Sihetun (NIGP coll): Late/Upper Barremian, China

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Insecta - Odonata - Megapodagrionidae
Cretapodagrion sibelleae n. gen., n. sp. Huang et al. 2017
1 specimen
NIGP 166620
Insecta - Hemiptera - Palaeontinidae
Ilerdocossus hui (Ren et al. 1998)
Li et al. 2018 1 specimen
NIGP 154994
Insecta - Hemiptera - Procercopidae
Stellularis sp. Chen et al. 2015
Chen et al. 2020 1 specimen
NND08013
see common names

Geography
Country:China State/province:Liaoning
Coordinates: 41.6° North, 120.8° East (view map)
Paleocoordinates:44.1° North, 122.9° East
Basis of coordinate:based on nearby landmark
Geographic resolution:outcrop
Time
Period:Cretaceous Epoch:Early/Lower Cretaceous
Stage:Barremian 10 m.y. bin:Cretaceous 2
Key time interval:Late/Upper Barremian
Age range of interval:125.77000 - 121.40000 m.y. ago
Stratigraphy
Geological group:Jehol Formation:Yixian
Stratigraphic resolution:group of beds
Stratigraphy comments: The Yixian Formation can be subdivided into five units, in ascending order, Lujiatun unit, Lower Lava, Jianshangou unit, Upper Lava, Dawangzhangzi unit, Jingangshan unit, and Huanghuashan unit. Most of the Jehol fossils from the Yixian Formation are preserved in four beds, that is, the Lujiatun bed (recalculated age is 124.0 ± 1.0/1.3 Ma, He et al., 2006), the Jianshangou bed (125.43 ± 0.50/0.88 Ma, Swisher et al., 1999), the Dawangzhangzi bed, and Jinggangshan bed (~122 Ma, Smith et al., 1995).U-Pb dating suggests that the Huangbanjigou section ranges from 124.9 ± 1.7 Ma to 122.8 ± 1.6 Ma (Yang et al., 2007). Chang et al. (2017) obtained Ar/Ar ages of 125.8 ± 1.0 Ma and 126.0 ± 0.8 Ma from the Lujiatun Unit, the lowest part of the Yixian Formation, below the lacustrine shales.
He et al. (2004) reported a 40Ar/39Ar age of 120.3 ± 0.7 Ma for a tuff layer in the lower part of the Jiufotang Formation, and Chang et al. (2009) obtained a 40Ar/39Ar age of 122.1 ± 0.3 Ma for a tuff layer from the lowermost part of the Jiufotang Formation. Yu et al. (2021) dated an ash bed just above the Yixian/Jiufotang formation boundary to 122.0 ± 0.9 Ma and three tuff beds from the Xiaotaizi section to 118.9 ± 0.8 Ma, 118.8 ± 0.6 Ma, and 118.6 ± 1.1 Ma. These ages suggest that the Jiufotang Formation in Jianchang Basin was deposited at ca. 122.0–118.9 Ma.
Olierrok et al. (2019) used a selection of U-Pb and 40Ar-39Ar geochronology to place the Barremian–Aptian boundary (the base of the Chron M0r) between 123.8 and 121.8 Ma. The GTS 2020 uses an age of 121.4 Ma for the base of the Aptian, and multiproxy orbital tuning gives an age of 120.2 Ma for the Barremian-Aptian boundary (Leandro et al., 2022). Therefore, the Yixian Formation should be entirely Late Barremian, with the Jiufotang Formation deposited in the Early Aptian (or latest Barremian at its base).
Lithology and environment
Primary lithology: lithified mudstone
Environment:lacustrine - large Tectonic setting:rift
Taphonomy
Modes of preservation:adpression
Size of fossils:macrofossils
Collection methods and comments
Reason for describing collection:taxonomic analysis
Museum repositories:NIGPAS
Metadata
Database number:190928
Authorizer:M. Clapham Enterer:M. Clapham
Modifier:M. Clapham Research group:paleoentomology
Created:2017-12-22 12:12:18 Last modified:2023-07-19 23:06:29
Access level:the public Released:2017-12-22 12:12:18
Creative Commons license:CC BY
Reference information

Primary reference:
64213. D. Y. Huang, D. Azar, and A. Nel. 2017. The oldest 'Megapodagrionidae' (Odonata, Zygoptera) discovered in the Lower Cretaceous Yixian Formation, China. Cretaceous Research 84:426-430 [M. Clapham/M. Clapham]

Secondary references:

71803 J. Chen, B. Wang, Y. Zheng, H. Jiang, T. Jiang, H. Bozdoğan, J. Q. Zhang, B. Z. An, X. L. Wang and H. C. Zhang. 2020. Taxonomic review and phylogenetic inference elucidate the evolutionary history of Mesozoic Procercopidae, with new data from the Cretaceous Jehol Biota of NE China (Hemiptera, Cicadomorpha). Journal of Zoological Systematics and Evolutionary Research 58:174-193 [M. Clapham/M. Clapham/M. Clapham]
67520 Y. L. Li, J. Chen, and B. Wang. 2018. New Cretaceous palaeontinids (Insecta, Hemiptera) from northeast China. Cretaceous Research 95:130-137 [M. Clapham/M. Clapham]