Precambrian Research, 29 (1985)5--14 5 Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands

A L G A L M A C R O F O S S I L S F R O M T H E Q I N G B A I K O U S Y S T E M IN T H E Y A N S H A N R A N G E O F N O R T H C H I N A

DU RULIN and TIAN LIFU

Department of Geology, Hebei College of Geology, Xuanhua, Hebei (People's Republic of China)

(Received May 16, 1984; revision accepted August 26, 1984)

ABSTRACT

Du, R.L. and Tian, L.F., 1985. Algal macrofossils from the Qingbaikou System in the Yanshan Range of North China. Precambrian Res., 29: 5--14.

In the Yanshan Range algal macrofossils of the Qingbaikou System are widespread, numerous, varied and well preserved. They occur at the same stratigraphic level over a large area. They occur mainly in the second member of the Changlongshan Format ion (900--850 Ma old). They are the fossils of marine planktonic and sessile multicellular Metaphyta with possible relationships to the Phaetophyta and Chlorophyta.

There are two families, nine genera and 21 species. The type specimens were col- lected from Mt. Longfengshan in Huailai County and Mt. Lishugou in Xinglong County, Hebei Province. Longfengshania exhibits clear differentiation of organs (a foliate and a parastem). In addition a rhizome (organ of " f ixa t ion") was observed at the base of some of the parastems.

Such fossils are rare both in China and elsewhere. They provide remarkable evidence for the evolution of higher algae in the late Precambrian and are possibly the earliest benthonic algal macrofossils in the world. The assemblage of macrofossils is called the Huailai Algal Flora. These occurrences have considerable significance, both in the evolu- tion of organisms and for stratigraphic subdivision and correlation.

INTRODUCTION

In r e c e n t y e a r s a lga l m a c r o f o s s i l s such as C h u a r i a have b e e n r e c o g n i s e d in m a n y r e g i o n s o f N o r t h C h i n a (X ing , 1 9 7 9 ; Du , 1 9 8 2 ; D u a n , 1 9 8 2 ) . T h e m a t e r i a l s d e s c r i b e d in t h i s p a p e r w e r e c o l l e c t e d f r o m t h e Q i n g b a i k o u S y s t e m o f t h e Y a n s h a n R a n g e in H e b e i P r o v i n c e , Be i j ing a n d T i a n j i n M u n i c i p a l i t y . T h e Q i n g b a i k o u S y s t e m is c o n s i d e r e d t o be b e t w e e n a b o u t 1 0 0 0 a n d 8 0 0 M a o l d . T h e s e d i m e n t a r y r o c k s a re u n m e t a m o r p h o s e d a n d t h e m a x i m u m t h i c k n e s s o f t h e S y s t e m is a b o u t 7 6 0 m. T h e l o w e r p a r t , t h e X i a m a l i n g F o r m a t i o n , is c o m p o s e d o f sha les ; t h e m i d d l e p a r t , t h e C h a n g l o n g s h a n F o r - m a t i o n c o n s i s t s m a i n l y o f s a n d s t o n e s i n t e r c a l a t e d w i t h sha l e s a n d t h e u p p e r p a r t , t h e J i n g e r y u F o r m a t i o n , is m a d e u p o f b e d d e d l i m e s t o n e s .

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G E O G R A P H I C A L D I S T R I B U T I O N A N D S T R A T I G R A P H I C POSITION

In the Yanshan Range, the Qmgbaikou System is well developed and quite fossiliferous. Algal macrofossils were found at 11 places and 17 localities such as Huailai, Zhoulu, Xinglong, Fengrun, Kuancheng Counties, Guye town, Hebei Province and Qingbaikou village, Changping, Beijing (Fig.

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7

TABLE I

The distribution of the genera and species of the maeroalgal fossils in the Qingbaikou System of the Yanshan Range

~ the regions and ,. West memb. East memb. I " ~ formations Xi~,aling F ' m . Changlongshan Fro,

('huaria sp.

( ' . circularis

('. annuluris

f ' . multirugos'a

Shouhsienia sp,

Sh. shouhsienensis

S~. Ionga

Sh. multirugosu

Ooidiscina sp.

O. hagong shani ca

O. Iongu

Pumilihaxa sp. Pumilihaxa el. huaiheianu

GIossophk, ton sp.

G. huailuiensis

G. Jbli formi.s

G. huuilaiensis

l 'awuia sp. T. dalensis

Longf(,ngshania sp,

L. stipituta

L. ooali s

L. gemmi Jbrma

L. elongata

L. spheria

L, longi pet i olata

Phascolites sp.

Ph. symmetricus

Paralongfengshania sp.

Paralong f engshania sic yoides

1). They are widespread, well preserved, varied and have a distinct strati- graphic position.

There are two main fossiliferous horizons in the Qingbaikou System: (1) the lower horizon is within the Xiamaling Formation (Fig. 2) with monoto-

nous, small primitive forms wi thout a marginal ring; and (2) the upper hori- zon is in the Changlongshan Format ion (Fig. 2). It has three subhorizons.

Based on lithologic character, the upper horizon can be subdivided into two areas, namely West Yanshan and East Yanshan. In West Yanshan black-

Plate I: Fig. 1. Chuaria circularis Walcott, 1899; X 4, LcNo 112. Locali ty and horizon, Changlongshan Format ion of Qingbaikou System in Longfengshan Mt. Huailai, Hebei Province. Fig. 2. Chuaria circularis Walcott, 1899; X 15, JCL-25. Locali ty and horizon. Changlongshan Format ion of Qingbaikou System in Jixian. Tianjing. Fig. 3. Chuaria circularis Walcott, 1899; X. 15, Fd082. Locali ty and horizon, Nanfen Format ion of Xihe Group in Fuxian, Liaoning Province. Fig. 4. Chuaria circularis Walcott, 1899; X 8.5, GC008. Locali ty and horizon, Changlongshan Format ion o f Qingbaikou System in Fengrun. Hebei Province. Fig. 5. Chuaria circularis Walcott, 1899; X 30, Fd016. Locali ty and horizon, Nanfen Format ion of Xihe Group in Fuxian, Liaoning Province. Fig. 6. Chuaria sp; X 10, Jt 13. Locali ty and horizon, Tuanshanzi Format ion of Changcheng System in Jixian, Tianjing. Fig. 7. Chuaria annularis Zheng, 1981; X 15, Noo l . Locality and horizon, Changlongshan Format ion of Qingbaikou System in Kuancheng, Hebei Province. Fig. 8. Chuaria annularis Zheng, 1981; X 6, GC012. Locali ty and horizon, Changlongshan Format ion of Qingbaikou System in Fenren, Hebei Province. Fig. 9. Chuaria annularis Zheng, 1981; X 4, Lc No 23. Locali ty and horizon, Changlongshan Format ion of Longfengshan Mt. Huailai. Hebei Province. Figs. 10, 11. Chuaria multi- rugosa D u e t Tian*; X 3, LcNo 455; X 3, LcNo 132. Locali ty and horizon, Changlong- shan Format ion of Longfengshan Mt. Huailai, Hebei Province. Fig. 12. Shouhsienia shouhsienensis Xing, 1979; X 10, ZX007. Locality and horizon, Xiamaling Format ion of Qingbaikou System. Zhaojiashan Mt. Huailai, Hebei Province. Fig. 13. Shouhzienia shouhsienensis Xing, 1979; X 2.5, Lc No 72. Locali ty and horizon, Changlongshan For- mation of Qingbaikou System. Longfengshan Mt. Huailai, Hebei Province. Fig. 14. Shouhsienia longa Xing, 1979; X 2, LcNo 019a. Locali ty and horizon, Changlongshan Format ion of Qingbaikou System. Xinglong, Hebei Province. Fig. 15. Shouhsienia longa Xing, 1979; X 2, LcNo 462. Local i ty and horizon, Changlongshan Format ion of Qing- baikou System. Longfengshan Mt. Huailai, Hebei Province. Figs. 16, 17. Shouhsienia multirugosa Du et Tian; X 2, LcNo 126; X 25, LcNo 381. Locali ty and horizon, Chang- longshan Format ion of Qingbaikou System, Longfengshan Mt. Huailai, Hebei Province. Fig. 18. OvMiscina bagongshanica Zheng, 1981; X2, LcNo 329. Locali ty and horizon, Changlongshan Format ion o f Qingbaikou System, Longfengshan Mt. Huailai, Hebei Province. Fig. 19. Ovidiscina bagounshanica Zheng, 1981; X 30, Zx003. Locali ty and horizon, Xiamaling Format ion of Qingbaikou System, Zhaojiashan Mr. Houailai, Hebei Province. Fig. 20. Ovidiscina longa D u e t Tian**; X 2.5, LcNo 332. Locali ty and hori- zon, Changlongshan Format ion of Qingbaikou System, Longfengshan Mt. Huailai, Hebei Province. Fig. 21. Pumilibaxa cf huaiheiana Zheng, 1981; X 2, LcNo 734. Locali ty and horizon, Changlongshan Format ion of Qingbaikou System, Longfengshan Mr. Huailai, Hebei Province. Fig. 22. Glossophyton huailaiensis Duan et Du*; X 2, LcNo 188. Locali ty and horizon, Changlongshan Format ion of Qingbaikou System, Longfengshan Mr. Huai- lai, Hebei Province. Fig. 23. Glossophyton foliformis Duan et Du*; X 3, LcNo 315. Locality and horizon, Changlongshan Format ion of Qingbaikou System, Longfengshan Mt. Huailai, Hebei Province. Fig. 24. Glossophyton mucronatus Duan et Du*, X 2.8, LcNo 412. Locali ty and horizon, Changlongshan Format ion of Qingbaikou System, Longfengshan Mt. Huailai, Hebei Province. Fig. 25. Phascolites symmetricus Duan et Du*; X 3, LcNo 177a. Local i ty and horizon, Changlongshan Format ion of Qingbaikou System, Longfengshan Mt. Huailai, Hebei Province. Fig. 26. Tawuia dalensis Hofmann, 1979; X 2, LcNo 204. Local i ty and horizon, Changlongshan Format ion of Qingbaikou System, Longfengshan Mr. Huailai, Hebei Province. Fig. 27. Tyrasotaenia sp? X 7, Jch 03. Locali ty and horizon, Chuanglinggou Format ion of Changcheng System. Jixian, Tianjing. Fig. 28. Trace fossil; X 2, Jg-1. Locali ty and horizon, Gaoyuzhuang Format ion of Changcheng System, Jixian, Tianjing.

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ish-grey shales contain fossils that are large (diameter 5--9 mm, usually > 4 mm) of varied type and have a relatively complex structure with a marginal ring. The Longfenshan Mountain of Huailai County can be con- sidered as the type locality. Two families, nine genera and 21 species have been identified to date (Table I). The fossils of East Yanshan occur in greyish-green shales, except for those of Xinglong County. They are general- ly small (1--3 mm), monotonous in type and simple in structure, but have a marginal ring. Six genera and nine species have been recognised in East Yanshan.

Some of these fossils are also found in other regions of North China such as Liaoning, Jilin and Anhui Provinces.

EVOLUTION AND ECOLOGY

The marginal rings of the macroalgal fossils from both western and eastern Yanshan, regardless of their size, all occur in the Changlingshan stage. This feature is assumed to reflect an evolutionary trend, independent of the habitat or depositional environment.

Mineralogical analysis of fossiliferous rocks reveals that they are chiefly composed of iUitic shale with organic matter, together with subsidiary amounts of kaolinite, sericite, pyrite and quartz. Horizontal laminations are well preserved. The algal macrofossils are well preserved and are associated with some other probable sessile organisms and trace fossils. The habitat of such fossils is inferred to have been a restricted, relatively quiet, weakly reducing, warm, tidal flat.

The evolutionary course of Precambrian macroalgae can be divided into three stages. (1) Pre-Qingbaikou period {1700 -- 1000 Ma), the fossils found in the Chuanlinggou and other Formation possibly represent the oldest macroalgae (Hofmann and Chen, 1981; see Plate I, Figs. 6, 27 and 28 of this paper). Fossils of the Pre-Qingbaikou period are small, simple banded, thread- like or discoidal carbonaceous remains. (2) Early Qingbaikou or Xiamaling period {1000--900 Ma). These macroalgal fossils are characterized by transitional features. (3) Late Qingbaikou or Changlongshan period (900 - 850 Ma). In this period macroalgae are more complex and are represented by the Huailai Flora. The fossils of each of these stages have their own unique characteristics so that they can be used for stratigraphic subdivision and correlation.

HUAILAI FLORA

In the Longfengshan Mountains of northwest Huailai County, algal macro- fossils of the Changlongshan Formation constitute a biota with distinctive regional features. This biota is named the Huallai Flora after the place where the first discoveries were made. Longfengshania is its typical representative.

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The body of Longfengshania consists of a foliate and a parastem which looks like a stalk; a rhizome has been observed at the base of some parastems (Plate II).

The parastem is important in taxonomic studies. The appearance of this feature is accompanied by other changes in form, size, structure, ornament and the ecological characteristics of the fossil. It is therefore justified to set up a new family called Longfengshaniaceae. The function of the parastem may be similar to that o f the stem in higher plants. The parastem not only supports the foliate, connecting it with the rhizome, but also held the foliate up to sunlight for photosynthesis in the water. Some species of Longfengshania are probably the earliest benthonic algal macrofossils in the world.

Perhaps there is a genetic relationship between Longfengshania and Chuaria as suggested below:

Chuaria.

Glossophyton huailaiensis Shouhsi (with a melon seed-like tip)

Longfengshania gemmiforma ~ Longfengshania stipitata

(with a bud-parastem) (with a moderate parastem)

Longfengshania longipetiolata (with a long parastem and a developed fixation "organ")

The fossils do not appear to have undergone any distortion. All of them have a similar symmetrical elongate form. Many exhibit surface ornamenta- tion such as marginal rings of variable width, ring veins and inner-ring-veins. Some of them appear to exhibit "organic differentiat ion" similar to that of higher plants. Chemical analysis of the fossils revealed the presence of some hydrocarbon compounds. By the study of peels, Laminarites antiqu- issimus Eichw., Margominuscula cf. tenela Naum., Trachysphaeridium simplex Sin were identified. L. antiquissimus is thought to be a fragment of an ancient phaeophyta (brown alga), a multiceUular organism with nu- cleated cells and showing "organic differentiat ion" and evidence of having led a sessile benthonic life. These attributes are similar to those of the algal macrofossils of the Chanlongshan Format ion which probably filled a similar ecological niche and are probably related to either Phaeophyta or Chloro- phyta.

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ACKNOWLEDGEMENTS

The writers thank Prof. Yang Zunyi and Prof. Bai Shuenliang for their inspiration and guidance in the writing of this paper. We are especially grateful to Xu Xuemin who has always supported us in different but equally important ways and thanks go out to Wang Qizheng and Li Hanbang for their help.

REFERENCES

Du Rulin, 1982. The discovery of the fossil such as Chuaria in the Qingbaikou System in Northwestern Hebei and their significance. Geo. Rev., 28: 1- 7 (in Chinese).

Du Rulin and Tian Lifu, 1985. The study on Chuaria and the other Macro-algal Fossils of Qingbalkou System in Yanshan Range. Hebei People's Press (in Chinese, in press).

Duan Chenghua. 1982. Late Precambrian algal megafossils Chuaria and Tawuia in some area of eastern China. Alcheringa, 6: 57--68.

Duan Chenghua and Du Rulin, 1985. Megascopic Palaeo-algae. In: Xing Yusheng (Editor), The Palaeontology and its Stratigraphical Significance in Upper Precambrian of China. (in Chinese and in press).

Hofmann, H.J. and Aitken, J.D., 1979. Precambrian biota from the Little Dal Group, Mackenzie Mountain, Northwestern Canada. Can. J. Earth Sci., 16: 150--156.

Hofmann, H.J. and Chen Jinbiao, 1981. Carbonaceous megafossils from the Precambrian (1800 Ma) near Jixian Northern China. Can. J. Earth Sci., 18: 443--447.

Walcott, C.D., 1899. Precambrian fossiliferous formation. Bull. Geol. Soc. Am., 10: 199--244.

Plate II: Figs. 1--5. Longfengshania stipitata Du, 1982; X 2, LcNo 193; X 2, LcNo 602; X 2, Lc No 019; X 2, LcNo 282a; X 2, LcNo 625. Locality and horizon, Changlongshan Formation of Qingbaikou System, Longfengshan Mt. Huailai, Hebei Province. Figs. 6--9. Longfengshania ovah's Du et Duan*;X 2, LcNo 243b; X 2, LcNo 719a; X 2.5, LcNo 200, X3, LcNo 417b. Locality and horizon, similar to those in Figs. 1--5. Fig. 10. Longfeng- shania gemmiforma D u e t Tian**; X 1.5, LcNo 242a. Locality and horizon, similar to those in Figs. 1--5. (Fig. 10 shows the preferred orientation of the fossils.) Figs. 11- 12. Longfengshania elongata D u e t Duan*; X 2, LcNo 146; X 2, LcNo 241. Locality and horizon, similar to those in Figs. 1--5. Fig. 13. Paralongfengshania sicyaides Du et Duan; X 2, LcNo 397. Locality and horizon, similar to those in Figs. 1--5. Fig. 14. Longfeng- shania longipetiolata D u e t Tian**; X 1.2, LcNo 785. Locality and horizon, similar to those in Figs. 1--5. Fig. 15. Longfengshania spheria Du et Tian**; X 2.5, LcNo 250. Locality and horizon, similar to those in Figs. 1--5. Figs. 16-- 18. Longfengshania longi- petiolata D u e t Tian; X 2, XcNo 215, X 2, XcNo 501; X 1.5, LcNo 782. Locality and horizon, Figs. 17, 18, similar to those of Figs. 1--5; Fig. 16, Changlongshou Formation of Qingbaikou System, Xinglong, Hebei Province. Fig. 19. Longfengshania ovalis Chuaria, Shouhsienia occur in a superposition way. X 1, XcNo 188. Locality and horizon, Chang- longshan Formation of Qingbaikou System, Xinglong, Hebei Province.

All specimens are preserved in Hebei College of Geology, Xuanhua, Hebei, People's Re- public of China. Fossil descriptions are given in the two references cited below.

* Duan Chenghua and Du Rulin, 1984. ** Du Rulin and Tian Lifu, 1985.

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Xing Yusheng, 1979. The Sinian system of China. Scientific papers on Geology for Inter- national Exchange. Stratigraphy and Paleontology, 2:10--12 (in Chinese).

Zheng Wenwu, 1981. A new occurrence of fossil group of Chuaria from the Sinian System in North Anhui and its Geological meaning. Bull. Chin. Acad. Geol. Sci., Ser. VI, 1:50--67 (in Chinese).