Societe Paleontologic A

Bollettino della SocietePaleontologic a Italiana Pubblicatosotto gli auspici del ConsiglioNazionale delle Ricerche Volume42rr.312003 MIJCCHI MODENA 302 G. IVAPOLEOM et al. 'l-he Faella clay pi, (Albianelli et al., 200L). Moreover, Polarity FaellaSection mosr of in. W fossils are sited in the MS, thus favourila ,h.: presentaim of numerically dating.the classicalfindings of the past rwo centurles stored in the NHMFU Zollectioni by the chronostratigraphy revised by Berggren et al. (1995) and based on the Geomagnetic FJlatiry Time Scale (GPTS). The Pre- sent work intends to illustrate the new magne- setting of the UV sedimentary/ tochronologic . sequence contalnlng ih. late Villafranchian faunal dated ,h: changesof the fossil mag- assemblages, .bt netic vector through its short interval of continuous deposition^ in the MS lacustrineand palustrineseries. The first profile was reconstrucfed in the basal .F( silry sequence(Torre et al., 1993), by_assemblin g a d few short sections as usual for natural exposuresin such soft and flat deposits,but soon aidedby the ones J produced by quarryitg operations for the c\yf € F{ bxploitemeni at-the Maiassiho pit. The besl profile o *is produced for nearly 80 m (Te1t-fig l), by quar- ryinfi the Pratigliolmi clay pit in the Faella territory r.950 (Texl-fig. 2), r{at cuts al.nort the whole MS except a few -eiers on its extremes, and this serieswill be often reported here as the Faellamagnetostratigraph- rc ryPe secilon. This high resolutiondating was alsoapplied to the early Villaflanchian sequence- (Albianelli et al., 1997), and is now being carried out on the Post- I I TheGalleria Tasso Section Villafranchian short- sequence (Albianelli et al., in -I preparation),with the ti- of producing the magne- B tochronoloeic reference for other intramontane sequen.., oT the Apennine basins(Sagri et al., 1994). They could "rr,r-. a new arrangem.nt by correlation *it( the W magnetostratigrapKy,the fiist calibrated ) successionand the one with the earliestterms (Torre et al., 1996). A straight confirmation of thesedates was sequencesoutside the produced by the continental 'West UV. The Lower Valdarno one, from Florence, has yielded rwo short profiles confini.g the lglg sequenceof shallow marine depositsreconstructed by - the magne- Behvenuti et al. (1995), and dated nearly 300 ky i; Text-fig. I View of the sections used to construct-fhe tostratigraphic profile of the MS. A) Faella pi,t the latest Gauss (Albianelli et al., unpublished data), section?uiing the clay quarrving: the lower Part is 35 up to the Montopoli fauna dated 2.58 Ma (Lindsayet m thick, the'upper i8' n',, ih.'t.t'.tlts of the paleo- al., 1980) at the Gauss/Matuyamaboundary. magnetic surveysare also reported by their sideswith A larger interval was recorded in the lacustrine the''Olduvai magnetozones. B) Tlre Galleria Thsso the lining of the railway sequenceof Valtiberina (i" the upper Tiber Valley), section open to construct tunnel, niar the Thssocreek fbr a 32 m thickness. ca. 100 km South from the W. Its continuous basal sequencelasted more than 600 ky, when it was inter- rupt.d by the severetectonics of'the Apennine uplift th"t prod,rced a master fault of the basin and the iilt- calibration can correct the high uncertainty of such a i.g of the claybeds by negly 30". Th.. deposition of dating by adding a high resolutionto it (Napoleone thE sequencetook place during 290 ky in the latest et al..,submitted). Gaussand more than 400 ky until the post-Reunion Matuyama chron, beginning ar 2.14 Ma (,\bbazzi et PREVI ot t HE u P P E R al., 1997; Pontini et al., 2002). Yf*f^[R'L"ttt'Nftr A correlation of recent findines from North of A outline of the UV sequence Rome was done with the UV fauna of late .g:ochronological Villafranchian, basedon the biochronologic point of contarnlngthe vertebratefaunas will be resumed,and view (Mazzini I. et al., 2000); actually, the Present its datesreviewed in order to illustrate the resultsof MAGAIETOCHRONOLOGIC DATING OF L. VILLAFRANCHIAN VERTEBRATECOL, 303 Text-fig. 2 - Topographic setting of the areanear the Faella village, where the reference secnon for the magnetic stratigraphy of the Montevarchi Succession is fixed at the Cava Pratigliolmi-of clay pir. Some the oldest and newest fossil sites are located in its area: Cocchi's collection of 1862 was retrieved at the foot of the Monte al Pero hill close to the Faella creek, while on its top Nestis Rhinoceros was located, while the Poggio Rosso Locdiry of 1995 is the largest fossil assemblage ever collected in the Muse- um record. the magnetochronology applied to the Museum col- sites in Tus cany,although many findings lack the ref- lections,from the oldestones of rwo centuriesago to erenceof a firm topographical or stratigraphicalposi- thoseof April 1999 and January 2000 (Napoleone& tion. Biochronoloeicalaffinities of faunascollected in Azzaroli, 2002). The W fossil collections formed a various sitesof the\orthern Apennines were used for relevant nucleus within the findings which gave ori- dating"fitrt their associations,whose basic characteristics ein to the institution of the Museum, at the end of were described by Pareto ( I 865, in Azzaroli, itr. 17 hundreds (Cioppi, 1999). From the first W 2001). A complete assetof thesecharacters provided catalogue of 356 specimens compiled by Filippo the Villafranchian Stage(Azzaroli, 1977a),which was Nesti in 1845, the fossilsnow consistof nearly 4,000 used for the Italian faunasuntil a new chronological specimens,in a collection harbouring over 20 thou- framework For Mammal Neogene (MN) Ag. sand specimens,which have not yet b"eenfully insert- Classificationof the European faunaswas introduced ed in the automated GEF catalogue(Cioppi et a1.,, (Mein, 1990). 1996). Such a development took place thanks to the For the Villafranchian part, six groups were estab- contribution of gifts by amateur-collectors to the lished in Faunal Units (FU). The tiversa FU is the "Grand Museum sincethe Duke age"of late l7 hun- earliestof the MN 16, later divided into MN l6a and dreds,and to recent recoveriesby the Museum. While MN l6b by Azzaroli, and representsthe base of the the acquisitionsof the last 100 yearsdo not exceed Villafranchian. In the UV the Castelnuovo dei 30o/oof the Museum patrimony, the bulk of the old Sabbioni local fauna is referred to this unit. It collectionsformed the basefor the ordination of the includes fossils from the old lignite mines and clay W faunas in the biochronological system (Azzaroli et quarries(among which are thoseof Gaville,Tegolaio, al., 1992). Then, the biostratigraphical correlation Montetermini, and the large one at Santa Barbara), was attempted in order to integrate a regional classi- on the left bank of the Arno river. The next middle fication of the European faunas in the chronostrati- Villafranchian is formed by Montopoli FU from the graphic system,and finally magnetic stratigraphy has Lower Valdarno (the unit MNl6b), Saint Vallier FU provided the geochronology of the sedimentary from Franceand Costa San Giacomo FU in central sequencesand of their fossil content by assigning Italy, which are not representedin the UV. Then, the them a numerical ase. Olivola FU from northern Tuscany (.t. 100 km These stepsin Jating the UV history emphasize North from the UV) marked the onset of the late the role played by the MNHFU collectionsof verte- Villafranchian and is first representedin the UV by bratesin focusingthe studieson the basin evolution. the Matassino fauna, in the clay pit near Figline (Text-fig. 2). It may be pointed out that the age of n) BTocHRoNoLoGICALsuccESSIoN oF FAUNAS this fauna was initially equatedto that of the Olivola FU and then assumed shortly younger (Azzaroli, Chronoloeical classificationof faunasin the intra- 1983). Most significant,in fact, was seenin the UV monrane PliolPleistocenebasins and littoral deposits the association-of Equus stenonisand E. stehlini all of the Apennines and lowlands receiveda fundamen- through the MS, while the latter speciesis lacking at tal contribution from the UV collectionsand other Olivola (Azzaroli, 1950), and other speciesof Olivola 304 G. MPOLEONE etal. were present at St. Vallier and not in the UV. The netic vector, which is worldwide acti.g for each time Villafianchian ageends in the W with the ThssoFU, interval during a geomagneticepoch and successively collected in the irea of the Thssovillage, and contin- changes, thus- mlkittg ihe polariry,.,sequel... This ues in the Italian peninsula with the Farneta FU and sequencerepresents the continuous flow of the geo- Pirro FU, as lately reviewedby Azzaroli (2001)- logi. time -."r,,rred in years, since the record of'the manne magnetlc anomalies and each one of its B) BrosrnertcRAPHICALRESoLUTIoN changet ptoluced a polariry event defined within few tho,ri"ttd y."rs. Therefore, the UV faunas calibrated The need to insert the FU from continental to such a- time scale were recently correlated with sequences into chronostratigraphy had always those from India (rMzaroh et al., 1997), since the lat- oro-pted studiesto searchcommon elementsto link ter had also been calibrated by magnetic stratigrlptry biochronological and biostratigraphical classifica- (Azzaroli 6{ Napoleone, I 981). Calibration of the tions. The iilfluence exerted bi Gignoux since the W faunal associations(Torre et Al., 1993; Albianelli early 19 hundreds was fundam.ttt"f itt finding ,lt. et dl., 1995; 1997; 2002) correlates the early besi Italian Plio-Pleistocene sites for fixing the Villafranchian fauna of the tiversa FU with the Thtrot stage in the Himal ayan sequences,while the Neogene stratorype_s.In contrast, more recent ry:ly- ^ seswere partial and scanry (Azzaroli & Berzi, 1970; late Villifranchian containing the faunas of Ambroseiti et al., 1972; Azzaroli, 1977a;1983; Torre, Matassino, Faella, Poggio Rosso, Casa Frata, and 1987). In former years, the onset of the late Tasso is correlated i"-ith the Pinjor.

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