scholarly journals Geochemical properties and environmental impacts of seven Campanian tephra layers deposited between 40 and 38 ka BP in the varved lake sediments of Lago Grande di Monticchio, southern Italy

2015 ◽  
Vol 118 ◽  
pp. 67-83 ◽  
Author(s):  
Kristina Wutke ◽  
Sabine Wulf ◽  
Emma L. Tomlinson ◽  
Mark Hardiman ◽  
Peter Dulski ◽  
...  
Keyword(s):  
Lake Sediments ◽  
Environmental Impacts ◽  
Southern Italy ◽  
Geochemical Properties ◽  
Varved Lake Sediments ◽  
Tephra Layers

Shotgun DNA, pollen and biological multi-proxy analysis of Lateglacial lake sediments from Monticchio, Italy

2020 ◽  
Author(s):  
Laura Parducci ◽  
Kevin Nota ◽  
Willy Tinner ◽  
Jacqueline van Leeuwen ◽  
Pim van der Knaap ◽  
...  
Keyword(s):  
Lake Sediments ◽  
Southern Italy ◽  
Late Glacial ◽  
Plant Identification ◽  
Complementary Information ◽  
Biological Communities ◽  
Varved Lake Sediments ◽  
Late Glacial And Holocene ◽  
Taxonomic Groups ◽  
Metagenomic Approach

<p>We used shotgun DNA sequencing of the full metagenome preserved in varved lake sediments from southern Italy (Lago Grande di Monticchio) to investigate the whole diversity of taxonomic groups present. We combine sedimentary aDNA and pollen data as well as other biological multi-proxy data and tested if it was possible to correlate the relative abundances of plants and other biological communities to distinct climatic shifts that occurred between the Late Glacial and Holocene. In addition, we used the metabarcoding technique to compare the two sequencing approaches specifically for plants.</p><p>Our studies showed that the inhibition of DNA replication was almost absent in older (full glacial) sediment samples while it increased substantially in more recent samples. DNA provides a strong signal of plant community changes and a large number of new plant taxa were recorded. A comparison between sequencing approaches and proxies highlights differences and similarities and supports earlier findings that plants growing close to or within a lake are often recorded by DNA and that DNA provides important complementary information to that collected from palaeoecological analyses. Nevertheless, increasing DNA reference libraries and enrichment strategies prior to sequencing are necessary to improve the potential and accuracy of plant identification using the metagenomic approach.</p>

scholarly journals VARDA (VArved sediments DAtabase) – providing and connecting proxy data from annually laminated lake sediments

2020 ◽  
Author(s):  
Arne Ramisch ◽  
Alexander Brauser ◽  
Mario Dorn ◽  
Cecile Blanchet ◽  
Brian Brademann ◽  
...  
Keyword(s):  
High Resolution ◽  
Lake Sediments ◽  
Climate Models ◽  
Detailed Comparison ◽  
High Temporal Resolution ◽  
Proxy Data ◽  
Varved Sediments ◽  
Proxy Records ◽  
Data Compilation ◽  
Varved Lake Sediments

Abstract. Varved lake sediments provide long climatic records with high temporal resolution and low associated age uncertainty. Robust and detailed comparison of well-dated and annually laminated sediment records is crucial for reconstructing abrupt and regionally time-transgressive changes as well as validation of spatial and temporal trajectories of past climatic changes. The VARved sediments DAtabase (VARDA) presented here is the first data compilation for varve chronologies and associated palaeoclimatic proxy records. The current version 1.0 allows detailed comparison of published varve records from 95 lakes. VARDA is freely accessible and was created to assess outputs from climate models with high-resolution terrestrial palaeoclimatic proxies. VARDA additionally provides a technical environment that enables to explore the database of varved lake sediments using a connected data-model and can generate a state-of-the-art graphic representation of multi-site comparison. This allows to reassess existing chronologies and tephra events to synchronize and compare even distant varved lake records. Furthermore, the present version of VARDA permits to explore varve thickness data. In this paper, we report in detail on the data mining and compilation strategies for the identification of varved lakes and assimilation of high-resolution chronologies as well as the technical infrastructure of the database. Additional paleoclimate proxy data will be provided in forthcoming updates. The VARDA graph-database and user interface can be accessed online at https://varve.gfz-potsdam.de, all datasets of version 1.0 are available at http://doi.org/10.5880/GFZ.4.3.2019.003 (Ramisch et al., 2019).

scholarly journals An estimate of post-depositional remanent magnetization lock-in depth in organic rich varved lake sediments

2013 ◽  
Vol 110 ◽  
pp. 264-277 ◽  
Author(s):  
Ian Snowball ◽  
Anette Mellström ◽  
Emelie Ahlstrand ◽  
Eeva Haltia ◽  
Andreas Nilsson ◽  
...  
Keyword(s):  
Lake Sediments ◽  
Remanent Magnetization ◽  
Varved Lake Sediments ◽  
Lock In

Level of Lake Lahontan during Deposition of the Trego Hot Springs Tephra about 23,400 years ago

1983 ◽  
Vol 19 (3) ◽  
pp. 312-324 ◽  
Author(s):  
Jonathan O. Davis
Keyword(s):  
Lake Sediments ◽  
Hot Springs ◽  
Minor Element ◽  
Depositional Environments ◽  
Radiometric Dating ◽  
The North ◽  
Calcareous Tufa ◽  
Northern Nevada ◽  
Stratigraphic Position ◽  
Tephra Layers

AbstractThe Trego Hot Springs tephra bed is a silicic tephra about 23,400 yr old, found at several localities in pluvial lake sediments in northern Nevada, southern Oregon, and northeastern California. It has been characterized petrographically, by the major and minor element chemistry of its glass, and by its stratigraphic position with respect to other tephra layers. At a newly described locality on Squaw Creek, northwest of Gerlach, Nevada, at the north end of the Smoke Creek Desert, Trego Hot Springs tephra has been found in sediments of the Sehoo and Indian Lakes formations. The depositional environments of these sediments show that when the tephra fell, pluvial Lake Lahontan stood between 1256 and 1260 m, and that immediately thereafter the lake rose to at least 1275 m. These data corroborate earlier findings by Benson (Quaternary Research9, 300–318) from radiometric dating of calcareous tufa. However, the Lake Lahontan area has been affected by isostatic subsidence and rebound in response to changing water loads, so that caution is required in the use of lakeshore elevations in correlation.

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