Quaternary subsurface stratigrapby in the Tronto alluvial plain (Marche region, central Italy) was investigated through sedimentological, micropalaeontological (benthic foraminifers, ostracods and calcareous nannofossils) and geochemical analyses of a 60 m long core (TR 1) drilled about 2 km landward from the present shoreline. Elaboration of geochemical data enabled the distinction of sediment provenance (e.g. Tronto River and Adriatic Sea) according to selected geochemical indices. The chronological framework of this succession is mainly based on the analyses of calcareous nannofossils and one AMS ¹⁴C date. In the lower part of the core, outer-shelf deposits showing a homogeneous geochemical composition comparable to present day Adriatic Sea, are replaced upwards by alluvial fan gravels, possibly recording a tectonic event, which produced erosion of the underlying marine sediments. Above the alluvial fan deposits, a coastal plain composed of sediments showing Tronto River provenance and characterized by repeated flooding events, was possibly formed in response to small -scale glacio-eustatic cyclicity. Coastal plain deposits are not well dated, however their low thickness and internal arrangement suggest deposition during minor relative sea-Ievel fluctuations, possibly corresponding to those observed in the initial stage of the last deglacial rise in sea level. Consequently, the overlying shoreface sediments should be attributed to the lower part of the Holocene and the overall regressive tendency observed in the upper part of the core, including delta plain, swamp and alluvial plain deposits, reflects delta and strandplain progradation. The lack of chronological constraints hampers a precise attribution to these deposits; however the AMS ¹⁴C date at 7.95 m core depth confirms the attribution to the Holocene for the upper delta plain deposits. The geochemistry of this part of the core suggests provenance evolution from Tronto River to Adriatic Sea in s
Quaternary subsurface stratigraphy in the Tronto alluvial plain (Italy): palaeoenvironmental evolution and relationships with sediment geochemistry.
Catanzariti R;
2009
Abstract
Quaternary subsurface stratigrapby in the Tronto alluvial plain (Marche region, central Italy) was investigated through sedimentological, micropalaeontological (benthic foraminifers, ostracods and calcareous nannofossils) and geochemical analyses of a 60 m long core (TR 1) drilled about 2 km landward from the present shoreline. Elaboration of geochemical data enabled the distinction of sediment provenance (e.g. Tronto River and Adriatic Sea) according to selected geochemical indices. The chronological framework of this succession is mainly based on the analyses of calcareous nannofossils and one AMS ¹⁴C date. In the lower part of the core, outer-shelf deposits showing a homogeneous geochemical composition comparable to present day Adriatic Sea, are replaced upwards by alluvial fan gravels, possibly recording a tectonic event, which produced erosion of the underlying marine sediments. Above the alluvial fan deposits, a coastal plain composed of sediments showing Tronto River provenance and characterized by repeated flooding events, was possibly formed in response to small -scale glacio-eustatic cyclicity. Coastal plain deposits are not well dated, however their low thickness and internal arrangement suggest deposition during minor relative sea-Ievel fluctuations, possibly corresponding to those observed in the initial stage of the last deglacial rise in sea level. Consequently, the overlying shoreface sediments should be attributed to the lower part of the Holocene and the overall regressive tendency observed in the upper part of the core, including delta plain, swamp and alluvial plain deposits, reflects delta and strandplain progradation. The lack of chronological constraints hampers a precise attribution to these deposits; however the AMS ¹⁴C date at 7.95 m core depth confirms the attribution to the Holocene for the upper delta plain deposits. The geochemistry of this part of the core suggests provenance evolution from Tronto River to Adriatic Sea in sI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
