Early Holocene transgressive palaeogeography in the Po coastal plain (northern Italy)
| Autor: | Veronica Rossi, Alessandro Amorosi, Daniele Scarponi, Luigi Bruno, Bruno Campo, Wan Hong, Irene Sammartino, Tina M. Drexler, Kevin M. Bohacs |
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| Přispěvatelé: | Bruno, Luigi, Bohacs, Kevin M., Campo, Bruno, Drexler, Tina M., Rossi, Veronica, Sammartino, Irene, Scarponi, Daniele, Hong, Wan, Amorosi, Alessandro |
| Rok vydání: | 2017 |
| Předmět: |
010504 meteorology & atmospheric sciences
Coastal plain Stratigraphy wave-dominated estuary 010502 geochemistry & geophysics 01 natural sciences Early Holocene Paleontology eustatic rise Palaeogeography Geomorphology Holocene 0105 earth and related environmental sciences geography geography.geographical_feature_category local factors Po coastal plain transgressive parasequences Geology Northern italy local factor transgressive parasequence Transgressive |
| Zdroj: | Sedimentology. 64:1792-1816 |
| ISSN: | 0037-0746 |
| DOI: | 10.1111/sed.12374 |
| Popis: | To understand the complex stratigraphic response of a coastal depositional system to rapid eustatic rise and sediment inputs, the evolution of the Adriatic coastline and Po River system, during the post-glacial (Holocene) transgression, was investigated. The landward migration and evolution of a wave-dominated estuary was mapped, based on an extensive data set comprising 14 boreholes, 28 core descriptions and 308 piezocone tests, chronologically constrained between 11·5 and 7·0Âkyr bp by 137 radiocarbon dates. Palaeogeographic maps reveal temporal differences in retrogradational geometries and mechanisms that likely underpin shoreline retreat. The Po estuary initially developed within a shallowly incised valley and then spread onto the interfluves. Between 11·5 and 9·2Âkyr bp the Po fluvial system became avulsive/distributive and wetlands developed in topographically depressed areas. The shoreline retreated at a mean rate of ca 10ÂmÂyearâ1, between 9·2Âkyr and 7·7Âkyr bp, following a stepped trajectory at the centennial scale. After 7·7Âkyr bp, bayhead deltas started to prograde and partially filled the estuary. The overall stratigraphic architecture is interpreted to reflect the sedimentary response of the coastal depositional system to the main pulses of early Holocene eustatic rise. The influence of antecedent topography, partly due to local subsidence, was dominant at the time of initial transgression. Basin morphology influenced sediment dispersal and partitioning. Sediment supplied by the Po River was trapped within the estuary, whereas coastal sand bodies at the estuary mouth were fed by alongshore currents and by reworking of older barriers. High-resolution age control that ties facies evolution to independently constrained eustasy provides direct data to test models of short-term coastal retreat under conditions of relative sea-level rise, and makes this case study a useful analogue for the interpretation of ancient marginal-marine, retrogradational systems where only stratal geometries are available. |
| Databáze: | OpenAIRE |
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