Sedimentology, faunal content and pollen record of Middle Pleistocene palustrine and lagoonal sediments from the Peri-Adriatic basin, Abruzzi, eastern central Italy

Abstract

A 25 m-thick outcrop section exposed at Torre Mucchia, on the sea-cliff north of Ortona, eastern central Italy, comprises a rare Middle Pleistocene succession of shallow-water and paralic sediments along the western Adriatic Sea. An integrated study of the section, including facies and microfacies analyses, and characterization of paleobiological associations (mollusks, fishes, ostracods, foraminifers and pollen), enable a detailed reconstruction of the paleoenvironmental and paleoclimatic conditions during deposition. The shallow-water deposits include a transgressive, deepening- and fining-upward shoreface to offshore-transition facies succession overlain by a regressive shoreface-foreshore sandstone body with an erosive base and a rooted and pedogenically altered horizon at the top that imply deposition during sea-level fall. This forced regressive unit is overlain by paralic strata forming a transgressive succession comprising palustrine carbonates and back-barrier lagoonal mudstones. The palustrine carbonates exhibit some of the typical features encountered in palustrine limestones deposited within seasonal freshwater wetlands (marl prairies). Following the sea-level rising trend, the freshwater marshes were abruptly replaced by a barrier-lagoon system that allowed deposition of the overlying mud-rich unit. Within these deposits, the faunal assemblages are consistent with a low-energy brackish environment characterized by a relatively high degree of confinement. The pollen record documents the development of open forest vegetation dominated by Pinus and accompanied by a number of mesophilous and thermophilous tree taxa, whose composition supports a tentative correlation with Marine Oxygen Isotope Stage 17. The new pollen record from Torre Mucchia improves our understanding of the vegetation development in the Italian Peninsula during the Middle Pleistocene and sheds new light on the role played by the most marked glacial periods in determining the history of tree taxa

Quaternary disappearance of tree taxa from Southern Europe: Timing and trends

“…However, macrofossil finds are reported at the site of Oriolo dated around 800 ka (Martinetto and Sami, 2001). In Central Italy, Tsuga was still found with percentages >3% in an early interglacial phase correlated with MIS 17 (Pieruccini et al, 2016) , 1994). However, it was virtually absent from some sites (Lebreton, 2002), suggesting that its distribution was rather patchy.…”

“…Sparse pollen grains of Taxodium type are still found in the Calabrian records. In the early Middle Pleistocene, the Torre Mucchia record, correlated with MIS (Pieruccini et al, 2016), displays the last significant abundance (>3%) of Tsuga and Carya, which are recorded for the last time during interglacial periods corresponding to MIS 13 (Sessano: Russo Ermolli et al, 2010a and MIS 9 (Boiano: Orain et al, 2013;Russo Ermolli et al, 2015), respectively. The last occurrence of Pterocarya, still very abundant in both the pollen and macrofossil records from Riano (Follieri, 1958(Follieri, , 1962, likely correlated to MIS 11, is recorded at Valle di Castiglione around 200 ka (Follieri et al, 1988).…”

“…to the temperate Holsteinian interglacial, corresponding to Marine Isotope Stage (MIS) 11, on the basis of the occurrence of Pterocarya and the dominance of Abies (Field et al, 2000), according to the records of the Velay maar in the French Massif (Reille et al, 2000). Similarly, the record from Torre Mucchia (Central Italy) has been correlated to MIS 17 on the basis of the underlying Bruhnes/Matuyama magnetostratigraphic boundary coupled with a significant abundance of Tsuga (Pieruccini at al., 2016), which is only sporadically found in Central and Southern Italy after MIS 16 (Russo Ermolli et al, 2015). On the other hand, this approach may be rather weak and may lead to misleading interpretations.…”

The MIS 13 interglacial at Ceprano, Italy, in the context of Middle Pleistocene vegetation changes in southern Europe

“…In central Italy it is represented with values around 5% during MIS 17 (Pieruccini et al, 2016). Then it is still frequently found during interglacial phases correlated with MIS 15 and 13 (Russo Ermolli, 1994; Russo Ermolli et al, 2010), after which it progressively declines and is last recorded during MIS 9 at Boiano (Orain et al, 2013).…”

“…Ravazzi, 2003;Fusco, 2007;Ravazzi et al, 2005;Joannin et al, 2007), but it disappeared from northern Italy in the late Early Pleistocene (MIS 22;Muttoni et al, 2003). In Central Italy, Tsuga is still present at >3% during MIS 17 at Torre Mucchia (Pieruccini et al, 2016) while only single pollen grains are recorded at Sessano during MIS 13 (Russo Ermolli et al, 2010). Nevertheless, its virtual absence from any other site of this age (Russo Ermolli, 1994;Lebreton, 2002) suggests that its distribution was rather patchy (Magri et al, 2017).…”