对湖光岩玛珥湖沉积物全新世粒度参数、550℃烧失量和Ti元素含量的变化特征研究后认为:粒度频率特征曲线指示湖光岩玛珥湖沉积物的外源输入部分主要来自其小流域;沉积物粒径的变化主要受降雨量,而不是湖泊水位波动的控制;较粗的粒径指示降雨量增加,较细的粒径指示降雨量降低.湛江地区全新世早期季风强盛,6085 a B.P.以后,季风显著减弱.湖光岩沉积物记录的全新世中期季风迅速减弱的发生时间与全球很多地质载体记录的全新世中期季风迅速减弱时间都非常接近,体现了湛江地区全新世季风演化的全球性.湛江地区6085 a B.P.以后的季风迅速减弱、气候转干很可能与厄尔尼诺活动增强有关. 2000 a B.P.以后,粒度参数、550℃烧失量和Ti元素含量的变幅明显增加与人类活动的影响有关,是人类活动和气候因素共同作用的结果.
英文摘要:
Through investigation on grain size parameters,loss on ignition (550℃) and Ti contents of Huguangyan Maar Lake sediment during the Holocene,frequency curve of grain size suggests that terrestrial input of Huguangyan Maar Lake are predominantly from its small catchment,and grain size variation of the sediment during the Holocene was determined by precipitation instead of lake level fluctuation,with coarser grain size indicating higher precipitation and finer grain size indicating lower precipitation. Asian monsoon at Zhanjiang area was strong in the early Holocene,and weakened substantially since 6085 a B.P.. The substantial weakening of Asian monsoon in the mid-Holocene recorded by Huguangyan Maar Lake sediment occurred at the time which was very close to the time of substantially weakened monsoon event recorded by many other archives around the globe,embodying globalization of monsoon evolution during the Holocene of Zhanjiang area. Weakened Asian monsoon and enhanced drought since 6085 a B. P. might be related to the enhanced ENSO activity. The amplitude of grain size parameters,loss on ignition (550℃) and Ti content increased remarkably after 2000 a B.P.,which may be due to intensified human activity and it is the result of both human activities and climate change.