The last 40 ka evolution of the Central Po Plain between the Adda and Serio rivers

We reconstructed the geological evolution and the history of the fluvial network in the central part of the Po Plain in Lombardy, northern Italy, since the Middle Würm. We focused on evidences of dissection and incision of former rivers into the large outwash fans originating from piedmont glaciers of the southern Alps in the Last Glacial Maximum. The studied area is located between the Po River and the Alps north of the Adda/Serio river confluence, around the town of Crema. Morphometric analysis and stratigraphic investigation were carried out, supported by palaeobotany, sand petrography and radiometric dating. The obtained stratigraphic framework is presented by cross sections and by a geological map. During the Middle Würm, an alluvial fan of the Adda River oriented NWN-SSE occupied the area, feeding south and west the Romanengo hill. A substantial reorganisation of the fluvial network occurred during the Last Glacial Maximum. Since 32-30 ka cal. BP, the area was fed by two outwash rivers, originated from the Adda and the Oglio piedmont glaciers, both characterised by a prevalent southward drainage, 160°-170° S in the LGM. After the LGM the fan-head was dissected by trunk channels and, at the downslope fan limit, the southward flow shifted to a southeastern direction. Thereafter, major dissection and downcutting occurred in the Lateglacial, confining the major rivers into large alluvial corridors, further shaped by lateral erosion during the Holocene. The Late Holocene history of the Serio River is marked by fluvial floods during the late Roman Age, and by a capture of the lower reach by the Adda River. The geomorphological evidence supports the historically inferred age assignment of the diversion to 12th-14th c. AD.L’évolution géologique et l’histoire du réseau fluvial dans la partie centrale de la plaine du Pô en Lombardie ont été reconstituées à partir du Würm moyen. Le territoire environnant la ville de Crema entre les rivières Adda et Serio est caractérisé par des paléovallées encaissées dans de grands cônes en lien avec les glaciers du piémont méridional des Alpes pendant la dernière glaciation. L’étude morphométrique et stratigraphique a été supportée par les analyses paléobotaniques, pétrographiques sur sables et galets et par plusieurs déterminations radiométriques. Au Würm moyen, un cône alluvial mis en place par la rivière Adda s’orientait NWN-SSE et occupait la région étudiée, s’appuyant sur la colline de Romanengo au sud et à l’ouest. A partir de 32-30 ka cal. BP [i.e., au début du Dernier Maximum Glaciaire (DMG)], une réorganisation importante du réseau hydrographique (orientation nettement sud) est forcée par le développement de deux sandurs des domaines glaciaires de l’Adda et de l’Oglio. Le sommet des cônes est creusé par les paléochenaux post-DMG, lorsque, à la base des cônes, la direction des paléochenaux, qui était 160-170° pendant la dernière phase d’aggradation, devient sud-ouest. Ce nouveau système de drainage est fossilisé par une phase d’incision importante au Tardiglaciaire, avant que les rivières soient confinées dans des corridors alluviaux et sujets à l’érosion latérale au cours de l’Holocène. L’histoire de la rivière Serio est marquée par des phénomènes d’alluvionnement au cours de l’Antiquité tardive puis par la capture de son cours inférieur par la rivière Adda. Les preuves géomorphologiques concordent avec les sources écrites, suggérant que le changement de tracé se produit entre le XIIe s. et le XIVe s. apr. J.-C

Lake evolution and landscape history in the lower Mincio River valley, unravelling drainage changes in the central Po Plain (N-Italy) since the Bronze Age

The Etruscan harbour of Forcello in lower valley of the Mincio River, N-Italy, was active between 540 and 390 yr BC. The stratigraphic investigations revealed that the settlement occupied a hill on the shore of a large lake. The lake sediments and the palaeoecological record, supported by radiocarbon ages, documented the basin origin in the Middle Bronze Age as well as the development of aquatic and terrestrial vegetation trhough the Iron Age and the Roman age, until the Late Middle Age reclamation. The lake expanded during the early Iron Age, after the diversion of the Po River at Guastalla. The bed-load and sedimentation rates in the Po river system has been related to the lake development through damming at the confluence with the Mincio River. This circumstance allowed a new assessment of the Late Holocene palaeodrainage changes in the Central Po Plain. Subsidence related to local tectonics in the axial portion of the river network is a triggering factor, coupled with an increase of bed-load discharge. The latter resulted from a complex response to rising base-level of the Po Plain fluvial system, induced by increasing sea level. Bronze Age human pressure on forest may also have contributed to this bed-load increase

Scenari di ricostruzione delle interazioni uomo-ambiente-clima in Lombardia (N-Italia) dal Paleolitico medio all’età del Ferro

This contribution aims to provide an updated and concise overview of the main events and developments characterising the interaction between human communities and their environment in Lombardy (Northern Italy) between the Middle Paleolithic and the Late Iron Age (60,000 to 2,100 years cal BP). Within the above defined geographic and chronological context, our main goal is to highlight and summarise the role of natural factors in the development of human history, both over the long durée and within defined periods. We provide a short history of the ecosystems and socio-ecological systems in Lombardy, for which – thanks to the contribution of several research groups and scholars active in the region – we analyse specific key issues. These analyses are facilitated by chronostratigraphic tables and GIS-based cartography, and introduced by an overview of the climatic changes that affected Alpine and Po Plain landscapes across the Last Glaciation and subsequent Late Glacial times, up to the shortlasting events which influenced the development of Holocene civilisations. The structure and significance of the issues introduced in the overview will be discussed by individual research groups working within this study are

Characterising key issues in human–environment interactions in Lombardy (N-Italy) from the Middle Paleolithic to the Iron Age

This contribution aims to provide an updated and concise overview of the main events and developments characterising the interaction between human communities and their environment in Lombardy (Northern Italy) between the Middle Paleolithic and the Late Iron Age (60,000 to 2,100 years cal BP). Within the above defined geographic and chronological context, our main goal is to highlight and summarise the role of natural factors in the development of human history, both over the long durée and within defined periods. We provide a short history of the ecosystems and socio-ecological systems in Lombardy, for which – thanks to the contribution of several research groups and scholars active in the region – we analyse specific key issues. These analyses are facilitated by chronostratigraphic tables and GIS-based cartography, and introduced by an overview of the climatic changes that affected Alpine and Po Plain landscapes across the Last Glaciation and subsequent Late Glacial times, up to the shortlasting events which influenced the development of Holocene civilisations. The structure and significance of the issues introduced in the overview will be discussed by individual research groups working within this study are