摘要
四川盆地中侏罗世是恐龙最为繁盛的时期,该时期的沙溪庙组中广泛分布有成土作用形成的钙质结核,对此钙质结核的碳、氧同位素组成进行分析,结果表明,钙质结核的δ18O值在-10.50‰～-7.783‰(PDB)之间,平均值为-9.34‰,δ13C值在-9.30‰～-5.07‰(PDB)之间,平均值为-7.06‰。钙质结核的δ13C值表明这一时期四川盆地的植被以C3植物类型为主;利用Cerling的模型,推测大气CO2的浓度(分压)在1 400 ppmV～2 800 ppmV之间。中侏罗世沙溪庙组钙质结核的碳同位素组成为重建恐龙生活时代的古生态环境提供了地球化学方面的资料。
Middle Jurassic is the most bloom ate nodules occur in the Shaximiao Formation bon and oxygen isotopic analysis of carbonate sis,type of vegetation and the partial pressure period of dinosaur and abundant pedogenic carbon of Middle Jurassic in the Sichuan basin. Stable car nodules have been carried out. Based on the analy of CO2 have been discussed in this paper. The oxy gen isotope compositions of these pedogenic carbonates range from-10. 50‰ to -7. 783‰ （PDB）,with an average of -9. 34‰ （PDB） and the carbon isotope compositions range from -9.30‰ to -5.07‰ （PDB）, with an average of -7.06‰, suggesting that carbonate formation in soils dominated by Ca type of vegetation. An analysis of these values using the estimation of the CO2 content of the palaeo-atmosphere by using Cerlingrs model indicates that the partial pressure of CO2 in the Middle Jurassic atmosphere was about 1 400 ppmV-2 800 ppmV. These geochemical data can be used to reconstruct the palaeogeography of dinosaur living period.
出处
《矿物岩石》
CAS
CSCD
北大核心
2007年第2期54-58,共5页
Mineralogy and Petrology
基金
中国地质调查局"四川盆地中生代恐龙动物群研究"项目(200313000051)
关键词
钙质结核
碳氧同位素
恐龙
侏罗纪
四川盆地
carbonate nodules carbon and oxygen isotope dinosaur
Jurassic
Sichuan basin
