Holocene floodplain metamorphosis in the Midlands, United Kingdom

Brown, Antony G.; Keough, M. K.

doi:10.1016/0169-555x(92)90037-o

Cited by 33 publications

(21 citation statements)

References 14 publications

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“…Thus, the discrepancy between ages and pollen biochronology may be explained considering roots penetrating the deep peat from an alder swamp surface settled in situ during the Middle Holocene. Contamination by alder roots is a well-known process in alluvial mires (Brown and Keough, 1992). The uppermost 14 C age, obtained on terrestrial peat, suggests that organic accumulation at Mosi di Crema continued until the Middle Ages, in agreement with written documents (Fino, 1566).…”

supporting

confidence: 54%

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

Ravazzi¹,

Deaddis²,

Amicis³

et al. 2012

geomorphologie

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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. (Marchetti, 1990(Marchetti, , 2002. fig. 10 à fig. 12) fig. 11 et fig. 13A) D'un point de vue méthodologique, on a préparé un DTM détaillé en se servant des points cotés de la Cartographie Technique de la Région Lombardie (fig. 2). La succession stratigraphique a été décrite sur le terrain à partir de plusieurs affleurements et carottes, dont les plus intéressantes ont été soumises aux analyses radiocarbone, palynologiques et minéralogiques (sables). 14 dates AMS ont été obtenues sur plantes terrestres, calibrées avec CALIB à partir de la courbe de calibration IntCal09 (Reimer et al., 2009 ; tab. 2) et indiquées dans le texte « cal. BP ». Certains vestiges archéo-logiques présents dans les dépôts ont été examinés, étant donné qu'ils peuvent fournir des indices chronologiques utiles. L'analyse palynologique s'est faite sur 400 grains. Les plantes aquatiques et de marais ont été exclues de la somme pollinique. Le diagramme pollinique intègre la séquence de tourbes et de tourbes sableuses déposées dans le marais de Mosi di Crema (fig. 9), quelques données polliniques sur échantillons isolés, prélevés dans les dépôts lacustres de Cresmiero, et la séquence fluvio-palustre de Ripalta Guerina (tab. 5). Pour chacun des 13 échantillons de sables étu-diés, 400 points ont été comptés avec la méth...

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supporting

confidence: 54%

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

Ravazzi¹,

Deaddis²,

Amicis³

et al. 2012

geomorphologie

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“…As a result floodplain sedimentation slows down as only larger events will cause overbank flooding. Similar processes in the UK are described by Brown & Keough (1992) as the stablebed aggrading-banks model (SBAB). This may particularly be true for the Geul catchment, as river banks in the Amblève catchment still have a limited height.…”

Section: The Influence Of Environmental Changesmentioning

confidence: 99%

Fluvial architecture of Belgian river systems in contrasting environments: implications for reconstructing the sedimentation history

Notebaert

Houbrechts

Verstraeten

et al. 2011

Netherlands Journal of Geosciences

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Accurate dating is necessary to get insight in the temporal variations in sediment deposition in floodplains. The interpretation of such dates is however dependent on the fluvial architecture of the floodplain. In this study we discuss the fluvial architecture of three contrasting Belgian catchments (Dijle, Geul and Amblève catchment) and how this influences the dating possibilities of net floodplain sediment storage. Although vertical aggradation occurred in all three floodplains during the last part of the Holocene, they differ in the importance of lateral accretion and vertical aggradation during the entire Holocene. Holocene floodplain aggradation is the dominant process in the Dijle catchment. Lateral reworking of the floodplain sediments by river meandering was limited to a part of the floodplain, resulting in stacked point bar deposits. The fluvial architecture allows identifying vertical aggradation without erosional hiatuses. Results show that trends in vertical floodplain aggradation in the Dijle catchment are mainly related to land use changes. In the other two catchments, lateral reworking was the dominant process, and channel lag and point bar deposits occur over the entire floodplain width. Here, tracers were used to date the sediment dynamics: lead from metal mining in the Geul and iron slag from ironworks in the Amblève catchment. These methods allow the identification of two or three discrete periods, but their spatial extent and variations is identified in a continuous way. The fluvial architecture and the limitation in dating with tracers hampered the identification of dominant environmental changes for sediment dynamics in both catchments. Dating methods which provide only discrete point information, like radiocarbon or OSL dating, are best suited for fluvial systems which contain continuous aggradation profiles. Spatially more continuous dating methods, e.g. through the use of tracers, allow to reconstruct past surfaces and allow to reconstruct reworked parts of the floodplain. As such they allow a better reconstruction of past sedimentation rates in systems with important lateral reworking.

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“…De manière assez analogue, dans de nombreuses vallées du Bassin parisien et plus généralement d'europe du nord-Ouest, la sédimentation induite par l'anthropisation apparaît à différentes périodes au cours de l'âge de Bronze (après 2000 cal BC ; Brown & Keough, 1992 ;Pastre et al, 2003 ;Orth et al, 2004), s'est significativement accrue à l'Âge du Fer (Piana et al, 2009 ;Germain-Vallée et Lespez, 2011) ou à la période gallo-romaine (de Moor et al, 2008), puis au Moyen Âge et surtout après (xvi e -xix e siècle) (Antoine, 1997 ;de Moor et al, 2008 ;notebaert et al, 2009 ;Macklin et al, 2010), sans déprise agraire à grande échelle au cours de l'une de ces périodes en particulier (Pastre et al, 1997(Pastre et al, , 2002.…”

Section: Discussion -Conclusionunclassified

Occupation du sol et impact érosif dans la vallée de la Choisille (France, Indre-et-Loire) : approches croisées pour la restitution des paysages anciens

Poirier¹,

Morin²,

Joly³

et al. 2013

archeosciences

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Holocene floodplain metamorphosis in the Midlands, United Kingdom

Cited by 33 publications

References 14 publications

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

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

Fluvial architecture of Belgian river systems in contrasting environments: implications for reconstructing the sedimentation history

Occupation du sol et impact érosif dans la vallée de la Choisille (France, Indre-et-Loire) : approches croisées pour la restitution des paysages anciens

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