VEGETATION EVOLUTION OF JINCAOTAN WETLAND IN THE PAMIR PLATEAU,XINJIANG DURING THE MIDDLE TO LATE HOLOCENE
Wetland fossil sediments contain a large amount of paleovegetation information and have been one of the critical fields of past global change research,especially wetland ecosystems located in arid and semi-arid regions,which are more sensitive to climate change due to their fragile ecological environment.In this paper,Jincaotan wetland in Tashkurgan County(35°37′～38°40′N,71 °20′～77°01 ′E),the Pamir Plateau of Xinjiang,was selected as the research area.Based on a chronological framework supported by AMS l4C data and fossil pollen data from the LGC profile(37°49′49.1″N,75° 12′58.4″E)of Jincaotan wetland,the vegetation change of Pamir Plateau in Xinjiang over the past 5300 years have been preliminarily discussed.The lithology of the LGC profile is mainly composed of silt.A total of 31 pollen samples were obtained from the 72 cm LGC profile.The pollen analysis showed that between 5300 cal.a B.P.and 3750 cal.a B.P.,wetland plants such as Cyperaceae and aquatic plants such as Urticularia had higher pollen content,indicating that the local environment of the Jincaotan wetland was relatively humid,and the aquatic plants were thriving since 3750 cal.a B.P.The environment also changed owing to several dry and wet fluctuations.From 3750～1840 cal.a B.P.,drought-tolerant Ephedra dominated,and Chenopodiaceae increased compared to the previous period,indicating that the local environment gradually changed from wet to dry,wetland area shrank,and regional vegetation eventually shifted from desert steppe to desert vegetation in the later stage.From 1840 cal.a B.P.to 810 cal.a B.P.,regional vegetation returned to desert steppe vegetation.Subsequently,the regional environment gradually deteriorated,and the surrounding area became a desert steppe landscape.Compared with other fossil records in Xinjiang,from 1170 cal.a B.P.to 730 cal.a B.P.period,the climate in this area was humid and equivalent to that of the Medieval Warm Period.In addition,Cedrus,Picea,and Pinus pollen contents were low in fossil sediments.This study provides a preliminary exploration of vegetation and environmental changes in the area over the past 5300 years to deepen our understanding of the local environmental changes.However,the selected profile has certain limitations regarding sediment resolution and dating data.Qualitative analysis and further utilization of high-resolution fossil records are needed to reveal the characteristics of regional environmental evolution in the area later.
万方数据
维普
