scholarly journals Sediments Suggest Vikings May Have Been the First to Settle the Azores

Eos ◽  
2022 ◽  
Vol 103 ◽  
Author(s):  
Santiago Fl�rez
Keyword(s):  
Climate Change ◽  
Lake Sediments ◽  
Multidisciplinary Team ◽  
Historical Sources

A multidisciplinary team studying lake sediments and climate change found evidence that the archipelago was inhabited 700 years earlier than historical sources claim.

scholarly journals Dropstones in Lacustrine Sediments as a Record of Snow Avalanches—A Validation of the Proxy by Combining Satellite Imagery and Varve Chronology at Kenai Lake (South-Central Alaska)

Quaternary ◽  
2019 ◽  
Vol 2 (1) ◽  
pp. 11 ◽  
Author(s):  
Sien Thys ◽  
Maarten Van Daele ◽  
Nore Praet ◽  
Britta Jensen ◽  
Thomas Van Dyck ◽  
...  
Keyword(s):  
Climate Change ◽  
Lake Sediments ◽  
Satellite Imagery ◽  
Variable Temperature ◽  
Sediment Cores ◽  
Snow Avalanche ◽  
Snow Avalanches ◽  
Climate Data ◽  
Varve Chronology ◽  
South Central

Snow avalanches cause many fatalities every year and damage local economies worldwide. The present-day climate change affects the snowpack and, thus, the properties and frequency of snow avalanches. Reconstructing snow avalanche records can help us understand past variations in avalanche frequency and their relationship to climate change. Previous avalanche records have primarily been reconstructed using dendrochronology. Here, we investigate the potential of lake sediments to record snow avalanches by studying 27 < 30-cm-long sediment cores from Kenai Lake, south-central Alaska. We use X-ray computed tomography (CT) to image post-1964 varves and to identify dropstones. We use two newly identified cryptotephras to update the existing varve chronology. Satellite imagery is used to understand the redistribution of sediments by ice floes over the lake, which helps to explain why some avalanches are not recorded. Finally, we compare the dropstone record with climate data to show that snow avalanche activity is related to high amounts of snowfall in periods of relatively warm or variable temperature conditions. We show, for the first time, a direct link between historical snow avalanches and dropstones preserved in lake sediments. Although the lacustrine varve record does not allow for the development of a complete annual reconstruction of the snow avalanche history in the Kenai Lake valley, our results suggest that it can be used for long-term decadal reconstructions of the snow-avalanche history, ideally in combination with similar records from lakes elsewhere in the region.

scholarly journals Influence of late-Holocene climate change on the solid-phase speciation and long-term stability of arsenic in sub-Arctic lake sediments

2020 ◽  
Vol 709 ◽  
pp. 136115 ◽  
Author(s):  
Clare B. Miller ◽  
Michael B. Parsons ◽  
Heather E. Jamieson ◽  
Omid H. Ardakani ◽  
Braden R.B. Gregory ◽  
...  
Keyword(s):  
Climate Change ◽  
Lake Sediments ◽  
Late Holocene ◽  
Solid Phase ◽  
Holocene Climate ◽  
Arctic Lake ◽  
Term Stability ◽  
Long Term Stability ◽  
Holocene Climate Change

Palynomorphs in southern Western Australian lake sediments: evidence of climate change and hypersalinity during the Cenozoic

Palynology ◽  
2020 ◽  
pp. 1-14
Author(s):  
Carlos A. Sanchez Botero ◽  
Francisca E. Oboh-Ikuenobe ◽  
Lutfia Grabel ◽  
Onema C. Adojoh
Keyword(s):  
Climate Change ◽  
Lake Sediments ◽  
Western Australian

Non-residual Sr of the sediments in Daihai Lake as a good indicator of chemical weathering

2013 ◽  
Vol 79 (2) ◽  
pp. 284-291 ◽  
Author(s):  
Yan Zeng ◽  
Jingan Chen ◽  
Jule Xiao ◽  
Liang Qi
Keyword(s):  
Climate Change ◽  
Lake Sediments ◽  
Lake Water ◽  
Chemical Weathering ◽  
Environmental Processes ◽  
Daihai Lake ◽  
Variation Patterns ◽  
Potential Indicator ◽  
Physical Erosion ◽  
Different Sources

AbstractThe Rb/Sr ratio of lake sediments has been demonstrated to be a potential indicator of chemical weathering by increasing work. However, Rb and Sr in lake sediments are derived from both chemical weathering and physical erosion. Rb and Sr of different forms in lake sediments may record different environmental processes and information. In this study, the variation patterns of Rb and Sr of different forms in sediments of Daihai Lake were investigated. The results show that Rb and Sr of different forms display noticeably different variation patterns due to their different sources and associated environmental processes. Using the Rb/Sr ratios of bulk lake sediments to reflect chemical weathering is not accurate. The non-residual Sr of the sediments without detrital carbonates, representing the Sr leached from the catchment, can be used as an index of chemical weathering because the weathering of Sr minerals is very sensitive to climate change, and the non-residual Sr content of the sediment is determined more by Sr2 + influx than by the physicochemical conditions of lake water. The correspondence between the non-residual Sr and TIC/TOC in Daihai Lake also indicates that the non-residual Sr of the sediments is a good indicator of chemical weathering in the catchment.

High resolution sediment and vegetation responses to Younger Dryas climate change in varved lake sediments from Meerfelder Maar, Germany

1999 ◽  
Vol 18 (3) ◽  
pp. 321-329 ◽  
Author(s):  
Achim Brauer ◽  
Christoph Endres ◽  
Christina Günter ◽  
Thomas Litt ◽  
Martina Stebich ◽  
...  
Keyword(s):  
Climate Change ◽  
High Resolution ◽  
Lake Sediments ◽  
Younger Dryas ◽  
Vegetation Responses ◽  
Varved Lake Sediments

scholarly journals Palaeoflood activity and climate change over the last 1400 years recorded by lake sediments in the north-west European Alps

2013 ◽  
Vol 28 (2) ◽  
pp. 189-199 ◽  
Author(s):  
B. Wilhelm ◽  
F. Arnaud ◽  
P. Sabatier ◽  
O. Magand ◽  
E. Chapron ◽  
...  
Keyword(s):  
Climate Change ◽  
Lake Sediments ◽  
European Alps ◽  
North West ◽  
The North ◽  
West European

Constructing paleoclimate networks from annually laminated lake sediments – the VARDA database

2020 ◽  
Author(s):  
Arne Ramisch ◽  
Alexander Brauser ◽  
Mario Dorn ◽  
Cecile Blanchet ◽  
Brian Brademann ◽  
...  
Keyword(s):  
Climate Change ◽  
Lake Sediments ◽  
Large Scale ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Volcanic Eruptions ◽  
Scale Model ◽  
Graph Database ◽  
Varve Thickness ◽  
Novel Approach

&lt;p&gt;Reconstructing global patterns of past climate change requires large-scale networks of paleoclimatic archives. Generating paleoclimatic networks relies on precise synchronization of individual records with robust age control. The detailed age constrains of continuous varved lake sediments and the good preservation of isochrones from supra-regional extreme events make these records ideal for constructing large scale continental paleoclimatic networks. Yet, a global synthesis of varved lake archives is missing.&lt;/p&gt;&lt;p&gt;Here we present the VARved sediments DAtabase 1.0 (VARDA 1.0), the first global data compilation for varve chronologies and associated palaeoclimatic proxy records. VARDA 1.0 uses a connected data model provided by a state-of-the-art graph database, enabling custom generations of synchronized paleoclimatic networks. We report on compilation strategies for the identification of varved lakes and assimilation of high-resolution chronologies. Existing chronologies have been re-assessed and harmonized using a novel approach that infers information on sedimentation rates enclosed in varve thickness records. This information provides detailed information on the priors required for Bayesian age-depth modelling and strongly improves these results. Additionally, a synthesis of tephra layers from volcanic eruptions provides supra-regional isochrones for synchronizing even distant varved lake records. The current version (VARDA 1.0) comprises 261 datasets from 95 varved lake archives, including chronological information from &lt;sup&gt;14&lt;/sup&gt;C dating and varve thickness measurements, but also palaeoclimatological proxy data. We further explore potential applications of such networks in paleoclimatic studies, such as identifying leads and lags of regional climate change, large-scale model-data comparisons or differentiated proxy responses between archives. The VARDA graph-database and user interface can be accessed online at https://varve.gfz-potsdam.de.&lt;/p&gt;

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