Through coring without disturbing in lacuster of Angulinao L ak e, making thin sections with the core and observing under scanning electron micr oscope, annual lamina caused by winter monsoon is discovered. It’s the ...Through coring without disturbing in lacuster of Angulinao L ak e, making thin sections with the core and observing under scanning electron micr oscope, annual lamina caused by winter monsoon is discovered. It’s the first rep ort on annual lamina in lake in semi-arid district which caused by monsoon.The lamina can play an important role in the research on sedimentology and environme nt evolution.展开更多
北大西洋地区是全球环境变化研究的热点区域。对IODP(国际综合大洋钻探计划)北大西洋306航次U1313站位深海沉积物陆源组分的粒度分析发现,陆源组分主要由黏土(粒径小于4μm)和极细粉沙(4~8μm)两个粒级构成,以黏土为主,分选性较差。通...北大西洋地区是全球环境变化研究的热点区域。对IODP(国际综合大洋钻探计划)北大西洋306航次U1313站位深海沉积物陆源组分的粒度分析发现,陆源组分主要由黏土(粒径小于4μm)和极细粉沙(4~8μm)两个粒级构成,以黏土为主,分选性较差。通过与钙质超微化石、有孔虫等生物化石资料和同位素测年等技术相结合,重建了古气候的变化情况:(1)2.415~1.897 Ma BP,气候呈周期性波动;(2)1.897~1.640 Ma BP,气候变化相对平缓;(3)1.640~1.471 Ma BP,气候波动剧烈且频繁。粒度指标所反映的几次粗颗粒增多事件与早更新世期间数次气候变冷事件的发生时间一致。1.6 Ma BP前后粒度参数的突然变化,可能与地球轨道参数的改变有关,进一步证实地球轨道参数作为气候系统外部驱动力的重要性。展开更多
文摘Through coring without disturbing in lacuster of Angulinao L ak e, making thin sections with the core and observing under scanning electron micr oscope, annual lamina caused by winter monsoon is discovered. It’s the first rep ort on annual lamina in lake in semi-arid district which caused by monsoon.The lamina can play an important role in the research on sedimentology and environme nt evolution.
文摘北大西洋地区是全球环境变化研究的热点区域。对IODP(国际综合大洋钻探计划)北大西洋306航次U1313站位深海沉积物陆源组分的粒度分析发现,陆源组分主要由黏土(粒径小于4μm)和极细粉沙(4~8μm)两个粒级构成,以黏土为主,分选性较差。通过与钙质超微化石、有孔虫等生物化石资料和同位素测年等技术相结合,重建了古气候的变化情况:(1)2.415~1.897 Ma BP,气候呈周期性波动;(2)1.897~1.640 Ma BP,气候变化相对平缓;(3)1.640~1.471 Ma BP,气候波动剧烈且频繁。粒度指标所反映的几次粗颗粒增多事件与早更新世期间数次气候变冷事件的发生时间一致。1.6 Ma BP前后粒度参数的突然变化,可能与地球轨道参数的改变有关,进一步证实地球轨道参数作为气候系统外部驱动力的重要性。