scholarly journals Paleoflood records within Sikhote-Alin foothills during last 2.2 ka

Author(s):  
N. G. Razzhigaeva ◽  
L. A. Ganzey ◽  
T. A. Grebennikova ◽  
T. A. Kopoteva ◽  
M. A. Klimin ◽  
...  

The periods of intensification of the frequency of severe floods in Late Holocene were reconstructed on the basis of a multi-proxy study of the section of paleo-bend deposits in the lower reaches of the Bikin River, which includes a peat bog, buried by floodplain loam. The peat bog was formed on the place of flood lake and is represented by interlayering of the layers with a different contents of mineral components, which brought during heavy floods. The criteria for the allocation of phases of abundant river flow were defined. Peat ash content, biostratigraphic data (diatom, botanical analyzes) and radiocarbon dates of the peat bog showed that the flood activity in the foothills of the Sikhote-Alin changed significantly over the last 2.24 ka. The most severe floods occurred in the Medieval Warm Period and warm phases of the Little Ice Age. Duration of periods with strong floods varied from 70 to 200 years. Synoptic situations leading to heavy rainfall were probably similar to modern ones. Strong floods began last 210 yr in the conditions of a trend for warming. Reduction of flood activity, as a rule, occurred in cooling. The intensification of fires took place in drier periods. The response of swamp landscapes to the passage of severe floods and fires has been established.

1984 ◽  
Vol 21 (3) ◽  
pp. 275-285 ◽  
Author(s):  
H.E. Wright

Small ice fields on the western cordillera northeast of Lima were expanded to three times their present size in the recent past, and the regional snow line was probably about 100 m lower than it is today. Outwash from the expanded glaciers formed deltas of silt in valley-bottom lakes. When the ice lobes retreated, the reduced outwash was trapped behind recessional moraines, and the clear meltwater infiltrated into the limestone bedrock and emerged at the heads of the deltas in spring pools. The delta surfaces then became covered with peat, and radiocarbon dates for the base of the peat (1100 ± 70 and 430 ± 70 yr B.P. for two different deltas) indicate that the maximum ice advance was older than those dates and, thus, older than the Little Ice Age of many north-temperate regions. Much older moraines date from expansion of the same local summit glaciers to even lower levels in the main valleys, which had previously been inundated by the cordilleran ice field. The cordilleran deglaciation and this expansion of local glaciers probably occurred between 12,000 and 10,000 yr ago, on the basis of slightly contradictory radiocarbon dates.


2021 ◽  
Vol 5 (3) ◽  
pp. 287-304
Author(s):  
N.G. Razjigaeva ◽  
◽  
L.A. Ganzey ◽  
T.A. Grebennikova ◽  
T.A. Kopoteva ◽  
...  

The stages of development of small Solontsovskie (Shanduyskie) Lakes located in the middle mountains of the Central Sikhote-Alin within large landslides, formed on the slopes of the paleovolcano, are identified on the basis of complex study of the sediment section of the Nizhnee Lake. The ecological-taxonomic composition of the diatom flora, the botanical composition of peat have been analyzed, and the tendencies of lacustrine sedimentation depending on the different scale of hydroclimatic changes in the Late Holocene have been established. The age model is based on 6 radiocarbon dates. The temporary resolution for the reconstructions is 30–60 years. A comparison of the development of Nizhnee and Izyubrinye Solontsi Lakes was carried out, the stages of watering and shallowing of lakes were identified on the basis of their dynamics, which made it possible to restore the change in moisture in the middle mountains. Organogenic deposits in lacustrine basins accumulated at high rates (up to 1.7–1.9 mm/ year). The most detailed data were obtained for the last 2.6 thousand cal. yr BP based on the study of the sediment section of the Nizhnee Lake, which responded more sensitively to changing climatic conditions. Frequent changes in diatom assemblages and peat-forming plants indicate unstable hydroclimatic conditions with varying degrees of watering and drainage up to complete overgrowth of water bodies. According to the data of diatom analysis, a successive change in the trophicity of the lake was traced. A frequent change of sphagnum mosses of different sections with different trophic preferences was established. The main reason for the change in the hydrological regime of the lakes was variations in precipitation during the short-term climatic changes. The correlation of the identified paleoclimatic events with global data has been carried out. Cooling periods, as a rule, were accompanied by a decrease in moisture, but the Little Ice Age was wet due to an increase in precipitation.


The Holocene ◽  
2009 ◽  
Vol 19 (4) ◽  
pp. 625-637 ◽  
Author(s):  
François De Vleeschouwer ◽  
Natalia Piotrowska ◽  
Jarosław Sikorski ◽  
Jacek Pawlyta ◽  
Andriy Cheburkin ◽  
...  

The Holocene ◽  
2017 ◽  
Vol 27 (9) ◽  
pp. 1350-1358 ◽  
Author(s):  
Andrew P Moran ◽  
Susan Ivy Ochs ◽  
Marcus Christl ◽  
Hanns Kerschner

A two-phased moraine system in the high Alpine valley of Lisenser Längental in the Stubai Alps of western Austria is located in an intermediate morphostratigraphic position constrained by ‘Egesen Stadial’ (Younger Dryas) moraines down valley and ‘Little Ice Age’ (‘LIA’) positions (modern times) up valley. The equilibrium line altitude (ELA) was about 50 m lower than during the ‘LIA’ when applying an accumulation area ratio of 0.67. Exposure dating of boulders with 10Be yields a mean age of 3750 ± 330 years for the more extensive outer moraine system and a single age of 3140 ± 280 years for the inner one. The ages correspond well to the ‘Loebben oscillation’, a sequence of multi-decadal to multi-centennial cooling phases at the onset of the late-Holocene, also recognized in other Alpine records. The climatic downturn was severe enough to cause small to medium-sized Alpine glaciers in the central Alps to advance significantly beyond their ‘LIA’ extent, but too short to trigger a similar reaction with large glaciers.


Polar Record ◽  
2008 ◽  
Vol 44 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Naja Mikkelsen ◽  
Antoon Kuijpers ◽  
Jette Arneborg

ABSTRACTNorse immigrants from Europe settled in southern Greenland in around AD 985 and managed to create a farming community during the Medieval Warm Period. The Norse vanished after approximately 500 years of existence in Greenland leaving no documentary evidence concerning why their culture foundered. The flooding of fertile grassland caused by late Holocene sea-level changes may be one of the factors that affected the Norse community. Holocene sea-level changes in Greenland are closely connected with the isostatic response of the Earth's crust to the behaviour of the Greenlandic ice sheet. An early Holocene regressive phase in south and west Greenland was reversed during the middle Holocene, and evidence is found for transgression and drowning of early-middle Holocene coast lines. This drowning started between 8 and 7ka BP in southern Greenland and continued during the Norse era to the present. An average late Holocene sea level rise in the order of 2–3 m/1000 years may be one of the factors that negatively affected the life of the Norse Greenlanders, and combined with other both socio-economic and environmental problems, such as increasing wind and sea ice expansion at the transition to the Little Ice Age, may eventually have led to the end of the Norse culture in Greenland.


1986 ◽  
Vol 26 (1) ◽  
pp. 27-48 ◽  
Author(s):  
Stephen C. Porter

Time series depicting mountain glacier fluctuations in the Alps display generally similar patterns over the last two centuries, as do chronologies of glacier variations for the same interval from elsewhere in the Northern Hemisphere. Episodes of glacier advance consistently are associated with intervals of high average volcanic aerosol production, as inferred from acidity variations in a Greenland ice core. Advances occur whenever acidity levels rise sharply from background values to reach concentrations ≥1.2 μequiv H+/kg above background. A phase lag of about 10–15 yr, equivalent to reported response lags of Alpine glacier termini, separates the beginning of acidity increases from the beginning of subsequent ice advances. A similar relationship, but based on limited and less-reliable historical data and on lichenometric ages, is found for the preceding 2 centuries. Calibrated radiocarbon dates related to advances of non-calving and non-surging glaciers during the earlier part of the Little Ice Age display a comparable consistent pattern. An interval of reduced acidity values between about 1090 and 1230 A.D. correlates with a time of inferred glacier contraction during the Medieval Optimum. The observed close relation between Noothern Hemisphere glacier fluctuations and variations in Greenland ice-core acidity suggests that sulfur-rich aerosols generated by volcanic eruptions are a primary forcing mechanism of glacier fluctuations, and therefore of climate, on a decadal scale. The amount of surface cooling attributable to individual large eruptions or to episodes of eruptions is simlar to the probable average temperature reduction during culminations of Little Ice Age alacier advances (ca. 0.5°–1.2°C), as inferred from depression of equilibrium-line altitudes.


Radiocarbon ◽  
2009 ◽  
Vol 51 (2) ◽  
pp. 529-535 ◽  
Author(s):  
Ai-feng Zhou ◽  
Fa-hu Chen ◽  
Zong-li Wang ◽  
Mei-lin Yang ◽  
Ming-rui Qiang ◽  
...  

Many lacustrine chronology records suffer from radiocarbon reservoir effects. A continuous, accurate varve chronology, in conjunction with accelerator mass spectrometry (AMS) 14C dating, was used to determine the age of lacustrine sediment and to quantify the past 14C reservoir effect in Sugan Lake (China). Reservoir age varied from 4340 to 2590 yr due to 14C-depleted water in the late Holocene. However, during the Little Ice Age (LIA), 14C reservoir age was relatively stable. According to this study, 14C reservoir age in the late Holocene may be driven by hydrological and climatic changes of this period. Therefore, special caution should be paid to the correction of the 14C reservoir effect by a unique 14C reservoir age in paleoclimatic and paleolimnological study of northwest China.


2010 ◽  
Vol 6 (5) ◽  
pp. 1655-1683 ◽  
Author(s):  
C. Martín-Puertas ◽  
F. Jiménez-Espejo ◽  
F. Martínez-Ruiz ◽  
V. Nieto-Moreno ◽  
M. Rodrigo ◽  
...  

Abstract. A combination of marine (Alboran Sea cores, ODP 976 and TTR 300 G) and terrestrial (Zoñar Lake, Andalucia, Spain) paleoclimate information using geochemical proxies provides a high resolution reconstruction of climate variability and human influence in southwestern Mediterranean region for the last 4000 years at inter-centennial resolution. Proxies respond to changes in precipitation rather than temperature alone. Our archive documents a succession of dry and wet periods coherent with the North Atlantic climate signal. Drier stages occurred prior to 2.7 cal ka BP, well-correlated with the global aridity crisis of the third-millennium BC, and during the Medieval Warm Period (1.4–0.7 cal ka BP). Wetter conditions prevailed from 2.7 to 1.4 cal ka BP and after the Medieval Warm Period and the onset of the Little Ice Age. Hydrological signatures during the Little Ice Age are highly variable but consistent with more humidity that the period before. Additionally, Pb anomalies in sediments at the end of Bronze Age suggest anthropogenic pollution earlier than the Roman Empire development in the Iberian Peninsula. The evolution of the climate in the study area during the Late Holocene confirms the see-saw pattern previously shown between eastern and western Mediterranean regions and suggests a higher influence of the North Atlantic dynamics in the western Mediterranean.


Author(s):  
Т.Р. Макарова

Изучение разреза торфяника в бассейне р. Большая Уссурка (Приморье) позволило выявить изменения увлажненности. Установлен период продолжительных засух, совпадавших с ослаблением летнего муссона. Несмотря на сухие условия проходили паводки, вызванные тайфунами или глубокими циклонами. Влажными были малый оптимум голоцена и малый ледниковый период, характеризовавшиеся усилением циклогенеза. Отмечены кратковременные флуктуации увлажнения, периоды с разной паводковой активностью. Study of the peat bog section in the river basin Bolshaya Ussurka (Primorye) made it possible to distinguish periods with different moisture. Period of prolonged droughts was established, coinciding with the weakening of the summer monsoon. Dry conditions did not exclude floods due to the passage of typhoons or deep cyclones. The low optimum of the Holocene and the Little Ice Age, characterized by increased cyclogenesis, were humid. Short-term fluctuations of moisture, periods with different flood activity were noted.


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