Vol . 18 No. 3 　　　　　　CHIN ES E J OURNAL O F GEOCHEMIS TR Y 　　　　　　1999

Characteristic Elemental Compositions of the Yangtze River and Yello w River Surface Sediments and Their Geological Background 3 YAN G S HOU YE ( 杨守业) AND L I CON GXIAN ( 李从先) ( L aboratory of M ari ne Geology , S tate Educational Depart ment , Tongji U niversity , S hanghai 200092 , Chi na)

Abstract : Significant differences are noticed in major and trace element compositions between t he Yangtze River and t he Yellow River surface sediments. The former sediments are rich in some major elements such as K , Fe , Mg , Al , and most of t he trace elements which show wide variations in element concentrations , whereas t he Yellow River sediments only have higher Ca , Na , Sr , Ba , Th , Ga , Zr , Hf contents and show slight variations in element contents. In t he Yangtze River Basin are widely distributed intermediate2acid igneous rocks and complicated source rocks toget her wit h strong chemical weat hering which determine t he elemental compositions of t he Yangtze River sediments , while t he elemental compositions of t he Yellow River sediments are decided by t he chemical composition of loess from t he Loess Plateau and intense p hysical weat hering. Cu , Zn , Sc , Ti , Fe , V , Ni , Cr , Co , Li and Be can be used to distinguish t he Yangtze River sediments from t he Yellow River sediments and be treated as tracers for bot h t he sediments to study t he processes of t heir mixing and diffusion in t he coastal zones of China. Key words : Yangtze River ; Yellow River ; surface sediment ; elemental composition ; tracer

Introduction Rivers are t he bridges linking lands and oceans (or seas) . The total amount of sediment discharged by global rivers to t he oceans is estimated at 135 ×108 tons annually , of which 70 % is derived f rom Sout h Asia and large islands around t he Pacific and Indian oceans ( Milliman et al. , 1983) . The Yangtze and Yellow rivers are two famous ones in t he world wit h a drainage area of 1. 8 ×106 km2 and 0. 75 ×106 km2 , a total annual amount of suspended matter of 5 ×108 tons and 11 ×108 tons , and a total annual amount of water discharge of 9200 ×108 m3 and 420 ×108 m3 , respectively. The huge seaward t ransport has a great influence on shallow2sea sedimentation in China ( Qin Yunshan et al. , 1989 ) . Element geochemical st udies of t he Yangtze and Yellow river surface sediment s are of great significance in revealing t he composition of shallow2sea sediment s in China , and t he processes of mixing and diff usion of t he Yangtze and Yellow river sediment s in t he coastal zones along t he Yellow Sea and East China Sea. Moreover , t his st udy will cont ribute to determining t he time t he Yangtze and Yellow rivers first poured into t he seas as well2developed rivers , exploit river mout h resources and investigate river mout h pollution. Recently t he element geochemist ry of t he Yangtze and Yellow river sediment s has been well documented (Li Yuanhui et al. , 1984 ; Huang Weiweng et al. , 1985 , 1992 , 1994 ; Li ISSN 100029426 3 This research project was financially supported jointly by t he National Natural Science Foundation of China (No . 49676288) and Lab. of Marine Geology , Tongji University.

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Peiquan et al. , 1991 ; Zhao Yiyang et al. , 1992 ; Zhao Yiyang , 1983 ; Qiu Cuihui et al. , 1984 ; Han Jiancheng , 1996 ; Zhou Yongqing , 1987 ; Chen Jingsheng et al. , 1986 ) . On t he basis of t he differences in elemental composition between t he Yangtze and Yellow river sediment s , t his paper will f urt her discuss t he influence of source rock composition and weat hering of drainage basins on t he chemical composition of fluvial deposit s , and determine t he t racing element s of t he Yangtze and Yellow river sediment s. Materials and Methods Samples were taken f rom t he lower reaches and river mout h areas of t he Yangtze and Yellow rivers ( Fig. 1) . The Yangtze River sediment samples were collected f rom 18 different localities , including Nanjing , Zhenjiang , Nantong , Wusong , Chongming , Changxing , Sanjiagang , Laogang , t he Caoyang Farm and Gaodong ( Nos. C12C18) , and t he Yellow River sediment samples f rom 13 localities , including Jinan , Dongying , Diaokou and t he river mout h area of t he Yellow River ( Nos. H12H13 ) . The samples were taken in a flood plain far f rom river port s to avoid pollution. In t he laboratory all t he samples were separated to get bulk samples of t he same grain size ( < 63 μm ) wit h t he subsiding met hod and dried below 60 ℃. During t hesample processing all utensils were cleaned wit h acid and highly pure water , and metal staining such as iron was Fig. 1. The area studied and sample localities. avoided. Element concent rations were determined by ICP2A ES at t he State Key Laboratory of Ore2forming Mechanism of Nanjing U niversity. In order to supervise t he accuracy and precision , standard samples and duplicate samples were analyzed , and t he result s indicate t hat t he relative deviations for most of t he element s are less t han 5 % , except Mo and Pb whose deviations are more t han 5 %. This shows t he whole analytical procedure was reliable. Elemental Compositions of the Yangtze River and Yellow River Sediments Presented in Table 1 are t he average concent rations of 41 element s in t he Yangtze River and Yellow River sediment s , toget her wit h standard deviations ( STD) , coefficient s of variation ( CV ) and relative deviations ( RD) for t he two kinds of sediment . M ajor elements

As is shown in Table 1 , t he Yangtze River sediment s are rich in K , Fe , Mg and Al , © 1995-2003 Tsinghua Tongfang Optical Disc Co., Ltd. All rights reserved.

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especially Fe and Mg whose relative deviations exceed 40 % , indicating t heir content s are much higher in t he Yangtze River sediment s t han in t he Yellow River sediment s. In cont rast , t he Yellow River sediment s are rich in Na and Ca. Apart f rom Na , t he coefficient s of variation of element s in t he Yangtze River sediment s are higher t han t hose of t he Yellow River sediment s , reflecting highly variable data for sediment s samples f rom t he Yangtze River. Table 1. Comparison of element concentrations bet ween the Yangtze River and the Yellow River sediments K Na Ca Fe Mg Al Mo Zn Pb Co Ni Ba Mn Cr Th Ga V Nb Be Cu Sr Li Sc Ti Zr Hf La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Y

CJ

HH

RD %

STDhh

STDcj

CVhh

CVcj

2. 20 1. 47 3. 06 5. 49 2. 91 11. 64 4. 22 116. 2 50. 49 15. 14 40. 93 461. 2 828. 9 77. 95 16. 92 19. 91 140. 5 19. 28 2. 23 47. 56 135. 5 51. 44 11. 23 6775 258. 3 6. 37 36. 64 66. 13 8. 70 33. 87 6. 18 1. 31 5. 72 0. 87 4. 85 1. 00 2. 64 0. 39 2. 30 0. 35 24. 98

1. 95 2. 25 3. 88 3. 35 1. 84 9. 86 3. 38 60. 33 29. 49 10. 98 26. 71 663. 2 433. 6 64. 77 18. 51 20. 33 108. 9 15. 58 1. 57 17. 80 186. 6 30. 34 8. 49 3890 262. 5 6. 93 29. 23 54. 50 7. 15 26. 93 5. 05 1. 05 4. 69 0. 85 3. 95 0. 84 2. 24 0. 35 2. 06 0. 32 20. 75

12. 0 - 41. 9 - 23. 6 48. 4 45. 1 16. 6 22. 1 63. 3 52. 5 31. 9 42. 0 - 35. 9 62. 6 18. 5 - 9. 0 - 2. 1 25. 3 21. 2 34. 7 91. 1 - 31. 7 51. 6 17. 8 54. 1 - 1. 6 - 8. 4 22. 5 19. 3 19. 6 22. 8 20. 1 22. 0 19. 8 14. 8 20. 5 17. 4 16. 4 10. 8 11. 0 9. 0 18. 5

0. 2 0. 4 0. 2 0. 2 0. 1 0. 4 1. 4 4. 6 2. 3 1. 6 2. 1 114. 1 22. 6 10. 8 5. 1 2. 7 14. 8 1. 8 0. 1 2. 0 12. 9 5. 8 0. 4 283. 5 66. 2 1. 1 2. 6 5. 1 0. 7 2. 7 0. 5 0. 1 0. 4 0. 1 0. 4 0. 1 0. 3 0. 1 0. 4 0. 1 1. 7

0. 2 0. 2 0. 3 0. 9 0. 5 1. 4 1. 6 22. 0 10. 4 2. 3 6. 2 156. 7 180. 8 15. 4 3. 3 3. 3 28. 1 4. 5 0. 3 14. 7 11. 8 9. 2 1. 4 1505 86. 9 1. 7 4. 2 7. 5 1. 0 4. 0 0. 7 0. 2 0. 7 0. 1 0. 6 0. 1 0. 3 0. 1 0. 3 0. 1 3. 3

7. 7 17. 4 4. 0 5. 7 7. 0 4. 1 43. 2 7. 6 7. 6 14. 8 7. 8 17. 0 5. 2 16. 5 27. 9 13. 1 13. 6 11. 6 7. 4 11. 5 7. 0 19. 3 4. 9 7. 3 25. 3 15. 5 9. 0 9. 4 10. 1 10. 1 9. 6 8. 5 8. 6 7. 7 10. 1 11. 0 13. 8 14. 6 18. 9 20. 2 13. 1

10. 1 14. 4 8. 5 17. 1 19. 2 12. 5 33. 1 19. 4 20. 5 15. 4 15. 6 31. 9 23. 2 19. 1 19. 4 16. 4 20. 0 23. 8 13. 8 32. 3 8. 9 18. 6 13. 0 23. 5 38. 9 31. 0 11. 8 11. 8 12. 4 12. 5 11. 5 11. 8 11. 9 10. 2 12. 0 11. 6 12. 6 12. 9 13. 2 15. 7 14. 0

Note : CJ or cj —Yangtze River sediments ; HH or hh —Yellow River sediments. Unit : μg/ g ; K , Na , Ca , Fe , Mg and Al in oxide wt %.

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No. 3 　　　　　　　　CHIN ES E J OURNAL O F GEOCHEMIS TR Y 　　　　　　　　 261 T race elements

Analyses of 20 t race element s show t he Yangtze River sediment s have higher values t han t he Yellow River sediment s , wit h t he exception of Ba , Th , Ga , Sr , Zr and Hf . Zn , Pb , Co , Ni , Mn , Be , Cu , Li and Ti are particularly abundant in t he Yangtze River sediment s wit h t he RDs > 30 %. Comparatively , t he Yellow River sediment s are characterized by high Sr and Ba content s. The STDs and CVs of most t race element s in t he Yangtze River sediment s are higher t han t hose in t he Yellow River sediment s , also indicating highly variable data for t he Yangtze River samples and relatively concent rated data for t he Yellow River samples. R are2eart h elements ( R EEs )

Fifteen rare2eart h element s and t heir STDs and CVs in t he Yangtze River sediment s are higher t han in t he Yellow River sediment s. Moreover , variations in CVs among different samples and different rare2eart h element s are less t han t hose among major and t race element s , reflecting t he REEs are similar in property and mechanism of enrichment in t he sediment s. Based on t he above analyses , it is held t hat t he elemental compositions of t he Yangtze River sediment s are obviously different f rom t hose in t he Yellow River sediment s , each of t hem having it s own characteristic elemental compositions. Cluster analysis is quite usef ul to distinguish t he Yangtze River sediment s f rom t he Yangtze River sediment s , and t he analytical result s revealed t hat t he Yangtze River and Yellow River sediment s could be distinctively classified as two clusters ( Fig. 2) . Discussion It is generally known t hat t he main factors cont rolling sediment compositions include source rock , chemical and p hysical weat hering under t he influence of climate and tectonic activity , hydraulic sort , relief of sedimentary basin , sedimentary environment , p hysical and chemical characters of sedimentary medium , diagenesis and metamorp hism ( Nechaev , V . P. et al. , 1993 ) . Because diagenesis and Fig. 2. Q2mode cluster plot of t he Yangtze River and Yellow metamorp hism in t he Yangtze River River sediment samples. and Yellow River sediment s are negligible and sorting effect is also small owing to t he same grain size of analytical samples , t he compositions of t he Yangtze River and Yellow River sediment s are principally cont rolled by source rock and weat hering extent . S ou rce rock

It is generally accepted t hat 90 % of t he Yellow River sediment s was derived f rom t he Loess Plateau along t he middle reaches of t he Yellow River ( Ren Meier et al. , 1986) , and t he drainage basin is abundant in evaporate , which has resulted in t he high content s of Ca , Na and © 1995-2003 Tsinghua Tongfang Optical Disc Co., Ltd. All rights reserved.

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K. Discriminant f unction ( DF ) is applied to describing t he similarity extent in chemical composition between t he Yangtze River and/ or Yellow River sediment s and t he loess. DF = ( C1X/ C2X) / ( C1L / C2L ) - 1 where C1X/ C2X is t he concent ration ratio of two element s in t he Yangtze River sediment s or t he Yellow sediment s , and C1L / C2L t he concent ration ratio of t he two element s in t he loess. Elemental ratios are taken wit h an attempt to reduce t he influence of sediment grain size on element concent rations. The ratio of an element to Al is most usually used because Al is stable during sedimentation and is most concent rated in clay. The lower t he DF is (i. e. , near zero) , t he closer t he chemical composition of sediment to t hat of loess. Table 2 present s t he calculated Table 2. Comparison of element concentration ratios bet ween the Yangtze River sediments , Yellow River sediments and loessic deposits Ca/ Al Fe/ Al Mg/ Al Zn/ Al Pb/ Al Ni/ Al Cr/ Al V/ Al Nb/ Al Be/ Al Cu/ Al Sr/ Al Li/ Al Ti/ Al La/ Al Ce/ Al Sm/ Al Eu/ Al L u/ Al Y/ Al K/ Na K/ Ca Al/ Na Fe/ Mg Al/ (Al + K + Na + Ca)

CJ 0. 26 0. 47 0. 25 9. 98 4. 34 3. 52 6. 7 12. 07 1. 66 0. 19 4. 09 11. 64 4. 42 582. 0 3. 15 5. 68 0. 53 0. 11 0. 03 2. 15 1. 54 0. 72 8. 16 1. 89 63. 17

HH 0. 39 0. 34 0. 19 6. 12 2. 99 2. 71 6. 57 11. 05 1. 58 0. 16 1. 81 18. 92 3. 08 395 2. 96 5. 53 0. 51 0. 11 0. 03 2. 1 0. 9 0. 5 5. 34 1. 82 55. 01

Loess 0. 66 0. 11 0. 2 5. 5 2. 33 2. 85 5. 41 6. 68 0. 87 0. 17 1. 79 19. 53 2. 72 303. 0 2. 7 5. 47 0. 47 0. 09 0. 04 2. 1 1. 26 0. 29 6. 67 1. 71 50. 12

DFcj 0. 60 3. 45 0. 26 0. 82 0. 86 0. 24 0. 24 0. 81 0. 90 0. 14 1. 28 0. 40 0. 63 0. 92 0. 16 0. 04 0. 12 0. 19 0. 15 0. 02 0. 22 1. 48 0. 22 0. 11 0. 26

DFhh 0. 40 2. 20 0. 06 0. 11 0. 28 0. 05 0. 21 0. 66 0. 81 0. 05 0. 01 0. 03 0. 13 0. 30 0. 10 0. 01 0. 08 0. 13 0. 08 0. 00 0. 29 0. 72 0. 20 0. 06 0. 10

　　　Note : The Chinese loess data are from Wu Mingqing and Wen Qizhong (1995) .

result s , indicating t hat t he DF of most of t he element s in t he Yellow River sediment s are less t han 0. 5 and also lower t han t he DF of t he Yangtze River sediment s. This shows t hat t he concent ration ratios of most of t he element s to Al in t he Yellow River sediment s are close to t hose of t he loess as compared wit h t hose of t he Yangtze River sediment s , such as Ca/ Al , Mg/ Al , Zn/ Al , Pb/ Al , Ni/ Al , Be/ Al , Cr/ Al , V/ Al , Sr/ Al , Ti/ Al , LA/ Al and L u/ Al. Thus t he elemental compositions of t he Yellow River sediment s have virt ually inherited t hose of t he loess. Ot her element ratios such as K/ Ca , Al/ ( Al + K + Na + Ca ) and Fe/ Mg in t he Yellow River sediment s are also close to t hose of t he loess as compared wit h t he Yangtze River sediment s. Therefore , t he higher Ca , Sr content s and lower t race element concent rations in t he Yellow River sediment s could be explained in terms of t he chemical compositions of loess and evaporate in t he Yellow River drainage basin. Zr and Hf are closely coexisting element s , and © 1995-2003 Tsinghua Tongfang Optical Disc Co., Ltd. All rights reserved.

No. 3 　　　　　　　　CHIN ES E J OURNAL O F GEOCHEMIS TR Y 　　　　　　　　 263

t he main zirconium2containing minerals are zircon and some rare2eart h minerals. Nearly all haf nium is contained in t he zirconium2containing minerals. Because it is very stable during sedimentation , and often enriched in sands , zircon has a high content in sand , silt and fine sand. High Zr and Hf content s in t he Yellow River sediment s might be related to t he high content of zircon in t he sediment s which contain a lot of silt . The absence of multi2metal2high background zones formed as a result of tectonic and magmatic activities in t he Yellow River drainage basin might also lead to t he lower content s of various t race metals in t he Yellow River sediment s. The Yangtze River drainage basin is principally located on t he Yangtze platform , which is characterized by complex st ruct ure and extensive drainage area ( more t han twice t hat of t he Yellow River drainage basin ) , resulting in a comprehensive source of t he Yangtze River sediment s , so it is very difficult to work out t he average composition of t he st rata in t he whole drainage basin and hence it is impossible to use a couple of rocks to represent t he source rock of t he Yangtze River sediment s ( Qiu Cuihui et al. , 1984) . Igneous rocks in t he Yangtze River drainage basin are more developed t han t hose in t he Yellow River drainage basin , especially in it s middle2upper and lower reaches where intermediate2acid rocks are widespread and associated wit h various metallic ore prospect s ( Chen Jingsheng et al. , 1986 ) . The Yenshanian metallogenetic stage is a main metallogenetic epoch in t he eastern part of China , where metallic ores associated wit h acid rocks , include t hose of Mo , Be , Cu , Pb , Zn , Nb and REE ; correspondingly , iron and copper ores are associated wit h intermediate and intermediate2basic rocks. Thus , most t race element s in t he st rata of t he Yangtze River drainage basin have higher background values t han t hose of t he Yellow River drainage basin , which mainly include siderop hile element s such as Fe , Mn , Ti , V , Cr , Co and Ni , and chalcop hile element s such as Cu , Pb and Zn. This may explain why t he Yangtze River sediment s have higher element concent rations t han t hose in t he Yellow River sediment s. Li and Nb are two typical lit hop hile element s and also have higher content s in t he intermediate2acid rocks ; Sc , a dispersed lit hop hile element , is contained mainly in dark mafic minerals and enriched in basic rocks. Therefore , t hese element s also have higher content s in t he sediment s of t he Yangtze River drainage basin where various igneous rocks are widespread. Characteristics of variation of element concent rations in t he sediment s also provide information about t heir provenance. Element concent rations vary greatly in t he Yangtze River sediment samples and are higher t han t hose in t he Yellow River sediment samples , showing a comprehensive source of t he Yangtze River sediment s and a relatively simple provenance of t he Yellow River sediment s. W eat heri n g

Al/ ( Al + K + Na + Ca ) , K/ Na , K/ Ca , Al/ Na and Fe/ Mg ratios in t he sediment s are often used as indices to reflect t he intensity of chemical weat hering , and t hese ratios are high during st rong chemical weat hering and low during weak chemical weat hering ( Sawyer , 1986) . The reason is t hat Na and Ca are most mobile and easy to t ransport and leach during chemical weat hering ; Mg is also mobile during st rong chemical weat hering ; K , Al and Fe are largely preserved in t he clay formed by chemical weat hering. These indices for t he Yangtze River sediment s are markedly higher t han t hose for t he Yellow River sediment s , indicating st ronger chemical weat hering in t he Yangtze River drainage basin t han in t he Yellow River drainage basin. Climate in t he Loess Plateau area is often cold and dry wit h scarce vegetation and low rainfall , resulting in loose soil and st rong p hysical weat hering. The Loess Plateau is an area where t he erosion rate is highest in China , and t he ratio of p hysical erosion rate to chemical © 1995-2003 Tsinghua Tongfang Optical Disc Co., Ltd. All rights reserved.

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CHIN ES E J OURNAL O F GEOCHEMIS TR Y 　　　　　　　Vol . 18

erosion rate is about 75 ( Chen Jingsheng et al. , 1984 ) . Such a high ratio demonst rates t hat t he Yellow River possesses a high sand load and a high sedimentation rate. Therefore , most of t he element s are of little variation and have basically inherited t he chemical composition of t he loess. Evaporate and carbonate weat hering were dominated in t he Yellow River drainage basin , and because of intense p hysical weat hering , alkali and alkali2eart h metals have been less leached , resulting in high Ca , Sr , Na content s in t he Yellow River sediment s. In cont rast , t he Yangtze River drainage basin is characterized by a warm and humid climate wit h abundant vegetation and rainfall , where silicate and carbonate weat hering is dominant and chemical weat hering is much st ronger t han p hysical weat hering wit h a ratio of p hysical erosion rate to chemical erosion rate of 2 - 5 ( Chen Jingsheng et al. , 1984 ) . St rong chemical weat hering in t he Yangtze River drainage basin brings about st rong leaching and dissolution. As a consequence , lot s of soluble salt s have been leached , resulting in t he low content s of alkali and alkali2eart h element s in t he Yangtze River sediment s , while less mobile element s , including Sc , Ti , Al , Fe , Th and Cr , have been principally preserved i n2sit u . A pplication of characteristic elements as t racers

Based on t he above analyses , it is evident t hat almost all t he element s show obvious variations in concent ration between t he Yangtze River and Yellow River sediment s. Considering t he extent of variation in element concent ration and t he stability of element s in hypergenically geochemical environment s , we select t he t ransition metals including Sc , Ti , V , Cr , Ni , Co , Fe , Cu , Zn , Be and Li as t he t racing element s to distinguish t he Yangtze River sediment s f rom t he Yellow River sediment s. Alt hough significant differences are noticed in concent rations of Pb , Th , Mo , Ba , Na , Ca , Sr , Ba and Mn between t he Yangtze River sediment s and t he Yellow River sediment s , t hey are readily influenced by some factors such as human2activity2induced pollution , ocean source materials and mobilization in t he hypergene environment. So t hese element s are not appropriate to be used as t racing element s. Establishment of t racing element s of t he Yangtze River and Yellow River sediment s is of great significance in t he st udy of supplying , mixing and diff usion of t he Yangtze River and Yellow River materials in t he coastal zones and shallow continental shelves of China. On t he ot her hand , it also provides a new met hod for determining t he time t he Yangtze River or t he Yellow River first poured into t he sea as a well2developed river. Conclusions 1. Element concent rations in t he Yangtze River sediment s are evidently different f rom t hose in t he Yellow River sediment s , i. e. , t he former sediment s are rich in K , Fe , Mg , Al and most t race element s , especially t he first t ransition metals such as Sc , Ti , V , Cr , Mn , Co , Ni , Cu and Zn while t he latter sediment s only have higher Ca , Na , Sr , Ba , Th , Ga , Zr , Hf content s t han t he former sediment s , of which Ca , Sr and Ba are much higher. 2. Complicated geological background of t he Yangtze River drainage basin differs f rom t he loess2dominant provenance of t he Yellow River. This would cause larger variations in element concent rations in t he Yangtze River sediment s t han in t he Yellow River sediment s. 3. Widely dist ributed igneous rocks and st rong chemical weat hering in t he Yangtze River drainage basin are responsible for t he lower content s of alkali and alkali2eart h element s and t he higher content s of t race element s. In cont rast , high Ca , Na , Sr , Ba content s in t he Yellow River sediment s are dependent on t he compositions of t he loess and evaporate widely developed © 1995-2003 Tsinghua Tongfang Optical Disc Co., Ltd. All rights reserved.

No. 3 　　　　　　　　CHIN ES E J OURNAL O F GEOCHEMIS TR Y 　　　　　　　　 265

in t he middle reaches of t he Yellow River and intense p hysical weat hering in t he river drainage basin. 4. Some element s such as Sc , Ti , V , Cr , Fe , Co , Ni. Cu , Zn , Be and Li show significant differences in concent rations between t he Yangtze River and t he Yellow River sediment s and are stable in t he hypergene environment . Therefore , t hese element s can be used as t racers to distinguish t he Yangtze River materials f rom t he Yellow River materials , t hus providing a new met hod for investigating t he supply , mixing and diff usion of bot h river materials in t he coastal zones and continental shelves of China , as well as in t he West Pacific Ocean. References Chen Jingsheng , Li Yuanhui , and Le Giaxiang , 1984 , Physical and chemical erosions of major rivers in China : Science Bulletin , v. 15 , p . 932 - 936. Chen Jingsheng , Zheng Chunguang , Gao Guangsheng , and Chen Chenqi , 1986 , Basic characteristics of environmental geochemistry of suspended matter and bed clay in major rivers in t he eastern part of China : Scientia Geograp hica Sinica , v. 6 , n. 4 , p . 325 - 331 (in Chinese) . Han Jiancheng , 1996 , Study of major elements in t he Yangtze estuarine sediments and related form quantitative analysis : Acta Oceanogica Sinica , v. 18 , n. 4 , p . 49 - 55 (in Chinese) . Huang Weiweng and Zhang Jing , 1994 , Characteristics of chemical matter transportation from t he Yangtze River to East China Sea : Acta Oceanogica Sinica , v. 16 , n. 2 , p . 53 - 62 (in Chinese) . Huang Weiweng , Zhang Jing , and Liu Minguang , 1985 , Speciation of heavy metals in t he Yellow River estuarine sediments : J . of Shandong College of Oceanology , v. 15 , n. 1 , p . 137 - 145 (in Chinese) . Huang Weiweng , Zhang Jing , and Zhou Zhenghao , 1992 , Particulate element inventory of t he Yellow River : A large , high turbidity river : Geochim. Cosmochim. Acta , v. 56 , p . 3669 - 3680. Li Peiquan and Zhang Shuzi , 1991 , INA analysis and geochemical study of 39 elements in surface sediments in t he lower reaches and river mout h of t he Yellow River : Acta Oceanogica Sinica , v. 13 , n. 4 , p . 507 - 518 ; v. 13 , n. 5 , p . 649 - 655 (in Chinese) . Li Yuanhui , H. Teraoka , and Yang Zuoshen , 1984 , The elemental composition of suspended particles from t he Yellow and Yangtze rivers : Geochim. Cosmochim. Acta , v. 48 , p . 1561 - 1564. Milliman , J . D. , and R. H. Meade , 1983 , World2wide delivery of river sediment to t he ocean : J . of Geol. , v. 91 , p . 1 - 21. Nechaev , V. P. and W. C. Isp hording , 1993 , Heavy mineral assemblages of continental margins as indicators of plate2tectonic environments : J . of Sedi. Petrology , v. 63 , n. 6 , p . 1110 - 1117. Qin Yunshan , Zhao Yiyang , Chen Lirong , eds. , 1989 , The Geology of t he Yellow Sea : Beijing , Ocean Press , p . 1 - 289 (in Chinese) . Qiu Cuihui , Zheng Jianxun , Yang Shaojing , Qian Qingfang , and Yang Yinan , 1984 , Studies of chemical compositions and influencing factors of suspended matter at controlling stations in t he lower reaches of t he Yangtze River , t he Yellow River and t he Zhujiang River : Science Bulletin , v. 17 , p . 1063 - 1066. Ren Meier and Si Yuanliang , 1986 , Sand transport of t he Yellow River and its influence on t he sedimentation in t he Bohai Gulf and t he Yellow Sea : Scientia Geograp hica Sinica , v. 6 , n. 1 (in Chinese) . Sawyer , E. W. , 1986 , The influence of source rock type , sorting on t he geochemical weat hering of clastic sediments from t he Quatico matasedimentary belt , Superior Province , Canada : Chemical Geol. , v. 55 , p . 77 - 95. Wu Mingqing and Wen Qizhong , 1995 , Average chemical compositions of t he Chinese loess : A typical representative of UC : Rock Facies and Paleogeograp hy , v. 15 , n. 2 , p . 127 - 136. Zhao Yiyang , 1983 , Some geochemical patterns of shelf sediments of t he China Seas : Scientia Geologica Sinica , v. 4 , p . 307 - 314 (in Chinese) . Zhao Yiyang and Yan Mingcai , 1992 , Comparison of element abundances in sediments in t he Yellow River , t he Yangtze River and t he China seas : Science Bulletin , v. 37 , p . 1202 - 1204. Zhou Yongqing , 1987 , Distributions of elements in t he sediments at t he mout h of t he Yellow River and its relation wit h t he environment : Marine Geology and Quaternary Geology , v. 7 , p . 123 - 129 (in Chinese) .

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