Misplaced Pages

Xīnmínbǎo Group 新民堡群
Stratigraphic range: Late Barremian-Aptian
Type	Geological formation
Sub-units	Chijinbao Formation, Digou Formation, Xiagou Formation, Zhonggou Formation
Lithology
Primary	Conglomerate, siltstone, mudstone
Other	Sandstone
Location
Region	East Asia
Country	China  Mongolia

The Xīnmínbǎo Group (Chinese: 新民堡群; pinyin: Xīnmínbǎo qún) is a group of geological formations in north central China. They occur across a large depression between the Altai Mountains of Mongolia to the north and the Qilian mountains of the Qinghai Plateau to the south, in the Gōngpóquán (公婆泉) and Suànjǐngzi (算井子) basins, and also in the neighbouring Jiuquan Basin.

Both of these areas are inland basins consisting of fluvial (river), lacustrine (lake), and intermontane (between mountains) alluvial fan (floodplain) sediments that were deposited during the Early Cretaceous, probably during the Aptian or possibly late Barremian stage, when the climate was semi-arid and subtropical.

The group has been visited by many expeditions including the Silk Road dinosaur expedition of 1992 which concentrated on the area around Mazong Shan.

Geology

The group is made up of three main formations.

Chijinbao Formation

This consists of a lower red unit of coarse conglomerates grading to fine sandstones representing river channel to alluvial fan deposits, and an upper unit of red clastic sediments from either overbank deposits in a meandering fluvial environment, or accumulation in a shallow lacustrine or paludal (marsh) environment.

Digou Formation

This consists of grey siltstones and calcareous mudstones comprising two sequences of fluvio-lacustrine sedimentation with some alluvial fan and littoral (lake-shore) deposits.

Zhonggou Formation

This consists of red siltstones and mudstones in a series of upwardly coarsening cycles of lacustrine sediments.

Vertebrate fauna

The dinosaurs of the Xinminbao Group are collectively referred to as the Mazongshan Dinosaur Fauna, representing a unique dinosaur assemblage from all other known dinosaur faunas.

Ceratopsians

Ceratopsians reported from the Xinminbao Group
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Archaeoceratops	Archaeoceratops oshimai			" individuals lacking forelimbs."
Auroraceratops	Auroraceratops rugosus
Microceratus	Microceratus gobiensis
	Microceratus sulcidens
Psittacosaurus	Psittacosaurus mazongshanensis			"One individual lacking caudal and hindlimb."

Ornithopods

Saurischians

Saurischians reported from the Xinminbao Group
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Asiatosaurus	Asiatosaurus mongoliensis
Beishanlong	Beishanlong grandis				A deinocheirid ornithomimosaur.
Chiayusaurus	C. lacustris
Gobititan	Gobititan shenzhouensis
"Nanshiungosaurus"	"Nanshiungosaurus bohlini"			" cervical and dorsal vertebrae."	This species does not belong to Nanshiungosaurus.
Sinornithoides	Indeterminate

Thyreophorans

Indeterminate ankylosaur remains are known from the group.

Crocodilians

Indeterminate crocodilian remains are known from the group.

Fish

Pterosaurs

Pterosaurs reported from the Xinminbao Group
Genus	Species	Location	Stratigraphic position	Material	Notes	Images
Noripterus	Indeterminate

Turtles

See also

• List of dinosaur-bearing rock formations

References

1. You, H.; Morschhauser, E.M.; Li, D.; Dodson, P. (2019). "Introducing the Mazongshan Dinosaur Fauna". Journal of Vertebrate Paleontology. 38 (Memoir 18: Auroraceratops rugosus (Ornithischia, Ceratopsia) from the Early Cretaceous of northwestern Gansu Province, China): 1–11. doi:10.1080/02724634.2018.1396995.
2. ^ "Table 22.1," in Weishampel, et al. (2004). Page 479.
3. "Table 19.1," in Weishampel, et al. (2004). Page 415.
4. H.-l. You et al. (in press). "Gongpoquansaurus mazongshanensis (Lü, 1997) comb. nov. (Ornithischia: Hadrosauroidea) from the Early Cretaceous of Gansu Province, northwestern China". In David A. Eberth and David C. Evans (eds). Hadrosaurs: Proceedings of the International Hadrosaur Symposium. Indiana University Press. ISBN 978-0-253-01385-9. Check date values in: |date= (help)
5. "Table 19.1," in Weishampel, et al. (2004). Page 417.
6. "Table 18.1," in Weishampel, et al. (2004). Page 396.
7. Dong, Z.; You, H. (1997). "A new segnosaur from Mazhongshan Area, Gansu Province, China". In Dong, Z. M. (ed.). Sino-Japanese Silk Road Dinosaur Expedition. Beijing: China Ocean Press. pp. 90−95.
8. ^ Zanno, L. E. (2010). "A taxonomic and phylogenetic re-evaluation of Therizinosauria (Dinosauria: Maniraptora)". Journal of Systematic Palaeontology. 8 (4): 503−543. Bibcode:2010JSPal...8..503Z. doi:10.1080/14772019.2010.488045.
9. You, H.; Morschhauser, E. M.; Li, D.; Dodson, P. (2018). "Introducing the Mazongshan Dinosaur Fauna". Journal of Vertebrate Paleontology. 38 (sup. 1): 1−11. Bibcode:2018JVPal..38S...1Y. doi:10.1080/02724634.2017.1396995.

Further reading

• A new Psittacosaur (Psittacosaurus mazongshanensis sp. nov.) from Mazongshan area, Ganzu Province. Xu, X. Sino-Japanese Silk Road dinosaur expedition., Dong, Z. (ed). China Ocean press; 48-67 (1997).
• Biostratigraphy and palaeoenvironment of the dinosaur-bearing sediments in Lower Cretaceous of Mazongshan area, Gansu Province, China. Tang, F., Luo, Z., Zhou, Z., You, H., Georgi, J., Tang, Z., and Wang. X. Cretaceous Research 22, 115-129 (2001).

• Geologic groups of Asia
• Geologic formations of China
• Geologic formations of Mongolia
• Lower Cretaceous Series of Asia
• Barremian Stage
• Aptian Stage
• Conglomerate formations
• Mudstone formations
• Sandstone formations
• Siltstone formations
• Fluvial deposits
• Lacustrine deposits
• Fossiliferous stratigraphic units of Asia
• Paleontology in China
• Paleontology in Mongolia