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Quaternary, Volume 2, Issue 3 (September 2019)

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Cover Story (view full-size image) New insights into the geology of the Pleistocene and Holocene deposits in the Middle Cam valley [...] Read more.
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Open AccessArticle
Acidification Assessment after Peat Bog Drainage in the Catalan Pyrenees (NE Iberia)
Quaternary 2019, 2(3), 32; https://doi.org/10.3390/quat2030032 - 18 Sep 2019
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Abstract
The Pyrenean range (NE Iberian Peninsula) has some favourable lithological and climatic conditions (iron-rich parent materials and udic moisture regimes) for the formation of acid sulfate soils (ASS) that have not been reported on from the region until now. The analyses of a [...] Read more.
The Pyrenean range (NE Iberian Peninsula) has some favourable lithological and climatic conditions (iron-rich parent materials and udic moisture regimes) for the formation of acid sulfate soils (ASS) that have not been reported on from the region until now. The analyses of a drained peat bog near València d’Àneu revealed a pH (1:2.5) of 3.7. We hypothesize that it contained sulfidic materials that were oxidized during drainage, which could have caused its acidification. The main goal of this study is to understand the characteristics and the potential acidity of these organic soils and the consequences that this could generate in the current environment. In order to do so, several profiles were described and sampled in the field for chemical and micromorphological analyses. The results show that the oxidation of the newly formed pyrite in the soil or pyrite contained in the Cambro–Ordovician parent material was responsible for the low pH and high electrical conductivity (EC). The soils still contain sulfidic materials at present, which could be oxidized in the future, with the consequent risk for water quality. The results will be useful to evaluate the risk of other peats in the Pyrenees becoming acid sulfate soils if drained. Full article
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Open AccessReview
Speleothem Records from the Eastern Part of Europe and Turkey—Discussion on Stable Oxygen and Carbon Isotopes
Quaternary 2019, 2(3), 31; https://doi.org/10.3390/quat2030031 - 18 Sep 2019
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Abstract
The region comprising of East Central Europe, South East Europe and Turkey contributed to the SISAL (Speleothem Isotopes Synthesis and AnaLysis) global database with stable carbon and oxygen isotope time-series from 18 speleothems from 14 caves. The currently available oldest record from the [...] Read more.
The region comprising of East Central Europe, South East Europe and Turkey contributed to the SISAL (Speleothem Isotopes Synthesis and AnaLysis) global database with stable carbon and oxygen isotope time-series from 18 speleothems from 14 caves. The currently available oldest record from the studied region is the ABA-2 flowstone record (Abaliget Cave; Hungary) reaching back to MIS 6. The temporal distribution of the compiled 18 records from the region points out a ~20 kyr-long period, centering around 100 ka BP, lacking speleothem stable isotope data. The regional subset of SISAL_v1 records displays a continuous coverage for the past ~90 kyr for both δ13C and δ18O, with a mean temporal resolution of ~12 yr for the Holocene, and >50 yr for the pre-Holocene period. The highest temporal resolution both for the Holocene and the pre-Holocene was achieved in the So-1 record (Sofular Cave; Turkey). The relationship between modern day precipitation δ18O (amount weighted annual and winter season mean values; 1961–2017) and climatological parameters was evaluated. The strong positive correlation found in East Central Europe reinforces the link between modern day precipitation δ18O, temperature and large-scale circulation (North Atlantic Oscillation) expected to be preserved in the speleothem δ18O record; while a negative relationship was documented between precipitation amount and oxygen isotope compositions in South East Europe. Variations of δ13C values are primarily interpreted as reflecting dry/wet periods across the region. Elevation gradients from three non-overlapping periods of the last ~5 kyr indicated elevation gradients around −0.26‰ per 100 m−1 for calcite δ18O. Full article
(This article belongs to the Special Issue Speleothem Records and Climate)
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Open AccessArticle
Significance of the High Abundance of Pentacyclic Triterpenyl and Hopenyl Acetates in Sphagnum Peat Bogs from Northern Spain
Quaternary 2019, 2(3), 30; https://doi.org/10.3390/quat2030030 - 21 Aug 2019
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Abstract
Global warming is expected to increase the rate of CH4 emission from acidic peatlands leading to an increased interest on its mechanisms of formation. The main routes are through the reduction of CO2 by molecular hydrogen and through the cleavage of [...] Read more.
Global warming is expected to increase the rate of CH4 emission from acidic peatlands leading to an increased interest on its mechanisms of formation. The main routes are through the reduction of CO2 by molecular hydrogen and through the cleavage of acetate. A predominance of the former, a reaction which also competes with homoacetogenesis to form acetate, may enrich the media in acetate, which could potentially be incorporated in the peat molecular markers. Acetates of triterpenoid biomarkers have been identified in peats and lake sediments and related to the input of higher plants. Nevertheless, the acetyl derivatives are found in very low amounts in fresh plants and in much lower amount than other derivatives with alcohol or ketone functional groups. The dichloromethane/methanol extracts of Asturian peat bog profiles (North Spain) were analyzed using gas chromatography/mass spectrometry (GC/MS) and compound-specific-isotope-analysis (CSIA). They show abundance of acetates of compounds with oleanane, ursane, and lupane skeletons derived from higher plants and with hopane skeleton, which can be considered a characteristic of these peats. Two families of 3-oxyhopenyl acetates with -17(21)- and -22(29)- configurations were detected in the upper part of the peat profiles, having a δ13C isotopic composition enriched by 4‰ compared with that of higher plant triterpenoids, and similar to that of microorganism-derived regular hopanoids. Both the acetate and ketone derivatives with the oxygenated functionality at C-3 were generally present in a given extract and tended to accumulate at certain depth in the profiles and in specific levels. The widespread occurrence of acetyl-derivatives, their higher concentration in the deeper layers of the peat, the fact that the acetates correspond to different compound families of diverse source and the very low amount of acetates identified in Ericaceae-contributing to the peat compared to the alcohols suggest that they were formed in the peat under particularly favorable environmental conditions. We postulate that these conditions could have been the existence of a medium enriched in acetic acid produced by the dominance of hydrogenotrophic methanogenesis and/or homoacetogenesis over acetoclastic methanogenesis. This phenomenon that has been preferentially described in Sphagnum bogs at high latitudes, and in the deeper layers of peat, appears to be also present in the temperate peats of the Asturian coast. Full article
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Open AccessArticle
Last Interglacial Climate in Northern Sweden—Insights from a Speleothem Record
Quaternary 2019, 2(3), 29; https://doi.org/10.3390/quat2030029 - 20 Aug 2019
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Abstract
Continental records with absolute dates of the timing and progression of climatic conditions during the Last Interglacial (LIG) from northern Europe are rare. Speleothems from northern Europe have a large potential as archives for LIG environmental conditions since they were formed in sheltered [...] Read more.
Continental records with absolute dates of the timing and progression of climatic conditions during the Last Interglacial (LIG) from northern Europe are rare. Speleothems from northern Europe have a large potential as archives for LIG environmental conditions since they were formed in sheltered environments and may be preserved beneath ice sheets. Here, we present δ13C and δ18O values from speleothem Kf-21, from Korallgrottan in Jämtland (northwest Sweden). Kf-21 is dated with five MC-ICPMS U-Th dates with errors smaller than ~1 ka. Kf-21 started forming at ~130.2 ka and the main growth phase with relatively constant growth rates lasted from 127.3 ka to 124.4 ka, after which calcite formation ceased. Both δ13C and δ18O show rapid shifts but also trends, with a range of values within their Holocene counterparts from Korallgrottan. Our results indicate an early onset of the LIG in northern Europe with ice-free conditions at ~130 ka. Higher growth rates combined with more negative δ18O values between ~127.3 and 126.8 ka, interpreted here as warmer and more humid conditions, as well as indications of a millennial-scale cold spell centered at 126.2 ka, resemble findings from speleothem records from other parts of Europe, highlighting that these were regional scale climatic patterns. Full article
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Open AccessArticle
Paleoamerican Occupation, Stone Tools from the Cueva del Medio, and Considerations for the Late Pleistocene Archaeology in Southern South America
Quaternary 2019, 2(3), 28; https://doi.org/10.3390/quat2030028 - 12 Aug 2019
Viewed by 472
Abstract
Archaeological excavations at the Cueva del Medio performed during the 1980s and 1990s yielded an important record of both faunal and stone tool remains, as well as data, to discuss issues that occurred during the Terminal Pleistocene. Due to that, the shaped Paleoamerican [...] Read more.
Archaeological excavations at the Cueva del Medio performed during the 1980s and 1990s yielded an important record of both faunal and stone tool remains, as well as data, to discuss issues that occurred during the Terminal Pleistocene. Due to that, the shaped Paleoamerican artifacts collected in the author’s excavations were partially informed. The present article provides unpublished data on the field-work, the results of a techno-morphological analysis of the stone tools, and considerations about early hunter-gatherer societies along with their regional paleo-environmental interactions, as well other topics regarding the regional archaeological process during the last millennium of the Pleistocene. Findings from there have been extremely useful for discussing diverse paleo-ecological and archaeological topics and have extended the knowledge and discussions about different Pleistocene scientific issues, mainly related with flora, fauna, and the colonization of southern Patagonia. Full article
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Open AccessArticle
Approach for Analysis of Land-Cover Changes and Their Impact on Flooding Regime
Quaternary 2019, 2(3), 27; https://doi.org/10.3390/quat2030027 - 28 Jul 2019
Viewed by 522
Abstract
This study focused on the analysis of land-use/land-cover changes and their impact on flood runoff, flood hazards and inundation, focusing in the Pampanga River basin of the Philippines. The land-cover maps for the years 1996 and 2016 were generated using Landsat images, and [...] Read more.
This study focused on the analysis of land-use/land-cover changes and their impact on flood runoff, flood hazards and inundation, focusing in the Pampanga River basin of the Philippines. The land-cover maps for the years 1996 and 2016 were generated using Landsat images, and the land cover changes were analyzed using TerrSet Geospatial Monitoring and Modeling System (TGMMS). Based on an empirical approach and considering variable factors, the land-cover maps for the future were predicted using Land Change Modeler (LCM). After preparation of land-cover maps for past and future years, flood characteristics were analyzed using a distributed hydrological model named the rainfall runoff inundation (RRI) model with a land-cover map for different years. The impacts of land cover changes on flood runoff, flood volume and flood inundation were analyzed for 50- and 100-year floods. The results show that flood runoff, flood inundation volume and flood extent areas may increase in the future due to land-cover change in the basin. Full article
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Open AccessReview
The Asian Summer Monsoon: Teleconnections and Forcing Mechanisms—A Review from Chinese Speleothem δ18O Records
Quaternary 2019, 2(3), 26; https://doi.org/10.3390/quat2030026 - 23 Jul 2019
Viewed by 654
Abstract
Asian summer monsoon (ASM) variability significantly affects hydro-climate, and thus socio-economics, in the East Asian region, where nearly one-third of the global population resides. Over the last two decades, speleothem δ18O records from China have been utilized to reconstruct ASM variability [...] Read more.
Asian summer monsoon (ASM) variability significantly affects hydro-climate, and thus socio-economics, in the East Asian region, where nearly one-third of the global population resides. Over the last two decades, speleothem δ18O records from China have been utilized to reconstruct ASM variability and its underlying forcing mechanisms on orbital to seasonal timescales. Here, we use the Speleothem Isotopes Synthesis and Analysis database (SISAL_v1) to present an overview of hydro-climate variability related to the ASM during three periods: the late Pleistocene, the Holocene, and the last two millennia. We highlight the possible global teleconnections and forcing mechanisms of the ASM on different timescales. The longest composite stalagmite δ18O record over the past 640 kyr BP from the region demonstrates that ASM variability on orbital timescales is dominated by the 23 kyr precessional cycles, which are in phase with Northern Hemisphere summer insolation (NHSI). During the last glacial, millennial changes in the intensity of the ASM appear to be controlled by North Atlantic climate and oceanic feedbacks. During the Holocene, changes in ASM intensity were primarily controlled by NHSI. However, the spatio-temporal distribution of monsoon rain belts may vary with changes in ASM intensity on decadal to millennial timescales. Full article
(This article belongs to the Special Issue Speleothem Records and Climate)
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Open AccessArticle
The Apparent Resilience of the Dry Tropical Forests of the Nicaraguan Region of the Central American Dry Corridor to Variations in Climate Over the Last C. 1200 Years
Quaternary 2019, 2(3), 25; https://doi.org/10.3390/quat2030025 - 18 Jul 2019
Viewed by 483
Abstract
The Central American Dry Corridor (CADC) is the most densely populated area of the Central American Isthmus and is subject to the greatest variability in precipitation between seasons. The vegetation of this region is composed of Dry Tropical Forests (DTF), which are suggested [...] Read more.
The Central American Dry Corridor (CADC) is the most densely populated area of the Central American Isthmus and is subject to the greatest variability in precipitation between seasons. The vegetation of this region is composed of Dry Tropical Forests (DTF), which are suggested to be highly susceptible to variations in climate and anthropogenic development. This study examines the vulnerability of past DTF surrounding the Asese peninsula, Nicaragua to climatic and anthropogenic disturbances over the past c. 1200 years. Past vegetation, climate, burning, and animal abundance were reconstructed using proxy analysis of fossil pollen, diatoms, macroscopic charcoal, and Sporormiella. Results from this research suggest that DTF have been highly resilient to past climatic and anthropogenic perturbations. Changes in DTF structure and composition appear to be linked to the abundance and intensity of fire. Pre-Columbian anthropogenic impacts on DTF are not detected in the record; however, DTF taxa decline slightly after European contact (1522 C.E.). Overall the DTF for the Nicaraguan region of the CADC were found to be highly resilient to both climatic and anthropogenic disturbances, suggesting that this region will continue to be resilient in the face of future population expansion and climatic variation. Full article
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Open AccessArticle
The Geology of the Middle Cam Valley, Cambridgeshire, UK
Quaternary 2019, 2(3), 24; https://doi.org/10.3390/quat2030024 - 12 Jul 2019
Viewed by 554
Abstract
This study offers a new understanding of the stratigraphy and context of the Pleistocene (including Elsterian and Weichselian) and Holocene deposits of the Middle Cam valley, Cambridgeshire, United Kingdom, and provides a unique and detailed view of the sediment architecture of these valley-fill [...] Read more.
This study offers a new understanding of the stratigraphy and context of the Pleistocene (including Elsterian and Weichselian) and Holocene deposits of the Middle Cam valley, Cambridgeshire, United Kingdom, and provides a unique and detailed view of the sediment architecture of these valley-fill and interfluve sediments. The new insights into the geology of the area, including dating, pollen analyses, and sediment architecture, are presented with reference to a series of nine cross-sections through Holocene and Pleistocene deposits, as well as Cretaceous bedrock across the region. The structural geology of the bedrock and the stratigraphic arrangement of younger deposits are used to explain the landscape evolution of the area. Full article
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Open AccessReview
Using Annual Resolution Pollen Analysis to Synchronize Varve and Tree-Ring Records
Quaternary 2019, 2(3), 23; https://doi.org/10.3390/quat2030023 - 08 Jul 2019
Viewed by 598
Abstract
Fossil wood and varved lake sediments allow proxy analysis with exceptionally high, (sub-)annual resolution. Both archives provide dating through ring and layer counting, yet with different accuracy. In wood, counting errors are small and can be eliminated through cross-dating because tree-rings show regionally [...] Read more.
Fossil wood and varved lake sediments allow proxy analysis with exceptionally high, (sub-)annual resolution. Both archives provide dating through ring and layer counting, yet with different accuracy. In wood, counting errors are small and can be eliminated through cross-dating because tree-rings show regionally synchronous patterns. In varved sediments, counting errors are larger and cross-dating is hampered by missing regional patterns in varve parameters. Here, we test whether annual pollen analysis is suited to synchronize varve records. To that end, annual pollen deposition was estimated in three short cores from two lakes in north-eastern Germany for the period 1980–2017 CE. Analysis has focused on Fagus sylvatica and Picea abies, which show the strongest annual variations in flowering (mast). For both tree taxa, annual flowering variations recorded by forest and pollen monitoring are well represented in varved lake sediments, hence indeed allow us to synchronize the records. Some pollen mast events were not recognized, which may relate to sampling uncertainties, redeposition or regional variations in flowering. In Fagus sylvatica, intense flowering limits wood growth in the same year. Peaks in pollen deposition hence correlate with minima in tree-ring width, which provides a link between varved lake sediments and fossil wood. Full article
(This article belongs to the Special Issue Annually Laminated Lake Sediments)
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