in Jurassic and Cretaceous Stratigraphy

Earth Science Frontiers, Vol. 17, Special Issue, Aug. 2010 ISSN 1005-2321
Late Early Jurassic Floras in the North of China and Their
Palaeoclimate Implications
Shenghui Deng 1 , Yuanzheng Lu 1 , Guobin Fu 2 , Ru Fan 1 , Wenzhe Duan 1
1. State Key Laboratory of Enhanced Oil Recovery(Research Institute of Petroleum Exploration and Development,
PetroChina)Beijing 100083, China (E-mail: shdeng2001@yahoo.com.cn)
2. Research Institute of Petroleum Exploration and Development of Turpan-Hami Oil Company, PetroChina Hami 839009, Xinjiang,
China
The terrestrial upper Lower Jurassic strata are
extremely developed in China, of which those in the
South of China are chiefly composed of red beds,
usually without plant fossils; while the other in the
North of China are consist of coal-bearing or no-coal
sediments containing abundant plant fossils (Deng et al.,
2003). These strata include the Sangonghe Formation
of the Junggar and Turpan-Hami Basins of Xinjiang
(Deng et al., 2000; 2010), the Tianshuigou and Yinma-
guo Formations of the Qiadam Basin(Li et al., 1988),
Qinghai Province, the Fuxian Formation of the Ordos
Basin of Shaanxi Province (Huang et al., 1980), the
Jiashan Formation of Northern Hebei Province (Wang,
1984), Alatanheli and Nansuletu Formations of Inner
Mongolia (Wang, 1984), and the Beipiao Formation of
Liaoning Province(Mi et al., 1996), which all yield
abundant plant fossils.
Based on the fossils from the above formations,
the main characteristics of late Early Jurassic floras in
the North of China are summarized. The floras are of
less abundance and lower diversity compared with the
earlier or later ones in every locality, generally con-
sisting of one or two dozen species, and only in a few
localities over 50 species. The floras are usually
dominated by ferns and Ginkgopsida, with many
Cycadopsida, some sphenopsids and conifers. It is
noticeable that the floras are obviously different from
the ones of both the underlying and overlying strata in
having more thermophilous or arid-tolerant elements,
which include ferns belonging to the Dipteridaceae,
Matoniaceae, Marattiaceae, Schizaeaceae and Glei-
cheniaceae; Otozamites, Zamites and Ptilophyllum of
the Bennettitalean, Hirmeriella, Brachyphyllum and
Pagiophyllum of the Cheirolepidiaceae(conifer) and
also some Gnetalean plants, such as Ephedrites and
Cadmisega ephedroides.
The high content of these thermophilous and arid-
tolerant plants indicate that the climate in the North of
China during the late Early Jurassic is hotter and more
arid than that of the earlier and latter periods, which is
possibly linked with the Toarcian palaeoenvironment
event (Vakhrameev, 1991).
Additionally, palynological analysis has also indi-
cated sharp content peaks (usually 50%-70%) of the
cheirolepidiaceous pollen Classopollis, which is con-
sidered as a good hot and arid climate indicator
(Vakhrameev, 1991), appear in the plant fossil-bearing
beds. This supports the palaeoclimate changing during
the late of the Early Jurassic in the North of China.
Key words: Upper of the Lower Jurassic; Flora;
Toarcian; Palaeoclimate; North of China
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