Sedimentological, geochemical and micropalaeontological data from sediment cores in the northwestern Adriatic Sea were obtained to reconstruct the stratigraphic framework and palaeogeographic setting during the last post-glacial sea-level rise (14000-6000 yr BP). Four lithostratigraphic units were identified: (a) distal plain deposits (>14000 yr BP), submerged during the first phases of marine ingression; (b) coastal lagoon system; (c) barrier-lagoon system, which is dated back to between 10019 +/- 61 and 10228 +/- 174 cal. yr BP from 14 C dating on peat and shell remains; (d) marine prodelta deposits (<5500 yr BP). Geochemical data allow the identification of three distinct sediment sources: River Po, River Adige and Eastern Alpine rivers characterised by decreasing Ni/Mg ratios (50-70, 8-15 and 5-10, respectively) and Ba/Al ratios of 45-55, 55-65 and 35-45, respectively. The three sources display different relative abundances in time. During the Lateglacial, the Po is the main sediment source for the southern cores, whereas the Eastern Alps and the River Adige are the main sediment sources for the northern cores. This suggests a northern position of the Po River bed compared to previous studies. Coastal drowning led to a homogenization of the provenance signal within the sediments. Only after the marine transgression does a River Po signal appear in the northern cores. At the same time, in the southern cores the signal of Eastern Alpine rivers becomes stronger. Transgressive barrier-lagoon and recent sediments do not display a predominant signal for provenance indicators. Copyright (C) 2008 John Wiley & Sons, Ltd.
New insights on late Quaternary palaeogeographic setting in the Northern Adriatic Sea (Italy)
VACCARO, Carmela
2008
Abstract
Sedimentological, geochemical and micropalaeontological data from sediment cores in the northwestern Adriatic Sea were obtained to reconstruct the stratigraphic framework and palaeogeographic setting during the last post-glacial sea-level rise (14000-6000 yr BP). Four lithostratigraphic units were identified: (a) distal plain deposits (>14000 yr BP), submerged during the first phases of marine ingression; (b) coastal lagoon system; (c) barrier-lagoon system, which is dated back to between 10019 +/- 61 and 10228 +/- 174 cal. yr BP from 14 C dating on peat and shell remains; (d) marine prodelta deposits (<5500 yr BP). Geochemical data allow the identification of three distinct sediment sources: River Po, River Adige and Eastern Alpine rivers characterised by decreasing Ni/Mg ratios (50-70, 8-15 and 5-10, respectively) and Ba/Al ratios of 45-55, 55-65 and 35-45, respectively. The three sources display different relative abundances in time. During the Lateglacial, the Po is the main sediment source for the southern cores, whereas the Eastern Alps and the River Adige are the main sediment sources for the northern cores. This suggests a northern position of the Po River bed compared to previous studies. Coastal drowning led to a homogenization of the provenance signal within the sediments. Only after the marine transgression does a River Po signal appear in the northern cores. At the same time, in the southern cores the signal of Eastern Alpine rivers becomes stronger. Transgressive barrier-lagoon and recent sediments do not display a predominant signal for provenance indicators. Copyright (C) 2008 John Wiley & Sons, Ltd.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
