Rare earth elements of Pacific pelagic sediments

Rare earth elements of Pacific pelagic sediments

Geochimrca PI Cormochrmica Ada Vol. 54. pp. 1093-I 103 0016.7037/90/$3.00 + .oO Copyright 0 1990PergamonPress plc. Printed in U.S.A. Rare eart...

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Geochimrca

PI Cormochrmica

Ada

Vol. 54. pp. 1093-I

103

0016.7037/90/$3.00

+ .oO

Copyright 0 1990PergamonPress plc. Printed in U.S.A.

Rare earth elements of Pacific pelagic sediments KAZUHIRO

TOYODA,’ YUJI NAKAMURA,’ and AKIMASA MASUDA~

‘Mineralogical Institute, Faculty of Science, University of Tokyo, Hongo Bunkyo-ku, Tokyo 113, Japan *Safety Analytical Unit, National Institute of Radiological Sciences, Anagawa 4-9- 1, Chiba-shi, Chiba Prefecture, 260 Japan ‘Department of Chemistry, Faculty of Science, University of Tokyo, Hongo Bunkyo-ku, Tokyo 113, Japan (Received April 5, 1989; accepted in revised form January 30, 1990)

Abstract-The chemical compositions of 140 deep-sea sediment samples collected in the Pacific were examined. The characteristic features of the abundances of REEs in the sediment samples, including pelagic red clay, calcareous ooze, and blue mud, are demonstrated especially by a variety of Ce anomalies in the shale-normalized REE pattern. Cerium abundances in blue mud samples showed little anomaly. Calcareous ooze showed a general negative Ce anomaly. The spatial distribution of the Ce anomaly in red clay appears to depend on the latitude: the red clay samples from the lower latitudes show a negative Ce anomaly, while those from the high latitudes show a positive anomaly. The positive Ce anomaly in red clay is considered to be caused by preferential scavenging of Ce from sea water to sediment. The pelagic sediments in the equatorial Pacific which show a large negative Ce anomaly have high REEs and P content and are depleted in light REEs in the shale-normalized REE pattern. The results of microscopic observation and separation by grain size indicate that a large negative Ce anomaly was incorporated with the phosphate phase in the pelagic sediment. This implies that the deep-sea sediment is rich in fish bone debris which are composed of biogenic calcium phosphate. Fish bone debris readily accumulates REE with a large negative Ce anomaly. Low sedimentation rate and high biological activity in the Central Equatorial Pacific results in a high content of fish bone debris in the sediment, which cause a large negative Ce anomaly. I. INTRODUCIION

patterns of coarser fractions exhibit a negative Ce anomaly related to biogenic components such as foraminifera and diatom, while fine fractions show a positive Ce anomaly related to submarine alternation of volcanic materials. This paper gives a detailed description of the chemical composition characteristics of deep-sea sediments having Ce anomalies. We interpreted our data from a wide variety of locations and sedimentary environments in the Pacific Ocean on the basis of earlier publications on REE marine geochemistry (e.g., by Elderfield and his co-workers). The origin of Ce anomalies in deep-sea sediments is also discussed, and the carriers of the Ce anomalies in equatorial Pacific sediments are identified using chemical analysis of samples separated by grain size.

THE CHEMISTRY OF THE rare earth elements (REEs) makes them useful in geochemical studies on sediments and sedimentary rocks (PIPER, 1974a; FLEET, 1984). The similar chemical properties and the low solubility of the REEs allow only limited elemental fractionation during weathering and diagenesis. Recently, REE enrichment in anoxic marine pore water shows that the REEs can take part in diagenetic mobilization reaction (ELDERFIELD and SHOLKOVITZ, 1987). It is reported that negative Ce anomalies in chert and deepsea sediments indicated Ce deposition in the pelagic environment (SHIMIZU and MASUDA, 1977; RANGIN et al., 198 1; MATSUMOTO et al., 1985). Hence, Ce anomalies are good indicators of sedimentary conditions in the environment. GOLDBERG (196 1) suggested that Ce is oxidized to Ce(IV) hydroxide which is more insoluble than lanthanum (III) hydroxides and is incorporated in hydroxide precipitation from sea water in an oxidized environment. The present oxidized deep-sea water always shows negative Ce anomalies (DE BAAR et al., 1985; ELDERFIELD, 1988). On the contrary, most deepsea ferromanganese nodules exhibit positive Ce anomalies. This Ce distribution reflects the effect of preferential removal of Ce(IV) from sea water. Both positive and negative Ce anomalies occur in pelagic sediments. ADDY (1979) and WHITE et al. (1985) showed that positive Ce anomalies occur in red clays from the northwest Atlantic. WANG et al. (1986) reported a negative Ce anomaly in calcareous ooze. Deep-sea sediments in the central southeast Pacific are characterized by a negative Ce anomaly (IKEDA and MASUDA, 1981; MATSUMOTO et al., 1985). TLIG and STEINBERG (1982) measured REEs in sediment size fractions from the Indian Ocean and concluded that REE

II. SAMPLING

AND ANALYTICAL

METHODS

We investigated the chemical composition of piston core samples (42 sites) from various areas of the Pacific, mainly covered by the cruises (from KH68-3 to KH84-I over the period 1968 to 1984) of the A. V. Hakuhou Muru, belonging to the Ocean Research Institute, University of Tokyo. We analyzed the chemical composition of sediment samples wellpreserved in cubic boxes which had been pushed from the top to the bottom almost successively in these piston core samples. We selected samples from depths of about 50 cm and I m for each site studied. Volcanic ash, turbidite (COLLEYet al., 1984), and metal-rich layers

(WALLACEet al., 1988) were carefully avoided. Chemical compositions of the sediment samples, sampling locations. and other information (YANG et al.. 1986; KOBAYASHIet al., 1980) are given in Appendix 1. In addition, we analyzed the surface sediments of depth O-5 cm (I 8 sites; 2 1 samples; Appendix II) collected from the Pacific during the cruise of the A. V. Hakuhou Maru by dredging. core-box sampling, and gravity sampling. Chemical compositions of deep-sea sediment samples were determined by means of ICP-OES (Inductively coupled argon plasma op1093

k. Io~oda. i! Nakamura. and A. Masuda

IO94

tlcal emission spectrometry) and INAA (Instrumental neutron acttvation analysis). The samples were dissolved in 1 M HCI fbr ICPOES measurements. For INAA, about 50 mg of each the powdered sample was irradiated together with standard rock samples for 12h at a neutron flux of I X 10” n/cm’/sec in the TRICA reactor of the Atomic Energy Institute, Rikkyo University, Japan. Gamma-ra> measurements were made twice with different cooling intervals ot 4-S and 20-30 days. ‘The variation for INAA measurements of each element observed in duplicate analyses of one of the standards was below 5% for La. Ce, Sm, and Eu: below 10% for Yb and Lu; and about IS%for Tb. Analytical errors in ICP me~urements ranged between 1-B for Ti. Al, Fe, Mn, Mg, Ca, and P, and about 10% for Na and K. Precision and accuracy of data were checked by analysis of standard rocks. and no systematic error was observed. A composite shale standard value was adopted to smooth out the natural odd-even effects of REE concentration (a modification of the Masuda-Coryell diagram; MASUDA and MATSUI, 1966). The degree of Ce anomaly can be expressed mathematically by

__ l

0.6/f

!

.

l*

.jN%* 4 l

j*.*

0.4i

l

I

/

l*

.

__

Cabl ._~

30

. . .

40 I

.

. .

.A_.

.

s

0.2

Ce/Ce* = 5Cen/f4La,. t Sm,l where n indicates shale-normalized concentrations using the shale data PIPER (1974a). We divided the bulk sample (KH70-2-9-3: 17”06W. 146” 12’W) into categories from A to F according to grain size. This sample was wet-sieved through 150 and 400 mesh into three fractions, i.e., > 105 pm, 37-105 pm, and <37 Nrn. These divided samples were rinsed with distilled water and dried. The finest grain size fraction (4~37 pm) was further separated into four fractions (A-D) of grain size < I wrn, 12 pm, 2-10 pm, and lo-37 pm, respectively, by repeated settling and decantation, according to settling velocity in water. A density of 2.6 g cm-j for grains was assumed for the computation of settling velocities of suspended sediment using Stokes’ law. Clay fractions (A and B) were collected using a centrifugal separator. III. RESULTS

AND DISCUSSION

I. Sediment t.vpe and Ce anomai~~ An estimate of the content of CaC03 in deep-sea sediments was made by assuming that the measured Ca content was present only in the form of CaC03. Calcium concentration in clay must be low (<2-3%), and Ca-feldspar is easy to dissolve away during the weathering process. The amount of apatite in the deep-sea sediment sample was also small, because P20, was found to range from O-2.5% (see Appendices). Therefore, the above a~umption is valid.

I

l

1

.

50;i l.

!

l l

40-99. Sm (Ppm)

.

l

30: I

l

20 rIs . 10

l

.

5 4 -.

.A..

l

10

.* J.,\'&

20

--30

40

-

Caai FIG. 1. The relationship between the content of samarium and calcium in pelagic sediments (all samples in Appendices).

FIG. 2. The relationship between Ce anomaly and the content of calcium in pelagic sediments (all samples in Appendices).

Figure 1 illustrates the relationship between Sm content and carbonate content in all samples from the Appendices. The REE content in pure limestones was about one-eighth of that in pure claystones. The Sm content (an intermediate REE) is chosen to represent the REEs, because the precision and accuracy of Sm data are good and Sm shows no anomalous behavior exemplified by Ce and Eu. A negative, but nonlinear, relationship between Sm content and Ca content is found (Fig. I). WANG et al. (1986) found a negative linear relationship between REEs and carbonate content in South Atlantic deep-sea sediments. The Sm content of0.9-3.5 ppm in typical calcareous ooze (assumed CaC03 > 90% implies Ca > 36% in Fig. I) is a little larger than Sm values (0.75 to 1S ppm) reported by WANG et al. (1986). However, Sm contents of 4-62 ppm in argillaceous deep-sea sediments (Fig. 1) are considerably larger than the Sm content (7.5 ppm) reported for average shale (PIPER, 1974a). Figure 2 shows the relationship between the Ce anomaly and Ca content in all sampIes from the Appendices. In the present paper all samples are divided into three categories (Fig. 2): (i) negative Ce anomalies (filled circles: Ce/Ce* < 0.9): (ii) no Ce anomaly (open triangles); and (iii) positive Ce anomalies (open circles: Ce/Ce* > 1. I ). Since precision of INAA was better than 5% for La. Ce, and Sm, analytical precision of the degree of Ce anomaly was considered to be 10%. All calcareous ooze samples (Ca > 8%) have a negative Ce anomaly (Fig. 2), which is considered to be caused by the Ce anomaly associated with the oxide coatings of foraminifera tests (PALMER, 1985). Present-day deep-sea water has a negative Ce anomaIy, resulting in a Ce-depleted REE pattern within calcareous ooze (WANG et al., 1986; LW et al., 1988). Both positive and negative Ce anomalies occur in deepsea argiliaqous sediments (Ca < 8%) in Fig. 2. The percentage of CaC03 in sediments with Ca content higher than 8% is assumed to be above 20%. REE content in calcareous ooze is one-eighth that in shales (PALMER, 1985). Accordingly, the REE content of biogenic calcite in deep-sea argillaceous sediments (Ca < 8%) is small. The biogenic opal content of deep-sea sediment can be estimated by assuming that the Si/Al ratio in terrigenous sil-

REEs in pelagic sediment icate is about 3. The percentage of biogenic opal, as calculated by the normative calculation technique (LEINEN, 1977), was below 30% in all samples (TOYODA, 1987). As the REE content of biogenic opal is negligible (SPIRN, 1965; ELDERFIELD et al., 1981), biogenic opal dilutes the REE concentration of pelagic sediments. Figure 3 shows the relationship between the degree of Ce anomaly and water depth of sampling locations in all samples from the Appendices, and reveals that the Ce anomaly in silicious deep-sea sediments (Ca < 8%) is independent ofwater depth at the sampling point. Siliceous deep-sea sediment samples, collected at depths from 4000 and 6000 m, exhibit a wide range of Ce anomalies between 0.3 and 1.5, while present-day deep-sea water has negative Ce anomalies (DE BAAR et al.. 1985; ELDERF-IELD, 1988). On the other hand, all calcareous ooze (Ca > 8%) came from a depth above 4500 m, as shown in Fig. 3. Incidentally, the calcium carbonate compensation depth (CCD) in the Pacific is at a depth of about 4200-4500 m (BERGER and WINTLERER, 1974). All the siliceous deep-sea sediment samples (Ca < 8%) were classified as either non-pelagic sediments (often called blue mud) or pelagic sediments, including red clay and siliceous ooze. We have recognized through color tone that only two samples in this study were blue mud samples (KH68-437-2 and KH70-2-18-3). These two sampling points were sited in the boundary areas of the ocean floor. The Ce anomalies in four blue mud samples are from 0.97 to 1.12, while the anomalies in red clays cover a wider range from 0.3 to 1.6.Blue muds are terrigenous deep-sea sediments in which both positive and negative Ce anomalies might be diluted by the rapid accumulation of anoxic terrigenous material which is ordinarily rich in organic matter (ROMANKEVICH, 1984). Moreover, the small Ce anomaly in blue mud might reflect the preferential release of Ce from authigenic phases in reducing sediments relative to its REE neighbors. 2. Distribution of’Ce anomaly in red clay samples Figure 4a shows the distribution of Ce anomalies of samples listed in the Appendices from the Pacific together with the

Cc/Cd 0.2

0.4

0.6

0.8

1.0 I

1.2

1.4

1095

FIG.4a. Distribution of Ce anomalies in siliceous pelagic sediments (Ca < 8 wt%) in the Pacific: filled circles indicate negative Ce anomalies; open triangles show no Ce anomalies; and open circles indicate positive Ce anomalies. Dotted areas are active spreading axes, shaded areas are upwelling zones, and arrows show currents.

previously reported values of siliceous sediments (SHIMOKAWA et al., 1972; VOLKOV and FOMINA, 1973; COURTOIS and HOFFERT, 1977; ELDERFIELD et al., 1981; MATSUMOTO et al., 1985). A negative Ce anomaly was observed near the East Pacific Rise (dotted zone in Fig. 4a) in the southeast Pacific. Although hydrothermal effluents have no Ce anomaly (MICHARD et al., 1983), hydrothermal crusts and metalliferous sediments have negative Ce anomalies, which are believed to result from hydrothermal ferromanganese oxides having a seawater-like REE pattern (PIPER, 1973; ELDERHELD and GREAVES, 198 1). Hydrothermal Fe-Mn oxides rapidly scavenge the REEs in seawater with little or no preferential scavenging of Ce(IV) (RUHLIN and OWEN, 1986; DYMOND and EKLUND, 1978), while hydrogenous ferromanganese oxides accumulate very slowly with preferential scavenging of Ce(IV) and have a positive Ce anomaly (PIPER, 1974b; THOMSON et al., 1984). As a result, there is a genetic relationship between Ce negative anomalies and submarine volcanism at spreading centers. Furthermore, a negative Ce anomaly is observed not only on and near the active spreading ridges but also in the central equatorial Pacific. Figure 4b shows the change in Ce anomalies in sediments along the 17O”W longitude. The core numbers marked with asterisks in Appendix I are the 12 sampling sites plotted in Fig. 4b. The pelagic sediments in low latitudes have negative Ce anomalies, while the ones in high latitudes have positive Ce anomalies. This dependence of Ce anomaly and REE pattein inclination on latitude in samples from 17O”W longitude was previously reported by IKEDA and MASUDA (198 1). 3. Chemical composition

FIG. 3. The relationship between the degree of Ce anomaly and water depth of the sampling location (all samples in Appendices).

The chemical composition characteristics in siliceous deepsea sediments with negative Ce anomalies, compared with sediments having no, or positive, Ce anomalies, are as follows: ( 1) high REE content (Sm > 15 ppm); (2) high content of phosphorus (P20s > 0.3%); (3) good correlation between REEs and P; (4) high content of manganese (MnO > 0.5%);

iOYh

h; Xopda,

\I‘ Nakamura. and A. Masuda

1

0

4

(5) low La/Sm ratio (La/Sm = -4) (The data plotted in Figs. 5-8 are listed in Appendix I). Good correlations are observed between REE (e.g., Sm) and P concentrations and between the Ce anomaly and P concentrations (Figs. 5 and 6). Ce anomalies decrease with increasing P concentration (i.e., 1.4-0.2). Some workers reported high REE contents and a negative Ce anomaly in fish bone debris (ARRHENIUS et al., 1957; BERNAT, 1975; ELDERFIELD and PAGETT, 1986). It is well known that fish bone debris eventually remains as microscopic crystals even in the most slowly accumulating types of oxidizing deep-sea sediment (ARRHENIUS, 1963). The biodetritus resulting from high biological activity in the euphotic zone is observed in hemipelagic and pelagic sediments underlying upwelling and in the equatorial divergence zones. High primary biological productivity tends to decrease westward away from the upwelling zone created by equatorial divergence and the loci of coastal upwelling (California and

50.

20. Sm @pm)

lo-

Y

1

L..A-u.-L

0.5 P*05(%)

.

3



*

.

‘2. .

02

FIG. 4b. The changes in the Ce anomaly along the longitude of 17O”W. Open circles are our data of sites with asterisks in Appendix I, and open squares are the data of surface sediments (50 cm- I m in depth) from Minai (1982).

01

l.p.

*.

Latitude

L.L-_LA

61

..-.

1

2

3

FIG. 5. The relationship between the contents of samarium and phosphorus in siliceous sediments (calcium contents are below 8 wt%) of all samples in Appendix I.

FIG. 6. The relationship between Ce anomaly and the content of phosphorus in siliceous sediments (calcium contents are below 8 wt%) of all samples in Appendix I.

Peru) combined with north and south equatorial currents (see Fig. 4a). This distribution of high biological productivity coincides with the negative Ce anomaly areas. The correlation between the content of Sm and P205 shown in Fig. 5 suggests that Sm content in pure apatite (about 40% P,Os) may be as high as 500-1000 ppm. This value is consistent with a high Sm concentration of fish bone in red clay reported by other workers (ARRHENIUS, 1957; BERNAT, 1975; ELDERFIELD and PAGETT, 1986). Needless to say, the REE content in other biogenic materials, including biogenic opal and biogenic calcite, is too low to explain the high REE content of deep-sea sediments having a negative Ce anomaly (SPIRN, 1965; PALMER, 1985). ELDERFIELD ( 1976) suggested that the hydrogenous component in deegsea sediments has REE concentrations several times higher than shales. Metalliferous sediment, smectite clays, and fish bone debris have relatively high REE contents (BENDER et al., 1971; PIPER, 1974a; RUHLIN and OWEN. 1986). These sources suggest that excess REEs in red clay, compared with shale, could be of hydrogenous, hydrothermal, or biogenic apatite origin. Figure 7 plots Ce anomaly against Mn content in the surface deep-sea sediment. Note that sediments with lower Mn content (MnO < 1.2%) have positive Ce anomalies, while the reverse is true for samples with higher Mn contents (MnO > 0.8%). MATSUMOTO et al. (1985) found that red clays having negative Ce anomalies in the central equatorial Pacific are associated with high Mn contents, and they considered the excess manganese to be of hydrothermal origin and the negative Ce anomalies to be the result of hydrothermal influence. Hydrothermal hydroxides rapidly scavenge the R.EEs in sea water without any preferential scavenging of Ce(IV) (RUHLIN and OWEN, 1986). However, it is possible that high Mn content in the equatorial Pacific is due to the high primary productivity of the overlying sea water. MARTIN and KNAUER (1984) observed that Mn fluxes to the sediment from the oxygen minimum zone (associated with sinking biogenic particles) are large enough to explain the high content of Mn in deep-sea sediments. The origin of Mn in the oxygen minimum zone was explained by the mechanism of Mn transport through an

1097

REEs in pelagic sediment

ma1 influence of the East Pacific Rise (EPR). The low La/ Sm ratio and negative Ce anomaly of fish bone debris in red clay (BERNAT, 1975) can explain the correlation between La/ Sm and Ce/Ce* of non-calcareous pelagic sediments observed in Fig. 8. This supports the idea that negative Ce anomalies in our samples are not due to hydrothermal influences. To summarize the above description, the two components that may cause negative Ce anomalies in Pacific pelagic sediments associated with high P, Mn, and REE contents are fish bone debris and hydrothermal oxyhydroxides of Fe and Mn. A more precise discussion on the relationship between the negative Ce anomaly and fish bone debris based on grain size analysis studies is given in the following section. 4. Chemical analysis of’ samples separuted by grain size

FIG. 7. The relationship between Ce anomaly and the content of manganese in siliceous sediments (calcium contents are below 8 wtW) of all samples in Appendix I.

oxygen minimum zone from the anoxic shelf/slope sediments. But upward diffusion of Mn in the sediment column by diagenesis could also be the mechanism of Mn enrichment in pelagic sedimenis having a Ce anomaly. The ratio of La/Sm in the sediment sample shows the degree of enrichment or depletion of light REEs. Figure 8 shows the relationship between Ce anomaly and La/Sm ratio in siliceous sediments (Ca content below 8%). The samples with a negative Ce anomaly have La/Sm ratios in the range of 3.0-4.5, while positive Ce anomaly samples have La/Sm ratios of 4.0-6.5. Thus, a positive correlation exists between Ce anomaly and La/Sm ratio. Cerium-depleted deep-sea sediments from the Southeast Pacific have a La/Sm ratio between 5 and 6.5 (COURTOIS and HOFFERT. 1977). The negative Ce anomaly and high La/ Sm ratios in these samples is probably due to the hydrother-

0.4

0.6

0.8

1.0

1.2

1.4

We chose a sample from KH70-2-9-3 (17”06’N, 146” 12%‘) obtained at 60-80 cm core depth as a typical negative Ce anomaly sediment for the determination of each of the categories divided according to the grain size. This sample has a significantly negative Ce anomaly (Ce/Ce* = 0.47). a low La/Sm value (La/Sm = 3.3) and a high REE content, about five times that of shale. The sampling location (see Fig. 4a) of this sediment is far from both the continental area and the EPR, and is under high biological productivity due to the combination of the California upwelling zone and the north equatorial current (Fig. 4a). We divided the core sample into categories A-F according to grain size, as shown in Figure 9. The shale-normalized REE patterns and chemical composition of the bulk sample and size separates (A-F) are shown in Fig. 9 and Table 1. The weight fractions A, B. C, D, E, and Fare 15, 18,46, 19, 1, and I % of total, respectively. Table 1 shows that fractions D and E have remarkably high contents of Ca, P. REEs, Y, and Th in comparison with the bulk composition and content of the other fractions. The high contents of Ca and P are due to an abundance of calcium phosphate in these fractions. Photomicrograph observation and electron microprobe analysis confirmed that crystals of calcium phosphate are abundant in fraction E from the KH70-2-9-3 core samples. In fractions C and D, the grains of fish bone debris were also found to be abundant by photomicrograph observation. Subsequent observation by microscopic observation on the coarse fractions of KH68-4- 15-3 (Ce/Ce* = 0.64), KH68-4-

1.6

Ce/Ce* Grain

FIG. 8. The relationship between Ce anomaly and La/Sm ratio in siliceous sediments (calcium contents are below 8 wt%) of all samples in Appendix I. Data ofsoutheast Pacific sediments are from Courtois and Hoffert (1977).

size

FIG. 9. Shale normalized REE patterns of bulk sample and of the samples in their A-F categories after grain size division. Samples are from the KH70-2-9-3 site ( 17”06’N, 146” 12’W; see Fig. 4a).

Table

1.

Chemical canpositions of the bulk sample of the KH 70-2-g-3 ( SLio-bttcm is GO - 80 cm ) ad grain size classes A-F.

depth

0.69 16.4 Fe Md

03

Na p2

0 8

5

1R

4G

19

0.72

ii.69

0.66

14.3

15.0

15.6

0.0

0.9

0.27

0.28

17.2

16.3

9.36

7.01

9.87

9.43

6.90

6.34

4.04

3.94

1.37

1.27

1.21

1.46

1.27

1.72

1.64

3.00 2.35

4.13

4.06

3.11

2.85

1.58

0.51

0.76

1.88

4.47

9.74

4.36 1.82

2.58 0.99

1.63 0.20

1.31

2.43 0.80

3.20

0.23

2.74

2.55 8.55

5.20 1.08

I.a(ppn)

124

42.5

2

168 -__

93.9 -__

41

11.8

sm

8.8 5.9 15.8

2.55 1.74

52.3 110 ___ 14.9 3.57 2.52

2.7

4.9 0.79

5.1 0.83

0.58

0.99

3.02

3.60

119

274

137

216

359

448 96.9

39.7 9.68 6.18 14.8

66.6

631 415

125

912 21.0

202

22.4

48.6

14.2

36.5

3.6

37.0

90.4

8.3

15.0

1.5

2.46

6.16

0.93

0.49

3.51

3.00

0.33 2.83

5.2

0.28

0.01

3.12

3.17

1800

1320

1450

2120

2680

2730

200

273

151

163

260

400

450

148

36

48

43

35

53

78

20

221

66

74

202

620

1260

140

117

134

129

100

89

94

49

42

43

54

60

112

770 17

192

172

162

189

152

250

189

346

257

278

442

450

708

674

12.8

20-2 (Ce/Ce*

15 0.73

100

Weight(%)

6.3

7.5

= 0..57), and KH71-5-12-3 (C&e* = 0.79) revealed abundant grains of fish bone debris. Figure 9 indicates that there is no Ce anomaly in the clay parts (~2 Frn; A and B fraction) of this sample, while the hydrothermal Fe-Mn oxides and smectite clays in the hydrothermal area have a negative Ce anomaly; the coarsest part (F fraction) also has only a little Ce anomaly. On the other hand, grain sizes in the lo- 100 Frn (D and E) fractions have significantly high REE contents and large negative C’eanomalies. The negative Ce anomafy in fractions C and D is due to fine grains of calcium phosphate. Figure 10 reveals a good correlation between P and Sm contents in fractions A-F and bulk samples. In normalizing shale, total REE is 204 ppm and Sm content is 7.5 ppm. The good correlation in Fig. 10 shows that the Sm/P20, ratio is in the range of 0.002-0.~3. implying a total REE/P ratio in the range of 0.02-0.03. This ratio indicates that the Sm content of pure apatite (about 40% P,O,) may be about 1000 ppm, which is as large as the ratio (Sm/P205 = about 0.003) among the bulk samples from various areas of the Pacific (Fig. 5). The Sm-P205 correlation trend in Fig. 5 indicates that this high REE content in the Pphase is common to pelagic sediments, as ELDERFIELDand GREAVES(198 1) have already mentioned. From the results shown in Figs. 5 and 10, we suggest that fish bone debris in red clays generally have about 100 times the REE concentration of shale. Fish bone debris in red clays reported in the data of BERNAT (1975), STAUDIGELet al. ( 1985/86), and WRIGHT et al. ( I987) have REE concentrations 50-250 times as high as the value in shale. The discrepancy between our data and some reported low values of

73.6

24.8

33.0

3.6

REE content in fish debris (SHAW and WASSERBERG,1985; GRANDJEANet al., 1987) is probably due to the differences in grain size and the sedimentation rates ofthe environments

Sm (PPrn,m) 1

:

:

:

:*

D”

&HJLK

50

6.

OA . 0

I .F 2

.

4

. 6

'-“'~~-----

P205 iY)

FIG. 10. The relationship between the content of samaritun and phosphorous in their A-F categories a&r grain size division. Samples are from the KH70-2-9-3 site (I 7”06W, 146”12W; see Fig. 4a).

1099

REEs in pelagic sediment

(ARRHENIUS et al., 1957; STAUDIGELet al., 1985/ 86; ELDERFIELDand PAGETT, 1986; TOYODA, 1987). The slow sedimentation rate of red clay results in the incorporation of a high content of fish bone debris with REEs. The biogenic apatite samples reported by SHAWand WASSERBERG(1985) GRANDJEAN,et al. ( 1987), and others, are collected mainly from continental margins, whereas our samples are deep-sea sediments. High contents of Th, Y, and REEs (Table 1) are thought to be derived from the substitution of these elements into the lattice in calcium phosphate. ARRHENIUSet al. (1957) suggested that high REE concentrations in fish bone debris make it highly probable that thorium is present in a considerable amount, because its geochemical behaviour is similar to that of REEs.

studied

IV. SUMMARY AND CONCLUSION 1. REE patterns in deep-sea sediments are characteristic of

various sediment types: cakareous ooze has a negative Ce anomaly and a depleted REE content compared to those of shales; anoxic blue mud has little or no Ce anomalies and a REE content similar to shales; red clay has both positive and negative Ce anomalies. The REE content in red clays with negative Ce anomalies is a few times that of shale, whereas red clay with positive Ce anomalies is similar in REE content to blue mud. The degree of Ce anomaly in red clay is independent of water depth of sampling location. The spatial distribution of the Ce anomaly in deep-sea argillaceous sediment may be summa~zed as follows: cerium anomalies are characteristic of pelagic sediments; red clay with a positive Ce anomaly is distributed in high and middle latitudes of the central Pacific; negative Ce anomalies are observed not only on and near the active spreading ridges, but also in the equatorial Pacific. High REE, P, and Mn contents (and depletion of light REEs) are characteristic of equatorial Pacific red clay sediments with negative Ce anomalies. A good correlation between REE and P content is observed. The Sm/P205 ratio of sediment samples in various areas of the Pacific is about 0.003. Microscopic observation and electron microprobe analysis revealed that fish bone debris are abundant in the red clay samples, display a negative Ce anomaly, and have significantly high REE and P contents. Chemical analysis of samples separated by grain size shows that the fish bone debris are the origin of the negative Ce anomaly in red clays. We consider that negative Ce anomalies in sediments, on and near the active spreading ridges, are related to hydrothermal activity at the spreading centers. However, in the case of pelagic sediments far from the ridges, the negative Ce anomaly has its origin in ftsh bone debris, and the distribution of the negative Ce anomaly is associated with upwelling zones and surface pr~u~ivity. A negative Ce anomaly in this area reflects the high primary productivity of overlying water. Acknowledgments-We thank Professor K. Kobayashi of the University of Tokyo for arranging sample collection. We also thank Pro-

fessor H. Wakita of University ofTokyo for valuable discussions and help in experimental arrangements. Editorial handling: E. R. Sholkovitz

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h

I IlN~

1o~oda.1 hakarnura. and 4. Masuda

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kta

50, 393-400.

F. and WASSERBERGG. J. (1985) Sm-Nd in marine carbonates and phosphates: Implications for Nd isotopes in seawater and crustal ages. G‘eochim. C’osmochirn. .4cta 49, 503-S 18. SHIMIZUH. and MAS~JDAA. (1977) Cerium in chert as an indication of marine environment of its formation. Nu/zrre 266, 346-348.

SHIMOKAWAI‘.. MASUDAA.. and 11~~4 K. t IY:.!; Karc eanh tic ments in the top samples of the (‘ore9 from Pacltl; &can floi~ Gcwchem. .J. 6, 75-8 I SI'IRNR. V. (1965) Rare earth dlstributlons tn the marmc %XIIIO~ ment. Ph.D. thesis, MIT. C-rsr!r>lcEL H.. DOYI.~ P., and ZI\LXFR A. ! IW~iSih)Sr and Xd isotope systematics in tish teeth. JCrrth Plcmn .SC I crf 76, 4% 46.

J.. CARPEN I’ER M. S \,.. C’Ol.l.i.\ :,.. and WILSOC R. S. (1984) Metal accumulation rates tn northwest Atlantic pelagic sediments. Geochim. Cormoc~hlrn. fctu 48. L935- 193X. ‘lbc, S.and ST~I~XBERG M. (1982) Distribution of rare earth element5 (REE) in size fractions of recent sediments of Indian Ocean. (‘&.n! (;c~olq~’62, 3 17-333. ‘fo‘,oDA K. (1987) Geochemical consideration on the deep-sea scdiments and ferromanganese nodules. Ph.D. dissertation. Unit ‘Tokyo (in Japanese). Vor.kov 1. I. and FOMrNA L. S.. (lY73) New data on the geochemistq of the rare earths in the Pacific ocean sediments. GPO~/~~!?Z /rlt/ 19. 1178-I 1x7. WAI\;G Y. L... 1~; Y.-G., and SCW~GII I R. A., ( 19x6) Rare earth element geochemistry of South Atlantic deep sea sediments: Ce anomaly change at 54 My. Geochim. C’osmochim kru SO, I3371355. WALLK~ H. E..THOMSON J.. WrI.soh T. R. S.. WEAVERP. P. I:.. Hrtis N. c’.. and HYDESD. J. ( 3988)Active diagenetic formation of metal-rich layers in N.E. Atlantic sediments. (;r~oc~hrmcij\mockirn. AUU 52. 1557-l 569. WIIITE W. M., DUPRE B., and VIDAL P. (1985) lsotope and trace element geochemistry of sediments from the Barbados Ridge Demerara Plain Region. Atlantic Ocean. Grod~im Cotmochim ~CYCI 49, 1875-1886. WR1CiH.r7.. S(XRADER H.. and HoLSL-R W. I‘. (lW7) Paleoredox variations in ancient oceans recorded by rare earth elements in fossil apatite. Gwchim Co.rmochim .4cta 51, 63 I-644. YANG H-S., N~LAKI Y., and SAK:\I H. (1986) The distribution ot ““Th and “‘Pa in the deep-sea surface sediments of the Pacific ocean. (;c,ochim Cosmochim .-ic/tr 50, 8 I-89 rHOMSON 7‘.

II01

REEs in pelagicsediment

APPENDIX I. Chnical cunpositienof piston core samples from the Pacificocean. RC: red clay f BM: blue mud / CD: calcar~s Location Water sediment sub-W&m Mno X%8-3-4

38"OO'N 5420 30'w

RC

ce/c!e* Lafsn

RareEarthElsimmks i ppn ) ~~~_______________________________________

1.04

0.13

0.19

1.26

5.2

25.6

42-46 112-116

1.30 1.40

0.28

0.61

0.26

0.56

0.84 0.95

3.7 3.7

64.5 55.9

120 117

48-50 62-66 108-112

1.48 1.53 1.56

0.50 0.53 0.60

0.82 0.81 0.89

0.67 0.66 0.64

4.0 3.7 3.6

61.4 76.3 78.2

50-52

67.2

4.91

7.1

0.64

2.8

15.8 13.2

3.8 3.1

2.9 2.1

6.0 4.9

0.96

91.6 115 113

14.9 20.5 20.5

4.1 5.3 5.3

2.9 3.9 3.6

8.6 10.2 10.6

1.4 1.6 1.7 0.9 1.0

165" KH68-4-S*

26'5l'N 17O"Ol' w

4520

ll"59'N 169"58'W

5050

KH68-4-l&3*

Ol"59'N 170"01'w

5470

RC

58-60 102-104

1.22 1.21

0.36 0.36

0.92 0.74

0.72 0.63

3.3 3.2

44.7 48.1

76.1 72.6

13.5 15.1

3.4 4.0

1.7 2.7

5.0 5.8

KH68-4-20-2*

OZ"28'S 17O"OO'W

5130

RC

50-52 SO-84 100-102 150-154

2.85 2.53 2.69 2.18

0.52 0.54 0.53 0.53

0.98 0.87 1.03 0.86

0.57 0.57 0.58 0.54

3.6 3.6 3.7 3.8

53.0 55.7 55.8 52.0

69.6 73.0 72.9 63.7

14.6

3.9 4.3 3.8 3.8

3.0 3.1 2.9 2.9

8.8 7.7 8.3 1.4

1.2 1.2 1.5 1.1

lO"57'S 169" 59' W

4400

SO-52 100-102

5.29 4.76

0.43 0.41

0.19

1.03 0.92

4.5 4.9

44.6

0.29

56.3

99.7 109

19"SP'S 170"02'w

5300

78-82 104-108

2.38 2.28

0.21 0.26

0.69 0.80

1.25 0.91

4.1 4.3

23.4 29.3

64.8

K-I68-4-29-2*

25"54'S 170"2O'W

5600

RC

so-52 100-105

1.90 2.59

0.23 0.24

0.79 0.80

1.20 1.15

4.2 4.1

28.2 25.9

74.4 65.6

KH68-4-31-3*

32"OP'S 169'56'W

5650

RC

42-46 90-94

2.40 1.33

0.14 0.10

0.55 0.47

1.30 1.31

4.4 5.2

23.5 25.2

KH68-4-37-2*

46'01's 169"53'W

5200

BM

54-58 104-108

2.65 2.24

0.16 0.16

0.088 0.10

1.12 1.10

4.4 4.6

XH68-4-39-2*

50=07'S 169" 59'W

5190

RC

50-54 98-102

1.47 1.57

0.11 0.11

0.083 0.12

1.21 1.23

KH68-4-55-3

54*14'S 155"12'E

4200

RC

150-152

2.04

0.61

0.92

KJi70-2-5-3*

38'26'N 170Q06'W

5245

RC

so-52 100-102

0.74 0.69

0.07 0.06

KKIO-2-7-3*

33"OZ'N 169"54'W

5420

RC

50-52 98-102 140-144

0.64 0.62 0.62

KH70-2-9-3

17"06'N 146"12'W

4950

RC

so-52 74-76 100-104

KH70-2-18-3

44'02'N 146'Ol'W

4910

BM

SO-52 100-102

KH71-1-9

01" 26'N 152"58'3

3805

a,

50-52 100-102

ICK71-1-12-1

01' 52‘N 147'02“E

4510

RC

SO-52 loo-102

KH71-1-12-2

Ol"53'N 147'02'E

4530

PL!

lZ"04'N

4740

KH68-4..15-3*

W60-4-22-2*

KH68-4-25-Z*

KH71-1-15

RC RC

RC RC

RC

13O"ll' E iiH71-5-2-2

KH71-5-7-2

16'59'N 146'03'W

4860

02' 34'N 146°00'W

4550

RC a3

15.5 14.9 13.5

0.83

10.0

3.5

1.2

3.7

11.5

3.2

1.7

4.6

0.4 0.53

1.7 1.7

0.9 0.8

3.3 3.0

0.52 0.46

6.7 6.3

1.7 1.8

1.2 1.1

3.5 3.2

0.53 0.43

66.4 68.6

5.3 4.8

1.3 1.5

0.75 0.92

2.6 2.7

0.44 0.40

28.9 25.1

70.4 59.2

6.5 5.4

1.4 1.3

0.96 1.00

2.7 2.4

0.38 0.35

5.1 5.2

32.0 29.4

81.4 75.2

6.3 5.6

1.55 1.44

1.2 0.9

2.7 2.6

0.45 0.29

0.95

4.9

53.9

108

11.0

2.7

1.8

4.6

0.66

0.23 0.29

1.32 1.37

5.2 5.5

35.5 36.2

98 102

6.8 6.5

1.7 ---

1.3 _-_

3.1 -__

--__-

0.084 0.089 0.085

0.28 0.49 0.50

1.50 1.37 1.55

6.5 5.0 5.7

32.6 38.7 37.1

97.3 108 118

5.0 6.6 6.5

1.1 1.5 1.5

0.93 0.96 0.96

2.8 2.9 3.0

0.48 0.53 0.52

1.09 2.19 2.35

0.86 0.92 0.99

1.36 1.33 1.23

0.48 0.44 0.47

3.7 3.4 3.3

29 39 37.3

7.8 9.1 8.6

5.8 6.7 5.9

2.25 2.49

0.24 0.18

0.30 0.10

0.97 0.97

4.8 5.4

26.2 31.5

53.8 63.3

5.4 5.9

1.27 1.50

0.93 1.19

2.46 2.62

0.37 0.36

0.23

109 133 125

58.5

119 138 138

16.1 16.7 15.7

2.6 2.8 2.8

0.14

0.46

0.57 0.64

4.8 4.4

12.6 24.0

15.2 33.6

2.6 5.4

0.68 1.3

0.47 0.90

1.63 2.8

-----

6.34 2.77

0.18 0.19

0.13 0.72

0.90 0.89

4.5 4.5

26.5 28.0

51.5 54.0

5.9 6.2

1.5 1.7

1.0 1.1

2.8 2.8

-----

50-52 100-102

2.20 3.53

0.17 0.19

0.46 0.16

0.88 0.91

4.2 4.2

26.2 26.8

50.7 53.8

6.2 6.4

1.6 1.7

1.0 1.2

2.6 2.8

--_ ---

SO-52 100-102

1.24 1.38

0.20 0.23

1.06 0.99

1.11

4.0

0.95

4.0

28.8 33.6

70.6 71.6

7.2 8.4

1.9 2.1

1.1 1.6

3.2 4.4

_----

50-52 100-102

9.01 8.36

0.13 0.14

0.11 0.11

1.05 1.02

4.5 4.7

14.3 15.5

32.4 33.7

3.1 3.2

0.88 1.03

_--

2.1

---

0.55

2.0

---

0.065 0.054

0.071 0.086

0.18 0.30

4.0 3.7

21.0 7.02

:::

3.0 1.9

0.81 0.49

0.59 0.28

1.4 1.15

SO-52 100-102

43.9 25.6

50.5 43.5

cxze.

0.22 0.19

I ------. - -_---__--_- ____ ------__-_--________..__... Location Core

No.

(Latitude

Km9itude)

Water

) Depth (m 1

Sediment

-.-. __..I .~__

Sub-imttar

Depth ICXl)

Typz

Cd0 (%I

PO5

Mno

cf,

(8)

t,x?/Ce* La/.%

Elements

Rare Extb ( Em! ) _____---____--___.....__....___...__:.:.._.~ ____ La

@

Sm

E?i

Th

i>

in,

‘V1'4 7fi:;

-____.__

__-_ KH71-5-10-2

04"58'S 146"03'W

4960

KH71-5-12-3

11"Ol'S 146"Ol' w

4810

KH71-5-15-2

20'23, S 148"02'W

4620

46'19's 127O46'W

4630

03

42-44 48-50

M/l-5-42-2

27'35'5 88"03'W

3690

03

48-50 278-280

KH71-5-44

21"__

____

RC

4-6 26-28

KH71-5-24-2

S

RC

50-52 100-102

4.35

1.46 1.62

1.94 1.67

0.29

3.7

4.18

0.27

3.7

154 164

101 102

42.i 44.5

12.3 12.8

8." 9.h

RC

50-52 100-102

3.39 3.43

2.02 2.07

3.55 3.61

0.56 0.79

4.3 4.3

239 230

137 142

56.2 53.5

15.0 i2.7

12.0 10.1

RC

3-6 48-50 102-104

5.66

1.10

176

34.5

10.1

6.9

Id.

0.56 0.79

3.9 4.1 3.9

133

2.50 1.58

1.60 4.01 3.17

0.59

3.54 2.67

192 126

239 224

47.1 32.5

!1.1 7.7

7.Y 5.'

18.0 3.1 1:,"'3 2.5

46.3 42.9

0.18 0.12

0.28 0.15

0.51 0.55

3.8 3.7

27.1 21.0

31.5 26.3

7.' 5.G

7.9 1.5

1.3 0.92

!.A6 --^ ?J _-_

51.0 54.0

0.11 0.12

0.39 0.31

0.46 0.42

4.9 4.6

16.8 16.1

16.3 14.3

3.4 3.5

0.89 0.95

0.71 0.73

.!.I? 0.35 2.16 0.35

8.98 4.75

1.05 1.11

2.58 2.65

0.59 0.55

4.0 4.1

25.9 8.34

0.24 0.60

1.24 2.08

0.38 0.36

4.8 4.1

43 94.4

91" -- w

s.4 4.7 2'7.i. 5.0 ---

138

180

34.5

8.73

6.2

18.L

3.4

153

185

37.1

9.45

7.:

27.1

3.7

35 74.3

8.9 22.8

2.3 3.8

1.9 2.7

>.4 7.'

0.92 1.24

a, RC

94-96 228-230

5820

RC

25-30 40-45

3.79 2.79

0.12 0.13

0.42 0.63

1.06 1.12

4.1 4.9

15.5 21.5

36.3 51.0

3.7 4.3

1-i 1.2

0.67 0.62

.!: 2.6

-----

21" 34' N 132'42'E

5360

RC

50-52 140-142

1.50 1.90

0.20 0.24

0.76 0.86

1.05 0.98

5.0 5.2

43.7 44.8

95.9 91.5

8.6 8.6

2.0 2.0

1.4 1.4

3.8 4.2

0.71 0.69

KH72-2-58

22"53'N 129'13'E

5300

RC

106-108 120-122

2.97 0.60

0.19 0.13

0.62 0.20

1.07 ____

5.2 _-_

39.4

87.0 86

7.4 ----

1.6 1.s

0.95 0.96

.l.i ?.9

0.57 0.41

KH73-4-5

12"23'N 151" 4$ E

5920

RC

50-52 100-102

1.21 1.13

0.30 0.29

1.09 1.05

1.02 1.08

4.4 4.3

51.9

115

11.5

3.1

2.i

1.6

..--

53.0

126

12.5

3.1

2.1

5.R

---

lO"46'N 153'42'E

5700

56-58 100-102

1.24 1.15

0.25 0.29

0.90 1.02

1.10 1.04

4.5 4.4

46.6

KH73-4-7

02"51 N 146"SO'E

4160

a,

loo-102

SC.6

0.085

0.18

3.33

4.6

9.3

KfJ73-4-8

Ol"33'S 167"39'E

4000

al

44-48 90-92

43.9 51.9

0.15 0.07

0.17 0.11

0.37 0.51

4.4 4.1

KH73-4-9

O7o6O'S 172"49'E

5390

RC

50-52 100-104 144-146

0.54 0.48 0.46

1.14 1.18 1.14

0.57 0.62 0.63

3.7 3.6 3.8

33"46'S 112"46'E

3040

0.036 0.021

0.28 0.37

6.2 5.9

KH76-2-3

24"27'N 132"35'E

4750

RC

32-34 98-100

1.32 1.16

0.12 0.14

0.50 0.40

1.07 1.10

5.7 5.8

35.8 37.0

KHBO-2-5

40'00'N 153'00' E

5510

RC

22-24

1.54

0.13

0.37

1.21

5.0

5650

RC

33-35

1.07

0.10

0.39

1.17

5550

RC

37-39 49-51

1.04 1.00

0.08 0.09

0.21 0.20

1.27 1.18

KH71-5-53-2

08'15'N 112"42'W

3380

KH72-2-2

31" 48'N 144'Ol'E

KH72-2-56

KH73-4-6

KH76-1-31

KHBO-2-6

39*03'N

RC

a,

48-50 92-94

4.00 3.54 3.16 56.5 56.7

---

36.2

86.2 105

7.9

2.0

1.5

‘1.7

0.79

10.4

2.9

2.1

4.w

0.91

6.5

2.0

0.51

0.30

'.L

0.20

18.6 7.9

14.9 6.83

4.1 1.9

1.11 0.56

0.79 0.37

2.3 1.4

0.38 0.23

48.1

62.1

11.8

3.7

2.9

1.7

I .._ 7

52.1 47.4

74.3 68.3

14.2 12.8

3.8 3.2

2.7 3.0

i.' 6.6

1.2 1.2

9.64

5.44

1.6

0.47

0.29

I.14

---

8.13

6.08

1.4

0.38

0.30

i.0

---

78.4 83.1

6.2 6.3

1.3 1.5

1.2 1.2

2.6 2.7

0.44 0,48

18.6

47.9

3.7

---

---

2.2

0.37

5.6

24.7

59.3

4.4

1.08

---

2.i

0.34

5.1 5.6

25.8 28.7

68.4 69.4

5.0 5.1

1.07 i.13

-----

2.2 2.4

0.39 0.43

166°00'E KHBO-2-8

38"03'N 179"46'W

1103

REEs in pelagic sediment APPlmDIX

II.

canposition of surface sea-sediment samples frcm the Pacific

&mica1

lcxation

Water

(Latitude (Imgitude)

) tkpth

Typs

KH78-3-4

53"30'N 177"ldE

3920

RC

o-3 ffi

1.85

KH79-4-10

03"19's 159"18 E

2090

w

o-2 BOX

52.1

0.11

ni79-4-12

31" 60'S 15Y18'E

1400

w

o-5 PG

51.8

m79-4-14

24"57'S 160" 37‘E

3640

w

o-2 o(;

KH79-4-18

00~01's 165" 09' E

4450

w

XH79-4-19

05Oo3's 163"55'E

4660

KHBO-3-19B

32"4l'N 158"04'E

KHBO-3-21

Sediment

Rare EarthElements ppn -~---~----~-~~--~~~~~~~~~~~~~~~~~~-~~~~~~~

(

Subtottan Ce/Ce*

Iafsn

1.00

3.6

6.1

15.6

0.065

---

5.3

4.9

----

0.09

0.056

0.50

5.9

5.6

44.8

0.13

0.15

0.45

5.0

o-2 Cc

39.5

0.19

0.19

0.46

w

o-2 OG

19.1

0.36

0.46

0.57

2600

W

D

52.8

0.13

0.26

0.83

4.7

7.4

31'44'N 157'27'E

3950

W

D

22.9

0.14

0.60

0.89

4.7

KH80-3-24B

13'42' N 148" 35'E

6100

03 RC

D D

11.4 2.81

0.23 0.72

0.36 0.86

0.56 0.75

KH80-3-34

26'24'N 143"OO E

1400

W

D

11.5

0.21

0.30

KH83-3-SC

43'18'N 154" 42'E

5400

RC

2-4 B3X

2.27

0.12

XH83-3-C

45"02'N 159"60'E

5600

RC

o-1 BOX

1.86

KH84-l-03

26 04'N 144 19'E

1150

RC

D

3.18

KH84-l-05

26'13'N 144'05'E

2400

W

D

KH84-1-25

20"20'N 143" 43'E

2850

W

XH84-1-26

26'13'N 144'll'E

1650

GH78-l-1036

08"OO'N 176'57'E

GH78-l-1038

10"OO'N 179' 59' E

Site

No.

Depth

ocean.

Cao

)

Id ce SnEulbYbLu ( m) (%) w KY (cm) ________________________________________-__-__----------_--_________------------____------_--______________________________ 0.55

0.28

0.98

0.21

0.92

0.26

0.19

0.91

0.51

5.7

0.94

0.26

0.21

0.88

0.16

9.8

9.2

1.9

0.6,

___

___

___

4.5

14.1

14.1

3.1

0.92

___

___

___

4.0

37.5

48.1

9.4

2.04

___

___

___

13.1

1.6

0.4

0.29

0.87

0.14

22.8

43.3

4.8

1.2

0.69

2.01

0.33

3.7 3.8

73.1 62.4

92.3 106

19.5 16.6

5.5 4.2

3.41 3.5

9.05 8.9

1.4 1.4

0.84

4.1

21.7

40.7

5.4

1.7

1.11

3.1

0.61

0.39

1.12

3.9

12.5

31.5

3.2

0.85

---

2.1

0.52

0.14

0.58

----

3.8

12.3

37.0

3.2

1.6

1.1

3.6

0.60

----

0.81

0.90

3.7

17.0

34.8

4.5

1.3

6.2

2.6

0.38

29.3

0.22

0.20

0.44

4.4

16.3

15.4

3.6

1.04

0.62

2.2

0.31

D D

21.4 22.5

0.20 0.22

0.46 0.45

0.65 0.64

3.7 3.7

13.4 15.5

20.0 22.5

3.6 4.1

1.06 1.24

0.73 0.85

2.3 2.8

0.32 0.49

W

D D

33.0 36.5

0.26 0.19

0.27 0.19

0.83 0.65

4.4 5.0

15.3 15.7

27.5 22.2

3.5 3.6

0.97 0.64

0.59 0.64

1.9 2.1

0.28 0.35

5250

W

o-4 BOX

18.9

0.33

0.45

0.62

3.6

32.7

46.7

8.9

2.22

----

4.9

0.77

6140

RC

o-4 OG

0.51

0.82

0.73

3.7

50.8

84.3

13.5

3.16

----

8.0

1.16

1.56

0.10

0.96

18.7

_______--__________________________-_-_______________-_-_-----_--___________---_-_--_____________----_________________________ Core sampler:

a;: okem grab, FG:

Pilot

gravity.

D: Dredged

sample.