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Despite the overwhelming control exerted on worldwide coastal evolution by the Lateglacial-early Holocene sea-level rise, high-frequency rapid palaeoenvironmental changes are recorded within a thick postglacial succession buried beneath the southern Po Plain (Northern Italy). Amultidisciplinary study involving sedimentology, micropalaeontology (benthic foraminifers and ostracods), geochemistry (major, minor and trace elements) and radiocarbon dating (14C) on a 40m-long core (240-S5) retrieved inland of the Holocene beach ridges, allowed the reconstruction of articulate coastal scenarios and dynamics - including stages of drainage reorganization. An alluvial plain nourished by the Apenninic Savio River developed in response to low sea-level conditions during the last glacial period. During the first stages of deglaciation (Lateglacial period) the study area was flooded and a coastal plain evolved near the coeval lagoon basin. Subtle change in microfossil content documents the occurrence of a short-term progradational episode that led to the temporary establishment of more terrestrial conditions (likely attributed to the Younger Dryas event - ca. 12,500 cal years BP). Complex and unstable Lateglacial palaeoenvironmental scenarios, and a mixed contribution from two Apenninic rivers (Savio River and Fiumi Uniti system), are suggested by the geochemical composition of coastal sediments. A distinctive flooding event, possibly related to the MWP-1B, caused the abrupt replacement of the coastal plain by a barrier-lagoon system. This landward shift of facies was synchronous with a source area change from the Savio River to the Fiumi Uniti system, triggered by an important phase of drainage system reorganization. Short-term changes in microfossil content also highlight the occurrence of two early Holocene episodes of lagoon infilling not accompanied by significant changes in sediment composition. The complete infilling of lagoon, which evolved in a swamp basin, took place only after ca. 7,600 cal years BP. The establishment of hypohaline environmental conditions is supported by subtle changes in geochemical composition.

Integrating analysis of the benthic palaeoecological record with multivariate ordination techniques represents a powerful synergy able to provide an improved characterization of coastal depositional facies in a sequence stratigraphical perspective. Through quantitative analysis of benthic foraminifer, ostracod and mollusc associations from the postglacial succession of Core M3 (Arno coastal plain, Tuscany, Italy), and application of detrended correspondence analysis (DCA) to the mollusc sub-data set, we offer a refined picture of stratigraphical variations in faunal content from a paralic depositional setting, and reconstruct the palaeoenvironmental gradients that account for such variations. Despite distinct ecological behaviours, and taphonomic and sedimentological constraints, a strong ecological control on meio- and macrofaunal biofacies and taxa turnover is documented across the study succession. Amongst all possible mechanisms that may play a role in ‘shaping’ fossil distribution, the ecological signal driven by salinity represents the most prominent factor controlling the composition of fossil associations in the cored succession. Molluscs can even provide outstanding quantitative estimates of palaeosalinity along the sampled core. When plotted stratigraphically, the three fossil sub-data sets show consistent patterns of vertical evolution that enable prompt identification of the key surfaces for sequence stratigraphical interpretation in otherwise lithologically indistinguishable deposits. The concomitant maximum richness of species with strong marine affinity, paralleled by the highest DCA salinity estimates, allows recognition of the maximum flooding zone, dated to ∼7.7 cal. ka BP, within a homogeneous succession of outer lagoon clays. These clays are sandwiched between early transgressive, swamp to inner lagoon deposits and overlying prograding coastal−alluvial plain facies.

Latest Quaternary coastal deposits are not always exposed on the surface and in such cases can be directly investigated only by means of wells and/or trenches. This report describes how benthic ostracod and mollusk analyses performed on a network of cores enabled a detailed facies characterization of the Late Pleistocene-Holocene successions buried beneath the modern Po Delta and Arno plains (Italy). On the basis of relative abundance categories, key extant mollusk and ostracod taxa commonly retrieved from cored deposits are illustrated and discussed as fundamental facies discriminators. In addition, this report summarizes the major biofacies associations that were formed during the present interglacial in the targeted successions. Some biofacies attributions are straightforward, but others are ambiguous. Where evaluation of individual facies is difficult, the joint consideration of ostracods and mollusks may contribute important information about depositional environments. Finally, thorough the application of detrended correspondence analysis (DCA) to the mollusk part of the dataset, an interpretable paleobiological pattern emerges despite taphonomic and sedimentological overprints. Amongst all possible mechanisms that may play a role in ‘shaping’ macrofossil distribution, the ecological signal driven by salinity represents the most prominent factor controlling the composition of mollusk associations in back-barries environments, whereas water depth appears to be the main driver or the macrofaunal turnover in marine coastal environments. These results support the utility of the stratigraphic paleobiology approach as a fruitful strategy for investigating stratigraphic variations in faunal content from coastal setting and reconstructing the palaeoenvironmental gradients that shape the composition of marine communities.

We present the results of detailed litho-, bio-, and magnetostratigraphic investigations along the Fronte section (Taranto, Italy), where the facies distribution is interpreted using a combined palaeoecological and sequence-stratigraphic approach. The data obtained so far suggest a continuous sedimentary record at the Fronte site, where the MIS 5e peak and subsequent highstand are documented, thus providing robust evidence for the Last Interglacial sedimentary interval.

The 40 m-long core EM2, recovered in the innermost portion of Po delta plain, was sampled for palynological analysis, in order to link coastal-deltaic facies architecture to vegetation dynamics and Holocene climate variability. Pollen data refine facies charac-terization of the 25 m-thick Holocene succession: freshwater swamp clays alternating with overbank/channel sands document millennial to centennial-scale water table oscillations that invariably peak in correspondence of peaty layers. Pollen signature allows identification of the landward equivalent of the Maximum Flooding Surface atop the 7.6 ka-dated peaty interval and furnishes new insights on the relationship between coastal facies patterns and climate events.