摘要: 米兰科维奇旋回理论是古环境研究中重要的时间“度量”工具。文中以贵州普安糯东17号煤层和云南富源天佑10号煤层为例,对晚二叠世煤层的地球物理测井信号进行频谱分析,以获得其中的米兰科维奇轨道周期参数。研究发现,测井信号所反映出的煤层灰分含量变化受泥炭地发育时期的米兰科维奇轨道周期(123 ka(偏心率):35.6 ka(斜率):21.2 ka(岁差))驱动。以煤层剖面中的轨道周期为时间尺度,进一步计算出晚二叠世泥炭地的碳聚集速率为54.3~77.0 gC/(m2·a),对应的净初级生产力(NPP)为543~1540 gC/(m2·a)。 基于晚二叠世、晚石炭世和现代热带泥炭地的NPP与各个时期大气成分的对比结果显示,大气中的二氧化碳和氧气含量对陆相生态系统的净初级生产力具有关键性的控制作用。
关键词:
米兰科维奇旋回,
晚二叠世,
泥炭地,
碳聚集速率,
净初级生产力
Abstract: Milankovitch theory is an important tool in constraining time in the palaeoenviorment analysis. In this study,the geophysical logs of the Late Permian No.17 Coal in Nuodong,Puan of Guizhou Province and No.10 Coal in Tianyou,Fuyuan of Yunnan Province are analyzed employing spectral analysis.The result shows that the mineral matter content(ash yield)of the coal was possibly influenced by 123ka(eccentricity),35.6 ka(obliquity)and 21.2 ka(precession)Milankovitch cycles.Using this timeframe,the Lopingian tropical peatland carbon accumulation rate is calculated to be 54.3~77.0 gC/(m2·a),which is expected to correspond to a NPP of 543~1540 gC/(m2·a). A comparison of NPP and temporal atmospheric composition among the Late Permian,Late Carboniferous and modern time indicates that the Late Permian NPP calculated is consistent with geochemical and palaeobotanical models,supporting a proposal that terrestrial productivity is mainly controlled by temporal atmospheric O2 and CO2 levels.
Key words:
Milankovitch cycle,
Late Permian,
peatland,
carbon accumulation rate,
net primary productivity(NPP)
中图分类号:
邵龙义, 汪 浩, Large D J. 中国西南地区晚二叠世泥炭地净初级生产力及其控制因素*[J]. 古地理学报, 2011, 13(5): 473-480.
Shao Longyi, Wang Hao, Large D J. Net primary productivity and its control of the Late Permian peatlands in southwestern China[J]. JOURNAL OF PALAEOGEOGRAPHY, 2011, 13(5): 473-480.