Magnetostratigraphy-based astronomical tuning of the early Pliocene lacustrine sediments of Ptolemais (NW Greece) and bed-to-bed correlation with the marine record

Abstract

Continental deposits from the early Pliocene lacustrine Ptolemais basin in NW Greece display rhythmical alternations of lignite and marl beds. Three parallel sections from this area are studied using magnetostratigraphy and cyclostratigraphy. The presence of the greater part of the Gilbert Chron enables the recognition of astronomical periodicities in the succession. Especially the precessional influence is evident, as it determines the lithological cycles. The continental Ptolemais composite section is correlated to the most recent astronomical time scale -and thus to the marine reference section: the Rossello composite from Sicily [C.G. Langereis, F.J. Hilgen, The Rossello composite: a Mediterranean and global reference section for the Early to early Late Pliocene, Earth Planet. Sci. Lett. 104 (1991) 211-225] -on a bed-to-bed scale. It is concluded that lignite corresponds to an insolation minimum (beige layer in the Rossello composite), and marl to an insolation maximum (grey layer in the Rossello composite). This implies a precipitation increase during insolation maxima in early Pliocene continental Greece.

Orbital forcing in Pliocene–Pleistocene Mediterranean lacustrine deposits: dominant expression of eccentricity versus precession

“…Recently, many Neogene Mediterranean records from widely different continental environments have been studied: from alluvial to lacustrine (Krijgsman et al, 1997;van Vugt et al, 1998;Steenbrink et al, 1999;Abdul Aziz et al, 2000;van Vugt et al, 2000). In this paper we present the results from one more continental section from southern Romania.…”

“…The section contains some limestone beds of mainly pedogenic origin. van Vugt and Langereis (2000) reported that the thick (,25 m) sedimentary cycles have approximately the same period as precession. So, although the section contains coarse-grained siliciclastic sediment, the dominant period is not eccentricity but precession.…”

“…1 for locations). The ®rst is the lower Pliocene Ptolemais composite section from the elongated intra-montane basin between Kozani and Florina in northern Greece (van Vugt et al, 1998;Steenbrink et al, 1999). The 100 m thick succession consists of a rhythmic alternation of metre-scale lignite and carbonate layers, that can be recognised and correlated across the basin.…”

“…The seven well-de®ned polarity reversals from Ptolemais (Fig. 4, after van Vugt et al, 1998) were used in this way to show that the sedimentary cycles have the same average duration (21.6^0.5 kyr) as the climatic precession cycle (21.7 kyr, ).…”

Eastern Mediterranean foraminiferal palaeoecological response to Mid-Late Pliocene climatic regime: A preliminary note.

“…Numerous studies across the Mediterranean postulate a climatic control on cyclical alternations in marine and terrestrial successions, invoking a linkage with the changeable variations in the Earth's orbital parameters (e.g. Postma & Drinia,1993;Weltje & De Boer, 1993;Kroon et al, 1998;Van Vugt et al, 1998;Wehausen & Brumsack, 1999;Foucault & Mélières 2000;Lourens et al, 2001;Joannin et al, 2007;amongst others). Therefore, it is likely that the sediments of Cyprus should provide a relatively intact archive of past climatic variability, likely to be recognizable on orbital timescales.…”