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Chemostratigraphic correlation of the middle and upper proterozoic between the Yanshan and Shennongjia Basins
Precambrian Research, 29 (1985) 77--91 Elsevier Science Publishers B.V., Amsterdam -- Printed in The Netherlands
77
CHEMOSTRATIGRAPHIC CORRELATION OF THE MIDDLE AND UPPER PROTEROZOIC BETWEEN THE YANSHAN AND SHENNONGJIA BASINS
QIN ZHENGYONG', YANG XIUEN 2 and JIANG MINGMEI' ' Tianjin Institute o f Geology and Mineral Resources, Chinese Academy o f Geological Sciences, Tianjin 300170 (People's Republic o f China) 2Geological Bureau o f Hubei Province, Wuhan. Hubei (People's Republic o f China) (Received May 16, 1984; revision accepted September 1, 1984)
ABSTRACT
Qin, Z., Yang, X. and Jiang, M., 1985. Chemostratigraphic correlation of the middle and upper Proterozoic between the Yanshan and Shennongjia Basins. Precambrian Res., 29: 77--91. This paper is concerned with the distribution of major elements, transition elements, REE, sulphur isotopes and organic carbon in parts of the Proterozoic of China. Lithophile and ore-forming elements such as Ba, Sr, Mn, K, V, Fe and Cu are good chemical markers and are used for correlation in the Yanshan Basin. The Ba content is particularly high in red beds of several sections. Ba, Fe, K, Mn, V, Ca, Mg and organic carbon have provided useful data for correlation between the Yanshan and Shennongjia Basins. These elements reflect, in varying degree, widespread important geological events. We propose several chemostratigraphic stages with divisions approximately at 1950 Ma, 1600 Ma, 1200 Ma and 1000 Ma. These divisions correspond approximately to major time boundaries in the Proterozoic of China. 83"S values for sulphur isotopes in Proterozoic strata in China are between - 1 3 o/oo and + 27 o/oo. REE patterns, normalized to chondritic abundances, for middle--upper Proterozoic rocks of China, are similar to post Archaean sedimentary rocks of Australia. They also show Eu depletion and Eu/Eu* ratios between 0.6 and 0.8.
INTRODUCTION In C h i n a c h e m o s t r a t i g r a p h i c t e c h n i q u e s have b e e n u s e d in s t u d i e s o f m i d d l e a n d u p p e r P r o t e r o z o i c s t r a t a o f t h e J i x i a n s e c t i o n since 1974. In 1979 we used these m e t h o d s for subdivision of stratigraphic successions. The major elements, transition elements, rare earth elements, stable isotopes etc. in s e d i m e n t a r y r o c k s p r o v i d e m u c h u s e f u l i n f o r m a t i o n r e l e v a n t t o t h e g e o c h e m i c a l e n v i r o n m e n t a n d r e c y c l i n g a n d d i s t r i b u t i o n o f e l e m e n t s in t i m e a n d s p a c e . T h e g o a l s o f s u c h s t u d i e s are s u b d i v i s i o n a n d c o r r e l a t i o n a n d t o a p p r o a c h an u n d e r s t a n d i n g o f t h e e v o l u t i o n o f t h e a t m o s p h e r e , h y d r o s p h e r e a n d l i t h o s p h e r e . In t h i s p a p e r t h e c h e m i c a l a p p r o a c h is u s e d t o a t t e m p t correlation of middle and upper Proterozoic sediments within and between s e d i m e n t a r y b a s i n s in S o u t h a n d N o r t h C h i n a . 0301-9268/85/$03.30
© 1985 Elsevier Science Publishers B.V.
78 CHEMOSTRATIGRAPHIC CORRELATION BASIN O F N O R T H C H I N A
IN
THE
YANSHAN
SEDIMENTARY
Rock samples from five sections of the Yanshan Basin, including the Pangjiapu, Qinlingshan and Yanmenzi, in Hebei Province, Changping Ming Tombs and Jixian County in Tianjin (Fig. 1) have been systematically collected and analysed by the following methods: complete mineral and rock analyses, atomic absorption spectrometry, polarography and laser microprobe analyses. The data were then mathematically analysed using a computer. • ~etioo location ~ , ~ ~rata o f k~ddl¢ and Upper Proterozol¢
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Fig. 1. A s k e t c h m a p s h o w i n g a p p r o x i m a t e l o c a t i o n s o f s e c t i o n s o f t h e m i d d l e and u p p e r P r o t e r o z o i c in t h e Y a n s h a n region, China. l = X u a n h u a Pangjiapu; 2=Changping
Ming Tombs; 3=TianjinJixian; 4=Luanxian Qinglongshan; 5=KuanchengYamenzi. The middle and upper Proterozoic of the Jixian stratotype section was subdivided into five geochemical cycles, four systems and 14 formations by Qin Zhengyong et al. (1980). Based on chemostratigraphic data a new scheme of subdivision is suggested in this paper (Table I). An important chemical stage (c. 1600 Ma ago) is shown by a break at the base of the Gaoyuzhuang Formation. This break corresponds approximately to a global orogeny about 1500--1600 Ma ago. Chen Jinbiao et al. (1982) considered this to be the boundary between the middle and upper Proterozoic. The other boundary (c. 1000 Ma) is placed between the Qingbaikou and Yuyang chemical stages, so that the base of the Qingbalkou System is still placed at the ancient weathering surface of the Xiamaling Formation. The 1000 Ma event is probably of global significance. Three obvious lines of subdivision, based on major element chemistry, are shown in Fig. 2. The first is at the contact between the Dahongyu and Gaoyuzhuang Formations. Its values vary from 2 to 3. The second one, representing the boundary between the Wumishan and Hongshuizhuang Formations, ranges from 3 to 7 and the third boundary, between the Changzhougou and Chuanlinggou Formations has values ranging from 4 to 6. The
Fujunshan Fm.
Changzhougou Fm.
Chuanlin$$o u Fm.
Tuanshanzi Fm.
D a h o n g y u Fro.
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Y a n g z h u a n g Fro.
W u m i s h a n Fro.
H u n g s h u i z h u a n g Fro.
Tieling Fro.
X i a m a l i n g Fro.
Jingeryu Fm.
~
8
relation of Jixian Section
Contact
0
0
Contact relation o f regional s e c t i o n
1900
1700
1600
1400
1200
1000
900
Age (Ma)
Chemical stage of Changcheng
Chemical stage o f Jixian
Chemical stage of Yuyang
Chemical stage o f Qingbaikou
Chemical stage
T h e first subcycle
The second subcycle
"l~e first subcycle
The s e c o n d subcycle
The first cycle
The first subcycle
The s e c o n d sub cycle
T h e s e c o n d cycle
The third cycle
The f o u r t h cycle
T h e fifth cycle
G e o c h e m i c a l cycle
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*Lithological characteristics o f e v e r y cycle
U n d e r l y i n g strata: Qianxi G r o u p o f A r c h a e a n A - - C o n g l o m e r a t e r o c k ; B - - q u a r t z i t e ; C - - s a n d s t o n e ; I > - g l a u c o n i t i c s a n d s t o n e : E - s i l t y shale, I,'- shale: G - - l i m e s t o n e ; H - - d o l o m i t i c l i m e s t o n e , I-Lime d o l o m i t e ; J - d o l o m i t e ; K - - a r g i l l o a r e n a c e o u s c a r b o n a t i t e . *The d a t a were p u b l i s h e d b y Qin Z h c n y o n g ( 1 9 8 0 ) in a p r e l i m i n a r y s t u d y on the g e o c h e m i s t r y of the S i m a n S u b e r a t h e m in the Y a s h a n R a n g c , N o r t h China.
Changcheng System
Jixian System
Qingbalkou System
Lower Cambrian
L i t h o s t r a t i g r a p h i c units
B o u n d a r i e s and geochemical environments
C h e m o s t r a t i g r a p h i c s u b d i v i s i o n for the m i d d l e and u p p e r P r o t e r o z o i c in J i x i a n S e c t i o n
TABLE I
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MgO
o o.s ) 1,s 2 o i . . 2. . . 3 ~ ~ 0J, 0., 0 0.1 0.~ 0!~ 01, 6 0t2 0',-0'.e 0~ i' Fig. 2, Optimal Section boundaries and curves of oxide contents in sections of Yanshan sedimentary basin. A=Changping Ming Tombs; B=Jixian County; C=Yamenzi, Hebei Province; D=Qinlongshan, Hebei Province; a=Changzhougou Gin.; b=Chuanlinggou Fm.; c= Tuanshanzi Fm.; d=Dahongyu Fro.; e=Gaoyuzhuang Fro.; f=Yangzhuang Fm.; g=Wumishan Fro.; h=Hongshuizhuang Fro.; i=Tieling Fm.; j=Xiamaling Fro.; k=Jingeryu Fro.; Key. I=Jixian section; II=Ming Tombs section; III=Yamenzi section; IV=Qinlongshan section; V=Optimal Section grade.
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,.,
. . . . . . .I
,- ....
;
-,~-.
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io-~-'--~
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,--~-.-
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-
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81 major element compositions are obviously different above and below these boundaries. The Gaoyuzhuang, Yangzhuang and Wumishan Formations are mainly composed of dolomite, probably formed under weakly alkaline conditions (pH 8--9) at about 10 ° of palaeolatitude. The Hongshuizhuang and Jingeryu Formations consist of mudstone, limestone and siliceous dolostone. These rocks probably formed in neutral--weakly alkaline environments (pH 7--8). The Changzhougou Formation is mainly terrigenous fluvial deposits with very different geochemical characteristics from those of the mudstones and carbonates of the other units. The mean values for 13 elements and Clarke concentration values (ratios of these values to the corresponding Clarke values) show t h a t there is a systematic distribution of elements such as Ba, Sr, Mn, V, Fe and Cu. For example, the Ba ratio in the Jixian System, which is mainly carbonates, is >1. In particular Ba reaches its greatest concentrations with ratios of 13--40 in the Yangzhuang Formarion at several sections. These values were probably palaeochmatically controlled. In the Yangzhuang Formation of the Yanshan Basin Ba-rich red beds could have formed in a hot (and possibly humid) climate. Such red beds are c o m m o n l y used for correlation in this region. Most Sr values are lower than the Clarke values. Dolomitization may have been largely responsible for Sr depletion for when Mg replaced Ca during this process Sr was probably also lost. Based on Mn distribution we think that the Gaoyuzhuang Formation was deposited in the reducing, somewhat restricted environment of a rehct sea. There are two occurrences of Mn ore in the Gaoyuzhuang Formation of Jixian County. One is chambersite in deeper locations and the other is pyrolusite and psilomelane in association with pyrite and galena in the oxiTABLE II Important elements in sections of the Yanshan region Lithostratigraphic units
Elements
Qingbaikou System
Jingeryu Fm. XiamalingFm.
Ni.Cr.CoMln.Ba.Ti.V.Zr. V.Mn.
Jixian
Tieling Fm. Hungshuizhuang Fm. Wumishan Fm. Yangzhuang F r o . Gaoyuzhuang Fro.
Mn.Ba.Zr. Zr.V. Cu .Ba. Cu.Ba.Ti.Zr. Cu.BaMIn.Zr.Cr.
System
Changcheng System
Dahongyu Fm. Tuanshanzi Fm. *Chuanlinggou Fro. Changzhougou Fro.
V.Co.Ba.Ti.Zr.B.Co.Mn.Cu. V.Cr.Ba.Ti.B.Ni.Co.Cu.Zr. Mn.V.Ni.Co.Cu.
*The element concentration in Chuanlinggou Fm. is not shown, because the contents of its trace elements are all less than the Clarke rock values.
82
dized zone. The average organic carbon content in light chambersites is 2.24% and the average Eh value of 32 wall-rock samples is - 3 8 6 . 5 m v (Huang Xueguang, 1983). The Mn occurrences in the Tieling Formation are partly related t o manganese-hearing stromatolitic dolomite of neritic facies. The crystal lattices of Mg ++ in dolostone are c o m m o n l y occupied by Fe ++ and Mn ++. There are also some manganosiderite occurrences which probably formed in weakly reducing conditions. Manganiferous beds are present throughout the whole Yanshan Basin. The element concentrations in each formation are shown in Table II. CHEMOSTRATIGRAPHIC YANSHAN SEDIMENTARY
CORRELATIONS BASINS
BETWEEN
THE
SHENNONGJIA
AND
Late Precambrian Systems are well developed m the Shennongjia region and provide possibilities for correlation of late Precambrian strata in North China with equivalents in South China. On the basis of chemostratigraphic studies (Fig. 3) the Shennongjia Group can be subdivided into three subgroups and 11 formations. Subgroup boundaries are based on the optimal section technique. Other sedimentary breaks occur between these major subdivisions. The three subgroups can be correlated with the Changcheng, Jixian and Qingbaikou Systems, respectively, of the Jixian section. The boundary between the Shennongjia Group and the Sinian System is taken as the b o u n d a r y between the Macaoyuan and Liantuo Fins. The Macaoyuan Fro. comprises regressive sediments such as rapidly deposited carbonate-rich conglomerates, volcanic rocks and dolomites. The important elements are Mn, Ti, Fe, K, Cr etc. Marine carbonates are well developed in the Shennongjia Gp. Dolomites are predominant, making up 70% of the total thickness (78% in the Jixian section). Statistical studies show that Ca/Mg ratios of these carbonate cycles have the same characteristics as those of the Jixian section (Fig. 4). In both sections Ca/Mg ratios are slightly :> 1. This agrees with the theoretical value for dolomite. According to data from X-ray and chemical analyses, carbonate minerals from the Jixian section mostly have Mg/Ca ratios of a b o u t 1, so that the dominant mineral is probably disordered
Fig. 3. Synthetic chart of the chemostratigraphy of the middle and upper Proterozoic of the Shennongjia region, Hubei. A. The line of Optimal Section, the numbers indicate the grade of the Optimal Section; B. Indicator elements of chemical boundaries; C. Typomorphic element of each formation; D. The result of time Series concerning element ratios (1,2 indicate the curves of the primary content; 1'2' indicate Digital Filter curves; E. Trace elements; F. Organic carbon and carbon dioxide; G. p H value; H. Eh value; I. The curve of orgmfic carbon content, the direction of left arrow shows increRJi~ trend of organic carbon. The curve of CO2 content, the direction of right arrow shows increasing trend of COs; a. Dayanping Fro.; b. Luanshigou Fro.; c. Dawokeng Fro.; d. Kuangshishan Fro., e. Taizi Fro.; f. Yiemahe Fro.; g. Wenshuihe Fro.; h. Shicaohe Fro.; i. Songziyuan Fro., j. Wagangxi Fro.; k. Macaoyuan Fro.; I. Liantuo Fro.; m. Nantuo Fro.; n. Doushantuo Fm.; o. Dengying Fro.; p. Shlhaoping Fro.
!
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:
Protet~o~oic
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84 Ca/Ms 2o~
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1 ,
A
~-
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I 2. A;
~n
T3. ~4, T........... B ~
s
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17' ; C ~--
Fig. 4. Histogram of Ca/Mg ratios in carbonate strate. Aa=The Changcheng System; Ba= The dixian System; Ca=The Qingbaikou System; la=Dahongyu Fm.; 2a=Tuaashanzi Fm.; 3a=Gaoyuzhuaag Fro.; 4a=Ya~zhuaag Fro.; 5a=Wumiahan Fro.; 6a=Tieliag Fm.; 7a= Jingeryu Fro.; Ab=Lower Subgroup of the Shetmongjia Group; Bb=Middle Subgroup of the Shennongjia Group; cb=Upper Subgroup of the Shennongjia Group; lb=Luanshigou Fm.; 2bfDawokeng Fro.; 3bfKuang~Imn Fm.; 4bfTaizi Fro.; 5bfYiemahe Fro.; 6b= Wenshuihe Fro., 7bfShicaohe Fro.; 8b=Wangangxi Fro.
dolomite. Those in which the Mg/Ca ratios are not 1 (only a few samples) could be Ca-rich dolomites, ferruginous dolomites, Mg-rich calcites etc. We have compared data on Ca/Mg ratios of Precambrian and Palaeozoic carbonates (Qin Zhengyong et al., 1984). Ca/Mg ratios in the Proterozoic are a b o u t 1 whereas Ca/Mg ratios from Archaean and Palaeozoic rocks are > 10. Red beds of the Shennongjia area provide a good marker for correlating the Shennongjia Group with middle and upper Proterozoic rocks of the Yanshan region. They are distributed in the Jixian System and Shennongjia Group; e.g., the Yangzhuang, Wumishan, Chuanlinggou, Shicaohe Fro., Wenshuihe, Yiemahe, and Luanshigou Fins. The red beds are rich in K, Co, V, Zr, Ba, Ni, and Ti. Enrichment o f U in Proterozoic red beds in Canada has b e c o m e an important energy resource. Proterozoic red beds in China are rich in Ba, K, gypsum, halite casts etc. According to palaeomagnetic data the Yangzhuang Fro. formed at a palaeolatitude of a b o u t 34 ° (Liu Chun et al., 1979). It was 19 ° for the Shicaohe Formation (Zhang Huimin et al., 1984). All of these formations lay in middle latitudes during the Precambrian. To some degree the red beds appear to reflect an important worldwide event. They probably formed in a hot and possibly damp climate. Such red beds have long been used as large scale stratigraphic markers, e.g., the Palaeozoic and Mesozoic eras. The oldest red beds may be in the Dharwar greenstone belts of India (c. 2500 Ma). The second major period of red bed occurrence is between about 1800 and 2000 Ma ago and includes such red beds as the Waterburg Group o f South Africa (1800--2000 Ma) and the Aphebian o f Canada (2100--2300 Ma). The red beds in the Luar~shigou Fro. o f the Shennongjia Group and Chuanlinggou Fro. of the Changcheng System m a y also have been produced in this period. The third period is a b o u t 1300--1400 Ma ago. The red beds of the Yangzhuang Fro. and the Shicaohe Fro. may belong to this period. Some elements appear to reflect the geochemical environment of the sedimentary basins and can be used to correlate times of ore-genesis in geological history. The Changcheng System is rich in Fe and K', the Jixian System in Ba, Fe, Cu, Si, C and Pb; the Qinbaikou System, in Fe and Cu.
85 T h e f a m o u s X u a n l o n g - t y p e iron ore o f the Y a n s h a n region is in the Changc h e n g S y s t e m . T h e r e are also significant r e s o u r c e s in t h e J i x i a n S y s t e m , e.g., m a n g a n e s e c a r b o n a t e - - m a n g a n e s e o x i d e s in t h e J i x i a n S y s t e m w i t h an age o f a b o u t 1 5 0 0 - - 1 4 0 0 Ma, G a o b a n h e lead-zinc ore, Wafangzi m a n g a n e s e ore (c. 1 0 0 0 Ma), c o p p e r ore in the S h i c a o h e F m . and uvanite in the Taizi F o r m a t i o n o f the S h e n n o n g j i a G r o u p . T h e r e is l e a d - - z i n c ore, p y r i t e , coal etc. in the G a o y u z h u a n g F m . in the Y a n s h a n R a n g e a n d the organic c a r b o n c o n t e n t in the Taizi, Wunshihe and S o n g z i y u a n F m s . is as high as 0 . 4 3 - 6.16%. The average c o n t e n t o f a m i n o acid in t h e s e f o r m a t i o n s is 5 . 8 9 - 13.47 X 10 -3 ~ m g-i (Qin Z h e n g y o n g et al., 1984). T h e figures f r o m t h e Jixian section are 4 0 - - 5 0 X 10 -3 /~m g-1 ( C h e n G u a n g z h o n g et al., 1981}. All o f t h e s e d a t a suggest b i o c h e m i c a l i n f l u e n c e o n s e d i m e n t a t i o n . S u l p h u r i s o t o p e s in m a r i n e s u l p h a t e are c o m m o n l y c o n s i d e r e d to be unif o r m on a w o r l d - w i d e basis f o r a given p e r i o d o f geological t i m e . T h e evolution o f s u l p h u r i s o t o p e s has b e e n said to reflect global t e c t o n i c p r o c e s s e s ( L a m b e r t et al., 1983). T h e r e is clear e v i d e n c e o f i s o t o p i c f r a c t i o n a t i o n in the S h e n n o n g j i a G r o u p . T h e values o b t a i n e d f r o m the S h e n n o n g j i a G r o u p can be c o m p a r e d w i t h biological s u l p h u r , m o d e r n sea w a t e r s u l p h u r and s u l p h u r f r o m e v a p o r i t e s {Fig. 5). T h e 534S values f r o m the D a y a n p i n g F o r m a t i o n { > 1 6 0 0 Ma), as i n d i c a t e d b y Qin Z h e n g y o n g ( 1 9 8 4 ) is + 1 5 . 6 2 -1 9 . 8 7 o / o o . This value is similar to t h a t o f m o d e m m a r i n e sulphur. T h e G a o y u z h u a n g F m . ( 1 5 0 0 - - 1 6 0 0 Ma) has 534S values m a i n l y in the range o f - 1 3 - - +24 o / o o . T h e 534S values f r o m t h e Taizi F o r m a t i o n range f r o m
F"T"~ s
I ;','',',~,'; ~ " " y ~, ~ ." ~,.~.>~\'~.,"" . :TY/..
;
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111
1712 A
D E +40
-30
~20
~10
-10
20
30
-40
Fig. 5. The relative compositions of ~3~S in Precambrian strata of China and 5~S of known materials in nature. A=83"S of various materials in nature (adapted from Holser et al., 1966); I=Meteorite sulphur; II=Sulphur of modern sea-water; III=Biological sulphur; IV=Evaporite sulphate; B=8~4S in Precambrian strata, China; l=Wutai Group (+1.2 -+2.4% 0) (adapted from Li Shushan, 1980); 2=Dayanping Fro. of Shennongjia Group (.15.62 - +19.87% 0); 3=Taizi Fro. of Shennongjia Group (-0.26 -- +24.11% o); 4= Gaoyuzhuang Fm. of Jixian System (-13 -- +24"/o0) (adapted from Huang Xueguang, 1982); 5=Shicaohe Fm. {+18.91 -- *27.93%0 ) of Shennongjia Group.
86
:I o----___o2
,o
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5
~B
=~"~,
............. B~8~B5
I
I
I
I
I
-L
I
I
I
I
I
I
La
Ce
Pr
Nd
Sm
Eu
C.kl
Tb
Dy
14o
Er
Tm
I b
I
Lu
Fig. 6. Comparison of REE patterns of the middle and upper Proterozoic in Jixian and Shennongjia regions with the average Hutuo Group of the lower Proterozoic (Qin Zhengyong et al., 1984), the average Wutai Group of the Archaean (Qin Zhengyong et al., 1984), the average Proterozoic rocks of Australia (Taylor, 1979) and the average Archaean rocks in Greenland (Taylor, 1979). 1=The mid--upper Proterozoic in Shennongjia; 2=The mid--upper Proterozoic in Jixian; 3=The Hutuo Group of the lower Proterozoic in Wutai Mountain; 4=The Proterozoic of Australia; 5=The Atchaean Wutai Group in Wutai Mountain; 6=The Archaean in Greenland. TABLE Ill R E E d a t a i n p . p . m , foz t h e s e d i m e n t a r y r o c k s o f m i d d l e a n d u p p e r P r o t e r o z o t c i n J i x i a n S e c t i o n
La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu REE Eu/Eu* Y
1
2
3
4
5
6
7
8
9
10
11"
3.48 10.8 2.19 7.92 2.00 0.38 1.76 0.28 1.46 0.24 0.56 0.09 0.47 0.06 31.7 0.67 8.37
27.9 61.1 8.90 35.2 10.1 2.42 12.9 2.10 11.2 1.96 4.98 0.71 4.10 0.55 184 0.72 49.6
12.5 23.8 3.94 12.3 2.57 0.47 2.15 0.37 2.00 0.42 1.14 0.18 0.94 0.13 62.9 0.65 14.9
31.1 61.2 9.59 34.0 8.02 1.44 6.88 1.21 6.63 1.31 3.82 0.62 3.98 0.61 170 0.64 37.6
1.06 2.04 1.00 1.38 0.53 0.07 0.12 0.06 0.09 0.08 0.08 0.01 0.05 0.02 6.54 0.72 0.55
1.82 2.20 0.92 1.38 0.45 0.06 0.10 0.05 0.12 0.04 0.09 0.02 0.04 0.01 7.29 0.69 0.88
6.68 15.1 2.40 6.08 1.26 0.23 0.84 0.18 0.76 0.14 0.38 0.06 0.35 0.05 34.5 0.70 4.02
15.0 30.2 4.69 14,8 4.66 1.01 3.77 0.59 2.73 0.49 1.24 0.19 1.12 0.16 87.9 0.78 12.2
36.8 70.3 9.63 27.4 5.05 0.88 3.17 0.60 2.45 0.51 1.41 0.24 1.34 0.20 160 0.69 12.5
13.0 27.4 9.23 12.1 2.22 0.44 1.77 0.29 1.69 0.31 0.84 0.12 0.77 0.12 65.3 0.72 8.69
14.7 26.8 3.88 9.82 1.95 0.52 1.12 0.25 0.71 0.13 0.38 0.06 0.44 0.07 60.9 1.08 3.16
1. J i n s e r y u Fro. ( J ~ a u c o a / t / c s a n d s t o n e ) 2 . Xl-m-li*~_- F r o . ( s a n d y sha}e) 3. T / e l h ~ F r o . ( d o l o m / t e ) 4. H o n ~ h u / z h u s n 8 F i n . (silty s h a h ) 5. W ~ F r o . ( e h e r t y d o l o m i t e ) 6. Y a n z h u a n j F r o . (red siltbea~ng muddy dolosto~) 7. G a o y u z h u a n l F r o . ( m a n s a n o u s d o l o l t o n e ) 8. D a h o ~ y u F r o . (silty d o l o s t o n e ) 9. T u a n s h a n z i Fro. ( d o l o m i t l c s a n d s t o n e ) 1 0 . C " h u a n l i n g g o u Fro. (silty d o l o m i t e ) 11. Ch~Igzhousou Fro. (co~lomesate) * T h e Eravels i n t h i s c o n g l o m e r a t e s h o u l d b e t h e p r o d u c t o f a t e r r ~ e n o u s p r o v i n c e i n A r e h a u n ,
1.06 2.19 0.88 1.28 0.44 0.065 0.14 0.034 0.11 0.03 0.08 0.017 0.065 0.016 6.56 0.65 1.29
3.72 4.57 0.57 2.47 0.49 0.12 0.40 0.17 0.40 0.089 0.23 0.034 0.20 0.30 13,49 0.86 3.98
2
12.70 34.90 3.48 11.50 2.47 0.55 2.23 0.37 2.21 0.44 1,21 0.18 1.02 0.14 73.40 0.71 12.8
3 7.25 15.50 2.06 7.04 1.43 0.28 1.05 0.17 0.98 0.20 0.51 0.068 0.50 0.07 37.61 0.67 5.32
4 27.2 55.6 7.94 31.26 6.95 1.59 6.72 1.10 5.94 1.14 3.07 0.48 2.79 0.37 1.5209 0.7 28.8
5 4.5 6.14 1.07 4.21 0.97 0.21 0.81 0.19 0.79 0.17 0.41 0.066 0.32 0.043 19.90 0.7 6,56
6 12.30 22.9 3.38 13.3 2.77 0.60 2.38 0.41 1.93 0.38 1.03 0.14 0.84 0.12 62.48 0.7 14.20
7 41.90 84.8 10.6 34.5 6.49 1.52 4.43 0.77 3.56 0.68 1.82 0.29 1.64 0.23 193.23 0.82 7.10
8
A
3.58 38 5.44 80 0.78 8.9 3.18 32 0.66 5.6 0.15 1.1 0.56 4.7 0.11 0.77 0.59 4.4 0.12 1.0 0.29 2.9 0.025 0.41 0.23 2.8 0.027 0.4 15.74 183 0.75 0.64 5.34 27
9 19 38 4.3 16 3.7 1.1 3.6 0.66 8.7 0.82 2.3 0.32 2.2 0.3 97 1.0 22
B 9.5 17 2.0 8.0 2.8 1.1 3.1 0.58 3.4 0.73 2.0 0.28 1.9 0.25 54 1.1 20
C
1. Macaoyuan Fm. (dolostone with stromatolites) 2. Waganxi Fm. (stromatolitic reef dolostone) 3. Songziyuan Fm. (magnetite) 4. Shicaohe Fm. (red mud-bearing dolomite) 5. Wenshuihe Fro. (silty shale) 6. Taizi Fm. (dolomitic limestone) 7. Kuangshishan Fm. (silty dolomite) 8. Luanshigou Fm. (purplish-red siltstone) 9. Dayanping Fro. (silty dolostone) A.B.C.=Compositk)n of the post-Archaean continental crust (Taylor, 1979) (A. Upper crust B. Total crust C. Lower crust).
La Ce Pr Nd Sm Eu Gd Tb Dy Hu Er Tm Yb Lu REE Eu/Eu* Y
1
REE data in p.p.m, for the sedimentary rocks of the middle and upper Proterozoic in the Shennongjia Section
TABLE IV
Oo
12a
lla
9a
8a I_
6a
~
4a
3a
5a
....
la
E I~
~h
'-
Age
1950
1600
Orogeny
Fe203 red b e d
K.P
Mn.B.Pb Sr.stone coal K
Qin~ong uplifting
Volcanic activity
red b e d Ba g y p s u m
Fe.Mn
Fe
B
Luanxlan uplifting
ot~oleny
wuuae
Jixlan uplifting
A
1400
1200
I000
900
(Ma)
biological sulphur 5~'S - 1 3 to +24°/00
C
Lower
21
31
48
42
44
50
51
High
D
~ ~
E
i
~
llb
10b
9b
8b
7b
5b
4b
3b
2b
lb
12b >177o u (Ma)
~,
Q0
,~
~
g,
~!
Stratigraphic units
Orogeny
Volcanic activity
Volcanic activity
weathezlng crust
ancient
Gen]lng orogeny
A
red b e d
stone coal FezO 3
U.V
red b e d
Ba.Cu
Fe
B
to +19
°/oo
Sea w a t e r sulphur 5~S +15 t o +19
- 0 . 2 to +24°/00
biological sulphur 63'S
°/oo
+18
5~S
sulphur
Evaporation
C
ShennongJia region (miogeosyncline type)
2.'/ Lower
5.9
13.5
h/gh
D
E
A.Crtagal m o v e m e n t . B . T y p o c h e m i c a l e l e m e n t s , ore f o r m i n g e l e m e n t s a n d s e d i m e n t a r y f o r m a U o n . C . S u l p h u r i s o t o p e (°/o0). D . C o n t e n t of a m i n o acid (in 10 -~ # m / g ) . E . C h a r a c t e r l s t i c s of R E E . l a . J / n g e r y u Fro. 2 a . X l a m a l l n g Fro. 3a.Tiellng Fro. 4 a . H o n p h u l z u a n g F m . 5 a . W u m i s h a n Fro. 6 a . Y a n g z h u a n g F m . 7a. G a o y u z h u a n g Fro. 8 a . D a h o n g y u Fro. 9 a . T u a n s h a n z i Fro. 1 0 a . C h u a n l / n g g o u Fro. 1 1 a . C h a n g z h o u g o u Fm. 1 2 a . B a d a o h e and Q i a n x i Groups. l b . M a c a o y u a n Fro. 2b.Waganxi Fro. 3 b . S o n g z l y u a n Fro. 4 b ~ h l c a o h e Fro. 5 b . W e n s h u l h e Fro. 6 b . Y e m a h e Fro. 7 b . T a i z i Fro. 8 b . K u a n g s h i s h a n Fro. 9 b . D a w o k e n g Fro. 10b. L u a n s h / g o u Fro. 1 1 b . D a y a n p / n g Fm. 1 2 b . K o n g l / n g G r o u p .
,
Stratigraphic
y a n A h a n re8ton ( p l a t f o r m t y p e )
C h e m o s t r a t i g r a p h i c c o r r e l a t i o n of the m i d d l e a n d u p p e r P r o t e r o z o i c b e t w e e n Y a n s h a n a n d S h e n n o n g J l a s e d i m e n t a r y basins
TABLE V
00 0o
89
-0.26 -- +24 o/oo, similar to biological sulphur. The 53+S values from the Shicaohe Formation (c. 1400--1500 Ma) are all positive values (+18.91 +27.93 o/oo), similar to evaporitic sulphur. Compared with known natural evaporites with 63+S values ranging from +9 to +32 o/oo, this is a somewhat narrow spread, because the 834S values from evaporites of different geological periods differ somewhat. Generally the k n o w n range is from I o/oo to 4 o/oo. The 534S values from the Archaean Wutai Group of China (Li Shuxun, 1981) are +1.2 to +2.4 o/oo, close to the values of meteoritic sulphur. The preliminary data from the Precambrian of China suggest a progressive increase in 53"S values with decreasing age. Taylor and McLennan (1981a, b) and McLennan (1982) used REE pat~ terns to study the Archaean--Proterozoic boundary. We have also summarized REE data from the Chinese Precambrian (Tables III and IV). REE show a progressive increase in abundance from the Wutai Group and Hutuo Groups of the Archaean to the middle and upper Proterozoic. REE are more a b u n d a n t in clastic and clay-rich rocks than in carbonates. The REE in clastic and clay-rich rocks of the Proterozoic in Shennongjia and Jixian is close to upper crustal abundances (Taylor, 1979). The REE patterns, normalized to chondrites (Taylor et al., 1981c), in the Proterozoic of China including the Hutuo Gp. Changcheng System, Jixian System, Qingbaikou System and Sinian System (Fig. 6) show a rather steep curve with a distinct Eu anomaly. The Eu/Eu* ratio is 0.67--0.70. The Z REE is higher, about 40--60 ppm. The Z L R E E / Z H R E E ratio is about 8. These REE patterns are similar to those in post-Archaean sedimentary rocks of Australia. In contrast, the REE patterns of the Archaean Wutai Group differ from those of the Proterozoic. The patterns are gently inclined with no Eu anomaly.
100
SO
Z
c 9 20 \
TO
°L •
c~
~
Nd
i
I
Sm
E.
k
~
J
gb
~
L
~
,
L
Er
Tm
&
~
Lu
Fig. 7. R E E patterns from rocks of the Sinian System in the Shennongjia region, i= Nantuo Fro. (conglomeratic argillite);2= Dengying Frn. (siltshale).
90 T h e E u / E u * ratio is close to 1. T h e Z R E E is a b o u t 76 p p m and the ratio o f Z L R E E / Z H R E E is 9--11. T h e p a t t e r n s are similar to t h o s e o f the Arc h a e a n o f West Greenland. T h e R E E p a t t e r n s o f the Sinian S y s t e m show s t e e p l y inclined V-shaped curves (Fig. 7). T h e negative Eu a n o m a l y is very distinct and t h e E u / E u * ratio is b e t w e e n 0.59 and 0.65. These results are c o m p a r a b l e to R E E p a t t e r n s f r o m s e d i m e n t a r y r o c k s o f the A r c h a e a n in G r e e n l a n d and S o u t h Australia, the P r o t e r o z o i c in Australia a n d the H u r o n i a n S u p e r g r o u p o f C a n a d a ( M c L e n n a n et al., 1979). All o f t h e d a t a discussed a b o v e are s u m m a r i z e d in Table V. ACKNOWLEDGEMENTS
The a u t h o r s are greatly i n d e b t e d t o Prof. C h e n J i n b i a o and o t h e r colleagues w h o gave us help in these c h e m o s t r a t i g r a p h i c investigations. REFERENCES Chen Jinbiao, Zhang Huimin, Zhu Shixing and Zhao Zhen, 1980. Research on Sinian Suberathem of Jixisn, Tianjin. In: Research on Precarnbrian Geology -- the Sinian Suberathern in China. Tianjin Science and Technology Press, Tainjin, pp. 56--114 (in Chinese). Chen Haoshou, 1983. Lead and sulfur isotope studies of the stratabound polgmetallic deposits in China. Bull. Chin. Acad. Geol. Sci.,Miner. Dep., 2:79--87 (in Chinese). Holser, W.T. and Kaplan, I.R., 1966. Isotope geochemistry of sedimentary sulfates. Chem. Geol., 1: 93-135. Kishicia, A. and Ricco, L., 1980. Chernogeratigraphy of lava sequences from the Rio Itapicurn Greenstone Bashi State Brazil. Precambrian Res., 11: 161--178. Lambert, I.B. and Donnelly, T.H., 1983. Implications of Precambrian sulfur isotope compositions. In: International symposium on late Precarnbrian geology, Tainjin, Organizing committee for the I.S.L.P. and Chinese Acad. Geol. Sci., pp. 75--76. Leinen, M., Heath, G.R. and Muratli, C., 1980. Chemical stratigraphy and paleoenvironrnent of Cenozoic north Pacific sediments. EOS, Am. Geophys. Union, Trans., 61: 257. McLennan, S.M., 1982. On the geochemical evolution of sedimentary rocks. Chem. Geol., 37: 335--350. McLennan, S.M., Fryer, B.J. and Young, G.M., 1979. The geochemistry of the carbonaterich Espanola Formation (Huronian) with emphasis on the rare earth elements. Can. J. Earth Sci., 16: 230--239. McLennan, S,M., Fryer, B.J. and Young, G.M., 1979. Rare earth elements in Huronian (Lower Proterozoic) sedimentary rocks: composition and evolution of the postKenoran upper crust. Geochim. Cosrnochirn. Acta, 43: 375--388. Nanee, W.B. and Taylor, S.R., 1976. Rare earth patterns and crust evolution I: Australia post-Archean sedimentary rocks. Geochirn. Cosrnochim. Acta, 40: 1539--1551. Qin Zhengyong, 1980. A preliminary study on geochemistry of the Sinian Suberathern in the Yanahan range, North China. In: Scientific Papers on Geology, Beijing, pp. 75--84 (in Chinese). Qin Zhengyong, Cheng Meiqi, Yang Xiuen and Du Tangzhi, 1984. The model of chernostratigraphy in Proterozoic China. In: Scientific Papers on Geology, Beijing, pp. 179--194 (in Chinese). Sversensky, D.A., Ryre, D.M. and Doe, B.R., 1979. The lead and sulfur isotopic compositions of galena from a Mimisippi valley-type deposit in the new lead belt, southeast Missouri. Econ. Geol., 74: 149--253.
91 Taylor, S.R., 1979. Chemical composition and evolution of the continental crust: the rare earth element evidence. In: M.W. McElhinny (Editor), The Earth: Its Origin, Structure and Evolution, Academic Press, London, pp. 353--376. Taylor, S.R. and McLennan, S.M., 1981a. The rare earth element evidence in Precambrian sedimentary rocks: implications for crustal evolution. Precambrian Plate Tectonics, pp. 530--536. Taylor, S.R. and McLennan, S.M., 1981b. The composition and evolution of the continental crust: rare earth element evidence from sedimentary rocks. Philos. Trans. R. Soc. London, Ser.A: 301: 381--391. Taylor, S.R. and McLennan, S.M., 1981c. Rare earth element evidence for the chemical composition of the Archaean crust. Geol. Soc. Aust. Spec. Publ., 7 : 255--261. Turner, P., 1980. Continental red beds. Develop. Sedimentaol., 29 : 1--66. Wang Yuelun, Lu Zongbin, Xing Yusheng, Gao Zhenjia, Lin Weixing, Ma Guogan, Zhang Luyi and Lu Songnian, 1980. Subdivision and correlation of the Upper Precambrian in China. In: Research on Precambrian Geology -- the Sinian Suberathem in China. Tianjin Science and Technology Press, Tianjin, pp. 1--30 (in Chinese). Yamamoto, S., Honjo, S. and Merriam, D., 1978. Quantitative chemical stratigraphy of the Nio Brara Chalk (Cretaceous) in western Kansas. Comput. Geol., 3 : 2 3 5 244. Zhang Huimin and Zhang Wenzhi, 1984. Middle and Upper Proterozoic magnetostratigraphy and tectonic evolution in Eastern China. In: Scientific Papers on Geology. Beijing, pp. 150--161 (in Chinese). Zhang Wenzhi and Li Pu, 1980. Palaeomagnetism of the Sinian Suberathem in the Jixian, China. Bull. Chin. Acad. Geol. Sci., Set. 4, 1 : 1 1 1 - - 1 2 2 (in Chinese). Zhao Zigiang, Xing Yusheng, Ma Guogan, Yu Wen and Wang Ziqiang, 1980. The Sinian System of eastern Yangtze, Hubei. In: Research on Precambrian Geology - the Sinian Suberathem in China. Tianjin Science and Technology Press. Tianjin, pp. 31--35 (in Chinese).
77
CHEMOSTRATIGRAPHIC CORRELATION OF THE MIDDLE AND UPPER PROTEROZOIC BETWEEN THE YANSHAN AND SHENNONGJIA BASINS
QIN ZHENGYONG', YANG XIUEN 2 and JIANG MINGMEI' ' Tianjin Institute o f Geology and Mineral Resources, Chinese Academy o f Geological Sciences, Tianjin 300170 (People's Republic o f China) 2Geological Bureau o f Hubei Province, Wuhan. Hubei (People's Republic o f China) (Received May 16, 1984; revision accepted September 1, 1984)
ABSTRACT
Qin, Z., Yang, X. and Jiang, M., 1985. Chemostratigraphic correlation of the middle and upper Proterozoic between the Yanshan and Shennongjia Basins. Precambrian Res., 29: 77--91. This paper is concerned with the distribution of major elements, transition elements, REE, sulphur isotopes and organic carbon in parts of the Proterozoic of China. Lithophile and ore-forming elements such as Ba, Sr, Mn, K, V, Fe and Cu are good chemical markers and are used for correlation in the Yanshan Basin. The Ba content is particularly high in red beds of several sections. Ba, Fe, K, Mn, V, Ca, Mg and organic carbon have provided useful data for correlation between the Yanshan and Shennongjia Basins. These elements reflect, in varying degree, widespread important geological events. We propose several chemostratigraphic stages with divisions approximately at 1950 Ma, 1600 Ma, 1200 Ma and 1000 Ma. These divisions correspond approximately to major time boundaries in the Proterozoic of China. 83"S values for sulphur isotopes in Proterozoic strata in China are between - 1 3 o/oo and + 27 o/oo. REE patterns, normalized to chondritic abundances, for middle--upper Proterozoic rocks of China, are similar to post Archaean sedimentary rocks of Australia. They also show Eu depletion and Eu/Eu* ratios between 0.6 and 0.8.
INTRODUCTION In C h i n a c h e m o s t r a t i g r a p h i c t e c h n i q u e s have b e e n u s e d in s t u d i e s o f m i d d l e a n d u p p e r P r o t e r o z o i c s t r a t a o f t h e J i x i a n s e c t i o n since 1974. In 1979 we used these m e t h o d s for subdivision of stratigraphic successions. The major elements, transition elements, rare earth elements, stable isotopes etc. in s e d i m e n t a r y r o c k s p r o v i d e m u c h u s e f u l i n f o r m a t i o n r e l e v a n t t o t h e g e o c h e m i c a l e n v i r o n m e n t a n d r e c y c l i n g a n d d i s t r i b u t i o n o f e l e m e n t s in t i m e a n d s p a c e . T h e g o a l s o f s u c h s t u d i e s are s u b d i v i s i o n a n d c o r r e l a t i o n a n d t o a p p r o a c h an u n d e r s t a n d i n g o f t h e e v o l u t i o n o f t h e a t m o s p h e r e , h y d r o s p h e r e a n d l i t h o s p h e r e . In t h i s p a p e r t h e c h e m i c a l a p p r o a c h is u s e d t o a t t e m p t correlation of middle and upper Proterozoic sediments within and between s e d i m e n t a r y b a s i n s in S o u t h a n d N o r t h C h i n a . 0301-9268/85/$03.30
© 1985 Elsevier Science Publishers B.V.
78 CHEMOSTRATIGRAPHIC CORRELATION BASIN O F N O R T H C H I N A
IN
THE
YANSHAN
SEDIMENTARY
Rock samples from five sections of the Yanshan Basin, including the Pangjiapu, Qinlingshan and Yanmenzi, in Hebei Province, Changping Ming Tombs and Jixian County in Tianjin (Fig. 1) have been systematically collected and analysed by the following methods: complete mineral and rock analyses, atomic absorption spectrometry, polarography and laser microprobe analyses. The data were then mathematically analysed using a computer. • ~etioo location ~ , ~ ~rata o f k~ddl¢ and Upper Proterozol¢
/ y /r~,~ ~',~ v - , - ~ ' ~ ~(.L.,"~ x'''~'- ~ • .. "f \
f
~ ~, L,J
~ -
~ t~(,tT:,,. ~ / hi:." ~/.'.,,' ~
,'
,,,,,,,~,;
~"
,:~(]
~
~ ~
.tr..
,~
'
~
..r.
t.Z.Y"
::" ........ •
',
,,r> rA.D ,KT,
, ~,
.,"~ L O"S/: ' "
...
• '
"
~
,j
~ ~..
-:~S ..... o_..~.~ ._
~,
' << " :~- ": :" " . . ...' i.. ' . . ; . : ~ . ,
~. : .: / " , \ ".~.../::..;x ~ " . . ..;. :. • / .' . . " . ~." ~m-z_s-.
'"
''.-JY"-
t-"<....~
, ~ . , P~-~-> ;.
,,,,,
. ~::~
,,?~:
~
:
o
Fig. 1. A s k e t c h m a p s h o w i n g a p p r o x i m a t e l o c a t i o n s o f s e c t i o n s o f t h e m i d d l e and u p p e r P r o t e r o z o i c in t h e Y a n s h a n region, China. l = X u a n h u a Pangjiapu; 2=Changping
Ming Tombs; 3=TianjinJixian; 4=Luanxian Qinglongshan; 5=KuanchengYamenzi. The middle and upper Proterozoic of the Jixian stratotype section was subdivided into five geochemical cycles, four systems and 14 formations by Qin Zhengyong et al. (1980). Based on chemostratigraphic data a new scheme of subdivision is suggested in this paper (Table I). An important chemical stage (c. 1600 Ma ago) is shown by a break at the base of the Gaoyuzhuang Formation. This break corresponds approximately to a global orogeny about 1500--1600 Ma ago. Chen Jinbiao et al. (1982) considered this to be the boundary between the middle and upper Proterozoic. The other boundary (c. 1000 Ma) is placed between the Qingbaikou and Yuyang chemical stages, so that the base of the Qingbalkou System is still placed at the ancient weathering surface of the Xiamaling Formation. The 1000 Ma event is probably of global significance. Three obvious lines of subdivision, based on major element chemistry, are shown in Fig. 2. The first is at the contact between the Dahongyu and Gaoyuzhuang Formations. Its values vary from 2 to 3. The second one, representing the boundary between the Wumishan and Hongshuizhuang Formations, ranges from 3 to 7 and the third boundary, between the Changzhougou and Chuanlinggou Formations has values ranging from 4 to 6. The
Fujunshan Fm.
Changzhougou Fm.
Chuanlin$$o u Fm.
Tuanshanzi Fm.
D a h o n g y u Fro.
G a o y u z h a n g l,'m.
Y a n g z h u a n g Fro.
W u m i s h a n Fro.
H u n g s h u i z h u a n g Fro.
Tieling Fro.
X i a m a l i n g Fro.
Jingeryu Fm.
~
8
relation of Jixian Section
Contact
0
0
Contact relation o f regional s e c t i o n
1900
1700
1600
1400
1200
1000
900
Age (Ma)
Chemical stage of Changcheng
Chemical stage o f Jixian
Chemical stage of Yuyang
Chemical stage o f Qingbaikou
Chemical stage
T h e first subcycle
The second subcycle
"l~e first subcycle
The s e c o n d subcycle
The first cycle
The first subcycle
The s e c o n d sub cycle
T h e s e c o n d cycle
The third cycle
The f o u r t h cycle
T h e fifth cycle
G e o c h e m i c a l cycle
~
~
C ~
C
B ~
I
D
J
H
K
A
m, E
L
K
w O
w F
,at........_ v E
H ~
I
I
E
C
I,' ~ - ~
*Lithological characteristics o f e v e r y cycle
U n d e r l y i n g strata: Qianxi G r o u p o f A r c h a e a n A - - C o n g l o m e r a t e r o c k ; B - - q u a r t z i t e ; C - - s a n d s t o n e ; I > - g l a u c o n i t i c s a n d s t o n e : E - s i l t y shale, I,'- shale: G - - l i m e s t o n e ; H - - d o l o m i t i c l i m e s t o n e , I-Lime d o l o m i t e ; J - d o l o m i t e ; K - - a r g i l l o a r e n a c e o u s c a r b o n a t i t e . *The d a t a were p u b l i s h e d b y Qin Z h c n y o n g ( 1 9 8 0 ) in a p r e l i m i n a r y s t u d y on the g e o c h e m i s t r y of the S i m a n S u b e r a t h e m in the Y a s h a n R a n g c , N o r t h China.
Changcheng System
Jixian System
Qingbalkou System
Lower Cambrian
L i t h o s t r a t i g r a p h i c units
B o u n d a r i e s and geochemical environments
C h e m o s t r a t i g r a p h i c s u b d i v i s i o n for the m i d d l e and u p p e r P r o t e r o z o i c in J i x i a n S e c t i o n
TABLE I
+
3
'
I
;
I
~*'
~
o
~
..-
..'~.._
A
~o
~.
..............
......
. . . . . . . . . . . . . . . . . . . . . .
-~,
i
_ , ~_,, i_.~
- - .7 r- -3
;--" ~-,I
-_
1 7 - ~ ( !
--9
,,i
.
.:,.
~
" .
.
Fe2t')3
.
Y
.
.
TiO2
K20
Nard
"\
. . ). i
/
P2Os
)i~ ~
~o
2's ~ -~:5 ~--0-~
/ I
~*~-
/
MnO
~
*
•-
v
II
o'-4 "~
o'.j -'~
~--~."~I~. ~'~~~ "~~ .:....~.~..... ....
MgO
o o.s ) 1,s 2 o i . . 2. . . 3 ~ ~ 0J, 0., 0 0.1 0.~ 0!~ 01, 6 0t2 0',-0'.e 0~ i' Fig. 2, Optimal Section boundaries and curves of oxide contents in sections of Yanshan sedimentary basin. A=Changping Ming Tombs; B=Jixian County; C=Yamenzi, Hebei Province; D=Qinlongshan, Hebei Province; a=Changzhougou Gin.; b=Chuanlinggou Fm.; c= Tuanshanzi Fm.; d=Dahongyu Fro.; e=Gaoyuzhuang Fro.; f=Yangzhuang Fm.; g=Wumishan Fro.; h=Hongshuizhuang Fro.; i=Tieling Fm.; j=Xiamaling Fro.; k=Jingeryu Fro.; Key. I=Jixian section; II=Ming Tombs section; III=Yamenzi section; IV=Qinlongshan section; V=Optimal Section grade.
L
,.,
. . . . . . .I
,- ....
;
-,~-.
^ ! '- ~:I
io-~-'--~
,,.
I ~ d- . . . .
,--~-.-
i-- k
r.....
---~- ~
-
Oo O
81 major element compositions are obviously different above and below these boundaries. The Gaoyuzhuang, Yangzhuang and Wumishan Formations are mainly composed of dolomite, probably formed under weakly alkaline conditions (pH 8--9) at about 10 ° of palaeolatitude. The Hongshuizhuang and Jingeryu Formations consist of mudstone, limestone and siliceous dolostone. These rocks probably formed in neutral--weakly alkaline environments (pH 7--8). The Changzhougou Formation is mainly terrigenous fluvial deposits with very different geochemical characteristics from those of the mudstones and carbonates of the other units. The mean values for 13 elements and Clarke concentration values (ratios of these values to the corresponding Clarke values) show t h a t there is a systematic distribution of elements such as Ba, Sr, Mn, V, Fe and Cu. For example, the Ba ratio in the Jixian System, which is mainly carbonates, is >1. In particular Ba reaches its greatest concentrations with ratios of 13--40 in the Yangzhuang Formarion at several sections. These values were probably palaeochmatically controlled. In the Yangzhuang Formation of the Yanshan Basin Ba-rich red beds could have formed in a hot (and possibly humid) climate. Such red beds are c o m m o n l y used for correlation in this region. Most Sr values are lower than the Clarke values. Dolomitization may have been largely responsible for Sr depletion for when Mg replaced Ca during this process Sr was probably also lost. Based on Mn distribution we think that the Gaoyuzhuang Formation was deposited in the reducing, somewhat restricted environment of a rehct sea. There are two occurrences of Mn ore in the Gaoyuzhuang Formation of Jixian County. One is chambersite in deeper locations and the other is pyrolusite and psilomelane in association with pyrite and galena in the oxiTABLE II Important elements in sections of the Yanshan region Lithostratigraphic units
Elements
Qingbaikou System
Jingeryu Fm. XiamalingFm.
Ni.Cr.CoMln.Ba.Ti.V.Zr. V.Mn.
Jixian
Tieling Fm. Hungshuizhuang Fm. Wumishan Fm. Yangzhuang F r o . Gaoyuzhuang Fro.
Mn.Ba.Zr. Zr.V. Cu .Ba. Cu.Ba.Ti.Zr. Cu.BaMIn.Zr.Cr.
System
Changcheng System
Dahongyu Fm. Tuanshanzi Fm. *Chuanlinggou Fro. Changzhougou Fro.
V.Co.Ba.Ti.Zr.B.Co.Mn.Cu. V.Cr.Ba.Ti.B.Ni.Co.Cu.Zr. Mn.V.Ni.Co.Cu.
*The element concentration in Chuanlinggou Fm. is not shown, because the contents of its trace elements are all less than the Clarke rock values.
82
dized zone. The average organic carbon content in light chambersites is 2.24% and the average Eh value of 32 wall-rock samples is - 3 8 6 . 5 m v (Huang Xueguang, 1983). The Mn occurrences in the Tieling Formation are partly related t o manganese-hearing stromatolitic dolomite of neritic facies. The crystal lattices of Mg ++ in dolostone are c o m m o n l y occupied by Fe ++ and Mn ++. There are also some manganosiderite occurrences which probably formed in weakly reducing conditions. Manganiferous beds are present throughout the whole Yanshan Basin. The element concentrations in each formation are shown in Table II. CHEMOSTRATIGRAPHIC YANSHAN SEDIMENTARY
CORRELATIONS BASINS
BETWEEN
THE
SHENNONGJIA
AND
Late Precambrian Systems are well developed m the Shennongjia region and provide possibilities for correlation of late Precambrian strata in North China with equivalents in South China. On the basis of chemostratigraphic studies (Fig. 3) the Shennongjia Group can be subdivided into three subgroups and 11 formations. Subgroup boundaries are based on the optimal section technique. Other sedimentary breaks occur between these major subdivisions. The three subgroups can be correlated with the Changcheng, Jixian and Qingbaikou Systems, respectively, of the Jixian section. The boundary between the Shennongjia Group and the Sinian System is taken as the b o u n d a r y between the Macaoyuan and Liantuo Fins. The Macaoyuan Fro. comprises regressive sediments such as rapidly deposited carbonate-rich conglomerates, volcanic rocks and dolomites. The important elements are Mn, Ti, Fe, K, Cr etc. Marine carbonates are well developed in the Shennongjia Gp. Dolomites are predominant, making up 70% of the total thickness (78% in the Jixian section). Statistical studies show that Ca/Mg ratios of these carbonate cycles have the same characteristics as those of the Jixian section (Fig. 4). In both sections Ca/Mg ratios are slightly :> 1. This agrees with the theoretical value for dolomite. According to data from X-ray and chemical analyses, carbonate minerals from the Jixian section mostly have Mg/Ca ratios of a b o u t 1, so that the dominant mineral is probably disordered
Fig. 3. Synthetic chart of the chemostratigraphy of the middle and upper Proterozoic of the Shennongjia region, Hubei. A. The line of Optimal Section, the numbers indicate the grade of the Optimal Section; B. Indicator elements of chemical boundaries; C. Typomorphic element of each formation; D. The result of time Series concerning element ratios (1,2 indicate the curves of the primary content; 1'2' indicate Digital Filter curves; E. Trace elements; F. Organic carbon and carbon dioxide; G. p H value; H. Eh value; I. The curve of orgmfic carbon content, the direction of left arrow shows increRJi~ trend of organic carbon. The curve of CO2 content, the direction of right arrow shows increasing trend of COs; a. Dayanping Fro.; b. Luanshigou Fro.; c. Dawokeng Fro.; d. Kuangshishan Fro., e. Taizi Fro.; f. Yiemahe Fro.; g. Wenshuihe Fro.; h. Shicaohe Fro.; i. Songziyuan Fro., j. Wagangxi Fro.; k. Macaoyuan Fro.; I. Liantuo Fro.; m. Nantuo Fro.; n. Doushantuo Fm.; o. Dengying Fro.; p. Shlhaoping Fro.
!
....
Shennong]ia i
:
Protet~o~oic
Erathem Sinian
Group
_~_~_
. . . . .
i
=
L L L
L
L
L
L
_L
=
- - - r ........ System
.-_-:.----W~--=.
..I_.,~L L
" L
L
L
t t.
L L
k L . . . . . .
L
t
l/alaeo~oic ~' J Erathem ...... ~' Cambrian ,-: ~.
L__-
....
~. L L
L
;~
~ I :
.... ~.
L L
L
[ L
k
System-
--!=r-r
Iii
L L L L
L
k L
L L
I-~°! °':,;
L
L t. k
L L L
L L
.....
U L L L L
L_
L
k
I ~
._
I ........ _-
i"
7 -
,~.
,I
_1
v
•
=
,~
.__. ¢3
-'i = ......
_i-
~
i- ....
~
f
~ C~
"-
'. . . . . . . .
"W Y
tm
ro
............ . . . . . . . . . . . . . . . . . . . . . .
.~j~k,.-.,\
" " ~~j ~J ~,~.,
-........... -7.
.............
/
--
.
/~-
.... ~
~,,'..& %
~
~
. . . . .
_
- .....
~-~.l~u_~
I o
.§ B~
"\.~ . ~i'.- , ~ i .~!.i !~
_ ~I . ~':'
,,
!,' I' ,~ 'J ',, ~' ',,~,,,.A. i: wv -,.~ ,,,. D; '
p, / ,~,,,m~ _
/~,
, -: "'~--
,,',~
~ ~
i/
',
,,
-°
~, :.i~ I
"
84 Ca/Ms 2o~
Sh~nnon~
~n
17-2
yana~n
1 ,
A
~-
B .......
~c - J
I 2. A;
~n
T3. ~4, T........... B ~
s
J_s
17' ; C ~--
Fig. 4. Histogram of Ca/Mg ratios in carbonate strate. Aa=The Changcheng System; Ba= The dixian System; Ca=The Qingbaikou System; la=Dahongyu Fm.; 2a=Tuaashanzi Fm.; 3a=Gaoyuzhuaag Fro.; 4a=Ya~zhuaag Fro.; 5a=Wumiahan Fro.; 6a=Tieliag Fm.; 7a= Jingeryu Fro.; Ab=Lower Subgroup of the Shetmongjia Group; Bb=Middle Subgroup of the Shennongjia Group; cb=Upper Subgroup of the Shennongjia Group; lb=Luanshigou Fm.; 2bfDawokeng Fro.; 3bfKuang~Imn Fm.; 4bfTaizi Fro.; 5bfYiemahe Fro.; 6b= Wenshuihe Fro., 7bfShicaohe Fro.; 8b=Wangangxi Fro.
dolomite. Those in which the Mg/Ca ratios are not 1 (only a few samples) could be Ca-rich dolomites, ferruginous dolomites, Mg-rich calcites etc. We have compared data on Ca/Mg ratios of Precambrian and Palaeozoic carbonates (Qin Zhengyong et al., 1984). Ca/Mg ratios in the Proterozoic are a b o u t 1 whereas Ca/Mg ratios from Archaean and Palaeozoic rocks are > 10. Red beds of the Shennongjia area provide a good marker for correlating the Shennongjia Group with middle and upper Proterozoic rocks of the Yanshan region. They are distributed in the Jixian System and Shennongjia Group; e.g., the Yangzhuang, Wumishan, Chuanlinggou, Shicaohe Fro., Wenshuihe, Yiemahe, and Luanshigou Fins. The red beds are rich in K, Co, V, Zr, Ba, Ni, and Ti. Enrichment o f U in Proterozoic red beds in Canada has b e c o m e an important energy resource. Proterozoic red beds in China are rich in Ba, K, gypsum, halite casts etc. According to palaeomagnetic data the Yangzhuang Fro. formed at a palaeolatitude of a b o u t 34 ° (Liu Chun et al., 1979). It was 19 ° for the Shicaohe Formation (Zhang Huimin et al., 1984). All of these formations lay in middle latitudes during the Precambrian. To some degree the red beds appear to reflect an important worldwide event. They probably formed in a hot and possibly damp climate. Such red beds have long been used as large scale stratigraphic markers, e.g., the Palaeozoic and Mesozoic eras. The oldest red beds may be in the Dharwar greenstone belts of India (c. 2500 Ma). The second major period of red bed occurrence is between about 1800 and 2000 Ma ago and includes such red beds as the Waterburg Group o f South Africa (1800--2000 Ma) and the Aphebian o f Canada (2100--2300 Ma). The red beds in the Luar~shigou Fro. o f the Shennongjia Group and Chuanlinggou Fro. of the Changcheng System m a y also have been produced in this period. The third period is a b o u t 1300--1400 Ma ago. The red beds of the Yangzhuang Fro. and the Shicaohe Fro. may belong to this period. Some elements appear to reflect the geochemical environment of the sedimentary basins and can be used to correlate times of ore-genesis in geological history. The Changcheng System is rich in Fe and K', the Jixian System in Ba, Fe, Cu, Si, C and Pb; the Qinbaikou System, in Fe and Cu.
85 T h e f a m o u s X u a n l o n g - t y p e iron ore o f the Y a n s h a n region is in the Changc h e n g S y s t e m . T h e r e are also significant r e s o u r c e s in t h e J i x i a n S y s t e m , e.g., m a n g a n e s e c a r b o n a t e - - m a n g a n e s e o x i d e s in t h e J i x i a n S y s t e m w i t h an age o f a b o u t 1 5 0 0 - - 1 4 0 0 Ma, G a o b a n h e lead-zinc ore, Wafangzi m a n g a n e s e ore (c. 1 0 0 0 Ma), c o p p e r ore in the S h i c a o h e F m . and uvanite in the Taizi F o r m a t i o n o f the S h e n n o n g j i a G r o u p . T h e r e is l e a d - - z i n c ore, p y r i t e , coal etc. in the G a o y u z h u a n g F m . in the Y a n s h a n R a n g e a n d the organic c a r b o n c o n t e n t in the Taizi, Wunshihe and S o n g z i y u a n F m s . is as high as 0 . 4 3 - 6.16%. The average c o n t e n t o f a m i n o acid in t h e s e f o r m a t i o n s is 5 . 8 9 - 13.47 X 10 -3 ~ m g-i (Qin Z h e n g y o n g et al., 1984). T h e figures f r o m t h e Jixian section are 4 0 - - 5 0 X 10 -3 /~m g-1 ( C h e n G u a n g z h o n g et al., 1981}. All o f t h e s e d a t a suggest b i o c h e m i c a l i n f l u e n c e o n s e d i m e n t a t i o n . S u l p h u r i s o t o p e s in m a r i n e s u l p h a t e are c o m m o n l y c o n s i d e r e d to be unif o r m on a w o r l d - w i d e basis f o r a given p e r i o d o f geological t i m e . T h e evolution o f s u l p h u r i s o t o p e s has b e e n said to reflect global t e c t o n i c p r o c e s s e s ( L a m b e r t et al., 1983). T h e r e is clear e v i d e n c e o f i s o t o p i c f r a c t i o n a t i o n in the S h e n n o n g j i a G r o u p . T h e values o b t a i n e d f r o m the S h e n n o n g j i a G r o u p can be c o m p a r e d w i t h biological s u l p h u r , m o d e r n sea w a t e r s u l p h u r and s u l p h u r f r o m e v a p o r i t e s {Fig. 5). T h e 534S values f r o m the D a y a n p i n g F o r m a t i o n { > 1 6 0 0 Ma), as i n d i c a t e d b y Qin Z h e n g y o n g ( 1 9 8 4 ) is + 1 5 . 6 2 -1 9 . 8 7 o / o o . This value is similar to t h a t o f m o d e m m a r i n e sulphur. T h e G a o y u z h u a n g F m . ( 1 5 0 0 - - 1 6 0 0 Ma) has 534S values m a i n l y in the range o f - 1 3 - - +24 o / o o . T h e 534S values f r o m t h e Taizi F o r m a t i o n range f r o m
F"T"~ s
I ;','',',~,'; ~ " " y ~, ~ ." ~,.~.>~\'~.,"" . :TY/..
;
~
":14
i /- / 2 I i~ / . . ".',.~ . . . . . .".~. " / - ' . ' , "×,~/~1
111
1712 A
D E +40
-30
~20
~10
-10
20
30
-40
Fig. 5. The relative compositions of ~3~S in Precambrian strata of China and 5~S of known materials in nature. A=83"S of various materials in nature (adapted from Holser et al., 1966); I=Meteorite sulphur; II=Sulphur of modern sea-water; III=Biological sulphur; IV=Evaporite sulphate; B=8~4S in Precambrian strata, China; l=Wutai Group (+1.2 -+2.4% 0) (adapted from Li Shushan, 1980); 2=Dayanping Fro. of Shennongjia Group (.15.62 - +19.87% 0); 3=Taizi Fro. of Shennongjia Group (-0.26 -- +24.11% o); 4= Gaoyuzhuang Fm. of Jixian System (-13 -- +24"/o0) (adapted from Huang Xueguang, 1982); 5=Shicaohe Fm. {+18.91 -- *27.93%0 ) of Shennongjia Group.
86
:I o----___o2
,o
~
"
~ . . . . '~........
""
5
~B
=~"~,
............. B~8~B5
I
I
I
I
I
-L
I
I
I
I
I
I
La
Ce
Pr
Nd
Sm
Eu
C.kl
Tb
Dy
14o
Er
Tm
I b
I
Lu
Fig. 6. Comparison of REE patterns of the middle and upper Proterozoic in Jixian and Shennongjia regions with the average Hutuo Group of the lower Proterozoic (Qin Zhengyong et al., 1984), the average Wutai Group of the Archaean (Qin Zhengyong et al., 1984), the average Proterozoic rocks of Australia (Taylor, 1979) and the average Archaean rocks in Greenland (Taylor, 1979). 1=The mid--upper Proterozoic in Shennongjia; 2=The mid--upper Proterozoic in Jixian; 3=The Hutuo Group of the lower Proterozoic in Wutai Mountain; 4=The Proterozoic of Australia; 5=The Atchaean Wutai Group in Wutai Mountain; 6=The Archaean in Greenland. TABLE Ill R E E d a t a i n p . p . m , foz t h e s e d i m e n t a r y r o c k s o f m i d d l e a n d u p p e r P r o t e r o z o t c i n J i x i a n S e c t i o n
La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu REE Eu/Eu* Y
1
2
3
4
5
6
7
8
9
10
11"
3.48 10.8 2.19 7.92 2.00 0.38 1.76 0.28 1.46 0.24 0.56 0.09 0.47 0.06 31.7 0.67 8.37
27.9 61.1 8.90 35.2 10.1 2.42 12.9 2.10 11.2 1.96 4.98 0.71 4.10 0.55 184 0.72 49.6
12.5 23.8 3.94 12.3 2.57 0.47 2.15 0.37 2.00 0.42 1.14 0.18 0.94 0.13 62.9 0.65 14.9
31.1 61.2 9.59 34.0 8.02 1.44 6.88 1.21 6.63 1.31 3.82 0.62 3.98 0.61 170 0.64 37.6
1.06 2.04 1.00 1.38 0.53 0.07 0.12 0.06 0.09 0.08 0.08 0.01 0.05 0.02 6.54 0.72 0.55
1.82 2.20 0.92 1.38 0.45 0.06 0.10 0.05 0.12 0.04 0.09 0.02 0.04 0.01 7.29 0.69 0.88
6.68 15.1 2.40 6.08 1.26 0.23 0.84 0.18 0.76 0.14 0.38 0.06 0.35 0.05 34.5 0.70 4.02
15.0 30.2 4.69 14,8 4.66 1.01 3.77 0.59 2.73 0.49 1.24 0.19 1.12 0.16 87.9 0.78 12.2
36.8 70.3 9.63 27.4 5.05 0.88 3.17 0.60 2.45 0.51 1.41 0.24 1.34 0.20 160 0.69 12.5
13.0 27.4 9.23 12.1 2.22 0.44 1.77 0.29 1.69 0.31 0.84 0.12 0.77 0.12 65.3 0.72 8.69
14.7 26.8 3.88 9.82 1.95 0.52 1.12 0.25 0.71 0.13 0.38 0.06 0.44 0.07 60.9 1.08 3.16
1. J i n s e r y u Fro. ( J ~ a u c o a / t / c s a n d s t o n e ) 2 . Xl-m-li*~_- F r o . ( s a n d y sha}e) 3. T / e l h ~ F r o . ( d o l o m / t e ) 4. H o n ~ h u / z h u s n 8 F i n . (silty s h a h ) 5. W ~ F r o . ( e h e r t y d o l o m i t e ) 6. Y a n z h u a n j F r o . (red siltbea~ng muddy dolosto~) 7. G a o y u z h u a n l F r o . ( m a n s a n o u s d o l o l t o n e ) 8. D a h o ~ y u F r o . (silty d o l o s t o n e ) 9. T u a n s h a n z i Fro. ( d o l o m i t l c s a n d s t o n e ) 1 0 . C " h u a n l i n g g o u Fro. (silty d o l o m i t e ) 11. Ch~Igzhousou Fro. (co~lomesate) * T h e Eravels i n t h i s c o n g l o m e r a t e s h o u l d b e t h e p r o d u c t o f a t e r r ~ e n o u s p r o v i n c e i n A r e h a u n ,
1.06 2.19 0.88 1.28 0.44 0.065 0.14 0.034 0.11 0.03 0.08 0.017 0.065 0.016 6.56 0.65 1.29
3.72 4.57 0.57 2.47 0.49 0.12 0.40 0.17 0.40 0.089 0.23 0.034 0.20 0.30 13,49 0.86 3.98
2
12.70 34.90 3.48 11.50 2.47 0.55 2.23 0.37 2.21 0.44 1,21 0.18 1.02 0.14 73.40 0.71 12.8
3 7.25 15.50 2.06 7.04 1.43 0.28 1.05 0.17 0.98 0.20 0.51 0.068 0.50 0.07 37.61 0.67 5.32
4 27.2 55.6 7.94 31.26 6.95 1.59 6.72 1.10 5.94 1.14 3.07 0.48 2.79 0.37 1.5209 0.7 28.8
5 4.5 6.14 1.07 4.21 0.97 0.21 0.81 0.19 0.79 0.17 0.41 0.066 0.32 0.043 19.90 0.7 6,56
6 12.30 22.9 3.38 13.3 2.77 0.60 2.38 0.41 1.93 0.38 1.03 0.14 0.84 0.12 62.48 0.7 14.20
7 41.90 84.8 10.6 34.5 6.49 1.52 4.43 0.77 3.56 0.68 1.82 0.29 1.64 0.23 193.23 0.82 7.10
8
A
3.58 38 5.44 80 0.78 8.9 3.18 32 0.66 5.6 0.15 1.1 0.56 4.7 0.11 0.77 0.59 4.4 0.12 1.0 0.29 2.9 0.025 0.41 0.23 2.8 0.027 0.4 15.74 183 0.75 0.64 5.34 27
9 19 38 4.3 16 3.7 1.1 3.6 0.66 8.7 0.82 2.3 0.32 2.2 0.3 97 1.0 22
B 9.5 17 2.0 8.0 2.8 1.1 3.1 0.58 3.4 0.73 2.0 0.28 1.9 0.25 54 1.1 20
C
1. Macaoyuan Fm. (dolostone with stromatolites) 2. Waganxi Fm. (stromatolitic reef dolostone) 3. Songziyuan Fm. (magnetite) 4. Shicaohe Fm. (red mud-bearing dolomite) 5. Wenshuihe Fro. (silty shale) 6. Taizi Fm. (dolomitic limestone) 7. Kuangshishan Fm. (silty dolomite) 8. Luanshigou Fm. (purplish-red siltstone) 9. Dayanping Fro. (silty dolostone) A.B.C.=Compositk)n of the post-Archaean continental crust (Taylor, 1979) (A. Upper crust B. Total crust C. Lower crust).
La Ce Pr Nd Sm Eu Gd Tb Dy Hu Er Tm Yb Lu REE Eu/Eu* Y
1
REE data in p.p.m, for the sedimentary rocks of the middle and upper Proterozoic in the Shennongjia Section
TABLE IV
Oo
12a
lla
9a
8a I_
6a
~
4a
3a
5a
....
la
E I~
~h
'-
Age
1950
1600
Orogeny
Fe203 red b e d
K.P
Mn.B.Pb Sr.stone coal K
Qin~ong uplifting
Volcanic activity
red b e d Ba g y p s u m
Fe.Mn
Fe
B
Luanxlan uplifting
ot~oleny
wuuae
Jixlan uplifting
A
1400
1200
I000
900
(Ma)
biological sulphur 5~'S - 1 3 to +24°/00
C
Lower
21
31
48
42
44
50
51
High
D
~ ~
E
i
~
llb
10b
9b
8b
7b
5b
4b
3b
2b
lb
12b >177o u (Ma)
~,
Q0
,~
~
g,
~!
Stratigraphic units
Orogeny
Volcanic activity
Volcanic activity
weathezlng crust
ancient
Gen]lng orogeny
A
red b e d
stone coal FezO 3
U.V
red b e d
Ba.Cu
Fe
B
to +19
°/oo
Sea w a t e r sulphur 5~S +15 t o +19
- 0 . 2 to +24°/00
biological sulphur 63'S
°/oo
+18
5~S
sulphur
Evaporation
C
ShennongJia region (miogeosyncline type)
2.'/ Lower
5.9
13.5
h/gh
D
E
A.Crtagal m o v e m e n t . B . T y p o c h e m i c a l e l e m e n t s , ore f o r m i n g e l e m e n t s a n d s e d i m e n t a r y f o r m a U o n . C . S u l p h u r i s o t o p e (°/o0). D . C o n t e n t of a m i n o acid (in 10 -~ # m / g ) . E . C h a r a c t e r l s t i c s of R E E . l a . J / n g e r y u Fro. 2 a . X l a m a l l n g Fro. 3a.Tiellng Fro. 4 a . H o n p h u l z u a n g F m . 5 a . W u m i s h a n Fro. 6 a . Y a n g z h u a n g F m . 7a. G a o y u z h u a n g Fro. 8 a . D a h o n g y u Fro. 9 a . T u a n s h a n z i Fro. 1 0 a . C h u a n l / n g g o u Fro. 1 1 a . C h a n g z h o u g o u Fm. 1 2 a . B a d a o h e and Q i a n x i Groups. l b . M a c a o y u a n Fro. 2b.Waganxi Fro. 3 b . S o n g z l y u a n Fro. 4 b ~ h l c a o h e Fro. 5 b . W e n s h u l h e Fro. 6 b . Y e m a h e Fro. 7 b . T a i z i Fro. 8 b . K u a n g s h i s h a n Fro. 9 b . D a w o k e n g Fro. 10b. L u a n s h / g o u Fro. 1 1 b . D a y a n p / n g Fm. 1 2 b . K o n g l / n g G r o u p .
,
Stratigraphic
y a n A h a n re8ton ( p l a t f o r m t y p e )
C h e m o s t r a t i g r a p h i c c o r r e l a t i o n of the m i d d l e a n d u p p e r P r o t e r o z o i c b e t w e e n Y a n s h a n a n d S h e n n o n g J l a s e d i m e n t a r y basins
TABLE V
00 0o
89
-0.26 -- +24 o/oo, similar to biological sulphur. The 53+S values from the Shicaohe Formation (c. 1400--1500 Ma) are all positive values (+18.91 +27.93 o/oo), similar to evaporitic sulphur. Compared with known natural evaporites with 63+S values ranging from +9 to +32 o/oo, this is a somewhat narrow spread, because the 834S values from evaporites of different geological periods differ somewhat. Generally the k n o w n range is from I o/oo to 4 o/oo. The 534S values from the Archaean Wutai Group of China (Li Shuxun, 1981) are +1.2 to +2.4 o/oo, close to the values of meteoritic sulphur. The preliminary data from the Precambrian of China suggest a progressive increase in 53"S values with decreasing age. Taylor and McLennan (1981a, b) and McLennan (1982) used REE pat~ terns to study the Archaean--Proterozoic boundary. We have also summarized REE data from the Chinese Precambrian (Tables III and IV). REE show a progressive increase in abundance from the Wutai Group and Hutuo Groups of the Archaean to the middle and upper Proterozoic. REE are more a b u n d a n t in clastic and clay-rich rocks than in carbonates. The REE in clastic and clay-rich rocks of the Proterozoic in Shennongjia and Jixian is close to upper crustal abundances (Taylor, 1979). The REE patterns, normalized to chondrites (Taylor et al., 1981c), in the Proterozoic of China including the Hutuo Gp. Changcheng System, Jixian System, Qingbaikou System and Sinian System (Fig. 6) show a rather steep curve with a distinct Eu anomaly. The Eu/Eu* ratio is 0.67--0.70. The Z REE is higher, about 40--60 ppm. The Z L R E E / Z H R E E ratio is about 8. These REE patterns are similar to those in post-Archaean sedimentary rocks of Australia. In contrast, the REE patterns of the Archaean Wutai Group differ from those of the Proterozoic. The patterns are gently inclined with no Eu anomaly.
100
SO
Z
c 9 20 \
TO
°L •
c~
~
Nd
i
I
Sm
E.
k
~
J
gb
~
L
~
,
L
Er
Tm
&
~
Lu
Fig. 7. R E E patterns from rocks of the Sinian System in the Shennongjia region, i= Nantuo Fro. (conglomeratic argillite);2= Dengying Frn. (siltshale).
90 T h e E u / E u * ratio is close to 1. T h e Z R E E is a b o u t 76 p p m and the ratio o f Z L R E E / Z H R E E is 9--11. T h e p a t t e r n s are similar to t h o s e o f the Arc h a e a n o f West Greenland. T h e R E E p a t t e r n s o f the Sinian S y s t e m show s t e e p l y inclined V-shaped curves (Fig. 7). T h e negative Eu a n o m a l y is very distinct and t h e E u / E u * ratio is b e t w e e n 0.59 and 0.65. These results are c o m p a r a b l e to R E E p a t t e r n s f r o m s e d i m e n t a r y r o c k s o f the A r c h a e a n in G r e e n l a n d and S o u t h Australia, the P r o t e r o z o i c in Australia a n d the H u r o n i a n S u p e r g r o u p o f C a n a d a ( M c L e n n a n et al., 1979). All o f t h e d a t a discussed a b o v e are s u m m a r i z e d in Table V. ACKNOWLEDGEMENTS
The a u t h o r s are greatly i n d e b t e d t o Prof. C h e n J i n b i a o and o t h e r colleagues w h o gave us help in these c h e m o s t r a t i g r a p h i c investigations. REFERENCES Chen Jinbiao, Zhang Huimin, Zhu Shixing and Zhao Zhen, 1980. Research on Sinian Suberathem of Jixisn, Tianjin. In: Research on Precarnbrian Geology -- the Sinian Suberathern in China. Tianjin Science and Technology Press, Tainjin, pp. 56--114 (in Chinese). Chen Haoshou, 1983. Lead and sulfur isotope studies of the stratabound polgmetallic deposits in China. Bull. Chin. Acad. Geol. Sci.,Miner. Dep., 2:79--87 (in Chinese). Holser, W.T. and Kaplan, I.R., 1966. Isotope geochemistry of sedimentary sulfates. Chem. Geol., 1: 93-135. Kishicia, A. and Ricco, L., 1980. Chernogeratigraphy of lava sequences from the Rio Itapicurn Greenstone Bashi State Brazil. Precambrian Res., 11: 161--178. Lambert, I.B. and Donnelly, T.H., 1983. Implications of Precambrian sulfur isotope compositions. In: International symposium on late Precarnbrian geology, Tainjin, Organizing committee for the I.S.L.P. and Chinese Acad. Geol. Sci., pp. 75--76. Leinen, M., Heath, G.R. and Muratli, C., 1980. Chemical stratigraphy and paleoenvironrnent of Cenozoic north Pacific sediments. EOS, Am. Geophys. Union, Trans., 61: 257. McLennan, S.M., 1982. On the geochemical evolution of sedimentary rocks. Chem. Geol., 37: 335--350. McLennan, S.M., Fryer, B.J. and Young, G.M., 1979. The geochemistry of the carbonaterich Espanola Formation (Huronian) with emphasis on the rare earth elements. Can. J. Earth Sci., 16: 230--239. McLennan, S,M., Fryer, B.J. and Young, G.M., 1979. Rare earth elements in Huronian (Lower Proterozoic) sedimentary rocks: composition and evolution of the postKenoran upper crust. Geochim. Cosrnochirn. Acta, 43: 375--388. Nanee, W.B. and Taylor, S.R., 1976. Rare earth patterns and crust evolution I: Australia post-Archean sedimentary rocks. Geochirn. Cosrnochim. Acta, 40: 1539--1551. Qin Zhengyong, 1980. A preliminary study on geochemistry of the Sinian Suberathern in the Yanahan range, North China. In: Scientific Papers on Geology, Beijing, pp. 75--84 (in Chinese). Qin Zhengyong, Cheng Meiqi, Yang Xiuen and Du Tangzhi, 1984. The model of chernostratigraphy in Proterozoic China. In: Scientific Papers on Geology, Beijing, pp. 179--194 (in Chinese). Sversensky, D.A., Ryre, D.M. and Doe, B.R., 1979. The lead and sulfur isotopic compositions of galena from a Mimisippi valley-type deposit in the new lead belt, southeast Missouri. Econ. Geol., 74: 149--253.
91 Taylor, S.R., 1979. Chemical composition and evolution of the continental crust: the rare earth element evidence. In: M.W. McElhinny (Editor), The Earth: Its Origin, Structure and Evolution, Academic Press, London, pp. 353--376. Taylor, S.R. and McLennan, S.M., 1981a. The rare earth element evidence in Precambrian sedimentary rocks: implications for crustal evolution. Precambrian Plate Tectonics, pp. 530--536. Taylor, S.R. and McLennan, S.M., 1981b. The composition and evolution of the continental crust: rare earth element evidence from sedimentary rocks. Philos. Trans. R. Soc. London, Ser.A: 301: 381--391. Taylor, S.R. and McLennan, S.M., 1981c. Rare earth element evidence for the chemical composition of the Archaean crust. Geol. Soc. Aust. Spec. Publ., 7 : 255--261. Turner, P., 1980. Continental red beds. Develop. Sedimentaol., 29 : 1--66. Wang Yuelun, Lu Zongbin, Xing Yusheng, Gao Zhenjia, Lin Weixing, Ma Guogan, Zhang Luyi and Lu Songnian, 1980. Subdivision and correlation of the Upper Precambrian in China. In: Research on Precambrian Geology -- the Sinian Suberathem in China. Tianjin Science and Technology Press, Tianjin, pp. 1--30 (in Chinese). Yamamoto, S., Honjo, S. and Merriam, D., 1978. Quantitative chemical stratigraphy of the Nio Brara Chalk (Cretaceous) in western Kansas. Comput. Geol., 3 : 2 3 5 244. Zhang Huimin and Zhang Wenzhi, 1984. Middle and Upper Proterozoic magnetostratigraphy and tectonic evolution in Eastern China. In: Scientific Papers on Geology. Beijing, pp. 150--161 (in Chinese). Zhang Wenzhi and Li Pu, 1980. Palaeomagnetism of the Sinian Suberathem in the Jixian, China. Bull. Chin. Acad. Geol. Sci., Set. 4, 1 : 1 1 1 - - 1 2 2 (in Chinese). Zhao Zigiang, Xing Yusheng, Ma Guogan, Yu Wen and Wang Ziqiang, 1980. The Sinian System of eastern Yangtze, Hubei. In: Research on Precambrian Geology - the Sinian Suberathem in China. Tianjin Science and Technology Press. Tianjin, pp. 31--35 (in Chinese).