the holocene
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2022 ◽  
Vol 277 ◽  
pp. 107297
Author(s):  
Mary Robles ◽  
Odile Peyron ◽  
Elisabetta Brugiapaglia ◽  
Guillemette Ménot ◽  
Lucas Dugerdil ◽  
...  

2022 ◽  
Vol 18 (1) ◽  
pp. 23-44
Author(s):  
Irene Schimmelpfennig ◽  
Joerg M. Schaefer ◽  
Jennifer Lamp ◽  
Vincent Godard ◽  
Roseanne Schwartz ◽  
...  

Abstract. Mid-latitude mountain glaciers are sensitive to local summer temperature changes. Chronologies of past glacier fluctuations based on the investigation of glacial landforms therefore allow for a better understanding of natural climate variability at local scale, which is relevant for the assessment of the ongoing anthropogenic climate warming. In this study, we focus on the Holocene, the current interglacial of the last 11 700 years, which remains a matter of dispute regarding its temperature evolution and underlying driving mechanisms. In particular, the nature and significance of the transition from the early to mid-Holocene and of the Holocene Thermal Maximum (HTM) are still debated. Here, we apply an emerging approach by combining in situ cosmogenic 10Be moraine and 10Be–14C bedrock dating from the same site, the forefield of Steingletscher (European Alps), and reconstruct the glacier's millennial recession and advance periods. The results suggest that, subsequent to the final deglaciation at ∼10 ka, the glacier was similar to or smaller than its 2000 CE extent for ∼7 kyr. At ∼3 ka, Steingletscher advanced to an extent slightly outside the maximum Little Ice Age (LIA) position and until the 19th century experienced sizes that were mainly confined between the LIA and 2000 CE extents. These findings agree with existing Holocene glacier chronologies and proxy records of summer temperatures in the Alps, suggesting that glaciers throughout the region were similar to or even smaller than their 2000 CE extent for most of the early and mid-Holocene. Although glaciers in the Alps are currently far from equilibrium with the accelerating anthropogenic warming, thus hindering a simple comparison of summer temperatures associated with modern and paleo-glacier sizes, our findings imply that the summer temperatures during most of the Holocene, including the HTM, were similar to those at the end of the 20th century. Further investigations are necessary to refine the magnitude of warming and the potential HTM seasonality.


Author(s):  
А. Л. Заика ◽  
А. М. Клементьев

Изучение древнего наскального искусства требует междисциплинарного подхода. Cотрудничество исследователей петроглифов и палеозоологов позволяет провести реконструкцию состава палеофауны региона, помогает в интерпретации териоморфных образов. Предметом изучения данной статьи являются похожие на быков изображения в наскальном искусстве р. Ангара. Многие изображения датируются эпохой неолита - ранней бронзы. Причины их появления в таежном наскальном искусстве могли быть различными: влияние художественной традиции окуневской культуры с юга; стилизация образа лося или оленя; мифологизация образов таежных животных; наличие для древнего художника реальной натуры - дикого быка. Согласно данным палеозоологии в эпоху голоцена на Ангаре обитали реликтовые животные - бизоны, туры. Возможно, они обитали и на Среднем Енисее. Это позволило высказать предположение, что в наскальном искусстве изображен дикий бык, на которого охотился древний человек. The study of ancient rock art requires an interdisciplinary approach. Active cooperation of rock art researchers and paleozoologists makes it possible to reconstruct the composition of the paleofauna, to interpret theriomorphic images. The subject of the article is images similar to bulls in rock art on the Angara River. Many of the images date back to the Neolithic - early Bronze Age. The reasons for their appearance in taiga zone rock art could be diff erent: the infl uence of artistic tradition of the Okunev culture from the South; stylization of the image of an elk or a deer; mythologization of the images of taiga zone animals; the presence of a real animal in the nature - a wild bull. According to paleozoological data of the Holocene Epoch the Angara River valley was inhabited by relict animals - bisons, tours. Perhaps, they also lived in the Middle Yenisei. Therefore, we suggest that some petroglyphs depict a wild bull, which was hunted by an ancient man.


2022 ◽  
Author(s):  
Michael Sigl ◽  
Matthew Toohey ◽  
Joseph R. McConnell ◽  
Jihong Cole-Dai ◽  
Mirko Severi

Abstract. The injection of sulfur into the stratosphere by volcanic eruptions is the dominant driver of natural climate variability on interannual-to-multidecadal timescales. Based on a set of continuous sulfate and sulfur records from a suite of ice cores from Greenland and Antarctica, the HolVol v.1.0 database includes estimates of the magnitudes and approximate source latitudes of major volcanic stratospheric sulfur injection (VSSI) events for the Holocene (from 9500 BCE or 11500 year BP to 1900 CE), constituting an extension of the previous record by 7000 years. The database incorporates new-generation ice-core aerosol records with sub-annual temporal resolution and demonstrated sub-decadal dating accuracy and precision. By tightly aligning and stacking the ice-core records on the WD2014 chronology from Antarctica we resolve long-standing previous inconsistencies in the dating of ancient volcanic eruptions that arise from biased (i.e. dated too old) ice-core chronologies over the Holocene for Greenland. We reconstruct a total of 850 volcanic eruptions with injections in excess of 1 TgS, of which 329 (39 %) are located in the low latitudes with bipolar sulfate deposition, 426 (50 %) are located in the Northern Hemisphere (NH) extratropics and 88 (10 %) are located in the Southern Hemisphere (SH) extratropics. The spatial distribution of reconstructed eruption locations is in agreement with prior reconstructions for the past 2,500 years, and follows the global distribution of landmasses. In total, these eruptions injected 7410 TgS in the stratosphere, for which tropical eruptions accounted for 70 % and NH extratropics for 25 %. A long-term latitudinally and monthly resolved stratospheric aerosol optical depth (SAOD) time series is reconstructed from the HolVol VSSI estimates, representing the first Holocene-scale reconstruction constrained by Greenland and Antarctica ice cores. These new long-term reconstructions of past VSSI and SAOD variability confirm evidence from regional volcanic eruption chronologies (e.g., from Iceland) in showing that the early Holocene (9500–7000 BCE) experienced a higher number of volcanic eruptions (+16 %) and cumulative VSSI (+86 %) compared to the past 2,500 years. This increase coincides with the rapid retreat of ice sheets during deglaciation, providing context for potential future increases of volcanic activity in regions under projected glacier melting in the 21st century. The reconstructed VSSI and SAOD data are available at https://doi.pangaea.de/10.1594/PANGAEA.928646 (Sigl et al., 2021).


Author(s):  
Hoan Hoang Van ◽  
Flemming Larsen ◽  
Nhan Pham Quy ◽  
Long Tran Vu ◽  
Giang Nguyen Thị Thanh

In Nam Dinh province, in the Red River delta plain in Northern Vietnam, groundwater in the shallow Holocene aquifer shows elevated total dissolved solids up to 35 km from the coastline, indicating a saltwater intrusion from the Gulf of Tonkin. High groundwater salinities have been encountered below and adjacent to the Red River in the deep Pleistocene aquifer. Since 1996, large-scale groundwater abstraction was initiated from the deep aquifer, and the observed elevated salinities now raise concerns about whether the groundwater abstraction is undertaken sustainably. We have conducted a study to obtain a fundamental understanding of the recharge mechanisms and salinization processes in the Nam Dinh province. A holistic approach with multiple methods including transient electromagnetic sounding and borehole logging, exploratory drilling, sampling and analyzing primary ion and stable isotope compositions of water and pore water, groundwater head monitoring, hydraulic experiments laboratory of clay layers, and groundwater modeling by using the SEAWAT code. Results reveal that saline river water is leached from the Red River and its distributaries into the shallow aquifers. The distribution and occurrence of salty pore water in the Holocene aquitard clay shows that meteoric water has not been flowing through these low permeable clay layers. Marine pore water has, however, been leached out of the Pleistocene clay. When this layer is present, it offers protection of the lower aquifer against high salinity water from above. Salinity as high as 80 % of oceanic water is observed in interstitial pore water of the transgressive Holocene clay. Saltwater is transported into the Pleistocene aquifer, where the Holocene clay is directly overlying the aquifer.


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