Yanan Formation

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Yanan Formation
Stratigraphic range: Toarcian–Bajocian
TypeGeological formation
Sub-unitsY1, Y2, Y3, Y4, Y5
UnderliesZhiluo Formation
Overlies
Thicknessup to 220 metres (720 ft)
Lithology
PrimarySandstone, siltstone, mudstone, shale
OtherCoal
Location
Coordinates38°06′N 106°42′E / 38.1°N 106.7°E / 38.1; 106.7Coordinates: 38°06′N 106°42′E / 38.1°N 106.7°E / 38.1; 106.7
Approximate paleocoordinates42°06′N 111°42′E / 42.1°N 111.7°E / 42.1; 111.7
RegionNingxia, Shaanxi, Inner Mongolia
Country China
ExtentOrdos Basin
Type section
Named forYan'an
Yanan Formation is located in China
Yanan Formation
Yanan Formation (China)

The Yanan Formation, alternatively spelled the Yan'an Formation (simplified 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[4] and the remains of the sauropod Lingwulong[5] having been found in the formation.

References[]

  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. 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. 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. 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. 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.
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