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Combustion-derived and land-plant-derived polycyclic aromatic hydrocarbons (PAHs) have been investigated by using the GC-MS analysis in an ancient soil profile from Jinluojia (金罗家) archaeological site at Macheng (麻城),Hubei (湖北) Province,Central China.Retene,cadalene and simonellite were proposed to be derived from contemporary land plants.The pyrolytic PAHs identified include fluoranthene,pyrene,benzofluoranthenes,benzo[e]pyrene and benzo[a]pyrene.The distribution of these pyrolytic PAHs varies with depth,displaying a pattern different from the land-plant-derived compounds.On the basis of the parameter diagnostic of sources and the distribution patterns,these pyrolytic PAHs were demonstrated to be of combustion origin,rather than petrogenic origins,combustion of petroleum products and coal,or a post-depositional process such as pedogenesis or leaching.These combustion-induced PAHs were believed to result from both natural processes and anthropogenic activities.Two episodes of the elevated content of pyrolytic PAHs and charcoal fragments were identified in Ming-Qing (明清) Dynasty and late Xizhou (西周) to early Dongzhou (东周) Dynasty,inferring the occurrence of two enhanced paleofires.The two enhanced paleofire episodes were found in association with the two cold and dry paleoclimate and two episodes of enhanced abundance of charcoal fragments,inferring a dominance of the natural processes triggering the enhanced paleofire.The two periods of paleofire were also characterized by the frequent and enhanced anthropogenic activities such as war fights,likely suggesting the occurrence of anthropogenic contributions.
Combustion-derived and land-plant-derived polycyclic aromatic hydrocarbons (PAHs) have been investigated by using the GC-MS analysis in an ancient soil profile from Jinluojia archaeological site at Macheng (Macheng), Hubei , Central China.Retene, cadalene and simonellite were proposed to be derived from contemporary land plants. The pyrolytic PAHs identified include fluoranthene, pyrene, benzofluoranthenes, benzo [e] pyrene and benzo [a] pyrene.The distribution of these pyrolytic PAHs varies with depth, displaying a pattern different from the land-plant-derived compounds. On the basis of the parameter diagnostic of sources and the distribution patterns, these pyrolytic PAHs were demonstrated to be of combustion origin, rather than petrogenic origins, combustion of petroleum products and coal, or a post-depositional process such as pedogenesis or leaching. these combustion-induced PAHs were believed to result from both natural processes and anthropogenic activities. Two episodes s of the elevated content of pyrolytic PAHs and charcoal fragments were identified in Ming-Qing Dynasty and late Xizhou to early Dongzhou Dynasty, inferring the occurrence of two enhanced paleofires episodes were two found in association with the two cold and dry paleoclimate and two episodes of enhanced abundance of charcoal fragments, inferring a dominance of the natural processes triggering the enhanced paleofire. The two periods of paleofire were also characterized by the frequent and enhanced anthropogenic activities such as war fights, likely suggesting the occurrence of anthropogenic contributions.