High-Resolution Peat Core Chronology Covering the Last 12 KYR Applying an Improved Peat Bog Sampling

Radiocarbon ◽  
2018 ◽  
Vol 60 (5) ◽  
pp. 1367-1378 ◽  
Author(s):  
Katalin Hubay ◽  
Mihály Braun ◽  
Sándor Harangi ◽  
László Palcsu ◽  
Marianna Túri ◽  
...  
Keyword(s):  
High Resolution ◽  
Accumulation Rate ◽  
Peat Bog ◽  
Acid Base ◽  
Peat Accumulation ◽  
Peat Core ◽  
Ams Dating ◽  
Different Depths ◽  
Peat Profile ◽  
Bleaching Step

ABSTRACTThis work focuses on building a high-resolution age-depth model for quantitative palaeoclimate study from the Mohos peat bog, East Carpathian mountains. The investigated core presents a continuous peat profile for the last 12 kyr. The chronology was based on 36 accelerator mass spectrometry radiocarbon (AMS 14C) analyses of the separated Sphagnum samples from different depths of the profile. Dry Sphagnum samples for AMS dating were prepared using the classic acid-base-acid (ABA) method followed with an oxidative bleaching step to get clean cellulose. Sphagnum cellulose samples were measured by AMS using the EnvironMICADAS at the ICER (Debrecen, Hungary). A high-resolution chronology was obtained with the use of Bayesian age-depth modeling. Peat accumulation rate has been calculated and the sections with variable accumulation rate values were observed along the profile.

High-Resolution Age-Depth Model of a Peat Bog in Poland as an Important Basis for Paleoenvironmental Studies

Radiocarbon ◽  
2014 ◽  
Vol 56 (1) ◽  
pp. 109-125 ◽  
Author(s):  
B Fiałkiewicz-Kozieł ◽  
P Kołaczek ◽  
N Piotrowska ◽  
A Michczyński ◽  
E Łokas ◽  
...  
Keyword(s):  
High Resolution ◽  
Industrial Revolution ◽  
Climatic Factors ◽  
Accumulation Rate ◽  
Bulk Composition ◽  
Water Level Fluctuations ◽  
Peat Bog ◽  
Agricultural Activity ◽  
Peat Accumulation ◽  
Peat Formation

This article focuses on constructing a high-resolution age-depth model for the Puścizna Mała peat bog located in Orawa-Nowy Targ Basin (S Poland). The chronology was established on the basis of both210Pb and14C measurements, and further confirmed by pollen diagrams and the peat bulk composition (density, ash content, and measurements of C, N, S). The137Cs profile revealed significant downward migration of this radionuclide and was not suitable for geochronological interpretation. The peat profile in southern Poland records almost 2000 yr of paleoecological and geochemical changes. Major historical events linked to anthropogenic and climatic changes are recorded in the investigated proxies, which confirm the reliability of the age-depth model. Specifically, the Roman period, Migration period, Medieval times, as well as the Industrial Revolution are reflected in the palynology and bulk composition of the peat. However, dating results obtained for the core segment between 22–45 cm are problematic when confronted with other analyses. The highest peat accumulation rate of 2 mm yr-1(AD 1300–1400 according to the age-depth model) is not compatible with the section of the highest peat decomposition revealed by lithological description. Moreover, the onset of a drastic decline of forests reflected in the palynological data and dated to AD 1280–1340 (40 cm) is difficult to explain in the light of historical data. Therefore, the lithology, bulk density, and pollen were used to validate the obtained age-depth model. External forcing factors on the peat formation process may be indicated, including agricultural activity, water-level fluctuations, and natural climatic factors, which paradoxically caused doubling of the obtained peat accumulation rate.

scholarly journals Holocene paleoclimate inferred from stable isotope (δ18O and δ13C) values in Sphagnum cellulose, Mohos peat bog, Romania

2021 ◽  
Author(s):  
Marianna Túri ◽  
Katalin Hubay ◽  
Mihály Molnár ◽  
Mihály Braun ◽  
Elemér László ◽  
...  
Keyword(s):  
Organic Matter ◽  
Stable Isotope ◽  
Accumulation Rate ◽  
Peat Bog ◽  
Cold Event ◽  
The Holocene ◽  
Peat Core ◽  
Organic Matter Accumulation ◽  
Long Duration ◽  
Using Data

AbstractWe measured stable isotopes (δ18O and δ13C) in Sphagnum cellulose that was extracted from a long peat core drilled in the ombrotrophic Mohos peat bog, Ciomadul Mountain, Romania. The 10-m-long peat profile spans the period from 11,800 cal yr BP to present. The δ18O and δ13C data indicate there were several cooling events and warm periods in the area of the Mohos peat bog during the Holocene. The 8.2-ka cold event, however, was not detected using δ18O and δ13C values. Response of the peat bog to changing environmental conditions was inferred using data on organic matter accumulation, independent of the stable isotope results. All cool periods during the Holocene, whether of short or long duration, were identified as times of reduced organic matter accumulation rate. Similarly, dry periods were also correlated with reduced accumulation rates of organic matter.

Tree line shifts, changing vegetation assemblages and permafrost dynamics on Galdhøpiggen (Jotunheimen, Norway) over the past ~4400 years

The Holocene ◽  
2021 ◽  
pp. 095968362110665
Author(s):  
Helen Hallang ◽  
Cynthia A Froyd ◽  
John F Hiemstra ◽  
Sietse O Los
Keyword(s):  
Scots Pine ◽  
Late Holocene ◽  
Accumulation Rate ◽  
Climatic Changes ◽  
Climatic Conditions ◽  
Tree Line ◽  
Peat Core ◽  
Modern Pollen ◽  
Modern Analogue ◽  
Downy Birch

An environmental reconstruction based on palynological evidence preserved in peat was carried out to examine late-Holocene alpine tree line dynamics in the context of past climatic changes on Galdhøpiggen (Jotunheimen, southern Norway). We analysed a peat core taken from a mire at the present-day tree line (1000 m a.s.l.), c. 450 m downslope from the lower limit of sporadic permafrost. We adopted a combination of commonly used indicators of species’ local presence to reconstruct past vegetation assemblages, such as the relative pollen abundance (%), pollen accumulation rate (PAR), and presence of indicator species. Additionally, fossil pollen from the peat sequence was compared to modern pollen from a surface moss polster to establish a modern analogue. The results were compared with studies covering the late-Holocene climatic changes in the area. The reconstruction demonstrates that a pine-dominated woodland reached above the present-day tree line at c. 4300 cal. yr BP, suggesting a warmer climate suitable for Scots pine ( Pinus sylvestris) growth at this altitude. Scots pine retreated to lower altitudes between c. 3400 and 1700 cal. yr BP, accompanied by the descent of the low-alpine shrub-dominated belt, in response to cooling climatic conditions. The colder period covered c. 1700–170 cal. yr BP, and an open downy birch ( Betula pubescens) woodland became widespread at 1000 m a.s.l., whilst pine remained sparse at this altitude. From c. 170 cal. yr BP onwards, warming allowed pine to re-establish its local presence alongside downy birch at 1000 m a.s.l.

High-resolution radiocarbon dating to reconstruct last century environmental changes in the pacific island of Espiritu Santo

2021 ◽  
Author(s):  
Giorgia Camperio ◽  
Caroline Welte ◽  
S. Nemiah Ladd ◽  
Matthew Prebble ◽  
Nathalie Dubois
Keyword(s):  
High Resolution ◽  
Radiocarbon Dating ◽  
Environmental Changes ◽  
Accumulation Rate ◽  
Sediment Cores ◽  
Volcanic Eruptions ◽  
High Accumulation ◽  
Sedimentary Records ◽  
The Pacific ◽  
Rapid Accumulation

<p>Espiritu Santo is one of the 82 islands of the archipelago of Vanuatu and is the largest, highest, and most biodiverse of the insular country. Climatic changes linked to El Niño and extreme events such as cyclones and volcanic eruptions are a daily challenge in this remote area. These events can be recorded in sedimentary archives. Here we present a multi-proxy investigation of sediment cores retrieved from two small lakes located on the West coast of Espiritu Santo. Although the records span the last millennium, high-resolution radiocarbon dating of macrofossils reveals a rapid accumulation of sediment in the past 100 years. The high accumulation rate coupled with the high-resolution dating of freshwater sediments allows us to compare the <sup>14</sup>C bomb curve with the biogeochemical proxies of the sedimentary records. The results can then be validated against written and oral historical records linked with the societal perception of recent environmental changes in this vulnerable ecosystem.</p><div> <div title="Translate selected text"></div> <div title="Play"></div> <div title="Copy text to Clipboard"></div> </div>

Variable charges of a red soil from different depths: Acid-base buffer capacity and surface complexation model

2018 ◽  
Vol 159 ◽  
pp. 107-115 ◽  
Author(s):  
Ying Wang ◽  
Pengfei Cheng ◽  
Fangbai Li ◽  
Tongxu Liu ◽  
Kuan Cheng ◽  
...  
Keyword(s):  
Buffer Capacity ◽  
Surface Complexation ◽  
Red Soil ◽  
Acid Base ◽  
Surface Complexation Model ◽  
Different Depths

Quantification of fluvial-peat interactions in the Pikeville formation Central Appalachian Basin, USA.

2021 ◽  
Author(s):  
Peter Wooldridge ◽  
Robert Duller ◽  
Rhodri Jerrett ◽  
Kyle Straub
Keyword(s):  
Accumulation Rate ◽  
Appalachian Basin ◽  
River Channels ◽  
Channel Depth ◽  
Peat Accumulation ◽  
Floodplain River ◽  
Basin Scale ◽  
Well Data ◽  
Fluvial Architecture ◽  
Sand Bodies

<p>Basin-scale fluvial architecture is, to a large extent, determined by the ability of river systems to migrate and avulse across their own floodplain. River avulsion takes place when a river aggrades by one channel depth to achieve super-elevation above the surrounding floodplain. However, peat enhancement of floodplain aggradation is likely to affect this fluvial behaviour and has received little attention. The interaction between river channels and peat-dominated floodplains is likely to have the effect of inhibiting or prolonging the conditions required for river avulsion, and so will impact on basin scale architecture during prolonged peat accumulation on floodplains. To elucidate and quantify the nature of this channel-floodplain interaction we investigate the coal-bearing clastic interval of the Carboniferous Pikeville Formation, Central Appalachian Basin, USA. Using a combination of well data and outcrop data, two coal horizons and intervening sand bodies, were mapped across an area of 5700 km<sup>2</sup> to ascertain overall basin-scale architecture. Comparison of the accumulation rate of the coal units (corrected for decompaction) with the synchronously deposited sand bodies suggests that extensive and rapid peat accumulation can increase avulsion timescales by 3 orders of magnitude and dramatically alter basin-scale fluvial architecture.</p>

scholarly journals A representative density profile of the North Greenland snowpack

2016 ◽  
Vol 10 (5) ◽  
pp. 1991-2002 ◽  
Author(s):  
Christoph Florian Schaller ◽  
Johannes Freitag ◽  
Sepp Kipfstuhl ◽  
Thomas Laepple ◽  
Hans Christian Steen-Larsen ◽  
...  
Keyword(s):  
Remote Sensing ◽  
High Resolution ◽  
Density Profile ◽  
Accumulation Rate ◽  
Sampling Technique ◽  
Data Sets ◽  
Accumulation Rates ◽  
The North ◽  
North Greenland ◽  
Good Agreement

Abstract. Along a traverse through North Greenland in May 2015 we collected snow cores up to 2 m depth and analyzed their density and water isotopic composition. A new sampling technique and an adapted algorithm for comparing data sets from different sites and aligning stratigraphic features are presented. We find good agreement of the density layering in the snowpack over hundreds of kilometers, which allows the construction of a representative density profile. The results are supported by an empirical statistical density model, which is used to generate sets of random profiles and validate the applied methods. Furthermore we are able to calculate annual accumulation rates, align melt layers and observe isotopic temperatures in the area back to 2010. Distinct relations of δ18O with both accumulation rate and density are deduced. Inter alia the depths of the 2012 melt layers and high-resolution densities are provided for applications in remote sensing.

scholarly journals Solar-like oscillations in subgiant and red-giant stars: mixed modes

2013 ◽  
Vol 9 (S301) ◽  
pp. 325-331 ◽  
Author(s):  
S. Hekker ◽  
A. Mazumdar
Keyword(s):  
High Resolution ◽  
Outer Part ◽  
Space Missions ◽  
Giant Stars ◽  
Internal Structures ◽  
Different Depths ◽  
Mixed Modes ◽  
Red Giant Stars ◽  
Red Giant

AbstractThanks to significant improvements in high-resolution spectrographs and the launch of dedicated space missions MOST, CoRoT and Kepler, the number of subgiants and red-giant stars with detected oscillations has increased significantly over the last decade. The amount of detail that can now be resolved in the oscillation patterns does allow for in-depth investigations of the internal structures of these stars. One phenomenon that plays an important role in such studies are mixed modes. These are modes that carry information of the inner radiative region as well as from the convective outer part of the star allowing to probe different depths of the stars.Here, we describe mixed modes and highlight some recent results obtained using mixed modes observed in subgiants and red-giant stars.

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