OSL chronology and possible forcing mechanisms of dune evolution in the Horqin dunefield in northern China since the Last Glacial Maximum

2012 ◽  
Vol 78 (2) ◽  
pp. 185-196 ◽  
Author(s):  
LinHai Yang ◽  
Tao Wang ◽  
Jie Zhou ◽  
ZhongPing Lai ◽  
Hao Long
Keyword(s):  
Last Glacial Maximum ◽  
Asian Monsoon ◽  
Northern China ◽  
Glacial Maximum ◽  
Last Glacial ◽  
Millennial Time Scale ◽  
Forcing Mechanisms ◽  
The Last Glacial Maximum ◽  
Multiple Episodes ◽  
The Last Glacial

AbstractThe evolution processes and forcing mechanisms of the Horqin dunefield in northern China are poorly understood. In this study, systematic OSL dating of multiple sites is used together with pollen analysis of a representative section in order to reconstruct the evolution of the dunefield since the Last Glacial Maximum (LGM). Our results show that there was extensive dune mobilization 25–10 ka, transition to stabilization 10–8 ka, considerable dune stabilization 8–3 ka, and multiple episodes of stabilization and mobilization after 3 ka. Comparison of dune evolution of the dunefields in northern China during the Holocene showed that Asian monsoon and resultant effective moisture have played an important role in the evolution of dunefields at the millennial time scale. Further analysis indicated that the dune evolution in the Horqin dunefield before 3 ka was synchronous with climatic changes. However, increasing human activity has impacted dune evolution during the last 3 ka.

The evolution of dry lands in northern China and in the Republic of Mongolia since the Last Glacial Maximum

2004 ◽  
Vol 118-119 ◽  
pp. 69-85 ◽  
Author(s):  
Xiaoping Yang ◽  
Karl Tilman Rost ◽  
Frank Lehmkuhl ◽  
Zhu Zhenda ◽  
John Dodson
Keyword(s):  
Last Glacial Maximum ◽  
Northern China ◽  
Glacial Maximum ◽  
Last Glacial ◽  
Dry Lands ◽  
The Republic ◽  
The Last Glacial Maximum ◽  
The Last Glacial

Asian monsoon climate during the Last Glacial Maximum: palaeo-data-model comparisons

Boreas ◽  
2013 ◽  
Vol 43 (1) ◽  
pp. 220-242 ◽  
Author(s):  
Akkaneewut Chabangborn ◽  
Jenny Brandefelt ◽  
Barbara Wohlfarth
Keyword(s):  
Last Glacial Maximum ◽  
Data Model ◽  
Asian Monsoon ◽  
Glacial Maximum ◽  
Monsoon Climate ◽  
Model Comparisons ◽  
Last Glacial ◽  
The Last Glacial Maximum ◽  
The Last Glacial

The paleoclimatic implication of oxygen isotopes of authigenic carbonates in loess on the Northeastern Tibetan Plateau since Last Glacial Maximum

2018 ◽  
Vol 42 (6) ◽  
pp. 826-840
Author(s):  
Quanxu Hu ◽  
Xianyan Wang ◽  
Shuangwen Yi ◽  
Xianqiang Meng ◽  
Hao Long ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Last Glacial Maximum ◽  
Asian Monsoon ◽  
Glacial Maximum ◽  
Early Holocene ◽  
Last Glacial ◽  
Northeastern Tibetan Plateau ◽  
Loess Deposits ◽  
The Last Glacial Maximum ◽  
The Last Glacial

As a significant component of the global climate system, the East Asian monsoon (EAM) is crucial in understanding general climate change. The response of sensitivity and extent of the EAM to orbital-timescale climate change remains controversial. The composition of oxygen isotopes of authigenic (pedogenic) carbonate in loess deposits from the Northeastern Tibetan Plateau was measured, which is at the modern northwestern boundary of the present-day EAM, and compared with equivalent data from northeastern China under the influence of the EAM and two selected sites in the zone under the influence of the westerlies (Bayanbulak (Xinjiang) and Kesselt (Belgium)). The data enable discussion of the paleoclimatic implication of δ18O of carbonate in loess deposits and extension (changes) of the EAM-affected area during the Last Glacial Maximum and early Holocene. The δ18O values of authigenic carbonate at the Northeastern Tibetan Plateau were close to those from the westerly climate zone, but higher than those from regions affected by the Asian monsoon during the Last Glacial Maximum and early Holocene. This indicates that precipitation moisture sources at the Northeastern Tibetan Plateau were likely not directly derived from the EAM during Last Glacial Maximum and early Holocene. In contrast, the westerlies and locally recycled or evaporated moisture were possibly the dominant influencing factors of the relatively δ18O-enriched soil water and the authigenic carbonate in Northeastern Tibetan Plateau. Further study of loess carbonate records from the Northeastern Tibetan Plateau will reveal the past climate changes in the plateau region and provide valuable clues for the interaction between the Asian monsoon and westerly climate systems.

Reconstructions of the past distribution of Testudo graeca mitochondrial lineages in the Middle East and Transcaucasia support multiple refugia since the Last Glacial Maximum

2021 ◽  
pp. 10-17
Author(s):  
Oguz Turkozan
Keyword(s):  
Middle East ◽  
Last Glacial Maximum ◽  
Glacial Maximum ◽  
Testudo Graeca ◽  
Last Glacial ◽  
The Past ◽  
Precipitation Seasonality ◽  
Multiple Refugia ◽  
The Last Glacial Maximum ◽  
The Last Glacial

A cycle of glacial and interglacial periods in the Quaternary caused species’ ranges to expand and contract in response to climatic and environmental changes. During interglacial periods, many species expanded their distribution ranges from refugia into higher elevations and latitudes. In the present work, we projected the responses of the five lineages of Testudo graeca in the Middle East and Transcaucasia as the climate shifted from the Last Glacial Maximum (LGM, Mid – Holocene), to the present. Under the past LGM and Mid-Holocene bioclimatic conditions, models predicted relatively more suitable habitats for some of the lineages. The most significant bioclimatic variables in predicting the present and past potential distribution of clades are the precipitation of the warmest quarter for T. g. armeniaca (95.8 %), precipitation seasonality for T. g. buxtoni (85.0 %), minimum temperature of the coldest month for T. g. ibera (75.4 %), precipitation of the coldest quarter for T. g. terrestris (34.1 %), and the mean temperature of the driest quarter for T. g. zarudyni (88.8 %). Since the LGM, we hypothesise that the ranges of lineages have either expanded (T. g. ibera), contracted (T. g. zarudnyi) or remained stable (T. g. terrestris), and for other two taxa (T. g. armeniaca and T. g. buxtoni) the pattern remains unclear. Our analysis predicts multiple refugia for Testudo during the LGM and supports previous hypotheses about high lineage richness in Anatolia resulting from secondary contact.

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