Massari, F. Et Al., (1999). Composite Sedimentary Record of Falling Stages of Pleistocene Glacio-eustatic Cycles in a Shelf Setting (Crotone Basin, South Italy)

ELSEVIER Sedimentary Geology 127 (1999) 85110

Composite sedimentary record of falling stages of Pleistoceneglacio-eustatic cycles in a shelf setting (Crotone basin, south Italy)

F. Massari a,, M. Sgavetti b, D. Rio a, A. DAlessandro c, G. Prosser da Dipartimento di Geologia, Paleontologia e Geofisica, Universita` di Padova, Via Giotto 1, 35137 Padova, Italy

b Dipartimento di Scienze della Terra, Universita` di Parma, Viale delle Scienze 78, 43100 Parma, Italyc Dipartimento di Geologia e Geofisica, Universita` di Bari, Campus universitario, Via E. Orabona 4, 70125 Bari, Italy

d Centro di Geodinamica, Universita` della Basilicata, Palazzo Auletta, Via Anzio, 85100 Potenza, Italy

Received 22 June 1998; accepted 18 March 1999

Abstract

A thick Pleistocene shelf and nearshore cyclical succession was deposited in the S. Mauro sub-basin of the Crotonebasin (southern Italy). The regressive units of the cycles are mostly represented by coastal siliciclastic and bioclasticprograding wedges showing a clinoform geometry. These are separated by blanket-like deposits of high lateral persistencerecording major transgressive episodes. The aim of this paper is (1) to describe facies patterns and depositional settingof two prograding wedges, particularly focussing on their polycyclic internal architecture, (2) to analyze these unitswithin a sequence-stratigraphic framework, and (3) to speculate on the possible origin of the small-scale cyclicity.The two wedges analyzed in this paper consist of a number of shingles. Individual shingles consist of two physicallyconnected units: (1) a relatively thin package of sigmoid clinoforms, grading into (2) a volumetrically dominant packageof oblique-tangential clinoforms with toplap terminations. The shingles are bounded by seaward-dipping surfaces withsigmoid clinoform geometry, which are ravinement surfaces updip, passing into conformable flooding surfaces downdip.The wedges are thus organized into high-frequency, small-scale sequences, each comprising transgressive, highstand andfalling-stage systems tracts. As a whole, individual prograding wedges are interpreted as forced-regressive units, as theshoreline was subject to an overall shift basinwards and downwards along a low-angle trajectory, in spite of the repeatedminor relative sea-level rises. Tectonic subsidence, and particularly the syndepositional growth of gentle synclines, arethought to have been the key factors allowing the preservation of these forced-regressive units. Progradation of thewedges took place in a high-energy wave climate characterized by high frequency of storms and very efficient alongshoreredistribution of sediments. Recurrent, storm-driven, offshore currents led to intense reworking of sediments on thetopset platform and gravity spreading on the foreset slope of the prograding wedges. Well-oxygenated conditions overthe shelf due to intensified storm activity during glacial periods may have enhanced the rate of production of skeletal,foramol-type carbonates. It can reasonably be assumed that progradation took place from a line source and that the sandbodies are to be regarded as coastal prograding bodies. In spite of active syndepositional tectonics, the cycles can becorrelated to Pleistocene high-amplitude sea-level oscillations. The older of the two wedges can be correlated, throughbio-magnetostratigraphy, to the major climatic transition which occurred from the marine oxygen-isotope stage 25 to 2422(Rio et al., 1996). The younger probably developed during the sea-level fall that ended with substage 18.2, as suggestedby sequence- and bio-stratigraphic data. The prograding wedges are thus interpreted to record long-lived sea-level fallsof fourth-order cycles. Due to the particular depositional setting, we are inclined to exclude authigenic mechanisms in

Corresponding author. E-mail: [email protected]

0037-0738/99/$ see front matter 1999 Elsevier Science B.V. All rights reserved.PII: S 0 0 3 7 - 0 7 3 8 ( 9 9 ) 0 0 0 2 5 - 1

86 F. Massari et al. / Sedimentary Geology 127 (1999) 85110

the origin of small-scale cyclicity. Although the concomitance and interaction of different controlling factors may betaken into account, it is tempting to ascribe this cyclicity to minor eustatic changes punctuating long-lived, erratic fallingstages, possibly accompanied by climate-driven fluctuations of sediment supply. Shelf-perched and shelf-edge progradingunits consisting of foramol-type carbonates are apparently a common falling-stage to lowstand depositional feature in theMediterranean area during the Late Pliocene and Pleistocene. 1999 Elsevier Science B.V. All rights reserved.

Keywords: Pleistocene; glacio-eustasy; shallow-water cycles; forced regression; composite prograding wedges; shingles;high-energy wave climate; oxygen-isotope record; erratic sea-level fall; minor eustatic changes

1. Introduction

Late-Early Pleistocene to Late Pleistocene sea-level cycles, as recorded by the 18O composi-tion of the calcite in foraminifera (Shackleton,1987), are characterized by fluctuating, long-livedglacial buildups, terminated typically by large andabrupt shifts from glacial to interglacial conditions(Broecker and van Donk, 1970; Broecker, 1984;Raymo, 1997). These sea-level fluctuations maycombine with basin subsidence and sediment supplyto produce sedimentary cycles with facies distribu-tion and sequence architecture that differ from thosepredicted by current sequence-stratigraphic models(Piper and Perissoratis, 1990, 1991; Aksu et al.,1992; Tesson et al., 1993; Naish and Kamp, 1997).Specifically, well-developed Pleistocene progradingunits recording sea-level falls, sometimes punctuatedby short-term landward shifts in coastal onlap, havebeen illustrated in various settings (Aksu et al., 1992;Posamentier et al., 1992; Tesson et al., 1993; Trin-cardi et al., 1996; Trincardi and Correggiari, 1999).

In a recent paper, using bio-magnetostratigraphicconstraints, we documented the correlation with thestandard oxygen-isotope scale of Lower to middlePleistocene mixed siliciclasticcarbonate cycles, de-veloping in the small, tectonically active S. Maurosub-basin of the Crotone basin, southern Italy (Rioet al., 1996). The development and preservation ofthese deposits resulted from differential tectonic sub-sidence and high rates of sediment supply. In this pa-per we illustrate in detail (1) facies patterns and depo-sitional setting of the coastal prograding units whichmake up the most part of these cycles, particularly fo-cussing on the composite internal stratal architectureof two of them, (2) the analysis of these units withina sequence-stratigraphic conceptual framework, and(3) the possible origin of the small-scale cyclicity.

The nearshore to shelf setting of the investigatedsuccession is similar to that of the classical Pleis-tocene cycles of the Wanganui basin of New Zealand(Kamp and Turner, 1990; Carter et al., 1991; Abbott,1997; Abbott and Carter, 1997; Naish and Kamp,1997), although significant differences in the cyclesinternal architecture can be highlighted.

2. S. Mauro sub-basin

The Calabrian segment of the Apennines, cor-responding to the rear of the Calabrian accre-tionary wedge (Fig. 1), recently evolved from EarlyPleistocene compression, through middle Pleis-tocene strike-slip faulting, to Late Pleistocene ex-tension and isostatic adjustments (Scheepers, 1994).Within this setting, the evolution of the Crotonebasin was controlled by oblique sinistral move-ments along two confining NW-trending crustalshear zones (RossanoSan Nicola and PetiliaSostriZones, Fig. 1) (Van Dijk, 1991). Small sub-basinsoriginated within the Crotone basin during the EarlyPleistocene, one of which is located in the S.Mauro Marchesato area. This sub-basin, boundedby M. Fuscaldo and Scandale synsedimentary faults(Fig. 2), evolved in a dextral transtensile bend of anoverall NNE-oriented extensional stress field, whichcaused enhanced differential subsidence and dis-placements of active depositional sites, as recordedby angular stratal relationships and unconformities.

Syndepositional NE- to NNE-trending folds withvery low amplitude are sub-parallel to boundary faultsand are more accentuated close to them, suggestinga genetic relationship with fault movements. Theirgeometries closely resemble those which developedin the hanging-wall of listric extensional faults withstaircase trajectory (Gibbs, 1984; Ellis and McClay,

F. Massari et al. / Sedimentary Geology 127 (1999) 85110 87

Fig. 1. Geological setting of study area (shown by rectangle), with indications of main geological units of southern Italy (adapted fromVan Dijk, 1994). Evolution of the Crotone basin was controlled by two NW-trending crustal shear zones, RossanoSan Nicola andPetiliaSostri zones.

1988; Xiao and Suppe, 1992). They may result fromhanging-wall deformation related to listric fault ge-ometries in a dextral transtensile tectonic setting.Change in along-strike displacement led to variabil-ity in stratigraphic style, some segments being char-acterized by growth folds creating sediment wedgesthinning towards the fault, and other segments typ-ified by rollover geometries (e.g. section AA0 inFig. 2), with thickening and diverging stratigraphytowards the fault zone (cf. Gawthorpe et al., 1997).This tectonic setting is also supported by presence ofminor normal faults crossing the succession, relatedto nearly NWSE extension.

The infill of the S. Mauro Marchesato sub-basin represents a relatively expanded sedimentaryrecord of the upper-Lower Pleistocene and middlePleistocene (we follow Berggren et al., 1995 inplacing the Earlymiddle Pleistocene boundary atthe MatuyamaBrunhes reversal). Five stratigraphicunits are recognized (Fig. 3), informally namedCutro 1 and Cutro 2 (Cutro group), S. Mauro 1,S. Mauro 2 and S. Mauro 3 (S. Mauro group) (Rioet al., 1996). Relatively high rates of subsidence andsediment supply, combined with deposition in shal-low-water environments sensitive to even minor rela-tive sea-level changes, resulted in a stack of high-fre-


quency unconformity-bounded cycles, particularlyin Cutro 2 and the S. Mauro group (Rio et al.,1996). The arkosic composition of siliciclastic sandsof the S. Mauro group suggests provenance fromthe nearby uplifting granitic Sila massif, presumablythrough short-headed, high-gradient streams.

Although the large-scale stratigraphic organiza-tion of the succession is strongly influenced bytectonics, chronological constraints from calcareousnannofossil biostratigraphy and magnetostratigraphyindicate that the transgressive episodes within Cutro2, S. Mauro 1 and S. Mauro 2 are synchronous withmarine oxygen-isotope stages (MIS) 33 to 19; thematch between corresponding physical cycles andthe global oxygen-isotope curve provides convinc-ing evidence that the cycles are the result of globaleustasy (Rio et al., 1996).

The S. Mauro group includes a wide range of sedi-ments ranging from outer-shelf muds to braided-riverconglomerates. S. Mauro 1 consists of a complex pro-grading unit, followed by a mud-dominated, domi-nantly aggrading interval (S. Mauro 2). Two majortransgressions are recognized in this interval. In theyounger of them the MatuyamaBrunhes boundary isrecognized, allowing a correlation with MIS 19 (Rioet al., 1996). MIS 19 muds include an ash layer trace-able throughout the study area. Above this stage, cor-relation of the sedimentary cycles with marine isotopestages could not be carried out because of the lackof rigorous chronological constraints. A progressiveslowing-down of the subsidence rate during the latestage of basin filling led to an upward increase in theamounts of lagoonal and fluvial deposits (Fig. 3), andincreasing incompleteness of the cycles. As a whole,therefore, the S. Mauro group shows an overall back-stepping to progradational vertical stacking pattern ofthe cycles probably reflecting the long-term trend ofregional subsidence.

Fig. 2. Simplified geological map of study area. To the west, S. Mauro sub-basin is bounded by the N-directed dextral oblique-slip M.Fuscaldo fault, which forms a releasing bend in the S. Mauro area; to the east, it is bounded by the dextral oblique-slip Scandale fault,characterized by major extensional component. Both faults were active during sedimentation, and movements along them took place in aNNE-oriented extensional stress field. Syndepositional NE- to NNE-trending folds with very low amplitude are sub-parallel to boundaryfaults and are more accentuated close to them, suggesting genetic relationship with fault movements. The Cutro group is dated to EarlyPleistocene and S. Mauro group to late-Early Pleistocene and middle Pleistocene. AA0, BB0 and CC0: geological sections (tracesin map) illustrating effects of syndepositional tectonics (note vertical exaggeration). Section BB 0 shows that the depocentre activeduring deposition of S. Mauro 1 and S. Mauro 2 shifted westwards during deposition of S. Mauro 3. For the sake of clarity internalunconformities of composite wedges are omitted in section CC0.

The infill of the S. Mauro sub-basin was followedby late-middle Pleistocene to Recent uplift, whichled to the formation of a number of marine terraces.The oldest one of these (not mapped in Fig. 2) isascribed to MIS 7 (Gliozzi, 1987; Cosentino et al.,1989) or MIS 9 (Palmentola et al., 1990). If thesecond case were true, the average uplift rate in theLate Pleistocene would have been ca. 0.4 m=ky.

3. Prograding composite wedges

In the S. Mauro group the bulk of the sedimentvolume is represented by prograding units, whichare mainly sand-dominated wedges with clinoformgeometry (Figs. 3 and 4). They are bounded at thetop by discontinuity surfaces overlain by aggrad-ing, blanket-like deposits of high lateral persistence,showing evidence of base-level rise. The latter rangefrom generally thin, fossiliferous, coarse shorefacedeposits, erosively underlain in the upper cycles byfluvial incised-valley fills grading upwards into la-goonal muds, to conformable marine offshore mud-stones (especially in most subsiding areas at the topof S. Mauro 1, e.g. Valle di Manche section).

Two wedges are particularly prominent within theS. Mauro group (Fig. 4), each prograding for almost5 km down depositional dip. The lower one (A inFigs. 3 and 4) comprises S. Mauro 1 unit. The upperone (B in Figs. 3 and 4) is located in the lower partof S. Mauro 3.

3.1. Internal organization

Wedges A and B (Fig. 4) have a composite inter-nal architecture. Each wedge consists of a number ofphysically connected shingles, details of which areshown in Figs. 59 and described in Table 1. Due


Fig. 3. Generalized stratigraphic section of study area, with indication of bio- and magnetostratigraphy, and correlation with standardoxygen isotopic scale. A and B represent composite wedges studied here.

F.M

assari

etal./Sedim

entaryG

eology127(1999)85

11091

Fig. 4. Dip-oriented cross-section along the eastern side of the basin fill, from Scandale fault to T.S. Margherita, showing stacked cycles of S. Mauro 1, S. Mauro 2 andlower part of S. Mauro 3. Note general geometry of wedges A and B and their internal subdivision into a number of shingled units. Flanks of broad gravel-filled incisedvalley at the top are not apparent, as section is sub-parallel to palaeoflow direction. Vertical scale is enlarged.


Fig. 5. Photo and sketch of segment of lower composite wedge in S. Mauro S section (see Fig. 2 for location) showing unconformablecontact (arrow) of two shingled units, draped by coarse shoreface deposits. Section is oblique to depositional dip of clinoforms.

to erosional termination of the outcrops of S. Maurogroup on the basinward side, only a conservativeestimate of the number of shingles can be made.Six shingles are recognized within wedge A and fivewithin wedge B.

3.2. Depositional setting

A number of features suggest that the progradingunits were deposited as strike-fed coastal lithosomesdeveloped in a high-energy wave climate: (1) thelargely bioclastic composition of some shingles, in-cluding well rounded shell remains, with evidence ofintrabasinal source located on topset platforms; (2)

textural features of the sands, which are commonlyvery well sorted, especially in the topset of the units,pointing to efficient winnowing by wave action; (3)sedimentary structures observed in the topset beds,all indicative of a high-energy wave-dominated set-ting (Fig. 7). Strike-oriented trough cross-beds sug-gest a genetic link with very efficient longshoredrift. Wave megaripples, offshore-directed troughcross-beds and swaley cross-beds suggest the ac-tivity of high-energy waves and storm-driven flows.All these features indicate active wave-reworkingand efficient along-shore redistribution of sediments.

The arkosic composition of siliciclastic sands sug-gests provenance from the nearby rising granitic

F.M

assari

etal./Sedim

entaryG

eology127(1999)85

11093

Fig. 6. (a) Sketch from photomosaic showing internal organization of upper composite wedge, as seen in Valle di Manche section, oriented slightly oblique to depositionaldip of clinoforms (see Fig. 2, section CC0, for location). Note enlarged vertical scale. This wedge is internally subdivided into shingled units by prominent, seaward-dippingsurfaces with sigmoid clinoform geometry, updip portions of which are erosional unconformities mantled by shoreface deposits. Wedge is capped by a regional unconformity,above which shoreface sands of another cycle are variably eroded by a broad incised valley infilled with braided-river deposits. These in turn are capped by a transgressivesheet. (b) Wedge segment showing detail of geometry of unconformity surface (arrows) at junction of two shingled units. (c) Detail of unconformity (ravinement surface)between two shingled units. Contact is marked by erosional gutters and is overlain by three closely spaced coarse fossiliferous bands, interlayered with fine sand. Hoe 67 cmlong for scale.


Fig. 7. Vertical facies sequence of upper prograding wedge (reconstructed from a number of partial sections measured in the southernpart of the study area). Note that palaeocurrent pattern in topset beds is comparably much more variable than in foreset beds, where dipof trough cross-bedded intrasets approximates clinoform dip.

F.M

assari

etal./Sedim

entaryG

eology127(1999)85

11095

Fig. 8. Details of siliciclastic units of upper composite wedge. (a) Trough cross-bedding and mud-draped wave megaripples in upper part of topset beds. Hoe 67 cm longfor scale. (b) Swaley cross-stratification in topsets. (c) Rhythmic pattern of foreset beds due to recurrent physical emplacement of event beds and intervening bioturbation,mainly echinoid meniscate traces. (d) Echinoid meniscate traces on a stratification surface of foreset beds.

96F.M

assari

etal./Sedim

entaryG

eology127(1999)85

110Table 1Facies scheme of composite wedges

General features of thecomposite wedges

Stratal architecture Stratal architecture of individual shingles (Fig. 7) Faunal=floral elementsTopset beds Foreset beds Toeset and bottomset beds

Light-brown to yellowish,prograding,upward-shallowing wedgesup to 45 m thick, with basalcontact changing fromsharp-erosional (locallymarked by intraclast and=orshell lags) to gradationalbasinwards. Grain size fromsilt=fine sand to granule-and rarely pebble=cobblegravel; sand predominates.Sorting good to moderate,best in fine sand. Coarsestdeposits (up to pebbles andcobbles) typically occur inmost basinward locatedunits. Composition frompurely siliciclastic (arkosicsands, with clasts of quartzand granite in the coarserfractions) to mixed, withlocally high bioclasticcontent especially in wedgeA (Fig. 9a,b).

Wedges A and B displaycomposite internalarchitecture consisting of anumber of shingles. Withinindividual shingles an early,thin package of sigmoidclinoforms recording ashort-way progradationaccompanied by slightlandward encroaching ofcoastal onlap, is physicallyconnected with avolumetrically dominantpackage ofoblique-tangentialclinoforms with toplapterminations. The shinglesare bounded byseaward-dipping sigmoidsurfaces (Fig. 6) which areunconformable updip,becoming conformable atthe asymptotic toe of theshingles. These surfaces areblanketed updip byfossiliferous sheets ofgravelly sand 13 m thick,grading downdip intooffshore marine muds.

Sandy to gravelly topsetbeds are preserved only atthe top of the packages ofsigmoid clinoforms. Atopmost division, commonlyremoved by subsequenterosion, shows strike- anddowndip-oriented troughcross-bedding, planarlamination and wavemegaripples (Figs. 7 and8a). Local storm-wave shellpavements. This divisiongrades downwards into acommonly preserved swaleycross-bedded (Figs. 7 and8b) and planar-laminateddivision with abundantechinoid meniscate traces.

Regularly stratifieddecimetre-thick layers(Fig. 7) ranging in grain sizefrom fine sand to granulegravel, locally with thinmuddy interbeds increasingin thickness and abundancedowndip. Dip angles fromless than 10 to 16 (Fig. 9d)according to grain size andgradient of the substrate.Beds mostlyplanar-laminated (Figs. 7and 8c). Normal gradingmay occur in both fine- andcoarse-grained layers,inverse grading occasionallyin the latter. Typicalrhythmic pattern due torecurrent physicalemplacement of event bedsand intervening bioturbation(Fig. 8c). Shells mostlyconvex-up, locallyimbricated with low to highimbrication angles. Localconvolute patterns. Rare setsof scour-based backset beds(Fig. 7) recording upslopemigration of hydraulicjumps (Massari, 1996).Abundant echinoidmeniscate traces (Fig. 8d)locally associated with thintubes of polychaetes andescape burrows.

Foreset beds mergeasymptotically downdip intoheavily to completelybioturbated toesets andbottomsets (Fig. 7),interbedded with downdipincreasing amounts of bluishmud. Some layers arecrossed by sparseThalassinoides burrows anddensely penetrated in theupper part by sub-horizontalto slightly oblique,unwalled, non-branchingburrows 0.5 cm in diam.Downdip increase in mudcontent suggests that theenergy of the system waslowest in the toeset andbottomset, allowing settlingof fines from suspension.

Arctica islandica isabundant in wedge A.Skeletal content of highlybioclastic units consists ofdisarticulated, whole orbroken and commonlyabraded molluscan shells,bryozoa, serpulids, echinoidfragments, branches ofcorallines and rhodoliths, ina matrix of comminutedbio-debris (foramol-typeskeletal concentrations)(Fig. 9b). Skeletalassemblages are ecologicallymixed, with the imprints ofvarious taphonomicprocesses and evidence ofinitial residence above thefair-weather wave basebefore later transport andredeposition. Elementsexhumed from the substrateare mixed withshallow-water coevalelements. Details on thefaunal and floral elementscan be found inAppendix A.

F.M

assari

etal./Sedim

entaryG

eology127(1999)85

11097

Fig. 9. (a) Segment of highly bioclastic unit with clinoform geometry, about 15 m high (lower composite wedge). Planar erosional top surface (arrow) is mantled bysiliciclastic shoreface sands. (b) Detail of foreset beds: small rhodoliths and fragments of bivalves in a matrix of comminuted bioclastic debris. (c) Progressive angularunconformity on southern wall of Timpone S. Margherita (see Fig. 2, section BB0, for location). (d) Steep-inclined foreset beds (upper composite wedge).


Sila massif, presumably through short-headed, high-gradient streams. However, sedimentary structuresand stratal geometries indicate that coastal processesplayed a dominant role in longshore redistributionof sediments and straightening of the coast, so thatlocalized and discrete deltaic protuberances of theshoreline were most probably absent. Progradationaladvance of the shoreline across the shelf led todecreasing shelf width and increasing exposure toopen-water waves, and coastal systems consequentlybecame more wave-influenced, with maximization ofstorm reworking (Einsele, 1993; Galloway and Hob-day, 1996). Frictional coupling between the windand the water surface during recurrent storms causedcoastal setup and water to be driven offshore, leadingto intense reworking of sediments on the topset plat-form and gravity spreading of sediment-laden flowson the foreset slope of the prograding units (cf. Saito,1991; Laptas, 1992; Tesson et al., 1993; Chiocci andOrlando, 1996; Hanken et al., 1996; Hernandez-Molina et al., 1998; Pomar and Tropeano, 1998;Chiocci and Romagnoli, 1999).

In the case of richly bioclastic units, there is clearevidence that foramol-type deposits were producedon a shallow-water platform located in topset posi-tion. Wave action reworked and comminuted skeletalmaterial temporarily resident above the fair-weatherwave base, while redeposition by sediment gravity-flows on to the foreset slope below fair-weather wavebase produced amalgamated, densely packed concen-trations. The above processes generated a characteris-tic type of multiple-event skeletal concentrations withan important lag component (sensu Kidwell, 1991).

Undoubtedly the studied prograding bodies arequite peculiar units, as they cannot be comparedto the usual coarsening-upwards units resulting fromthe progradation of a beach face, nor may they be de-fined as a sort of deltaic unit. They are significantlydifferent from typical shoreface prograding units,which commonly show much lesser dip angles ofclinoforms (on average 0.3 according to Walker andPlint, 1992). Main differences include the length andsteep inclination of clinoforms, importance of sedi-ment gravity flows on the foreset slopes, and depthattained by toeset beds, which extend into the off-shore zone, well below the fair-weather wave base.We will use the term coastal prograding wedges asthey were most probably connected to the shoreline

and shaped by coastal processes. Comparable mid-shelf and shelf-margin prograding deposits emplacedduring falling and lowstand Pleistocene stages on theTyrrhenian Sea margin were interpreted by Trincardiand Field (1991) to have formed by coastal progra-dation as beachshoreface complexes. Units withcomparable internal architecture were referred to asinfralittoral prograding wedges=prisms by Pomarand Tropeano (1998) and Hernandez-Molina et al.(1998).

3.3. Surfaces bounding the shingled unitsThe surfaces with sigmoid clinoform geometry

bounding the shingled units (Figs. 5 and 6) are un-conformably blanketed updip by fossiliferous sheetsof gravelly sand 13 m thick. These fine progressivelydowndip into conformable offshore muds. The coarsedeposits generally consist of sheet-like granule- topebble-conglomerates with a sandy matrix, contain-ing sparse to densely packed skeletal remains (pec-tinids, echinoids) and locally bored pebbles and pe-dorelics. From the pebble-strewn erosional surfaces,subvertical burrows (probable Cylindrichnus), some-times surrounded by thin polychaete burrows, locallypenetrate deeply downwards into the sandy substrate.

The unconformable surfaces are locally markedby erosional gutters up to 20 cm deep (Fig. 6c),or shallow scours (Fig. 5) with high width=depthratio, up to 2.1 m deep. The gutters sometimes dis-play vertical walls and are infilled with the coarsestavailable elements, commonly with normal grading.The infills of the scours range in grain size fromgranule sand with sparse pebbles to medium sand,and in composition from siliciclastic to richly bio-clastic. They consist of a number of scour-based,bipartite beds, 2040 cm thick. The lower divisionsof the beds are massive or normally graded, poorlysorted, with chaotic fabric, and contain abundantmud clasts, well-rounded pebbles (mostly quartzand granite), sparse pedorelics (small reworked cal-crete nodules), and sometimes variably fragmented,abraded and bio-eroded shells (including pectinidsand Arctica islandica, mostly with concave-upvalves) and rhodoliths. The upper divisions are pla-nar- to low-angle-laminated, better sorted, sandy togranular, and locally mud-draped. They may showgood imbrication of small bioclasts with a dominant


mode indicating basinward flow, and a subordinateopposite mode. Some layers show echinoid menis-cate traces or mud-draped wave ripples at the top.The above bipartite pattern suggests deposition byhighly turbulent and highly concentrated flows andfinal reworking by traction=oscillatory processes.

The scour infills commonly grade upwards intoextensive, 12 m thick blankets of planar- to low-angle-laminated, well-sorted sand.

3.3.1. InterpretationThe deposits veneering the unconformity surfaces

are coarse lags resulting from reworking of formerdeposits during phases of active shoreface retreat.The unconformities are therefore ravinement sur-faces. Their correlative downdip conformities, man-tled by silty muds, may be regarded as marine flood-ing surfaces in distal position. The relatively steepgradients of landward-migrating shoreface envelopeswere controlled by the dip angles of underlying beds,and probably also by high rates of relative sea-levelrise. The shallow, broad erosional lows infilled withcoarse deposits suggest that the ravinement processrelated to shoreface retreat may have been accom-panied by localized scour. A variable erodibility ofthe substrate may have been controlled by differen-tial cementation achieved during a previous stage ofsubaerial exposure (cf. Trincardi and Field, 1991). Acertain degree of cementation is also suggested bythe evidence of limited effects of erosion during thestages of shoreface retreat along the surfaces bound-ing the shingled units, and subsequently along themajor unconformity surfaces bounding the compos-ite wedges. Actually the only clearly recognizableerosional effect, except for the above mentionedscours, is the common removal of the uppermost partof the topset of the shingled units.

4. Sequence stratigraphy of composite wedges

Geometry and stratal architecture of the studiedwedges and their relationships with the substrateindicate that progradation took place on to the shelfand that no shelf-margin units are present in thepreserved part of the infill of S. Mauro sub-basin.

Several authors have drawn attention to the im-portance of shelf and nearshore prograding deposits

forming during relative sea-level falls, and have dis-cussed the significance of these deposits within a se-quence-stratigraphic framework (Plint, 1988, 1991;Walker and Plint, 1992; Hunt and Tucker, 1992,1995; Helland-Hansen and Gjelberg, 1994; Naishand Kamp, 1997, among others).

In our study area, we recognized two differentscales of cyclicity.

(1) On the larger scale, the two composite wedgesare thought to record accretionary forced regres-sions (sensu Helland-Hansen and Gjelberg, 1994) offourth-order sequences. The interpretation in termsof forced-regressive wedges stems from the evidencethat the shoreline was subject to an overall shift bas-inwards and downwards along a low-angle trajectory,in spite of repeated minor relative sea-level rises, andthat coarsest deposits occur within the most distalparts of the composite wedges (T.S. Litano section).The major discontinuities bounding the wedges at thetop are interpreted as fourth-order sequence bound-aries. These are draped by aggrading blanket-likedeposits showing high lateral persistence and lack ofbackstepping patterns, which record major episodesof relative sea-level rise.

(2) On the scale of individual shingled units(Fig. 10), the sigmoid packages of clinoforms re-flect progradation concomitant with the creation ofaccommodation. Oblique, offlapping packages re-flect progradation in a setting of slowly decreasingaccommodation. The basinward and downward dis-placement of the shoreline during this stage is provedby the physical lowering of the toplap surface andthe fact that subsequent shoreface retreat producinga ravinement surface starts from a point located sig-nificantly downdip along the front of the progradingbody. Blanket deposits covering erosional unconfor-mities between shingled units reflect minor, high-frequency events of relative sea-level rise. The un-conformities are ravinement surfaces which removedany evidence of previous subaerial exposure. Theircorrelative downdip conformities, mantled by siltymuds, are marine flooding surfaces in distal position.

The attribution of a sequence-stratigraphic signif-icance to the shape of clinoforms (sigmoid versusoblique) is shared by Christie-Blick (1991) and Hel-land-Hansen (1993). The latter regards the clinoformshape as an indirect criterion for estimating the ratioof accommodation to supply.


Fig. 10. Scheme of development of shingles as component units of prograding composite wedges (terminology is that suggested byHelland-Hansen and Gjelberg, 1994).

Following the nongenetic, descriptive nomencla-ture of Helland-Hansen and Gjelberg (1994), theblanket deposits covering the shingle-bounding sig-moid unconformities should be ascribed to non-accre-tionary transgression, the packages of sigmoid cli-noforms to normal regression and the packages ofoblique-tangential clinoforms to accretionary forced-regression. Thus, the composite wedges are organizedinto higher-order, small-scale depositional sequences.If reference is simply made to the stratal architecture,without genetic implications, it may be stated thateach small-scale sequence consists of transgressive,highstand and falling-stage systems tracts (Fig. 11).

A similar partitioning into minor cycles has beenrecognized by Somoza et al. (1997) in an Upper Pleis-tocene major progradational wedge of the Gulf ofCadiz, Spain, using high-resolution seismic profiles.

The lack of an intervening zone of sediment by-pass between sigmoid and oblique packages of the

shingled units indicates a continuum between thetwo systems tracts (Fig. 10) (Ainsworth and Pat-tinson, 1994; Naish and Kamp, 1997). This stratalarrangement is different from the model of Plint(1988) (see also Posamentier et al., 1992), in whicha temporary increase in the rate of relative sea-levelfall leads to a basinward jump in the position of theshoreline and a separation of the falling-stage fromthe highstand unit.

In the study area, the successive shingles of com-posite wedges are physically adjacent to one anotherwithout a downstepping pattern, due to episodic risesof coastal onlap between the successive phases offorced regression. The subsidence rate is thought toplay a critical role in determining the presence ornot of a downstepping pattern. The architecture of S.Mauro composite wedges, and particularly the shin-gled pattern of offlapping deposits occurring aboveravinement surfaces, is similar to that described by


Fig. 11. Reconstructed and partly idealized pattern of stratal architecture of lower composite wedge. Landwards, it pinches out against agrowing structure related to the Scandale boundary fault. Progradation is punctuated by minor transgressive events. Clinoforms rapidlyevolve from sigmoid to oblique-tangential configuration within individual shingled units (TST D transgressive systems tract; HST Dhighstand systems tract; FRST D forced regressive systems tract; DWS D downward shift of facies tracts. All labels refer to higher-ordercycles within composite wedge) (approximate scale on left).

Dominguez et al. (1992) in the upper Cenozoic shal-low-water depositional systems of Brazil.

The term FRWST (forced-regressive wedge sys-tems tract) was originally attributed to forced-regres-sive wedges detached from the HST and occurringas a series of downstepped, disjoined, sharp-basedshoreline wedges (Hunt and Tucker, 1992; see alsoPosamentier et al., 1992). Although our architec-tural setting is different, we do not see good reasonsfor using another term (we only would simplifythe acronym into FRST). Naish and Kamp (1997)suggest regressive systems tract (RST) as a moreappropriate term for describing forced-regressive de-posits physically attached to the HST and marked bygradational lower contact. We agree with them thatthis stratal architecture may be a common feature ofPlioPleistocene sequences. However, we actuallyshare the opinion of Mellere and Steel (1995) thatthe nature of the lower contact and the attached ordetached relationship with respect to the HST are

not the sole key features for defining a forced-regres-sive wedge. Other criteria are regarded as critical,such as the evidence that the shoreline is drivenbasinwards along a downward-directed trajectory(Helland-Hansen and Gjelberg, 1994), the downwardshift of facies in successive clinoform segments, andthe progressive basinward coarsening of sedimentsresulting from the lowering of base level.

5. Can composite wedges be correlated with theoxygen-isotope record?

For the Pleistocene, the history of sea-level fluctu-ations is largely known, since an independent high-resolution proxy of sea-level change is available inthe form of the global oxygen-isotope record. Conse-quently, correlations may be established between thedifferent systems tracts and the successive phases ofthe sea-level cycle, provided that a firm chronostrati-


graphic and depositional framework can be deducedfrom available bio- and magnetostratigraphic con-straints combined with palaeo-environmental obser-vations (Naish and Kamp, 1997). Data of this qualityare available here, at least concerning the lower com-posite wedge. Bio- and magnetostratigraphic data(Rio et al., 1996; and summarized in Fig. 3) demon-strate that this body is bounded at the base and topby two transgressive horizons correlated with MIS25 and MIS 21, respectively. Thus wedge A may becorrelated with the shift from MIS 25 to MIS 22.Indeed, the period of development of the lower com-posite wedge includes interglacial MIS 23. However,the sedimentary expression of this stage cannot bedistinguished from other minor transgressions whichpunctuate the overall regressive pattern of the lowercomposite wedge. Moreover, this oscillation is only aminor interglacial stage on a longer-term fall. Abbottand Carter (1994) found that MIS 23 was too smallto produce a discrete cycle.

We may argue, therefore, that the major faciesbreak associated with the base of wedge A correlateswith the onset of the MIS 2422 interval, which isknown to correspond to a major transition of theEarths climatic system, marking the gradual onsetof the glacialinterglacial 100-ky cycles (Prell, 1982;Ruddiman et al., 1989). The physical expression ofthis transition is a major fall of sea level, possiblyenhanced by synsedimentary tectonics, reflected bya change from the muddy sedimentation of the Cutrogroup to the sand-dominated sedimentation of the S.Mauro group. The abundance of Arctica islandica isparticularly significant, as this species is considered atypical element of boreal cold-water faunas enteringthe Mediterranean during glacial intervals.

Correlation of the upper part of the S. Maurosuccession, including wedge B, with the oxygen-iso-tope record is comparably much less constrained.Palynological data (R. Bertoldi and L. Caprara, pers.commun., 1998), indicate that the record of MIS 19is bipartite, in accordance with the indications oflow-latitude stack of Bassinot et al. (1994). In addi-tion, the progradation of the overlying sand wedgedeveloped in concomitance with a marked shift to-wards arid vegetational conditions, most probablycorresponding to the cooling period from 19.1 to18.4, and terminates with a horizon showing evi-dence of a mitigation of these conditions together

with physical evidence of a transgression (recordedby a locally preserved fossiliferous lag in a silty,deeply burrowed matrix), which might correlate withsubstage 18.3 (Fig. 3).

Wedge B developed as a prograding unit abovethis transgressive horizon and is in turn overlain bythe deposits of another cycle that have been erodedto a variable extent, and locally completely removed,by a broad incised valley (Figs. 3, 4 and 6). Thelatter was infilled with braided river deposits, in turngrading upwards into lagoonal and marine deposits;these contain P. lacunosa (Fig. 3), hence are olderthan late MIS 12, as the extinction of this marker isknown to have occurred in the late MIS 12 (Thier-stein et al., 1977). Fluvial deposits represent the firstimportant record of continental sedimentation in thebasin. Although the deep erosion at their base wasprobably enhanced by tectonics, it is tempting to cor-relate this base-level fall with the marked sea-leveldrop indicated by substage 16.2. Furthermore, thelateral persistence and importance of the transgres-sive deposits overlying the fluvial complex matchesquite well with the pronounced and abrupt termina-tion VII at about 0.6 Ma (Fig. 3). It may therefore beconcluded that wedge B probably developed duringthe sea-level fall ending with substage 18.2.

Sediments associated with major (fourth-order)unconformities were arguably deposited duringthe most pronounced deglaciations and interglacialstages (e.g. MIS 21, 19, 17.3, 15.5). The knownrapidity of the corresponding transgressions is con-firmed by the general lack of backstepping patterns.

Other indirect lines of evidence, independent ofthe above data, suggest that wedge progradationtook place during the stages of sea-level fall. Thewedges are identified as strike-fed coastal litho-somes developed in a high-energy, storm-dominatedwave climate characterized by a high efficiency ofalong-shore redistribution of sediments. Actually,frequency of storms tends to be higher during falland lowstand (Einsele, 1993), and wave-dominatedsand bodies pointing to linear sources are regardedby Trincardi and Field (1991), Miall (1997) andChiocci et al. (1997) as typical of shelf-perchedfalling-stage and lowstand shelf-margin deposits.

The large volumetric predominance of the sandstored within the prograding wedges with respect tosediments involved in other systems tracts is consis-


tent with the statement of Hays et al. (1976), whofound that, for Pleistocene 100-ka cycles, the sea-level fall occupied 8590% of the total cycle period.Actually, Pleistocene successions are volumetricallydominated by falling-stage and lowstand deposits,whereas the available accommodation volume forHST sedimentation is limited (see also Field andTrincardi, 1991; Thorne and Swift, 1991; Chiocciet al., 1997; Somoza et al., 1997; Trincardi andCorreggiari, 1999).

The progradation potential of highly bioclasticforamol-type units, typical of wedge A, may havebeen enhanced during the falling stage due to higheropportunity of multiple reworking and redeposition(Henrich et al., 1995; Simone, 1996), provided byenhancement of storm activity during the glacialtime (Einsele, 1993; Galloway and Hobday, 1996;Chiocci and Orlando, 1996) and possibly increasedrate of carbonate production.

6. Origin of higher-order cycles

A number of hypotheses may be examined forthe origin of higher-order cycles. Authigenic mecha-nisms are generally defined as intrinsic to sedimenta-tion in a given depositional system: the typical caseis the deltaic setting, where cyclicity may arise fromrepeated switching of input points of terrigenoussediment. We believe that such a setting, and con-sequently the incidence of authigenic controls, maybe ruled out, as we argued above that progradationtook place from a line source, and developed in ahigh-energy wave climate resulting in active along-shore redistribution of sediments and straighteningof the coast. In addition, the length of the shore-line was limited by the geometry of the S. Maurosub-basin, which was a relatively narrow corridorbounded by structural highs. Furthermore, it shouldnot be forgotten that the depositional system wasnot strictly siliciclastic, as in some shingled units theintrabasinal biogenic sediment is predominant.

Although short-term pulsating tectonic events(10100,000 yr) may significantly affect sedimen-tation processes (Peper et al., 1992), the incidenceof such a mechanism is regarded as improbable inthe origin of higher-order cycles, considering thatfacies associations tend to regularly succeed one

another downdip through repeated and predictablecycles of deposition, and that the amplitude of rela-tive sea-level changes recorded by small-scale cyclesis larger than that of commonly observed tectonicallyinduced motions. Differential load-driven subsidencewas certainly active, but in the absence of growthfaults it is difficult to imagine a pulsating effect.

Changes in the rate of sediment supply are largelycontrolled by environmental factors such as re-lief, climate and drainage of the hinterland. Thesechanges generally lead to variations in accommo-dation comparable to those produced by sea-levelfluctuations, as stressed by Schlager (1993), and, inprinciple, transgressive events may result from sig-nificant decreases in sediment supply rates. However,the falling-stage systems tracts of shingled units can-not be produced by changes in supply regime. Theyrequire relative falls in sea level that are faster thanthe long-term subsidence (Schlager, 1993).

Especially during Pleistocene times postdatingMIS 25, the onset and developments of glacial con-ditions were characterized by superimposed higher-order perturbations, as indicated by the sawtoothpattern of the relative limbs of the oxygen-isotoperecord (e.g. Imbrie et al., 1984). Although it is gen-erally agreed that the oxygen-isotope record is nota linear function of sea level (Shackleton, 1987), itis however largely recognized, at least for the lastgrowth of continental ice sheets, that sea-level fallwas punctuated by a number of minor stillstandsand interstadial reversals, as shown by data of raisedmarine terraces (Mesolella et al., 1969; Bloom et al.,1974; Dodge et al., 1983) and seismic analysis ofsome margins (e.g. Somoza et al., 1997).

In conclusion, although concomitant causes ofdifferent nature may have interacted, it is temptingto ascribe the generation of the small-scale cyclic-ity to minor eustatic changes punctuating long-lived,erratic falling stages, possibly accompanied by cli-mate-driven fluctuations of supply.

7. Factors controlling geometry, internalorganization and preservation of progradingunits

The sedimentary record of the S. Mauro sub-basinis clearly influenced by differential structural growth,


Fig. 12. Outline of stratal architecture of lower composite wedge in NE part of study area, illustrating role of oversteepened shelfgradients generated by syndepositional tectonics and collapse scars in controlling direction of progradation (approximate scale in centre).

causing pronounced variations in accommodation,bathymetry and gradients in the shelf and nearshoreareas, and strongly modulating the stratal and faciespatterns of the prograding wedges (Figs. 2 and 9c).Actually, the cycles and their component units showthicknesses and degree of preservation dependingon variable accommodation space allowed by syn-depositional tectonics. However, they fail to showsignificantly contrasting sedimentation patterns.

Sedimentation took place within the narrow fault-bounded S. Mauro sub-basin. This confined setting,together with a high rate of sediment influx, couldexplain the large extent of wedge progradation.

Abnormal submarine topographic gradients onthe flanks of growing folds or near-boundary faultsinfluenced progradation directions (Fig. 12) and con-strained the progradation into rapidly deepening wa-ters, leading to relatively high clinoform dips, up to16 (Fig. 9d). Steep clinoform angles (up to morethan 30) are reported in the literature as a responseto the steep gradient of the substrate, especially inthe case of tectonic control of sedimentation (Kampand Nelson, 1987; Kamp et al., 1988; Obrador et al.,1992; Laptas, 1992; Hanken et al., 1996).

Syndepositional tectonics partly controlled the na-ture of the basal contacts (abrupt vs. gradational) of

clinoform packages, sometimes also changing down-lap contacts into contacts of apparent onlap. Tectonicoversteepening of shelf gradients may have alsofavoured gravity detachment processes, leading tocollapse scars on the flanks of growing folds andnear boundary faults (Fig. 12).

The preservation potential of forced-regressivewedges depends on conditions preventing cannibal-ization of the deposits which formed in the earlystages of relative sea-level fall and limiting the depthof erosion due to shoreface retreat during transgres-sive events. Generally, preservation is regarded aspossible only where depressions, steep gradients ormorphologic steps are present in the shelf surfaceand subsidence rate is sufficiently high (Trincardiand Field, 1991; Field and Trincardi, 1991; Saito,1991; Chiocci and Orlando, 1996). In our study area,the preservation of falling-stage units was essentiallydue to the creation of sediment sinks as a result ofthe growth of gentle synclines, coupled with a rela-tively high rate of regional subsidence, high rate ofsediment influx, and sediment compaction. Anothercritical factor is represented by the high asymme-try of the relative sea-level curve, with long-lasting,stepwise falls emplacing large volumes of sediment,and extremely rapid rises (Trincardi and Correggiari,


1999). A high rate and short duration of relativesea-level rise during major transgressive episodes,enhanced by a relatively high subsidence rate, cer-tainly prevented strong erosion and reworking, sothat most of the prograding units remained belowthe level of subsequent erosion. Areas affected bythe highest subsidence rate could also escape emer-gence at the end of the falling-stage progradation.This for instance may be documented in the Valle diManche section, where a ravinement surface at thetop of the lower composite wedge is lacking and isreplaced by a conformable drowning surface.

Of all the above concurrent causes favouring thepreservation of falling-stage and lowstand units themost critical factor is certainly the structural control,as stressed by Chiocci et al. (1997). A comparisonof the Pleistocene records of the S. Mauro sub-basinand Wanganui Basin (New Zealand) (Kamp andTurner, 1990; Carter et al., 1991) is illustrative ofthe importance of this control. Due to the low ratesof subsidence of the shelf area, the Wanganui Basinshows an onshore stratigraphic record dominated byshallow-water transgressive and highstand deposits,and characterized by large stratigraphic gaps duringthe stages of sea-level fall and lowstand. On theother hand, a series of prograding clinoform wedgesdeveloped during glacial stages at the shelf margin.

8. Other examples of prograding PlioPleistoceneunits with high bioclastic content in theMediterranean area

Prograding wedges with similar characteristics tothose described above, and particularly with highbioclastic content, have been observed in other sitesof the Crotone basin, and are relatively common inthe Upper Pliocene to Pleistocene of southern Italy,Sicily and islands in the Mediterranean, particularlyin falling-stage and lowstand systems tracts. Theyhave been reported in the Apulian foreland of theApennines (DAlessandro and Massari, 1997; Pomarand Tropeano, 1998), in the Caltanissetta basin ofSicily (Catalano et al., 1992; Vitale, 1996; Likorishand Butler, 1996; Vitale, 1998) and in the coastalgrabens of Rhodes, Greece (Hanken et al., 1996).

In most of the above examples, the wedgesare attached to structural highs and prograde with

high-angle clinoforms on to a steep-gradient sub-strate, commonly subject to syndepositional defor-mation. Skeletal material is copiously produced innearby shoreface platforms and then dispersed, es-sentially by storm-driven offshore-directed flows,and deposited on the prograding front. The unitsmay generally be correlated over large areas, even insettings characterized by high tectonic activity.

Similar observations derive from seismic dataconcerning falling-stage and lowstand downlappingsedimentary units existing along the MediterraneanSea margins (Trincardi and Field, 1991; Chiocci,1994; Chiocci and Orlando, 1996; Chiocci et al.,1997; Chiocci and Romagnoli, 1999). These unitshave consistently offshore-dipping bedding surfaces,a composition dominated by intrabasinal sediments,and a good lateral along-slope continuity, pointing toprogradation from a line-source.

It is therefore suggested that, in the presence ofsuitable conditions of high rates of subsidence andsediment supply, prograding units of this kind are atypical element of the falling and lowstand systemstracts of PlioPleistocene glacio-eustatic cycles inthe Mediterranean area.

9. Conclusions

A number of conclusions stem from the aboveanalysis.

(1) The Pleistocene infill of the small S. Maurosub-basin (southern Italy) shows a clear cyclicity andmostly consists of prograding coastal sandgravelwedges with clinoform geometry, locally highly bio-clastic (skeletal, foramol-type carbonates), separatedby major unconformities recording major transgres-sive episodes. On the basis of bio-magnetostratigra-phy the cycles in the lower part of the successionare correlated to the standard oxygen-isotope record(Rio et al., 1996), and, in spite of active synde-positional tectonics, they can be demonstrated tobe genetically related to Pleistocene fourth-orderhigh-amplitude sea-level oscillations. Two of theprograding wedges show composite internal archi-tecture. The older one built out during the majorclimatic transition and related sea-level fall whichoccurred from MIS 25 to MIS 22 (Rio et al., 1996).The younger wedge most probably developed dur-


ing the sea-level fall that culminated with substage18.2.

(2) The composite wedges consist of shingledunits bounded by seaward-dipping surfaces with asigmoid clinoform geometry which represent ravine-ment surfaces updip, and conformable flooding sur-faces downdip. Within individual shingles, an early,relatively thin package of sigmoid clinoforms record-ing short-lived progradation accompanied by slightlandward encroachment of coastal onlap, is fol-lowed by a volumetrically dominant package ofoblique-tangential clinoforms with toplap termina-tions, physically attached to the former, recordingthe basinward and downward displacement of theshoreline. The wedges are thus organized into high-frequency, small-scale depositional sequences, eachcomprising transgressive, highstand and falling-stagesystems tracts.

(3) The prograding units developed in a high-energy wave climate. The dominant processes wererepresented by highly efficient longshore drift, re-working of sediments in the topset shoreface by re-current storm-driven offshore flows following coastalsetup, and gravity resedimentation on to the fore-set slope of prograding bodies. Given this set-ting, we can reasonably assume that accretionaryforced regressions occurred along the entire shore-line and originated coastal prograding bodies. Inten-sified storm mixing during glacial periods, and theresulting well-oxygenated conditions over the shelfmay have enhanced the rates of productivity andthe progradation potential of skeletal, foramol-typecarbonates.

(4) Concerning the origin of the small-scalecyclicity, authigenic mechanisms linked to shift ofsediment input points seem to be excluded by theabove setting. Although the concomitance of dif-ferent controlling factors cannot be excluded, it istempting to ascribe the generation of the small-scalecyclicity to minor eustatic changes punctuating long-lived, erratic falling stages, possibly accompanied byclimate-driven fluctuations of supply.

(5) The syndepositional growth of synclines, cou-pled with a relatively high regional subsidence, ex-erted a critical influence on the preservation potentialof falling-stage units.

(6) Comparable Upper Pliocene to Pleistoceneshelf-perched and shelf-edge strike-oriented pro-

grading units, commonly with high contents offoramol-type skeletal carbonates, are known in sev-eral Mediterranean areas, both on land and on mod-ern margins, suggesting that they are a typical el-ement of the falling and lowstand systems tractsof PlioPleistocene glacio-eustatic cycles in theseareas.

Acknowledgements

Helpful critical suggestions concerning some as-pects of the manuscript were provided by F. Chiocci.To Tim Naish, Fabio Trincardi and an anonymousreferee I owe important reviews of the manuscript.I am particularly indebted to A. Miall for his pos-itive comments, editing work, and kind support. S.Castelli is acknowledged for careful photographicwork, N. Michelon and F. Todesco for accurate exe-cution of drawings, and Gabriel Walton for revisionof the English text. Financial support was providedby the Italian Ministry of University and Scien-tific Research, grant 40%. This is contribution 1 ofthe National MURST Project Interazioni clima, eu-statismo e tettonica nella sedimentazione: il caso delQuaternario italiano e confronti con altri intervalli edaree (principal investigator D. Rio).

Appendix A

A.1. Bioclastic units of the lower composite wedge

The macrobenthic material of richly bioclastic units in thelower composite wedge consists of three types of components.

(i) Mud-related or mixed-related faunal elements predom-inantly disarticulated, broken (commonly with smoothed frac-tures), abraded, and partly bioeroded (Entobia, Maeandropoly-dora, algal borings) or encrusted by celleporiform or laminarbryozoa, red algae or tubeworms. The following species havebeen recognized: Dentalium rectum, Nucula nucleus, Pectenjacobaeus, Glans aculeata, Cerithium varicosum, Xenophoracrispa, Nassarius prismaticus, N. cabrierensis, N. serraticosta,Caryophyllia sp., Pseudamussium septemradiatum, Pododesmusglaucus, Neopycnodonte sp., Astarte sulcata, Glossus humanus,Aporrhais serresianus, Phalium laevigatum, Ranella olearia,Fusinus rostratus, Arca tetragona, Limopsis, Turritella tricar-inata pliorecens, Turritella turbona, Alvania cimicoides, Ga-leodea echinophora, Trophon muricatus, Flabellum sp. Bio-coenotic characters indicate circalittoral and sometimes alsoepibathyal (Aporrhais serresianus, Ranella olearia) biotopes.


They are regarded as non-coeval, as their preservational stateand taphonomic signature indicate exhumation after burial andreworking in a high-energy, shallow-water environment, con-trasting with their biocoenotic characters indicating circalittoraland sometimes also epibathyal biotopes. They form a skeletallag particularly abundant in close proximity to the Scandaleboundary fault, active during sedimentation, where they marksignificant erosion of the substrate.

(ii) Parautochthonous components showing variable stateof preservation, fragmentation and abrasion, but usually onlyslightly or not abraded. The following species have been rec-ognized: Diplodonta apicalis, Pteromeris corbis, Digitaria digi-taria, Gonilia calliglipta, Goodallia triangularis, Plagiocardiumpapillosum, Gibbula magus, Echinocyamus pusillus, Chlamysvaria, Glycymeris glycymeris, Astarte fusca, Venus casina,Clausinella fasciata. Shells are generally disarticulated, some-times articulated (closed or semi-closed), occasionally encrustedby bryozoa. Elements of this group most probably settled inthe infralittoral zone. Although partly exhumed and worked bycurrents and waves, they are thought not to have been eventuallytransported outside their original biotope.

(iii) Allochthonous components, typical of infralittoral bio-coenoses settling on substrates ranging from mixed to sandy andeven rocky (e.g. Chama). The following species have been recog-nized: Chama gryphoides, Arctica islandica, Aporrhais pespele-cani, Acanthocardia tuberculata, Spisula subtruncata, Panopeaglycymeris, Calliostoma conulus, Homalopoma sanguineum, Bit-tium reticulatum, Rissoa monodonta, Rissoa variabilis, Alvaniacancellata, Caecum trachea, Tornus subcarinatus, Monophorusperversus, Chlamys multistriata, Corbula gibba, Cerithium vul-gatum, Trochidae. Skeletals are in all states of abrasion andfragmentation, commonly bioeroded (Entobia, Oichnus) and en-crusted (bryozoa, red algae, polychaetes). These elements, al-though presumably coeval, are thought to have been exhumedand repeatedly reworked in a high-energy environment, and latertransported outside their original biotope.

Skeletal assemblages appear ecologically mixed, with theimprints of various taphonomic processes, depending on sourceand history of the shells, reworking and seafloor exposure. Anabundance of abraded and fragmented shells attests to initialresidence above the fair-weather wave base before the latertransport and redeposition. The non-coeval (lag) component isalways significant and probably derives from erosion of thehighly bioclastic bed packages of Cutro 2. Exhumation anderosion of older elements are also documented by the localpresence of reworked early-cemented Thalassinoides burrowsbored by Maeandropolydora spp., Caulostrepsis cretacea andsmall Gastrochaenolites isp., and encrusted by laminar bryozoa.

A.2. Coarse fossiliferous deposits blanketing unconformitysurfaces between shingled units of composite wedges

The skeletals show taphonomically complex histories and mayinclude in the same assemblage autochthonous, parautochthonousand allochthonous elements. Evidence of storm-related blanket-ing followed by exhumation and encrustation=bio-erosion maysometimes be found. In one case, rapid burial of Glycymeris

bimaculata, Modiola sericea, Aequipecten opercularis and Arc-tica islandica all with valves unworn, partly still articulated andclosed, was followed by exhumation. Later, the exhumed shellswere encrusted by epibionts like Anomia ephippium and Podo-desmus patelliformis.

References

Abbott, S.T., 1997. Foraminiferal paleobathymetry and mid-cyclearchitecture of Mid-Pleistocene depositional sequences, Wan-ganui Basin, New Zealand. Palaios 12, 267281.

Abbott, S.T., Carter, R.M., 1994. The sequence architectureof mid-Pleistocene (0.350.95 Ma) cyclothems from NewZealand: facies development during a period of orbital controlon sea-level cyclicity. In: de Boer, P.L., Smith, D.G. (Eds.),Orbital Forcing and Cyclic Sequences. Int. Assoc. Sedimen-tol., Spec. Publ. 19, 367394.

Abbott, S.T., Carter, R.M., 1997. Macrofossil associations fromMid-Pleistocene cyclothems, Castlecliff section, New Zealand:implications for sequence stratigraphy. Palaios 12, 188210.

Ainsworth, R.B., Pattinson, S.A.J., 1994. Where have all thelowstands gone? Evidence for attached systems tracts in theWestern Interior of North America. Geology 22, 415418.

Aksu, A.E., Ulug, A., Piper, D.J.W., Konuk, Y.T., Turgut, S.,1992. Quaternary sedimentary history of Adana, Cilicia andIskenderun Basins: northeast Mediterranean Sea. Mar. Geol.104, 5571.

Bassinot, F.C., Labeyrie, L.D., Vincent, E., Quidelleur, X.,Shackleton, N.J., Lancelot, Y., 1994. The astronomical theoryof climate and the age of the BrunhesMatuyama magneticreversal. Earth Planet. Sci. Lett. 126, 91108.

Berggren, W.A., Hilgen, F.J., Langereis, C.G., Kent, D.V.,Obradovich, J.D., Raffi, I., Raymo, M.E., Shackleton, N.J.,1995. Late Neogene chronology: new perspectives in high-res-olution stratigraphy. Geol. Soc. Am. Bull. 107, 12721287.

Bloom, A.L., Broecker, W.S., Chappell, J.M.A., Matthews, R.K.,Mesolella, K.J., 1974. Quaternary sea-level fluctuations on atectonic coast: new 230Th=234U dates from the Huon Penin-sula, New Guinea. Quat. Res. 4, 185205.

Broecker, W.S., 1984. Terminations. In: Berger, A.L., Imbrie, J.,Hays, J., Kukla, G., Saltzman, B. (Eds.), Milankovitch andClimate, Part 2. Plenum Reidel, Norwell, MA, pp. 687698.

Broecker, W.S., van Donk, J., 1970. Insolation changes, icevolumes and the 18O record in deep-sea cores. Rev. Geophys.8, 169198.

Carter, R.M., Abbott, S.T., Fulthorpe, C.S., Haywick, D.W.,Henderson, R.A., 1991. Application of global sea-level andsequence-stratigraphic models in southern hemisphere Neo-gene strata from New Zealand. In: Macdonald, D.I.M. (Ed.)Sedimentation, Tectonics and Eustasy: Sea Level Changes atActive Margins. Int. Assoc. Sedimentol., Spec. Publ. 12, 4165.

Catalano, R., Di Stefano, E., Lo Cicero, G., Vail, P.R., Vitale,F.P., 1992. Pliocene sequence stratigraphy of the CaltanissettaBasin (Capodarso section, Sicily). Sequence stratigraphy ofEuropean Basins, Int. Congr., Dijon, Abstr. Volume, p. 438.


Chiocci, F.L., 1994. Very high-resolution seismics as a tool forsequence stratigraphy applied to outcrop-scale examplesfrom the eastern Tyrrhenian margin Holocene=Pleistocene de-posits. Am. Assoc. Pet. Soc. Bull. 78, 378395.

Chiocci, F., Orlando, L., 1996. Lowstand terraces on TyrrhenianSea steep continental slopes. Mar. Geol. 134, 127143.

Chiocci, F.L., Romagnoli, C., 1999. Terrazzi deposizionali nelleIsole Eolie. In: Chiocci, F.L., DAngelo, S., Romagnoli, C.(Eds.), Atlante dei Terrazzi Deposizionali Sommersi lungo leCoste Italiane. Memorie descrittive della Carta Geol. dItalia,Roma (in press).

Chiocci, F., Ercilla, G., Torres, J., 1997. Stratal architecture ofwestern Mediterranean margins as the result of the stackingof Quaternary lowstand deposits below glacio-eustatic fluctu-ation base-level. Sediment. Geol. 112, 195217.

Christie-Blick, N., 1991. Onlap, offlap, and the origin of uncon-formity-bounded depositional sequences. Mar. Geol. 97, 3556.

Cosentino, D., Gliozzi, E., Salvini, F., 1989. Brittle deformationsin the Upper Pleistocene deposits of the Crotone Peninsula,Calabria, southern Italy. Tectonophysics 163, 205217.

DAlessandro, A., Massari, F., 1997. Pliocene and Pleistocenedepositional environments in the Pesculuse area (Salento,Italy). Riv. Ital. Paleontol. Stratigr. 103, 221258.

Dodge, R.E., Fairbanks, R.G., Benninger, L.K., Maurrasse, F.,1983. Pleistocene sea levels from raised coral reefs of Haiti.Science 219, 14231425.

Dominguez, J.M.L., Bittencourt, A.C.S.P., Martin, L., 1992. Con-trols on Quaternary coastal evolution of the east-northeasterncoast of Brazil: roles of sea-level history, trade winds andclimate. Sediment. Geol. 80, 213232.

Einsele, G., 1993. Marine depositional events controlled by sed-iment supply and sea-level changes. Geol. Rundsch. 82, 173184.

Ellis, P.G., McClay, K.R., 1988. Listric extensional systems:results of analogue model experiments. Basin Res. 1, 5570.

Field, M.E., Trincardi, F., 1991. Regressive coastal deposits onQuaternary continental shelves: preservation and legacy. In:Osborne, R.H. (Ed.), From Shoreline to Abyss: F.P. ShepardCommemorative Volume. Spec. Publ. Soc. Econ. Paleontol.Mineral. 46, 107122.

Galloway, W.E., Hobday, D.K., 1996. Terrigenous Clastic Depo-sitional Systems. Springer, New York, 489 pp.

Gawthorpe, R.L., Sharp, I., Underhill, J.R., Gupta, S., 1997.Linked sequence stratigraphic and structural evolution of prop-agating normal faults. Geology 25, 795798.

Gibbs, A.D., 1984. Structural evolution of extensional basinmargins. J. Geol. Soc. London 141, 609620.

Gliozzi, E., 1987. I terrazzi del Pleistocene superiore dellapenisola di Crotone (Calabria). Geol. Rom. 26, 1779.

Hanken, N.-M., Bromley, R.G., Miller, J., 1996. Plio-Pleistocenesedimentation in coastal grabens, north-east Rhodes, Greece.Geol. J. 31, 271296.

Hays, J.D., Imbrie, J., Shackleton, N.J., 1976. Variations in theearths orbit: pacemaker of the ice ages. Science 194, 11211132.

Helland-Hansen, W., 1993. Geometry and facies of Tertiaryclinothems, Spitsbergen. Sedimentology 39, 10131029.

Helland-Hansen, W., Gjelberg, J.G., 1994. Conceptual basis andvariability in sequence stratigraphy: a different perspective.Sediment. Geol. 92, 3152.

Henrich, R., Freiwald, A., Betzler, C., Bader, B., Schafer, P.,Samtleben, C., Brachert, T.C., Wehrmann, A., Zankl, H.,Kuhlmann, D.H.H., 1995. Controls on modern carbonate sed-imentation on warm-temperate to Arctic coasts, shelves andseamounts in the northern hemisphere: implications for fossilcounterparts. Facies 32, 71108.

Hernandez-Molina, F.J., Somoza, L., Fernandez-Salas, L.M.,Lobo, F., Llave, E., Roque, C., 1998. Late Holocene infralit-toral wedge: a large scale progradational lithosome in shallowmarine environments. 15th Int. Sedimentol. Congr., Alicante,Abstr. Book, pp. 421422.

Hunt, D., Tucker, M.E., 1992. Stranded parasequences and theforced regressive wedge systems tract: deposition during base-level fall. Sediment. Geol. 81, 19.

Hunt, D., Tucker, M.E., 1995. Stranded parasequences and forcedregressive wedge systems tract: deposition during base-levelfall reply. Sediment. Geol. 95, 147160.

Imbrie, J., Hays, J.D., Martinson, G.D., McIntyre, A., Mix,A.C., Morley, J.J., Pisias, N.G., Prell, W.L., Shackleton, N.J.,1984. The orbital theory of Pleistocene climate: support froma revised chronology of the marine 18O record. In: Berger,A.L., Imbrie, J., Hays, J., Kukla, G., Saltzman, B. (Eds.),Milankovitch and Climate, Part 1. Plenum Reidel, Norwell,MA, pp. 269305.

Kamp, P.J.J., Nelson, C.S., 1987. Tectonic and sea-level controlson nontropical Neogene limestones in New Zealand. Geology15, 610613.

Kamp, P.J.J., Turner, G.M., 1990. Pleistocene unconformity-bounded shelf sequences (Wanganui Basin, New Zealand)correlated with global isotope record. Sediment. Geol. 68,155161.

Kamp, P.J.J., Harmsen, F.J., Nelson, C.S., Boyle, S.F., 1988.Barnacle-dominated limestone with giant cross-beds in a non-tropical, tide-swept, Pliocene forearc seaway, Hawkes Bay,New Zealand. Sediment. Geol. 60, 173195.

Kidwell, S.M., 1991. The stratigraphy of shell concentrations. In:Allison, P.A., Briggs, D.E.G. (Eds.), Taphonomy: Releasingthe Data Locked in the Fossil Record. Topics in Geobiology,Vol. 9, Plenum, New York, pp. 211290.

Laptas, A., 1992. Giant-scale cross-bedded Miocene biocalcaren-ites in the northern margin of the Carpathian foredeep. Ann.Soc. Geol. Pol. 62, 149167.

Likorish, W.H., Butler, R.W.H., 1996. Fold amplification andparasequence stacking patterns in syntectonic shoreface car-bonates. Geol. Soc. Am. Bull. 108, 966977.

Massari, F., 1996. Abundance in upper flow-regime stratificationtypes on steep-face coarse-grained Gilbert-type progradationalwedges (Pleistocene of southern Italy). J. Sediment. Res. 66,364375.

Mellere, D., Steel, R., 1995. Variability of lowstand wedgesand their distinction from forced-regressive wedges in theMesaverde Group, southeast Wyoming. Geology 23, 803806.


Mesolella, K.J., Matthews, R.K., Broecker, W.S., Thurber, D.L.,1969. The astronomical theory of climatic change: Barbadosdata. J. Geol. 77, 250274.

Miall, A.D., 1997. The Geology of Stratigraphic Sequences.Springer, New York, 433 pp.

Naish, T., Kamp, P.J.J., 1997. Sequence stratigraphy of sixth-order (41 k.y.) PliocenePleistocene cyclothems, Wanganuibasin, New Zealand: a case for the regressive systems tract.Geol. Soc. Am. Bull. 109, 978999.

Obrador, A., Pomar, L., Taberner, C., 1992. Late Miocene brecciaof Menorca (Balearic Islands): a basis for the interpretation ofa Neogene ramp deposit. Sediment. Geol. 79, 203223.

Palmentola, G., Carobene, L., Mastronuzzi, G., Sanso`, P., 1990.I terrazzi marini Pleistocenici della Penisola di Crotone (Cal-abria). Geogr. Fis. Dinam. Quat., Comitato Glaciol. Ital. 13,7580.

Peper, T., Beeckman, F., Cloetingh, S., 1992. Consequences ofthrusting and intraplate stress fluctuations for vertical motionsin foreland basins and peripheral areas. Geophys. J. Int. 111,104126.

Piper, D.J.W., Perissoratis, C., 1990. Effects of Quaternarysea level change on a rapidly subsiding deltaic shelf, northAegean, Greece. 13th Int. Sedimentol. Congr., Nottingham,Abstr. Book, pp. 425426.

Piper, D.J.W., Perissoratis, C., 1991. Late Quaternary sedimen-tation on the north Aegean continental margin, Greece. Am.Assoc. Pet. Geol. Bull. 75, 4661.

Plint, A.G., 1988. Sharp-based shoreface parasequences and off-shore bars in the Cardium formation of Alberta; their rela-tionship to relative changes in sea level. In: Wilgus, C.K.,Hastings, B.S., Kendall, C.G.St.C., Posamentier, H.W., Ross,C.A., Van Wagoner, J.C. (Eds.), Sea-Level Changes: An Inte-grated Approach. Soc. Econ. Paleontol. Mineral., Spec. Publ.42, 357370.

Plint, A.G., 1991. High-frequency relative sea-level oscillationsin the Upper Cretaceous shelf clastics of the Alberta forelandbasin: possible evidence for glacio-eustatic control? In: Mac-donald, D.I.M. (Ed.) Sedimentation, Tectonics and Eustasy.Int. Assoc. Sedimentol., Spec. Publ. 12, 409428.

Pomar, L., Tropeano, M., 1998. Insights for large-scalecross-bedded sandstones encased in offshore deposits: theCalcarenite di Gravina, in Matera (southern Italy). In:Canaveras, J.C., Garcia del Cura, M.A., Soria, J. (Eds.), 15thInt. Sedimentol. Congr., Alicante, April, Abstr. Book, pp. 631633.

Posamentier, H.W., Allen, G.P., James, D.P., Tesson, M., 1992.Forced regressions in a sequence stratigraphic framework:concepts, examples, and exploration significance. Am. Assoc.Pet. Geol. Bull. 76, 16871709.

Prell, W.L., 1982. Oxygen and carbon isotopic stratigraphy forthe Quaternary of Hole 502B: evidence for two modes ofisotopic variability. Init. Rep. DSDP 68, 455464.

Raymo, M.E., 1997. The timing of major climate terminations.Paleoceanography 12, 577585.

Rio, D., Channell, J.E.T., Massari, F., Poli, M.S., Sgavetti, M.,DAlessandro, A., Prosser, G., 1996. Reading Pleistocene eu-

stasy in a tectonically active siliciclastic shelf setting (Crotonepeninsula, southern Italy). Geology 24, 743746.

Ruddiman, W.F., Raymo, M.E., Martinson, D.G., Clement, D.M.,Backman, J., 1989. Pleistocene evolution: Northern Hemi-sphere ice sheets and North Atlantic Ocean. Paleoceanography4, 353412.

Saito, Y., 1991. Sequence stratigraphy on the shelf and upperslope in response to the latest PleistoceneHolocene sea-levelchanges off Sendai, northeast Japan. Int. Assoc. Sedimentol.Spec. Publ. 12, 133150.

Scheepers, P.J.J., 1994. Tectonic rotations in the Tyrrhenianarc system during the Quaternary and Late Tertiary. Geol.Ultraiect., Meded. Fac. Aardkd. Univ. Utrecht 112, 350 pp.

Schlager, W., 1993. Accommodation and supply a dual con-trol on stratigraphic sequences. Sediment. Geol. 86, 111136.

Shackleton, N.J., 1987. Oxygen isotopes, ice volume and sealevel. Quat. Sci. Rev. 6, 183190.

Simone, L., 1996. Le piattaforme carbonatiche tropicali: limitie problemi di un modello sovrautilizzato. Riunione GruppoSedim. del CNR, Catania, 1014 October 1996, Catania, pp.245249.

Somoza, L., Hernandez-Molina, F.J., De Andres, J.R., Rey, J.,1997. Continental shelf architecture and sea-level cycles: LateQuaternary high-resolution stratigraphy of the Gulf of Cadiz,Spain. Geo-Mar. Lett. 17, 133139.

Tesson, M., Allen, G.P., Ravenne, C., 1993. Late Pleistoceneshelf-perched lowstand wedges on the Rhone continental shelf.In: Posamentier, H.W., Summerhayes, C.P., Haq B.U., Allen,G.P. (Eds.), Sequence Stratigraphy and Facies Associations.Int. Assoc. Sedimentol., Spec. Publ. 18, 183196.

Thierstein, H.R., Geitzenauer, K.R., Molfino, B., 1977. Globalsynchroneity of late Quaternary coccolith datum levels: vali-dation by oxygen isotopes. Geology 5, 400404.

Thorne, J.A., Swift, D.J.P., 1991. Sedimentation on continentalmargins, II. Application of the regime concept. In: Swift,D.J.P., Oertel, G.F., Tillman, R.W., Thorne, J.A. (Eds.), ShelfSand and Sandstone Bodies, Geometry, Facies, and SequenceStratigraphy. Int. Assoc. Sedimentol., Spec. Publ. 14, 3358.

Trincardi, F., Correggiari, A., 1999. Quaternary forced-regressiondeposits in the Adriatic Basin and the record of composite sea-level cycles. In: Hunt, D., Gawthorpe, R. (Eds.), SedimentaryResponses to Forced Regressions. Geol. Soc. London, Spec.Publ. (in press).

Trincardi, F., Field, M.E., 1991. Geometry, lateral variation, andpreservation of downlapping regressive shelf deposits: easternTyrrhenian Sea margin, Italy. J. Sediment. Petrol. 61, 775790.

Trincardi, F., Cattaneo, A., Asioli, A., Correggiari, A., Lan-gone, L., 1996. Stratigraphy of the late-Quaternary depositsin the central Adriatic basin and the record of short-termclimatic events. In: Guilizzoni, P., Oldfield, F. (Guest Eds.),Palaeoenvironmental Analysis of Italian Crater Lake and Adri-atic Sediments. Mem. Ist. Ital. Idrobiol. 55, 3970.

Van Dijk, J.P., 1991. Basin dynamics and sequence stratigraphyin the Calabrian Arc (Central Mediterranean); records andpathways of the Crotone Basin. Geol. Mijnbouw 70, 187201.

Van Dijk, J.P., 1994. Late Neogene kinematics of intra-arc


oblique shear-zone: the PetiliaRizzuto fault zone (CalabrianArc, Central Mediterranean). Tectonics 13, 12011230.

Vitale, F.P., 1996. I bacini Plio-Pleistocenici della Sicilia: unlaboratorio naturale per lo studio delle interazioni tra tettonicae glacio-eustatismo. In: Colella, A. (Ed.), Riunione GruppoSedim. del CNR, Catania, 1014 October, Guida alle escur-sioni, Catania, pp. 59116.

Vitale, F.P., 1998. Stacking patterns and tectonics: field evidence

from Pliocene growth folds of Sicily (Central Mediterranean).Soc. Econ. Paleontol. Mineral., Spec. Publ. 60, 181199.

Walker, R.G., Plint, A.G., 1992. Wave- and storm-dominatedshallow marine systems. In: Walker, R.G., James, N.P. (Eds.),Facies Models: Responses to Sea Level Changes. GeologicalAssociation of Canada, Toronto, pp. 219238.

Xiao, H., Suppe, J., 1992. Origin of rollover. Am. Assoc. Pet.Geol. Bull. 76, 509529.

Documents

Massari, F. Et Al., (1999). Composite Sedimentary Record of Falling Stages of Pleistocene Glacio-eustatic Cycles in a Shelf Setting (Crotone Basin, South Italy)