in Jurassic and Cretaceous Stratigraphy

Earth Science Frontiers, Vol. 17, Special Issue, Aug. 2010 ISSN 1005-2321
Progress on the Study of the Terrestrial Jurassic in Western Liaoning,
NE China
136
Baoyu Jiang 1 , Xiaogang Yao 2 , Yazhuo Niu 1 , Xin Yao 2 , Qijian Li 2
1. State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing
210093, China (E-mail: byjiang@nju.edu.cn)
2. Nanjing Institute of Geology and Palaeontology, Academia Sinica, 210008 Nanjing, China
The Lower and Middle Jurassic in western Liao-
ning consist of two volcanic- or volcaniclastic-
dominated rocks and a coal bearing deposits in between,
containing all kinds of fossils, such as plants, sporo-
pollen, bivalves, conchostracans. The lower volcanic-
or volcaniclastic-dominated rocks, the Xinglonggou
Formation, are sporadically outcropped in western
Liaoning. The coal-bearing Beipiao Formation contains
mainly megaplants and sporo-pollen. The megaplants
of the Biepiao Fomation belong to the Early – Middle
Jurassic Coniopteris – Phoenicopsis flora of northern
China (Si and Zhou, 1962). The sporopollen of Beipiao
Formation belongs to late Early Jurassic Cyathidites –
Cycadopites – Paleoconiferus assemblage of north
China (Song and Shang, 2000). The upper volcanic- or
volcaniclastic-dorminated rocks are much more widely
exposed in western Liaoning, including the Haifanggou
and Lanqi formations. The Haifanggou and Lanqi
formations contain the Unio—Ferganoconcha bivalve
assemblage, which belongs to the Early -Middle
Jurassic Lamprotula (Eolamprotula) cremeri –Kija
(=Pseudocardinia) kweichouensis fauna of northern
China (Gu, 1982). The megaplants belong to the early
Middle Jurassic (Haifanggou Formation) and the late
Middle Jurassic (Lanqi Formation) assemblages of the
Coniopteris – Phoenicopsis flora. Sporo-pollen of the
Haifanggou and Lanqi formations belong to the Middle
Jurassic Cyathidites – Cycadopites – Classopollis as-
semblage of north China (Song and Shang, 2000).
The recently discovered volcanic Daohugou Bed,
which located at the joint area of Liaoning, Hebei and
Inner Mongolia, contains insects, conchostracans,
plants, vertebrates, and other invertebrate fossils. The
Daohugou Bed was once erroneously considered as
belonging to the Yixian formation by Wang et al.,
(2000) and Wang (2000) based on their comparison of
the vertebrate fossils in both horizons. However, more
and more paleontological and radiometric evidences
show that the bed should be included into the
Haifanggou Formation which is correlated with the
Jiulongshan Formation in the northern Hebei province.
Vertebrate fossils include the amphibians Jeholotriton
paradoxus(Wang Yuan, 2000),Chunerpeton tianyien-
sis (Gao and Shubin, 2003) , Liaoxitriton daohu-
gouensis (Wang, 2004), pterosaurs Jeholopterus
ningchengensis (Wang et al., 2002), Pterorhychus
wellnhofers (Czerkas and Ji, 2002.), dinosaurs Epiden-
drosaurus ningchengensis (Zhang et al., 2002.), Pedo-
penna daohugouensis (Xu and Zhang, 2005), and early
mammals (mammaliaform) Castorocauda lutra-
similis(Ji et al., 2006).The Daohugou Bed produces
conchostracans Euestheria ziliujingensis, E. haifang-
gouensis, E. jingyuanensis and E. luanpingensis. These
fossils belong to the early Middle Jurassic Euestheria
ziliujingensis fauna of China (Shen et al., 2003). The
Daohugou Bed produces bivalve Ferganoconcha
sibirica, which belongs to the Early- Middle Jurassic F.
sibirica – Unio Shuangmiaoensis assemblage and the
Middle Jurassic Kija-Ferganoconcha assemblage of
Yanshan-Liaoning Region (Yu and Yao, 1989; Jiang,
2006). The Daohugou Bed produces a large amount of
insects. Ren et al. (2002), Rasnitsyn and Zhang (2004)
and Huang et al. (2006) compared the present insect
fauna with that of central Asia and Europe, especially
the Karatau of Kazakhstan, and concluded a Middle
Jurassic age of the insect fauna.
The Upper Jurassic Tuchengzi Formation consists
of mainly red sediments, containing rare concho-
stracans and sporo-pollen. Conchostracans include
Nestoria reticulate (Chernyshev), N. orbita (chen), and
Mesolimnadia jinlingsiensis Chen, which belong to the
Pseudograpta fauna of China. Pseudograpta are
commonly co-occurred with Nestoria and both of them
are characterized by huge reticulate ornamentation,
reflecting a Late Jurassic age (Zhang et al., 1976).
Sporo-pollen of the Tuchengzi Formation is called th
Classopollis assemblage, which also indicates a Late
Jurassic age (Song and Shang, 2000).
Recently achieved, high-precised radiometric
datings give strong support for subdivision of the
terrestrial Jurassic in not only western Liaoning, but
also the whole eastern Asia. Yang and Li (2008)
reported radiometric ages of the Xinglonggou
Formation from the Xinglonggou village of Beipiao
city, the Haifanggou Formation from the Daohugou
village (Daohugou Bed) of Ningcheng county, and the
Lanqi Formation from the Haifanggou village of
Beipiao city respectively. The results showed that age
of Xinglonggou Formation is 176.7±3.5 Ma, belonging
to late Early Jurassic (Toarcian); the ages of Hai-
fanggou Formation and Lanqi Formation are ranging
from 165 Ma to156 Ma, belonging to the Bathonian of
the Middle Jurassic to the Oxfordian of the Late
Jurassic, but mainly the Callovian of the Middle