Occurence of flood laminae in sediments of Ammersee

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Auteurs principaux: Czymzik, Markus, von Grafenstein, Ulrich, Naumann, Rudolf, Brauer, Achim
Format: Dataset Open Access
Langue:en
Publié: PANGAEA 2010
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author Czymzik, Markus
von Grafenstein, Ulrich
Naumann, Rudolf
Brauer, Achim
author_facet Czymzik, Markus
von Grafenstein, Ulrich
Naumann, Rudolf
Brauer, Achim
collection Datos científicos de ciencias marinas y ambientales
contents A 450 year spring-summer flood layer time series at seasonal resolution has been established from the varved sediment record of Lake Ammersee (southern Germany), applying a novel methodological approach. The main results are (1) the attainment of a precise chronology by microscopic varve counting, (2) the identification of detrital layers representing flood-triggered fluxes of catchment material into the lake, and (3) the recognition of the seasonality of these flood layers from their microstratigraphic position within a varve. Tracing flood layers in a proximal and a distal core and correlating them by application of the precise chronology provided information on the depositional processes. Comparing the seasonal flood layer record with daily runoff data of the inflowing River Ammer for the period from 1926 to 1999 allowed the definition of an approximate threshold in flood magnitude above which the formation of flood layers becomes very likely. Moreover, it was possible for the first time to estimate the "completeness" of the flood layer time series and to recognize that mainly floods in spring and summer, representing the main flood seasons in this region, are well preserved in the sediment archive. Their frequency distribution over the entire 450 year time series is not stationary but reveals maxima for colder periods of the Little Ice Age when solar activity was reduced. The observed spring-summer flood layer frequency further shows trends similar to those of the occurrence of flood-prone weather regimes since A.D. 1881, probably suggesting a causal link between solar variability and changes in midlatitude atmospheric circulation patterns.
format Dataset Open Access
id pangaea_https___doi_org_10_1594_PANGAEA_746240
institution PANGAEA
language en
publishDate 2010
publisher PANGAEA
record_format pangaea
spellingShingle Occurence of flood laminae in sediments of Ammersee
Czymzik, Markus
von Grafenstein, Ulrich
Naumann, Rudolf
Brauer, Achim
Age; AGE; Ammersee, Bavaria, Germany; AS_07-P1; Flood layer; PCUWI; Piston corer, UWITEC
A 450 year spring-summer flood layer time series at seasonal resolution has been established from the varved sediment record of Lake Ammersee (southern Germany), applying a novel methodological approach. The main results are (1) the attainment of a precise chronology by microscopic varve counting, (2) the identification of detrital layers representing flood-triggered fluxes of catchment material into the lake, and (3) the recognition of the seasonality of these flood layers from their microstratigraphic position within a varve. Tracing flood layers in a proximal and a distal core and correlating them by application of the precise chronology provided information on the depositional processes. Comparing the seasonal flood layer record with daily runoff data of the inflowing River Ammer for the period from 1926 to 1999 allowed the definition of an approximate threshold in flood magnitude above which the formation of flood layers becomes very likely. Moreover, it was possible for the first time to estimate the "completeness" of the flood layer time series and to recognize that mainly floods in spring and summer, representing the main flood seasons in this region, are well preserved in the sediment archive. Their frequency distribution over the entire 450 year time series is not stationary but reveals maxima for colder periods of the Little Ice Age when solar activity was reduced. The observed spring-summer flood layer frequency further shows trends similar to those of the occurrence of flood-prone weather regimes since A.D. 1881, probably suggesting a causal link between solar variability and changes in midlatitude atmospheric circulation patterns.
title Occurence of flood laminae in sediments of Ammersee
topic Age; AGE; Ammersee, Bavaria, Germany; AS_07-P1; Flood layer; PCUWI; Piston corer, UWITEC
url https://doi.org/10.1594/PANGAEA.746240