Dall’Appennino Campano alle Serre Calabre - Cenni palinologici e paleoclimatici

Abstract

Dall’Appennino Campano alle Serre Calabre — Cenni palinologici e paeloclimatici DARIA BERTOLANI MARCHETTI Istituto e Orto Botaizico deZ[’U7zz'verrz'td dz’ Modem: SUMMARY A reconstruction of the vegetational history on palynological basis was performed in the southern italian peninsula in contest of Mediterranean events starting from the Late Miocene (Messinian). Data of this period are not available for the specific area, but palynological studies in perimediterranean lands and deep sea drillings have provided a valid framework. We can thus hypothesize the previously existing vegetational belts and their shift in altitude following climatic impairment occurring in the Late Messinian. - The plio-pleistocene boundary is important and much discussed. It leads to marked glacial events, which follow others ones occurring during the Late Messinian and the Late Pliocene. Interesting sequences are those at Vrica et «Le Castella». The former has been proposed as the stratotype of the Pliocene-Pleistocene transition. Recent researches indicate that the latter is completely of pleistocene age; the basal belt changes from a mediterranean «Macchia-gariga» to a steppe vegetaton, and then perhaps evolves to a light forest of thermophylous hardwoods, with an overhanging coniferous belt. Continental Italy was subjected to the well-known events of alpine glacials during the Pleistocene, whereas the peninsular part should belong to that area of the Mediterranean whose glacial periods are pluvials (Greece, Israel etc.). The presence of mountainous areas along the peninsula and of at least one large lacial center at Gran Sasso induces northern-like conditions. Microtermic elements from Central Europe (Bryop/ayta and P/mzzerop/Jyta) must have migrate in the glacials or stadial along Apennine «cool routes». Absolute dating relative to the Canolo Nuovo (Calabria) diagram places it in the last glacial, late glacial and postglacial. This diagram does not contain evidences of glacials with forest and interglacials with steppic mediterranean conditions but is more closely related to Apennine mountains, having Alpine climatic influences and vegeta- tional features of the forest cycles stated from Chiarugi for the Tuscan Apennines. Similar analogy, with delayed cycles, occurs in the diagrams of Lucania and Abruzzo. Palynological researches has confirmed in the southern part of the peninsula the already known events of Alfie: and Fzzgur, the behaviour of A/mz: irzcazza, and once again the indigenous quality of the Chestnut. INTRODUZIONE Per la ricostruzione delle passate vicende climatico-forestali le ricerche palinologiche, sempre piu affinate, hanno raggiunto un tango di primaria irnportanza. Gli spettri polliruci hanno, come e noto, 1l vantaggio di fornire dati statisticarnente accettabili e riguardanti territori abbastanza ampi e piani altirne- ‘ trici diversi, pur con tutte le difficolta di interpretazione, per la quale si richiede una certa esperienza e una dotazione di conoscenze delle formazioni vegetali anche a livello extraeuropeo. Lo studio delle filliti e di altri macrofossili, che ebbe un grande sviluppo in passato e che tnostra ora recenti sintomi di ripresa, mette molto spesso in evidenza situazioni piu strettamente locali, ecologicamente inquadrate in condi- zioni rnicroclimatiche tendenzialrnente conservative e sottraenti la vegetazione 67