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通过对日本大沼湖沉积物样品总有机碳含量(TOC)及其稳定同位素、总氮含量(TN)和C/N值的测定,结合沉积岩芯火山灰和~(14)C年代,分析了大沼湖沉积物中有机质的来源,探讨了沉积物有机碳同位素的主要影响因素。结果表明:大沼湖沉积物中有机质主要来源于自生藻类,受陆源输入的影响较小;沉积物δ~(13)C值指示了夏季温度的变化。过去400年来,大沼湖地区存在1660~1730年和1780~1860年两个明显的冷期,与邻近地区冰芯、树轮和湖泊沉积物记录的冷期基本一致,分别对应于Maunder和Dalton太阳黑子极小期。
Based on the determination of total organic carbon (TOC) and its stable isotopes, total nitrogen (TN) and C / N of sediment samples from Lake Onuma in Japan and the combination of sedimentary core volcanic ash and ~ (14) C ages, The origin of organic matter in sediments and the main influencing factors of organic carbon isotopes in sediments are discussed. The results show that the organic matter in the sediments of the Lake Amon mainly comes from the authigenic algae, which is less affected by the input of terrestrial sources. The δ ~ (13) C value of the sediments indicates the change of summer temperature. Over the past 400 years, there were two distinct cold periods from 1660 to 1730 and from 1780 to 1860 in the Lake Agano region, which were basically the same as the cold periods recorded in the ice cores, tree rings and lake sediments in the adjacent areas, corresponding to Maunder and Dalton Sunspot minimal period.