scholarly journals Late Holocene channel pattern change from laterally stable to meandering – a palaeohydrological reconstruction

2018 ◽  
Vol 6 (3) ◽  
pp. 723-741 ◽  
Author(s):  
Jasper H. J. Candel ◽  
Maarten G. Kleinhans ◽  
Bart Makaske ◽  
Wim Z. Hoek ◽  
Cindy Quik ◽  
...  
Keyword(s):  
Middle Ages ◽  
Late Holocene ◽  
Low Energy ◽  
Osl Dating ◽  
Meandering Rivers ◽  
Channel Pattern ◽  
The Holocene ◽  
Late Middle Ages ◽  
Bankfull Discharge ◽  
Pattern Change

Abstract. River channel patterns may alter due to changes in hydrological regime related to changes in climate and/or land cover. Such changes are well documented for transitions between meandering and braiding rivers, whereas channel pattern changes between laterally stable and meandering rivers are poorly documented and understood. We hypothesize that many low-energy meandering rivers had relatively low peak discharges and were laterally stable during most of the Holocene, when climate was relatively stable and human impact was limited. Our objectives in this work are to identify a Late Holocene channel pattern change for the low-energy Overijsselse Vecht river, to develop and apply a novel methodology to reconstruct discharge as a function of time following a stochastic approach, and to relate this channel pattern change to reconstructed hydrological changes. We established that the Overijsselse Vecht was laterally virtually stable throughout the Holocene until the Late Middle Ages, after which large meanders formed at lateral migration rates of about 2 m yr−1. The lateral stability before the Late Middle Ages was constrained using a combination of coring information, ground-penetrating radar (GPR), radiocarbon (14C) dating, and optically stimulated luminescence (OSL) dating. We quantified bankfull palaeodischarge as a function of time based on channel dimensions that were reconstructed from the scroll bar sequence and channel cut-offs using coring information and GPR data, combined with chronological constraints from historical maps and OSL dating. We found that the bankfull discharge was significantly greater during the meandering phase compared to the laterally stable phase. Empirical channel and bar pattern models showed that this increase can explain the channel pattern change. The bankfull discharge increase likely reflects climate changes related to the Little Ice Age and/or land use changes in the catchment, in particular as a result of peat reclamation and exploitation.

scholarly journals Late Holocene channel pattern change from laterally stable to meandering caused by climate and land use changes

2018 ◽  
Author(s):  
Jasper H. J. Candel ◽  
Maarten G. Kleinhans ◽  
Bart Makaske ◽  
Wim Z. Hoek ◽  
Cindy Quik ◽  
...  
Keyword(s):  
Land Use ◽  
Middle Ages ◽  
Land Use Changes ◽  
River Channel ◽  
Osl Dating ◽  
Meandering Rivers ◽  
Channel Pattern ◽  
The Holocene ◽  
Late Middle Ages ◽  
Bankfull Discharge

Abstract. River channel patterns may alter due to changes in hydrological regime, related to changes in climate or land cover. Such changes are well documented for transitions between meandering and braiding rivers, whereas channel pattern changes between laterally stable and meandering rivers are poorly documented and understood. We identified a river that was laterally almost stable throughout the Holocene until the Late Middle Ages, after which large meanders formed at lateral migration rates of about 2 m yr−1. The lateral stability before the Late Middle Ages was proven using a combination of coring information, ground-penetrating radar (GPR), radiocarbon (14C) dating, and optically stimulated luminescence (OSL) dating. Our objective of this work is to identify the possible causes for the meander initiation. We carried out a unique reconstruction of bankfull discharge as a function of time, based on channel dimensions that were reconstructed from the scroll bar sequence using coring information and GPR data, combined with chronological constraints from historical maps and OSL dating. Empirical channel and bar pattern models were used to determine the potential for meandering and to identify the causes of meander initiation. Several potential causes were investigated, varying from discharge regime changes to increased sediment input. Our investigation shows that bankfull discharge was two to five times higher during the meandering phase compared to the laterally stable phase. This increase likely reflects climate changes related to the Little Ice Age and land use changes in the catchment, in particular as a result of peat reclamation and exploitation. We hypothesize that many low-energy meandering rivers were laterally stable during most of the Holocene, reflecting relatively low peak discharges during a stable climate and with limited human impact. However, channel deposits associated with such stable phases are poorly preserved, due to recent increase in dynamics of such systems. Considering the importance of climate and land use changes on the river channel pattern, successful river restoration requires an integral approach that includes scenarios of climate and land use changes in the catchment.

scholarly journals Disturbances Of The Holocene Lake-Bog Sediment Succession As Revealed By Pollen Record From Wietrzychowice (Southeastern Kujawy, Central Poland)

2015 ◽  
Vol 32 (2) ◽  
pp. 91-97
Author(s):  
Eva Břízová ◽  
Małgorzata Roman
Keyword(s):  
Middle Ages ◽  
Pollen Analysis ◽  
Pollen Record ◽  
Sediment Characteristics ◽  
Pollen Data ◽  
The Holocene ◽  
The Third ◽  
Late Middle Ages ◽  
Organic Sediments ◽  
Funnel Beaker Culture

Abstract Results of geological and pollen investigations of the lake-bog sediments from the section Wietrzychowice W5, located nearby the Neolithic Funnel Beaker Culture (FBC) megaliths, are presented. The pollen data reveal that sedimentation at Wietrzychowice has begun at the beginning of the Holocene (Preboreal). Pollen analysis was used to determine stratigraphy with regard to sediment characteristics. The pollen spectrum was divided into 8 LPAZes (1-7Xa, 7Xb) which were also, where possible, stratigraphically classified. Radiocarbon dating of 6 730 ± 90 BP (5 730–5 480 BC, MKL-702) at depth of 1.20 m confirmed the pollen analysis age estimation. Five settlement episodes were found in organic sediments in the upper part of the W5 core. The first was presumably during the Preboreal, the second in the early Atlantic, the third in the late Atlantic (probably Neolithic FBC), the fourth in the early Middle Ages and the last one in the late Middle Ages. The pollen analysis was useful to point irregularities in sediment succession. Such a situation made palaeoenvironmental interpretation difficult, but further research is still needed to enable an accurate reconstruction.

scholarly journals Maximum Holocene groundwater levels and associated extension of peat in the border zone of ‘Het Gooi’ (the Netherlands): a reconstruction based on the study of soil transects

2020 ◽  
Vol 99 ◽  
Author(s):  
Jan Sevink ◽  
Sander Koopman
Keyword(s):  
Hydraulic Conductivity ◽  
Sea Level ◽  
Middle Ages ◽  
Groundwater Level ◽  
Soil Characteristics ◽  
Border Zone ◽  
Maximum Extension ◽  
The Holocene ◽  
Late Middle Ages ◽  
Ridge System

Abstract The area ‘Het Gooi’ in the Netherlands is part of a Pleistocene ice-pushed ridge system that partially drowned during the Holocene upon sea level and associated groundwater rise. As a result, the ridge system was gradually encroached by peat. From the late Middle Ages onward, man reclaimed the peatlands surrounding Het Gooi, heavily reducing their extension and lowering the regional groundwater level by increasingly intensive drainage. Based on historical and archaeological arguments, several authors assume that the Holocene peat cover in the border zones of ‘Het Gooi’ formed the extension of large raised peat bogs that formed further to the west and east, respectively. They presume that in the late Middle Ages these extensions reached ‘upslope’ to a maximum altitude of 3 m + NAP (Dutch Ordnance Datum – approximating mean sea level). However, the original extension is difficult to reconstruct, as this peat has disappeared as a result of its exploitation and oxidation, if having been present at all. In this study, the maximum extension of the Holocene peat cover on the ice-pushed ridge system was reconstructed based on soil characteristics. Used soil characteristics concerned the presence of iron coatings around sand grains and the upper boundary of gleyic features, because these are indicators for the mean highest groundwater level (MHG). For peat to form, this MHG needs to be at or just above the ground surface for most of the year. Based on study of a number of soil transects, we reconstructed to what maximum altitude peat encroachment may have occurred. This ‘maximum extension’ can alternatively be described as the maximum altitude of the bottom of the peat onlapping the ridge system. In the western border zone, this peat cover was found to have reached to c. NAP or just above, near Hilversum. No indications were found for the occurrence of raised bogs. We conclude that the phreatic groundwater level in this zone was controlled by the sea level and associated lake levels (Naardermeer and Horstermeer), a dominant role being played by the shallow presence of Pleistocene formations with a high hydraulic conductivity. In the eastern border zone, altitudes were more variable and in places reached 2 m + NAP. Peat at this higher elevation probably formed under the influence of a higher phreatic groundwater level, induced by the presence of a clayey Eemian fill with low hydraulic conductivity in the adjacent glacial basin (the Eem valley). This study demonstrates the value of detailed soil transect studies for palaeogeographical reconstructions of the former Holocene peat cover in Pleistocene landscapes of NW Europe. It also provides independent data for validation of geohydrological models for such landscapes.

scholarly journals Zur jungholozänen Oberflächen- und Bodenentwicklung der Siegaue im Hennefer Mäanderbogen

1996 ◽  
Vol 46 (1) ◽  
pp. 18-31
Author(s):  
Karl Heusch ◽  
Johannes Botschek ◽  
Armin Skowronek
Keyword(s):  
Bronze Age ◽  
Middle Ages ◽  
Iron Age ◽  
Late Holocene ◽  
Early Holocene ◽  
Early Iron Age ◽  
Modern Times ◽  
Late Middle Ages

Abstract. The flood loams in the Sieg valley near Hennef were investigated with geomorphological, sedimentological and pedological methods. They are free of carbonate. Four late Holocene floodplain terraces can be seperated and dated. On the Upper Floodplain Terrace an Auenparabraunerde-Auenbraunerde (Fluvi-Luvic Cambisol) of early Iron Age was found. The pedogenesis on the older Middle Floodplain Terrace lead to a Typische Auenbraunerde (Fluvi-Eutric Cambisol) of Latene Age. The younger part of this terrace is covered by a Braunauenboden (Eutric Fluvisol) of late Middle Ages/modern times. The Lower Floodplain Terrace is the youngest formation, at most 200 years old. It is characterized by an Auengley/Auenregosol (Fluvi-Eutric Gleysol). The Parabraunerde (Luvisol) on the Weichselian Low Terrace is supposed to be of Bronze Age. That anthropogenic flood loams bury traces of a presumably early Holocene soil on the Low Terrace.

The church in the West Highlands in the late middle ages

2003 ◽  
Vol 54 (1) ◽  
pp. 23-46
Author(s):  
A. D. M. Barrell
Keyword(s):  
Middle Ages ◽  
The West ◽  
Late Middle Ages ◽  
The Church

Forma Dat Esse

2020 ◽  
Vol 23 (2) ◽  
pp. 423-446
Author(s):  
Sylvain Roudaut
Keyword(s):  
Middle Ages ◽  
Progressive Decline ◽  
De Trinitate ◽  
Late Middle Ages ◽  
History Of ◽  
The Middle Ages

Abstract This paper offers an overview of the history of the axiom forma dat esse, which was commonly quoted during the Middle Ages to describe formal causality. The first part of the paper studies the origin of this principle, and recalls how the ambiguity of Boethius’s first formulation of it in the De Trinitate was variously interpreted by the members of the School of Chartres. Then, the paper examines the various declensions of the axiom that existed in the late Middle Ages, and shows how its evolution significantly follows the progressive decline of the Aristotelian model of formal causality.

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