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Hebei Normal University (2019)

The Preferred Application of Environmental Proxies of Tamarix Cone in Environmental Change Research in the Southern Source of the Taklimakan Desert

张硕;

Titre : The Preferred Application of Environmental Proxies of Tamarix Cone in Environmental Change Research in the Southern Source of the Taklimakan Desert

Auteur : 张硕;

Grade : Master’s Theses 2019

Université : Hebei Normal University

Résumé partiel
The Taklimakan Desert is located in the southern part of Xinjiang Uygur Autonomous Region.It has the Pamir Plateau in the west,the Lop Nur in the east,the Tianshan Mountain in the north,the Altun Mountains,the Kunlun Mountains and the Qinghai-Tibet Plateau in the south.The terrain is high in the southwest and low in the northeast.It is surrounded by mountains on three sides.The center of the Eurasian continent is far from the ocean,making it the most arid region in Asia.The southern source of the Taklimakan Desert has many oases and is the core of the arid region.Studying the environmental changes in the southern source of the Taklimakan Desert is important for studying the environmental changes in the arid region,but the lack of traditional information carriers due to environmental changes limits the study of environmental changes in the region.Tamarix sediment veins formed by alternating deposition of litter layers and sand layers,just like the annual rings of trees,it is a high-resolution dating method,and it also contains rich information on paleoclimate environment,which has become an effective means of studying environmental evolution in arid regions.This paper takes Minfeng County and Cele County in the southern source of the Taklimakan Desert as the research area,and takes the typical Tamarix sediment veins in the three areas of Andir,the Andir Ranch and Damagou Town as the research object,and analyzes and processes the field survey and laboratory experimentsasthe research method,Comprehensive optimization and analysis of sand grain-size,the organic matter carbon and nitrogen,positive ion content in Tamarix fallen leaves,stable carbon isotope and stable oxygen isotope contained in the Tamarix sediment veins.Establish a correlation between climate environmental indicators and meteorological data,using the stepwise regression method,the sequence of climate change in the southern source of the Taklimakan Desert has been reconstructed for hundreds of years,and compared with single indicator reconstruction result,related area research result,and standardized sequence research result,the sequence of climate environment change in the southern source of the Taklimakan Desert is obtained.The main conclusions are :(1)The litter layers and sand layers responded positively to environmental changes.The correlation between climate proxy index and annual average temperature is summarized as follows:standard deviation>kurtosis>sorting coefficient>skewness>Mg2+>K+>mean grain size>△δ13C>median particle size>Na+>C/N>TN>TOC>Ca2+>δ18O ;sand grain-size、positive ion content in Tamarix fallen leaves and△δ13C are sensitive ;The annual mean temperature and standard deviation,kurtosis,Mg2+and K+were all tested by confidence

Mots clés : environmental change; Tamarix cone; regression analysis; climate reconstruction; south region of Taklimakan Desert;

Présentation (CNKI)

Page publiée le 16 novembre 2019