We report new 40Ar/39Ar dating results ob-tained from total fusion and incremental-heating analyses of sanidine and biotite from three tuffs found interbedded within the fossil-bearing deposits of Liaoning, northeast ...We report new 40Ar/39Ar dating results ob-tained from total fusion and incremental-heating analyses of sanidine and biotite from three tuffs found interbedded within the fossil-bearing deposits of Liaoning, northeast China. The first is a new sample of the Bed 6 Sihetun tuff from the Yixian Formation, previously dated by our team as middle Early Cretaceous, and recently considered by Lo et al., partially reset due to metamorphism from a nearby ba-saltic sill. The second is the Yixian Bed 9 tuff from Heng-daozi considered by Lo et al. to be unaffected by metamor-phism and whose age, based on total fusion 40Ar/39Ar dating of biotite, argues for a Jurassic age for the Yixian Formation. The third tuff is a previously undated tuff from the upper part of the underlying Tuchengzi Formation. Single crystal total fusion 40Ar/39Ar analyses of the Sihetun sanidine showed homogeneous radiogenic Ar, Ca/K ratios, excellent reproducibility and gave a mean age of 125.0 ± 0.18 (1SD) ± 0.04 (SE) Ma. Single sanidine展开更多
辽宁北票义县组中的翼龙个体中等大小,尾短,具腹肋,前肢粗壮,桡、尺骨长于翼掌骨,后肢跖骨极细长,第Ⅴ趾退化但未消失等特征,表明它应为翼手龙亚目早期类型中一个新的属种——杨氏东方翼龙(Eosipterus yangi gen.et sp.nov.)。这是辽西...辽宁北票义县组中的翼龙个体中等大小,尾短,具腹肋,前肢粗壮,桡、尺骨长于翼掌骨,后肢跖骨极细长,第Ⅴ趾退化但未消失等特征,表明它应为翼手龙亚目早期类型中一个新的属种——杨氏东方翼龙(Eosipterus yangi gen.et sp.nov.)。这是辽西翼龙类化石的首次发现,为进一步确定热河动物群的性质、地质时代,以及研究古地理古环境等提供了新资料。展开更多
基金This work was supported bythe Special Fund for the Major State Basic Research Projects of China (Grant No. G000077700) the Chinese Academy of Sciences (Grant No. KZCX3-J-03)+1 种基金 the National Natural Science Foundation of China (Grant No. 49832002) th
文摘We report new 40Ar/39Ar dating results ob-tained from total fusion and incremental-heating analyses of sanidine and biotite from three tuffs found interbedded within the fossil-bearing deposits of Liaoning, northeast China. The first is a new sample of the Bed 6 Sihetun tuff from the Yixian Formation, previously dated by our team as middle Early Cretaceous, and recently considered by Lo et al., partially reset due to metamorphism from a nearby ba-saltic sill. The second is the Yixian Bed 9 tuff from Heng-daozi considered by Lo et al. to be unaffected by metamor-phism and whose age, based on total fusion 40Ar/39Ar dating of biotite, argues for a Jurassic age for the Yixian Formation. The third tuff is a previously undated tuff from the upper part of the underlying Tuchengzi Formation. Single crystal total fusion 40Ar/39Ar analyses of the Sihetun sanidine showed homogeneous radiogenic Ar, Ca/K ratios, excellent reproducibility and gave a mean age of 125.0 ± 0.18 (1SD) ± 0.04 (SE) Ma. Single sanidine
文摘辽宁北票义县组中的翼龙个体中等大小,尾短,具腹肋,前肢粗壮,桡、尺骨长于翼掌骨,后肢跖骨极细长,第Ⅴ趾退化但未消失等特征,表明它应为翼手龙亚目早期类型中一个新的属种——杨氏东方翼龙(Eosipterus yangi gen.et sp.nov.)。这是辽西翼龙类化石的首次发现,为进一步确定热河动物群的性质、地质时代,以及研究古地理古环境等提供了新资料。
