Geochemical Implication of Rare Earth Elements in ...

JOURNAL O F RAR E EARTHS 　　　　　　　　　　　　　　　　　　　　　　　　2001 　Vol . 19 　No . 1

Geochemical Implication of ΞRare Earth Elements in Process of Soil Development HUAN G Cheng2min ( 黄成敏) 1 , GON G Zi2tong ( 龚子同) 2 ( 1 . College of Environmental Science and Engineering , Sichuan University , Chengdu 610065 , China ; 2 . Institute of Soil Science , Chinese Academy of Sciences , N anjing 210008 , China ) Abstract : The geochemical characteristics and behavior of rare earth elements ( REE) in soils developed on the basalts in the northern part of Hainan Island erupted in different time were studied as well as the REE partition in the soil2formation process and its implication on soil development degree . The results show that the total REE con2 tent in soils is correlative with soil age significantly and can be selected as the index to show soil evolution. With the soil developing intensively , light rare earth elements (LREE) gain and heavy rare earth elements ( HREE ) lose . The trends of positive Ce2anomaly and negative Eu2anomaly are remarkable with soil development . Key words : rare earths ; soil ; geochemistry ; basalt ; partition CL C number : S151 ; O613. 33 　　Document code : A 　　Article ID : 1002 - 0721 ( 2001) 01 - 0057 - 06

　　With similar chemical properties , rare earth elements are always paragenetic in natu2 ral environment . However , REE may be frac2 tionated in various geochemical conditions ow2 ing to the minute discrepancy among atomic structures and chemical properties of REE. Furthermore , distribution status , occurrence patterns of REE turn into geochemical indices with special implication [ 1 ,2 ] . Seeking REE geochemical behavior is the key to studying rock2forming and mineralization as well as the earth formation and evolution [ 3 ] . Extensive researches on REE migration , loss and accumulation in process of rock weathering have been conducted [ 4～6 ] . Soil formation is closely relative to but different from rock weathering. The reports are rare on REE geo2 chemistry in process of soil formation. A large area of basalts covers on the northern Hainan Island , southern China , erupted in different periods since Cainozic Era . The soils derived from basalts which have different soil ages , constitute a chrono2sequence of soils varying in soil development sharply. REE geochemical behavior in process of soil formation and devel2

opment can be discussed by studying on the soil chrono2sequence in the northern Hainan Island , and the environment of soil formation and formation mechanism of secondary miner2 als of REE can be infered.

1 　Materials and Methods 1. 1 　Materials Soils , developed on basalts erupted in different periods since Quaternary Era , were sampled. Sample sites and basic properties of soils are listed in Table 1. The precipitation varies drastically in different regions of the is2 land resulting from towering mountains in mid2 dle part of the island. Profile HE11 , collected in Sanmenpo , Qiongshan , lies in hilly platforms and coastal plains in the eastern island , where the annual mean temperature ranges from 2410 to 2415 ℃, and ≥10 ℃ accumulation tempera2 ture from 8400 to 8600 ℃, and annual mean precipitation between 1800 and 2000 mm [ 7 ] . Other five profiles belong to semi2humid region of coastal platform in the northern island ,

Ξ Received date : 2000 - 06 - 12 ; revised date : 2000 - 08 - 22

Foundation item : Project supported by the National Natural Science Foundation of China (49831004) Biogra phy : HUANG Cheng2min (1968 - ) , Male , Doctor , Associate professor

© 1994-2006 China Academic Journal Electronic Publishing House. All rights reserved.

http://www.cnki.net

　　　　　　　　　　　　　　　　　　 JOURNAL O F RAR E EARTHS 　　　　　　　　　　　　　　　　　　　Vol . 19 58

( Table 1) .

where the annual mean temperature ranges from 2310 to 2410 ℃, and ≥10 ℃accumula2 tion temperature from 8 ,500 to 8 ,700 ℃, and annual mean precipitation between 1 ,400 and 1 ,800 mm. Under similar conditions of soil formation and with the same parent materials , the higher soil acidity and the lower silica2alumina molec2 ular ratio and silica2sesquioxide molecular ratio of soil clays are , the deeper soil development is [ 8 ] . The values of p H , silica2alumina molec2 ular ratio and silica2sesquioxide molecular ratio of clays of sampled soils illustrate that the soil development degree accords with soil ages

1. 2 　REE Measurement Samples were dissolved with alkali fu2 sion and measured by State Key Laboratory of Mineral Deposit Research , Nanjing Univer2 sity , with J Y 38S single2channel scanning plasma spectrometer manufactured by J ION YVON Company in France . The detection limit of the instrument : 011 ～ 10 μg ・kg - 1 , RSD ≤ 2 %. The test condition : 1 m of focal length , 01005 nm of resolution , 013 L ・m - 1 of flow rate of carried gas , 013 MPa of carried gas pressure . [9 ]

Ta ble 1 　Basic properties of sa mples Sample No .

Sample sites (Profile No . )

Horizons

Soil depth/ cm

Soil ages/ 10 4a

pH

SiO 2/ Al 2O3 (Clay)

SiO2/ (Al 2O 3 + Fe 2O3) (Clay)

HE39

Shizilu ,

Solum

0～15

< 1. 0 [10 ]

6. 38

—

—

HE40

Qiongshan

Solum

15～30

6. 57

2. 28

1. 56

HE41

( HE09)

C horizon

30～50

7. 13

2. 29

1. 65

HE42

C horizon

50～80

6. 89

—

—

HE430

Bed rock

80 +

—

—

—

HW111

Yangpu ,

Solum

0～12

6. 17

2. 16

1. 50

HW112

Danzhou

Solum

12～44

6. 13

2. 06

1. 47

HW113

( HW03)

C horizon

44～100

6. 45

—

— 4. 01

9. 0

[10 ]

—

5. 99

4. 75

—

—

6～22

4. 72

2. 00

1. 46

Solum

22～37

5. 25

2. 05

1. 47

HW118

Solum

37～65

5. 10

2. 11

1. 53

HW119

C horizon

65～100

5. 61

2. 11

1. 53

HW120

Saprolite

100 +

—

—

—

HW114

Bed rock

100 +

HW115

Deyiling ,

Solum

0～6

HW116

Danzhou

Solum

HW117

( HW04)

64 [11 ]

HE43

Yunlong ,

Solum

0～25

4. 49

—

—

HE44

Qiongshan

Solum

25～50

5. 27

1. 34

0. 96

HE45

( HE10)

Solum

50～70

5. 23

1. 43

1. 03

HE46

Solum

70～90

5. 11

1. 45

1. 04

HE47

Solum

90～120

4. 79

1. 40

1. 01

HE48

Solum

120～140

4. 77

—

—

4. 31

—

—

133

[10 ]

HE49

Sanmenpo ,

Solum

0～12

HE50

Qiongshan

Solum

12～30

4. 32

1. 32

0. 94

HE51

( HE11)

Solum

30～80

5. 01

1. 29

0. 94

Solum

80～120

4. 94

1. 26

0. 92

HE52

148

[10 ]

HW106

Xinying ,

Solum

0～25

4. 17

—

—

HW107

Danzhou

Solum

25～52

4. 85

1. 35

1. 00

HW108

( HW02)

Solum

52～88

4. 82

1. 40

1. 04

HW109

Solum

88～128

4. 64

1. 27

0. 93

HW110

Solum

128～150

4. 73

1. 27

0. 94

181

[10 ]


http://www.cnki.net

No . 1 　　　　　　　　　　　　Geochemical Implication of R EE in Process of Soil Development 　　　　　　　　　　　　　 59

2 　Results and Discussion 2. 1 　REE contents Contradictory results have been proposed about REE migration and fractionation in pro2 cess of rock weathering. Price et al . [ 6 ] sug2 gested that REE changed during early rock weathering. However , Middelburg et al . [ 12 ] supposed that REE migration or fractionation occurred during late rock weathering. Our re2 sults show that the older soil ages are , the higher the total REE contents are when soils developed in the same conditions. Tables 2 and 3 demonstrate that total REE contents in all of soil layers exceeded those in rocks except sample HW112. Total REE contents reached 306184 to 332107 mg ・kg - 1 in profile HW02 in contrast with 70 mg・ kg - 1 in profile HW03. With further development of the soil , the dif2 ference in REE content between soils and rock widened owing to relative enrichment of REE with weak shifting capability while macro2ele2

ments as Ca , Mg , K and Na except Fe , Al were leached strongly [ 13 ] . Total REE is correl2 ative with soil ages significantly , and the cor2 relative coefficient reaches 019937. Conse2 quently , total REE could serve as an excellent index to estimate soil development degree . REE in profile HE11 were leached more inten2 sively resulting in total REE decreasing , though soil of profile HE11 is older than other soils of HW03 , HE05 , HE09 and HE10. In2 side soils , REE contents in surface layer are u2 niversally lower than those in the other layers. Under strong acidic conditions , the ad2 sorption capacity of clay minerals reduces , and base elements and REE were leached in parent materials while REE illuviated in lower layers. As a result , REE in surface layer low2 ers [ 14 ,15 ] . REE contents in saprolites always exceed those in rocks and are lower than in overlaying soils. Nesbitt drew a conclusion that the con2 tents of the heavy rare earth elements increased

Ta ble 2 　REE contents ( mg・kg - 1) in soil horizons of prof iles and rock 3 Samples

La

Ce

Pr

Nd

Sm

Eu

Gd

Tb

HE39

13. 55

36. 51

3. 998

14. 72

3. 599

1. 236

3. 870

0. 5478 3. 406

0. 6615 1. 539

0. 2389 1. 421

0. 2245 13. 50

HE40

14. 77

42. 38

4. 546

16. 61

4. 173

1. 496

4. 456

0. 6353 3. 880

0. 7352 1. 708

0. 2584 1. 501

0. 2179 13. 65

HE42

15. 04

37. 38

4. 281

15. 53

4. 027

1. 538

4. 782

0. 6549 4. 007

0. 7738 1. 818

0. 2623 1. 518

0. 2308 16. 84

HE430

14. 03

25. 54

4. 369

15. 92

3. 977

1. 576

5. 175

0. 6945 4. 210

0. 8443 1. 890

0. 2873 1. 517

0. 2374 19. 59

HW111

14. 11

39. 66

4. 275

15. 59

4. 079

1. 544

4. 708

0. 6741 4. 057

0. 8164 1. 892

0. 3004 1. 679

0. 2558 18. 14

HW112

15. 41

32. 5

4. 766

17. 4

4. 556

1. 725

5. 491

0. 7723 4. 618

0. 9193 2. 158

0. 3288 1. 843

0. 2742 21. 85

HW113

9. 18

40. 6

3. 165

11. 38

3. 171

1. 27

3. 93

0. 5204 3. 294

0. 6398 1. 491

0. 2337 1. 309

0. 1923 13. 18

HW114

17. 09

33. 74

4. 604

16. 79

4. 073

1. 583

4. 528

0. 5512 3. 182

0. 5858 1. 188

0. 1742 0. 8519 0. 1293 13. 06

HW115

22. 32

81. 25

5. 118

19. 21

4. 445

1. 527

4. 855

0. 6275 3. 654

0. 7106 1. 585

0. 243

0. 20

14. 77

HW117

27. 51

95. 36

6. 784

26. 18

5. 823

2. 022

6. 287

0. 8277 4. 726

0. 9076 2. 077

0. 3254 1. 71

0. 261

19. 62

HW119

24. 20

128. 60 5. 74

21. 14

5. 039

1. 743

5. 58

0. 7008 3. 912

0. 7659 1. 69

0. 2673 1. 438

0. 2132 15. 11

HW120

38. 31

105. 3

6. 952

25. 14

5. 404

1. 844

5. 837

0. 7738 4. 309

0. 8722 1. 955

0. 3141 1. 660

0. 263

HE43

31. 74

66. 64

9. 51

35. 5

8. 923

2. 978

9. 226

1. 378

7. 736

1. 461

3. 653

0. 5191 3. 153

0. 4464 31. 77

HE45

34. 18

91. 23

9. 74

34. 82

9. 03

3. 047

9. 555

1. 311

7. 326

1. 443

3. 438

0. 5443 3. 182

0. 4951 29. 32

HE47

20. 58

81. 10

5. 956

19. 62

5. 754

1. 872

5. 873

0. 7965 4. 555

0. 9096 2. 153

0. 3786 2. 195

0. 3444 17. 70

HE49

13. 36

46. 21

2. 114

6. 186

1. 587

0. 4012 1. 7300 0. 2442 1. 599

0. 3905 0. 9783 0. 2096 1. 171

0. 1989 8. 25

HE52

12. 15

63. 16

2. 099

7. 329

1. 438

0. 3718 1. 548

0. 2243 1. 552

0. 3696 0. 9598 0. 1871 1. 145

0. 1934 8. 21

HW106

42. 74

100. 11 1. 05

43. 3

9. 304

3. 094

9. 274

1. 247

6. 641

1. 246

2. 819

0. 4199 2. 422

0. 3579 25. 16

HW108

52. 09

123. 2

13. 48

50. 55

12. 3

4. 073

12. 05

1. 627

8. 716

1. 626

3. 678

0. 5502 3. 163

0. 4734 33. 76

HW110

48. 94

124. 5

11. 97

45. 38

10. 18

3. 391

10. 35

1. 457

7. 799

1. 494

3. 404

0. 5021 2. 739

0. 4088 34. 33

3

12. 75

27. 20

HNQT

14. 575 4. 0525 1. 555

Dy

Ho

Er

0. 705

Tm

Yb

1. 334

1. 545

Lu

0. 190

3 Average REE contents of Quartz2tholeiite (QT) in Hainan Island [16 ]


http://www.cnki.net

Y

18. 01


Ta ble 3 　 Total REE and ratios of L REE/ HREE 3 ΣLREE/ΣHREE

ΣREE/ (mg・kg - 1) Samples 1

2

3

1

2

HE39

99. 02

256. 24

71. 81

2. 90

2. 43

HE40

111. 02

289. 75

81. 78

3. 11

2. 49

HE42

108. 68

284. 01

75. 92

2. 52

2. 28

HE430

99. 86

273. 01

63. 49

1. 90

1. 97

HW111

111. 78

288. 18

77. 59

2. 44

2. 18

HW112

114. 61

307. 23

74. 48

2. 00

2. 00

HW113

93. 56

230. 15

67. 62

2. 77

2. 20

HW114

102. 13

271. 31

74. 81

3. 21

3. 10

HW115

161. 85

370. 97

130. 91

4. 78

3. 59

HW117

200. 42

468. 65

159. 69

4. 54

3. 45

HW119

216. 12

457. 92

183. 07

6. 29

4. 15

HW120

216. 94

505. 09

178. 69

5. 38

4. 08

HE43

214. 63

579. 69

150. 76

2. 62

2. 38

HE45

238. 66

619. 97

177. 30

3. 22

2. 62

HE47

169. 79

412. 69

132. 26

3. 86

2. 77

HE49

84. 63

186. 67

69. 36

4. 73

3. 14

HE52

100. 93

201. 72

86. 01

6. 02

3. 75

HW106

259. 17

663. 47

202. 56

4. 23

3. 45

HW108

321. 34

828. 64

247. 48

3. 90

3. 25

HW110

306. 84

757. 28

237. 00

3. 91

3. 37

HNQT

-

-

62. 57

-

-

do [ 17 ] . Yang et al . [ 18 ] reported that no obvious partition for REE occurred in red soils in the southern China compared with bed rocks. Nev2 ertheless , Fig. 1 demonstrates that the slopes of REE patterns improve gradually , i . e . , LREE enrich relatively in soils derived from basalts in Hainan Island with soil ages and de2 velopment degree increasing. Song et al . [ 19 ] and Braun et al . [ 13 ] drew the same conclusions in dealing with granite and syenite weathering crusts. The REE patterns in slightly developed soils are similar to those in bed rocks , and LREE and HREE fractionated in strongly de2 veloped soils evidently ( Fig. 1) .

3 1 : Oringinal total REE contents ; 2 : Chondrite2nomalized REE con2 tents ; 3 : Total REE contents except Pr , Gd , Dy , Ho , Er , Tm

in comparison with bed2rock at early and mid2 dle stages , and reduced at the stage of ex2 tremely weathering of rock after his study on weathering crust of granodiorite [ 4 ] . But the ra2 tios of LREE/ HREE in profiles HW03 and HE09 show that REE fractionated faintly in be2 ginning stage of soil genesis , and LREE/ HREE in solum is lower than that in bed rock , the results are not identical to Liu et al . [ 1 ] and Braun et al . [ 13 ] . In general , LREE/ HREE in strongly developing soils are higher than those in weakly developing soils , however , the lin2 ear equation between LREE/ HREE and soil ages does not exist .

2. 2 　REE distribution patterns in soils Chondrite2nomalized N La/ Yb and N La/ Eu are unable to indicate REE partition in process of soil formation due to negative Eu2anomaly , but Chondrite2nomalized REE patterns can

The chemistry of groundwater is an impor2 tant factor to control REE mobilization. By an2 alyzing groundwater of profiles HW03 and HW04 , groundwater with the composition HCO3- 2K + 2Na + . HCO3- might form very solu2 ble complexes with HREE , and led HREE sol2 ubility to much higher than LREE solubility , therefore LREE accumulated when HREE lost in weathering product [ 20 ] . HREE enriched in groundwater unlike in soils , especially in groundwater of profile HW04 ( Fig. 2) . The p H influences REE behavior greatly , p H reduction favors the dissolution and mobilization , while p H increment leads to the deposition of REE. As the p H value ( 7117 ) of groundwater for profile HW04 was lower than that ( 7150 ) of profile HW03 , the REE migration in the for2 mer is much higher than that in the latter . REE geochemical features in groundwater con2 firm that HREE were leached markedly and


http://www.cnki.net

No . 1 　　　　　　　　　　　　Geochemical Implication of R EE in Process of Soil Development 　　　　　　　　　　　　　 61

4 ) . Eu/ Eu 3 is higher than 1 in basalt and lowers in 6 soil profiles , of which Eu/ Eu 3 is negative in solum of profile HE11. Reduction of Eu/ Eu 3 occurred in granitic weathering crusts , too [ 5 ] , as a result of Eu2 + and Sr 2 + leaching and losing after Eu3 + being reduced to Eu2 + [ 22 ] . In a word , positive Ce2anomaly and negative Eu2anomaly are remarkable with soil development . La/ Ce , La/ Nd and Ce/ Nd are significant to indicate the degree of rock weathering [ 23 ] and the weathering environment [ 1 ] . But these ratios change chaotically in Table 4 , which demonstrates that La/ Ce , La/ Nd and Ce/ Nd are not suitable to indicate soil formation and development. Also , a lot of studies on REE fractionation in process of soil formation under strong biotic action should be conducted.

LREE were accumulated comparably in soils as soil developed toward climax.

Fig. 2 　 Chondrite2nomalized REE patterns groundwater —●—HW04 ; —○—HW03

in

2. 3 　Special ratios of REE in soils It was reported that Ce and Eu appeared anomalous in certain layers of the weathering crusts [ 5 ,21 ] . Table 4 indicates that Ce/ Ce 3 of bed rocks is negative and of soils is always positive. Braun et al . [ 13 ] and Yang et al . [ 18 ] found there is the positive Ce2anomaly with dif2 ferent degrees likewise in red soils in the southern China , and explained the phe2 nomenon resulted from change of the conditions of oxidation. However , the Ce and Eu anomaly is not evident in horizons inside soils ( Table

3 　Conclusion REE distribution and partition in soils predominantly depend on features of REE2en2 riched minerals in bed rock and pedogenic en2

Ta ble 4 　Geochemical special ratios of REE 3 Samples

Ce/ Ce 3

Eu/ Eu 3

N La/ Yb

N La/ Eu

La/ Nd

Ce/ Nd

La/ Ce

HE39

1. 194

1. 013

6. 429

2. 599

0. 921

2. 480

0. 371

HE40

1. 245

1. 061

6. 634

2. 341

0. 889

2. 551

0. 349

HE42

1. 121

1. 072

6. 680

2. 319

0. 968

2. 407

0. 402

HE430

0. 785

1. 062

6. 235

2. 111

0. 881

1. 604

0. 549

HW111

1. 229

1. 077

5. 666

2. 167

0. 905

2. 544

0. 356

HW112

0. 913

1. 055

5. 637

2. 118

0. 886

1. 868

0. 474

HW113

1. 813

1. 100

4. 728

1. 714

0. 807

3. 568

0. 226

HW114

0. 915

1. 127

13. 525

2. 560

1. 018

2. 010

0. 507

HW115

1. 830

1. 005

11. 280

3. 466

1. 162

4. 230

0. 275

HW117

1. 680

1. 022

10. 846

3. 226

1. 051

3. 642

0. 288

HW119

2. 626

1. 007

11. 346

3. 292

1. 145

6. 083

0. 188

HW120

1. 553

1. 004

15. 559

4. 926

1. 524

4. 189

0. 364

HE43

0. 923

1. 004

6. 787

2. 527

0. 894

1. 877

0. 476

HE45

1. 203

1. 003

7. 242

2. 660

0. 982

2. 620

0. 375

HE47

1. 763

0. 985

6. 321

2. 607

1. 049

4. 134

0. 254

HE49

2. 093

0. 740

7. 692

7. 895

2. 159

7. 470

0. 289

HE52

3. 010

0. 762

7. 154

7. 748

1. 658

8. 618

0. 192

HW106

1. 109

1. 019

11. 897

3. 275

0. 987

2. 312

0. 427

HW108

1. 119

1. 023

11. 103

3. 032

1. 030

2. 437

0. 423

HW110

1. 238

1. 010

12. 046

3. 422

1. 078

2. 743

0. 393

5. 564

1. 944

0. 875

1. 866

0. 469

HNQT 3

3 Ce/ Ce = N Ce/ ( N La・N Pr)

1/ 2

3

; Eu/ Eu = N Eu/ ( N Sm・N Gd)

1/ 2

; N La/ Yb and N La/ Eu are chondrite2nomalized


http://www.cnki.net


vironment , e . g. , climate , biota and pedo2 genic time , etc . In soils of a chrono2sequence with similar pedogenic environment expect time , the deeper soil development degree is , the higher total REE content in soils is as soil ages increase . Total REE content in soils is correlative with soil age significantly , which could be applied to evaluate soil degree . With the soil developing intensively , LREE gains and HREE loses. The trends of positive Ce2 anomaly and negative Eu2anomaly are remark2 able with soil development . Moreover , La/ Ce , La/ Nd and Ce/ Nd as well as N La/ Yb and N La/ Eu for estimating rock weathering are un2 suitable to indicate soil development . References : [1 ] 　L IU Y J , CHAO L M , L I Z L , et al . 　Element Geo2 chemistry ( in Chin. ) [ M ] . Beijing : Science Press , 1984. [ 2 ] 　WEN Q Z , DIAO G Y , YU S H , et al . 　Geochemistry of Loess in China ( in Chin. ) [ M ] . Beijing : Science Press , 1989. [3 ] 　ZHAO Z H. 　Principles of Microelement Geochemistry (in Chin. ) [M ] . Beijing : Science Press , 1997. [4 ] 　NESBITT H W. 　Mobility and fractionation of rare earth elements during weathering of a granodiorite [J ] . Nature , 1979 , 279 : 206 - 210. [5 ] 　CONDIE K C , DENGATE J , CULL ERS R L . 　Behav2 ior of rare earth elements in a paleoweathering profile on granodiorite in the Front Range , Colorado , USA [J ] . Geochim. Cosmochim. Acta . , 1995 , 59 : 279 - 294. [ 6 ] 　PRICE R C , GRAY C M , WILSON R E , et al . 　The effect of weathering on rare2earth element , Y and Ba abundances in Tertiary basalts from southeastern Aus2 tralia [J ] . Chem. Geol . , 1991 , 93 : 245 - 265. [7 ] 　Division of soil and fertilizer , Agricultural Branch of Hainan Province ( Editor ) . The Soils in Hainan ( in Chin. ) [ M ] . Haikou : Tri2circle Press and Hainan Press , 1994. [8 ] 　BIRKELAND P W. 　Pedology , Weathering , and Geo2 morphological Research [ M ] . New York : Oxford Uni2 versity Press , Inc . , 1974. [ 9 ] 　ROBINSON P , HIGGINS N C , J ENNER G A. 　Deter2 mination of rare2earth elements , yttrium and scandium in rocks by an ion exchange2X2ray fluorescence technique [J ] . Chem. Geol . , 1986 , 55 : 121 - 130. [ 10 ] 　GE T M , CHEN W J , XU X , et al . 　The geomagnetic

polarity time scale of quaternary for Leichiong Region — The K2Ar dating palaemagnetic evidences from igneous rocks [J ] . Acta Geophysica Sinica ( in Chin. ) , 1989 , 32 ( 5) : 550 - 558. [ 11 ] 　 FENG G R. 　Basic characteristics of basalts during Cainozic Era and its constitution environment in the coastal southern China ( in Chin. ) [J ] . Journal of the San Yat2Sen University ( Natural Sciences ) , 1992 , 27 : 93 - 103. [ 12 ] 　MIDDELBURG J J , VAN DER WEIJDEN C H , WOIT2 TIEZ J R W. 　Chemical processes affecting the mobility of major , minor and trace elements during weathering of granitic rocks [J ] . Chem. Geol . , 1988 , 68 : 253 273. [ 13 ] 　BRAUN J J , PAGEL M , HERBILON A , et al . 　Mobi2 lization and redistribution of REEs and thorium in a syenitic lateritic profile : A mass balance study [ J ] . Geochim. Cosmochim. Acta . , 1993 , 57 : 4419 - 4434. [ 14 ] 　L IU Z ( Chief Editor) . 　Microelements in Soils of China (in Chin. ) [M ] . Nanjing : Jiangsu Sci . & Tech. Press , 1996. [15 ] 　RAN Y , L IU Z. REE contents and distribution in main soils of China [J ] . Journal of the Chinese Rare Earths Society (in Chin. ) , 1994 , 12 ( 3) : 248 - 252. [ 16 ] 　 FLOWER M F J , ZHANG M , CHEN C Y , et al . Magnatism in the South China 2. Post2spreading quater2 nary basalts from Hainan Island , south China [ J ] . Chem. Geol . , 1992 , 97 : 65 - 87. [17 ] 　HUMPHRIS S E. 　The mobility of the rare earth ele2 ments in the crust [A ] . In : edited by HERDERSON P. Rare Earth Elements Geochemistry [ C ] . Amsterdam : Elsevier Science Publishers B V , 1984. 317 - 375. [18 ] 　YANG Y G , L IU C Q , YUAN K N. 　Study on REE distribution in red soils in the southern China [ J ] . Geochimica (in Chin. ) , 1999 , 28 ( 1) : 70 - 79. [19 ] 　SONG Y H , SHEN L P , WANG X J . 　Preliminary study on REE in weathering crusts of some rocks [J ] . Chinese Bulletin of Science (in Chin. ) , 1987 , 32 ( 9 ) : 695 - 698. [ 20 ] 　L I W D , WANG W B , CHEN Z F , et al . 　Laterization Geochemistry and Possibility of Lateritic Golden Ore Formation in the Southern China (in Chin. ) [M ] . Bei2 jing : Geology Press , 1995. [ 21 ] 　BRAUN J J , PAGEL M , MULL ER J P , et al . 　Cerium anomalies in lateritic profiles [ J ] . Geochim. Cos2 mochim. Acta . , 1990 , 54 : 781 - 795. [ 22 ] 　TANG S L , SUN J X , TU S D , et al . 　REE in soils of Guangzhou ( in Chin. ) [J ] . Acta Pedologica Sinica , 1980 , 17 ( 4) : 299 - 307. [23 ] 　SONG Y H , SHEN L P. 　Experimental study of REE chemistry in weathering crusts of acidified igneous rock [J ] . Geochimica (in Chin. ) , 1986 , ( 3) : 225 - 234.


http://www.cnki.net