Buried Late-Holocene Luvisols of the Oka and Moskva river floodplains and their anthropogenic evolution according to soil and pollen data

2016 ◽  
Vol 418 ◽  
pp. 37-48 ◽  
Author(s):  
A.L. Alexandrovskiy ◽  
E.G. Ershova ◽  
N.A. Krenke
Keyword(s):  
Late Holocene ◽  
Pollen Data ◽  
River Floodplains ◽  
Moskva River ◽  
Anthropogenic Evolution

scholarly journals Late Holocene plant and climate evolution at Lake Yoa, northern Chad: pollen data and climate simulations

2011 ◽  
Vol 7 (4) ◽  
pp. 1351-1362 ◽  
Author(s):  
A.-M. Lézine ◽  
W. Zheng ◽  
P. Braconnot ◽  
G. Krinner
Keyword(s):  
Late Holocene ◽  
Climate Changes ◽  
Direct Consequence ◽  
Atmospheric Model ◽  
Plant Distribution ◽  
Time Interval ◽  
Pollen Data ◽  
Tropical Plant ◽  
Climate Simulations ◽  
Dry Spell

Abstract. The discovery of groundwater-fed Lake Yoa (19.03° N, 20.31° E) in the hyperarid desert of northern Chad by the German research team ACACIA headed by S. Kröpelin provides a unique, continuous sedimentary sequence of late Holocene age available in the entire Saharan desert. Here we present pollen data and climate simulations using the LMDZ atmospheric model with a module representing the climatologically-relevant thermal and hydrological processes occurring above and beneath inland water surfaces to document past environmental and climate changes during the last 6000 cal yr BP. Special attention is paid to wind strength and direction, length and amplitude of the rainy season, and dry spell occurrence, all of which are of primary importance for plant distribution and pollen transport. In addition to climate changes and their impact on the natural environment, anthropogenic changes are also discussed. Two main features can be highlighted: (1) the shift from an earlier predominantly monsoonal climate regime to one dominated by northern Mediterranean fluxes that occurred after 4000 cal yr BP. The direct consequence of this was the establishment of the modern desert environment at Yoa at 2700 cal yr BP. (2) Changes in climate parameters (simulated rainfall amount and dry spell length) between 6 and 4000 cal yr BP were comparatively minor. However, changes in the seasonal distribution of precipitation during this time interval dramatically affected the vegetation composition and were at the origin of the retreat of tropical plant communities from Lake Yoa.

Influence of regional anthropogenic changes over Nile region on the climate system during the late Holocene (~2500 years before present)

2020 ◽  
Author(s):  
Ram Singh ◽  
Allegra N. LeGrande ◽  
Kostas Tsigaridis
Keyword(s):  
Late Holocene ◽  
Volcanic Eruptions ◽  
Climate System ◽  
Anthropogenic Factors ◽  
Nile River ◽  
Before Present ◽  
Anthropogenic Changes ◽  
River Floodplains ◽  
Spatial Coverage ◽  
The Impact

<p>The societal impacts of climate change during the late Holocene leads to regional anthropogenic changes over the Nile region floodplain and could have acted in tandem with natural factors like major volcanic eruptions on the regional climate system to magnify the local climatic impacts. This study aims to explore and investigate the sensitivity of climatic changes to the regional anthropogenic changes due to various factors over the Nile river floodplains during the late-Holocene (2.5K years before present). The GISS ModelE Earth system model will be used to simulate the various scenarios of regional increasing/decreasing river fraction, changes in vegetation type and cover, along with changes in land surface type against the no-changes scenario in absence of volcanic eruptions. The spatial coverage of the Nile river basin is estimated using the GIS shapefile based on elevation data from Shuttle Radar Topography Mission (SRTM) at 3 Arc-seconds (approx. 90-meter) horizontal resolution. The extent of flooding in the model grid (2.0°x2.5° in latitude and longitude) is estimated using the existing high-resolution (0.125°x0.125°) gridded topographic elevation information and mapped over the Nile river floodplains. This study also focuses on evaluating the NASA GISS ModelE for resolving the climate feedbacks and response on climate system due to anthropogenic changes and volcanic eruptions. It is also aimed to analyze and quantify the impact of various anthropogenic factors over the African monsoon system and rainfall over the region, which feeds the Nile River.</p>

Palaeovegetation and climate oscillation of western Odisha, India: A pollen data-based synthesis for the Mid-Late Holocene

2014 ◽  
Vol 325 ◽  
pp. 83-92 ◽  
Author(s):  
Swati Tripathi ◽  
Sadhan K. Basumatary ◽  
Veeru K. Singh ◽  
Samir K. Bera ◽  
Chandra M. Nautiyal ◽  
...  
Keyword(s):  
Late Holocene ◽  
Pollen Data ◽  
Climate Oscillation

Vegetation changes and associated climatic changes in the southern Altai Mountains within China during the Holocene

The Holocene ◽  
2016 ◽  
Vol 27 (5) ◽  
pp. 683-693 ◽  
Author(s):  
Zhaodong Feng ◽  
Aizhi Sun ◽  
Nurbayev Abdusalih ◽  
Min Ran ◽  
Alishir Kurban ◽  
...  
Keyword(s):  
Climatic Change ◽  
North Atlantic ◽  
Late Holocene ◽  
Mean Annual Precipitation ◽  
Mean Annual Temperature ◽  
Mountain Range ◽  
Altai Mountains ◽  
Pollen Data ◽  
The Holocene ◽  
The Pacific

The location of the Altai Mountains at the limits of both the Pacific and Atlantic influences implies that this mountain range is an important climatic boundary. Based on pollen data of 188 samples of a 390-cm core from Narenxia Peat in the southern Altai with a chronologic support of 11 accelerator mass spectrometry (AMS) dates, we reconstructed the Holocene climatic change at Narenxia Peat. The reconstruction revealed five stages of climatic change: a cold and dry latest deglacial (prior to ~11,500 cal. yr BP), a warm and wet early-Holocene (~11,500 to ~7000 cal. yr BP), a considerably cooled and dried middle Holocene (~7000 to ~4000 cal. yr BP), a resumed warm and wet late-Holocene (~4000 to ~1200 cal. yr BP), and a relatively cool and dry latest Holocene (past ~1200 years). The reconstructions of mean annual temperature (MAT) and mean annual precipitation (MAP) from Narenxia Peat well resemble the reconstructions of North Atlantic Oscillations (NAO) and El Niño–Southern Oscillations (ENSO). The resemblance implies that the Holocene millennial-scale changes in MAT and MAP in the Altai might have been causally associated with the variations in NAO and ENSO.

Paleogeography of the Sea of Azov region in the Late Holocene (reconstruction by diatom and pollen data from marine sediments)

2013 ◽  
Vol 284 ◽  
pp. 123-131 ◽  
Author(s):  
Gennady Matishov ◽  
Galina Kovaleva ◽  
Elena Novenko ◽  
Kristina Krasnorutskaya ◽  
Vladimir Pol'shin
Keyword(s):  
Marine Sediments ◽  
Late Holocene ◽  
Sea Of Azov ◽  
Pollen Data ◽  
The Sea Of Azov ◽  
Azov Region

scholarly journals Holocene Hydroclimate Variability and Vegetation Response in the Ethiopian Highlands (Lake Dendi)

2020 ◽  
Vol 8 ◽  
Author(s):  
Andrea Jaeschke ◽  
Matthias Thienemann ◽  
Enno Schefuß ◽  
Jonas Urban ◽  
Frank Schäbitz ◽  
...  
Keyword(s):  
Late Holocene ◽  
Anthropogenic Activity ◽  
Gradual Transition ◽  
Complex Nature ◽  
Pollen Data ◽  
Ethiopian Highlands ◽  
C Isotopes ◽  
Hydroclimate Variability ◽  
Plant Wax ◽  
Humid Period

Northern Africa’s past climate is characterized by a prolonged humid period known as the African Humid Period (AHP), giving origin to the “Green Sahara” and supporting human settlements into areas that are now desert. The spatial and temporal extent of climate change associated with the AHP is, however, subject to ongoing debate. Uncertainties arise from the complex nature of African climate, which is controlled by the strength and interactions of different monsoonal systems, resulting in meridional shifts in rainfall belts and zonal movements of the Congo Air Boundary. Here, we examine a ∼12,500-years record of hydroclimate variability from Lake Dendi located in the Ethiopian highlands based on a combination of plant-wax-specific hydrogen (δD) and carbon (δ13C) isotopes. In addition, pollen data from the same sediment core are used to investigate the response of the regional vegetation to changing climate. Our δD record indicates high precipitation during peak AHP (ca. 10 to 8 ka BP) followed by a gradual transition toward a drier late Holocene climate. Likewise, vegetation cover changed from predominant grassland toward an arid montane forest dominated by Juniperus and Podocarpus accompanied by a general reduction of understory grasses. This trend is corroborated by δ13C values pointing to an increased contribution of C3 plants during the mid-to late Holocene. Peak aridity occurred around 2 ka BP, followed by a return to a generally wetter climate possibly linked to enhanced Indian Ocean Monsoon strength. During the last millennium, increased anthropogenic activity, i.e., deforestation and agriculture is indicated by the pollen data, in agreement with intensified human impact recorded for the region. The magnitude of δD change (40‰) between peak wet conditions and late Holocene aridity is in line with other regional δD records of East Africa influenced by the CAB. The timing and pace of aridification parallels those of African and Indian monsoon records indicating a gradual response to local insolation change. Our new record combining plant-wax δD and δ13C values with pollen highlights the sensitive responses of the regional vegetation to precipitation changes in the Ethiopian highlands.

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