Integrated magnetostratigraphy and biostratigraphy of the upper Pliocene-lower Pleistocene from the Monte Singa and Crotone areas in Calabria, Italy

Abstract

The results of a detailed magnetostratigraphic and biostratigraphic study of late Pliocene to early Pleistocene marine marl sequences from the Monte Singa and Crotone areas in Calabria, Italy are presented.The magnetostratigraphy from the Monte Singa sequence ranges from below the Gauss/Matuyama boundary up to and including the lower Olduvai boundary. Normal polarities at a level corresponding to isotope stage 81 most probably represent the R~union subchron. From the lower Olduvai boundary upward, a reliable magnetostratigraphy could not be established due to increased weathering of the marls, resulting in mainly secondary magnetizations.The magnetostratigraphy from the composite sequence of the Crotone area belongs to a large part of the Matuyama Chron and includes the Olduvai subchron. The position of the lower and upper boundaries of the Olduvai subzone could be established more precisely than from earlier results. Moreover, the upper boundary of the Olduvai subzone poses an ambiguity: a relatively long normal polarity interval representing the main Olduvai subchron and corresponding to a duration of 115 ka is followed by a short (30 ka) reversed subchron and the short (15 ka) normal Vrica subchron. Another option, and more in accordance with the duration of the Olduvai subchron in literature, would be to consider the complete N-R-N polarity succession with a total duration of 160 ka as representing the Olduvai subchron, implying that this Olduvai subchron has a short reversed interval in its upper part.Linear interpolation and extrapolation yield ages for the most important late Pliocene-early Pleistocene biostratigraphic datum levels. An age of 1.69 Ma is found for the Pliocene-Pleistocene boundary, using the conventional polarity time scale dated with radiometric results. However Hilgen [1], in correlating the sapropel groups and patterns to the precession curve of the Earth's orbit, obtained significantly different ages for the polarity transitions of the present study. According to this astronomically calibrated polarity time scale, the age of the Pliocene-Pleistocene boundary is 1.81 Ma.

Calcareous nannofossils in the basal Zanclean of the Eastern Mediterranean Sea: remarks on paleoceanography and sapropel formation

“…Concerning the latter, the problem of the selection of an appropriate Global Standard Stratotype-section and Point (GSSP) of the Zanclean Stage strongly depends upon the demonstration of the absence of a significant hiatus across the Messinian/Zanclean boundary. This boundary was formally proposed in the Capo Rossello section by Cita (1975a) and subsequently proved to correlate with the fifth precession-related astronomical cycle below the Thvera magnetic event (Zijderveld et al, 1991;Hilgen, 1991b;Hilgen and Langereis, 1993). From a biostratigraphic point of view, the Messinian/Zanclean boundary is usually regarded as poorly constrained in the Mediterranean area, because of the basically nonmarine nature of the upper Messinian sediments (e.g., Arenazzolo Formation in Sicily) and of the lack of globally recognized nannofossil and foraminiferal bioevents in the very basal Zanclean.…”

Sequence stratigraphy of the Nukumaruan Stratotype (Pliocene‐Pleistocene, c. 2.08–1.63 Ma), Wanganui Basin, New Zealand

“…Using the Ototoka tephra tie-point, coastal sequences NC1-NC11 correspond to basin sequences 12-21 of the composite record and were deposited during OIS 77-57. The correlations allow the Pliocene-Pleistocene boundary (Zijderveld et al 1991 ;Lourens et al 1996) to be placed at the base of the Lower Maxwell Formation, at the top of the transgressive part of sequence NC7 (Fig. 3, 16).…”

Late Pliocene climate variability on Milankovitch to millennial time scales: A high-resolution study of MIS100 from the Mediterranean

“…Evidence for occasional massive discharge of icebergs during these first full glacial cycles comes from ice rafted debris (IRD) records in DSDP/ODP cores from the North Atlantic Carter and Raymo, 1999). Rapid changes in the size of the continental ice-sheets at that time are confirmed by major shifts in benthic Verhallen, 1987;Zijderveld et al, 1991) are labelled in the photograph of SN. Thick black and grey bars at the right hand side of the photograph indicate stratigraphic positions (scale bar lower right corner) of sapropels as recorded by and thin bars indicate positions of sapropels as assumed from the photograph.…”