The Apennine foredeep (Italy): a perched isolated basin during the Messinian Salinity Crisis (5.97-5.32 Ma). R. Pellen, S.-M. Popescu, J.-P. Suc, M. Rabineau, M. C. Melinte-Dobrinescu, D. Aslanian, J.-L. Rubino, S. Marabini, N. Loget, W. Cavazza (a) Université de Bretagne Occidentale, IUEM, Domaines océaniques, UMR 6538 CNRS, 1, place Nicolas-Copernic, 29280 Plouzané, France. (b) GeoBioStratData.Consulting, 385, route du Mas-Rillier, 69140 Rillieux-la-Pape, France. (c) Sorbonne Universités, UPMC University Paris 06, CNRS, Institut des Sciences de la Terre de Paris (iSTeP), UMR 7193, 4, place Jussieu, 75005 Paris, France. (d) National Institute of Marine Geology and Geoecology, 23–25 Dimitrie Onciul Street, P.O. Box 34-51, 70318 Bucharest, Romania. (e) TOTAL, TG/ISS, CSTTF, avenue Laribeau, 64018 Pau cedex, France. (f) Museo Geologico Giovanni Capellini, Dip BiGeA, Università di Bologna, Via Zamboni 63, 40126 Bologna, Italy. (g) Via Enrico di S. Martino Valperga, 57, Roma, Italy. (h) Dipartimento di Scienze Biologiche, Geologiche e Ambientali, Università di Bologna, Piazza di Porta San Donato 1, 40126 Bologna, Italy. (i) Department of Earth Sciences, Brock University, 1812 Sir Isaac Brock Way, St. Catharines, Ontario L2S 3A1, Canada. (j) IFREMER, UR Geosciences Marines, BP 70, 29280 Plouzané, France.

1 1 2 3 4 North Apenninic stratigraphy Monticino section Monticino section Maccarone section Civitella del Tronto section Fonte dei Pulcini 5 Roveri et al. (2004, 2005) Sequence Deep Marginal 2- Attempt in dating Fonte la Casa basins basins 20

Samples Ceratolithus 2 acutus U.B.S.U. Argile Azurre Argile Azurre

Samples Ceratolithus 45 4 acutus

Samples

Samples Ceratolithus marine incursions into the acutus 5 5.33 Ma 170 69 Colombacci fm. Samples Colombacci fm.

v Samples 5 40 4 10 Apennine foredeep at the v p-ev2 1 v 8 3 4 1 3 Cusercoli fm. v ? end of the MSC. v 4 80 hiatus

Thickness (m) S. Donato fm. 1 30 1 2 10 5.53 Ma v v 0 (Cosentino 0 0 50 % 100 0 50 % 100 p-ev1 ash layer et al., 2013) v v 0 6 intra-messinian v 0 50 % 100 70 Sapigno fm. unconformity (ex G.S. fm. 150 deep water member) 20 resedimented evaporite 8°E 10°E 12°E 5.6 Ma 60 Vena del Milan Gesso Fm. 1 ? A 0 ‘euxinic 10 3 (ex. Gessoso Solfifera fm. Eroded domain 0 50 % 100 T2 shales’ 50 shallow water member) primary, autochtonous 2 60 Brackish Paratethyan dinoflagellate cysts evaporite) 14°E 130 1 Thickness (m) 40 0 50 % 100 50 Marine dinoflagellate cysts 5.97 Ma Marnoso-arenacea fm. (Manzi et al., 2013) Bologna 40 ‘euxinic shales’ Eroded domain 30 1 Figure 3 Litho- and biostratigraphic correlation between post-evaporitic sections of the Apennine foredeep. 30 Associated with the stratigrapic section, illustration of the Brakisch/marine Dinoflagellate cyst ratio (without 44°N Lowest occurence reworked species) and Ceratolithus acutus occurence. 20 110 of marine 20 Supposed extension of the Eroded domain 1 post-evaporitic deposits Ancona dinoflagellate cysts Supposed extension of the 2 10 Constrains (Popescu et al., 10 evaporitic deposits 2007) Base of the Argille Azurre at 5.33 Ma. p-ev 2 2 Ceratolithus acutus is a biostratigraphically useful calccareous nannofossil species with a short 0 range (between 5.35 and 5.04 Ma; Raffi et al., 2006; Anthonissen and Ogg, 2012). p-ev1 Observation gap ca. 210 m 3 First marine dinoflagellate occurence at 5.36 Ma, correlated with eccentricity and pollen ratio Messinian turbiditic deposits (Laga Basin) Laga (Bache et al., 2012) Basin + Messinian shelf deposit (a) or Pescara 10 Dated ash at 5.532 - 0.00046 Ma (Cosentino et al., 2013) NOSE 01 NOSE 05 a b turbiditic lobe system (b) 5 4 NOSE 07 Resedimented Lower Gypsum (RLG) 5 0 42°N Observation gap ca. 300 m 5 Primary Lower Gypsum (PLG) Gargano Dating marine occurence Miocene sediments Peninsula 0 1 0 50 % 100 Peak 1 marks their lowest occurrence at the boundary between the p-ev1 and p-ev2 formations Mesozoic sediments NOSE 02 (5.36 Ma Popescu et al., 2007; Bache et al., 2012) Peak 2 just follows the lowest occurrence of calcareous nannofossils below the base of the Co- Main Apennine thrust fronts lombacci deposits (5.35 Ma; dated by Raffi et al., 2006) Gargano-Pelagosa paleo-sill 0 70 140 210 km Peak 3 is less prominent and recorded 7 m below the base of the Argille Azzurre (just before 5.33 Ma based on strati-, biostratigraphy and eccentricity). N-NW S-SE Wedge-top basins Foredeep Outer foredeep Foreland ramp Peak 4 begins just below the base of the Argille Azzurre ( ~ 5.33Ma). 1 2 4 Monticino Maccarone 3 Fonte dei Pulcini 5 Civitella del Tronto Fonte la Casa Ma Some definition Ma Ma Argille Azzurre Fm.: Homogeneous clay formation rich in planktonic foraminifera. ATLANTIC2.60 Gargano C 5.332 5.33 5.46 Colombacci Fm.: Two lithological units are described, the lower part is composed of 5.60 5.60 5.36 Argille Azzurre Peninsula 5.97 silt-sand beds alternating with fine clay beds; the upper part observe fine clay beds, Colombacci Colombacci 5.971OCEAN p e v and calcareous beds. Lago mare biofacies is described throughout the formation 5.532 5.36 2 A 5.532 but its palaeoenvironmental formation remain discussed (Roveri et al., 2006; Popescu et al., 2007; Pellen et al., 2017) p e v1 B Cusercoli Fm.: Sand beds at the base followed by fine clay and silt beds. not to scale p-ev1 Fm.: Thick sand turbiditic beds associated with an ash layer (Cosentino et al., Pliocene and Quaternary Messinian Ante-Messinian 2013) Piacenzian and Turbidites and Colombacci unit (p-ev Fm.) ADRIATIC Quaternary clays 2 Messinian Erosional Surface Marnoso-arenacea Fm. Zanclean clays Ash horizon (5,532 Ma) (Cosentino et al., 2013) Primary Lower Gypsum Schlier Fm. (Argille Azzurre) Turbidites (p-ev Fm.)1 Black shales Carbonate platform BASIN b Resedimented Primary Lower Gypsum a Pre-evaporitic Laga Fm. (a, blocks; b, gypsarenite) Figure 2 (A) simplified geological map with location of the studied sections shown in B; (B) schematic geolo- gical section from Romagna to Apulia focussing on Messinian and Zanclean deposits (modified from Roveri Pelagosa DARDANELLES et al., 2008) with correlations between the studied successions.A Sediment thicknessValencia not to scale. LIGURO- B sill BOSPHORUS3- Existence of a palaeo-sill 1- PROBLEMATICS sill PROVENÇAL during the MSC between the The Adriatic Basin (Central Mediterranean Sea) is the place of intense controver- STRAITS sy concerning the sedimentary dynamics and palaeogeographic evolution during the BASIN Apennine foredeep and the Neogene, especially during the Messinian Salinity Crisis (MSC: 5.97 to 5.32 Ma). TYRRHENIAN Otronto deep Ionian basin Following the various interpretations, this basin was totally disconnected or BASIN BASIN sill connected to the deep basins during the MSC sea level fall (~5.60-5.46VALENCIAN (?) Ma). Five stra- tigraphic sections (Fig. 1, 2) have been sampled. Accordingly, much attention has been de- AEGEAN voted to the chronostratigraphic and palaeoenvironmental interpretation (marine versus SEA Brakish dinoyst record; Ceratolithus acutus occu- rence) of Strong dissymmetry is observed between the Central and South Adriatic domains (Figure 4). the sediments deposited in the 10°E 20°E ALGERIAN D Thick Aquitanian-Tortonian and detrital Messinian megase- Apennine foredeepGIBRALTAR after the 0° 5.31 Ma 30°EBASIN quence fill the South Adriatic domain. Pliocene-Quaternary peak of the MSC before Scythian sill megasequence is controlled by the Dinarid deformation the early PlioceneSTRAIT SICILY front. APENN 10°W INE Dacic Basin Pannonian Thick Pliocene-Quaternary megasequence compose the Cen- and marine forma- FO R Basin Euxinic E 40°E D STRAIT tral Adriatic domain. The Laga basin form the main tion (Fig. 1). E Basin B ALBORAN E P Balkans sill syn-MSC depocentre as illustrated Figure 1. ATLANTIC Liguro- Provençal Gargano-Pelagosa Few evaporitic Messinian deposits are observed along the 40°N BASIN Basin Tyrrhenian 40°N Basin sill Egean IONIAN south Apennine front. OCEAN sea Algerian Basin Ionian Basin Crete sill WATER, SEDIMENTARY, AND FAUNA EX- BASIN ATLANTIC Existence of a palaeo-sill formed by the Me- OCEAN Levantine HANGE ARE CONTROLLED BY MOR- Gibraltar sozoic carbonate platform, and Apennine Basin PHOLOGICAL THRESHOLDS sill and Dinarid deformation front Land Figure 1: Mediterranean Alps LEVANTINE region reconstruction just after the 30°N Marine realm with bathymetric gradation 30°N Elevation (m) 0 20 90 km Messinian Salinity Crisis (Bache et al., Freshwater lake River Apennines 2012), with location of the studied sections in MES BASIN 2000 0 0 the Apennine foredeep. Major tectonic structures Ria A B Studied outcrop 1000 Po Basin Adriatic Sea Ionian Sea 0 1 1 4- Proposed integrated MSC palaeoenvironmental -1000 Pelagosa sill Otranto 2 2 model for the Apennine foredeep sill 1000 C D 3 3 0 -1000 -5000 0 500 km 4 4 -2000

After 5.33 Ma PALAEO-SILL 1000 5 NOSE07 5 0 −10˚-1000 −5˚ 0˚ 5˚ 5- Conclusion10˚ 15˚ 20˚ 25˚ 30˚ The Lago Mare cannot be considered as a uniform brackish palaeoenvironment but must be envisioned as a complex mosaic -2000 0 20 100 km 5.36 - 5.33 Ma of sedimentary facies resulting from competing marine and brackish waters controlled by physiographic factors. N-NW S-SE 1000 0 0 0 The Mesozoic heritage with the Apennine front propagation plays a major role in the palaeo-environmental evolution of the -1000 -2000 Apennine foredeep. Deposits overlying the unconformity separating the regional p-ev1 and p-ev2 formations must hence- 1 1 5.46 - 5.36 Ma forth be regarded as representing the first marine incursion into the isolated central Adriatic Basin after the peak of the 1000 MSC. 2 2 0 -1000 -2000 These results allow us to refine the palaeogeographic reconstruction of the Apennine foredeep during the peak of the MSC. 3 3 5.60 - 5.46 Ma Although this basin was deep, its history during the peak of the MSC did not parallel that of the central Mediterranean basins. 1000 4 diapirTriasic 4 PALAEO-SILL 0 NOSE05 -1000 5 5 -2000 Figure 5: Mediterranean–Adriatic (vs. Apen- 5.60 Ma nine foredeep) connections since 6 Ma: a: loca- 0 20 100 km 260 330 km N-NW S-SE 1000 tion of the cross-sections; b: present-day Figure 4: Line drawings of 0 0 0 cross-section; c: successive reconstructed interpreted seismic profiles in -1000 cross-sections from 5.97 to 5.33 Ma, highligh- the Adriatic Sea showing the -2000 1 1 5.97 - 5.60 Ma ting the role of the Gargano–Pelagosa Messinian Gargano–Pelagosa Mattinata palaeo-sill and Messinian Apennine deforma- palaeo-sill. 2 tectonic 2 Elevation Pelagosa- otranto tion phase. system (m) Gargano sill Apulian Reference 3 3 1000 C palaeo-sill (proj.) D Po Plain Apennine foredeep Anthonissen, D.E., Ogg, J., 2012. Cenozoic and Cretaceous Biochronology of Planktonic Foraminifera and Calcareous Nannofossils. In: Gradstein, F., Ogg, J., Schmitz, M., Ogg, G. (Eds.), The Geological Time Scale 2012. Elsevier, Amsterdam, Appendix escarpment 0 3, pp. 1083–1127. Bache, F., Popescu, S.-M., Rabineau, M., Gorini, C., Suc, J.-P., Clauzon, G., Olivet, J.-L., Rubino, J.-L., Melinte-Dobrinescu, M.C., Estrada, F., Londeix, L., Armijo, R., Meyer, B., Jolivet, L., Jouannic, G., Leroux, E., Aslanian, D., Dos Reis, A.T., Mocochain, Ionian L., Dumurdz anov, N., Zagorchev, I., Lesic , V., Tomic , D., C¸agatay, M.N., Brun, J.-P., Sokoutis, D., Csato, I., Ucarkus, G., C¸akir, Z., 2012. A two-step process for the reflooding of the Mediterranean after the Messinian Salinity Crisis. Basin Research

4 PELAGOSA SILL 4 -1000 24, 125–153. basin Cosentino, D., Buchwaldt, R., Sampalmieri, G., Iadanza, A., Cipollari, P., Schildgen, T.F., Hinnov, L.A., Ramezani, J., Bowring, S.A., 2013. Refining the Mediterranean ‘‘Messinian gap’’ with high-precision U-Pb zircon geochronology, central and northern -2000 Italy. Geology 43, 323–326. Before 5.97 Ma 0 500 km Manzi, V., Gennari, R., Hilgen, F., Krijgsman, W., Lugli, S., Roveri, M., Sierro, F.J., 2013. Age refinement of the Messinian salinity crisis onset in the Mediterranean. Terra Nova 25, 315–322. Milli, S., Moscatelli, M., Stanzione, O., Falcini, F., 2007. Sedimentoligical and physical stratigraphy of the Messinian turbidite deposits of the Laga Basin (central Apennines, Italy). Bollettino della Societa Geologica Italiana 126, 255–281 NOSE02 NOSE01 PENINSULAGARGANO - Popescu, S.-M., Suc, J.-P., Melinte, M., Clauzon, G., Quillevere, F., Suto-Szentai, M., 2007. Earliest Zanclean age for the Colombacci and uppermost Di Tetto formations of the ‘‘latest Messinian’’ northern Apennines: new palaeoenvironmental data from 5 5 Brakish water Hypersaline water Tectonic structures the Maccarone section (Marche Province, Italy). Geobios 40, 359–373. Raffi, I., Backman, J., Fornaciari, E., Pa¨ like, H., Rio, D., Lourens, L., Hilgen, F., 2006. A review of calcareous nannofossil astrobiochronology encompassing the past 25 million years. Quaternary Science Reviews 25, 3113–3137. Messinian Messinian Erosional Roveri, M., Manzi, V., 2006. The Messinian salinity crisis: looking for a new paradigm? Palaeogeography, Palaeoclimatology, Palaeoecology 238, 386–398. Pliocene to Quaternary Oligocene-Miocene Paleogene Mesozoic MES Freshwater Marine water Roveri, M., Manzi, V., Gennari, R., Iaccarino, S.M., Lugli, S., 2008. Recent advancements in the Messinian stratigraphy of Italy and their Mediterranean scale implications. Bollettino della Societa` Paleontologica Italiana 47, 71–85. (ante and syn-MSC) Surface