Maurizio Cucato’s scientific contributions

Notes to the Sheet 009-ANTERSELVA of the 1:50.000 Geological Map of Italy

To link to this article: https://www.tandfonline.com/doi/full/10.1080/17445647.2018.1531074 A 1:50,000-scale geomorphological map of the Adige/Etsch River valley bottom (NE Italy) is presented. The study area is 115 km long, and it extends between the villages of Merano/ Meran and Calliano, including also the terminal segments of 9 major tributaries of the Adige River. Presently, the Adige shows a sinuous to straight morphology owing to massive channelization occurred during the nineteenth century. Fluvial geomorphological features have been mapped through a detailed-scale comparative multi-temporal analysis carried out on several historical maps dating since the eighteenth century, previous thematic maps, geological maps of the Italian ‘CARG’ project, orthophotos (2011) and high – resolution DEMs. The map shows the active river channel, dating to 1803–1805 (before channelization), to 1856-1861 (during channelization) and under present conditions, as well as several paleochannels dating up to the thirteenth century. The analysis led to define the corridor of historical channel changes, a fundamental tool for river management purposes.

A 1:50,000-scale geomorphological map of the Adige/Etsch River valley bottom (NE Italy) is presented. The study area is 115 km long, and it extends between the city of Merano/Meran and the village of Calliano, including also the terminal segments of 9 major tributaries of the Adige River. Presently, the Adige shows a sinuous to straight morphology owing to massive channelization occurred during the 19th century. Fluvial geomorphological features have been mapped through a detailed-scale comparative multi-temporal analysis carried out on several historical maps dating since the 18th century, previous thematic maps, geological maps of the Italian “CARG” project, orthophotos (2011) and high – resolution DEM. The map shows the active river channel, including bars and islands, dating to 1803-1805 (before channelization), to 1856-1861 (during channelization works) and under present conditions, as well as several paleo-channels dating up to the 13th century. The analysis led to define the corridor of historical channel changes, a fundamental tool for river management purposes (ecological restoration and flood hazard mitigation).

We reconstruct the post−Last Glacial Maximum (LGM) evolution of the upper Adige River floodplain, Eastern Italian Alps. In particular, we are interested in constraining the time scales associated with fan building and understanding how the relevant sediment supply at tributary confluences has interacted with the Adige River to form the present landscape configuration. By combining high-resolution seismic imaging with drillhole data and radiocarbon dating, we show (i) that ∼80% of the valley fill was deposited in post-LGM times, (ii) that sediment evacuation from tributaries began with local deglaciation at the end of the Younger Dryas; and (iii) that tributary basin aspect and size, by controlling the local pattern of deglaciation, may have delayed fan building by up to two millennia. Debris-flow sediment supply from the Gadria-Strimm system drove the evolution of this valley segment between 12 and 6.25 k.y. B.P., first deflecting, then damming the course of the Adige River, forming a lake, and affecting the shape and size of the neighboring fans. Our data show an anisotropic development of the Gadria fan, with growth focused on the central and eastern portion of the fan between 10 and 8.5 k.y. B.P., followed by gradual lateral shifting toward west for about the next two millennia. The estimated sediment yield associated with the fan formation describes a debris flow−driven paraglacial sedimentary wave that conforms to the conceptual model originally proposed by Church and Ryder (1972), but never tested before in upland basins with empirical data. The wave lasted for ∼4 k.y. and around 9 k.y. B.P. peaked at ∼390,000 m3yr−1. At the valley profile scale, results suggest that similar fans functioned as effective sediment traps, which prevented, and still limit, fluvial reworking and valley floor incision. We argue that these geomorphic barriers, which have enhanced fragmentation of the valley long profile, with knickpoints located at major tributary fans, have delayed postglacial landscape recovery until today. https://doi.org/10.1130/B31924.1

a b s t r a c t This work concerns the Late Quaternary evolution of the Astico Valley, with a focus on the relations between the glacial complexes hosted in the terminal valley tract and the piedmont fans. Three distinct glacial events are considered in this paper. Remote sensing, field survey, stratigraphic measurements and reconstructions, sand petrography, radiocarbon dating and pollen analyses allowed attribution of the last one to the LGM, a previous one probably to MIS 6 and the oldest to a generic glaciation of the Middle Pleistocene. Sand petrography analyses show that all these glacial deposits contain rock fragments that reached the Astico Valley through a transfluence of the Adige glacier. During LGM, this glacial stream entered the Astico Valley from the north through the Carbonare saddle (1075 m a.s.l.), as probably happened in previous major glaciations. The chronostratigraphy of two cores drilled near the towns of Vicenza and Villaverla shows that the outwash stream changed its route to the piedmont plain at the end of LGM, as a response to rapid glacial collapse. This switch led to the deactivation of the northwestern sector of the plain (Thiene fan) in favour of the southeastern one (Sandrigo fan). The lower and middle Astico Valley preserved significant evidence of even minor glacial fluctuations during the LGM in response to subtle climatic changes, namely an early glacial withdrawal at 23e24 cal ka, which may be difficult to distinguish in major Alpine glaciers.