中文摘要：

文章对新疆孔雀河北缘的西大沟剖面中更新世湖相沉积物开展ESR测年和孢粉记录研究。结果显示,该剖面湖相沉积自730kaB.P.延续到360kaB.P.。这一期间,研究区为落叶阔叶林植被,林下生长灌木和草本,低洼潮湿的地方生长蕨类孢子和藻类。植被的主要类型有栗（Castanea）、栎（Quercus）、松（Pinus）、柏（Cupressaceae）、蒿（Artemisia）、藜（Chenopodiaceae）、莎草（Cyperaceae）等,同时还含有少量的山核桃（Carya）、枫香（Liquidambar）及枫杨（Pterocarya）等亚热带孑遗植物花粉。这与前人研究发现中更新世研究区发育大湖的认识颇为一致。具体来说,组合带A（730-640kaB.P.）,C（595-505kaB.P.）和E（440-385kaB.P.）阔叶树花粉含量高,而灌木和草本花粉含量低; 组合带B（640-595kaB.P.）,D（505-440kaB.P.）和F（385-350kaB.P.）阔叶树花粉含量低,而灌木和草本花粉含量高,揭示中更新世研究区气候总体上呈现冷干-暖湿的气候波动特征。这一气候变化特征和模式与甘肃白水剖面多种风化指标揭示的相应时段风化强度波动可以对比,与全球深海氧同位素记录以及海平面波动也可以对比。不过,这一气候变化规律的内部驱动机制还有待进一步深入研究。

英文摘要：

In this study,a 4.5-m-thick section of lake sediments（89°53＇N,40°41＇E）was discovered in the northern margin of the Peacock River in Northwestern China.It is located at Xidagou,Tarim town,Yuli county,eastern Xinjiang Province.From up to bottom,four Electron Spin Resonance（ESR）ages were achieved,435±43kaB.P.at 1.0m,473±47kaB.P.at 1.5m,636±63kaB.P.at 3.2m,and 691±69kaB.P.at 4.2m.These suggest that this section spans a mid-Pleistocene interval of 730-360kaB.P.and establishes a reliable chronological framework for the Xidagou section.In the meanwhile,18 pollen samples were analyzed and 5107 grains of pollen and spores were identified（mean 284 grains/sample）.A total of 66 spore and pollen types were identified.On the whole,arboreal pollen taxa were dominant in most of the samples,ranging from 54.1% to 65.8% in abundance with an average of 58.6% .Shrubs and herbs were less dominant,fluctuating between 20.2% to 30.3% in abundance and averaging to 23.2% .Fern spores and algae ranged from 11.9% to 22.6% in content and had a mean of 17.2% .These indicate that,during the deposition of this section,the study area was generally covered continuously by broadleaved forests,under which various shrubs and herbs grew vigorously.Ferns and algae mainly distributed in some low-lying humid places within the study area.Main taxa included Castanea,Quercus,Pinus,Cupressaceae,Artemisia,Chenopodiaceae,Cyperaceae,etc.Also present were Carya,Liquidambar and Pterocarya,and these subtropical types occurred commonly with low and erratic percentages.The presence of these taxa and their content variations were well consistent with development of a big lake in the study region during the mid-Pleistocene inferred from previous studies.Specifically,in zones A（730-640kaB.P.）,C（595-505kaB.P.）and E（440-385kaB.P.）,the broadleaved arboreal pollen was always high in abundance while the shrub and herb pollen was usually low.In zones B（640-595kaB.P.）,D（505-440kaB.P.）and F（385-350kaB.P.）,the broadleaved tree polle