理县黄土地层与环境记录

LOESS STRATIGRAPHY AND ENVIRONMENT RECORDS IN LIXIAN COUNTY,SICHUAN PROVINCE

  • 摘要: 理县黄土堆积厚度为7.30 m,可分为S0、S1古土壤层和L1黄土层。光释光结果显示,理县黄土沉积始于末次间冰期,约130 kaBP。磁化率、粒度、碳酸盐含量等经典气候替代指标分析表明,它们可以反映青藏高原东部气候环境变迁。环境记录显示,末次冰期间冰阶(即氧同位素3阶段)期间该区呈现出极端冷湿的气候环境。理县地区气候演化更接近于印度季风强度记录的变化,而与格陵兰冰心和深海氧同位素记录相似性稍差。

     

    Abstract: The loess accumulation consists of paleosol S0 and S1 and loess L1 in Lixian County,Sichuan Province,whose thickness is 7.30 m.According to OSL dating results,geological survey and magnetic susceptibility characters,the loess accumulation originated from the last glaciation since 130 kaBP.Through some analyses of classical climatic substitute indexes such as magnetic susceptibility,grain size and CaCO3 content,it is revealed that they can still reflect the environmental and climatic changes in the east of Qinghai-Tibet Plateau.Environmental records show that in that area the environment was extremely cold and wet during the interstage of the last glaciation(deep sea oxygen isotope stage 3).The environmental variations in Lixian County are close to Indian monsoon records in intensity changes,but its similarity to the Greenland Ice Core and deep-sea oxygen isotope records is slightly lower.

     

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