Calcareous plankton biostratigraphy and biochronology of the Pliocene-Lower Pleistocene succession of the Capo Rossello area, Sicily

Detailed correlations of magnetostratigraphy, biostratigraphy and lithostratigraphy reveal that the basal Pliocene is equally complete in the Eraclea Minoa and Capo Rossello sections (Sicily) and the Singa section (Calabria), and that, in accordance with the model of the Pliocene flooding event in the Mediterranean, the deposition of the pelagic marls of the Trubi Formation started synchronously on Sicily and in adjacent Calabria. In addition, the data obtained from the Trubi in the Eraclea Minoa section allows the age of the Miocene-Pliocene boundary to be adjusted slightly from 4.83-4.84 [1] to 4.86 Ma because downward extrapolation of both sedimentation rate and average duration of small-scale sedimentary cycles in the Trubi yields this age for the boundary in this section. Linearly interpolated ages for the top of the Sphaeroidinellopsis acme and the first substantial increase in Globorotalia margaritae (the FOD of this species is non-existent in the Mediterranean Pliocene) at Eraclea Minoa arrive at 4.74 and 4.63 Ma respectively.Because of the detailed magnetostratigraphy and the very accurate dating of the Miocene-Pliocene boundary, it is preferable to select the Eraclea Minoa section as the boundary stratotype rather than the Capo Rossello section.Finally, this age of 4.86 Ma for the Miocene-Pliocene boundary suggests that the beginning of the Pliocene is connected with the termination of a series of latest Miocene glaciations and that the re-establishment of open marine conditions in the Mediterranean might be of glacio-eustatic origin.

Section: Discussionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

The age of the Miocene-Pliocene boundary in the Capo Rossello area (Sicily)

Hilgen

Langereis²

1988

“…This FO corresponds to a first and brief influx followed by a long period of absence. This brief influx of G. truncatulinoides was previously reported from time-equivalent sections elsewhere in the Mediterranean [27] and marks a very distinct bio-event. The reappearance level is not reached in our sections.…”

Section: G Crassaformis Is Regularly But Discontinuouslysupporting

confidence: 72%

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

Zijderveld¹,

Hilgen²,

Langereis³

et al. 1991

118

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.

“…The first occurrence of Ceratolithus acutus 6 m above the base of the Trubi at Capo Rossello [4] provides the only useful criterion for biostratigraphic nannofossil correlation to the open ocean, but unfortunately this marker species is extremely rare in Mediterranean Pliocene sections [45,46]. Like in the open ocean [33], it coincides closely with the lower Thvera reversal boundary.…”

Section: The Desirability Of Redefining the M / P Boundarymentioning

confidence: 99%

“…Like in the open ocean [33], it coincides closely with the lower Thvera reversal boundary. Additional evidence for this synchroneity is provided by the presence of rare Triquetrorhabdulus rugosus in the basal 3-4 m of the Trubi in the Capo Rossello section [46,47]. The use of planktonic foraminifera in distinguishing the M/P boundary biostratigraphically is even more limited.…”

Section: The Desirability Of Redefining the M / P Boundarymentioning

confidence: 99%

A critical re-evaluation of the Miocene/Pliocene boundary as defined in the Mediterranean

Hilgen

Langereis²

1993

A critical re-evaluation of the Miocene/Pliocene (M/P) boundary as defined--informally--in the Mediterranean is presented. We show that ages reported earlier for this boundary (ranging from 4.81 to 4.93 Ma) do not imply any diachroneity of the basal Zanclean lithohorizon which reflects the Pliocene flooding of the Mediterranean and defines the M/P boundary. These ages most likely represent an artefact resulting from intraformational variations in sedimentation rate and inconsistent interpretation of coluor variations in terms of sedimentary cycles. The best estimate for the age of this boundary arrives at 4. Because of its presumably global paleoclimatological significance, the M/P boundary as currently defined in the Mediterranean is preferred to a redefinition of this boundary at the Gilbert/Chron 5 boundary in a continuous open-marine sequence outside the Mediterranean. In addition, this redefinition would lead to unnecessary confusion in global chronostratigraphy.