Yanan Formation

Yanan Formation
Yanan Formation
Stratigraphic range: Toarcian–Bajocian PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Sub-units	Y1, Y2, Y3, Y4, Y5
Underlies	Zhiluo Formation
Overlies	Fuxian Formation
Thickness	up to 220 metres (720 ft)
Lithology
Primary	Sandstone, siltstone, mudstone, shale
Other	Coal
Location
Coordinates	38°06′N 106°42′E / 38.1°N 106.7°E
Approximate paleocoordinates	42°06′N 111°42′E / 42.1°N 111.7°E
Region	Ningxia, Shaanxi, Inner Mongolia
Country	China
Extent	Ordos Basin
Type section
Named for	Yan'an
	Yanan Formation (China) Yanan Formation (Ningxia)

The Yanan Formation, alternatively spelled the Yan'an Formation (Chinese: 延安组), is a geological formation in China, it is also alternatively considered a group. The age of the formation is uncertain, with estimates ranging from Toarcian to Bajocian. It is divided up into 5 members, with the designation of Y1 through Y5. Y2, Y3 and Y4 are predominantly dark shales, while Y1 and Y5 are composed of sandstones, coal beds^[1] and interbedded mudstones. The depositional environment at the time was when the Ordos Basin formed a large inland lake, surrounded by floodplains. The dark shales have been explored for the potential of producing shale gas.^[2] The coal has also been explored for the production of coalbed methane.^[3] The formation is also notable for its fossil content, with dinosaur footprints having been found in the formation.^[4] The dinosaur Lingwulong was formerly thought to have been found in this formation,^[5] but the strata was later attributed to the overlying Zhiluo Formation.^[6]

Fossil content

Color key

Taxon	Reclassified taxon	Taxon falsely reported as present	Dubious taxon or junior synonym	Ichnotaxon	Ootaxon	Morphotaxon

Notes
Uncertain or tentative taxa are in small text; ~~crossed out~~ taxa are discredited.

Dinosaurs

Sauropods

Sauropods of the Yanan Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Lingwulong^[7]	L. shenqi				A dicraeosaurid sauropod. The attribution to the Yanan Formation was later found to be erroneous, and the species actually comes from the overlying Zhiluo Formation.^[6]

Insects

Insects of the Yanan Formation
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Parasinitsia^[8]	P. qingyunensis				A campterophlebiid damsel-dragonfly
Sinagonophlebia^[9]	S. yananensis				A paragonophlebiid damsel-dragonfly
Yananthemis^[9]	Y. zaoyuanensis				A selenothemistid damse-dragonfly

References

^ Ao, Weihua; Huang, Wenhui; Weng, Chengmin; Xiao, Xiuling; Liu, Dameng; Tang, Xiuyi; Chen, Ping; Zhao, Zhigen; Wan, Huan (January 2012). "Coal petrology and genesis of Jurassic coal in the Ordos Basin, China". Geoscience Frontiers. 3 (1): 85–95. Bibcode:2012GeoFr...3...85A. doi:10.1016/j.gsf.2011.09.004. ISSN 1674-9871.
^ Wang, Dong-dong; Shao, Long-yi; LI, Zhi-xue; LI, Ming-pei; Lv, Dawei; Liu, Haiyan (September 2016). "Hydrocarbon generation characteristics, reserving performance and preservation conditions of continental coal measure shale gas: A case study of Mid-Jurassic shale gas in the Yan'an Formation, Ordos Basin". Journal of Petroleum Science and Engineering. 145: 609–628. Bibcode:2016JPSE..145..609W. doi:10.1016/j.petrol.2016.06.031. ISSN 0920-4105.
^ Xu, H.; Tang, D.Z.; Liu, D.M.; Tang, S.H.; Yang, F.; Chen, X.Z.; He, W.; Deng, C.M. (June 2012). "Study on coalbed methane accumulation characteristics and favorable areas in the Binchang area, southwestern Ordos Basin, China". International Journal of Coal Geology. 95: 1–11. Bibcode:2012IJCG...95....1X. doi:10.1016/j.coal.2012.02.001. ISSN 0166-5162.
^ Xing, Lida; Lockley, Martin G.; Tang, Yonggang; Klein, Hendrik; Zhang, Jianping; Persons, W. Scott; Dai, Hui; Ye, Yong (2015-01-02). "Theropod and Ornithischian Footprints from the Middle Jurassic Yanan Formation of Zizhou County, Shaanxi, China". Ichnos. 22 (1): 1–11. Bibcode:2015Ichno..22....1X. doi:10.1080/10420940.2014.985670. ISSN 1042-0940. S2CID 129509962.
^ Xu, Xing; Upchurch, Paul; Mannion, Philip D.; Barrett, Paul M.; Regalado-Fernandez, Omar R.; Mo, Jinyou; Ma, Jinfu; Liu, Hongan (2018-07-24). "A new Middle Jurassic diplodocoid suggests an earlier dispersal and diversification of sauropod dinosaurs". Nature Communications. 9 (1): 2700. Bibcode:2018NatCo...9.2700X. doi:10.1038/s41467-018-05128-1. ISSN 2041-1723. PMC 6057878. PMID 30042444.
^ ^a ^b Dai, Hui; Tan, Chao; Xiong, Can; Ma, Qingyu; Li, Ning; Yu, Haidong; Wei, Zhaoying; Wang, Ping; Yi, Jian; Wei, Guangbiao; You, Hailu; Ren, Xinxin (2022). "New macronarian from the Middle Jurassic of Chongqing, China: phylogenetic and biogeographic implications for neosauropod dinosaur evolution". Royal Society Open Science. 9 (11): 220794. Bibcode:2022RSOS....920794D. doi:10.1098/rsos.220794. PMC 9627447. PMID 36340515. However, valid Middle Jurassic neosauropods are rarely reported before the discovery of dicraeosaurid Lingwulong from middle/late Middle Jurassic (late Bathonian–early Callovian) (The horizon was revised from Yan'an Formation (Aalenian–Bajocian) to Zhiluo Formation (Bathonian–early Oxfordian)
^ Xing Xu; Paul Upchurch; Philip D. Mannion; Paul M. Barrett; Omar R. Regalado-Fernandez; Jinyou Mo; Jinfu Ma; Hongan Liu (2018). "A new Middle Jurassic diplodocoid suggests an earlier dispersal and diversification of sauropod dinosaurs". Nature Communications. 9 (1): Article number 2700. Bibcode:2018NatCo...9.2700X. doi:10.1038/s41467-018-05128-1. PMC 6057878. PMID 30042444.
^ Tian, F.; Zheng, D.; Nel, A.; Ye, Y.; Mei, T.; Zhang, H. (2023). "A new campterophlebiid damsel-dragonfly (Odonata: Isophlebioidea) from the Middle Jurassic Yanan Formation of Yulin City, Shaanxi Province, NW China". Comptes Rendus Palevol. 22 (23): 491–496. doi:10.5852/cr-palevol2023v22a23. S2CID 259852598.
^ ^a ^b Nel, A.; Xu, M.; Wang, Y.; Song, X.; Gao, J.; Ji, G.; Huang, D. (2024). "New Chinese Jurassic damsel-dragonflies of the families Paragonophlebiidae, Selenothemistidae and Isophlebiidae (Odonata, Epiproctophora) from the Jurassic Ordos Basin of NW China". Geobios. doi:10.1016/j.geobios.2024.08.014.

[1] Ao, Weihua; Huang, Wenhui; Weng, Chengmin; Xiao, Xiuling; Liu, Dameng; Tang, Xiuyi; Chen, Ping; Zhao, Zhigen; Wan, Huan (January 2012). "Coal petrology and genesis of Jurassic coal in the Ordos Basin, China". Geoscience Frontiers. 3 (1): 85–95. Bibcode:2012GeoFr...3...85A. doi:10.1016/j.gsf.2011.09.004. ISSN 1674-9871.

[2] Wang, Dong-dong; Shao, Long-yi; LI, Zhi-xue; LI, Ming-pei; Lv, Dawei; Liu, Haiyan (September 2016). "Hydrocarbon generation characteristics, reserving performance and preservation conditions of continental coal measure shale gas: A case study of Mid-Jurassic shale gas in the Yan'an Formation, Ordos Basin". Journal of Petroleum Science and Engineering. 145: 609–628. Bibcode:2016JPSE..145..609W. doi:10.1016/j.petrol.2016.06.031. ISSN 0920-4105.

[3] Xu, H.; Tang, D.Z.; Liu, D.M.; Tang, S.H.; Yang, F.; Chen, X.Z.; He, W.; Deng, C.M. (June 2012). "Study on coalbed methane accumulation characteristics and favorable areas in the Binchang area, southwestern Ordos Basin, China". International Journal of Coal Geology. 95: 1–11. Bibcode:2012IJCG...95....1X. doi:10.1016/j.coal.2012.02.001. ISSN 0166-5162.

[4] Xing, Lida; Lockley, Martin G.; Tang, Yonggang; Klein, Hendrik; Zhang, Jianping; Persons, W. Scott; Dai, Hui; Ye, Yong (2015-01-02). "Theropod and Ornithischian Footprints from the Middle Jurassic Yanan Formation of Zizhou County, Shaanxi, China". Ichnos. 22 (1): 1–11. Bibcode:2015Ichno..22....1X. doi:10.1080/10420940.2014.985670. ISSN 1042-0940. S2CID 129509962.

[5] Xu, Xing; Upchurch, Paul; Mannion, Philip D.; Barrett, Paul M.; Regalado-Fernandez, Omar R.; Mo, Jinyou; Ma, Jinfu; Liu, Hongan (2018-07-24). "A new Middle Jurassic diplodocoid suggests an earlier dispersal and diversification of sauropod dinosaurs". Nature Communications. 9 (1): 2700. Bibcode:2018NatCo...9.2700X. doi:10.1038/s41467-018-05128-1. ISSN 2041-1723. PMC 6057878. PMID 30042444.

[:0-6] Dai, Hui; Tan, Chao; Xiong, Can; Ma, Qingyu; Li, Ning; Yu, Haidong; Wei, Zhaoying; Wang, Ping; Yi, Jian; Wei, Guangbiao; You, Hailu; Ren, Xinxin (2022). "New macronarian from the Middle Jurassic of Chongqing, China: phylogenetic and biogeographic implications for neosauropod dinosaur evolution". Royal Society Open Science. 9 (11): 220794. Bibcode:2022RSOS....920794D. doi:10.1098/rsos.220794. PMC 9627447. PMID 36340515. However, valid Middle Jurassic neosauropods are rarely reported before the discovery of dicraeosaurid Lingwulong from middle/late Middle Jurassic (late Bathonian–early Callovian) (The horizon was revised from Yan'an Formation (Aalenian–Bajocian) to Zhiluo Formation (Bathonian–early Oxfordian)

[7] Xing Xu; Paul Upchurch; Philip D. Mannion; Paul M. Barrett; Omar R. Regalado-Fernandez; Jinyou Mo; Jinfu Ma; Hongan Liu (2018). "A new Middle Jurassic diplodocoid suggests an earlier dispersal and diversification of sauropod dinosaurs". Nature Communications. 9 (1): Article number 2700. Bibcode:2018NatCo...9.2700X. doi:10.1038/s41467-018-05128-1. PMC 6057878. PMID 30042444.

[8] Tian, F.; Zheng, D.; Nel, A.; Ye, Y.; Mei, T.; Zhang, H. (2023). "A new campterophlebiid damsel-dragonfly (Odonata: Isophlebioidea) from the Middle Jurassic Yanan Formation of Yulin City, Shaanxi Province, NW China". Comptes Rendus Palevol. 22 (23): 491–496. doi:10.5852/cr-palevol2023v22a23. S2CID 259852598.

[Sinagonophlebia-9] Nel, A.; Xu, M.; Wang, Y.; Song, X.; Gao, J.; Ji, G.; Huang, D. (2024). "New Chinese Jurassic damsel-dragonflies of the families Paragonophlebiidae, Selenothemistidae and Isophlebiidae (Odonata, Epiproctophora) from the Jurassic Ordos Basin of NW China". Geobios. doi:10.1016/j.geobios.2024.08.014.

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