Tải bản đầy đủ - 0trang
Chapter 80. Biostratigraphy of Paleogene non-marine Ostracoda from East China
D.s. VANNIEUWENHUISE AND F. M.SWAIN
1154 J. D.HE,
ASSEMBLAGE I I
ASSEMBLAGE IVl B
ASSEMBLAGE lV2 0
in East China from which ostracode assemblages were obtained.
111. Echinocypris fabaeformis-Cyprinotus
(Heterocypris) jianglingensis assemblage of the
IV, Non-marine type : Cyprinotus (Heterocypris) macronefandus-Cyprinotus (Heterocypris)
igneus assemblage of the Late Eocene.
IV2. Marginal marine type: Cyprinotus (Heterocypris) yongningensis-Austrocypris levisChinocythere subcornuta assemblage of the Late Eocene.
V,. Non-marine type : Cyprinotus (Cyprinotus)hubeieniss-Cyprinotus (Heterocypris)jinheensisPinnocypris postiacuta assemblage of the Oligocene.
V,. Marginal marine type : Hebein ia-Huabeinia-Dongyinia- Candona-ParachinocytheveChinocythere assemblage of the Oligocene.
Assemblage I was first found in the Shanghu Formation of the Nanxiong Basin in 1964 (Guan,
1978). During the Paleocene, the most abundant and widespread Mesozoic forms, such as Cypridea and Talicypridea species, dwindled and vanished. They were replaced with similar Cenozoic
genera, Cypridea (Cypridea) xindianensis HOU,1978, C . (Guangdongia) speciosa Guan, 1978, c.
(Pseudocypridina) subtera Hou, 1978, Parailyocypris taizhouensis Yang, 1982, Ilyocypris sub-
Paleogene Non-marine Ostracodafrom East China 1155
EARLY TERTIARY OSTRACODES OF EAST CHINA
;?-Stratigraphic ranges of Early Tertiary ostracodes of East China.
huanggianoensis Hou and Yang, 1982, Porpocypris subglobra (Zhou), 1982, and Cyprois depressa
Chen, 1982 (Guan, 1978; He, 1979).
The greatest resemblance among the Paleocene ostracode species is found in those from the
Chejiang Formation in Hengyang Basin of Hunan, the Lower Member of Fangjiahe Formation in
the marginal region of the Yang tze-Han River Plain of Central Hubei and in the First Formation
of the Funning Group in Northern Jiangsu (Text-fig. 3). They are characterized by the presence
of rare Cypridea and by several Cenozoic genera. The assemblage can be correlated with similar
ostracodes in Fort Union Formation in the Western Interior of the United States (Swain et al.,
1971). Assemblages from both regions contain bisulcate Cypridea, such as Cypridea (Guangdongia)
speciosa Guan, 1978, which is closely similar to Cypridea nyensis Swain, 1964.
Assemblage I1 has a widespread distribution and a preponderance of typical Cenozoic genera
J. D.HE, D. S. VANNIEUWENHUISE
AND F. M. SWAIN
v ) d
b 8 'Nanxiong Sanshui Leiqiong Nanning Hengyang Dongting c
111 Danxia Frn
Shanghu Xinzhuang Changliu
Chejiang '$ First
Mbr u Mbr
Lower .g Lower
TJXT-FIG.3-Correlation of the Early Tertiary strata bearing non-marine ostracods in East China.
and species, The assemblage consists mainly of Cypris decaryi Gauthier, 1933, C.favosa Ye, 1978,
Eucypris stagnalis Mandelstam, 1963, Eucypris subtriangular Ye, 1978, Sinocypris funingensis Ho,
1982, S. Parailyocypris changzhouensis Yang and Hou, 1982, Limnocythere hubeiensis Ye, 1978,
and L. spinisulata Ye, 1978 (Hou et al., 1978, 1982).
Sinocypris is the most abundant ostracode throughout the entire Lower Eocene, but especially
in the lower part of the Lower Eocene. A non-marine ostracode assemblage very similar to this
assemblage is known from the Colton and Wasatch formations in the Western Interior of the
United States (Swain, 1964) and the White Bed of Nemegt Basin in Mongolia (Szczechura, 1971).
An important form, such as Sinocypris funingensis Ho, 1982, is very similar to Hemicyprinotus
watsonensis Swain in its weakly reticulate surface. Other species of the assemblage, such as Cypris
favosa Ye, 1978, are very similar to Pseudoeucypris pagei (Swain, 1956) of the Colton Formation
in the Western Interior of the United States. Hemicyprinotus watsonensis and Pseudoeucypris
pagei are zonally significant in the Colton Formation in Colorado, Utah, and Wyoming. In the
Western Interior of the United States, Cypridea-like species are rarely found in the Eocene and
Some of the Cenozoic non-marine ostracodes probably evolved from Cypridea (Text-fig. 4).
In morphology, especially the compressed mid-dorsal area and inner microstructure, Sinocypris
is related to Quadracypris. Among the other significant forms of Sinocypris is S. reticulata Zhang
and Guan, 1978. Sinocypris reticulata may have evolved from S.funingensis; it is subtriangular in
outline, highest anteromedially; the left valve is slightly larger than the right, overlapping along
free margins, especially the anterodorsal margin. These morphological features are quite similar
to other types of Late Paleogene and Neogene ostracodes. It is suggesteed that Sinocypris reticulata
is more advanced than Sinocypris funingensis and it has a greater geographic distribution. Follo-
Paleogene Non-marine Ostracoda from East China 1157
Baishuicun m =Basin ?
:'u Middle 4th
Yuhangding Dainan Fr
wing the evolutionary development of Sinocypris, the ostracode assemblage of the Early Eocene
can also be separated into two subassemblages. The lower Early Eocene subassemblage includes
Sinocypris funingensis Ho, 1982, S. multipuncta Ho, 1982, and is associated with many other Cenozoic species. This subassemblage occurs in the Second, Third and Fourth Formations of the
&Possible evolutionary relationships of several taxa.
1158 J. D. HE,
AND F. M.SWAIN
Funning Group of Jiangsu, the Buxin Formation of Sanshui Basin, the Luofuzhai Formation of
Nanxion Basin and the Lower Member of the Liushagang Formation of Leiqiong subregion, the
Xialiushi Formation of Hengyang Basin, the Second Formation of the Zhanghe Group of Zhejiang
and the Middle Member of the Shuangta Group of Xuanguang Basin. The subassemblage of
ostracodes from the upper part of the Early Eocene consists mainly of Sinocypris reticulata Zhang
and Guan, 1978. This species is widely distributed in the Dainan Formation of Jiangsu, the
Limuping Formation of Hengyang Basin, the Huayong Formation of Sanshui Basin, the Upper
Member of the Fangjiahe Formation of Hubei and the Upper Member of the Shuangta Group of
Worthy of notice is that the Early Eocene Continental Basin in East China can separated into
two biogeographic regions: the northern and the southern, with the area from Lianyunguang to
Quinling Moutains as the borderland. The two regions can easily be distinguished from each other
by the presence of Sinocypris in the southern region and its absence in the northern region.
Assemblage I11 is the Middle Eocene assemblage. Following the extinction of Sinocypris at the
end of the Early Eocene, Echinocypris and Cyprinotus became the dominant non-marine ostracodes,
possessing strongly endemic characteristics. This assemblage consists of Echinocypris elongata
Jiang and Li, 1978, E. fabaeformis Li, 1978, Cyprinotus (Heterocypris)jianglingensis He and Zhang,
1982, C. (H.) formalis Schneider, 1963, and a few specimens of Candona, Zlyocypris, Eucypris
and Limnocythere (He et al., 1982). Assemblage I11 has been found at several localities such as
in the Jingsha Formation of the Jianghan Plain, the Deshan Formation of Dongting Basin, the
Daicangfang Formation of Nanyang Basin and the Lower Member of the Sanduo Formation of
Jiangsu. However, Echinocypris is mostly limited to Hubei, Hunan and Henan Provinces. The
echinulate forms have not been seen in the First Member of Sanduo Formation. Both are characterized by the presence of numerous species and individuals of Cyprinotus, especially in the
Jiangsu Province. The faunas can be correlated with each other on the basis of Cyprinotus spp.
Middle Eocene Land Mammals were found in the Daicangfang Formation of Henan. These
include Coryphodon sp., Palaeosyops sp., cf. Breviodon sp. and Euryodon minimus Xu et al., 1979
(Li and Ting, 1983).
Besides the above-mentioned series of ostracode bearing rocks in East China, there are nonfossiliferous rock sequences which consist of reddish-brown sandstones and conglomerates, such as
the Danxia Formation of Nanxiong Basin, the Shiziling Formation of the Western Jianghan Plain,
and the First Member of the Kongdian Formation to the lower part of the Fourth Member of the
Shahejie Formation of the Coastal Region of Bohai. Present interpretations are that these strata
overlie the Cypris-Sinocypris-Eucypris-Parailyocypris-Limnocythere assemblage of Early Eocene.
The nonfossiliferous strata series seem to be Middle Eocene.
Assemblage IVI. (Non-marine type) In this assemblage, the Cyprinotus (Heterocypris) spp. are
very diverse in species with abundant populations, represented chiefly by Cyprinotus (Heterocypris)
macronefandus Li, 1978, and C. (H.) igneus Hou et al., 1978. The assemblage occurs in the Qianjiang Formation of the Jianghan Plain, in the Hetaoyuan Formation of Nanyang Basin, in the
middle part of the Fourth Member of the Shahejie Formation of the Coastal Region of Bohai
and in the Hedi Formation of Yuanqu Basin. However, the genera and species of assembage IV
are different in the East China Region. For example, the assemblage of the Jianghan Plain consists
of Cypris decaryi Gauthier, 1933, C . (H.) gonganensis He and Zhang, 1982, Pseudostenocypria?
triangularis He and Zhang, 1982, Paracandona euplectella (Brady and Norman, 1889), Zlyocypris
biplicata Sars, 1838, Z. cornae Mandelstam, 1961 and Virgatocypris ovata He and Zhang, 1982.
(He et al., 1982). In the Coastal Region of Bohai, ostracodes are less abundant. There, Cyprinotus
(Heterocypris) igneus Hou et al., 1978, is associated with a few species of Cypris, Eucypris and
Cyprois (Hou et al., 1978).
Paleogene Non-marine Ostracodafrom East China 1159
In addition, a rich Late Eocene land mammal assemblage co-occurring with ostracode assemblage IVl was recently discovered in the Hetaoyuan Formation of Henan and in the Hedi Formation of Yuangu Basin (Li and Ting, 1982). Characteristic fossils are Zctopidium lechei Zdansky,
1930, Hoanghonius stehlini Zdansky, 1930, Cricetodon schaubi Zdansky, 1930, Hyaenodon yuanchuenesi Young, 1937, Chailicyon crassidens Chow, 1975, Rhinotitan mongoliensis (Osborn, 1925),
?Amynodon mongoliensis (Osborn, 1930), Sianodon sinensis (Zdansky, 1930), Anthracokeryx sinensis
Assemblage IV, has only been found in a few localities which are the upper part of the Fourth
Member of the Shahejie Formation in Coastal Region of Bohai, the Upper Member of the
Liushagang Formation of Leiquiong subregion and the Yongning Formation of Nanning Basin.
This assemblage is allied to, but distinct from, both non-marine freshwater ostracode assemblages
and sub-littoral marine ones. In other places, only a few taxa and individuals occur. The Yongning
Formation is represented by Xiyingia cuneata He, 1981, Cyprinotus (Heterocypris) yongningensisHe,
1981, Zlyocpris jinjiensis He, 1981, Chinocythere xixiangtangensis He, 1981 and C. subcornuta He,
1981 (He, 1981). Ostracodes from the upper part of the Fourth Member of the Shahejie Formation
are represented by Cypris postilonga Hou et al., 1978, Candona acclivis Hou et al., 1978, Austrocypris levis Hou et al., 1978, A. posticaudata Hou et al., 1978, Pterygocypris caudata Hou et al.,
1978, Miniocypris subaequalis Hou et al., 1978, Limnocythere longipilerformis Hou et al., 1978,
L. nodosa Hou et al., 1978, L. striatituberosa Hou, et al., 1978, Chinocythere Iongicymbiformis
Hou et al., 1978, C. ventricostata, Hou et al., 1978. (Hou et al., 1978). This fauna is abundant and
diverse. Ostracodes are rare in the Upper member of the Liushagang Formation, which includes
mainly species of Eucypris and Chinocythere (South Sea Branch of Petroleum Corporation of the
People’s Republic of China et al., 1981).
The characteristics of assemblage IV, are summarized as follows :
1) Assemblage IV, is characterized by species of a few common freshwater genera such as
Cypris, Cyprinotus, Candona, Zlyocypris and Limnocythere as well as new forms, such as Austrocypris, Xiyingia, Pterygocypris, Miniocypris, and Chinocythere. The new forms bear some of the
same carapace features as nearshore marine and brackish forms, for example, Chinocythere
resembles Leptocythere, which is a marine genus. Chinocythere is quite similar to saline non-marine
forms of Elkocythereis found in the upper and middle parts of the Humboldt Formation of northeastern Nevada in the United States. Austrocypris bears some resemblance to Cytherura, the latter
being a shallow-marine form. In addition, in the Coastal Region of Bohai and in the same horizons
with the above-mentioned ostracodes, there have also been reported foraminifera-Dejlandrea
and Cladosiphonia-but, curiously enough, no typical marine ostracodes have been discovered
(Hou et al., 1978). The marginal marine or saline lake assemblage seems to be related more to
saline than to fresh-water masses, suggesting that there may have been a sea invasion at that time,
or that the lakes evaporated significantly and became saline enough to support foraminifera.
2) Austrocypris, Chinocythere and Xiyingia are brackish-water genera that seem to have originated in the Coastal Bohai Basin, Nanning Basin and Leiquiong subregion and are not found
elsewhere in China.
3) Assemblage IVI (Non-marine) and assemblage IV, (marginal marine) have several similar
genera and species. For example, Cyprinotus (Heterocypris) sp. 1 from the Hedi Formation of
the Yuangqu Basin (unpublished manuscript). Thus the ostracode assemblage of the transitional
type can be correlated with the ostracode assemblage of the continental type and on the basis of
land mammal ages (LMA) they are regarded as Late Eocene.
Assemblage V1 (Non-marine type) is represented chiefly by Cyprinotus (Cyprinotus) hubeiensis
He, 1982, C. (Heterocypris) jingheensis (Li, 1978), C. (H.) jintanensis He, 1982, Pinnocypris
postiacuta Zhou, 1982, P.alata Zhou and Cyprois xiangxiangensis Guan, 1978, which are associated
1160 J. D. HE,D. S. VANNIEUWENHUISE
AND F. M. SWAIN
with a few species of Cypris, Eucypris, Pseudoeucypris, Ilyocypris and Limnocythere. The species
of Cyprinotus are numerous and widely distributed. The assemblage is believed by Chinese scientists
to be Oligocene on the basis of charophytes and ostracodes. The abundant species of this
assemblage are very similar to those of the Renova Formation of the Jefferson Basin in the United
States. The same or closely similar species of Cyprinotus (Heterocypris), Cyprois and Ilyocypris
are also found in the Renova Formation. The principal difference between the two regions is that
the species of the subgenus Cyprinotus (Cyprinotus) and the genus Pinnocypris do not occur in
the Renova Formation of the Jefferson Basin.
Assemblage V, (Transitional type) This assemblage is very rich in both species and individuals.
New forms, such as Huabeinia, Tuozhuangia, Hebeinia, Dongyingia, Camarocypris, Ninghainia,
Glenocypris, Xiyingia, Berocypris, Crepocypris, Megacypris, Guangbeinia,Fusocandona, Phacocypris,
Ammocypris, Chinocythere, Potamocyprella, Pterygocypris, Minocypris, Nexypria, Stipitalocythere,
Parachinocythere, Nanningcythere are most abundant, as well as a few common freshwater
species of Cypris, Eucypris, Virgatocypris, Herptocyprella, Cyprinotus, Candona, Paracandona,
Tuberocyproides. Cycloscypris, Cypria, Cyprois, Zlyocypris, Ilyocyprimorpha, Metacypris and
Limnocythere. This assemblage was first found in the First, Second and Third members
of the Shahejei Formation and in the Dongying Formation in Coastal Region of Bohai (Hou
et al., 1978). Later it was recorded from the Weizhou Formation of Leiquiong subregion and
the Yongning Formation of Nanning Basin. (South Sea Branch of Petroleum Corporation
of the People’s Republic of China et al., 1981; He, 1981). The generic components of the Third
Member of the Shahejie Formation up to and including Dongin Formation are numerous, but
the Weizhou Formation and Yongning Formation, although similar on the whole, have only
a few genera.
From the character of the ostracode assemblages, assemblagesV, and IV, are alike, but assemblage V, embraces many new forms which reach their peak of diversity in the assemblage. The
marine organism Leglunia, Pentagonus, fossil tubes of Serpulimorpha and foraminifera have also
been discovered in the Coastal Region of Bohai (Hou et al., 1978). Additionally, some results
from Early Tertiary shales of the Yongning Formation in Guangxi (He, 1981), indicate that the
“equivalent boron” is around 200 ppm (see Walker and Price, 1963), suggesting an oligohaline
marginal marine or saline lake environment.
Appreciation is expressed to the Department of Geology, the University of Delaware, which
provided facilities for study. The work at the University of Delaware was partly supported by a
grant from the National Science Foundation (EAR-8304028) to F. M. Swain. Appreciation is
also expressed to the Amoco Production Company, Tulsa Research Center for supporting field
work in southwestern Montana and’ to W. B. Hanson and Dr. R. W. Pierce of Amoco for
reviewing the southwestern Montana Tertiary successions.
K.A. and SWAIN,
F.M. 1967. Late Cenozoic Freshwater Ostracoda and Cladocera from Northeastern
Nevada. J. Paleont.. 41, 335-350, 5 pls.
Paleogene Non-marine Ostracodafrom East China 1161
1978. On fossil ostracodes from the Nanxiong Basin and their stratigraphic significance. Paper of
Stratigraphy and Paleontology, 4, 151-1 59.
HE, J.D. 1931. Early Tertiary Ostracodes from the Naming Basin in Guangxi. Bull. Nanjing Inst. Geol. and Palaeont., Acad. Sinica, no. 3, 211-240, 7 pls.
-and JUAN, R.J. 1979. Late Cretaceous-Paleogene deposits of the Nanxiong Basin, Guangdong. Acta Stratigr.
Sinica, 3, (l),
-and ZHANG. X.J.
-~ Cretacious-Tertiarv Ostracodes from the Yanatze-Han River Basin in Hubei. Bull.
Nanjing Inst. Geol. and Palaeont.. Acad. Sinica, no. 5, 177-213, 7 pls.
HO, J.D. 1979. Late Cretaceous-early Eocene Ostracods from Nanxiong Basin Guangdong Province. In Mesozoic
and Cenozoic Red Beds of South China, 240-268, 6 pls. Science Press, Beijing.
HOU, Y.T. et al. 1978. Early Tertjary Ostracode fauna from the Coastal Region of Bohai. 205 pp., 83 PIS. Science
-et al. 1978. The Cretaceous-Tertiary Ostracodes from the marginal region of the Yangtze-Han River Plain in
Central Hubei. Mem. Nanjing Instit. Geol. and Paleont. Acad. Sinica, 9, 130-206, 19 PIS.
-et al. 1979. Advance in study of Mesozoic and Cenozoic Ostracoda in China. In KRSTIC, N. (ed.). Taxonomy, Biostratigraphy and Distribution of Ostracodes, 103-108, Serbian Geological Society, Beograd.
-et al. 1982. Cretaceous-Quaternaryostracodefauna from Jiangsu. 254 pp., 88 PIS. Geological Publishing House,
-et al. 1982. Subdivision and correlation of the Cenozoic strata in China. In Stratigraphic correlation chart in
China with explanatory text. 286-299., 19 tabs. Science Press, Beijing.
KIHM, A.J. and MIDDLETON, M.D. 1980. Tertiary vertebrate biostratigraphy of Colorado. Rocky Mountain Assoc. Geologists-1980 Symposium, 157-1 63.
KUENZE, W.D. and FIELDS, R.W. 1971. Tertiary Stratigraphy, Structure, and Geological History, Jefferson Basin,
Montana. Geol. SOC.Am., Bull., 92, 3373-3394.
LI, C.K. and TING, S.Y. 1983. The Paleogene Mammals of China. Bull. Carnegie Mus. Nut. Hist. no. 21, 1-97.
MOORE, R.C. 1958. Introduction to Historical Geology, 432-455, McGraw-Hill Book C., Inc., New York.
POMERAL, c . 1982. The Cenozoic Era, Tertiary and Quaternary. Ellis Horwood Ltd., Chichester.
ROBINSON, G.D. 1963. Geology of the Three Forks Quadrangle Montana. US. Geol. Survey. Prof. Paper, 3 7 0 , 6 8 0 .
SOUTH SEA BRANCH OFPETROLEUM CORPORATION OFTHE PEOPLE’S REPUBLIC OF CHINA, el a[. 1981. Tertiary PUkOntOlOgJ’
ojNorth Continental Sherfof South China Sea. Guangdong Science and Technology Press.
SWAIN, F.M. 1949. Early Tertiary Ostracoda from the Western Interior United States. J . Paleon?., 23,172-181, 2 PIS.
- 1956. Early Tertiary ostracode zone of Vinta Basin. Intermountain Assoc. Petroleum Geologists, Field Con$
Guidebook, 125-138,3 PIS.
, BECKER, J. and DICKINSON, K.A. 1971. Paleoecology of Tertiary and fossil Quaternary nomarine Ostracoda
from the Western Interior United States. In OERTLI, H.J. (ed.). PalCo&ologie des Ostracodes. Bull. Centre Rech.
Pau-SNPA, 5 supple., 461-487.
SZCZECHURA, J. 1971. Freshwater Ostracoda from the Paleocene of the Nemegt Basin, Gobi Desert, Mongolia.
Paleont. Polonica, no. 25, 85-96, 4 PIS.
WALKER, C.T. and PRICE, N.B. 1963. Departure curves from computing paleosalinity from boron in illites and shale.
Bull. Am. Assoc. Petrol. Geol., 47 (51, 833-841.
YANG, S.Z. 1983. Paleoecology of Late Eocene and Oligocene Ostracoda from Bohai Bay Basin. In MADDOCKS
R.F. (ed.). Applications of Ostracoda. 286312, Department of Geoscience, Univ. Houston, Texas.
ZHENG, J.J. and QIN, Z.T. 1979. A discussion of Cretaceous and Lower Tertiary continental strata of South
China. In the Mesozoic and Cenozoic Red Beak of South China, 1-57. Science Press, Beijing.
This Page Intentionally Left Blank
Cretaceous and Palaeogene Ostracod Biostratigraphy
in Xining and Minhe Basins of China
Y I - c m HAO
Beqing Graduate School of Wuhan College, P. R. China
The Xining and Minhe Basins bordering on each other around Ledu in northwestern China
cover a wide area from the west of Lanzhou in Gansu province to the east of Xining in Qinghai
province (Text-fig. 1). In these inland basins, Mesozoic-Cenozoic terrestrial deposits of great
thickness and rich in mineral resources such as coal, oil and salt, have been deposited. The
Cretaceous and Palaeogene strata, which range from about 1,400 to 3,400 meters in thickness,
contain abundant remains comprising microfossils such as non-marine ostracods, charophytes,
spores and pollen, as well as macrofossils including freshwater bivalves, gastropods, estherians,
freshwater fishes, reptiles and plants.
In the present paper, biostratigraphy of the Cretaceous and the Palaeogene is discussed in terms
of ostracod and charophyte assemblages.
CRETACEOUS AND PALAEOGENE
The Cretaceous is divided in ascending order into the Datonghe Formation which includes part
of the Upper Jurassic, the Hekou Formation and the Minhe Formation (Ha0 et al., 1982, 1983).
The Datonghe Formaion is mainly represented by greyish-green and greyish-white, sandy conglomerate and sandstone with interbedded brown mudstones in its lower part; by brown and brownish-red mudstone and siltstone with intercalations of greyish-green and brown sandstone and
variegated shale in its middle part, and by brick-red sandstone and conglomerate with intercalations of thin-bedded brown silty mudstone in its upper part.
The Hekou Formation comprises reddish-brown sandstone and sandy conglomerate in its
lower part; reddish-brown and green mudstone with variegated shale containing interbedded sandstone in its middle part, and reddish-brown mudstone, reddish-brown, orange conglomeratic
sandstone and sandy conglomerate with intercalated reddish-brown mudstone in its upper part.
The Minhe Formation is lithologically subdivided into two parts. The lower part consists of
reddish-brown sandy conglomerate and the upper part of reddish-brown mudstone and siltstone
with interbedded greyish-green sandstone and gypsum.
The Palaeogene strata comprise in ascending order the Qijiachuan Formation, the Honggou
Formation and the Mahalagou Formation (Ha0 et al., 1983).
The Qijiachuan Formation consists of clastic deposits mainly represented by dark brown
mudstone, silty mudstone and greyish-brown greyish-green sandstone with gypsolite intercalations
and brown coloured basal conglomerate.
STRATIGRAPHY AND FOSSIL
ASSEMBLAGE SEQUENCES IN XINING
AND M~N HE
- . .-.
-. O .
0 . 0 .
0 . 0 .
. 0 . 0 . 0 .
.-. .-. .
- - -_
0 . 0 . 0 . 0
. O .
- - ..- .0 . 0 . 0 . 0
Moedlerisphaera chinensis Huang and XuGrovesichara minheensis Yang Assemblage
Limnocythere hubeiensis Ye-L.
languida Song Assemblage
Gyrogona qianjiangica Z. Wang-Sphaerpchara minheensis Yang Assemblage
Talicypridea reticulata (Hou)-Cypridea
(Cypridea) cavernosa Galeeva-Cypridea
(Pseudocypridina) longa Hou-Eucypris
qinghaiensis Song Assemblage
Cypridea (Cypridea) sanmachiensis SongRhinocypris ventriconcava Hao-Ziziphocypris costata (Galeeva) Assemblage
Cypridea (Cypridea) unicostata GaleevaCypridea (Ulwellia) koskulensis Mandelstam Assemblage
Lycopterocypris infantilis-L. flaccida Song
Minheella minheensis Song and ChengJingguella hutouyaiensis Hao-Damonella
huangshuiensis Hao-Protolimnocythere pingua Cheng Assemblage
llyocypris ellipsoidea-Eucypris milagouensis
jucundus Song Assemblage
Cypris decaryi Gautheir-Limnocythere
hubeiensis Ye Assemblage
. 0 . 0 . 0 .
Stephanochara breviovlis Lin and HuangNeochara squalida Z. Wang and Lin Assemhlage
Latochara curtula Z. Wang-Gyrogona hubeiensis Z. Wang-Charites guanpingensis
Flabellocharajurongica S. Wang and Zhang
caii S. Wang-Mesochara
Minhechara columelaria Wei-Multispirochara subovalis Assemblage
Aclistochara datongheensis Wei-A.
bransoni Peck Assemblage
Gypsum Gypsum mudstone