboccano dal fronte montuoso, sono piuttosto acclivi. La zona pedemontana comprende le conoidi di prima generazione ed è limi- tata ad ovest da una scarpata a direzione circa N-S che verso sud raggiunge anche gli 80 m di altezza. La piana costiera attuale com- prende le conoidi di seconda generazione, che si sovrappongono e si interdigitano con i depositi costieri ed eolici tardo-pleistocenici; questi ultimi, nei quali è intercalato un livello vulcanoclastico, suturano la scarpata che limita, verso mare, i conoidi della zona pede- montana. Sulla base di dati strutturali preliminari e morfotettonici è stato possibile individuare l’ultima fase tettonica responsabile della frammenta- zione del paesaggio nell’area indagata, caratterizzata probabilmente da una direzione di estensione NW-SE. Inoltre, la misura di alcuni parametri morfometrici e la rilettura di dati sismici relativi alla piattaforma continentale sommersa consentono di ipotizzare che, a partire dal Pleistocene Medio-Superiore?, una debole subsidenza, accompagnata dalla risalita eustatica del livello del mare, doveva costituire il principale meccanismo per la creazione dello spazio di accomodamento utile alla crescita dei conoidi. I depositi quaternari affioranti nell’area sono rappresentativi di sistemi deposizionali di conoide alluvionale. In particolare sono state distinte 4 associazioni di facies, tra cui le principali sono rappresentate da conglomerati massivi (debris-flow e debris-avalanche) e da depositi di lame di piena (sheetflood); le associazioni di facies hanno consentito, inoltre, di definire differenti stadi evolutivi nella crescita dei conoidi alluvionali. Inoltre, la litologia del substrato, sottesa ai vari bacini idrografici, rappresenta un’ulteriore fattore di controllo nello sviluppo dei differenti processi deposizionali. Key words: Geomorphology, tectonics, sedimentology, coastal alluvial-fans, Tyrrhenian coast, Calabria, southern Italy Parole chiave: Geomorfologia, tettonica, sedimentologia, conoidi alluvionali costieri, costa tirrenica, Calabria, Italia meridionale. Il Quaternario Italian Journal of Quaternary Sciences 1166(2), 2003, 217-229 218 F. Muto et al. 11.. IINNTTRROODDUUCCTTIIOONN The study area is located along the western coast of Calabria, on the eastern margin of the Tyrrhenian basin (Fig. 1A). This basin developed since late Tortonian times (Kastens et al., 1990) as back-arc basin of the Southern Apennine thrust and fold belts (Patacca & Scandone, 1989; Patacca et al., 1990). Since Middle- Late Pliocene the Tyrrhenian basin was affected by extensional tectonics, responsible for the formation of perityrrhenian depressions, such as the Paola slope basin (Barone et al., 1982; Fabbri et al., 1981; Rehault et al., 1987), and the uplift of the Coastal Range (Sorriso-Valvo & Sylvester, 1993). The Plio-Quaternary evolution of the Paola slope basin has been investigated in detail by analysis of offshore data (Barone et al., 1982; Gallignani, 1982; Argnani & Trincardi, 1988; 1993; Chiocci et al., 1989; Chiocci, 1995; Chiocci & Orlando 1995). Conversely, few studies have been carried out on the reconstruction of the onshore basin margin, due to the dearth of geomorphological and stratigraphical data. Robustelli et al. (2002) represent the first attempt to reconstruct a Middle-Late Pleistocene geomorphological evolution. Furthermore, the only available literature on the geomorphological features of the Coastal Range has focused on the assessment and estimation of uplift rates (Verstappen 1977; Carobene et al., 1986; Carobene, 1987; Carobene & Ferrini, 1993; Bordoni & Valensise, 1998) and of hillslope degradation processes (Sorriso- Valvo & Sylvester, 1993; Sorriso-Valvo et al., 1998). Quaternary continental and marine deposits asso- ciated with erosional landforms coexist in the study area. An integrated structural, stratigraphical and geo- morphological study has been carried out in order to reconstruct the Late Quaternary evolution, and to state the role of tectonic and geological setting which, cou- pled with eustacy (Robustelli et al., 2002), influenced alluvial fan development. These Authors have proposed a model of evolution, according to which Quaternary fan development was mainly related to phases of climate amelioration following glacial periods, but just before interglacial highstands were approached; progressively increasing moisture and temperatures allowed bio-che- mical rock degradation, and consequent increased run- off favoured removal of slope-waste materials, which promoted alluvial-fan development, mainly by gravity processes. Sea level highstand induced coastal erosion of fan toes, resulting in foreshortened longitudinal profi- les and fan dissection (e.g. Harvey et al., 1999); sedi- ment input was probably channelled away from subae- rial basins, enabling progradation over the shelf. The subsequent lowering of sea level promoted fan-trenches lowering and the progressive emergence and dissection of the Paola Basin shelf; products of slope degradation during glacial periods, probably, had to be conveyed from the mountain catchments to fill paleovalleys, detec- ted by means of seismic profiles analysis (Chiocci et alii, 1989; Chiocci, 1995; Chiocci & Orlando, 1995), thus disabling fan-development. Fig. 1 - A - Northwestern sector of the Calabrian Arc (after Tortorici et. al., 1982, modified) with the location of the study area; B - Geological sketch map of the study area. A - Settore nord-occidentale dell’Arco Calabro, (da Tortorici et al., 1982, modificato) ed ubicazione dell’area di studio; B - Carta geologi- ca dell’area di studio. 219Geomorphology, tectonics and sedimentology... 22.. GGEEOOLLOOGGIICCAALL SSEETTTTIINNGG The northwestern sector of the Calabrian chain consists of a flat-lying nappe (Calabrian Arc Auct.) which constitutes the morphostructural height of the Coastal Range (Fig. 1A); in particular it consists of high- grade metamorphic rocks of the Polia Copanello Unit, tectonically overlapping low-grade metamorphic rocks of the Castagna Unit and Bagni Formation (Amodio Morelli et al., 1976; Dietrich, 1976; Colonna & Compagnoni, 1982); these units overlapped the Ophiolitic Complex (Liguride Complex, Ogniben, 1973; Messina et al., 1981, Boullin, 1984; Knott, 1987; Dewey et al., 1989), and the Carbonatic Units (Amodio Morelli et al., 1976). Thrust-sheets were cut by four sets of major faults, the relative ages of which have been determined by Sylvester et al. (1987). In the study area, a Miocene sedimentary sequen- ce rests on the crystalline-metamorphic basement of the Coastal Range; it constitutes the sedimentary infilling of the correlative Amantea basin, dated to upper Tortonian by Di Nocera et al. (1974), outcropping to the South (Mattei et al., 2002; Muto & Perri, 2002). In the study area, the Miocene deposits consist (Fig. 1B) of two unconformable sequences. The first one is characteri- sed by conglomerates and sandstones, underlying the 2nd sequence constituted by yellow calcarenites and grey-blue clays; the latter have been recognised in boreholes along the coastline. This succession exhibits a general monoclinalic attitude, with a growing dip towards West. Late Quaternary continental deposits rest unconformably on the basement and the Miocene sedi- mentary sequence. The Coastal Range is a horst which started to uplift since Plio-Pleistocene time (Tortorici, 1982a; 1982b), and produced the progressive isolation of the Crati Valley from the Tyrrhenian Sea, accompanied by the formation of the Paola Basin. This basin extends along the N-S direction, on the west side of the study area, from the Sangineto zone to the Capo Vaticano zone. The Paola basin has an architecture controlled by extensional tectonic phases and contractional events (Canu & Trincardi, 1989); moreover, it exhibits a depo- center localised immediately behind the continental slope, and is characterised by high depositional gra- dients (Fabbri et al., 1981; Gallignani 1982; Barone et al., 1982; Finetti & Del Ben, 1986; Chiocci, 1995). 33.. PPRREELLIIMMIINNAARRYY SSTTRRUUCCTTUURRAALL AANNAALLYYSSIISS The northwestern sector of the Tyrrhenian margin is characterised by a complex structural arrangement which is limited by the Falconara fault zone (Turco et al., 1990) to the South and the Guardia Piemontese morphostructure to the North. The oldest structures are represented by thrust faults and by two generations of folds, with axes orien- ted roughly from NNW-SSE to NNE-SSW. These folds, which involve all the Tortonian deposits, are asymmetric and verging to the East. These structures are cut by transtensive fault systems, that represent the result of the latest tectonic phases related to the Tyrrhenian basin Quaternary spreading. Fault-slip data were collected in 8 measure- ment sites, for a total amount of 120 measures. Measurement sites were positioned in Miocene depo- sits, whereas Quaternary deposits do not display any signs of deformation. Nevertheless, Quaternary tecto- nics is clearly demonstrated by evidence of uplifted Tyrrhenian strandlines (sea caves at about 12 m a.s.l. located near to Cetraro, close to the North of the study area, Carobene et al., 1986; Carobene, 1987; Bordoni & Valensise, 1998), and by cross-cut relationships between marine terraced deposits and fault systems (TortoriciI et al., 2002); furthermore, from a geomorpho- logical point of view, the fact that remnants of perched alluvial terraces are not related to any present-day or past landform and are located close to the escarpment bounding the mountain front support the Quaternary tec- tonic activity. Literature data (Tortorici et al., 2002; Muto & Perri, 2002; Tortorici et al., 1995) were used to constrain the chronology and the stress field of the last fault activity. A strong fit exists between the orientation of the main meso-faults and macro-fault systems, plotted in Fig. 2 - Structural data collected in the Miocene deposits. A - Rose diagram of the main meso-faults collected; B - Rose diagram of the macro-fault systems mapped in the study area; C - Lower hemisphere stereographic projection of the NNW trending fault system with the latest kinematic indicators on the planes; D - Lower hemisphere stereographic projection of the NE trending fault system with the latest kinematic indicators on the planes; E, F - Lower hemisphere stereographic projection of the NW-SE and E-W trending fault systems. Dati strutturali rilevati nei depositi miocenici. A - Rose diagram relativo alle principali mesofaglie misurate. B - Rose diagram relativo alle macro strutture cartografate; C - Proiezione stereografica, emisfero inferiore, del sistema di mesofaglie NNW-SSE con gli ultimi indicatori cinematici rilevati sui piani; D - Proiezione stereografica, emisfero inferiore, del sistema di mesofaglie NE-SW con gli ultimi indicatori cinematici rilevati sui piani; E, F - Proiezione stereografica, emisfero infe- riore, del sistema di mesofaglie NW-SE e E-W. 220 rose diagrams (Figs. 2A and 2B), suggesting that fault slip data well clarify the last kinematics of macro-faults. The main system faults are NNW-, NE-, NW- and E-trending. The occurrence of overlapping kinematic indicators on the same fault plane, along with the pre- sence of different slip directions on fault planes having the same strike and dip, allow multiphase tectonics to be outlined. The latest fault kinematics is showed in Figs. 2C-F. In particular, fault slip data of the NE-tren- ding systems suggest that their kinematic chronology shifts from left-lateral normal to normal dip-slip faults. The NNW-trending system faults show dip-slip and obli- que normal movements; the superimposition of the stria- tions allows a relative chronology of their movement to be fixed, i.e. from dip-slip to right-lateral normal faults. The left lateral NE-trending faults system, compatible with the NNW-trending dip-slip system, is older than the latest phase of movement characterised by dip-slip NE- trending normal faults and relative NNW-trending right lateral normal faults. The E- and NW-trending fault system are oblique normal faults and are characterised by a kinematics which is locally superimposed to left strike-slip ones. The latest kinematic indicators are consistent with an ESE-WNW extension interpretation, which repre- sents the main mode of deformation of the Calabrian Arc since Middle Pleistocene times (e.g. Tortorici et al., 1995). 44.. GGEEOOMMOORRPPHHOOLLOOGGYY Quaternary deposits of the study area, represen- ting mainly marine and alluvial environments (Argnani & Trincardi, 1993; Sorriso-Valvo & Sylvester, 1993; Sorriso-Valvo et al., 1998; Robustelli et al., 2002), are hosted in a narrow coastal strip, which can be conside- red the onshore counterpart of the Paola Basin infilling. These deposits are limited inland by the Coastal Range, essentially evolved by slope replacement mechanisms and river dissection. As a consequence of this evolution the west-facing slope of this mountain ridge shows well- defined triangular facets as isolated remnants of the N-S trending fault scarp, partly dismantled. The hydrographic network formed as a response to the Coastal Range uplift, producing steep catchments debouching seaward from the mountain front, which led to the emplacement of three generations of alluvial fans. As a general rule the drainage pattern follows the main fault system (Sylvester et al., 1987; Sorriso-Valvo & Sylvester 1993) and shows several asymmetric valleys. Geomorphic evidence suggest that the E-W consequent streams were interrupted and deflected by NE- and N-S trending subsequent streams, at least in the northern sector of the study area. Some morphometric data of the main stream catchments have been calculated, such as the mean drainage basin slope (Ds) and the drainage basin area (Da), the sweep angle, As (sensu Viseras et al., 2003) and the mean slope (Fs) of the fans. From these data it can be observed that the source catch- ments of the major rivers are very steep: the mean slope of the drainage basins, in fact, ranges from 31.43 to 40.65%. On the contrary, the fans are gentler, with mean slopes approximately around 10-14% or lower, except in the case of the T. Laponte (Fs = 15.48%). On the basis of data provided by Robustelli et al. (2002), three generations of alluvial-fans, telescopically arranged, have been distinguished. From a geomorpho- logical point of view, the study area consists of different, narrow geomorphological zones, parallel to the coast and limited by approximately N-S trending scarps proba- bly not related to faults (Fig. 3). The piedmont zone comprises the 1st generation of alluvial-fans which are telescopically inset in respect to remnants of perched alluvial terraces (Fig. 4A), gently sloping seaward but apparently not related to any present-day or past landform, which hang in some of the main river valleys dissecting the Coastal Range. A nearly N-S striking scarp borders the piedmont zone; local remnants of eolian deposits, with continental fauna, are well preser- ved on the basal portion of the foot-zone scarp. Quite a similar stratigraphic situation characterises the piedmont zone of the central Coastal Range (Sorriso-Valvo & Sylvester, 1993), where sandy eolian deposits outcrop along the foot-zone scarp and underlie the youngest alluvial fans. Amino-acid racemization dating on Helix sp. fix the emplacement of eolian sands at about 70 kyr B.P. (Sorriso-Valvo, pers. comm.). Furthermore, they rest on buried gravel deposits that constitute the bulk on which post-eolian sedimentation took place, as inferred by boreholes data, and are commonly capped by thin layers of slope deposits produced by scarp retreat. Hence these eolian sands clearly postdate the 1st gene- ration of alluvial fans (Middle-Late? Pleistocene) and predate the 2nd one (Upper Pleistocene-Holocene) (Fig. 4B). The most recent alluvial-fans, Late Holocene to recent in age, develop close to the present-day coastli- ne, and are substantially inactive and subject to very sli- ght river dissection. They lie upon and are entrenched within Late Pleistocene–Holocene coastal deposits, con- sisting of beach sands and gravels as well as eolian sands (Fig. 3). The bulk of the piedmont zone, reaching an eleva- tion of about 130 m a.s.l., consists of the oldest genera- tion of coalescent alluvial-fans, which show a sweep angle 60°. A particular attention must be given to a huge fan developed at the mouth of T. Laponte, which is entrenched in – and partly rests on – the dissected T. Maddalena alluvial fan. From the geomorphic relation- ships between the two alluvial bodies, the Laponte fan is obviously younger. Although its drainage basin is not the widest (Da = 6.32 Km2), it is extremely large, with an As value close to a square angle and the feeder channel filled with great amounts of sediments (cf. Sorriso-Valvo et al., 1998), assuming a typical “mushroom” shape (Viseras et al., 2003) in plan view. In the sector between Valle Santa Maria and the T. Maddalena, at the toe of the piedmont zone, the lower and younger alluvial fans occur. Their sweep angles commonly vary from 30-40°, reaching higher values for the T. Mercaudo (60°) and the T. Trappeto (about 90°). The above mentioned eolian sands, which taper upslope the nearly N-S striking scarp bordering the piedmont zone, are quartzolithic in composition; they have abundant lithic grains, and mostly equal amounts of quartz and feldspar (Qm20 F18 Lt62). Feldspar is dominantly plagioclase. Aphanitic lithic fragments (Lm86 Lv0 Ls14) include abundant metamorphic lithic frag- ments, represented by phyllite, fine-grained schist and minor fine-grained gneiss and amphibolite; sedimentary F. Muto et al. 221 Fig. 3 Geomorphological sketch map of the study area. Schema geomorfologico dell’area di studio. Geomorphology, tectonics and sedimentology... 222 lithic fragments are subordinate and include micritic and sparitic limestone, dolostone and metalimestone lithic fragments. Coarse–grained rock fragments include plu- tonic (mostly granodiorite and minor granite) and gneiss rock fragments. The abundant metamorphic detritus is derived from the diverse tectonostratigraphic units of the Coastal Range, Bagni, Castagna and Polia Copanello Units (Amodio Morelli et al., 1976; Dietrich, 1976; Colonna & Compagnoni, 1982), whereas the sedimen- tary detritus is derived from Mesozoic to Miocene sedi- mentary strata of the San Donato and Verbicaro Units (Amodio Morelli et al., 1976) and the Miocene sedimen- tary successions (Di Nocera et al., 1974; Mattei et al., 2002; Muto & Perri, 2002). A fine-textured, greyish tephra layer, about 20 cm thick, is interbedded within their upper portion and con- sists of impure volcanoclastic sands. Volcanic detritus includes pumice fragments, having vitric texture, and sometimes including plagioclase, pyroxene and biotite crystals. Rare volcanic lithic fragments exhibiting micro- litic texture consist of particles having plagioclase, bioti- te and pyroxene microlithes, and a vitric groundmass. In addition to volcanic detritus, the sample contains various non-volcanic detritus, which includes single quartz and feldspars, metamorphic and carbonate lithic fragments, and coarse-grained plutonic rock fragments. Micrite and microsparite interstitial component constitu- tes matrix and early cement of the sample. 55.. AALLLLUUVVIIAALL--FFAANN SSTTRRAATTIIGGRRAAPPHHYY On the basis of geomorphic analysis, described in the previous section, the Quaternary alluvium consists of perched valley-side terraced deposits and alluvial fan deposits; the latter comprise two generations of alluvial fans, telescopically arranged. Alluvial-fan deposits are characterised by the dominance of conglomerates; fine- grained facies were not observed. The clast lithology sli- ghtly varies over the study area; dominant clasts include ophiolitic units, phyllites, gneiss, schists, granites and sedimentary rocks. Because of the dearth of exposures which affect valley-side terraced deposits, sedimentary facies analy- sis has concerned only alluvial-fan facies. In particular a number of stratigraphic sections have been measured in order to give the sedimentary logs of Fig. 4, because of the vertical cliffs which confine the piedmont zone allu- Fig. 4 - Overviews showing the morphologic relationships among the perched alluvial terraces, the mountain front and the piedmont alluvial fans (A) and between the piedmont and the coastal alluvial fans (B). Foto panoramiche che illustrano i rapporti tra i terrazzi fluviali sospesi ed il fronte montuoso ed i conoidi pedemontani (A), e tra i conoidi pedemontani e costieri (B). F. Muto et al. vial fan; therefore sections were obtained along river incision and road cuts and extend parallel to fan-slope up to 9 m in width, and are representative of the upper- most portion of alluvial fans. As far as coastal-plain alluvial fans are concerned, thanks to excavations for the foundation of buildings located in the middle portion of T. Trappeto coastal fan, the relative sedimentary log (Fig. 4) is given; unfortuna- tely no sections are available for T. Mercaudo and T. Maddalena Coastal fans, because of the lack of artificial and natural exposures, the latter owing to slight river dissection. The base of both generations of alluvial fans is not exposed; the maximum thickness, provided by well log data, is 45 m and 35-40 m for the coastal and piedmont alluvial deposits, respectively. According to Robustelli et al. (2002), the latest phases of fan development occurred during climate amelioration following glacial periods, when increasing moisture and temperatures, enabling bio-chemical rock degradation, and increasing run-off allow slope-waste materials to be removed, mainly by gravity and subordi- nately tractive processes. 55..11 FFAACCIIEESS AANNAALLYYSSIISS The Quaternary alluvium is characterised by a variety of coarse-grained lithofacies coming to be regar- ded as alluvial-fan facies. In particular detailed facies analysis revealed the presence of 5 sedimentary facies, discussed below, which are described on the basis of clast-size, bedding, sedimentary structures and shape of the units. Three sedimentary logs are given in Fig. 4; they are representative of the uppermost part of the T. Trappeto piedmont fan, T. Maddalena piedmont fan and T. Trappeto coastal fan. FFaacciieess 11 -- SSttrruuccttuurreelleessss,, ccoobbbbllee ttoo bboouullddeerr--ssiizzee ccoonngglloo-- mmeerraattee No good exposures of this facies occur in the study area; a number of very small outcrops occur along roads ascending T. Laponte alluvial-fan apex zone, and as subordinate facies alternating in T. Maddalena alluvial-fan deposits. The latter allows facies analysis to be made. This facies consists of massive, monomictic, matrix to clast supported conglomerates of cobble to boulder grade. Basal surfaces of these beds, up to 1.8 m thick, are sharp and display fairly erosional features. Matrix content is locally abundant; it consists of a mixtu- re ranging from silt to pebble, seemingly of the same composition as the largest clasts; the latter are angular to subangular in shape, and it is worth noting the pre- sence of shattered ones. Fabric is disorganized, althou- gh uncommon, crudely coarse-tail inverse grading occurs. FFaacciieess 22 -- SSttrruuccttuurreelleessss,, ccllaasstt--ssuuppppoorrtteedd ccoonngglloommeerraattee Massive, poorly sorted, sheet conglomerates com- prise this facies. Bed thickness varies between 0.4 and 1.2 m. Basal bedding contacts are sharp and slightly irregular, with relief of up to 0.15 m; scour surfaces may be observed, but they are very uncommon. The debris consists of pebble to cobble-size clasts, ranging from angular to subrounded in shape. Matrix in an unsorted mixture varying between silt and fine-grained pebble, and is rarely sufficiently abundant to support clasts. Fabric is disorganized, although the longest a-axes of some elongate clasts may be seen parallel to paleoflow and imbricated a(p), a(p)a(i). Grading is absent or basal inverse grading locally occurs. FFaacciieess 33 -- IInnvveerrsseellyy ggrraaddeedd,, ccllaasstt--ssuuppppoorrtteedd ccoonngglloommee-- rraattee Inversely graded, clast-supported, poorly to mode- rately sorted sheet conglomerates characterise this facies. Basal surfaces of the beds, up to 0.5 m in thick- ness, are sharp and non erosive. Pebble to cobble-size clasts comprise this facies, ranging from angular to subrounded in shape. Matrix, varying between sand to fine pebble, is never sufficiently abundant. Inverse-gra- ding is well developed; inverse to normal grading is uncommon (Fig. 5A). Clast fabric locally displays a pre- ferred a(p)a(i) clast orientation. FFaacciieess 44 –– HHoorriizzoonnttaallllyy,, ccrruuddeellyy ssttrraattiiffiieedd ccllaasstt--ssuuppppoorr-- tteedd ccoonngglloommeerraattee This facies is characterised by vertically alterna- ting couplets of clast-supported sheet conglomerates (Fig. 5B); beds of this facies, up to 0.4 m thick, have sharp, non erosive basal bedding contacts. The debris consists of subangular to subrouded pebble to cobble grade and pebble to pebbly granule gravels. The coarse gravel units, occasionally clast-thick, are massive and moderately sorted; crude normal gra- dind may occur. Imbrication, locally well developed, is variable, showing a(p)a(i) and a(t)b(i) fabric modes. The finer grained beds seem to be more extensive than the coarse grained ones; they are moderately to well sorted and no grading has been observed. Pebble- size clasts show a local a(t) b(i) fabric mode. Outsized clasts, of coarse pebble to fine cobble grade, are spar- sely present and their long axis are aligned both parallel and normal to bedding planes. FFaacciieess 55 –– LLeennttiiccuullaarr,, ccllaasstt--ssuuppppoorrtteedd ccoonngglloommeerraattee This facies rests on facies 2 and 3; it consists of moderately to well sorted, clast-supported, lenticular gravel units up to 0.2 m thick and varying between 0.6 and 1.1 m in width. Granule to fine pebble-size clasts comprise this facies. Grading is absent, although cru- dely normal grading locally occurs. Imbrication may be well developed, showing a(t)b(i) fabric mode. 55..22 IINNTTEERRPPRREETTAATTIIOONN AANNDD FFAACCIIEESS AASSSSOOCCIIAATTIIOONNSS Detailed facies analysis revealed the presence of five facies, the interpretation of which has been descri- bed accordingly as follows. Lateral and vertical facies associations, coarse-grained texture, disorganized fabric, together with geomorphic analysis suggest that the depositional events were of very high-energy and consistent with an alluvial-fan depositional system. FFaacciieess 11:: DDeebbrriiss--aavvaallaanncchhee ddeeppoossiittss The conglomerates of facies 1 are massive, mono- mictic, matrix to clast supported and cobble to boulder grade; these features suggest high-energy depositional events. Furthermore, the angular nature of the gravel cla- sts, locally shattered, their monomictic composition and their poor sorting are interpreted as deposition by debris- avalanche events (Sorriso-Valvo, 1988; Yarnold & 223Geomorphology, tectonics and sedimentology... Lombard, 1989; Yarnold, 1993; Blair & McPherson, 1994). This facies results from failure of a large fractured and weathered bedrock cliffs which, during downward fall was characterised by partial disintegration; in fact shattered boulders, but also very weathered angular cla- sts, may be observed. A clayey reddish-brown paleosol layer, with wavy upper and lower boundaries, rests on this facies asso- ciation (Robustelli et al., 2002). FFaacciieess 22:: DDeebbrriiss--ffllooww ddeeppoossiittss The massive, sheet-like, non erosive based, poorly sorted, clast-supported nature of this facies sug- gest that depositional events were of high-energy, i.e. unconfined debris-flow. According to Shultz (1984), this facies is interpreted as depositional evidence of pseudo- plastic debris flow; in particular these units may repre- sent the deposits of cohesionless debris-flow (Smith & Lowe, 1991; Sohn et al., 1999) dominated by frictional grain interactions in which clast collision is hampered, resulting in the lack of inverse grading and clast imbrica- tion. The local a(p)a(i) clast fabric indicates that brief or transient laminar shear affected debris flow (e.g. Nemec & Postma, 1993). Beds with coarse-tail basal inverse grading are indicative of non-shearing rigid plugs resting on the basal part of flows affected by intense laminar shear (Nemec & Postma, 1993; Johnson & Rodine, 1984; Sohn et al., 1999). FFaacciieess 33:: CCllaasstt--rriicchh ddeebbrriiss--ffllooww ddeeppoossiittss Facies 3 is interpreted as the deposits of high-con- centration flows. The low matrix content, the framework support, the a(p)a(i) clast imbrication and the upward coarsening trend are thought to be evidence of clast-rich debris flow (Shultz, 1984). Generally the above descri- bed features are consistent with deposition of unconfi- ned, cohesionless debris flows (Nemec & SteelL, 1984; Shultz, 1984; Smith, 1986; Smith & Lowe, 1991), and the inverse grading being representative of granular flows in which a dispersive pressure dominates during motion (Lowe, 1982; Todd, 1989; Sohn et al, 1999). This facies may also be interpreted as representative of very high sediment-concentration dispersions, such as hyperconcentrated flood-flows, i.e. dilution of debris flows (Pierson, 1980; Pierson & Scott, 1985; Ridgway & DeCelles, 1993; Smith & Lowe, 1991 among others). FFaacciieess 44:: SShheeeettfflloooodd ddeeppoossiittss The dominance of horizontally stratified conglome- rates, characterised by vertically alternating couplets of coarse and fine grained beds, indicates that high-energy tractional processes were involved. In particular, the tabular conglomerate sheets suggest that deposition was laterally extensive. As a whole this facies is inter- preted as being formed by deposition of unconfined sheetflood pulses well testified by the alternating cou- plets of different clast-size (e.g. Blair & McPherson, 1994). High-density flood-flow interpretations, in particu- lar hyperconcentrated flood flows (sensu Smith, 1986; Smith & Lowe, 1991), may also be suggested by the clast fabric, including the outsized ones within the finer- grained beds. FFaacciieess 55:: SSttrreeaamm--ffllooww ddeeppoossiittss Facies 5 is thought to be deposited by low-energy stream flow. Evidence for stream-flow processes include 224 Fig. 5 - Logs of the alluvial fan conglomerates. Numbers refer to lithofacies. Letters refer to facies associa- tions (see the text for details). Sezioni strati- grafiche dei c o n g l o m e r a t i alluvionali. Le lettere si riferi- scono alle litofa- cies. Le sigle si riferiscono alle associazioni di facies (si veda il testo per i detta- gli). F. Muto et al. framework-support, a(t)b(i) imbrication, sorting and the lenticular geometries of individual units. This facies is associated with beds of facies 2 and 3, on which it com- monly rests, and are representative of deposition in small channels that developed over fan-slope after debris-flow deposition; in particular these lenticular gra- vel beds are thought to be produced by fine-fraction win- nowing on the debris-flow by overland water flows (Blair & McPherson1994). FFaacciieess aassssoocciiaattiioonnss Lateral and vertical facies association, coarse- grained texture, disorganized fabric, together with geo- morphic analysis suggest that the depositional events were of very high-energy and consistent with an alluvial- fan depositional system. Four facies associations have been distinguished and discussed below. FFaacciieess aassssoocciiaattiioonn AA is restricted to the base of the upper portion of T. Maddalena piedmont fan and T. Laponte fan; the few and scattered road-cut sections and observations of the cliffs from a distance indicate that this facies association consists of vertically alterna- ting debris flow and, subordinately, debris avalanche deposits. Very uncommon beds of facies 5 may occur. FFaacciieess aassssoocciiaattiioonn BB characterised the upper por- tion of T. Maddalena piedmont fan. The most common facies is the massive, poorly sorted, clast-supported sheet conglomerates (Facies 2). Subordinate facies are represented by inversely graded conglomerates (Facies 3) and clast-supported, lenticular units (Facies 5) of gra- nule-pebble grade. FFaacciieess aassssoocciiaattiioonn CC constitutes the bulk of the upper portion of T. Trappeto piedmont fan. It consists of alternating debris flow (Facies 2, 3) and sheetflood (4) facies; lenticular units (Facies 5) produced by fine-frac- tion winnowing on the debris-flow are also common. FFaacciieess aassssoocciiaattiioonn DD is restricted to the upper por- tion of T. Trappeto coastal fan and consists of debris flow deposit (Facies 2) usually capped by conglomerate lenses of facies 5. Sheetflood facies are uncommon. This facies association, though analogous to facies association C, is characterised by a decrease in clast- size. For instance debris-flow deposits of pebble to cob- ble grade and pebble to fine cobble grade characterised T. Trappeto piedmont and coastal fan, respectively (Robustelli et al., 2002). 66.. DDIISSCCUUSSSSIIOONN AANNDD CCOONNCCLLUUSSIIOONN On the basis of all data collected by means of an integrated geomorphological, structural and sedimento- logical approach, interesting issues can be addressed to discuss the Late Quaternary fan evolution along the northwestern sector of the Coastal Range. A strong structural control of drainage pattern is highlighted. To the North of the study area stream direc- tions follow strikes and fold axes trends of the Miocene sedimentary cover. Moving southward the drainage network, although following faults pattern, is superimpo- sed over the fold limb of the Miocene succession. As resulting from structural and morphotectonic studies addressed to paleostress reconstruction in an area close to the South (Muto & Perri, 2002; Tortorici et al., 2002), the last tectonic phase was probably charac- terised by a NW-SE trending extension direction and was responsible for the creation and re-activation of NE- trending faults; furthermore, it caused the reactivation of the NNW-trending ones with right lateral transtensive kinematics. This tectonic phase can be ascribed to Middle-Late? Pleistocene on the basis of cross-cut rela- tionships between marine terraced deposits and fault systems (Tortorici et al., 2002); it could have been the cause of landscape fragmentation, by interrupting the continuity of a possible pre-existing coastal plain and producing valley-side perched alluvial terraces, as also testified by the lack of landforms related to the perched terraces (Figs. 3 and 7A). The following development of the 1st generation of alluvial fans tapered upslope the triangular facets and sealed the fault scarps (Fig. 7B) created by the previous block-faulting. Since that time fan development was mainly related to eustacy, as sug- gested by Robustelli et al. (2002) and briefly reported in Section 1. The bathymetric maps of the continental shelf 225 Fig. 6 Alluvial fan facies. A - Inverse grading sheet conglome- rates interpreted as pseudoplastic debris flow (see the text for details); B - Alternating couplets of sheetflood facies; a(p) fabric mode is well noticeable. Particolari delle facies che caratterizzano i conoidi alluvionali. A - Conglomerati a gradazione inversa interpretati come la depo- sizione ad opera di debris flow pseudoplastici; B - Alternanza di coppie di livelli conglomeratici a differente granulometria inter- pretati come depositi di lame di piena (sheetflood); risulta ben evidente la disposizione dell’asse maggiore dei clasti, parallela alla superficie di stratificazione (a(p)). Geomorphology, tectonics and sedimentology... (present seafloor isobaths; Argnani & Trincardi, 1988; Chiocci et al., 1989), as well as the maps reporting the reconstruction of the last glacial erosional surface and the total thickness of Holocene deposits provided by Chiocci et al. (1989) and Chiocci & Orlando (1995), show patterns of seafloor dip and slope scarps orienta- tion, which widely match with the strikes of the main fault system observed onshore, i.e. NE-, NNW-, NW- and E-trending faults - as the well-known Falconara fault (Turco et al., 1990) - it may suggest that the above men- tioned tectonic phase has lasted at least till late Upper Pleistocene. Moreover, offshore from Capo Bonifati (just a few kilometres northwest of the study area) and from Guardia Piemontese, sharp breaks in slope approxima- tely at depths of 75-90 m b.s.l. can be clearly recogni- sed. These scarps border offshore two flat surfaces, which Chiocci et al. (1989) simply interpret as erosional terraces related to sea-level stillstands. The complete lack of Late Pleistocene marine terraces in the study 226 Fig. 7 - Main stages of Late Quaternary morphotectonic evolution of the study area (see the text for details). Principali fasi dell’evoluzione morfotettonica tardo-quaternaria dell’area in esame (si veda il testo per i dettagli). F. Muto et al. area, which, on the contrary, developed during Pleistocene times and were tectonically uplifted to diffe- rent heights both in the northern and the southern sector of the Tyrrhenian coast of Calabria (Carobene & Dai Pra, 1990; Carobene & Ferrini, 1993; Tortorici et al., 2002) could be explained in two different ways: (i) the rates of sea-level rise and tectonic uplifts were substan- tially equal in the study area, so that the terraces never formed (Cinque et al., 1993); (ii) the terraces really did form indeed and were subsequently submerged for sub- sidence phenomena involving this onshore sector of the Paola Basin. In the latter case, it could be hypothesised that the flat surfaces, occurred on continental shelf and identified from seismic data, would tentatively be related to the above mentioned wave-cut marine platforms (buried by Holocene deposits), and be the submerged counterpart of the adjacent, raised Late Pleistocene terraces. What is more, the presence of huge bioherm structures, up to several tens of metres high, just close to the slope break of these flat morphologies (Chiocci et al., 1989) sup- ports this idea: in addition, encrusting marine organisms of this kind usually develop in limpid and relatively shal- low water (photic zone) and their relics often outcrop at the top of marine terraces of different ages all along the south Tyrrhenian Sea coast (e.g. Brancaccio et al., 1990; Carobene & Dai Pra, 1990; Iannace et al., 2001; Riccio et al., 2001; Scarciglia et al., 2003). Their extreme verti- cal extension could be related to their rapid growth upwards concurrently with the progressive land subsi- dence and relative sea-level rise, just to maintain their suitable life environment. Furthermore, the landward migration of Holocene depositional depocenters (Chiocci et al., 1989; Chiocci, 1994) and their location at the mouth of the major streams dissecting the Coastal Range and debouching along the west coast (Argnani & Trincardi, 1988; 1993), which clearly indicate a strong control by sediment input from continental feeding sour- ces, could have also been favoured by subsidence. Some parameters used in the morphometric analysis of alluvial fans (e.g. Viseras et al., 2003) may support this hypothesis; in fact weak tectonic subsiden- ce, coupled with marine base level rise, may constitute the main mechanisms promoting the creation of the accommodation space for fan aggradation. In fact, it is worth noting that to the North of the study area uplift rates are very low (0.05 mm/yr, Carobene et al., 1986; Bordoni & Valensise, 1998). In addition, Robustelli et al. (2002) already highlighted that important fan develop- ment occurred in the study area during transitions toward interglacial periods, characterised by climatic amelioration and significant sea-level rise. Both the peculiar “mushroom” shape and the high sweep angle values measured for late Pleistocene- Holocene fans (Fig. 3), can be interpreted as due to low subsidence and sea-level rise, combined with high sedi- ment input, which produce a retrograding stacking pat- tern, with a mountain embayment associated with an expansion of the fan (Viseras et al., 2003). Furthermore, the lack of fault evidence within the alluvial fan successions could be related just to the low rates of subsidence. As far as facies analysis are concerned, factors that control alluvial fan facies assemblages have been identified. Moving northward, T. Maddalena and T. Trappeto alluvial fan deposits consist of slightly different facies associations (Fig. 5). T. Maddalena piedmont fan was built solely by sediment gravity flows (debris avalanche and debris flow processes), whereas T. Trappeto pied- mont fan deposits consist of alternating sediment gravity flows (debris flow processes) and fluid gravity flows (sheetflooding). In both cases, secondary processes, i.e. overland flows, caused locally winnowing of the top surfaces. Some features, such as climate, vegetation types, tectonic setting etc. are thought to have been approximately the same during fan construction. Even though the T. Maddalena catchment area is larger than the T. Trappeto one (12.02 km2 vs. 6.26 km2), this featu- re, as other fan and catchment morphometric data, are not prerequisites to promote different facies assembla- ges (e.g. Blair, 1999). According to Blair (1999) and Blair & McPherson (1994), lithology of the bedrock underlying fan catchments is thought to control the slight differences in depositional processes and relative facies associations, i.e. weathering caused differences in sedi- ment particle-size, influencing permeability, which may promote sediment gravity flows vs. fluid gravity flows. Although the bulk of the bedrock underlying fan catch- ments at issue comprises quite similar lithologies, major exposures of schists and phyllites of the ophiolitic units in the T. Maddalena fan catchment (28% vs. 15%) may be considered as the main key factor in the differences among facies assemblages. Furthermore, the finer-grained facies, characteri- sing coastal fans in respect to piedmont ones (Robustelli et al., 2002), may be interpreted as the sedi- mentary response to different alluvial fan evolutionary stages, reflecting the progressive increase of drainage basins size, coupled with the decrease of drainage basins slope (e.g. Blair & McPherson, 1994). AACCKKNNOOWWLLEEDDGGMMEENNTTSS The authors are grateful to Mr. Francesco Colonnese for the preparation of thin sections. They also wish to thank Prof. L. Carobene and Prof. T. Pescatore for their comments and suggestions helpful for the improvement of the manuscript. This work is financially supported by MURST 60% (Prof. S. Crivelli). RREEFFEERREENNCCEESS Amodio-Morelli L., Bonardi G., Colonna V., Dietrich D., Giunta G., Ippolito F., Liguori V., Lorenzoni S., Paglionico A., Perrone V., Piccarretta G., Russo M., Scandone P., Zanettin-LorenzoniI E. & Zuppetta A. (1978) – L’arco calabro-peloritano nel- l’orogene appenninico-maghrebide. Mem. Soc. Geol. It., 1177, 1-60. Argnani A. & Trincardi F. (1988) – Paola slope basin: evi- dence of regional contraction on the eastern tyrrhe- nian margin. Mem. Soc. Geol. It., 4444, 93-105. Argnani A. & Trincardi F. (1993) – Growth of a slope ridge and its control on sedimentation: Paola slope basin (eastern Tyrrhenian margin). Spec. Pubbl. Int. Ass. Sediment., 2200, 467-480. 227Geomorphology, tectonics and sedimentology... Barone A., Fabbri A., Rossi S. & Sartori R. (1982) – Geological structure and evolution of the marine areas adjacent to the Calabrian Arc. Earth Evolution Sciences, 33, 207-221. Blair T.B. (1999) – Cause of dominance by sheetflood vs. debris-flow processes on two adjoining alluvial fans, Death Valley, California. Sedimentology, 4466,, 1015- 1028. Blair T.B. & McPherson J.G. (1994) – Alluvial fans and their natural distinction from rivers based on morphology, hydraulic processes, sedimentary processes and facies assemblages. J. Sedim. Research, A64, 33, 450-489. Bordoni P. & Valensise G. (1998) – Deformation of the 125ka marine terraces in Italy: tectonic implica- tions. In: Stewart I., Vita-Finzi C. (Eds), “Coastal Tectonics”, Geol. Soc. London, Spec. Pubbl. 114466, 71-110. Boullin J.P. (1984) – Nouvelle interpretation de la liason Apennine-Maghrébides en Calabre: consequen- ces sur la paléogéographie téthysienne entre Gibraltar et les Alpes. Rev. Geol. Dyn. Geogr. Phys., 2255, 321-338. Brancaccio L., Cinque A., Russo F., Belluomini G., Branca M., Delitala L. (1990) – Segnalazione e datazione di depositi tirreniani sulla costa campa- na. Boll. Soc. Geol. It., 110099, 259-265. Canu M. & Trincardi F. (1989) – Controllo eustatico e tettonico sui sistemi deposizionali nel Bacino di Paola (Plio-Quaternario), margine tirrenico orienta- le. Giornale di Geologia, 5511, 41-61. Carobene L. (1987) – Antiche linee di riva ed aspetti di geologia del quaternario. Guida alle escursioni nella Calabria settentrionale tra Marina di Maratea e Cetraro. 25-30 Maggio, 66pp.. Carobene L., Dai Pra G. & Gewelt M. (1986) – Niveaux marins du Pleistocene moyen-superieur de la cote tyrrhenienne de la Calabrie (Italie meridionale). Datations 230Th/234U et tectonique recente. Z. Geomorph. N. F., Suppl. Bd. 6622, 141-158. Carobene, L. & Dai Pra, G. (1990) – Genesis, chrono- logy and tectonics of the quaternary marine terra- ces of the Tyrrhenian coast of northern Calabria (Italy).Their correlation with climatic variations. Il Quaternario, 33, 75-94. Carobene L. & Ferrini G. (1993) – Morphological, sedi- mentological and tectonic features of Diamante- Mt. Carpinoso marine terrace flight (tyrrhenian coast of the northern Calabria, Italy). Earth Surf. Proc. Landforms, 1188,, 225-230. Chiocci F.L. (1995) - Very High-Resolution seismics as a Tool for Sequence Stratygraphy Applied to Outcrop Scale- Examples from eastern Tyrrhenian Margin Olocene /Pleistocene Deposits. AAPG bul- letin, vol. 7788, No 3 (March 1994), 378-395. Chiocci F.L., D’Angelo S., Orlando L. & Pantaleone E A. (1989) – Evolution of the Holocene shelf sedimenta- tion defined by high-resolution seismic stratigraphy and sequence analysis (Calabro-tyrrhenian conti- nental shelf). Mem. Soc. Geol. It., 4488, 359-380. Chiocci F.L. & Orlando L. (1995) – Effects of high fre- quency Pleistocene sea level changes on a highly deforming continental margin: Calabrian Shelf (Southern Tyrrhenian Sea, Italy) Bollettino di Geofisica Teorica ed Applicata, 3377, 39-58. Cinque A., De Pippo T., Romano P., 1995 - Coastal slope terracing and relative sea-level changes: Deductions based on computer simulations. Earth Surf. Process. Landforms, 2200,, 87-103. Colonna V., & Compagnoni R. (1982) - Guida all’escur- sione sulle Unità cristalline della Catena Costiera (Calabria). Rend. Soc. Geol. It. Min. e Petrol., 3388 (3), 1141-1152. Dewey J.F., Helmann M.L., Turco E., Hutton D.H.W. & Knott S.D. (1989) - Kinematics of the Western Mediterranean. In Alpine Tectonics, Coward, M.P., D. Dietrich and R.G. Park. (ed.s), Geol. Soc. Spec. Publ., 4455, 265-283. Di Nocera S., Oortolani F., Russo M., & Torre M. (1974) - Successioni sedimentarie messiniane e limite Miocene-Pliocene nella Calabria Settentrionale. Boll. Soc. Geol. It., 9933, 575-607. Dietrich D. (1976) - La Geologia della catena Costiera Calabra tra Cetraro e Guardia Piemontese. Mem. Soc. Geol. It., 1177, 61-121. Fabbri A., Gallignani P. & Zitellini N. (1981) – Geologic evolution of the peri-tyrrhenian sedimentary basins. In: Wezel F.C. (ed), “Sedimentary Basins in Mediterranean Margins”, Tecnoprint, Bologna, 101-126. Finetti I. & Del Ben A. (1986) - Geophisical study of the Tyrrhenian opening. Boll. Gef. Teor. Appl, 2288, 75- 155. Gallignani P. (1982) - Recent sedimentation processes of the Calabria continental shelf and slope (Tyrrhenian Sea, Italy). Oceanologica Acta, 55, 493-500. Harvey A.M., Silva P.G., Mather A.E., Goy J.L, Stokes M. & Zazo C. (1999) – The impact of Quaternary sea-level and climatic change on coastal alluvial fans in the Cabo de Gata ranges, southeast Spain. Geomorphology, 2288, 1-22. Iannace A., Romano P., Santangelo N., Santo A. & Tuccimei P. (2001) - The OIS 5c along Licosa cape promontory (Campania region, Southern Italy): morphostratigraphy and U/Th dating. Zeit. Geomorph., 4455(3), 307-319. Kastens K.A. & Mascle J. (1990) – Proc. Ocean Drilling Program, Scientific Results 107, Ocean Drilling Program, College Station, TX. Knott S.D. (1987) - The Liguride Complex of Souther Italy. A Cretaceous to Paleogene accretionary wedge. Tectonophysics, 114422, 217-226. Lowe D.R. (1982) – Sediment gravity flows II: Depositional models with special reference to the deposits of high-density turbidity currents. J. Sediment. Petrol., 5522, 279-297. Major J.J. & Pierson T.C. (1992) - Debris flow rheology: experimental analysis of fine-grained slurries. Water Resources Research, 2200, 3, 841-857. Mattei M., Cipollari P., Cosentino D., Argentieri A., Rossetti F., Speranza F., & Di Bella L. (2002) - The Miocene tectono-sedimentary evolution of the Southern Tyrrhenian Sea: stratigraphy, structural and paleomagnetic data from the onshore Amantea basin (Calabrian Arc, Italy). Basin Research, 1144, 147-168. Messina A, Barbieri M., Compagnoni R., De Vivo B., Perrone V., Russo S., & Scott B. (1981) - Geological and petrochemical study of the Sila Massif Plutonic rocks (Northern Calabria, Italy). Boll. Soc. Geol. It., 111100,165-206. 228 F. Muto et al. Muto F. & Perri E (2002) – Evoluzione tettono-sedimen- taria del Bacino di Amantea, Calabria occidentale. Boll. Soc. Geol. It., 112211, 391-409.. Nemec W. & Postma G. (1993) – Quaternary alluvial fans in southwestern Crete: sedimentation proces- ses and geomorphic evolution. In Marzo M., Puigdefabregas C. (Eds) Alluvial sedimentation. Int. Assoc. Sedimentol. Spec. Publ., 1177, 235-276. Nemec W. & Steel R.J. (1984) – Alluvial and coastal conglomerates: their significance features and some comments on gravelly mass-flow deposits. In: Koster E. H., Steel R. J. (ed.s). Sedimentology of gravels and conglomerates. Can. Soc. Petrol. Geol. Mem., 1100, 1-31. Ogniben L. (1973) - Schema geologico della Calabria in base ai dati odierni. Geol. Romana, 1122, 243-585. Patacca E., Sartori R. & Sscandone P. (1990) - Tyrrhenian basin and Appenninic arcs: kinematic relations since late Tortonian times. Mem. Soc. Geol. It., 4455, 425-451. Patacca E. & Scandone P. (1989) - Post tortonian mountain building in the Appennines. The role of passive sinking of a relic lithospheric slab. In: Boriani A., Bonafede M., Piccardo G.B. & Vai G.B. (eds), “The lithosphere in Italy. Advances in Earth Science Research” Atti Conv. Accad. Lincei, 8800, 157-176. Pierson T.C. (1980) – Erosion and deposition by debris flows at Mt. Thomas, North Canterbury, New Zealand. Earth Surf. Processes, 55, 227-247. Pierson T.C & Scott K.M. (1985) – Downstream dilution of a lahar: transition from debris flow to hypercon- centrated streamflow. Water Resour. Res., 2211, 1511-1524. Rehault J.P., Moussat E. & Fabbri A. (1987) – Structural evolution of the Tyrrhenian back-arc basin. Marine Geology, 112222, 5-21. Riccio A., Riggio F., Romano P. (2001) - Sea level fluc- tuations during Oxygen Isotope Stage 5: new data from fossil shorelines in the Surrento Peninsula (Southern Italy). Zeit. Geomorph., 4455(1), 121-137. Ridgway K.D. & DeCelles P.G. (1993) – Stream-domi- nated alluvial fan and lacustrine depositional systems in Cenozoic strike-slip basins, Denali fault system, Yukon Territoty, Canada. Sedimentology, 4400, 645-666. RobustelliI G., Muto F., Scarciglia F., Spina V. (2002) - Late Quaternary fan development and sea level change along the Tyrrhenian Sea coast of Calabria (Southern Italy). Studi Geologici Camerti, Nuova Serie, 22, 135-145. Scarciglia F., Terribile F., Colombo C. (2003) - Micromorphological evidence of paleoenvironmen- tal changes in Northern Cilento (South Italy) during the Late Quaternary. Catena, 5544 (3), 515-536. Shultz A.W. (1984) – Subaerial debris-flow deposition in the upper Paleozoic Cutler formation, western Colorado. J. Sediment. Petrol., 5544, 759-772. Smith G.A. (1986) – Coarse-grained nonmarine volca- noclastic sediment: terminology and depositional processes. Geol. Soc. Am. Bull., 9977, 1-10. Smith G.A. & Lowe D.R. (1991) – Lahars: volcano- hydrologic events and deposition in the debris flow-hyperconcentrated flow continuum. In: Fisher R. V., Smith G. A. (ed.s) Sedimentation in volcanic settings. SEPM, Spec. Pubbl., 4455, 59-70. Sohn Y.K., Rhee C.W. & Kim B.C. (1999) – Debris flow and hyperconcentrated flood-flow deposits in an alluvial fan, northwestern part of the Cretaceous Yongdong Basin, central Korea. J. Geol., 110077, 111-132. Sorriso-Valvo M. (1988) – Landslide-related fans in Calabria. Catena Suppl.,, 1133, 109-121. Sorriso-Valvo M., Antronico L. & Le Pera E. (1998) – Controls on modern fan morphology in Calabria, Southern Italy. Geomorphology, 2244, 169-187. Sorriso-Valvo M. & Sylvester A.G. (1993) – The relation- ship between geology and landforms along a coa- stal mountain front, northern Calabria, Italy. Earth Surf. Proc. Landforms, 18, 257-273. Sylvester A.G., Zeck S.E.A.,& Sorriso-Valvo M. (1987) - Tectonogeomorphic response to neotectonics, Southern Italy. International Symposium on the Tectonic Evolution and Dynamics of the Crustal Lithosphere, II Beijing, China, 1-3. Todd S. P. (1989) – Stream-driven, high-density gravelly traction carpets: possible deposits in the Trabeg Conglomerates formation, SW Ireland and some theoretical considerations of their origin. Sedimentology, 3366, 513-530. Tortorici L. (1982a) - Analisi delle deformazioni fragili dei sedimenti postorogeni della calabria Settentrionale. Boll. Soc. Geol.It., 110000(3), 291-380. Tortorici L. (1982b) - Lineamenti geologico strutturali dell’Arco Calabro-Peloritano. Rend. Soc.It. Mineral.e Petrol., 3388(3), 927-940. Tortorici G., Bianca M., Monaco C., Tortorici L., Tansi C. De Guidi G. & Catalano S. (2002) – Quaternary normal faulting and marine terracing in the area of Capo Vaticano and S. Eufemia plain (Southern Calabria). Studi Geol. Camerti, 11, 155-171. Tortorici L., Momano C., Tansi C. & Cocina O. (1995) – Recent and active tectonics in the Calabrian Arc (southern Italy). Tectonophysics, 224433,, 37-55. Turco E., Maresca R. & Cappadona P. (1990) – La tet- tonica Plio-pleistocenica del confine calabro-luca- no: modello cinematica. Mem. Soc. Geol. It., 4455, 519-529. Verstappen H.T. (1977) – A geomorphological survey of the NW Cosenza province, Calabria, Italy. ITC Journal, 44, 578-594. Viseras C., Calvache M.L., Soria J.M. & Fernandez J. (2003) - Differential features of alluvial fans con- trolled by tectonic or eustatic accommodation space. Geomorphology, 5500,181–202. Yarnold J.C. (1993) – Rock-avalanche characteristics in dry climates and the effect of flow into lakes: insi- ghts from the mid-Tertiary sedimentary breccias near Artillery peak, Arizona. Geol. Soc. Am. Bull., 110055,, 345-360. Yarnold J.C. & Lombard J.P.(1989) – Facies model for large block avalanche deposits formed id dry cli- mates. In Colburn I.P., Abbott P.L. and Minch J. (ed.s), Conglomerates in Basin Analysis. SEPM Pacific Section Symposium Book, 6622, 9-32. 229 Ms. ricevuto il 6 maggio 2003 Testo definitivo ricevuto il 19 settembre 2003 Ms. received: May 6, 2003 Final text received: September 19, 2003 Geomorphology, tectonics and sedimentology...