23. MAJOR-ELEMENT CHEMISTRY OF ARGILLACEOUS …23. MAJOR-ELEMENT CHEMISTRY OF ARGILLACEOUS SEDIMENTS AT DEEP SEA DRILLING PROJECT SITES 442, 443, AND 444, SHIKOKU BASIN Ryuichi Sugisaki,

23. MAJOR-ELEMENT CHEMISTRY OF ARGILLACEOUS SEDIMENTS AT DEEP SEADRILLING PROJECT SITES 442, 443, AND 444, SHIKOKU BASIN

Ryuichi Sugisaki, Department of Earth Sciences, Nagoya University, Nagoya, Japan

ABSTRACTBulk chemical composition of 279 samples of argillaceous sedi-

ments from DSDP Sites 442, 443, and 444 in the Shikoku Basin (Leg58) was determined and interpreted. Chemical features indicate thatthe Shikoku Basin sediments are typically terrigenous and were de-rived mostly from the Japanese Islands. A local contribution fromoceanic islands, such as the Izu-Mariana Islands, to the basin sedi-ments is not as large as expected from geophysical evidence. TheNankai Trough cannot be a barrier against sediment influx to thebasin from the Japanese Islands. Except for Ca and Mn, the bulkchemical composition of the sediments is inherited from the sourcematerials, such as granites and volcanics in the Japanese Islands,without remarkable modification. Basal sediments immediately onthe basaltic basement, enriched in Mn and Fe, formed under the ef-fect of hydrothermal emanations related to volcanism. From thechemical composition of the sediments, using the formula ofBoström et al. (1976), the spreading rate of the Shikoku Basin at 17to 15 Ma is estimated to have been 1.7 cm/yr, which is not inconsis-tent with the rate determined from geophysical data.

INTRODUCTION

The Shikoku Basin is one of the most typical mar-ginal basins, and it may provide the evidence to evaluatehypotheses for the genesis of the marginal basins of thewestern Pacific. The character of the sediments in thebasin should constitute such evidence. Bulk chemicalcomposition of 279 samples from DSDP Leg 58 Sites442, 443, and 444 was determined and examined in thiscontext.

Sugisaki (in press b) has studied sediments of theJapan Trench cored during DSDP Legs 56 and 57, andthe chemical aspects of argillaceous sediments frompiston cores around the Japanese Islands have beenstudied during cruises of the Geological Survey of Japan(Sugisaki, 1978; Sugisaki, 1979, in press a; Sugisaki andHonza, in press; Sugisaki and Kinoshita, in press).

The present paper gives critical comparisons of thesedata and discusses the distribution of elements in argil-laceous sediments of the marginal basin, to examinepossible sources of the deposits.

ANALYTICAL PROCEDURE AND RESULTThe analytical procedure adopted in this study is the

same as that applied to the sediments of Legs 56 and 57by Sugisaki (in press b).

The distribution of the samples and the analytical re-sults are shown in Tables 1 through 5. Tables 6 through10 list the silicate compositions of samples recalculatedby excluding carbonate, salt, water, and residual materi-als (organic matter and others); these values are mostlyused in the following discussion.

GENERAL CHEMICAL CHARACTERISTICS OFTHE SEDIMENTS

CaCO3 was found in some of the samples and wasnot detected in others (Tables 1 through 5). This sug-gests that the depositional surface fluctuated above orbelow the calcium carbonate compensation depth (CCD)during the depositional history. Few data are availableconcerning present or past level of the CCD in the Shi-koku Basin, and the exact depth of deposition cannot bedetermined. Sugisaki (1978) inferred from piston coredata that the CCD in the Nankai Trough and its vicinityis at about 4500 meters. Present water depths at Sites442, 443, and 444 are 4639, 4372 and 4843 meters, re-spectively. CaCO3 was not found in the upper part ofthe cores at Site 442, but it was detected in the others.This evidence is not inconsistent with that for the Nan-kai Trough.

Table 11 lists the average silicate composition of thesediments at each site. They are closely similar. Further-more, almost all of the standard deviations are small,which shows a high degree of uniformity of the ar-gillaceous sediments through the entire sampled se-quences.

For comparison, several other sets of averages areshown in Table 11, representing piston-core sedimentsfrom the Philippine Sea far south of the Leg 58 area,pelagic sediments from the east Pacific Ocean, andargillaceous sediments from five regions around theJapanese Islands. The samples from the Oki area andthe Japan Trench are contaminated by quartz (Sugisakiand Kinoshita, in press) and biogenic silica (Sugisaki, in

719

R. SUGISAKI

TABLE 1Chemical Composition (%) of Argillaceous Sediments of Hole 442A

No.

12345

6789

10

1112131415

1617181920

2122232425

2627282930

3132333435

3637383940

4142434445

4647484950

5152535455

5657585960

6162636465

6667

686970

7172737475

7677

7879

Sample(interval in cm)

442A-2-1, 91-932-22-3, 60-622-4, 71-732-5, 13-15

2-6,36-383-2, 30-323-3, 46-483-4, 53-553-5,100-102

3-6, 127-1293-7,68-704-1,63-654-2, 105-1074-3, 20-22

4-4, 35-374-5, 7-95-1, 111-1135-2, 106-1085-3, 73-75

5-4,131-1335-5,118-1206-1,121-1236-2,10-126-3, 108-110

6-4, 45-476-5,10-126-6, 5-77-1,129-1317-2, 34-36

7-3, 34-367-4, 34-367-5, 34-368-4, 45-478-5, 45-47

10-3,11-1310-4,11-1311-3,6-813-2,100-10214-3, 99-101

15-2,69-7115-3,44-4615-4,9-1116-1,93-9516-2, 33-35

17-2,84-8618-2,135-13718-3, 7-919-1,130-13219-2,60-62

19-3,88-9020-1,100-10221-1,16-1821-2, 16-1821-3,16-18

21-4, 16-1821-4, 20-2222-1 ,CC23-1, 28-3023-3, 57-59

23-4,143-14523-5,16-1824-1,128-13024-2, 140-14224-3,50-52

24-4, 50-5224-5,50-5225-2,111-11325-3,126-12825-4,126-128

26-2,100-10227-2,124-12628-1, 62-6428-2, 53-552*1,88-90

29-330-1,51-5330-2, 22-2430-3, 76-78

SiO2

59.9660.3858.3657.2064.34

60.3960.7557.5258.9859.62

55.9757.9556.6759.3253.92

52.5056.4760.3656.9960.27

57.7560.6759.1758.3860.25

60.5860.6658.3057.5759.61

59.3863.8658.4358.8561.71

56.7058.2957.9751.6656.21

54.3756.9457.4056.9756.81

59.0756.9756.1656.2457.12

57.8055.8657.6258.2760.05

57.2658.0657.7755.5456.01

59.5058.4058.4258.1158.75

57.6457.9757.0057.0858.04

57.0656.1857.6454.9253.60

53.4253.5754.5651.01

TiO2

0.680.670.660.680.55

0.670.580.650.700.70

0.690.680.670.700.65

0.640.670.680.690.66

0.730.740.750.660.66

0.710.690.670.700.70

0.710.480.680.690.67

0.700.590.730.670.75

0.700.720.740.730.72

0.700.710.740.740.73

0.730.710.690.720.69

0.690.700.700.700.71

0.710.720.660.670.66

0.660.700.690.690.70

0.650.660.660.660.62

0.630.670.640.60

A12O3

16.0015.7415.4615.7915.49

16.0214.9715.3416.3416.33

16.3615.4315.8215.9714.73

14.3915.5717.0415.8815.75

16.3717.3916.3815.2615.99

16.8017.0915.6016.1816.84

16.7914.4016.4917.0516.11

16.6914.5317.4815.8617.28

16.4417.5717.1817.5317.22

16.7817.4516.7017.8117.73

17.6417.5817.3517.9317.80

17.1517.6617.5017.5417.16

18.1617.8116.6716.5517.55

16.6816.7316.8316.6916.95

16.0915.8816.2816.2414.58

15.0514.9515.7514.39

F e 2 O 3

3.583.733.623.262.69

3.522.953.303.303.23

3.533.503.663.933.40

3.563.283.503.963.68

3.483.223.613.323.54

3.723.723.614.233.41

4.332.413.623.924.02

4.375.333.713.394.53

4.764.865.444.724.45

4.984.955.135.385.31

5.435.405.405.575.45

6.276.305.544.985.37

5.355.775.015.115.51

5.295.495.665.575.48

5.716.186.416.188.63

7.618.518.199.41

FeO

2.302.012.272.331.90

2.312.022.112.382.46

2.242.192.222.172.17

2.002.142.152.082.05

2.262.332.342.122.06

2.182.002.122.022.22

2.041.602.202.081.97

2.131.672.242.371.96

1.611.721.531.641.78

1.541.711.421.531.51

1.511.381.411.461.39

0.490.491.071.581.29

1.491.301.131.110.81

1.201.531.341.511.65

1.411.601.501.190.16

0.560.080.050.04

MnO

0.100.110.120.150.10

0.120.240.280.130.21

0.150.270.170.170.35

0.200.200.230.230.37

0.630.180.190.430.43

0.250.270.310.450.38

0.490.110.360.410.37

0.410.930.252.700.29

2.010.120.240.110.42

0.210.360.900.350.51

0.440.720.200.130.17

0.720.640.310.911.02

0.130.160.500.610.48

0.5 80.160.321.210.25

0.530.510.420.440.28

0.740.851.241.67

MgO

2.452.252.182.291.82

2.462.032.532.262.46

2.462.462.372.522.39

2.302.232.442.452.30

2.662.642.562.362.52

2.622.282.362.672.71

2.841.672.692.692.58

2.922.802.833.472.66

3.512.632.342.332.69

2.632.732.592.812.79

2.892.802.392.662.56

2.432.492.643.263.20

2.432.682.482.712.47

2.552.032.293.012.46

3.132.772.653.233.75

3.614.174.294.29

CaO

1.341.511.450.841.25

1.452.350.911.201.41

0.070.5 71.681.170.62

0.550.311.311.250.14

1.100.141.020.091.36

0.351.191.250.940.02

1.091.100.401.171.28

1.110.221.010.831.07

0.101.041.210.870.98

1.361.661.540.120.55

0.220.701.141.181.21

0.930.970.860.090.18

1.181.251.640.471.72

1.782.271.700.182.47

0.851.641.011.832.22

2.682.271.751.62

Na2O

1.301.401.250.931.20

0.941.311.130.981.26

1.261.420.941.181.18

0.421.181.371.281.49

1.791.041.031.441.75

1.551.731.521.892.15

2.031.651.631.991.76

1.792.421.514.751.50

3.871.591.261.121.40

1.571.682.041.721.80

1.482.061.171.421.22

1.751.691.592.652.96

1.361.282.552.722.35

2.231.581.813.011.76

2.291.821.901.872.09

1.712.362.900.52

K 2 O

2.962.852.943.213.11

3.143.133.133.203.23

3.222.043.123.233.01

3.053.173.113.253.26

3.283.433.333.283.21

3.373.213.123.243.27

3.183.243.183.193.08

3.243.333.512.843.13

3.013.012.923.173.29

3.082.982.993.123.17

3.092.963.163.183.00

3.123.123.223.113.03

3.063.083.043.002.89

2.922.532.782.822.62

2.472.412.622.871.87

2.282.313.013.05

p 2θ5

0.130.140.130.110.11

0.110.090.110.110.12

0.100.130.110.120.13

0.110.110.130.110.10

0.110.100.110.110.17

0.110.130.110.120.12

0.120.080.110.130.12

0.120.090.111.150.12

0.120.110.110.120.12

0.130.160.190.130.15

0.140.170.150.120.17

0.140.140.160.140.16

0.130.140.180.180.18

0.180.140.130.130.14

0.150.150.140.170.24

0.230.200.280.51

H 2 O

6.5 15.306.596.866.47

5.675.705.015.366.51

7.416.627.556.416.54

5.755.765.977.055.32

5.175.566.445.966.91

5.486.506.837.286.82

6.075.786.035.975.97

5.656.376.666.017.42

6.237.136.477.386.07

5.706.424.585.606.36

5.806.627.136.596.01

6.876.987.336.466.58

6.307.016.776.356.24

7.155.864.603.374.60

5.775.985.626.067.07

8.068.147.047.16

CaCO3

0.00.00.03.120.0

0.00.0

3.730.00.0

4.334.910.00.0

7.73

11.035.770.00.03.33

0.01.900.0

3.630.0

1.500.00.00.00.0

0.00.03.470.00.0

0.0

1.550.03.620.0

2.010.00.00.00.0

0.00.00.0

2.191.46

1.871.730.00.00.0

0.00.00.02.422.09

0.00.00.02.090.0

0.00.00.03.040.0

3.042.072.140.00.0

0.00.00.00.0

Resid-ual*

1.550.941.671.530.09

0.391.411.232.351.49

0.940.260.450.170.18

0.200.190.182.070.16

1.930.180.110.660.08

0.190.201.650.320.47

0.351.750.290.820.14

1.720.140.660.720.90

0.040.77 (0.140.691.32

1.760.522.390.650.05

0.190.150.150.580.15

0.370.220.17 10.190.07 1

0.38 J0.21 10.49 10.11 10.17 1

0.39 11.00 12.72 11.67 ]1.70 1

0.03 10.13 10.10 ]2.71 12.14 ]

0.34 :

Salt

2.152.062.261.92

.85

2.071.722.00

.75

1.64

.84

.72

5.592.222.04

2.341.972.17

.921.95

.74

.482.04.48

2.13

.52

.47

.61

.43

.51

.56

.05

.30

.52

.23

.57

.52

.53

.37

.26

.64

).77'.07.73.79

.42

.89

.62

.36

.51

.69

.61

.21

.14

.09

.09

.47

.12

.09

.14

.12

.14

.43

.07

.19

.26

.01

.19

.21

.21

.30

.94

.90

.45

.80

.120.34 0.920.44 0.780.21 4.61

Total

101.0099.0998.95

100.22100.97

99.2799.2798.9899.05

100.67

100.57100.14

99.0399.2899.02

99.0499.04

100.6599.21

100.83

99.00101.01

99.0799.19

101.05

100.93101.14

99.0699.05

100.23

100.9799.19

100.88100.49101.00

99.1299.80

100.21101.40

99.08

100.4298.9899.0699.1199.05

100.94100.18

99.0099.74

100.75

100.91100.44

99.17100.95100.96

99.28100.92

99.97100.67100.96

101.29100.95100.98100.86100.98

100.5098.9999.07

101.19100.02

100.4799.92

100.9999.8199.05

99.0499.34

100.9399.10

'Residual materials were calculated by subtracting CO2 and H2O from ignition loss. They may contain sulfur, organic matter, and other materials.

720

MAJOR-ELEMENT CHEMISTRY

TABLE 2Chemical Composition (%) of Argillaceous Sediments of Hole 442B

No.

123456789

101112


442B-1-1, 76-781-2, 24-261-2,137-1392-1,36-382-2, 17-192-3, 9-112-4, 62-642-5, 47-493-1,48-503-2, 40-423-2,115-1173-3, 6-8

SiO 2

68.8555.6666.3647.4350.8651.1152.5853.5854.6249.5549.4750.66

TiO 2

0.350.650.460.570.590.580.620.620.600.510.430.48

A12O3

12.7115.7213.2112.8813.4413.8714.8814.7515.2611.5910.4311.84

F e 2 O 3

1.395.562.348.519.758.587.919.007.48

11.3114.66

9.82

FeO

0.771.391.290.030.050.120.120.110.100.400.080.08

MnO

0.0610.0260.411.161.991.581.471.670.743.542.672.66

MgO

0.692.831.033.704.985.214.614.453.824.184.446.07

CaO

1.672.162.221.961.811.891.671.631.231.241.370.96

Na 2 O

1.961.143.053.054.453.673.363.532.205.544.394.01

K 2 O

3.962.643.331.982.342.292.662.942.882.882.472.22

P2O5

0.110.160.130.320.350.310.190.290.180.240.150.16

H 2 O

4.023.234.926.387.188.707.265.177.778.027.179.23

CaCθ3

0.00.00.09.700.00.00.00.00.00.00.00.0

Residual*

1.235.561.120.711.710.770.932.290.800.331.140.61

Salt

1.262.421.091.791.611.800.940.801.420.931.051.90

Total

99.0399.14

100.96100.16101.11100.47

99.21100.83

99.11100.26

99.93100.69

*(See note at Table 1.)

press b; Sugisaki and Honza, in press), respectively. Thesamples from the Nankai Trough and its vicinity (Sugi-saki, 1978) and from the two areas of the Japan Sea,around the Yamato Bank (Sugisaki, 1979) and the Ni-shitsugaru Basin (Sugasaki, in press a), are typical ter-rigenous sediments. The average SiO2 content of theLeg 58 samples amounts to almost 64 per cent, which ismuch higher than that for the south Philippine Sea andeast Pacific Ocean. This indicates that the ShikokuBasin sediments are not typically pelagic, but resemblethe terrigenous sediments around the Japanese Islands.This shows an effect on the Shikoku Basin sediments ofsediment influx from siliceous continental crust. On theother hand, the SiO2 content of the sediments from theShikoku Basin is a little lower than that for the NankaiTrough. This indicates that the influence of continentalcrust on the sediments is reduced southward. In fact, thesediments of the Shikoku Basin are mostly derived fromthe Japanese Islands. This will be discussed later.

Another aspect of the Leg 58 samples is moderatelyhigh manganese content, much higher than in samplesfrom the regions around the Japanese Islands, andlower than in samples from the south Philippine Sea andthe east Pacific Ocean. This implies a moderate sedi-mentation rate in the Shikoku Basin compared to otherareas. Sugisaki (1978) suggested that sediments charac-terized by low Mn and high Si contents in the NankaiTrough and its vicinity gradually change into pelagicsediments with high Mn and low Si contents. The pres-ent data indicate that such change is proceeding in theregion of Leg 58.

HYDROTHERMAL ASPECT OF THEBASAL SEDIMENTS

The temporal variation in content of some oxides ateach site is illustrated in Figure 1. Lithologic units wererecognized according to color of the sediments, domi-nant paleontological and mineralogical components,and sedimentary structures. The deeper parts of thecores tend to be more enriched in Mn and Fe. The con-siderable increase in Mn and Fe in the oldest sedimentsis striking, especially at Site 442. The points represent-ing the oldest sediments at Site 442 in Figure 1 are theaverage values for four samples collected within 3meters of the basalt basement (Table 12).

The most likely explanation is that volcanic emana-tions are responsible for enrichment in Mn and Fe. Hy-drothermal emanations originating at mid-ocean ridgeshave been thought to provide a substantial source ofMn. Sediments enriched in Mn and Fe immediatelyoverlying volcanic basements are found to have been de-posited on or near an ocean ridge system with high heatflow (Boström and Peterson, 1969); hot fluids rich inFe, Mn, and other metals moved upwards throughlavas, giving rise to ferromanganoan deposits. Mineral-izing emanations enriched in Mn and in dissolved gaseswith a high ratio 3He / 4He were recently found in theGalapagos Rift Zone (Klinkhammer et al., 1977; Lup-ton et al., 1977). Furthermore, iron-rich mudstonescalled "umber," directly overlying pillow lavas of theTroodes Massif, Cyprus, are interpreted as precipitatesconnected with late stages of volcanism on a Cretaceousocean ridge (Robertson and Hudson 1973). Table 12also shows the chemical composition of red shale whichdirectly overlies pillow basalts in the Shimanto Belt,Cretaceous geosynclinal area, southwest Japan. Thesesediments are similar in their high contents of Mn andFe. The majority of the Shimanto shales are not asso-ciated with basalts and are impoverished in Mn and Fe.This can be considered evidence for a hydrothermal ef-fect on the basal sediments at Site 442.

On the other hand, the basal sediments at Sites 443and 444 are not remarkable for their concentrations ofMn and Fe. The sediments immediately on the basaltbasement at Site 442 are paleontologically dated at 15 to17 m.y., whereas those at Sites 443 and 444 are 14 to 15m.y. old (Klein et al., 1978). This suggests that thehydrothermal activity waned before deposition at thelatter sites.

Boström (1973) empirically found a relationship be-tween the composition of basal sediments and spreadingrates at plate-generating zones. The relationship is ex-pressed by the following formula (Boström et al., 1976):

(Fe + Mn)/Al = 0.59 exp (0.53 SR)

where SR is the spreading rate in cm/yr. If this formulais applied to the Shikoku Basin sediments, the spreadingrate at Site 442 is 1.7 cm/yr, and that at Sites 443 and444 is 0.5 cm/yr.

According to the estimation by Kobayashi and Naka-da (1978) on the basis of magnetic-anomaly data, the

721

R. SUGISAKI

TABLE 3Chemical Composition (%) of Argillaceous Sediments of Hole 443

No.

12345

6789

10

1112131415

1617181920

2122232425

2627282930

3132333435

3637383940

4142434445

4647484950

5152535455

5657585960

61626364

65


443-1-1,125-1271-4,108-1102-1, 71-732-3, 45-473-1, 16-18

3-2, 77-793-5, 84-864-1,111-1134-2,109-1114-3, 39-41

4-3, 45-475-1,61-635-2, 36-385-3, 99-1015-4, 31-33

6-2, 44-466-3, 44-466-4, 44-466-5, 44-468-4, 106-108

8-5, 58-609-3, 28-309-5, 26-2810-1,69-7110-1, 138-140

10-2,39-4110-2,138-14010-3,43-4510-4,51-5310-4,135-137

10-5,48-5010-5,132-13410-6,108-11011-2,108-11011-3,108-110

11-4,108-11011-5, 108-11011-6,70-7214-4,120-12214-5,120-122

14-6,106-10815-4,48-5015-5,63-6515-6,63-6515-7,28-30

17-4,11-1318-1,98-10018-2,98-10018-3,98-10021-2,13-15

23-1,110-11223-2, 95-9723-3, 40-4223-4, 50-5224-1, 70-72

24-3,42-4424-3, 90-9224-4, 95-9724-5, 71-7324-6, 74-76

25-2, 72-7425-2,123-12525-3, 86-8826-1, 82-8426-2,142-144

SiO2

52.0657.7758.1159.1160.37

61.8957.3058.7252.8861.80

56.0356.9355.8053.2757.43

58.0242.8962.9457.4353.95

57.3553.3658.5658.1157.91

60.1658.0057.4358.4556.95

56.0054.0559.2952.0453.01

59.0358.7959.2557.4858.86

59.7359.2356.3057.2257.47

52.8156.1259.4764.2256.04

56.6159.3756.7259.9655.66

54.9156.3155.2650.6346.67

50.1345.6956.5657.1450.11

TiO2

0.610.650.680.720.73

0.730.670.660.620.72

0.660.710.690.640.58

0.600.500.630.660.65

0.710.670.710.670.65

0.620.650.640.660.66

0.660.660.540.630.63

0.690.640.710.710.65

0.700.760.700.720.71

0.700.680.610.420.72

0.700.630.480.540.69

0.700.720.690.660.61

0.850.570.690.670.64

A12O3

14.8815.9215.4814.5214.92

15.0813.8713.9314.7816.76

15.6016.2915.8414.8014.89

15.5511.6416.0115.7815.08

16.2715.3316.7116.8415.90

15.0215.8515.8715.9716.07

16.0014.6714.6814.6214.73

16.2516.0016.3216.8516.23

16.5317.7216.6317.1016.89

15.9516.1816.3013.9517.19

16.7016.1714.8915.8316.58

16.6816.4216.5814.6613.98

14.2913.4516.3416.2714.19

F e 2 O 3

3.583.333.793.583.30

3.023.353.423.743.06

3.093.483.693.662.91

3.022.992.633.453.61

3.513.803.573.943.90

3.823.954.294.323.86

4.203.924.293.423.94

3.613.533.554.164.05

3.333.194.474.114.06

3.774.383.472.074.71

5.154.143.503.955.19

4.864.735.135.414.75

5.154.245.014.804.80

FeO

2.032.282.142.422.34

2.422.312.152.052.41

2.142.302.252.122.20

2.041.572.052.122.28

2.281.992.221.972.01

1.901.972.071.932.12

1.971.951.812.012.07

2.112.052.242.251.99

2.282.262.192.152.16

2.112.031.891.471.75

1.481.721.241.381.66

1.671.951.772.401.39

4.401.452.092.212.07

MnO

0.530.290.440.160.20

0.160.560.430.460.17

0.340.250.410.350.37

0.360.560.110.200.44

0.330.250.190.280.27

0.270.290.270.240.26

0.300.420.120.360.60

0.170.380.140.300.08

0.160.140.600.300.28

0.450.470.140.170.55

0.360.350.310.330.51

0.280.370.390.230.61

0.220.530.320.380.48

MgO

2.942.382.713.083.06

2.963.192.662.482.39

2.362.642.792.692.01

2.061.741.942.282.33

2.852.472.652.442.50

2.502.142.572.312.68

2.692.632.312.272.61

2.642.472.522.582.20

2.122.432.912.802.66

2.462.812.011.142.97

2.802.481.662.123.14

2.892.692.992.842.46

3.022.382.732.532.53

CaO

0.610.390.630.161.05

0.130.330.021.420.15

0.180.410.140.072.67

0.265.481.300.600.03

0.400.270.150.130.34

1.640.601.380.690.17

0.400.180.070.460.19

0.210.201.301.081.22

0.550.270.370.240.30

0.161.050.181.200.24

0.251.580.290.190.87

0.491.250.431.930.30

4.510.302.302.580.13

Na2O

2.051.601.821.611.32

1.041.771.421.261.11

1.531.771.631.781.99

2.122.011.841.581.10

1.381.051.241.531.36

1.531.831.361.891.49

1.661.691.351.972.29

1.551.841.611.751.38

1.571.571.951.521.16

1.351.861.311.881.72

2.991.841.531.581.74

1.211.661.891.171.27

0.881.831.301.671.78

K 2 O

3.043.053.083.423.47

3.453.373.313.043.22

3.013.283.183.002.93

2.902.493.143.053.13

3.323.043.343.053.05

2.933.103.073.113.11

3.183.023.453.102.97

3.223.373.113.273.29

3.123.383.323.333.18

3.153.043.342.733.21

3.213.213.173.352.89

3.032.792.812.112.53

1.042.362.452.522.32

P2O5

0.120.150.170.120.13

0.110.120.120.110.13

0.150.130.110.120.12

0.130.130.100.130.16

0.120.170.110.120.12

0.110.110.110.130.12

0.110.120.0820.130.17

0.110.110.110.110.097

0.120.130.130.120.13

0.110.120.100.0830.12

0.120.130.0980.0950.15

0.140.130.140.120.15

0.091.630.120.130.12

H 2 O

4.074.304.105.352.62

4.385.192.715.204.72

3.566.376.475.116.59

4.334.656.306.275.45

5.806.265.665.846.51

6.206.707.926.216.54

5.964.915.954.864.68

6.416.725.886.785.53

5.785.965.845.926.69

6.035.086.884.296.49

6.776.354.867.146.72

5.956.686.693.345.24

2.462.716.315.693.22

CaCθ3

9.211.941.471.880.0

1.905.516.085.741.72

6.882.954.887.712.73

6.7914.67

0.03.858.01

3.058.013.522.202.78

0.03.100.02.063.08

4.178.713.41

12.739.47

2.011.700.00.0

o.α2.492.031.291.461.67

8.082.802.473.172.00

2.060.08.001.883.20

3.231.322.25

10.2318.84

10.4020.87

2.850.0

14.46

Resid-ual*

2.862.452.831.484.10

1.910.222.522.910.52

1.850.770.252.130.28

0.655.710.910.281.29

0.781.080.200.540.01

1.020.530.470.320.42

0.090.400.580.351.09

1.720.801.090.392.38

0.450.580.400.670.14

0.611.770.101.480.35

0.300.911.240.220.16

1.370.640.851.320.18

0.462.170.361.221.69

Salt

2.002.572.671.461.46

1.632.192.272.342.13

2.181.451.351.671.79

1.851.361.081.321.95

1.461.531.131.541.59

1.341.541.581.661.53

1.881.701.141.391.52

1.361.371.291.401.21

1.211.211.481.371.56

1.501.581.290.971.42

1.021.190.931.041.18

1.631.411.511.961.86

1.101.291.641.201.09

Total

100.5999.07

100.1199.0699.06

100.8299.96

100.4299.03

101.00

99.5799.7299.4899.1299.48

100.6998.39

100.9999.0199.45

99.6099.2899.9699.2098.89

99.05100.36

99.0399.9599.07

99.2799.0299.07

100.3499.97

101.1099.9799.1399.1199.17

100.14100.87

98.5899.0399.06

99.2499.9799.5699.2499.48

100.52100.08

98.9299.60

100.33

99.0599.0899.3899.02

100.85

99.00101.47101.07

99.0199.64

722


TABLE 3 - Continued

No.

6667686970

7172737475

7677787980

8182838485

8687888990

9192939495

96979899

100

101102103104105

106107108109110

111112113114


443-27-1,80-8227-2, 22-2427-3, 11-1327-4,55-5728-1, 108-110

28-2,16-1829-1, 87-8929-2, 61-6329-3, 85-8729-4, 56-58

29-5, 46-4830-2, 132-13431-1, 119-12131-2, 62-6431-3,44-46

31-4,44-4631-5, 30-3232-1,129-13133-1,38-4033-2, 38-40

33-3, 38-4034-2,11-1334-3, 11-1334-4,11-1334-5,11-1335-1,56-5835-3, 7-936-1,36-3836-2,103-10536-3, 89-91

36-4,114-11636-5,87-8939-1,76-7839-1,129-13139-2,50-52

40-1,56-5840-2,10-1242-1, 66-6842-2,13-1543-1,38-40

43-2,78-8045-1,79-8145-2, 67-6946-1,44-4646-2, 44-46

47-1,36-3848-1,129-13149-2, 25-2749-2,114-116

SiO2

60.3255.3757.6455.6260.30

58.3557.2156.9656.6458.03

57.0057.1057.6457.5656.84

56.6759.4952.5252.3962.57

51.9855.6248.2745.4255.45

45.0748.7446.4742.5640.41

55.6546.1954.0149.5439.78

55.8856.8656.8956.2959.01

59.0957.7660.8545.3556.59

57.9443.4555.1335.90

TiO2

0.580.650.590.680.69

0.670.650.670.670.61

0.670.630.660.670.66

0.650.630.650.760.40

0.640.550.560.480.64

0.410.590.600.560.52

0.650.570.670.600.48

0.680.670.630.640.60

0.610.660.580.590.66

0.620.470.570.45

A12O3

14.8815.6515.8916.3717.20

16.9416.5717.2616.8917.08

16.7415.6015.9516.1215.35

15.4215.1214.9314.5413.54

14.1013.9913.2811.9814.75

10.9813.1512.8411.9611.56

16.0812.5315.1313.7410.22

16.1216.0215.4515.2715.04

14.5714.9314.5911.4614.72

14.9010.8613.749.67

Fe2O3

3.805.231.564.955.13

5.124.755.104.564.98

5.394.645.064.964.84

4.914.904.704.712.85

4.704.414.813.654.13

3.515.094.774.564.82

5.404.784.974.583.74

6.265.966.195.524.83

4.315.494.545.536.21

6.084.719.156.99

FeO

1.941.491.411.481.44

1.381.461.441.601.71

1.531.621.862.102.34

1.952.022.282.261.63

1.921.651.551.262.05

1.531.831.871.801.37

1.781.582.021.711.39

1.641.641.461.871.63

2.121.852.071.601.81

1.741.320.550.30

MnO

0.280.831.330.250.10

0.290.430.370.390.39

0.540.670.130.480.45

0.540.470.510.250.22

0.350.250.400.370.16

0.340.360.290.361.55

0.121.210.190.483.01

0.170.360.610.490.20

2.270.510.0930.770.75

0.130.500.510.73

MgO

2.102.902.982.432.20

2.522.462.642.5 82.65

2.743.062.442.862.90

2.822.542.432.311.35

2.122.252.241.542.31

1.532.271.902.102.62

4.132.542.512.772.43

2.852.893.252.712.64

2.333.012.202.543.17

2.871.714.073.27

CaO

0.620.530.121.190.96

1.030.191.110.491.52

0.080.782.461.911.44

1.721.032.241.752.38

1.831.631.530.881.81

0.470.844.446.887.56

2.670.670.760.184.41

2.232.221.570.411.86

2.541.172.660.621.08

2.150.070.444.52

Na2O

2.072.283.641.101.04

1.521.821.084.771.90

2.082.391.652.711.97

2.292.022.342.152.50

2.081.892.031.741.86

1.991.511.511.722.64

1.432.041.561.943.85

1.571.282.302.011.60

1.752.271.692.053.00

1.521.421.270.59

K2O

2.342.852.943.003.08

3.122.833.053.042.99

2.882.742.432.302.42

2.512.512.042.083.36

2.222.272.162.042.03

2.222.122.001.952.06

2.732.372.532.591.88

2.732.723.062.882.91

2.872.622.791.942.42

2.572.032.661.85

P2O5

0.120.160.210.150.13

0.140.130.120.140.15

0.140.160.130.140.14

0.140.120.120.160.085

0.130.110.140.110.11

0.0950.120.0980.120.10

0.0830.0970.0860.101.11

0.130.140.110.120.11

0.190.140.110.190.12

0.100.160.110.14

H2O

6.525.943.957.626.35

5.576.796.275.615.96

6.285.656.935.165.19

6.064.065.225.085.47

4.666.334.752.814.35

2.735.695.774.744.30

6.515.614.535.704.07

7.306.906.456.866.73

5.896.055.984.585.78

6.423.836.896.15

CaCO3

2.264.014.250.00.0

0.01.980.01.370.0

2.993.270.02.572.40

1.862.617.419.350.0

11.026.43

15.2623.01

7.41

27.2315.0413.2014.1914.05

0.018.428.09

15.0121.00

0.00.00.02.780.0

0.02.150.0

20.563.08

0.028.32

3.7628.11

Resid-ual*

0.171.072.322.161.45

1.580.691.170.951.86

0.000.250.560.551.19

0.330.430.850.311.68

0.280.350.842.420.71

0.761.371.804.555.14

0.890.140.440.313.59

0.580.161.600.050.68

0.730.210.270.200.12

0.840.710.521.78

Salt

1.311.371.121.100.85

1.091.151.841.211.19

1.231.051.150.991.23

1.201.201.151.021.03

1.051.321.201.371.24

1.071.861.311.181.90

1.801.891.521.571.41

1.342.061.451.541.21

1.571.251.101.071.29

1.211.200.560.55

Totat

99.32100.3399.9498.09

100.93

99.3299.1099.08

100.92101.03

100.2999.6199.05

101.0899.36

99.0799.1599.3899.1099.06

99.0899.0599.0299.0799.01

99.93100.5798.8799.23

100.60

99.92100.6499.03

100.82102.37

99.4799.88

101.0199.4599.05

100.84100.0799.5299.05

100.80

99.08100.7699.93

101.00


spreading rate of the Shikoku Basin was 4 to 6 cm/yrbetween 26 and 22 Ma, and it subsequently decreased toabout half that rate (2-3 cm/yr). Rates after 18 Ma seemto vary with time and place. Watts and Weissel (1975)estimated the rate between 22 and 19 Ma to be 2.2cm/yr. The rate estimated from chemical parameters atSite 442 is apparently not inconsistent with the geo-physical estimate for the last period of spreading.Spreading slowed during deposition of the basal sedi-ments at Sites 443 and 444 (15-14 Ma), if the chemicalparameters provide a valid indication.

POSSIBLE SOURCES OF THE SEDIMENTS IN THESHIKOKU BASIN

Seismic profiles obtained by Murauchi and Asanuma(1977), Karig (1975), and others showed that there arethree coalescing clastic wedges in the basin. A wedge onthe north side of the basin was penetrated at DSDP Site297; a second, on the west side of the basin, waspenetrated at Site 442; and the third, on the east side,was penetrated at Sites 443 and 444. The direction ofthickening of these wedges suggests that the north

723

R. SUGISAKI

TABLE 4Chemical Composition (%) of Argillaceous Sediments of Hole 444

No.

123456789

10111213141516171819


444-3-1, 12-143-2, 22-243-3, 20-224-1, 116-1184-2, 116-1184-3, 20-224-3, 114-1165-1,76-785-2, 92-945-3,60-625-4, 68-707-1,50-527-2, 77-797-3, 43-457-4, 12-147-6, 28-309-1,110-11210-1, 52-5410-2,52-54

SiO2

59.4056.1058.7057.5859.2857.9356.0458.9056.0756.5256.9657.8658.0960.0762.1057.5560.7158.6056.22

TiO2

0.680.680.730.720.700.730.670.720.690.740.700.720.720.650.640.720.640.640.68

A12O3

16.1015.8316.1316.2415.8916.3715.3415.7016.1216.8216.4216.5516.6215.2216.0716.7414.8216.0816.34

Fe 2 O 3

3.544.053.913.594.244.634.614.154.544.143.644.814.763.483.744.593.354.384.75

FeO

2.272.092.221.992.061.971.482.541.742.202.831.721.851.811.632.112.671.711.70

MnO

0.260.770.170.210.130.170.600.210.220.480.200.250.210.330.160.130.150.190.32

MgO

2.583.542.592.782.592.522.112.332.453.052.642.502.682.082.192.382.182.622.91

CaO

0.570.350.660.110.580.210.682.560.610.311.011.701.602.121.832.003.801.751.73

Na2O

1.942.101.301.591.571.382.431.931.371.921.741.581.952.861.861.172.021.951.67

K2O

2.953.193.123.293.053.192.902.453.143.113.082.892.972.743.032.852.202.733.00

P2O5

0.140.130.140.120.140.120.150.130.130.150.160.150.140.130.120.160.150.140.15

H2O

5.055.105.835.465.666.255.055.125.995.285.996.426.876.196.135.445.207.316.61

CaCO3

1.813.531.262.081.591.683.990.06.282.152.010.00.00.00.00.00.00.00.0

Residual*

0.191.720.521.270.170.941.490.830.071.380.030.390.410.260.361.390.330.511.23

Salt

1.521.591.781.791.661.371.501.361.511.591.591.531.501.101.251.691.091.451.78

Total

99.00100.7699.0798.8299.3099.4699.0398.92

100.9299.8599.0099.08

100.3799.03

101.1098.9299.31

100.0599.09


wedge was probably derived from the Japanese Islands,whereas the west and east wedges were derived from theKyushu-Palau Ridge and the Iwo Jima Ridge, respec-tively. Geochemical data obtained in the present studycan be used to evaluate these possibilities.

The relationships among SiO2, TiO2 and A12O3 (Fig-ure 2) are helpful in the examination of the sedimentsource, because these components tend to remain in theresistates and hydrolysates during sedimentation (e.g.,Rankama and Sahama, 1950), and their relative abun-dances are preserved during weathering. The points inFigure 2 fall along a line connecting points for averagedJapanese granites and averaged Quaternary volcanics.Points for averaged shales in the Shimanto Belt (Creta-ceous geosynclinal area) and the Chichibu terrain (Pale-ozoic geosynclinal area), the Japanese Islands, also plotnear the line. The point for Izu-Mariana volcanics plotsoff the line; this strongly suggests that the ShikokuBasin sediments were mostly derived from the JapaneseIslands, and not from the Izu-Mariana Islands. Sedi-ments from the east Pacific Ocean and the PhilippineSea plot in an area of lower silica. The SiO2 content ofNankai Trough sediments, which were also derived fromthe Japanese Islands (Sugisaki, 1978), is a little higherthan that of the Leg 58 samples (Table 11). Silica in sedi-ments off the coast of southwest Japan tends to de-crease southward, probably because of the influence ofoceanic and basic materials derived from islands such asthe Izu-Mariana islands. Such local contribution to theShikoku Basin sediments, however, is not as large as ex-pected from seismic evidence. The closely similar plotsfor the three sites on the ternary diagrams of Figure 2reinforce the inference.

The temporal variation in SiO2 content at each site israther small and does not show any trend (Figure 1), in-dicating continuous influx of terrigenous sedimentsfrom the north. Karig (1975) presumed that the Pliocenedevelopment of the Nankai Trough as a sediment trapreduced or completely eliminated the supply of the sedi-

ments from the north. However, the geochemical dataof the sediments show that the Nankai Trough cannothave been a barrier to sediment influx from the north.

CHEMICAL ALTERATION OF THE SEDIMENTS

The sediments must have undergone some alterationduring diagenesis. To what extent was the original com-position of the sediments changed? The sediments in theJapan Trench were observed to be considerably con-taminated by biogenic silica (Sugisaki, in press c) andthey are not suitable for evaluating chemical alteration.On the other hand, Shikoku Basin samples with a smallamount of silica contamination will serve the presentpurpose.

Figure 3 exemplifies the relationships among TiO2,total Fe as Fe2O3, and MgO. The averaged variations ofthese elements in granites and volcanics in the JapaneseIslands were plotted in the figure together with someaveraged sediments from various regions. General as-pects emerge from the plot: (1) Most sediments of theShikoku Basin, which plot between the averaged volcan-ics and granites, originated in the Japanese Islands, (2)A local contribution, for example from the Izu-Mari-ana islands, falls short in explaining the origin ofsediments of the Shikoku Basin as a whole, (3) Thevariation trend of these elements in the present samplesis closely similar to those for the granites and volcanics.SiO2, TiO2 and A12O3 have been cited as elements mu-tually stable during weathering; in addition, the relativeconcentrations of Mg, Ti, and Fe in the sediments wereinherited from the source materials without remarkablemodification.

Examination of trends for other elements leads us tothe conclusion that Si, Ti, Al, total Fe, Mg, and Kbehave as conservative elements, while Ca, Mn, andFeO/Fe2O3 change remarkably during the sedimentaryprocesses. Fe2O3 is negatively correlated with FeO (Fig-ure 4) and positively correlated with total Fe, indicatingoxidation.

724


TABLE 5Chemical Composition (%) of Argillaceous Sediments of Hole 444A

No.

12345

6789

10

1112131415

1617181920

2122232425

2627282930

3132333435

3637383940

4142434445

4647484950

5152535455


444A-1-1, 64-661-2, 64-661-3, 64-661-4, 64-661-5, 64-66

1-6, 64-662-2, 92-942-3, 23-252-4, 23-253-2, 62-64

3-3, 62-643-4, 62-643-5, 62-646-1, 38-406-2, 38-40

6-3, 38-406-4, 38-406-5, 38-407-1,56-588-1,69-71

9-1, 28-309-2, 28-309-3, 28-309-4, 28-309-5, 28-30

10-1, 104-10610-2, 104-10611-1,112-11411-2,118-12011-3,115-117

11-4,60-6212-1,94-9612-2,119-12113-1,91-9313-2,68-70

13-3, 30-3214-1,73-7514-2, 73-7514-3, 73-7514-4, 26-28

15-1,44-4615-2,44-4615-3,44-4616-1,44-4616-3, 74-76

21-1,122-12421-2, 33-3521-2, 35-3721-2, 39-4122-1, 75-77

22-2, 75-7722-3, 95-9722-3,99-10122-4, 84-8623-1, 24-25

S1O2

57.0455.6839.7954.8958.88

56.8761.4059.6156.0755.77

55.3555.4957.5857.7155.14

54.8558.0857.1456.1956.80

55.5554.9354.4055.9454.92

52.0355.3865.7359.4059.46

54.6246.5252.2754.7755.37

55.9556.3962.5669.0056.42

58.2267.0860.9255.8462.08

60.3357.1957.8459.4261.30

60.9257.4555.0951.8247.79

Tiθ2

0.700.680.530.690.67

0.660.470.590.680.71

0.740.710.710.650.65

0.690.680.670.700.71

0.660.720.710.740.72

0.760.650.420.630.40

0.560.630.660.740.73

0.700.660.580.450.66

0.650.400.620.650.50

0.490.650.630.610.61

0.510.640.640.600.50

A12O3

17.7115.8212.0216.1917.03

16.1712.5115.9116.1916.55

16.2116.5716.4317.1316.95

16.3117.0117.1816.8117.09

15.6115.5715.0815.0815.21

13.9313.4412.8915.3811.43

14.2413.1114.2315.3015.69

15.1714.8713.2611.5015.66

16.2712.0515.0215.8412.69

14.4914.6114.4814.3013.25

13.6914.4213.5913.2911.24

F e 2 O 3

4.864.684.054.684.76

4.882.754.024.905.11

4.765.325.045.935.78

6.305.465.566.226.24

5.775.735.705.105.27

6.193.541.943.772.07

3.884.275.475.795.70

5.564.512.571.105.06

4.641.734.415.872.95

3.825.845.134.462.67

3.476.616.725.504.88

FeO

1.931.941.111.741.85

1.711.541.941.981.63

2.201.711.671.041.11

1.111.011.281.111.19

1.752.572.673.113.31

3.332.911.622.381.60

2.692.782.443.462.84

2.782.732.731.931.97

2.271.712.092.461.49

2.052.312.472.312.88

2.011.651.781.771.39

MnO

0.240.210.320.340.21

0.290.150.110.330.35

0.330.420.390.360.35

0.490.390.320.410.30

0.420.570.530.300.26

0.220.190.140.190.15

0.210.260.170.170.31

0.160.240.140.0790.21

0.260.120.160.100.15

0.100.210.210.210.20

0.330.391.170.520.54

MgO

2.952.511.692.602.66

2.401.312.312.532.90

2.872.972.772.942.55

2.792.612.693.053.01

2.543.543.603.103.27

3.142.111.442.191.29

2.392.793.033.362.92

2.982.801.950.632.74

2.811.092.473.331.72

2.843.833.162.932.00

2.254.065.184.101.95

CaO

0.592.320.090.941.49

2.142.061.952.682.50

2.791.172.421.961.85

1.861.522.142.091.70

3.224.504.083.174.53

4.613.502.583.770.78

3.290.564.105.723.95

3.362.343.472.562.81

4.102.612.693.263.57

1.973.633.603.573.13

1.531.860.332.150.21

Na 2O

1.621.831.081.241.44

1.862.081.392.401.98

2.151.832.261.821.73

1.942.161.971.921.66

0.122.862.452.292.20

1.292.212.422.022.12

1.611.681.791.511.44

1.531.632.282.471.73

2.222.341.421.341.73

1.281.801.791.772.79

2.101.833.261.872.73

K 2O

3.032.462.562.922.78

2.741.882.932.512.53

2.322.622.562.732.66

2.682.952.652.702.58

2.071.781.821.611.72

1.341.242.041.831.72

1.921.931.771.401.98

2.172.031.531.732.38

1.942.032.062.402.82

3.202.272.162.192.31

2.592.842.592.482.22

P2O5

0.170.150.200.160.15

0.160.0840.120.180.17

0.190.180.170.180.19

0.140.180.160.170.14

0.140.160.140.540.14

0.120.130.0970.140.081

0.140.120.140.130.13

0.130.150.130.0820.16

0.180.0830.130.120.097

0.120.170.180.180.12

0.110.110.120.110.20

H 2 O

6.016.013.738.275.59

5.955.705.756.916.85

4.895.426.615.697.04

7.816.006.917.346.82

6.056.556.065.875.99

4.564.544.874.664.03

5.792.775.034.835.56

5.795.815.415.297.14

5.735.266.515.557.35

5.674.465.095.564.19

4.846.404.117.483.51

CaCO3

2.432.57

29.222.441.30

0.04.880.00.00.0

0.02.240.00.00.0

0.00.00.00.00.0

0.00.00.02.350.0

6.848.850.00.0

11.92

4.7419.54

5.740.00.0

0.02.530.00.00.0

0.00.00.00.00.0

0.00.00.00.00.0

2.260.03.684.44

20.00

Resid-ual*

0.140.430.530.300.21

1.701.090.891.430.18

2.870.640.231.111.34

0.321.330.320.000.75

0.020.050.480.570.05

0.410.451.881.470.32

1.371.251.000.350.53

1.320.921.222.540.75

0.511.460.511.211.47

1.521.631.520.672.77

1.381.081.411.051.44

Salt

1.591.812.072.882.13

1.501.321.511.361.88

1.341.591.521.781.69

1.751.531.371.421.78

5.241.431.391.211.46

1.781.120.981.231.69

1.881.702.101.641.77

1.461.861.261.611.46

1.191.031.581.340.70

1.140.970.920.830.82

1.011.521.282.240.94

Total

101.0199.1099.00

100.28101.16

99.0399.2399.04

100.1499.11

99.0198.88

100.37101.03

99.02

99.04

100.92100.36100.14100.76

99.15100.97

99.12100.9999.04

100.55100.25

99.0599.0699.06

99.3399.9199.9399.1898.93

99.0599.4799.08

100.9899.14

101.0098.99

100.5999.3099.32

99.0299.5899.1899.0299.04

98.99100.86100.95

99.4399.55

*Residual materials were calculated by subtracting CO2 and H2O from ignition loss. They may contain sulfur, organic matter, and other materials.

The emphasis in a majority of mineralogical and geo-chemical studies has been on the role of chemical andmechanical sorting during weathering and sedimenta-tion. Nevertheless, the bulk chemical composition ofsediments, except for some elements such as Mn andCa, may remain essentially unchanged over a vastregion, although elements may migrate locally withinthe region.

ACKNOWLEDGMENTS

The author wishes to thank Dr. S. Mizutani, NagoyaUniversity, and Dr. H. Okada, Shizuoka University, for their

review of the manuscript. Thanks are also to Dr. K. Koba-yashi, University of Tokyo, for providing valuable informa-tion. A part of the expenses of this study was defrayed by aGrant in Aid for Scientific Research of the Ministry of Educa-tion, Japan.

REFERENCES

Aramaki, S., Hirayama, K., and Nozawa, T., 1972. Chemicalcomposition of Japanese granites, Part 2. Variation trendsand average composition of 1200 analyses. /. Geol. Soc.Japan, 78, 39-49.

725

R. SUGISAKI

TABLE 6Chemical Composition (%) Recalculated by Excluding Carbonates, Residual Materials, Water, and Salts, Hole 442A

No.

12345

6789

10

1112131415

1617181920

2122232425

2627282930

3132333435

3637383940

4142434445

4647484950

5152535455

5657585960

6162

SiC-2

66.0466.5065.9965.9169.51

66.2667.1766.1165.8465.50

65.0466.8964.8265.5665.33

65.8666.1765.3864.6466.91

64.0566.0365.3966.7565.54

65.6865.2565.5263.9565.19

63.8570.4865.0763.8565.88

62.8764.6163.4657.6062.81

60.0863.0563.5163.7963.21

64.1762.3662.1262.5362.51

63.2661.8363.5462.9064.08

62.9662.9463.2361.3661.49

63.6463.08

TiO2

0.750.740.750.780.59

0.740.640.750.780.77

0.800.780.770.770.79

0.800.790.740.780.73

0.810.810.830.750.72

0.770.740.750.780.77

0.760.530.760.750.72

0.780.650.800.750.84

0.770.800.820.820.80

0.760.780.820.820.80

0.800.790.760.780.74

0.760.760.770.770.78

0.760.78

A12O3

17.6217.3417.4818.1916.74

17.5816.5517.6318.2417.94

19.0117.8118.0917.6517.85

18.0518.2418.4618.0117.49

18.1618.9318.1017.4517.39

18.2118.3817.5317.9718.42

18.0515.8918.3618.5017.20

18.5116.1119.1317.6819.31

18.1719.4619.0119.6319.16

18.2319.1018.4719.8019.40

19.3119.4619.1319.3618.99

18.8619.1419.1619.3818.84

19.4219.24

F e 2 O 3

3.954.104.093.762.90

3.873.273.803.693.54

4.104.044.194.344.12

4.463.853.794.494.09

3.863.503.993.803.85

4.034.004.064.703.73

4.662.664.044.254.29

4.855.914.063.785.06

5.265.386.025.284.95

5.415.425.685.985.81

5.955.975.966.015.81

6.896.826.065.515.89

5.736.23

FeO

2.532.212.572.682.05

2.532.232.422.662.70

2.602.532.542.402.63

2.512.512.332.362.28

2.512.542.592.422.24

2.362.152.382.242.43

2.191.772.452.262.10

2.361.852.452.642.19

1.781.901.691.841.98

1.671.871.571.701.65

1.651.531.551.581.48

0.540.531.171.751.42

1.591.40

MnO

0.110.120.140.170.11

0.130.270.320.150.23

0.170.310.190.190.42

0.250.230.250.260.41

0.700.200.210.490.47

0.270.290.350.500.42

0.530.120.400.450.40

0.461.030.273.010.32

2.220.130.270.120.47

0.230.391.000.390.56

0.480.800.220.140.18

0.790.690.341.011.12

0.140.17

MgO

2.692.482.462.631.97

2.702.252.912.522.70

2.862.852.712.782.89

2.882.612.652.772.56

2.952.872.822.692.74

2.842.452.662.972.97

3.051.853.002.922.75

3.243.113.103.862.97

3.882.912.592.612.99

2.862.992.873.123.06

3.163.102.642.872.73

2.672.702.893.603.51

2.602.89

CaO

1.481.661.640.971.35

1.592.601.041.341.55

0.080.651.921.290.75

0.700.371.421.420.16

1.220.161.130.111.48

0.381.281.401.040.02

1.171.210.451.271.37

1.230.241.110.931.20

0.111.151.340.971.09

1.481.821.700.140.60

0.240.771.261.271.29

1.021.050.940.100.20

1.261.35

Na2O

1.431.541.421.081.30

1.041.451.301.091.38

1.461.641.081.311.43

0.531.391.491.461.65

1.981.141.131.651.90

1.681.861.712.102.35

2.181.821.812.161.88

1.992.681.665.301.67

4.271.761.401.261.55

1.711.832.261.911.97

1.622.281.291.541.31

1.931.831.742.933.25

1.451.39

K 2 O

3.263.143.323.703.36

3.453.463.603.573.55

3.742.353.573.573.65

3.833.713.373.693.62

3.643.733.683.753.49

3.653.453.513.603.58

3.423.583.543.463.29

3.593.693.843.173.50

3.333.333.233.553.66

3.353.263.313.473.47

3.383.283.483.433.20

3.433.383.523.443.33

3.273.33

P2O5

0.140.150.150.130.12

0.120.110.130.120.13

0.120.150.130.130.16

0.140.130.140.130.11

0.120.110.120.130.19

0.120.140.120.130.13

0.130.0910.120.140.13

0.130.110.121.280.13

0.130.120.120.130.13

0.140.180.210.150.16

0.150.190.170.130.18

0.150.150.180.160.18

0.140.15

Fe2θ3/FeO

1.561.851.591.401.41

1.521.461.571.391.31

1.581.601.651.811.57

1.781.531.631.901.80

1.541.381.541.571.72

1.711.861.702.101.54

2.121.511.651.882.04

2.053.191.661.432.31

2.962.823.562.882.50

3.232.893.613.523.52

3.603.913.833.813.92

12.7912.85

5.183.154.16

3.594.43

Total Fe

6.766.566.946.745.19

6.685.756.496.646.55

7.006.847.017.017.04

7.256.636.387.116.62

6.646.326.866.496.34

6.666.396.717.206.43

7.104.626.766.766.63

7.477.976.796.717.50

7.247.507.907.327.15

7.277.507.427.877.65

7.787.677.697.767.46

7.497.417.377.457.47

7.507.79

726


TABLE 6 - Continued

No.

636465

6667686970

7172737475

76777879

SiO2

63.3063.6962.92

62.8663.6262.9462.1162.74

63.1662.5663.1861.3060.88

60.3559.5658.8858.56

TiO2

0.720.730.71

0.720.770.760.750.76

0.720.730.720.740.70

0.710.740.690.69

A12O3

18.0618.1418.80

18.1918.3618.5918.1618.32

17.8117.6817.8518.1316.56

17.0016.6217.0016.52

F e 2 O 3

5.435.605.90

5.766.026.256.065.92

6.326.887.036.909.81

8.599.468.84

10.80

FeO

1.221.220.87

1.311.681.481.641.78

1.561.781.641.330.18

0.630.090.050.05

MnO

0.540.670.51

0.630.180.351.320.27

0.590.570.460.490.32

0.840.951.341.92

MgO

2.692.972.65

2.782.232.533.282.66

3.473.092.903.604.26

4.084.634.634.93

CaO

1.780.511.84

1.942.491.880.192.67

0.941.831.112.042.52

3.032.521.891.86

Na2O

2.772.982.52

2.431.732.003.271.90

2.532.022.082.082.37

1.942.623.130.60

K 2 O

3.293.293.10

3.182.783.073.072.83

2.732.682.873.202.12

2.582.573.253.50

P2O5

0.200.200.19

0.200.150.140.140.15

0.170.170.150.190.27

0.260.220.300.59

Fe2θ3/Fe(

4.444.606.80

4.41 .3.594.223.693.32

4.053.864.285.19

53.95

13.59106.39163.89235.14

3 Total Fe

6.796.956.86

7.227.897.907.897.90

8.068.868.868.37

10.01

9.309.568.90

10.85

TABLE 7Chemical Composition (%) Recalculated by Excluding Carbonates, Residual Materials, Water, and Salts, Hole 442B

No.

123456789

101112

Siθ2

74.4263.3070.7258.1456.1357.3058.3757.8861.2954.4754.6356.95

TiO2

0.380.740.490.700.650.650.690.670.670.560.470.54

A12O3

13.7417.8814.0815.7914.8315.5516.5215.9317.1212.7411.5213.31

F e 2 O 3

1.516.322.49

10.4310.76

9.618.789.728.39

12.4316.1911.04

FeO

0.831.581.370.040.060.130.130.120.110.440.090.09

MnO

0.0660.0300.441.422.201.771.631.800.833.892.952.99

MgO

0.743.221.104.535.505.845.124.814.294.594.916.82

CaO

1.812.462.372.402.002.121.851.761.381.361.511.08

Na2O

2.121.303.253.734.914.113.733.822.476.094.844.51

K2O

4.283.003.552.432.582.572.953.183.233.172.732.50

P2O5

0.120.180.140.390.390.350.210.310.200.260.170.18

F e 2 O 3

FeO

1.814.001.81

283.56195.09

71.4765.8981.8074.7928.26

183.26122.76

TotalFe

2.438.074.02

10.4710.83

9.768.939.858.52

12.9216.2911.14

Boström, K., 1973. The origin and fate of ferromanganoanactive ridge sediments. Acta Univ. Stockholmiensis, Stock-holm Contr. GeoL, 27, 149-243.

Boström, K., and Peterson, M. N. A., 1969. Origin of alumin-ium-poor ferromanganoan sediments in areas of high heatflow on the East Pacific Rise. Mar. GeoL, 7, 427-447.

Boström, K., Joensuu, O., Valdes, S., Charm, W., and Glac-cum, R., 1976. Geochemistry and origin of East Pacificsediment samples during DSDP Leg 34. In Yeats, R. S., etal., Init. Repts. DSDP, 34: Washington (U. S. Govt. Print-ing Office) pp. 559-574.

Geological Survey of Japan, 1960. Geology and Mineral Re-sources of Japan.

Goldberg, D. E., and Arrhenius, G. O. S., 1958. Chemistry ofPacific pelagic sediments. Geochim. Cosmochim Acta, 13,153-212.

Karig, D. E., 1975. Basin genesis in the Philippine Sea. InKarig, D. E., Ingle, J. C , Jr., et al., Init. Repts. DSDP,31: Washington (U. S. Govt. Printing Office), pp. 857-880.

Klein, G. D., Kobayashi, K., Chamley, H., Curtis, D. M.,Dick, H. J. B., Echols, D. J., Fountain, D. M., Kinoshita,H., Marsh, N. G., Mizuno, A., Nisterenko, G. V., Okada,H., Sloan, J. R., Waples, D. M. and White, S. M., 1978.Off-ridge volcanism and seafloor spreading in the ShikokuBasin. Nature. 273, 746-748.

Klinkhammer, G., Bender, M., and Weiss, R. F., 1977.Hydrothermal manganese in the Galapagos Rift. Nature,269, 319-320.

Kobayashi, K., and Nakada, M., 1978. Magnetic anomaliesand tectonic evolution of the Shikoku Inter-Arc Basin. J.Phys. Earth, 26 (supplement), S391-S4O2.

Lupton, J. E., Weiss, R. F., and Carig, H., 1977. Mantlehelium in hydrothermal plumes in the Galapagos Rift.Nature, 267, 603-604.

Murauchi, S., and Asanuma, T., 1977. Seismic ReflectionProfiles in the Western Pacific, 1965-1974: Tokyo (Univ.of Tokyo Press).

Ono, C , 1976. Average chemical compositions of rocks andtheir graphic representation. 4. Mudstone of the Honshugeosyncline. Bull. GeoL Surv. Japan, 27, 519-533.

Rankama, K., and Sahama, H., 1950. Geochemistry: Chicago(Univ. Chicago Press).

Robertson, A. H. F., and Hudson, J. D., 1973. Cyprus um-bers: chemical precipitates on a Tethyan ocean ridge. EarthPlanet. Sci. Lett., 18, 93-101.

Sugisaki, R., 1976. Chemical characteristics of volcanic rocks:relation to plate movements. Lithos, 9, 17-30.

, 1978. Chemical composition of argillaceous sedi-ments on the Pacific margin of southwest Japan. CruiseRepts. GeoL Surv. Japan, 9, 65-73.

727

R. SUGISAKI

TABLE 8Chemical Composition (%) Recalculated by Excluding Carbonates, Residual Materials, Water, and Salts, Hole 443

No.

12345

6789

10

1112131415

1617181920

2122232425

2627282930

3132333435

3637383940

4142434445

4647484950

5152535455

5657585960

Siθ2

63.1465.8065.2666.5066.42

68.0165.9867.6263.8367.24

65.8564.5664.4964.5765.19

66.6459.5767.9065.8065.19

64.7964.7665.4765.2465.81

66.4765.5564.4865.1665.08

64.2464.8867.3864.2363.70

65.8965.7865.2063.4965.36

66.2165.0362.8663.8664.57

63.6163.2466.9571.8962.81

62.6564.8067.6167.1362.49

63.2163.2562.7461.6262.46

Tiθ2

0.740.740.760.810.80

0.800.770.760.750.78

0.780.810.800.780.66

0.690.690.680.760.79

0.800.810.790.750.74

0.690.730.720.740.75

0.760.790.610.780.76

0.770.720.780.780.72

0.780.830.780.800.80

0.840.770.690.470.81

0.770.690.570.600.77

0.810.810.780.800.82

A12O3

18.0518.1317.3816.3316.42

16.5715.9716.0417.8418.24

18.3318.4718.3117.9416.90

17.8616.1717.2718.0818.22

18.3818.6018.6818.9118.07

16.6017.9117.8217.8018.37

18.3517.6116.6818.0517.70

18.1417.9017.9618.6118.02

18.3219.4618.5719.0818.98

19.2118.2318.3515.6219.27

18.4817.6517.7517.7218.61

19.2018.4418.8217.8418.71

F e 2 O 3

4.353.794.264.033.63

3.323.863.944.523.33

3.633.954.264.443.31

3.474.152.843.964.36

3.964.613.994.424.43

4.224.464.824.824.42

4.824.714.874.224.73

4.033.953.914.594.50

3.693.504.994.594.56

4.554.943.912.315.27

5.694.524.174.425.82

5.605.325.836.596.35

FeO

2.462.602.402.722.57

2.662.662.482.472.62

2.512.612.602.572.50

2.342.182.212.432.76

2.582.422.482.212.28

2.102.232.322.152.42

2.262.342.062.482.49

2.362.292.472.492.21

2.532.482.452.402.43

2.542.292.131.651.96

1.641.881.481.551.86

1.922.192.012.921.86

MnO

0.640.330.490.180.22

0.180.650.500.560.19

0.400.280.470.420.42

0.410.780.120.230.53

0.370.300.210.310.31

0.300.330.300.270.30

0.340.500.140.440.72

0.190.430.150.330.099

0.180.150.670.340.32

0.540.530.160.190.62

0.400.380.370.370.57

0.320.420.440.280.82

MgO

3.572.713.043.463.36

3.263.683.062.992.60

2.782.993.223.262.28

2.372.412.102.612.82

3.223.002.962.742.84

2.762.422.882.583.06

3.093.152.622.813.14

2.942.762.782.852.44

2.352.673.243.122.99

2.973.162.271.283.33

3.102.711.972.373.53

3.333.023.403.463.29

CaO

0.730.450.700.181.16

0.150.380.021.720.16

0.210.460.170.083.03

0.307.621.400.690.03

0.450.330.160.140.39

1.810.681.550.770.20

0.460.210.080.570.23

0.240.221.431.191.35

0.610.300.410.270.34

0.191.180.211.350.27

0.281.720.350.210.97

0.561.400.492.350.41

Na2O

2.481.822.041.811.45

1.152.041.641.521.20

1.792.001.882.162.25

2.432.791.991.811.33

1.561.281.391.711.54

1.692.061.532.111.71

1.912.031.542.442.75

1.732.061.781.931.53

1.741.722.181.701.30

1.622.101.482.101.93

3.312.011.821.771.95

1.401.862.141.431.70

K 2 O

3.693.473.463.853.82

3.793.883.813.673.50

3.543.723.683.643.33

3.333.463.393.493.78

3.753.693.733.423.47

3.243.503.453.473.55

3.653.633.923.833.57

3.593.773.423.613.65

3.463.713.713.723.57

3.793.433.763.063.60

3.553.503.783.753.24

3.493.133.192.573.39

P2O5

0.150.170.190.140.14

0.120.140.140.130.14

0.180.150.130.150.14

0.150.180.110.150.19

0.140.210.120.140.14

0.120.120.120.150.14

0.130.140.0930.160.20

0.120.120.120.120.11

0.130.140.150.130.15

0.130.140.110.0930.140.130.140.120.110.17

0.160.150.160.150.20

Fe2θ3/Fe(

1.771.461.771.481.41

1.251.451.591.831.27

1.441.511.641.731.32

1.481.901.281.631.58

1.541.911.612.001.94

2.012.012.072.241.82

2.132.012.371.701.90

1.711.721.591.852.03

1.461.412.041.911.88

1.792.161.841.412.69

3.482.412.822.863.12

2.912.432.902.263.41

) Total Fe

7.086.676.937.056.49

6.276.826.697.276.25

6.436.857.157.306.08

6.086.575.306.667.42

6.827.296.756.886.97

6.556.947.407.217.11

7.337.317.166.977.50

6.656.506.657.366.95

6.506.267.707.257.26

7.377.486.274.147.45

7.516.605.826.147.89

7.747.758.069.838.42

728


TABLE 8 - Continued

No. Siθ2 Tiθ2 AI2O3 FeO MnO MgO CaO K2O P2O5 Fe2O3/FeO Total Fe

6162636465

6667686970

7172737475

7677787980

8182838485

8687888990

9192939495

96979899

100

101102103104105

106107108109110

111112113114

59.2761.3962.9162.8663.29

67.7362.9665.2763.7865.35

64.0664.6563.4361.7263.07

63.4863.8863.7662.7063.6163.2465.4861.9762.8568.8563.3465.7362.7265.3965.0066.1463.6260.5257.0753.7361.3461.9463.9663.3355.0261.9162.6562.1763.8165.2663.7863.8966.0262.4362.5063.9465.1462.5155.74

1.010.770.770.740.810.650.740.670.780.750.740.730.750.730.66

0.750.700.730.730.740.730.690.770.910.440.780.650.730.690.750.600.770.780.750.690.720.760.790.770.660.750.740.690.730.660.660.730.630.810.730.680.700.650.70

16.9018.0718.1717.9017.92

16.7117.8017.9918.7718.64

18.6018.7319.2218.4018.56

18.6417.4517.6417.5617.1817.2116.6417.6217.4414.90

17.1816.5317.2517.2517.29

16.1117.1616.7216.0415.37

17.7216.8017.9217.5614.1417.8617.6516.8817.3116.63

15.7316.5115.8315.7816.26

16.4416.2815.5815.01

6.095.695.575.286.06

4.275.951.775.675.56

5.625.365.684.975.41

6.005.195.605.405.425.485.405.545.653.13

5.725.216.255.254.84

5.156.646.216.116.41

5.956.415.895.855.17

6.936.566.766.265.34

4.666.084.937.616.86

6.717.07

10.3710.85

5.201.952.322.432.61

2.181.691.601.701.56

1.521.651.601.741.86

1.701.812.062.292.62

2.182.222.692.711.79

2.341.952.011.812.40

2.252.392.442.411.82

1.962.122.392.191.92

1.821.811.602.121.80

2.292.052.252.202.00

1.921.980.620.47

0.260.710.360.420.61

0.310.941.510.290.11

0.320.490.410.430.42

0.600.750.140.520.50

0.600.520.600.300.24

0.430.300.520.530.19

0.500.470.380.482.06

0.131.620.230.614.16

0.190.400.670.560.222.450.560.101.060.830.140.750.581.13

3.573.203.042.783.20

2.363.293.372.792.39

2.772.782.942.812.88

3.053.432.693.123.24

3.152.802.862.771.48

2.592.662.912.212.71

2.252.962.482.823.48

4.553.412.983.543.36

3.163.193.553.072.92

2.513.332.393.503.51

3.172.574.615.08

5.330.402.562.840.17

0.700.600.131.361.04

1.130.211.240.541.65

0.090.872.722.081.62

1.921.132.652.102.62

2.231.931.991.262.13

0.691.095.789.23

10.05

2.940.900.900.236.10

2.472.451.720.472.06

2.741.302.890.851.20

2.370.100.507.01

1.042.461.441.832.25

2.322.594.121.261.13

1.672.051.205.202.07

2.322.671.822.962.21

2.552.222.762.582.75

2.532.232.632.512.18

2.921.971.962.313.51

1.572.731.852.485.32

1.741.412.512.271.77

1.892.511.832.823.32

1.682.121.430.92

1.233.172.732.772.93

2.633.243.333.443.34

3.433.203.403.313.25

3.213.072.692.512.71

2.802.762.412.503.70

2.712.682.812.942.38

3.262.772.602.612.74

3.013.183.003.312.60

3.023.003.343.263.22

3.102.903.032.672.67

2.843.043.022.87

0.112.190.130.140.15

0.140.180.240.170.14

0.150.150.130.150.16

0.160.180.140.150.16

0.160.130.140.190.094

0.160.130.180.160.13

0.140.160.130.160.13

0.0910.130.100.131.54

0.140.150.120.140.120.210.160.120.260.130.110.240.130.22

1.172.922.402.172.32

1.963.511.113.343.563.713.253.542.852.91

3.522.862.722.362.07

2.522.432.062.081.75

2.452.673.102.902.02

2.292.782.552.533.52

3.033.032.462.682.69

3.823.634.242.952.96

2.032.972.193.463.43

3.493.57

16.6323.29

11.877.868.157.998.976.697.833.547.567.297.307.207.466.917.487.907.207.897.948.337.907.878.538.665.138.327.378.487.277.517.659.298.928.808.43

8.138.778.558.287.30

8.958.578.538.627.34

7.208.357.42

10.069.08

8.849.27

11.0711.37

, 1979. Chemical composition of argillaceous sedi-ments around the Yamato Bank in the Japan Sea. CruiseRepts. Geol. Surv. Japan, 13, 75-88.

, in press a. Chemical composition of argillaceoussediments around the Nishitsugaru Basin in the Japan Sea.Cruise Repts. Geol. Surv. Japan.

, in press b. Major element chemistry of the JapanTrench. In Langseth, M., et al., Init. Repts DSDP, 56, 57:Washington (U. S. Govt. Printing Office).

Sugisaki, R., and Honza, E., in press. Chemical compositionof argillaceous sediments in the Pacific margin of northeastJapan. Bull. Geol. Surv. Japan.

Sugisaki, R., and Kinoshita, T., in press. Chemical composi-tion of argillaceous sediments around the Oki Islands, theJapan Sea. Cruise Repts. Geol. Surv. Japan.

Sugisaki, R., Suzuki, T., Kanmera, K., Sakai, T., and Sano,H., 1979. Chemical composition of green rocks in the Shi-manto Belt, southwest Japan. /. Geol. Soc. Japan, 85,455-466.

729

R. SUGISAKI

TABLE 9Chemical Composition (%) Recalculated by Excluding Carbonates, Residual Materials, Water, and Salts, Hole 444

No.

12345

6789

10

1112131415

16171819

SiO2

65.6863.1665.4665.2765.70

64.9364.4164.2964.3963.19

63.7363.7763.4265.6666.52

63.6665.4964.5562.83

Tiθ2

0.750.770.810.820.78

0.820.770.790.790.83

0.780.790.790.710.69

0.800.690.700.76

A12O3

17.8017.8217.9918.4117.61

18.3517.6317.1418.5118.81

18.3718.2418.1516.6417.21

18.5215.9917.7118.26

F e 2 O 3

3.914.564.364.074.70

5.195.294.535.214.63

4.085.305.203.804.00

5.083.624.825.31

FeO

2.512.352.482.262.28

2.211.702.772.002.46

3.171.902.021.981.75

2.332.881.881.90

MnO

0.290.870.190.240.14

0.190.690.230.250.54

0.220.280.230.360.170.140.160.210.36

MgO

2.863.982.893.152.87

2.822.432.542.823.41

2.952.762.932.272.34

2.632.352.893.25

CaO

0.640.390.740.130.64

0.230.782.790.700.35

1.131.871.752.321.96

2.214.101.931.93

Na2O

2.152.361.451.801.74

1.552.792.101.572.14

1.941.752.123.121.99

1.292.182.141.87

K 2 O

3.263.593.483.733.38

3.583.332.673.613.48

3.453.193.243.003.25

3.152.373.013.35

P2O5

0.160.150.160.140.16

0.140.170.140.150.170.180.170.150.140.130.180.160.150.17

Fe 203/Fe0

1.561.941.761.802.06

2.353.111.632.611.88

1.292.802.581.922.29

2.181.262.562.79

Total Fe

6.707.177.116.577.24

7.647.187.617.437.37

7.607.417.456.005.94

7.686.826.927.42

Tiba, T., 1974. Chemical composition of the deep sea corefrom the Philippine Sea. Bull. Nat. Sci. Museum, 17,181-185.

Watts, A. B., and Weissel, J. K., 1975. Tectonic history of theShikoku marginal basin. Earth Planet. Sci. Lett., 25,239-250.

730


TABLE 10Chemical Composition (%) Recalculated by Excluding Carbonates, Residual Materials, Water, and Salts, Hole 444A

No.

12345

6789

10

1112131415

1617181920

2122232425

2627282930

3132333435

3637383940

4142434445

4647484950

5152535455

SiO2

62.8063.0762.7163.5464.06

63.2771.2065.5961.9961.83

61.5662.3662.5862.4261.99

61.5263.0962.2861.5062.13

63.2459.1059.6661.4859.99

59.8364.9371.9864.7773.32

63.8462.3260.7359.3160.80

61.8363.8368.6075.3862.83

62.2373.5266.2361.2269.13

66.5261.8263.1164.6267.18

68.0662.5460.8961.5464.88

Tiθ2

0.770.770.840.800.73

0.730.550.650.750.79

0.820.800.770.700.73

0.770.740.730.770.78

0.750.770.780.810.79

0.870.760.460.690.49

0.650.840.770.800.80

0.770.750.640.490.73

0.690.440.670.710.56

0.540.700.690.660.67

0.570.700.710.710.68

AI2O3

19.5017.9218.9518.7418.53

17.9914.5117.5117.9018.35

18.0318.6217.8618.5319.06

18.2918.4818.7218.4018.69

17.7716.7516.5416.5716.61

16.0215.7614.1216.7714.10

16.6417.5616.5316.5717.23

16.7616.8314.5412.5617.44

17.3913.2116.3317.3714.13

15.9815.7915.8015.5514.52

15.3015.7015.0215.7815.26

Fe 2 O 3

5.365.316.385.415.18

5.433.194.435.425.66

5.305.985.486.426.49

7.065.936.066.806.82

6.566.176.255.615.76

7.124.152.124.122.55

4.545.726.356.276.26

6.145.102.811.215.64

4.961.904.796.433.29

4.216.325.604.852.93

3.877.197.436.536.62

FeO

2.122.201.752.012.01

1.901.792.132.191.81

2.451.921.821.121.25

1.251.101.401.211.30

1.992.772.933.423.62

3.833.411.772.601.97

3.143.722.833.753.12

3.073.092.992.112.19

2.431.872.272.701.66

2.262.502.702.513.16

2.251.801.972.101.89

MnO

0.260.240.500.390.23

0.320.170.120.370.39

0.370.470.420.390.39

0.550.420.350.450.33

0.480.610.580.330.28

0.250.220.150.210.19

0.250.350.200.180.34

0.180.270.150.0860.23

0.280.130.170.110.17

0.110.230.230.230.22

0.370.431.290.620.73

MgO

3.242.842.673.012.89

2.681.522.552.793.22

3.193.333.013.182.86

3.132.842.933.343.29

2.893.813.953.413.57

3.612.471.582.391.59

2.793.733.523.643.21

3.293.172.130.693.05

3.011.192.683.651.91

3.134.143.443.192.19

2.514.425.734.872.65

CaO

0.652.630.151.091.62

2.382.392.152.962.77

3.101.322.632.122.08

2.091.652.332.291.86

3.674.844.473.494.95

5.314.102.834.110.96

3.850.754.766.194.34

3.712.653.812.803.13

4.382.862.923.573.98

2.173.923.933.883.43

1.712.020.362.550.29

Na2O

1.782.071.711.431.56

2.062.411.532.652.20

2.392.052.461.971.94

2.172.352.152.101.82

0.143.082.692.522.40

1.492.592.652.202.61

1.892.252.081.631.58

1.691.852.502.701.92

2.382.571.551.471.93

1.411.941.951.933.06

2.341.993.602.223.71

K2O

3.342.794.033.383.02

3.052.183.222.782.80

2.582.942.782.952.99

3.013.202.892.962.82

2.361.922.001.771.88

1.541.452.232.002.12

2.242.592.061.522.17

2.402.301.681.892.65

2.072.222.242.633.14

3.532.452.362.382.53

2.893.092.862.953.01

P2O5 ]

0.190.170.320.190.16

0.180.0970.130.200.19

0.210.200.190.200.21

0.160.200.170.190.15

0.160.170.150.590.15

0.140.150.110.150.10

0.160.160.160.140.14

0.140.170.140.0900.18

0.190.0910.140.130.11

0.130.180.200.200.13

0.120.120.130.130.27

Pe2θ3/Fi

2.522.413.652.692.58

2.851.782.072.473.13

2.173.113.025.715.20

5.675.404.345.605.24

3.292.232.141.641.59

1.861.221.201.591.29

1.441.542.241.672.01

2.001.650.940.572.57

2.041.012.112.381.98

1.862.532.081.930.93

1.724.003.783.113.51

2O Total Fe

7.727.758.327.657.42

7.545.176.807.857.67

8.028.117.507.677.88

8.457.157.618.158.27

8.789.249.519.419.78

11.377.944.107.004.75

8.039.869.50

10.449.73

9.568.536.143.558.07

7.653.987.329.435.13

6.739.098.607.646.43

6.379.199.628.878.72

731

R. SUGISAKI

TABLE 11Average Chemical Compositions (%) and Standard Deviations of Sediments from Leg 58 Sites and Other Areas

Numberof Samples

SiO2

Tiθ2A12O3

Total FeasFe->Ch

Δ j

MnOMgOCaONa2OK2OP2O5

Site 442

91

63.44 ± 3.270.74 ± 0.08

17.77 ±1.53

7.57 ± 1.20

0.65 ± 0.733.13 ±0.921.28 ±0.692.13 ± 1.043.32 ±0.380.18 ± 0.14

Site 443

114

64.07 ± 2.540.74 ± 0.07

17.57 ± 1.06

7.51 ± 1.20

0.50 ± 0.492.96 ± 0.521.40 ±1.782.07 ± 0.693.26 ± 0.440.18 ±0.23

Site 444

74

64.04 ± 3.220.73 ± 0.09

17.03 ± 1.52

7.68 ± 1.45

0.32 ± 0.202.97 ± 0.762.48 ± 1.422.10 ±0.542.74 ± 0.590.17 ± 0.06

NankaiTrough*

29

66.68 ± 1.990.72 ± 0.06

16.51 ± 0.64

6.01 ± 0.65

0.09 ± 0.062.29 ± 0.361.51 ± 0.933.29 ± 0.363.09 ± 0.410.14 ± 0.01

JapanTrenchb

82

68.84 ± 2.780.62 ± 0.07

13.60 ± 1.47

5.67 ± 0.92

0.07 ± 0.023.11 ±0.372.38 ± 1.193.77 ± 0.492.12 ±0.300.15 ±0.13

Yamato BankAreac

69

65.80 ± 3.840.73 ±0.11

16.54 ± 1.96

6.94 ± 1.54

0.48 ± 1.952.91 ± 0.711.04 ± 0.652.16 ± 0.753.47 ± 0.470.16 ± 0.075

NishitsugaruBasind

87

66.58 ± 2.020.67 ± 0.05

16.12 ±0.63

5.85 ± 0.45

0.07 ± 0.043.31 ± 0.421.93 ± 0.903.00 ± 0.542.49 ± 0.280.17 ±0.15

Around theOki Islandse

45

75.59 ±2.570.50 ± 0.082

12.81 ± 1.39

4.03 ± 0.81

0.044 ± 0.0131.16 ±0.341.57 ±0.531.28 ±0.182.99 ± 0.25

0.097 ± 0.021

SouthPhilippine

Seaf

15

54.78 ± 0.591.05 ±0.10

21.54 ±0.86

11.45 ±1.34

0.68 ± 0.273.45 ± 0.261.30 ±0.152.51 ± 0.452.93 ±0.160.37 ± 0.15

East PacificOcean Pelagic

SedimentsS

35

49.841.22

17.38

9.29

1.983.484.065.393.01

, Sugisaki (1978); this area comprises the continental shelf and slope of the Pacific Side of southwest Japan, the Nankai Trough, and the northern Shikoku Basin.Sugisaki and Honza (in press).

^Sugisaki (in press b).Sugisaki (in press a).

^Sugisaki and Kinoshita (in press).rTiba (1974); core at Lat. 14°09 'N, Long. 130°04 'E.gGoldberg and Arrhenius (1958).

732


Site 442

SiO

MnO

Site 443

Total Fe(°/o)

MnO 2

C/β) !

0

SiO 2

6 β

60

r T TABLE 12Chemical Compositions (%) of Manganese-Rich Sediments

(silicate composition excluding carbonate, water, etc.)

Site 444

SiO2

TiO2

A12O3

Total FeasFe 2 θ3

MnOMgOCaONa2OK 2 O

P2O5

Lithologic Unit V, Site 442a

56.83 ± 3.180.56 ±0.083

13.67 ± 2.42

12.21 ± 3.262.67 ± 1.305.15 ± 1.141.33 ± 0.184.48 ± 1.502.91 ± 0.350.20 ± 0.04

Red Shaleb

60.380.73

17.13

12.651.181.010.551.954.820.18

Average of four sediment samples within 3 meters ofbasalt basement.Red shale above pillow basalt body in the Shimanto Beltin Kyushu, Cretaceous geosynclinal area, southwestJapan; Sugisaki et al. (1979) describe the chemical com-position of the basalt.

Total Fe 1 0

MnO

0.2

0 5 10 15

Age (m.y.)

Figure 1. Temporal variation of SiO2, total Fe as Fe2O3,and MnO at the Shikoku Basin sites. Each point rep-resents an average value for each lithologic unit ofthe cored sediments (see respective site chapters, thisvolume). The error bar shows standard deviation.

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R. SUGISAKI

Site Site UU2

AI2O3

Figure 2. Relationships among SiO2, TiO2 and A12O3.Closed circles represent argillaceous sediments ana-lyzed. Open circles represent averaged rocks: G, Jap-anese granites (Geological Survey of Japan, 1960); V,Quaternary volcanics (Sugisaki, 1976); C, shalesfrom the Paleozoic Chichibu terrain, Japan (Ono,1976); S, shales from the Mesozoic Shimanto terrain,Japan (Ono, 1976); I, Quaternary volcanics from theIzu-Mariana Islands (Sugisaki, 1976); Ph, averagesediments in a core from the Philippine Sea (Lat.14°09"N, Long. 130°04"E; Tiba, 1974); Pa, sedimentsfrom the east Pacific Ocean (Goldberg and Arrhenius,1958).

30

MgO

Figure 3. Relationships among TiO2, total Fe as Fe2O3,and MgO. Crosses and Xs represent averaged varia-tion trends of Japanese volcanics (Sugisaki, 1976)and Japanese granites (Aramaki et al., 1972), respec-tively. Other symbols are the same as those in Figure2.

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15

10

Site 442

FeO (7.)

Figure 4. Relation between FeO and Fe2O3 at Site 442.The regression line is Fe2O3 = -2.93FeO + 10.62,with a correlation coefficient of —0.832.

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Documents

23. MAJOR-ELEMENT CHEMISTRY OF ARGILLACEOUS …23. MAJOR-ELEMENT CHEMISTRY OF ARGILLACEOUS SEDIMENTS AT DEEP SEA DRILLING PROJECT SITES 442, 443, AND 444, SHIKOKU BASIN Ryuichi Sugisaki,