Vegetational and climatic significance of modern pollen rain in northwestern Tibet

Cour, P.; Zheng, Zhuo; Duzer, D.; Calleja, Michel; Zu-ju, Yao

doi:10.1016/s0034-6667(98)00062-1

Cited by 154 publications

(131 citation statements)

References 8 publications

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“…In the modern deserts of northwestern China, where these taxa presently occur, annual rainfalls of less than 100 mm are measured which makes these among the most arid regions in the world (Sun and Wang, 2005). Ephedra and Nitraria have slightly different ecological ranges; Ephedra prefers aridity (semi-desert) while Nitraria is a relatively more humid steppe/desert taxon (Xi and Sun, 1987;Cour et al, 1999;Sun and Wang, 2005;Jiang and Ding, 2008;Ma et al, 2008;Li et al, 2009;Zhao and Herzschuh, 2009). According to Li et al (2005) the Nitraria/Ephedra (N/E) ratio is below 1 in typical desert communities and above 1 in steppe-desert environments suggesting that the ratio of these taxa may be used as a measure of relative humidity in this dry environment.…”

Section: The Xerophytic Taxa: Nitraria/ephedra (N/e) Ratiomentioning

confidence: 99%

A late Eocene palynological record of climate change and Tibetan Plateau uplift (Xining Basin, China)

Hoorn

Straathof

Abels

et al. 2012

Palaeogeography, Palaeoclimatology, Palaeoecology

120

103

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General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Climate models suggest that Asian paleoenvironments, monsoons and continental aridification were primarily governed by tectonic uplift and sea retreat since the Eocene with potential contribution of global climate changes. However, the cause and timing of these paleoenvironmental changes remain poorly constrained. The recently well-dated continental mudflat to ephemeral saline lake sedimentary succession, situated in the Xining Basin at the northeastern margin of the Tibetan Plateau (NW China), provides a unique opportunity to develop additional proxy successions in this area that are placed accurately in time. Here, a palynological record from this succession is reported. High abundances of desert and steppe-desert taxa such as Ephedripites and Nitrariadites/Nitraripollis are found, which can be differentiated by the presence of broad leaved deciduous forest taxa in the lower part of the section (particularly up to 36.4 Ma; magnetochron C16r), and a sudden increase of Pinaceae (Pinuspollenites, Piceaepollenites and Abiespollenites) which is dated at 36.1 Ma (C16n.2n). Coexistence Approach (CoA) indicates that from 39.9 to 36.4 Ma (C17n.1n) regional climate was warm and wet, while from 36.4 to 33.5 Ma (C16n.2n-C13r) climate tends to be cooler and drier. The data indicate that paleoenvironmental and palynological changes on the NE part of the Tibetan Plateau resulted from a combination of long-term tectonic uplift forcing and long-and short-term climate changes. The increase of taxa such as Piceaepollenites and Abiespollenites indicates not only a cooling and drying trend prior to the Eocene/Oligocene (E/O) boundary, but also the existence of high altitude mountain habitats in the periphery of the Xining Basin. The sudden Pinaceae event correlates closely in time with a marked aridification step as viewed from the lithology of the Xining Basin that was linked to the sea retreat out of the Tarim Basin.

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Section: The Xerophytic Taxa: Nitraria/ephedra (N/e) Ratiomentioning

confidence: 99%

A late Eocene palynological record of climate change and Tibetan Plateau uplift (Xining Basin, China)

Hoorn

Straathof

Abels

et al. 2012

Palaeogeography, Palaeoclimatology, Palaeoecology

120

103

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“…The deciphering of fossil pollen data must be performed on the basis of the investigation of modern pollen assemblages. Numerous studies (e.g., Wright et al, 1967;Gaillard et al, 1992;Sugita, 1994;Cour et al, 1999;Davis, 2000;Shen et al, 2006;Ma et al, 2008;Zhao and Herzschuh, 2009;Herzschuh et al, 2010;Lu et al, 2011;Fall, 2012;Zheng et al, 2013;Tian et al, 2014) have been conducted to understand the relationship of modern pollen assemblages with contemporary vegetation and climate. Modern pollen assemblages are mainly collected from airborne pollen collectors (e.g., Cour et al…”

mentioning

confidence: 99%

“…Numerous studies (e.g., Wright et al, 1967;Gaillard et al, 1992;Sugita, 1994;Cour et al, 1999;Davis, 2000;Shen et al, 2006;Ma et al, 2008;Zhao and Herzschuh, 2009;Herzschuh et al, 2010;Lu et al, 2011;Fall, 2012;Zheng et al, 2013;Tian et al, 2014) have been conducted to understand the relationship of modern pollen assemblages with contemporary vegetation and climate. Modern pollen assemblages are mainly collected from airborne pollen collectors (e.g., Cour et al, 1999;Giesecke et al, 2010), moss polsters (e.g., Hicks and Birks, 1996;Mazier et al, 2006), topsoils (e.g., Xu et al, 2009;Zhang et al, 2010) and surface lake sediments (e.g., Herzschuh, 2007;Seppa et al, 2004). However, the four types of pollen traps always yield different pollen assemblages even if they are collected from the same site (e.g., Fall, 1992;Wilmshurt and McGlone, 2005a;Lisitsyna et al, 2012;).…”

mentioning

confidence: 99%

Modern pollen assemblages from surface lake sediments in northwestern China and their importance as indicators of vegetation and climate

Feng

Zhao

et al. 2015

Sci. China Earth Sci.

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The modern pollen assemblages of surface lake sediments and topsoils in northwestern China were studied to understand the relationship of modern pollen data with contemporary vegetation and climate, and the differences between the pollen assemblages of surface lake sediments and topsoils. The results show that Chenopodiaceae and Artemisia are dominant elements in the pollen assemblages of northwestern China. Additionally, Ephedra, Cyperaceae, Asteraceae, Poaceae, Picea, Pinus, and Betula are also important pollen taxa. Both pollen assemblages and principal component analysis indicate that pollen data from surface lake sediments and topsoils can be used to differentiate the main vegetation types of this region (desert, steppe, meadow and forest). However, differences exist between modern pollen assemblages of the two types of sediments due to the different relevant source areas of pollen and degrees of pollen preservation. For example, the larger relevant source area of surface lake sediment results in a higher abundance of Betula in pollen assemblage from surface lake sediment, whereas the tendency to disintegrate thin-walled pollen types in topsoil leads to a higher proportion of resistant pollen, such as Asteraceae. Linear regression analysis indicates that the Artemisia/Chenopodiaceae (A/C) ratio in pollen assemblages of surface lake sediments can be used to indicate humidity changes in the study area. However, the A/C ratio in topsoils should be used carefully. Our results suggest that pollen data from surface lake sediments would be better references for interpreting the fossil pollen assemblages of lake cores or lacustrine profiles. Pollen data have been used to unravel the vegetation succession and climatic changes of the past since the pioneering work of von Post in 1916(Davis, 2000. The deciphering of fossil pollen data must be performed on the basis of the investigation of modern pollen assemblages. Numerous studies (e.g., Wright et al., 1967;Gaillard et al., 1992;Sugita, 1994;Cour et al., 1999;Davis, 2000;Shen et al., 2006;Ma et al., 2008;Zhao and Herzschuh, 2009;Herzschuh et al., 2010;Lu et al., 2011;Fall, 2012;Zheng et al., 2013;Tian et al., 2014) have been conducted to understand the relationship of modern pollen assemblages with contemporary vegetation and climate. Modern pollen assemblages are mainly collected from airborne pollen collectors (e.g., Cour et al

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“…1). The predominant wind directions today are from the west and result from the Westerly Jet Stream (Yang et al, 2013) but these are affected by seasonal influences from southern monsoon currents (Cour et al, 1999). The principal factor determining the climatic regimes of the Tian Shan Mountains is the interaction between the southwestern branch of the Siberian anticyclonic circulation and cyclonic activity from the west (Aizen et al, 1997).…”

Section: Study Sitementioning

confidence: 99%

Ecology and subsistence at the Mesolithic and Bronze Age site of Aigyrzhal-2, Naryn valley, Kyrgyzstan

Matuzevičiūtė

Preece

Wang

et al. 2017

Quaternary International

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River valleys in the Tien Shan Mountains of Kyrgyzstan have served as corridors for human dispersal since the Palaeolithic but little information exists on the history of human occupation in this remote and inaccessible region. Here, we report the results of a multidisciplinary study of Airgyrzhal-2, a high elevation (2005 m) site in the Naryn valley in central Kyrgyzstan. Two main occupation horizons were recognized, the earliest belonging to the Mesolithic (12th millennium cal. BC) and a later one dating from the Bronze Age (first half of the 2nd millennium cal. BC). Land snail analyses from the two horizons yielded almost identical assemblages of species of dry, open environments. Archaeobotanical data, however, revealed marked differences. The greater representation of willow/poplar (Salix/Populus) in the charcoal from the Mesolithic suggests more focused activity along the river, which might have been closer to the site at this time. The occurrence of spruce (Picea) and other species in the Bronze Age charcoal indicates exploitation of resources from more distant upland locations. The occurrence of the remains of cereals, including both grains and chaff, provides unexpected evidence for both consumption and cultivation of wheat and barley at this high elevation during the Bronze Age.

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Vegetational and climatic significance of modern pollen rain in northwestern Tibet

Cited by 154 publications

References 8 publications

A late Eocene palynological record of climate change and Tibetan Plateau uplift (Xining Basin, China)

A late Eocene palynological record of climate change and Tibetan Plateau uplift (Xining Basin, China)

Modern pollen assemblages from surface lake sediments in northwestern China and their importance as indicators of vegetation and climate

Ecology and subsistence at the Mesolithic and Bronze Age site of Aigyrzhal-2, Naryn valley, Kyrgyzstan

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