Biomass and fossil-fuel combustion history in the Osaka Plain, based on charcoal and spheroidal carbonaceous particles(SCPs) records of the latest Pleistocene and Holocene sediments

自然和人为的燃烧过程调动了大量与环境有关的物质。本文研究了日本中部大阪平原最新更新世和全新世沉积物中的宏观和微观木炭颗粒以及球形碳质颗粒(SCP)。木炭颗粒是通过生物质燃烧产生的。SCPS是化石燃料不完全高温燃烧形成的产物，根据最新更新世和全新世沉积的木炭地层，将晚12ka划分为12ka~9ka、9ka~2ka和2ka以来三个时期。木炭丰度从12ka左右开始增加，11ka~9ka之间木炭丰度最高，与远古人类活动有关。9ka以后，木炭丰度逐渐降低，从2ka到现在逐渐增加。因此，沉积物中木炭丰度的证据表明，大阪平原生物质火灾频率的变化受到古代人类活动的影响，最新的全新世沉积物中SCPs的浓度在20世纪30年代初有所增加。此后，SCPs的浓度在20世纪50年代迅速上升，从70年代到现在下降。这些趋势可以分别归因于工业活动的增长和大气污染物排放的调节。

Natural and anthropogenic combustion processes mobilize a large variety of materials about the environment. In this study, macroscopic and microscopic charcoal particles, and spheroidal carbonaceous particles (SCPs) in the latest Pleistocene and Holocene sediments of the Osaka Plain, central Japan, were studied. Charcoal particles are generated through biomass burning. SCPs are formed from incomplete high temperature combustion of fossil fuels.Based on the charcoal stratigraphy of the latest Pleistocene and Holocene sediments, the last 12ka is divided into three periods : 12 ka to 9 ka, 9 ka to 2 ka and since 2 ka. Charcoal abundance increased from about 12 ka, and the highest abundance of charcoal between 11 ka and 9 ka was associated with the ancient human activities. After 9ka, charcoal abundance decreased and increased gradually from 2 ka to present. Conquently, charcoal abundance evidence in the sediments suggests that variation of biomass fire frequency in the Osaka Plain was affected by ancient human activities.SCPs concentration in the latest Holocene sediments increased in the early 1930s. After that SCPs concentration increased rapidly in 1950s and decreased from 1970s to present. These trends can ascribed to the growth of industial activities and the regulation of atomospheric pollutant emission, respectively.