FROM RIFT TO DRIFT AND WEST-MEDITERRANEAN-TYRRHENIAN TECTONIC SETTING: A REVIEW

Carlo Savelli Consiglio Nazionale delle Ricerche, Istituto di Scienze del Mare, via P. Gobetti, 101, 40129, Bologna, ItalyE-mail address: carlo.savelli@bo.ismar.cnr.it

Pre-Oligocene, SE-directed flat subduction of European plate produced the submerged orogen of the West-Mediterranean-Tyrrhenian region. WNW-directed steep subduction of African plate accompanied the late Miocene-Recent oceanic opening of Tyrrhenian basin, eastern part of submerged orogen. Post-orogenic rift-related extension and calc-alkaline volcanism initiated in the Oligocene reached, in the Burdigalian, the stage of oceanic opening. In the Hercynian lithosphere of southern Europe and the western part of submerged orogen formed, respectively, the Sardinia-Provence and the north Algeria bathyal plains. During the Burdigalian, volcanism of calc-alkaline type has been widespread in the margins of the two oceanic basins. The late Miocene and late Pliocene drift episodes of the bathyal plains of Vavilov and Marsili occurred, on the contrary, when volcanism has been absent or scarce in the Tyrrhenian Sea margins. The contrast between abundance and lack of volcanism in the margins, at various times of rift-drift transition, is interpreted to indicate diversity of tectonic setting. In the Oligo-Burdigalian, drifting and calc-alkaline volcanism took place in the absence of subduction. The WNW-directed, steep subduction under the Tyrrhenian orogen commenced, probably, at 16/15 Ma (the waning of Burdigalian spreading). The space-time study indicates that calc-alkaline volcanism and extension are not linked only to subduction.

Subject terms: Geology Tectonics

Introduction

Extension tectonics and volcanism of Oligocene-Recent age of the West-Mediterranean-Tyrrhenian region are a consequence of the interactions between the European and African plates. Figure 1 shows that SE-directed flat-slab (Alpine-type) subduction of European plate has been replaced by WNW-directed steep-slab (Island-arc type) subduction of African plate. The former subduction led to the Mediterranean submerged orogen of Alpine age (OAA) in the Late Cretaceous-Eocene, and the latter produced basin opening and slab roll-back beneath the Maghrebid-Apennine wedging. The OAA extending from Alpine Corsica to the Betic cordillera (Fig. 2) was recognized as the westernmost branch of the western Alps related to the closure of the Mesozoic Alpine Tethys2, 3, 4, 5, 6. The slab beneath the south Tyrrhenian bathyal plain 7 is accompanied by release of 500 km deep seismic energy, high heat flow and positive gravity anomal. Regional lithosphere models indicate crustal thinning of <10 km and a 30 km LID. Various seafloor mineral deposits of hydrothermal origin are present, too8. Despite the young age, the West-Mediterranean-Tyrrhenian region was subject of various tectonic interpretations (see Supplementary Info S1).

Extension and magmatism commenced ca. 33/32 Ma (early Oligocene) in the OAA and the Hercynian lithosphere extending from Provence to Corsica-Sardinia. The extension reached the stage of consecutive emplacement of oceanic lithosphere in the Sardinia/Provence, north Algeria, Vavilov and Marsili basins (Fig. 1) during the last 20 Ma (Burdigalian - Recent). Overall, contin-ental margin block rotation produced asymmetric basin opening (Fig.1)9. The Sardinia-Provence and North Algeria basins are separated by the

Figure 1. Relief-shaded image of the west Mediterranean-Tyrrhenian area showing the Recent convergence fronts of the Maghreb-Apennines and Alpine belts, the pre-Oligocene front of subduction of the European plate beneath the extended orogen of Alpine age (OAA), and the oceanic basins of Sardinia-Provence (Sa-Pr b), Vavilov (V b), Marsili (M b) and north Algeria. The white arrows show the counter-clockwise rotation of Corsica-Sardinia and north Apennines, and the clockwise rotation of the Algeria margin and south Apennines. Legend: CTFZ = Catalan -Tunisian fracture zone separating the west segment of European lithosphere and extended OAA from that to the east (see text for discussion); CVZ = Catalan volcanic zone; GA = Gibraltar arc; RAF = Relict Alpine Front; TASZ = Trans-Alboran fracture zone; WSG = west Sardinia graben. The Algerian Maghreb magmatic sites: Or R = Ora-nois; Che = Cherchell; EA = East of Algiers; GK = Great Kabylia; LK = Little Kabylia; 41-P = 41° parallel frac-ture zone. The figure was created using the Plotmap cartographic software1.

major transcurrent structure known as the “north Balearic fracture zone” or the “Paul Fallot transform fault”) which dates back to the plate interactions of Hercynian age10. This structure ex-tending from the Catalan volcanic zone to the magmatic island of La Galite (Tunisian offshore) - hereafter called “Catalan-Tunisian fracture zone” - separates the western portion of the Mediter-ranean OAA and European lithosphere from that to the east. In particular, the fracture zone di-vides the Sardinia-Provence oceanic basin (European lithosphere) from the north Algerian basin (the western portion of the OAA), and this from the OAA portion that will see the Tyrrhenian opening. Another major lineation zone is found along the 41° parallel. It separates the north and south Tyrrhenian where thinned continental and oceanic lithosphere are rimmed by the the north and south Apennines which rotated counter-clockwise and clockwise, respectively11.

In the Earth Sciences, a generally accepted idea is that magmatism of calc-alkaline type results from partial melting of sources which underwent metasomatic modification via chemical recycling of subducted (mainly upper) crustal material. Though, the temporal interval between subduction and igneous manifestations is matter of debate. The pervasive presence of calc-alkaline volcanism above the zones of Recent plate convergence is probably at the origin of the tenet that melt uprising and metasomatism overlapped in time with subduction and metamorphism also in the geological past. On the other hand, the geological record suggests that calc-alkaline volcanism occurred, too, in rift setting far from subduction, which implicates that metasomatism and metamorphism took most likely place earlier than the eruptive activity. The temporal gap between the metasomatism linked to the tectonic mode of plate convergence and volcanism of calc-alkaline type can be highly variable. The episodes of oceanic basin opening and their space-time relationships with volcanism are re-examined to contribute to the debate pro or against the concomitance of subduction and calc-alkaline volcanism.

Because igneous petrology of magmatism is out of the scope, the datasets S4 and S6 are shown in the Supplementary material. Among the literature geochronology data of the West Mediterranean-Tyrrhenian region there can be some incorrectness because of the diverse quality of analysed material, and diversity of laboratories and analytical methods. However, dubious (few) ages can be tentatively pointed out by means of plausible temporal correlation among the re-examined large data set.

Volcanoclastic rocks showing calc-alkaline nature are widespread among the allochthounous sediments of the Apennines (Fig. 2; Supplementary Info S3 and Datasets S5, S6). If they have been produced from lost emission centres which were originally sited in the Tyrrhenian OAA, their space-time distribution can also be meaningful for the reconstruction of the link between calc-alkaline volcanism and tectonic setting. For the first time, allochthonous and “in-situ” volcanics have been jointly considered.

Figure 2. Distribution of “in situ” magmatics of the west Mediterranean, and allochthonous volcanoclastics of the Apennines. (A); Oligocene-Aquitanian (between ca. 33/32 and ca. 20 Ma): intrusives (red circle), volcanics (red triangle) and allochthonous volcanoclastics (elongated red triangle without rim shows presumed position; green

numbers in italics; see Suppl. dataset S4). Site 13: buried andesite volcano of the early Oligocene. White arrows: 1 = pre-Oligocene (> 33 Ma), SE-directed subduction beneath the orogen of Alpine Age (OAA); 2 = Post-Burdigalian (< 16 Ma), WNW-directed subduction of African lithosphere; this reconstruction considers that subduction was absent in the Oligocene - Burdigalian time. (B); Burdigalian (ca. 20 - 16 Ma): intrusives (black circle), volcanics (black triangle) and allochthonous volcanoclastics (elongated gray triangle); Langhian-Tortonian (between ca. 16 and 7.5 Ma): intrusives (yellow circle), volcanics (black rimmed yellow triangle) and allochthonous volcanoclastics (elongated yellow triangle). In the Burdigalian, calc-alkaline magmatism of andesitic and silicic type was accompanied by eruption of tholeiitic lavas and rifting reached the stage of oceanic spreading in the Sardinia-Provence basin to the east of the Catalan-Tunisian fracture zone (CTFZ; European plate), and north Algerian basin to the west. The scheme shows the inferred position of the WNW subduction hinge zone at ca. 6.3 (Vavilov opening) and 1.67 Ma (Marsili opening), the Apennine outcrops of the allochthonous volcanoclastic rocks, and the hypothetical sites of “lost” volcanic edifices and adjacent sedimentary lows which, according to the geodynamic interpretation (see Guerrera et alii, 1998, and Cibin et alii, 2001 in the Suppl. info), were originally sited in the Tyrrhenian OAA (offshore Sardinia-Corsica). Dotted line: the lithosphere-asthenosphere section of Fig. 7/A.

Figure 3. Shaded relief image of the Tyrrhenian seafloor; depths are colour-coded, illumination from the NW after multibeam bathymetric survey16 below 200 m waterdepth.The Tyrrhenian bathyal plains of Vavilov (V) and Marsili (M) reach depth of 3600 m (proper blue). Results

Episodes of oceanic opening

Burdigalian (ca. 20 – 16 Ma)Burdigalian (ca. 20 – 16 Ma)Post-collision, continental extension and calc-alkaline volcanism initiated in the

Oligocene reached the stage of oceanic opening in the Burdigalian (ca. 20 – 16 Ma). Figure 3(ca. 20 – 16 Ma). Figure 3 showsshows that this seafloor spreading episode occurred in the European lithosphere (Sardinia-Provence basin) and the western part of submerged orogen (north Algeria basin). The Sardinia-Provence and north Algeria basins are found respectively east and west of the Catalan-Tunisian

fracture zone (Figs. 1 and 3). As both the two deep basins are not penetrable by deep drilling the timing of their oceanic opening can be studied only in the margins.

Formation of Sardinia-Provence basin and counter-clockwise rotation of the Hercynian magma-rich margin of Corsica-Sardinia have been determined from paleomagnetic and geochronological data about the widespread volcanism of western Sardinia12, 13. A temporal overlap of the Sardinian-Provence and north Algeria openings has been considered by various authors5, 10. A 17.8 Ma dating of monazite (deformed leucogranite of Edough granitoid Massif of Little Kabylia; site 12,) may reflect the age of thrusting connected with opening of the north Algeria basin14. Emplacement of granitoids, and andesite and dacite bodies along the Algerian coast (16-15 Ma) may go with the end of oceanic spreading of the corresponding offshore15.

Figure 4. Multibeam seafloor morphology of the Vavilov bathyal plain from bathymetric survey16; illumination from the NW. Main morphological elements are: the large volcanoes Vavilov (V) and Magnaghi (M), the Gortani (G) and D’Ancona (Da) ridges, the De Marchi (De) and Flavio Gioia (F) tilted blocks and the Selli Line (SL) fault. Refer to text for discussion of salient features of the DSDP and ODP drillsites; the site of ODP 654 drilling is placed 65 km (35 nm) to the WNW of site 653.

Late Miocene (ca. 7.5 – 6.3 Ma)Late Miocene (ca. 7.5 – 6.3 Ma)A recent morpho-bathymetric multibeam survey16 (Fig. 3) and available information of

basement lithology17 provide important evidence for the better understanding of the complex Tyrrhenian opening. The morpho-structural features of the Vavilov bathyal plain (VB; 3400-3600 m bsl; Fig. 5) are multifaceted. In its northern part, two seamounts represent inherited stretched relics of OAA. The western De Marchi (De) and the Flavio Gioia (F) seamount to the east show N-S trend and elevation of 1200 m above the plain. The NE-SW Selli line (SL) is an important morphological feature separating the Tyrrhenian bathyal area from the passive margin offshore Sardinia. The former area is located within the stretched OAA and the latter belongs to the Hercynian lithosphere of the rotated Corsica-Sardinia block. The SL is the sea-floor expression of low-angle, east-dipping detachment faulting of continental crust which soles in the upper mantle beneath the Vavilov basin6. The N-S oriented, 40 km long Gortani ridge (G) with elevation of ca. 300/400 m is positioned between the De Marchi and Flavio Gioia. In G, beneath 80 m thick sediments of late Pliocene – Quaternary age, the ODP site 655 drilled basalts of

MORB (Mid Ocean Ridge Basalt) type. To the east of (G) and north of Vavilov seamount (V), ODP site 651 is floored with mantle peridotite. In the sourthern part of the Vavilov plain between the big volcanoes Magnaghi (M) and (V), the arcuate D’Ancona (Da) ridge initiates between the SL and De Marchi with elevation of 200-400 m and sediment cover up to 250 m. This bathyal structure reflects the complex architecture of oceanic opening within the stretched relics of OAA. Seismic reflection and magnetic anomaly data indicates that isolated, deep-seated blocks of probable continental crust occur in the up to 800 m high part of the D’Ancona ridge flanking Vavilov seamount.

In the eastern rim of Vavilov bathyal plain, at waterdepth of 3507 m the DSDP site 373 drilled 190 meter of lava flow and breccia of MORB-like composition below 280 m of early Pliocene-Quaternary sediments (Fig. 4). Six whole rock K/Ar determinations point to 7.5 to 6.3 +/- 0.8 Ma (late Tortonian – early Messinian) for the site 373 basalt sequence 18, 19. The Tyrrhenian sea evaporitic sediments are linked to the global event called the “Messinian” salinity crisis which initiated 5.96 Ma ago20, after the start of the Messinian at ca. 7.25 Ma, and ended at 5.33 Ma21 (start of the Pliocene). Thus, the Vavilov opening is older than the evaporitic event. The absence of evaporites in the bathyal plain ought to reflect a shallow waterdepth which impeded inflow of Atlantic water in sufficient amount to form such deposits at the time of the salinity crisis.

In the southern part of the Vavilov plain (below the 40° parallel; Fig. 4), the W-E trending lithosphere stretching was probably stronger than in the northern part. In fact, in the plain eastern margin, along the 13°E longitude the presence of oceanic crust at site DSDP 373 (MORB-like basalt) and continental crust in the Flavio Gioia seamount suggests diverse intensity of lithosphere stretching. The interactions among faulting and magmatism showed clearly diverse characteristics in the south and north part of the Tyrrhenian basin. The strong extensional deformation of the south Tyrrhenian (e.g. simple shear Wernicke model) was a result of east-dipping low-angle detachment faulting 6, 17. Hyperextension affected both the OAA, where Vavilov oceanic lithosphere is emplaced, and the adjacent submerged continental margin of Hercynian Sardinia. In the Vavilov plain are found mantle peridotites (ODP site 651) and MORB-type basalts (DSDP site 373; eastern rim). In the Sardinia margin volcanism is absent. North of the 41° parallel lineation zone, 8 - 6 Ma old granitoid plutonism extends from the submerged Vercelli seamount and Etruschi ridge to the islands of Montecristo and Elba11 (Figs. 5, 6). High-angle faulting accompanied moderate extension of this continental lithosphere22. Strong igneous activity and moderate extensional tectonics (e.g. pure shear Wernicke model) contrast with the hyperextension and weak volcanism of the south Tyrrhenian “mature “ rift. Overall, low-angle detachment faulting linked to mantle peridotite exposure and non-axial magma-poor volcanism of the Vavilov plain, in the late Miocene, ought to provide useful constraints for the oceanic opening of the large continental margins23. Moving from north to south, the emplacement of granitoids and MORB-type basalts probably reflects increasing strength of lithosphere extension (Fig.6). The stretching of Tyrrhenian upper plate lithosphere seems to mirror the diverse nature of the lower plate which subducted beneath the Apennines: the less subductable continental lithosphere of Adria passes to the cold, more subductable oceanic lithosphere of the Ionian seafloor22.

Late Pliocene (ca. 1.87 – 1.67 Ma)Late Pliocene (ca. 1.87 – 1.67 Ma)Between 1.87 and 1.67 Ma about the Olduvai chron, MORB-type basalts were emplaced

in the western rim of Marsili plain (ODP site 650)17. The Tyrrhenian oceanic opening has been discontinuous. The intensity of extension and volcanism varied in the course of time. The late Tortonian-early Messinian and late Pliocene episodes of the Vavilov and Marsili plains have been characterized by hyperextension and low-standing localized volcanism linked to round-shape magnetic anomaly. The Pliocene and Quaternary episodes (see Supplementary Info S2), on the contrary, show minor extension and strong high-standing volcanism, and elongated magnetic patterns. Overall, oceanic opening has been characterized by accretion of alternating horizontal and vertical type accompanied by eruption of deep-seated and high-standing volcanics, respectively.

Peri-basinal magmas coeval with oceanic opening between 20 and 16 Ma

European plateEuropean plateVolcanics showing composition from basalt and andesite to ryolite, and K/Ar datings

between ca. 19.8 and 15.8 Ma occur in the graben of western Sardinia, in southern Corsica and Mallorca island. Literature geochemistry and age data of these rocks are listed in Supplementary Table S4.Mediterranean orogen of Alpine age Mediterranean orogen of Alpine age

Dikes crop out in Malaga-Marbella (site 14, Betic region) in the form of W-E trending westwards translated bodies24. The rootless dike swarm composition, tholeiitic and transitional to calc-alkaline, ranges from low-K basaltic andesite to medium-K andesite (samples AM24 to FG22; Supplementary Dataset S4). The Malaga basaltic dikes yielded 40Ar/39Ar ages of 17.4, 17.7, 19.8, 17.4, 30.2 and 33.6 Ma 24, 25. Granite dike from the Malaga area (site 14; sample MI22), granite clast from ODP Hole 977 (site 15, sample 7646), diorite clast from Carboneras (site 10) and dacite from Mar Menor (site 17; sample MM2703) yielded 40Ar/39Ar ages of 18.5, 17.6, 18.9 and 18.5 Ma, respectively24, 25, 26. Intrusive rocks from the Sierra Cabrera (site 16) yielded Rb/Sr dates of 20.4 and 18.8 Ma27. The K/Ar and Ar/Ar age spectrum between 19.8 and 17.4 Ma of Alboran-Betic magmatics appears to be analytically consistent since it has been obtained from samples of highly diverse potassium content such as tholeiite groundmass and K-feldspar separates of granite and dacite. More radiometric age determinations could clarify if tholeiitic volcanism older than 19 Ma occurred in the Malaga area.

Figure 2/B shows that intrusives are widespread in the Algerian margin. Granodiorites are exposed in Thenia (site 10a; sample T22), monzonites and diorites in Bejaia-Amizour (site n. 11; samples A12, A1, A9). Cordierite-granites (samples U3, L61), gabbros and rhyolites (sample C1) crop out in the vulcano-plutonic complex of Cap Bougaroun-Collo (20 x 10 km; site 12), rhyolites in El Milia (about 30 km to the south of site 12); and tholeiitic basalts in Dellys (site 19). The space-time distribution of volcanics and magmatics that are not coeval with the oceanic openings is issue of Supplementary Info S2.

Figure 5. Histogram of age data (number of ages vs age data) of magmatics from the Provence-Corsica-Sardinia-Tyrrhenian-Peninsular Italy area since the Oligocene. a) = the age clusters of the Oligocene -mid Miocene (ca. 33/32 - 12 Ma), Pliocene (ca. 5.4 - 1.8 Ma) and Quaternary (ca. 1.2 - 0 Ma; see Fig. 6 and text); b) = the episodes of oceanic spreading (OS) which formed the basins of Sardinia-Provence, Vavilov and Marsili. With respect to the

peripheral areas of the basins, volcanic activity has been abundant during OS1, and absent or scarce during OS2 and OS3. Legend: th = tholeiites; grd = granitoids.

Relationships between oceanic opening and peri-basinal magmas

Age distributionAge distributionAn age histogram illustrates the distribution of geochronology data of mag-matics from the Provence-Corsica-Sardinia-Tyrrhenian region and the penin-sular Italy since the Oligocene (Fig. 5/a). Figure part (b) shows that intra-basin magmatics were present during the Tyrrhenian spreading episodes of the late Miocene (Vavilov basin, OS2) and the late Pliocene (Marsili basin, OS3). In the Burdigalian, seafloor spreading of the Sardinia-Provence basin (OS1) occurred in concomitance with strong eruptive activity of the margins. By the same period, also the opening of the north Algeria basin of the west Mediterranean OAA was accompanied by intense eruptive activity of the margins (Fig. 2). The late Miocene and late Pliocene episodes of oceanic opening of the bathyal plains of Vavilov and Marsili occurred, on the contrary, when volcanism has been absent or scarce in the Tyrrhenian Sea margins.

The Oligocene magmatics show up to ca. 400 km transversely to the SW-NE trend of the submerged OAA and European margin, and along the CTFZ (see the distance between the sites n. 2/4 and 11/13 of Fig. 2/A) on one hand. On the other hand, the SE-NW trending volcanics of the rotated Tyrrhenian margin (< 1 Ma) are no more than 100-200 km wide in across-arc direction (Fig. 6). In the Burdigalian, basalts of tholeiitic type (Figs. 2, 5) erupted during peak volcanism. On the other hand, seafloor arc tholeiites (ca. 1 Ma) pre-date the acme of the Aeolian island volcanism (ca. 0.2 Ma).

Figure 6. Distribution scheme showing the “in situ” magmatics of the Tyrrhenian region and surroundings. Legend: 1 = calc-alkaline volcanics erupted between ca. 33/32 and 12 Ma; 2 = oceanic spreading of Vavilov bathyal plain (ca. 7.5 - 6.3 Ma; DSDP site 373, see *); 3 = post-orogenic granitoids of the north Tyrrhenian (ca. 8 to 6 Ma, late Miocene); 4 = magmatics erupted between ca. 5 and 2 Ma (Pliocene); 5 = oceanic spreading of Marsili bathyal plain (ca. 1.87 - 1.67 Ma; ODP site 650, see *); 6 = <1.2 Ma volcanics (Quaternary). an = magmatics exhibiting alkaline (intraplate, OIB) character, and Pliocene to Quaternary age. In Capraia island, Nefza area and Iblei mounts are present also volcanics of late Miocene age. Abbreviations: A = Algeria, Ace = seamount Aceste, Anc= seamount Anchise, Ca = Capraia island, Co = Corsica, E = Elba island, G = Gortani ridge (ODP site 655), Gi = Giglio island, M-O = Montecatini V/C - Orciatico, Mag = seamount Magnaghi, MB = Marsili basin, Ne = Nefza area, P = ocean-floor peridotite (ODP site 651), Po = Ponza and Palmarola islands, Pr = Provence, S = Sardinia, Si = Sisco; T = Tunisia, To = Tolfa, V = Vercelli seamount, VB = Vavilov basin, Ves = Vesuvius - Campi Flegrei, Vul = M. Vul -ture. Dotted line shows the position of lithosphere-asthenosphere section of Fig. 7/B.

Figure 7. Schematic lithosphere-scale cross sections: A), from Provence (France) to the Ionian area (location in Fig. 3/B); the oceanic spreading of Burdigalian age (between ca. 20 and 16 Ma) produced the Sardinia-Provencal basin (Sa-Pr; European plate); B), from Sardinia to the Vavilov - Marsili oceanic basins and the Ionian (location in Fig. 6). AM = asthenospheric mantle, LM = lithospheric mantle, MORB = Mid-Ocean-Ridge-Basalt magma source in AM, ANOR = Anorogenic (intraplate, ocean-island-basalt) magma source in AM. It has here been assumed that the past lithosphere thickness of the Alpine-Betic orogen was comparable to that of nowadays Alps. Emplacement of the calc-alkaline magmas before start of WNW-directed subduction implies that the metasomatic modification of the corresponding igneous sources has been produced by lithosphere shortening of Hercynian or Alpine age. Because the orogenic accretion processes are repeated in time, Hercynian remnants are likely present in the metasomatized bodies of Alpine-age, and Alpine remnants in the bodies of Apennine-age.

Start of WNW-directed subductionStart of WNW-directed subduction The above mentioned space-time aspects indicate that the Burdigalian opening on one

side, and those of the late Miocene and late Pliocene on the other, are probably linked to clearly distinct tectonic environment. This reconstruction considers that the WNW subduction was commenced at ca. 16/15 Ma (Burdigalian-Langhian transition; Fig. 2/B), after the clearly distinct episodes of post-orogenic rifting (Oligocene-Aquitanian) and seafloor spreading (Burdigalian). The waning of allochthonous volcanoclastic deposits of the Apennines occurred possibly at the nascence of WNW subduction of lithosphere belonging to the African plate under the retro-verging portion of the Tyrrhenian OAA (see Supplementary Info S3). The embryonic slab went with eruption of volcanics of less common type (comendites of SW Sardinia, European plate,

and lamproites of NE Corsica, the Tyrrhenian part of the OAA; Supplementary Dataset S4). The slab origin may be useful for recognizing the early formation of the Maghrebid-Apennine thrust belt.

DiscussionOverall, rift tectonism is either of “failed” (incomplete) or “mature” type: the former is

linked to continental lithosphere thinning typically characterized by horst-graben structure, the latter reaches the stage of oceanic basin opening. In the west Mediterranean and surroundings Tertiary-Quaternary rifting of “failed” type produced thinning and stretching of various regions such as Valencia basin, Alboran Sea, Sicily Channel, Aegean Sea, Rheintal, Rhone Valley, Limagne-Massif-Central-Bresse. “Mature” rift can be distinguished from aborted rift spatially or temporally. A spatial distinction is found in the Tyrrhenian as late Miocene rift activity of “failed” and “mature” type occurs respectively to the north and the south of the 41° parallel lineation zone. In fact, modest extension (incomplete rift) accompanied the magmatism of granitoid nature of the north Tyrrhenian seafloor (Fig. 6). On the other hand, strong extensional deformation went with the Vavilov plain volcanism of MORB type (mature rift) to the south of the lineation. Granitoid magmas are widespread in the north Tyrrhenian, whereas basalt volcanism appears limited to the eastern rim of Vavilov plain (DSDP 373A; Fig. 4). Spatial distinction is also manifest in the Mediterranean OAA during the Burdigalian. In fact, rifting of “failed” and “mature” type in the absence of subduction occur respectively to the east (future Tyrrhenian sea) and west (north Algerian basin) of the Catalan-Tunisian fracture zone. More in the past, the Permo-Triassic “failed” rift of the southern Alps could have been associated with the distant opening of the Permo-Triassic Tethys. Regarding the temporal distinction, rift/spreading transition of the Mediterranean OAA occurred in Burdigalian, late-Miocene and late Pliocene time. Pre-Oligocene (> 33/32 Ma) lithosphere thickening above SE-subduction of European lithosphere produced the Mediterranean-Tyrrhenian OAA. Structurally, the orogen was made of fore- and retro-belt. WNW-directed subduction of African plate beneath the retro-belt commenced, most likely, at the Burdigalian-Langhian transition (ca. 16/15 Ma) was favoured by vergence similarity with the nascent Maghrebid-Apennines. The Oligo-Burdigalian stage of rifting in concert with volcanism of the Tyrrhenian OAA was possibly akin to the post-Laramide rifting and volcanism of the Basin and Range. Overall, intramontain lithosphere rupture and volcanism of calc-alkaline nature produce fault-bounded horst, exposing crystalline-metamorphic and volcanic rocks, and alternating with grabens that contain thick deposits of volcanoclastic and siliciclastic nature. Calc-alkaline volcanoclastic deposits of Oligocene – Burdigalian age are found as allochthonous bodies in the Apennines in the absence of the emission centres (see the Supplementary Info S3, and Dataset S5, S6). At the nascence of WNW subduction and Apennine thrusting, the upper plate source area of the allochthonous volcanoclastics was probably affected by inversion tectonics in which a compressional stage follows the extension-dominated stage. The fate of the volcanoclastics could have been determined by the significant change of tectonic mode of their sites of origin in the former Tyrrhenian OAA. By the start of WNW subduction, inversion tectonics could initiate the down-faulting of the original horst volcanoes (past topographic highs) and the thrusting of the fault-bounded grabens bearing volcanoclastic deposits (former lows). In the more orthodox concept of West-Mediterranean-Tyrrhenian evolution, the persistent WNW subduction of the last 33/32 Ma excludes horst-graben inversion. Also the thick siliciclastic graben successions of the Apennines and the nonappearance of the past structural highs could be a consequence of inversion tectonics. The connection of volcanism of calc-alkaline type far from subduction zone most probably implies that igneous sources have been metasomatized by crustal material brought downwards during clearly past lithosphere shortening and plate convergence. Overall, the geological literature indicates that the temporal gap intervening between tectonic mode linked to metasomatic modification and igneous activity of calc-alkaline type can be highly variable.

The study area may have had important geological connections with the Alps. The compression tectonics of the Alps has been interrupted and supplanted by extension during the Oligocene - early Miocene. The high geothermal gradient due to extension and necking caused generation and uprise of calc-alkaline melts28, 29. By the end of early Miocene, igneous activity and extension ceased and the orogenic accretion of the Alps resumed. The resumption of

lithosphere shortening in the Alps appears to be penecontemporaneous with the start of oceanic opening of the West Mediterranean.

In conclusion, after the pre-Oligocene Alpine accretion linked to SE polarity two most probable episodes of tectonic and magmatic activity are recognized. The Oligocene-Burdigalian episode (ca. 33/32 - 16 Ma) saw rift activity in the absence of subduction. Calc-alkaline acidic magmatism of the Oligocene-Aquitanian (ca. 33/32 - 20 Ma) was followed by volcanism of bimodal, basic – acidic nature linked to oceanic basin formation of the Burdigalian (ca. 20 - 16 Ma). In the Langhian to Recent (ca. 16/15 - 0 Ma) episode, the tectonic and magmatic activity was linked to subduction showing WNW-direction. Following the view of this work, the tectonic setting of the Apennine Macigno Formation showing pre-Langhian age (> 16/15 Ma) was of graben-type whereas the post-Burdigalian (< 16/15 Ma) Marnoso-Arenacea had setting of foredeep-type. The supra-subduction formation of the Tyrrhenian bathyal plains of Vavilov and Marsili is a four stage process. The short-lived late Miocene and late Pliocene stages are characterized by strong spreading. Hyperextension deformation was accompanied by horizontal accretion of the low-seated oceanic crust. The Pliocene (5.33 – 1.87 Ma) and Quaternary (1 Ma to Recent) episodes were affected by weak spreading (Supplementary Info S2). Weak, localized extension was accompanied by vertical accretion which produced high-standing basaltic seamounts. MORB-type lavas (ODP655) created the modest elevation of 4.3 Ma old30 Gortani ridge, NW of DSDP373 (Fig. 4). Afterwards, MORB volcanism migrated ESE, towards the hinge zone. In the course of migration, from Gortani ridge to the axial volcanoes of Vavilov (< 2.4 Ma) and Marsili (< 0.8 Ma), crest elevation increased. Eventually, large magma input formed the over-fed Marsili volcano, the last of the “sui generis” spreading axes of the Tyrrhenian. Weak horizontal deformation is linked to ascent and emplacement of < 0.5 Ma old basalt melts of alkaline type in the crest of Vavilov volcano11.

As the Tyrrhenian part of OAA was affected by the late Miocene strong oceanic spreading, hyperextension occurred also in the adjacent Hercynian margin of Sardinia. By contrast, the north Algerian oceanic opening and that of Sardinia-Provence were entirely located respectively in the OAA and the Hercynian European lithosphere. In this view, it appears that the tectonic mode linked to the Tyrrhenian continent-ocean transition could be diverse from that of the Burdigalian opening. The space-time analysis indicates that calc-alkaline volcanism and extension occur also in the absence of subduction.

Acknowledgements. F. Guerrera generously contributed to the review of the salient characteristics of the allochthonous volcanic sedimentary rocks of the Apennine-Maghrebid thrusts. I thank one anonymous reviewer and E. Bonatti for insightful suggestions which allowed to improve the quality of the article. There has been helpful exchange of ideas with H. Bellon, C. Doglioni, E. Gueguen, K. Kastens, M. Ligi, M. Lustrino, A. Malinverno, M. Mattioli, N. d’Oraye, J.G. Sclater and N. Zitellini. The report of the Pieve Santo Stefano buried volcanic body was obtained by courtesy of ENI/AGIP, Exploration division. The article is dedicated to the memory of Mario Fornaseri, Michele Deriu, Renato Funiciello, Fabrizio Innocenti, Raimondo Selli. It would never have been possible without Maria Pia.

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SUPPLEMENTARY MATERIAL

The supplementary numerical Tables S4, and S6 are obtainable via request to the author.

Supplementary - S1: Brief description of previous tectonic reconstructionsIt is generally considered that calc-alkaline volcanism, oceanic spreading and bending of

the Maghrebid-Apennines belt were linked to roll-back of WNW-directed subduction of African plate from early Oligocene to Recent. For the most part, the authors call for the arc environment on the assumption that calc-alkaline magmas and oceanic opening probably require concomitant slab retreat extending from the north Apennines to western Maghreb (see, e.g., Malinverno and Ryan, 1986; Lonergan and White, 1997; Carminati et al., 1998a; Wilson and Bianchini, 1999; Argnani and. Savelli, 1999; Maury et al., 2000; Cibin et al., 2001; Barruol and Granet, 2002; Rosenbaum et al., 2002; Spakman and Wortel, 2004; Martin, 2006; Scrocca et al., 2005; Heymes et al., 2008; Vignaroli et. al., 2008). In the subduction-controlled environment has been considered the occurrence of: slab break-off (Carminati et al., 1998a, b; Benito et al., 1999; Hoernle et al., 1999; Maury et al., 2000; Cavazza et al., 2004), slab tear (Patacca et al., 1990; Marani and Trua, 2002; Faccenna et al., 2004, 2007; Chiarabba et al., 2008; Rosenbaum et al., 2008), inversion of subduction polarity (see, e.g., Boccaletti et al., 1971; Rehault et al., 1984; Doglioni et al., 1998, 2004; Gueguen et al., 1998; Peccerillo, 1999; Savelli, 2002, 2011), slab roll-back without polarity inversion (Beccaluva et al., 1994; Argnani et al.,1995; Lonergan and White, 1997), and delamination of subducted lithosphere (Serri et al., 1993; Hoernle et al., 1999). Among the extension-controlled processes, various authors consider convective thinning of lithospheric mantle and orogenic collapse (see, e.g., Doglioni, 1995; Turner et al., 1999; Doblas et al., 2007). Doglioni (1992) and Keller et al. (1994) propose that the eastward mantle flow is at the origin of back-arc extension and consecutive oceanic opening. Doglioni et alii (1999a, b) suggest that mantle flow results in the contrasting modes of the steep and flat subduction zones. The “two subductions” concept considers that flat E-subduction zones are associated to uplifting mountains (e.g., the western Alps) and steep W-subduction zones to small elevation of the chain (the Apennines).

Lavecchia and Stoppa (1990, 1996) and Bell et alii (2006) believe that east-dipping detachment faults of the Sardinia/Tyrrhenian region and volcanic activity associated with eruption of carbonatite rocks and deep-seated CO2 emission of the Apennine region took place in response to the ascent of intra-continental plume. Diverse, but not mutually exclusive processes, occurred in the western passive and the eastern active margin (Kastens et al., 1988; Keller et al., 1994; Sartori et al., 2004). While the passive continental Corsica-Sardinian margin is thinned and stretched by detachment faults, back-arc extension and arc volcanism migrate eastwards. This reconstruction might recall the idea of Tatsumi et alii (1990) that asthenosphere injection into the mantle wedge forced slab steepening and back-arc extension. Some authors (Turner et al., 1999; Doblas et al., 2007) consider that the post-collision Betic-Alboran magmatism was a consequence of convective removal of lithospheric mantle and lower crust in the absence of subduction. Local comenditic rocks from Sardinia and lamproitic rocks from Alpine Corsica are thought to reflect a tectonic environment of continental extension rather than subduction (Morra et al., 1994; Prelevic et al., 2007). Mantovani et alii (2002) and Viti et alii (2009) consider that Africa-Europe plate motions drove wedge extrusion and formation of the trench-arc-back-arc sequence. The slab beneath the Gibraltar arc is regarded as the counterpart of the Calabrian arc at the eastern termination of the WNW subduction beneath the Maghrebid-Apennines belt (Lonergan and White, 1997; Gutscher et al., 2002; Faccenna et al., 2004; Doblas et al., 2007). In this view, the former arc migrated to the west and the latter to the east. It has been proposed that the Sardinia calc-alkaline magmas originate from igneous sources which were metasomatized during plate convergence of Hercynian age (Rehault et al., 1984; Savelli, 2002, 2005). Figure 2 shows that the pre-Oligocene (> 33.9 Ma; International Stratigraphic Chart, 2009) NW-verging front of shortening due to collision of the European and African plates was accompanied by formation of SE-verging back-thrusts which will be the hinge zone of future WNW subduction of African lithosphere beneath the Maghrebid-Apennines belt. The similar SE-vergence of the inherited back-thrusts of Mediterranean OAA and the thrusts of the Apennines (Keller et al., 1994; Doglioni, 1998; Gueguen et al., 1998; Scrocca et al., 2005) causes difficulties in determining initiation of the WNW subduction. Some authors (Carminati et al., 1998b; Cibin et al., 2001; Faccenna et al., 2004; Rosenbaum et al., 2008; Conticelli et al., 2009) propose that subduction started in early Oligocene (ca. 34/30 Ma), and some others (Gueguen et al., 1997, 1998; Guerrera et al., 1993, 2004, 2005) in late Oligocene (ca. 25 - 23 Ma or late Oligocene-

Aquitanian time, ca. 25 – 20 Ma). Subduction beneath the northern part of the Tyrrhenian/Apennine system initiated probably not earlier than ca. 20 – 14 Ma (early-middle Miocene; Savelli 2000; Guerrera et al., 2012). Maury et alii (2000) propose 16 Ma for slab break-off and commencement of calc-alkaline magmatism along the Maghreb margin. Given spreading rate of ca. 5 cm/a and slab depth of ca. 500 km beneath the Tyrrhenian basin, Francalanci and Manetti (1994) consider subduction duration of 10 Ma.

Supplementary - S2: Periods of weak extension and volcanism not coeval with the oceanic openingsOligocene - Aquitanian (ca. 33/32 - 20 Ma)Oligocene - Aquitanian (ca. 33/32 - 20 Ma)

European PlateEast of the Catalan-Tunisian fracture zone, the island of Sardinia saw intense rift activity. In the

west Sardinia graben (Fig. 3/A, main text), lava flows and domes - often intruded by dikes and autobrecciated - are accompanied by ignimbrites, pyroclastics and pillow basalts. A series of individual volcanic complexes is the typical product of Sardinia volcanism. Rock composition varies from basalt to andesite dacite rhyolite, the serial type from tholeiitic and medium-K calc-alkaline to high-K calc-alkaline/shoshonitic, and the age from ca. 29 to 12 Ma (Deriu, 1962; Coulon et al., 1974; Coulon and Dupuy, 1975; Savelli et al., 1979; Dostal et al., 1982; Beccaluva et al., 1994; Argnani et al., 1995; Conte, 1997; Lustrino et al., 2004; Gattacceca et al., 2007). Andesitic lavas and ignimbritic rhyolites are the prevailing lithotype of the island (Tab. 1). The Sarroch volcanic complex (site 5; Fig.3/A) is made of basalts, basaltic andesites and andesites (samples SH-32, SH-55, SH-48 of Tab.1; Conte, 1997). Basalts and andesites crop out in Cixerri (site n. 6; Savelli et al., 1979); microdiorites, rhyolitic ignombrites, dacites and andesites in Alghero-Oniferi (site 7; Bellon, 1981, Gattacceca et al., 2007); basalts, basaltic andesites and andesites in Bosano-Logudoro-Capo Marargiu (site 8). In Provence are present andesites, dacites and subvolcanic microdiorites (sites 3, 4). Andesite and dacite are lava flows (samples 77S4F, Est96-2, PR4), gabbro xenolith is present in dacite lava (sample PR7a from Esterel area), and andesite clasts (in the Villeneuve-Loubet conglomerate near Nice (sample PR2) (see note at foot of a previous page).

In Valencia basin, to the west of Catalan-Tunisian fracture zone offshore exploration wells sampled early Miocene sediments bearing pyroclastics of andesitic to rhyolitic composition (site 1; Marti’ et al., 1992). The DSDP hole 123 drilled pyroclastics (site 2; samples n. 2/6a and 2/6b) of dacitic and rhyolitic composition which yielded K/Ar dates of 24.4, 21.9 and 20.8 Ma (Ryan et al., 1972).

Mediterranean Orogen of Alpine age West of the Catalan-Tunisian fracture zone, ca. 24.8 to 20.8 Ma old leuco-granite clasts are

present in the Betic area (site 10; Bellon et al., 1983). Rhyolitic pyroclastics (22-21 Ma, site 9) and volcanogenic turbidites show Aquitanian-Burdigalian age (Algeciras, site 2 - in italics, Fig. 3). In the Algerian Maghreb, the granodiorite from Bejaja-Amizour (Great Kabylia) and the granitoid from Beni Toufout (Little Kabylia) show late Oligocene (24.4 Ma; site 11) and Aquitanian age (22 Ma; site 12), respectively (Bellon, 1981). These intrusions are slightly younger than the peak thermo-metamorphism of the Kabylia crystalline basement which is dated at ca. 25 Ma (Monie’ et al., 1995).Langhian - Tortonian (ca. 16 - 7.5 Ma)Langhian - Tortonian (ca. 16 - 7.5 Ma)

European PlateIgnimbritic rhyodacites and andesites (sites 42, 43), comendites (site 44), and andesites (near to

s. 6) crop out in northern, southwestern and southern Sardinia respectively. Shoshonites are found in the Sardinian offshore (site 45; sample Sar1.03; Mascle et al., 2001) and andesites in the Ligurian offshore (Rollet et al., 2002; p. -17).

Mediterranean Orogen of Alpine ageAlboran region West of the Catalan-Tunisian fracture zone, magmas erupted mostly along

lineation zones trending SW-NE (Hernandez et al., 1987; Duggen et al., 2004), W-E (Torres Roldan et al., 1986) and WSW-ENE (Hoernle et al., 1999). The SW-NE lineation (Trans-Alboran fracture zone) extends from the Trois Fourches promontory of Morocco to the Betic area of Cabo de Gata (sites 30, 26, 27). Along such lineation ODP Hole 977 (site 15) recovered gravel pebbles which have dacite, basalt (sample 7523) and rhyolite composition (sample 7521) and ages between 12.1 and 9.3 Ma (Hoernle et al., 1999; Duggen et al., 2004). Pebbles from Hole 978 (near to s. 15) exhibit composition from basalt to rhyolite and serial type ranging from tholeiite to shoshonite (Hoernle et al., 1999). The pebbles below early Pliocene sediment of ODP Holes 977 and 978 probably derived from the widespread late Miocene erosion process. At the Yusuf ridge is present andesite (10.7 Ma; sample CYA 5-6) and at Mansour seamount basaltic andesite (8.7 Ma: sample POS III-D-1; Duggen et al., 2004). Sea-floor rhyolites (9.4-9.3 Ma; site 26; sample CYA3-11) accompanied by subaerial tholeiitic lavas and andesitic pyroclastics are present along the lineation trending WSW-ENE of the submerged ridge near to the Alboran island (Duggen et al., 2004; Gill et al., 2004).

Betic region. Volcanic activity was intense in the Betic region between ca. 12 and 9 Ma. The 8.9, 8.8 Ma old basalt and latite of Mazarron (site 28) show high-K calc-alkaline and shoshonitic type, respectively (samples B302 and MAZ8; Benito et al., 1999; Turner et al., 1999). Granodiorites, diorites, rhyolites, dacites, andesites, basaltic andesites and basalts erupted in the time span from ca. 15 to 8-7 Ma in the Cabo de Gata region (site 27; Bellon et al., 1983; Di Battistini et al., 1987; Hernandez et al., 1987; Turner et al., 1999). The ca. 1000 m thick CA lavas of Cabo de Gata exhibit K/Ar age between 15.2 and 7.9 Ma (Bellon et al., 1983). Di Battistini et alii (1987) report that 12.1 to 9.2 Ma old amphibole-bearing andesites dacites and rhyolites overlie pyroxene-bearing andesites (8.7 to 7.5 Ma; samples CG200 599-9, Sp317, Sp333, Sp253).

Morocco Rif. Pyroclastics and block lavas of basaltic-andesitic and andesitic, medium-K calc-alkaline composition from Ras Tarf (site 29; sample 116-72) yielded K/Ar dates of 15, 13.1, 12.1 Ma (Bellon, 1981; El Azzouzi et al., 1999; Maury et al., 2000). More to the east at the southern end of Transalboran shear zone, rhyolites crop out in the Trois Fourches promontory (9.8 Ma; site 30; sample G44; El Bakkali et al., 1998). Rocks of high-K calc-alkaline, granodioritic and andesitic composition (samples G8, G1, G15) from the adjacent volcano/plutonic complex of Gourougou show ages of 8.1, 7.9, 7.7 Ma respectively (El Bakkali et al., 1998; El Azouzi et al., 1999). In addition, the Gourougou area is characterized by eruption of shoshonitic rocks showing composition from basalt to trachyte (samples G47, G74) and K/Ar age older than the Tortonian (between ca. 7.0 and 5.4 Ma).

Algerian Maghreb. In the Great Kabilya region of Algeria (site 20) the pre-Langhian magmatics were followed by emplacement of latite dikes with age of 12.4 Ma. Louni Hacini et al. (1995) report K/Ar age of 15 Ma for the rhyolitic dome of Sahel of Oran (site 31) which was followed by high-K calc-alkaline andesites and dacites with K/Ar ages between 11.7 and 7.2 Ma (dike sample OR10), and 7.5 Ma old latites (site 32; latite dome of M’ Sirda; sample ORbd1). Rhyolitic dikes cutting the Thenia granodiorite of Burdigalian age (site 10a; sample T 36) have been dated 14-12 Ma. Bellon (1981) indicates 16-15 Ma for the rhyolites and rhyodacites from Menacer area (site 36), Maury et alii (2000) 13-11 Ma for K-rich granites from the Cherchel area (site 34) and Belanteur et alii. (1995) 11.8 Ma for basaltic andesite from the area of Dellys (near to site 19; sample DLBO). According to Bellon (1981) andesites and shoshonites of the Cherchel area (site 35) gave K/Ar ages of 13.1/12.4 and 9.0 Ma (respectively), and andesites of Kef Hahouner (site 39) 10.9/9.3 Ma. Ca. 15.3 Ma cordierite-bearing granitoids of Djebel Filfill (Little Kabylia; site n. 37; sample II-6) are of K-rich type. Granite and diorite crop out in Annaba (K/Ar age of 15.9 and 15.8 Ma; site 38, near to the western margin of Little Kabylia; Bellon, 1981); gabbros in Cap de Fer-Annaba (sample VPE-271) and basalts in Cap Djinet (13.7 and 12.2 Ma; site 36; samples Dj2, Dj1; Fourcade et al., 2001).

Tunisia. The ca. 13 Ma old cordierite-bearing granitoid intrusion of Oued Belif (site 40; Nefza region) was followed by eruption of dacites and rhyodacites between ca. 12.9 - 8.2 Ma; cordierite-bearing, K-rich granitoids and rhyolites crop out in the island of La Galite (ca. 14.2 and 10 Ma; site n. 41; Bellon, 1981; Maury et al., 2000).

NE Corsica. East of the Catalan-Tunisian fracture zone, at Sisco crops out a dike body showing lamproitic composition and K/Ar age of ca. 15.0 Ma (site n. 46; Civetta et al., 1978; Savelli, 2000; Conticelli et al., 2007, 2009). This rock has high contents of compatible (K, Rb, Th, Sr, Ba), incompatible (Mg, Cr, Ni) and light rare earth elements, as well as high Sr (0.71228) and low Nd (0.51215/6) initial isotopic ratios (Tab. 1). Pliocene (ca. 5.4 - 1.8 Ma; Tyrrhenian area)Pliocene (ca. 5.4 - 1.8 Ma; Tyrrhenian area)

Major sources of detailed documentation for the Pliocene and Quaternary magmatic episodes in and around the Tyrrhenian sea (Figs. 6, 7) are found in Selli et alii (1977), Savelli (1984, 2002), Serri et alii (1993), Faggioni et alii (1995), Argnani and Savelli, (1999, 2001), Peccerillo (1999), Sartori et alii (2004). After the calc-alkaline volcanic cycle of Oligocene - Langhian age and ca. 7 Ma of magmatic quiescence, Sardinia was affected by basaltic volcanism showing alkaline nature and age from ca. 5.4 to 1.8 Ma (Beccaluva et al., 1977; Savelli, 2002; Lustrino et al., 2004; and references therein). Pliocene basalt volcanism is widespread in the Tyrrhenian seafloor. Alkaline basalts (3.0-2.7 Ma) occur in Magnaghi seamount, MORB-type lavas in the Gortani ridge (4.1 Ma; ODP site 655) and calc-alkaline basalts (2.6 Ma) above ultramafic rock of ODP site 651A. The age of Vavilov volcano is < 2.4 Ma if its magnetic anomaly belongs to the Matuyama chron. Figure 7 (main text) shows that Pliocene magmatics are present to the west of the Tuscan-Roman-Campanian area of abundant Quaternary volcanism. In the Aceste and Anchise seamounts are found volcanics respectively of alkaline and calc-alkaline type. Quaternary (< 1.2 Ma – Recent; Tyrrhenian areaQuaternary (< 1.2 Ma – Recent; Tyrrhenian area ))

Calc-alkaline basalt volcanism (< 0.8 Ma; Selli et al., 1977; Savelli and Gasparotto, 1994; Faggioni et al., 1995; Marani and Trua, 2002) and high angle faulting produce vertical accretion of the large axial seamount Marsili as fast subsidence affects the seamount itself and the contour bathyal plain. Such Quaternary vertical tectonic mode replaces the low-angle detachment faulting of fast horizontal spreading and basalt eruption at ODP site 650 of the late Pliocene. Cocchi et al. (2009) point out that Marsili basin evolves from pure lateral spreading to a superinflated seamount. In the part of the basin to

the east of ODP site 650, the full spreading rate decreases from 3.1 cm/a since the post Olduvai part of the Matuyama (< 1.67 Ma) to 1.8 cm/a since the Brunhes chron (< 0.8 Ma) and the start of the vertical growth of the 3000 m high seafloor volcano.

In the Marsili basin, if the ca. 2 Ma age of opening for 110 km in WNW-ESE direction is true the full spreading rate was ca. 5.8 cm/a. Nicolosi et al. (2006), indicate spreading rate of 19 cm/a for the short-lived Olduvai chron. As the Marsili spreading should be restricted due to nearness of the continental crust, the large above-mentioned rate can be an overestimation. The MORB-like basalt injection at ODP site 650 represents initial oceanic spreading of localized punctiform nature in ambient shallow-water. Such short-lived magmatic emplacement can accompany strong tectonic extension. To the west of the ODP site 650, strong tectonic spreading could affect - hypothetically - the amagmatic thinned continental lithosphere of the bathymetric saddle which separates the bathyal plain of Vavilov from that of Marsili. In the Marsili basin as in the older Vavilov, lateral oceanic accretion evolves to vertical growth producing basaltic seamounts to the detriment of the opening rate. The landlocked Marsili volcano grew up in a more eastward position with respect to the early localized shallow-water spreading of the site ODP 650, whereas the axial volcanoes of the Vavilov plain develop in a more westward position with respect to the MORB-type basalts of the site DSDP 373A. In the Marsili basin, the transition from pure horizontal magma-poor spreading to strong volcanism and vertical accretion of Marsili seamount can be cause or effect, or both cause and effect, of strong slab instability. This geochronological recostruction of the Tyrrhenian opening might show that the Gortani ridge and the seamounts of Vavilov and Marsili can represent the evolution from pure lateral to vertical oceanic accretion with formation of short “sui generis” spreading axis.

During the last 1 Ma, abundant calc-alkaline volcanism affected the Tyrrhenian margin from the Aeolian islands and Vesuvius to the “Roman Province” and southern Tuscany (Main text Fig. 7). The figure shows also that alkaline-olivine basalts are present in the top of Vavilov seamount showing < 0.5 Ma (Selli et al., 1977; Robin et al., 1987; Faggioni et al., 1995), and in NW Sardinia (between ca. 0.8 and 0.2 Ma; Savelli, 1984, 2002). Alkaline contamination of Quaternary peri-Tyrrhenian calc-alkaline volcanics is described by various authors (see, e.g., Ellam et al., 1989; Serri et al., 1993; Francalanci and Manetti, 1994; Argnani and Savelli, 1999, 2001; Peccerillo, 1999; Gasperini et al. 2002; Cadoux et al., 2005; De Astis et al., 2006; Rosenbaum et al., 2008; Trua et al., 2004, 2010).

Supplementary – S3: Volcanogenic allochthons of the Apennines Volcanoclastic sediments Volcanoclastic sediments

The pervasive presence of allochthonous volcanoclastics in the absence of the corresponding emission bodies has attracted the attention of various authors (Mezzetti et al., 1964; Riviere et al.,1977; Borsetti et al., 1984; Critelli et al., 1990; Guerrera et al., 1993, 1998, 2005; Amorosi et al., 1994, 1995; Campos Venuti et al., 1997; Cibin et al., 1998, 2001; Mattioli et al., 2002). The rocks show age from the Oligocene to Burdigalian (Langhian), and calc-alkaline nature (Table 2). In Table 3 are listed the literature geochemistry data of the samples cited in this chapter and Table 2. The dilemma whether the source area was originally located in the Tyrrhenian OAA, to the east of the Catalan-Tunisian fracture zone, is object of debate. The provenance area and the tectonics causing disappearance of the primary emission bodies (the “lost” volcanoes) preservation of the volcanoclastics are related issues which are going to be considered more below. On the whole, volcanogenic sediments from the Apennines were associated to erosion, reworking and basinal slumping (mass-flow) of pyroclastic material and lava and mineral grains. Volcanoclastic sandstones with abundant glass and mineral fragments, tuffaceous and volcanolithic sandstones reflect sedimentation by turbidity currents and mixing with the terrigenous derive mostly from erosion of crystalline-metamorphic basement. Fine-grained ash layers of pyroclastic fall which are often altered to clay minerals are also present. Some authors proposed the volcanoclastics derive from the coeval volcanism of western Sardinia (Tab. 3). Yet, due to its remote location the island is not a likely site of origin; the turbidite and gravity flow characteristics, coarse grain size (from sand to gravel and pebble) and thickness of volcanogenic sediments indicate a nearness of eruption and deposition sites (Critelli et al., 1990; Campos-Venuti et al., 1997; De Capoa et al., 2002).Early Oligocene.

Early Oligocene volcanoclastic beds are widespread in the northern Apennines (Tateo, 1993; Cibin et al., 1998, 2001; Mattioli et al., 2002). The Ranzano formation (l.s., sites 23, 24, 25; Fig. 3, main text) is made up mainly of sands containing plagioclase grains of andesine-labradorite composition associated with glass shards and grains of amphibole, pyroxene, biotite and opaques which indicate primary composition of dacitic-andesitic type (samples 34D, 94, 128 of Tab. 2; Cibin et al., 1998). The detritus is present in “pure” beds which contain around 70-80 % volcanic material and “mixed” beds where volcanic and non-volcanic grains are present in variable amount. Pebble-sized clasts from the Aveto-Petrignacola formation (sites 23, 24) yielded amphibole Ar/Ar ages of 29.8-29 Ma which match the early Oligocene biostratigraphic evidence (Mattioli et al., 2002). Clast composition varies from basalt and basaltic andesite to andesite, dacite and rhyolite (twelve samples; from MM2 to MM114). The lavas

exhibit serial type from low- to medium- and high-K calc-alkaline, and the rhyolitic ignimbrites shoshonitic type. The volcanic sand beds of Reitano-Tusa and Stilo-Capo d’Orlando turbiditic successions (Calabro-Peloritani arc, sites n. 13, 14) show rhyolitic K-alkaline nature and early Oligocene age (Faugeres et al., 1992; Balogh et al., 2001; Baruffini et al., 2002). Oligocene - early Miocene.

Volcanogenic sands showing rhyolitic-rhyodacitic composition are found in the southern Apennines (sites 15, 16, 17; Critelli et al., 1990; Guerrera et al., 1998, 2005; De Capoa et al., 2002). Volcanic ash layers of the northern Apennines (Contignaco, Mongardino and Calderino; sites n. 25-26) are associated with early Miocene clays (Mezzetti et al., 1964; Cibin et al., 2001). Sometimes, the volcanic ashes were modified and altered to various extent: the alteration degree was studied by Mezzetti et alii (1964). The geochemistry diversity between separated shards and whole rock indicates the alteration of Calderino pyroclastics (sample 4). The alteration produced decrease of silica and alkalies, and CaO increase. Conversely, the Mongardino glass (sample 5) was only slightly altered into clay material. In volcanic arenites of the early Miocene San Mauro/Pollica formation (southern Apennines; Crisci et al., 1988; Critelli and Le Pera, 1990) are present lava clasts of rhyodacitic - rhyolitic composition (sites 19-20; samples S2, S3). The arenites contain fragments of plagioclase, quartz, sanidine and biotite; fresh plagioclase with anorthite content of 15 – 40 % shows embayed rims of allotriomorphic quartz.Late Aquitanian – Burdigalian (Langhian)

Figure 3 shows that volcanogenic deposits of Late Aquitanian – Burdigalian age are scarce in Rif and Betics (Maate et al., 1995; Guerrera et al., 1998) and abundant in the Apennines. Turbidite sediments bearing fragments of rhyodacitic-andesitic rocks crop out in the Betic region (sites 1, 3 – in italics; Guerrera et al. 1998, 2005). Maate et al. (1995) report fragments of basalt and andesite lava in turbidites from western Maghreb (sites 4, 5, 6). The “Bisciaro” formation volcanoclastics of the north Apennine Umbria-Marche region (sites 27, 29) yielded K/Ar ages between ca. 22.3 and 17.1 Ma (Balogh et al., 1993). Rhyolitic-rhyodacitic glass shards and plagioclase phenocrysts are present in the “Bisciaro” type deposits of Montebello and Fossombrone (samples 3, B6/1, B8/7; B6(2), B8(1), 80, 80 mc; Guerrera et al., 1986; Coccioni et al., 1988). Delle Rose et al. (1994a, b) reported the occurrence of rhyolitic glass of shoshonitic type among the volcanoclastic layers of the Vicchio marls (site 29). Vicchio glass shards are accompanied by altered andesite clasts and sand-sized grains of fresh andesine, plagioclase, biotite. Conglomerate beds with pebble-size lava clasts of rhyolitic - rhyodacitic composition (samples A II, C 13A, B 12), and volcanic arenites are present in the Gorgoglione flysch (site 22; Le Pera and Ventura, 1994). The clasts contain phenocrysts of plagioclase (An 5-30), K-feldspar, quartz and biotite. Langhian. Pyroclastics of Langhian biostratigraphic age which bear rhyolitic glass shards and biotite crystals (site 11; samples 7, 14) crop out in central Sicily (Spadea and Carmisciano; 1974).The buried volcano of Pieve S. Stefano The buried volcano of Pieve S. Stefano

In the northern Apennines (site 13a) the oil drilling of Pieve S. Stefano recovered calc-alkaline volcanics (ENI/AGIP report - San Donato Milanese, June 1984; Anelli et al., 1994). The 850 m thick ig-neous sequence ends at drilling depth of ca. 4900 m. The core samples m 3870-1 and -2 consist respect-ively of pyroxene-bearing andesite lava and andesite pyroclastics. The presence of “brown-red”colour surfaces likely suggests not less than ten eruptive events. The volcanic sequence was interrupted by two large anhydrite slivers belonging to the Triassic Burano formation. The evaporitic layers, up to one hun-dred meter thick were probably crucial for the strong tectonic displacement of this igneous sequence. Per-vasive alteration produced the replacement of primary mineralogy with hydrothermal minerals. The in -crease with depth of epidote content and other hydrothermal alteration products of the deep-seated Pieve S. Stefano volcano supports the idea that the original eruptive sequence might have been preserved. Three samples of decalcified andesite grains from core interval 3864 – 3872 m yield radiogenic 40Ar contents of (1.333, 1.179, 1.012) x 10-3 mm3/gram. Apparent ages of 33.8, 30.0, 25.7 Ma are obtained by K2O content of 1.21 %. Precisely repeated datings are not to be expected from the altered rocks of Pieve S. Stefano. If the average date of 29.8 Ma is a true date, it indicates the approximate timing of alteration rather than that of eruption.Start of WNW-directed subduction and the “lost volcanoes”.Start of WNW-directed subduction and the “lost volcanoes”.

Overall, postorogenic lithosphere rupture and volcanism of calc-alkaline nature produce alternance of fault-bounded horst, exposing crystalline-metamorphic and volcanic rocks, and grabens that contain thick deposits of volcanoclastic and siliciclastic nature (Stewart, 1978; Hawkesworth et al., 1995; Hooper et al., 1995). Calc-alkaline volcanoclastic deposits of Oligocene – Burdigalian age are found as allochthonous bodies in the Apennines in the absence of volcanic emission centres (Fig. 3). This geotectonic reconstruction considers that, at the nascence of WNW subduction and thrusting beneath the Apennines (ca. 16/15 Ma), the submerged Tyrrhenian OAA, source area of the allochthonous volcanoclastics was probably affected by commencement of inversion tectonics in which compression follows the extension-dominated phase. The fate of the volcanoclastics could have been determined by a

significant change of tectonic mode in their former sites of origin. By the start of WNW subduction, inversion tectonics could initiate the down-faulting of the original horst volcanoes (past topographic highs) and the thrusting of the fault-bounded grabens bearing volcanoclastic deposits (former lows). Rupture of the original upper plate horst-graben architecture probably initiated gradual downdrag and upthrust motions which were at the origin of the loss of the original topographic highs (volcanic horsts) and preservation of the lows (fault-bounded grabens bearing volcanoclastic deposits). In the more orthodox concept of West-Mediterranean-Tyrrhenian evolution, the persistent WNW subduction of the last 33/32 Ma excludes horst-graben inversion in which a contractional phase follows the extensional phase.

Supplementary –Table S4: Table of revisited geochemistry and age data of calc-alkaline volcanics showing Oligocene to Langhian/Tortonian age (west Mediterranean re-gion); major oxides (weight %) and trace elements (ppm). European plate; data source: 1) Ryan et al., 1972; 2) Civetta et al., 1978; 3) courtesy of H. Bellon; 4) Savelli et al., 1979; 5) Bellon, 1981; 6) Montigny et al., 1981; 7) Marti' et al., 1992; 8) Beccaluva et al., 1994; 9) Morra et al., 1994; 10) Argnani et al., 1995; 11) Conti, 1997; 12) Morra et al., 1997; 13) Rossi et al., 1998; 14) Mattioli et al., 2000; 15) Downes et al., 2001; 16) Mascle et al., 2001; 17) Ottaviani et al., 2001; 18) Franciosi et al., 2003; 19) Conticelli et al., 2007; 20) Conticelli et al., 2009. Alboran-Betic segment of OAA; data source: 21) Torres Roldan et al., 1986; 22) Di Battistini et al., 1987; 23) Benito et al., 1999; 24) Hoernle et al., 1999; 25) Turner et al., 1999; 26) Duggen et al., 2004; 27) Gill et al., 2004. African segment of OAA; data source: 5) Bellon, 1981; 28) Belanteur et., 1995; 29) Louni-Hacini etal., 1995; 30) El Bakkali et al., 1998; 31) El Azzouzi et al., 1999; 32) Fourcade et al 2001; 33) Maury et al., 2000. Serial affinity: hK-CA = high potassic calc-alkaline; HAB = high alumina basalt; HMB = high magnesium basalt; mK-CA = medium potassic calc-alkaline. OAA = (Mediterranean) orogen of Alpine age. Geological age: Ol-Aq = Oligocene – Aquitanian (33/32-20 Ma); Burd = Burdigalian (20-16 Ma); Bu/La = Burdigalian/Langhian transition (16-14 Ma); La - L. Mio = Langhian - late Miocene (15-8 Ma).

Table S4. Location Site, Fig. 3 Rock type Note Ser. affinity Sample Age Data Wt.% SiO2 TiO2 Al2O3 Fe2O3 FeO MnO MgO CaO Na2O K2O P2O5 LOI Sum ppm Rb Sr Y Zr Nb Ba Th La Ce Nd Sm Eu Gd Dy

European plate sourceValencia basin 1 dacite pyroclastic mK-CA DSDP/ Ol-Aq 1 68,17 0,23 12,75 2,75 0,02 2,02 0,73 2,40 3,22 8,37 100,66 73,9 148 57,5 10,9 0,20Valencia basin 1 rhyolite pyroclastic /123/2/6 Ol-Aq 1 70,47 0,24 12,37 1,99 0,02 1,19 0,69 2,98 3,76 6,70 100,40 58,2 115 44,5 8,6 0,11Mallorca isl. 18 rhyolite PO-5 Burd 7 71,00 0,21 12,08 0,47 0,84 0,01 0,24 0,71 3,13 4,84 0,01 6,28 99,82 31,2 65,2 126 45,2 0,20Provence, Esterel 3 andesite 77S4F Ol-Aq 3; 5 61,60 0,39 18,20 4,45 0,10 1,70 4,10 4,45 1,71 0,17 2,95 99,82 53 335 7,8 39 12 630 2,4 15 26 11,4 0,7 1,4"; Esterel 3 dacite subvolcanic mK-CA Est 96-2 Ol-Aq 3; 5 63,00 0,43 18,00 4,25 0,19 1,69 5,01 4,75 1,21 0,19 1,49 100,20 37 350 8,2 54 14 472 2,4 16 30 13 0,8 1,4"; Agay 3 dacite mK-CA PR4 Ol-Aq 8 64,67 0,44 17,56 0,50 2,99 0,11 2,12 5,06 5,02 1,28 0,24 1,81 101,80 46 383 7 68 21 501 5 12 40" ; Esterel 3 gabbro xenolith in dacite PR7a Ol-Aq 8 46,59 2,13 16,68 1,61 9,63 0,29 9,19 10,7 2,32 0,33 0,53 2,53 102,52 6 290 35 104 17 183 2 18 37" , near Nice 4 andesite lava clast mK-CA PR2 Ol-Aq 5; 8 58,80 0,96 19,16 0,72 4,32 0,28 2,28 7,98 3,81 1,38 0,29 1,41 101,39 37 367 28 104 8 431 5 10 24

Sardinia; Sarroch 5 basalt amphibole- SH-32 Ol-Aq 11 51,65 0,85 18,48 4,18 4,77 0,23 5,12 8,37 2,67 0,62 0,16 2,79 99,99 16 284 12 88 5 307 16,2 31,7 14,8 3,5 1,11 3,46"; Sarroch 5 bas. andesite bearing SH-55 Ol-Aq 11 55,51 0,65 18,05 2,47 5,21 0,17 3,79 8,32 2,43 0,76 0,16 2,48 100,00 33 367 18 92 6 383 3,98 24 44,7 23,5 5,2 1,4 5,9"; Sarroch 5 andesite SH-48 Ol-Aq 11 60,19 0,61 17,99 2,61 3,22 0,16 2,20 7,94 3,08 1,20 0,15 0,66 100,01 54 315 21 105 4 495 2,76 20,1 39,7 18,1 3,9 1,17 4,20"; Bosano 8 bas. andesite mK-CA A530 Ol-Aq 8 53,5 0,84 20,18 1,21 7,3 0,2 3,6 9,52 3,05 1,1 0,3 0,83 101,5 26 325 20 75 6 203 2 11 29"; Arcuentu 21 bas. andesite breccia mK-CA ST81 Burd 15 56,45 0,85 16,84 7,88 0,15 5,33 8,89 2,18 1,47 0,17 0,68 100,89 47 263 28 142 8 599 7,3 25,3 55,3 26,9 5,0 1,13 5,20"; Arcuentu 21 andesite hK-CA ST138 Burd 15 62,64 0,78 16,06 5,30 0,08 2,59 5,64 2,83 2,88 0,12 1,40 100,32 132 180 31 168 11 545 11,8 27,4 57,0 26,1 5,0 0,99 4,84 4,65"; Arcuentu 21 basalt dike tholeiite ST46 Burd 15 50,52 0,57 14,39 10,49 0,18 9,94 9,90 1,86 0,58 0,09 0,72 99,24 18,1 193 15,4 37,0 1,8 128,0 2,2 4,6 11,4 6,4 1,79 0,61"; Arcuentu 21 " tholeiite AR2b; a501 Burd 4; 10 50,58 1,03 17,90 1,49 8,96 0,19 5,52 10,3 2,07 0,80 0,30 1,99 101,17 19 291 20 58 5 143 7 16"; Arcuentu 21 " tholeiite AR 280 Burd 18 51,11 0,75 15,21 9,76 0,18 9,28 10,0 1,96 0,54 0,09 1,09 100,00 13,3 192 17,5 50,4 2,4 153,0 2,2 6,55 14,10 7,91 2,20 0,78 2,58 2,91"; Villanovaforru 21 " porphyric low-K CA VF2B Burd 14 49,5 1,57 14,1 10,35 - 0,1 11 8,01 1,81 1,2 0,21 1,46 98,98 19 396 15 41 5 61 0,5 18 14"; Villanovaforru 21 " doleritic low-K CA VF2C Burd 14 47,1 1,71 15,26 9,51 - 0,2 11 9,89 2,35 1 0,2 1,15 99,61 9 413 20 35 8 59 13 15"; Marmilla 21 " tholeiite A 714-713 Burd 4; 8 52,1 0,76 17,14 1,16 7 0,1 5,9 10,8 1,79 0,3 0,18 2,98 100,2 11 302 17 51 5 177 2 8 20"; Montresta 21a " thol./HMB kb 24 Burd 6; 12 47,4 0,79 15,19 10,43 - 0,2 11 11,9 2,14 0,5 0,26 0,32 100,00 7,1 450 16 38 2 49 1,1 4,2 10,5 7,93 2,26 0,8 2,3 2,4"; Montresta 21a " HAB/mK-C kb2 Burd 14 47,5 0,91 16,55 11,40 0,21 5,95 11,5 2,18 0,90 0,28 2,66 100,00 21 394 19 51 5 120 6,9 16,5 10,6 2,86 1 2,7 3,2"; Anglona 22 andesite hK-CA A540 Burd 8 61,6 0,74 16,29 0,92 5,5 0,2 2,4 5,1 2,43 3,1 0,21 3,77 102,3 18 253 26 107 9 373 5 23 51"; Anglona 22 latite hK-CA Al 1 Burd 4; 8 58,4 0,78 18,37 0,84 5,1 0,1 1,8 7,09 3,09 3,7 0,28 1,71 101,3 137 414 23 171 12 353 13 26 54"; Anglona 22 rhyolite ignimbrite SI-2 Burd 3 65,1 0,5 14,9 4,10 - 0,1 1,4 3,4 3,4 3,7 0,1 3,2 99,9 155 230 13 678 34 74 6,9 1,1Sulcis 22b rhyol/com " NU371 Burd 9 70,17 0,43 14,47 3,04 0,26 0,03 0,41 1,26 4,05 5,14 0,08 0,66 100,00 191 139 42 442 31 872 61 109 54,3 11,2 1,3 9,1 9,1S. Antioco 44 comendite comendite 37/Fbis Bu/La 9 72,10 0,32 11,80 4,39 0,36 0,13 0,22 0,20 5,08 4,82 0,04 0,55 100,01 258 11 96 1120 132 103 111 210 94,9 21,1 1,1 17,4 16,6"; SE offshore 45 shoshonite shoshonite Sar1.03 La-L. Mio 16 60,3 0,31 17,94 2,17 - 1,1 2,57 5,48 5,7 0,13 3,47 99,12 100 156 7,5 127 13 412 35 59,8 19,7 2,79 0,6 2 1,6Corsica; Balistra 23 rhyolite pyroclastic hK-CA B13 Burd 17 73,3 14,53 0,9 1,99 3,59 3,3 138 123 12 128 8 11 22 37,9 12,4 2,12 0,5 1,8 1,9"; SW offshore 24 andesite amphibole+biotite bear. DR02 Burd 13 41,00 0,49 18,45 3,85 0,1 8,7 4,50 3,36 4,05 0,20 14,5 99,17 58 78 13 170 5,1 226 21 42 77,3 28,9 5 1,2 3,9 2,8Alpine Corsica Sisco 46 lamproite sill lamproite sis04 Bu/La 19, 20 58,5 2,27 10,8 0,81 2,4 0,1 6,6 3,12 1,02 11 0,67 2,09 99,09 380 803 27 1309 63 1310 172 347 139 19 3,2Alboran-Betic segment of OAAAlboran region ODP site 977 15 granite 7646 Burd 24; 26 70,5 0,24 15,13 t. 2.25 0,04 1,44 2,77 2,48 3,86 0,08 1,01 99,76 245 82 11 74 10 168 8,5 13 28,2 11,8 2,95 0,6 2,7 2,2Alb. ridge 26 rhyolite hK-CA CYA3-11 La-L. Mio 27; 26 68,44 0,23 14,73 t. 2.09 0,04 0,42 2,36 3,66 4,1 0,05 3,72 99,85 169 240 28 189 12 796 18 35 72 32 5,91 1 4,5 4,4Alb. Island " bas. andesite tholeiite 2002 La-L. Mio 27 55,5 0,54 16,84 t. 8.86 0,16 5,66 9,61 1,91 0,22 0,16 0,53 99,95 4 99 30 26 <0.3 21 2,5 6,5 6,05 2,13 0,7 3,1 4,2Yusuf ridge 26 andesite tholeiite CYA 5-6 La-L. Mio 26 60,20 0,65 15,30 t. 8.06 0,15 3,76 8,31 2,33 0,3 0,07 0,76 99,90 11 70 22 48 0,6 14 0,50 1,80 4,90 4,50 1,76 0,62 2,66 3,56Mansour smt " bas. andesite tholeiite POS III-D-1 La-L. Mio 26 51,50 0,87 20,10 t. 8.40 0,15 3,82 10,9 2,25 0,4 0,08 1,37 99,80 9 135 21 59 1,2 27 0,80 3,80 8,90 6,70 2,23 0,83 2,88 3,57ODP site 977 " rhyolite 7521 La-L. Mio 24; 26 72,9 0,23 14,17 t. 1.76 0,01 0,48 1,70 3,57 4,62 0,07 0,56 100,10 167 187 17,4 178 11 880 19 44 88,6 35,4 6,58 1,2 5 3,8" " basalt 7523 La-L. Mio 24; 26 49,9 0,77 18,29 t. 7.85 0,07 6,48 10,6 2,70 0,28 0,15 2,24 98,80 < 4 385 20,9 83 4 82 6,6 13 39,7 17,3 4,6 1,2 4,6 4,5Betic region Malaga 14 bas. andesite dike tholeiite AM240699- Burd 26 54,9 0,47 16,60 t. 5.88 0,10 6,26 8,83 2,97 0,65 0,06 2,84 99,60 23 237 20 62 1,9 135 2,7 7 15,3 7,92 2,04 0,6 2,2 2,4Malaga basalt " tholeiite CB230699- Burd 26 52,8 0,68 16,70 t. 7.60 0,17 6,52 9,84 2,41 0,65 0,07 2,39 99,90 20 231 15 56 1,7 79 0,7 3,3 8,02 5,4 1,68 0,6 2,1 2,4Malaga basalt " tholeiite M2 Burd 25 53,2 0,83 15,74 t. 9.62 0,18 5,13 9,45 2,43 0,30 0,08 3,05 100,05 14,4 170 19 37,5 1,9 50 0,7 2,9 7,63 6,54 2,11 0,8 2,8 3,1Malaga basalt " tholeiite IB 18 21 50,9 0,48 15,53 2,07 6,13 0,16 7,28 11,9 2,41 0,36 0,06 2,67 100,00 9,5 155 18 64 0,6 3,3Malaga bas. andesite " tholeiite IB 44 21 55,8 0,76 15,62 1,43 6,99 0,16 4,96 8,76 2,78 0,76 0,08 1,91 100,02 35 161 72 72 0,9 9,4Malaga 14 granite " MI22; 0699- Burd 26 74,0 0,11 14,4 t. 1.09 0,04 <0.03 0,66 2,67 5,20 0,18 0,49 98,90 455 50 12 47 105Malaga bas. andesite " FG22; 0599-2 26 53,1 0,47 16,50 t. 5.54 0,10 9,09 10,3 1,76 0,94 0,07 1,68 99,50 60 196 35 62 11 113 13 34 71,9 31,7 6,88 0,9 6,2 5,9Mar Menor 17 dacite, cordierite bear. MM2703 Burd 26 60,90 0,64 15,70 t. 5.42 0,08 4,75 4,96 1,61 2,24 0,15 2,25 98,70 127 162 23 133 331Mazarron 28 basalt mK-CA B302 La-L. Mio 25 52 1,75 12,80 t. 14.50 0,1 4,6 8,38 3,72 0,8 0,24 1,00 99,89 28,3 305 36 15,5 10 1172 2,8 18 39,0 23,6 5,81 1,8 6,7 3,3Mazarron latite shoshonite MAZ 8 23 64,2 0,63 16,22 0,81 3,26 0,1 1,6 2,57 2,25 4,4 0,42 3,39 99,80 227 581 31 260 33 1310 64 64 137 68,2 12,4 2,3Cabo de Gata 27 andesite breccia mK-CA CG200; 599 La-L. Mio 26 57,2 0,63 15,80 t. 7.47 0,15 5,77 9,21 1,87 0,94 0,11 0,83 99,90 46 185 19 76 4,1 134 3,32 11,1 23,5 12,4 2,98 0,73 3,03 3,18Cabo de Gata bas. andesite pyroxene be mK-CA Sp317 La-L. Mio 22 54,7 0,73 18,25 4,49 4,20 0,2 4,9 8,9 2,14 0,8 0,15 0,61 100,00 29 310 20 56 5 334 2Cabo de Gata andesite amphibole b hK-CA Sp333 La-L. Mio 22 62,1 0,63 17,76 2,51 0,80 0,1 1,4 3,54 3,76 5,4 0,17 1,91 100,02 195 230 24 145 7 473 8Cabo de Gata dacite hK-CA Sp253 La-L. Mio 22 65,4 0,55 15,86 2,22 1,31 0,2 1,5 1,03 1,78 8,1 0,13 1,86 100,00 352 108 32 190 9 383 9African segment of OAAMorocco, RifRas Tarf 29 andesite mK-CA 116-72 La-L. Mio 31 57,60 0,65 16,4 t. 7.2 0,1 4,7 8,03 2,45 1,5 0,17 1,24 100,03 51 280 20 110 6,8 685 20 38 20 1 3,5Trois Forches 30 rhyolite hK-CA G44 La-L. Mio 30 72,3 0,27 13,65 t. 2 0 0,3 1,63 3,80 4,2 0,99 99,06 148 162 25 159 13 774 15 35 72,5 28,1 5,75 1,4 5,9 4,6Gourougou close to granodiorite hK-CA G1 La-L. Mio 30 59,15 0,57 14,75 t. 6.85 0,02 3,90 3,89 2,40 3,30 4,54 99,37 85 410 26 127 14 974 12 46,2 85,0Gourougou s. 30 andesite hK-CA G8 La-L. Mio 30 61,00 0,75 16,50 t. 4.65 0,06 1,78 5,75 3,12 2,87 3,24 100,31 280 540 24 212 15 33Gourougou andesite hK-CA G15 La-L. Mio 30 61,00 0,70 16,35 t. 4.7 0,1 2,4 5,6 2,88 3,9 0,24 1,88 99,62 191 380 21 203 18 1531 19 30 55 25 4,6 1,2 3,6Gourougou shoshonite shoshonite G47 La-L. Mio 30 53,97 1,05 17,06 t. 8.19 0,1 4,9 8,99 3,10 2,95 0,05 100,36 118 564 26 124 33 913 12 32,4 63,4 26,1 4,63 1,20 4,06 3,45Gourougou absarokite G74 30 49,70 1,29 17,10 t. 8.62 0,10 4,72 10,6 2,98 2,39 3,02 100,52 74 545 20 106 33 14 28,4 53,4 23,6 4,35 1,25 4,00 3,46AlgeriaSahel d'Oran 31 andesite dike hK-CA OR10 La-L. Mio 29 56,70 0,68 14,90 t. 6.97 0,12 5,86 7,47 3,17 2,59 0,21 1,37 93,07 85 570 24 141 7,2 850 43 87 37 1,50 3,90M'Sirda 32 dacite/latite dome shoshonite ORbd1 La-L. Mio 29 61,60 0,70 16,65 t. 3.51 0,08 2,10 4,56 2,70 4,48 0,41 2,88 96,16 182 892 20 148 20 2300 63 123 60 2,15 3,90Middle Tafta 33 alk. basalt Na-alkaline OR13 La-L. Mio 29 45,90 1,49 15,68 t. 9.50 0,15 9,57 9,25 3,15 0,69 0,48 3,81 99,67 12 775 20 146 21 655 24 54 31 1,70 3,40Dellys 19 tholeiite th/CA DLDR Burd 28 46,90 0,76 0,68 t. 9.30 0,16 9,00 10,7 1,88 0,36 0,13 5,18 100,52 5 200 18 46 3 77 5 12 7 0,8 2,8Dellys basaltic andesite low-K CA DLBO La-L. Mio 28 55,70 0,98 18,00 t. 7.76 0,27 2,81 8,02 3,50 0,46 0,10 1,99 99,69 4,1 400 26 84 3,7 127 9,1 21 13 1,1 4Cap Djinet 36 basalt DJ1 La-L. Mio 28 46,30 0,78 16,80 t. 9.4 0,13 8,70 10,5 2,58 0,64 0,19 4,21 12,1 340 17 41 2,5 106 5 12 8,5 0,8 2,5Cap Djinet " " DJ2 La-L. Mio 28 47,80 1,00 17,15 t. 9.9 0,16 6,55 9,35 3,35 0,38 0,19 3,82 99,65 6,7 360 22 68 4,1 113 8,4 19 11,5 1,1 3,5Thenia 10a granodiorite T22 Bu/La 28 64,20 0,45 16,6 t. 4.41 0,04 2,4 3,96 2,67 3,4 0,15 1,3 99,55 245 192 14 100 7,4 235 18 33 0,9 2,6Thenia 10a rhyolite T36 La-L. Mio 28 73,20 0,18 12,95 t. 1.73 0,01 0,4 0,61 1,91 6,3 0,03 1,35 98,85 296 43 14 73 9 361 21 30 16 0,5 2,7Bejaia-Amizour 11 quartz-monzonite hK-CA/sho A12 Burd 32 62,00 0,69 16,1 t. 5.55 0,33 1,4 1,98 4,28 5,1 0,16 1,66 99,26Bejaia-Amizour 11 granite A1 32 68,20 0,42 14,85 t. 3.35 0,06 1,1 2,57 3,72 4,2 0,08 0,86 99,47SE of Amizour 11 diorite A9 Bu/La 32 63,20 0,6 15,28 t. 4.44 0,05 2,3 4,66 3,43 3,8 0,12 1,82 99,69Cap Bougaroun 12 crd-granite U3 Burd 32 69,2 0,44 15,06 t. 3.06 0,05 1,5 2,42 2,65 3,9 0,14 0,90 99,39 219 139 23 148 11 361 30 71 29,9 5,5 1,1 4,7" 12 crd-granite L61 32 69,4 0,42 15,83 t. 3.01 0,05 1,1 2,29 2,88 3,7 0,14 0,92 99,73 226 175 17 143 14 300 27 62 26,9 5,1 1,1 4,2" 12 rhyolite hK-CA C1 32 73 0,12 14,68 t. 1.46 0,02 0,3 0,65 3,31 4,8 0,29 0,66 99,21" 12 gabbro L44 32 47,6 0,73 17,11 t. 9.17 0,16 7,4 11,9 1,5 0,8 0,16 2,80 99,37 27 269 15 45,5 1,4 182 5,6 12,7 7,4 2,08 0,7 2,3Djebel Filfilla 32 crd-granite II 6 Bu/La 32 72,2 0,28 14,62 t. 1.98 0,02 0,6 1,04 3,12 4,7 0,18 0,72 99,46 427 60 13 125 17 226 25 65 28,6 5,5 0,6 4,6Cap de Fer 38 gabbro VPE-271 32 47,80 0,35 14,8 t. 8.62 0,19 14 8,6 1,16 1,7 0,08 2,21 99,40 111 197 9,2 42,9 1,8 159 7,7 15,4 7,1 1,72 0,5 1,8 1,6" 38 basalt mK-CA VPE-21 32 51,4 0,58 16 t. 7.14 0,09 8,1 9,3 2,06 1,3 0,12 3,96 100,03 56 294 14 70,5 2,9 149 12 24,3 11,2 2,4 0,8 2,4 2,3Tunisia La Galite isl 41 granodiorite hK-CA La-L. Mio 33

Supplementary – Table S5: Table of site, formation, age and stratigraphic data of calc-alkaline volcanogenic allochthonous sediments from the Apennines and the Maghrebid-Betic region. Key: SIV, stratigraphic interval with volcanogenic sediments (meters); VTT, total thickness of volcanoclastic beds; TVB, thickest volcano-genic bed. Fig. 3: elongated triangles without black rim of red, gray and yellow colour indicate beds of Oligo-cene-Aquitanian, Burdigalian and Langhian-Tortonian age. References.- [1] Guerrera et al. 1998 and references therein; [2] Guerrera et al. 2005 and references therein; [3] Critelli et al., 1990; [4] Maate et al., 1995; [5] Riviere et al., 1977; [6] Balogh et al. 1993 and references therein; [6a] Critelli et al., 1990a; [7] Spadea et al. 1974; [8] Le Pera et al., 1994; [9] Balogh et al., 2001; [10] Borsetti et al., 1984; [11] Guerrera et al., 1993 and references therein; [11a] Perrone, 1987; [12] de Capoa et al., 2002; [13] Baruffini et al., 2002; [14] Faugères et al., 1992; [15] Delle Rose et al.,1994a and references therein; [16] Crisci et al., 1988; [17] Mattioli et al. 2002; [18] Cibin et al., 1998; [19] Tateo, 1993; [20] Mezzetti et al., 1964; [21] Cibin et al., 2001; [22] Amorosi et al., 1994; [23] Coccioni et al., 1988; [24] Guerrera, 1977; [25] Guerrera et al.,1986; [26] Delle Rose et al., 1994b; [27] Guerrera et al., 2004; [28] Mattioli et al., 2000.

SECTOR,

DOMAIN, SITE

(Fig. 3)

FORMATION AGE

VOLCANOCLA

STIC ROCK

TYPE

VOLCANIC LAY-

ERS (type, SIV,

VTT, TVB

(meters)

SEDIMENTARY

PROCESSES

VOLCANIC

SOURCE

HYPOTH.

MAIN

REFER

-ENCE

Betic

Cordillera/ 1

Viñuela

Group

early

Burdigali

an

andesite, rhyolite-

rhyodacite

fragments

mineral grains and

glass- shards; SIV: 45;

VTT: 3;

pyroclastic fallout;

epiclastic mass-flow

(turbiditic)----

[1]

[2]

Betic

Cordillera/ 2

Algeciras

Flysch

Aquitanian

Burdigalian

p.p.

andesite, rhyolite

fragments

felsitic lava and mineral clasts

(up to 7% vol.)

epiclastic mass-

flow (turbiditic)----

[1]

Betic

Cordillera/ 3

Almidar, Río

Fardes-Mencal

Succ.b (Sub-

betic)

early

Burdigalian

rhyodacite

fragments

glass-shards and

mineral grains; TVB: 0.25

Epiclastic mass-

flow (turbiditic)

Submarine

volcanic

emissions

Rif / 4Sidi Abdeslam

–Boujarrah Fm

Early

Burdigalianandesite, basalt

mainly mineral clasts, SIV:

10; VTT: 0.5; TVB:0.15

epiclastic mass-flow

(turbiditic)

Internal

zones

[1]

[4]

Rif / 5Beni Ider

Flysch

late Aquitanian

-early

Burdigalian

andesite,

basalt fragmentslava clasts

syn- and/or post-

eruptive epiclastic

mass-flow (tur-

biditic)

Internal

zones

[1]

[6]

[2]

Rif / 6

Talaa Lakra

(Mixed

Successions)

late Aquitanian

-early

Burdigalian

andesite

fragmentslava clasts

syn- and/or post-

eruptive epiclastic

mass-flow (turb.)

Internal

zones

[1]

[6]

Algerian

Tell/ 7, 8

Oligo-Miocène

Kabylia

Burdigalian p.p

(19.1±1.0 Ma)rhyolite

glass-shards; grains of quartz,

plagioclase, sanidine, biotite

epiclastic mass-flow

(turbiditic)

Western

Mediterran

[11]

[5]

Sicily/ 9Tusa

Tuffites

;

early

Oligocene

andesite to dacite

fragments

lava clasts (80-85% vol.),

grain size up to 2.5 mm, SIV:

600; VTT: 200; TVB: 1.5-2

epiclastic mass-flow

(turbiditic)

Mesomedi-

terranean

Microplate

[2]

[1]

[12, 13]

Sicily/ 10Troina

Sandstones /Burdigalian pp.

andesite

fragments /

up to 40 % volcanic clasts,

grain size >2 mm; SIV: 150,

epiclastic mass-flow

(turbiditic)

Mesomedit.

Microplate

[2]

[6]

Poggio Maria

Sandstones

volcanic glass,

andesite-dacite

fragments

VTT: 30-40; TVB: 0’5-1 /

lava and mineral clasts (30-

35% vol.), grain size >2

mm;

SIV: 200; VTT: 30-35; TVB:

0’5-1,5

[12]

Sicily/ 11*

Case Liardo,

M. Ugliarella;

C. Biticchie

mid Miocene rhyodacitic glass

shards, biotite; bentonite

clays (TVB: 1-1.5); rhyoda-

citic tuff (TVB: 0.5-1.5)

Volcanic arc [7]

Sicily/ 12mixed

successions

late

Aquitanian

early

rhyolite, andesite,

basalt fragments

mainly lava clasts, grain

size>2 mm, SIV:43;

TVB:1

epiclastic mass-flow

(turbiditic)---

[1]

[11]

Sicily/ 13*

Reitano flysch;

mixed

successions

early

Oligoce

ne

arenitic beds; an-

desite & basalt

fragments

lava and mineral clasts,

glass-shards, pumices,

SIV:20

epiclastic mass-flow

(turbiditic)----

[9]

[11,14]

Calabria-

Peloritani

Arc / 14

Stilo-Capo

d’Orlando,

Paludi

early

Oligoce

ne

andesite & basalt

rock fragments;

crystals

lava and mineral clastsepiclastic mass-flow

(turbiditic)

Internal

zones

[1]

[2]

S. Apennines

/ 15

Calabro-

Lucano

Liguridi

Complex)

late

Oligoce

ne

andesite, basalt,

rhyodacite

fragments

Lava and mineral clasts,

glass-shards (andesite,

qz- andesite

tuffites),TVB:1.5

epiclastic mass-flow

(turbiditic)

Active

volcanic arc[15]

S. Apennines

/ 16

Saraceno

(Liguridi

Complex)

early

Mioce

ne

andesite to dacite

fragments; mineral

clasts

lava and mineral clasts

(andesite, qz andesite

tuff)

epiclastic mass-flow

(turbiditic)

Active

volcanic arc

[1]

[2]

[3]

S. Apennines

/ 17

Tusa Tuffites

complex

(Sicilide

Complex)

early

Oligoce

ne

andesite, basalt,

dacite fragments

lava and mineral clasts

(80%vol.), pelites with

pumices, glass-

shards;SIV:54;

VTT:46;TVB:5

epiclastic mass-flow

(turbiditic) and ash

turbidites

Sardinia

[11]

[13

[2, 3]

S. Apennines

/ 18

Numidian

Flysch

late

Burdigalia

n-

-early

Langhi

rhyoliteglass-shards, mineral

grains, pumices, lava

clasts

Pyroclastic fallout Sardinia [11]

S. Apennines

/ 19

Pollica

(Cilento

Group)

Burdigalian-rhyolite,

rhyodacitelava and tuff clasts, TVB: 3

epiclastic mass-flow

(turbiditic)Sardinia [6, 6a]

S. Apennines San Mauro/ Burdigalian rhyolite, lava and mineral clasts; SIV: mass-flow short- Sardinia- [16]

/ 20* Pollica

(Cilento)

rhyodacite 15-20 distance (turbiditic) -Corsica [11]

S. Apennines

/ 21

Mt. Soprano

(Daunia

Complex)

late

Burdigalian

andesite and/or

basalt fragments

3-15 % lava clasts; mineral

grains, glass-shards; TVB: 5

pyroclastic fall-out,

epiclastic mass-flow

(turbiditic)

Volcanic

Arc

(Sardinia)

[11a]

S. Apennines

/ 22*

Macchialupo;

Gorgoglione

(Daunia comp)

Burdigalian

p.p.; Miocene

andesite and/or

basalt fragments;

rhyolite clasts

lava clasts (70-90 % vol.),

SIV: 80; TVB: 4

epiclastic mass-flow

(turbiditic)

Volcanic

Arc

(Sardinia)

[6]

[8]

N. Apennines

Sub-Ligure Do-

main / 23

[*]

Val Aveto;

Ranzano

Early

Oligocene

basalt, andesite,

dacite, dacite-

rhyol. ignimbrite

clasts

lava clasts

(up to > 80 vol. %)

SIV: 490

epiclastic mass-flow

(turbiditic)

Continental

arc (near the

graben)

[17]

[18]

N. Apennines

Sub-Ligure Do-

main / 24*

Petrignacola;

Ranzano

early

Oligocene;

32-30 Ma

basalt, andesite,

dacite;

rhyodacite,

ignimbrite clasts

volcanic clasts

(up to > 80 vol. %); SIV: 255

epiclastic mass-flow

(turbiditic)

Continental

arc (near the

graben)

[17]

N. Apennines

Epi-Ligure Do-

main / 25*

Antognola

Ranzano

Mongardino

early

Oligocene;

32-30 Ma

andesite, dacite;

glass-shards

(rhyolite- rhyo-

dacite)

lava and mineral clasts; glass-

shards; SIV: 15; VTT: 5;

TVB: 5

epiclastic mass-flow

(turbiditic)----

[19]

[20]

[1]

[21]

N. Apennines

Epi-Ligure Do-

main /

26/*

Tripoli di

Contignaco

Aquitanian-

Burdigalian

p.p.; 22.4 Ma

rhyodacite-dacite

clasts

glass-shards (< 90% vol.),

mineral clasts (grain size <

0,5 mm), SIV: 15; VTT: 15;

TVB: 10

pyroclastic fallout,

and/or epiclastic

mass -flow, hyalo-

clastic

----

[6]

[10]

[22]

N. Apennines

/ 27[*]

Bisciaro

Formation

(s.s.)

Burdigalianandesite –

rhyolite

glass-shards, mineral and lava

clasts; SIV: >100; VTT:18;

TVB: 6.9

epiclastic mass-flow

(turbiditic) and

pyroclastic fallout

Intern. volc.

zone (near

the graben)

[1] [5]

[23]

[24, 25]

N. Apennines

/ 28Cervarola

Aquitanian/

Burdigalian

andesite and

rhyolite

mainly glass-shards, mineral

grains -vitric tuffs, SIV: 80;

VTT: 10; TVB: 6

epiclastic mass-flow

(turbiditic)---- [15]

N. Apennines

/ 29*

Vicchio Marls

(Cervarola

Unit; Bisciaro

form, l.s.)

late Aquitanian

-Burdigalian

p.p. (lower

portion)

rhyolite

-dacite glass

mineral grains, glass-shards

and andesitic clasts; SIV: 450;

TVB: 0.3

epiclastic mass-flow

(turbiditic)

internal

volcanic

zone (near

the graben)

[15]

[26]

W-Sardinia

Graben / 30

Villanovaforru

Succession,

Marmilla

Basin

Burdigalian

high-Mg basalt

(tholeiitic/calc-

alkaline type)

large amount of reworked

volcanic detritus, SIV: 640;

VTT>10; TVB: 0,6

epiclastic mass-flow

(turbiditic), pyro-

clastic fall.

close to the

source

[27]

[28]

Supplementary – Table S6: Table of revisited age and geochemistry data of Apenninic allochthonous volcanoclastics and buried volcano beneath Pieve Santo Stefano; major elements (weight %) and trace elements (ppm). Data source: 1) Eni (unpublished report, 1982; 2) Cibin et al., 1998; 3) Balogh et al., 2001; 4) Baruffini et al., 2002; 5) Mattioli et al, 2002; 6) Mezzetti et al., 1964; 7) Guerrera et al., 1986; 8) Balogh et al., 1993; 9) Delle Rose et al., 1994a; 10) Delle Rose et al., 1994b; 11) Spadea and Carmisciano, 1974; 12) Guerrera et al., 1986; 13) Crisci et al., 1988; 14) Critelli and Le Pera, 1990a; 15) Le Pera and Ventura, 1994. CA = calc-alkaline; glass sh. = glass shards; b.d. = below detectio.

Age (Ma) Location Site in Data Rock Note Sample Serial Whole Mineral SiO2 TiO2 Al2O3 Fe2O3 FeO MnO MgO CaO Na2O K2O P2O5 LOI Sum Rb Sr YOligocene Fig. 3 source type affinity rock grains Wt. % ---> ppm --->

North Apennines29.8, 29.0 Aveto & 25-24 5 basalt lava clast MM72 CA wh. rock 48,42 1,04 18,02 9,11 0,14 5,85 9,41 3,49 0,94 0,14 3,43 100,00 36 557 25amphibole Petrignacola " " " MM15 " 49,94 1,05 18,57 11,84 0,14 9,34 1,36 4,13 0,30 0,23 3,11 100,00 38 634 34Ar/Ar dates " basaltic " MM5 " 51,16 1,00 18,38 10,73 0,14 7,75 1,59 5,15 0,42 0,20 3,49 100,00 9 500 26

" andesite " MM2 " 54,49 0,92 16,44 6,54 0,13 3,84 10,41 3,02 1,15 0,17 2,90 100,00 40 338 20" andesite " MM61 " 56,43 0,79 19,71 5,19 0,12 3,83 5,16 3,36 2,60 0,21 2,59 100,00 85 903 23" " " MM109 " 58,03 0,62 17,67 4,91 0,13 3,17 5,67 3,53 2,84 0,16 3,26 100,00 72 730 28" dacite " MM54 " 61,45 0,84 17,68 4,21 0,11 3,14 3,19 4,17 3,61 0,21 1,38 100,00 138 679 23" " " MM89 " 63,75 0,56 16,47 4,59 0,12 3,49 3,88 2,16 3,42 0,18 1,39 100,00 113 614 20" dacite ignimbrite MM29 " 57,50 0,37 16,65 7,07 0,15 5,36 4,02 5,90 0,34 0,16 2,50 100,00 250 32" " clast MM112 " 63,18 0,74 19,02 3,03 0,10 1,26 2,93 4,44 3,50 0,17 1,63 100,00 160 779 27" " " MM113 " 66,23 0,44 15,61 3,78 0,12 2,07 4,11 3,59 2,45 0,18 1,41 100,00 90 427 26" rhyolite " MM114 " 71,42 0,17 12,66 1,50 0,12 2,50 2,40 5,27 1,43 0,21 2,33 100,00 10 183 13

((29.8)) Pieve S. Stefan 13 1 bas. andesite altered 3870-2 CA " 58 0,85 21,2 3,2 0,02 1,30 3,89 3,83 1,63 0,12 6,30(oil drilling) " andesite rocks 3870-1 " 62,1 0,62 15,2 4,54 0,04 1,62 5,02 2,09 2,24 0,11 6,78

Oligocene Ranzano format 26-25 2 andesitic- volcano- 34D CA amphibole 45,18 1,44 9,19 15,73 0,47 12,82 10,98 1,63 0,55(32-30 Ma " " dacite clastic 94 biotite 36,23 4,18 14,53 12,49 0,16 16,04 0,03 0,84 8,56 93,04

" " " 128 pyroxene 52,84 0,18 2,10 8,77 0,77 14,21 22,15 0,28 0,00 101,29NE SicilyReitano flysch 13 3 & 4 rhyolite lava clast 5(24) K- " 64,6 20,2 0,57 0,16 0,11 2,44 11,58 0,08 100,6 (0.34%BaO)

" s 2 alkaline pyroxene 52,46 0,40 1,75 9,84 0,55 14,99 20,06 0,31 100,36

Mioceneearly North ApenninesMiocene Contignaco 26 6 rhyodacite- volcano- 1 CA glass sh. 70,60 0,08 11,67 1,74 0,55 0,06 0,25 1,02 4,50 3,20 6,80 100,47

Mongardino 25 " rhyolite clastic 5 glass sh. 57,87 0,89 14,82 2,97 4,28 0,14 1,34 3,82 2,60 3,51 7,69 99,83" " " 5 wh. rock 58,80 0,99 14,19 3,96 2,83 0,15 1,71 3,75 2,44 3,04 8,64 100,53

Calderino " " " 4 glass sh. 65,1 0,48 14,2 1,69 1,31 0,09 0,80 2,12 3,23 2,87 8,17 100,08" " " 4 wh. rock 60,7 0,56 13,1 3,15 0,98 0,04 1,66 3,30 2,20 1,96 12,85 100,46

Burdigalian Bisciaro formation "(22.3) - 17 Montebello, Urb 27 8 & 6 " " 3 CA glass sh. 65,8 0,58 13,6 1,49 1,5 0,09 0,54 2,18 3,78 2,37 8,28 100,23

Fossombrone 7 " " B6/1 " 67,2 0,28 14 2,55 0,12 0,25 1,26 2,46 4,20 92,26" " " B8/7 " 64,2 0,51 14 3,14 0,10 0,59 3,24 2,54 3,61 91,37" " " B6(2) plagioclas 59,1 27,7 0,38 7,56 7,64 0,76" " " B8(b1) " 50,5 30,5 0,67 15,69 2,75 0,12

Vicchio 29 9 & 10 " " 80 shoshonitic glass sh. 70,6 0,36 14,9 0,68 0,05 2,47 2,21 6,52 97,90" " " " 80a " 75,4 0,53 13,3 0,62 0,88 0,23 0,29 6,93 98,46" " " " 80mc K-feldspar 65,5 0,34 19,3 0,33 0,06 0,30 3,20 11,81 101,63" " " " 80mc plagioclas 59,20 24,88 0,23 6,53 7,02 0,62 94,48" " " " 80mc biotite 34,80 2,49 18,82 21,40 0,20 9,82 0,31 0,44 3,84 92,16

early South ApenninesMiocene Cilento P2O5

San Mauro/ 19, 20 13 &14 rhyodacite lava clast S2 CA wh. rock 68,1 0,35 15,3 3,27 0,07 1,69 1,19 3,09 4,36 0,13 2,44 196 121 8Pollica " " rhyolite " S3 " 76,3 0,05 13,1 1,01 0,02 0,30 0,06 2,72 5,06 - 1,37 137 16 21

Miocene LucaniaGorgoglione 22 15 rhyolite lava clast A II CA " 69,6 0,62 15,3 1,99 2,72 0,04 1,30 0,67 3,11 4,44 0,23 2,06 102,06 240 166 28flysch " " " C 13A " 71,2 0,36 13,6 1,8 2,01 0,05 1,30 0,70 3,39 5,51 0,12 1,51 101,53 191 150 30

" " " B 12 " 75,1 0,19 13,1 0,66 1,35 0,03 0,46 0,78 3,57 4,65 0,07 1,01 101,02 159 55 33mid Mioce Sicily

Case Liardo 11 11 rhyolite volcano- 7 CA glass sh. 68,60 0,23 13,41 0,72 0,92 0,03 0,60 1,85 2,96 3,06 0,12 7,55 100,05 244 115" " clastic " biotite 41,44 3,32 16,05 5,04 11,82 0,17 9,43 0,40 0,73 7,50 0,07 3,86 99,83 672 9

Monte Ugliarella " " " " biotite 38,15 3,56 15,75 11,01 7,09 0,14 10,54 0,41 0,25 7,30 5,86 100,06Case Biticchie " " rhyolite " 14 glass sh. 70,04 0,20 13,34 0,49 0,87 0,05 0,35 1,69 3,11 2,86 0,14 6,87 100,00 251 140

late Mioce North ApenninesLaga Formation 29a 12 rhyolite volcano- F3/9 CA glass sh. 70,84 0,13 13,69 1,18 0,04 0,14 0,96 2,17 2,48 91,36

" " clastic F3/3 andesine 61,50 24,58 0,12 7,29 7,26 0,78 101,53" " " F3/1 labradorite 54,75 27,21 0,18 11,39 5,14 0,35

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