30. data report: chemical and isotopic compositions … · data report persed, platy-to-prismatic...

Carson, B., Westbrook, G.K., Musgrave, R.J., and Suess, E. (Eds.), 1995Proceedings of the Ocean Drilling Program, Scientific Results, Vol. 146 (Pt. 1)

30. DATA REPORT: CHEMICAL AND ISOTOPIC COMPOSITIONS OF PORE FLUIDSIN SEDIMENTS OF THE CASCADIA ACCRETIONARY COMPLEX1

Miriam Kastner2 and Henry Elderfield3

ABSTRACT

To complement the shipboard pore fluid chemical data from the Cascadia accretionary complex, Sites 888 to 892, thechemical and isotopic data reported here were carried out in our shore-based laboratories. The data include: (1) lithium andstrontium concentrations and strontium and oxygen isotope ratios for all sites drilled, both off Vancouver Island and off centralOregon; (2) calcium, magnesium, potassium, and sodium concentrations for Hole 892D pore fluid samples; and (3) strontiumand oxygen isotope ratios of a pure massive gas hydrate sample from Hole 892D. Shipboard Cl concentrations are included forbetter sample identification. The data reflect fluid-rock reactions and, at least at Site 892, advection of fluid from deeper in theaccretionary complex.

INTRODUCTION

The existence of large-scale fluid flow and fluid expulsion at con-vergent margins is demonstrated by (1) tectonically induced rapid po-rosity reduction of accretionary complexes; (2) regionally variableheat flow; (3) pore-fluid chemical, isotopic, and temperature anoma-lies that can only be maintained by rapid fluid flow; and (4) wide-spread diffuse and/or channelized fluid venting through mudvolcanoes or along thrusts. These fluids sustain prolific benthic bio-logical communities and cause carbonate deposition, primarily frommethane oxidation. High pore fluid pressures are pervasive in con-vergent margins. These fluids play a central role in the deformational,thermal, and chemical evolution of convergent margins, and enhancediagenetic and metamorphic reactions. Fluids released from these re-actions may be important for global geochemical budgets; H2O andCO2 may expedite partial melting at greater depths.

The expelled fluids are characterized by variable chemical andisotopic compositions. Fresher-than-seawater fluids are ubiquitous inaccretionary complexes; seawater dilutions of 10%-64% have beenrecorded. In the Cascadia accretionary complex a maximum seawaterdilution of 37% was observed at Site 889, and a 22% seawater dilu-tion was recorded in Hole 892D. Mostly gas hydrate dissociationcontributes to the observed Cl dilution at both sites.

Deciphering the origin(s) of the geochemically complex pore flu-ids in sediments of accretionary complexes requires an array ofchemical and isotopic data. Accordingly, the geochemical and isoto-pic data reported here provide new insights into the origin and flowof fluids in the Cascadia accretionary complex.

MATERIALS AND METHODS

All pore fluids analyzed were obtained by routine shipboardsqueezing of whole-round sediment samples immediately after re-trieval. The sediments were squeezed in titanium squeezers at ambi-ent temperature and at pressures of 135-205 MPa (140-210 kg/cm2).

The pore fluid samples were analyzed on board ship for a range ofconstituents. The shore-based pore fluid analyses emphasized lithiumand strontium concentrations and strontium and oxygen isotope ra-tios, summarized in Tables 1 through 9. Because of some shipboardproblems with the atomic absorption spectrophotometer, all pore flu-id samples were analyzed for Li concentrations at the Scripps Institu-tion of Oceanography (SIO) laboratories, including the samples fromthe three holes (889A, 891A, and 891B) analyzed for Li on boardship. Pore fluids from Hole 892D were also analyzed for Ca, Mg, K,and Na concentrations using the shipboard methods described inGieskes et al. (1991). Lithium and strontium concentrations weremeasured by atomic absorption spectroscopy. The precision for Srwas <3.0% and for Li only 10% because of the low Li concentrations.Strontium and oxygen isotope ratios were determined by mass spec-trometry. For the pore fluid oxygen isotope analysis, the method ofBottinga and Craig (1969) was used with a precision of 0.08%o.Strontium isotopes were determined by the previously describedmethod (e.g., Elderfield and Gieskes, 1982). The 2σ errors are givenin Tables 6 through 9. Measured 87Sr/86Sr ratios were normalized to aparticular value (to 86Sr/88Sr = 0.1194) for a standard; the value ob-tained for the National Bureau of Standards (NBS) 987 standard mea-sured in the SIO laboratory is 0.710255, with a 2σ error of 18.

GENERAL RESULTS

The data indicate the uniqueness of Site 892 pore-fluid geochem-istry relative to the other drilled sites on Leg 146 at the Cascadia ac-cretionary complex. At Site 892, the Li and Sr concentrations are twoto three times higher (Figs. 1,2) and the 87Sr/86Sr significantly less ra-diogenic (Fig. 3). The pore-fluid Sr isotope data of all sites are lessradiogenic than modern or contemporary seawater Sr isotopic values(e.g., Burke et al., 1982; see Tables 6-9 and Fig. 3). The slightly neg-ative oxygen isotope values in Tables 6-9 and Figure 4 reflect in-situlow-temperature formation of diagenetic minerals of either carbon-ates and/or silicates.

'Carson, B., Westbrook, G.K., Musgrave, R.J., and Suess, E. (Eds.), 1995. Proc.ODP, Sci. Results, 146 (Pt. 1): College Station, TX (Ocean Drilling Program).

2Scripps Institution of Oceanography, La Jolla, CA 92093-0212, U.S.A.3 Department of Earth Sciences, University of Cambridge, Cambridge CB2 3EQ,

United Kingdom.

GAS HYDRATE

Gas hydrate was recovered between 2 and 5 and -19 mbsf inHoles 892A, 892D, and 892E. Most of it occurs as individual, dis-

431

DATA REPORT

persed, platy-to-prismatic 1- to 1.5-cm-long white crystals or in crys-tal clusters. Only one 2- to 3-cm-thick massive gas hydrate layer wasobtained in Core 146-892D-3X; it was immediately frozen in liquidnitrogen. This is a CH4-H2S gas hydrate, with -10% H2S; it also con-tains minor amounts of ethane and CO2. The δ13C value of the meth-ane is -67.5 (%o, PDB), suggesting a biogenic or possibly a mixedbiogenic-thermogenic source. This is remarkably similar to the δ'3Cvalue of methane reported by Suess and Whiticar (1989) from the Or-egon Cascadia margin, suggesting a similar or common source. Theδ 1 8 θ value of the H2O which includes -6% admixed seawater is+2.77(%o, SMOW); the δ 1 8 θ value of the pure hydrate H2O, assuming0%o for the seawater, is thus 2.9%c. This value is similar to the exper-imentally determined oxygen isotope fractionation factor of 1.0026in a gas hydrate-water system (Davidson et al., 1983) and basicallythe same as the experimentally determined oxygen isotope fraction-ation factor in the ice-water system (Craig and Hom, 1969; Suzukiand Kimura, 1973).

REFERENCES

Bottinga, Y., and Craig, H., 1969. Oxygen isotope fractionation between CO2

and water and the isotopic composition of marine atmospheric CO2.Earth Planet. Sci. Lett., 5:285-295.

Burke, W.H., Denison, R.E., Hetherington, E.A., Koepnick, R.B., Nelson,H.F., and Otto, J.B., 1982. Variation of seawater 87Sr/86Sr throughoutPhanerozoic time. Geology, 10:516-519.

Craig, H., and Hom, B., 1969. Relationship between deuterium, oxygen-18and chlorinity in the formation of sea ice. Trans. Am. Geophys. Union,49:216-217.

Davidson, D.W., Leaist, D.G., and Hesse, R., 1983. Oxygen-18 enrichmentin water of a clathrate hydrate. Geochim. Cosmochim. Acta., 47:2293-2295.

Elderfield, H., and Gieskes, J.M., 1982. Sr isotopes in interstitial waters ofmarine sediments from Deep Sea Drilling Project cores. Nature, 300:493-497.

Gieskes, J.M., Gamo, T., and Brumsack, H., 1991. Chemical methods forinterstitial water analysis aboard JOIDES Resolution. ODP Tech. Note,15.

Suess, E., and Whiticar, MJ., 1989. Methane-derived CO2 in pore fluidsexpelled from the Oregon subduction zone. Palaeogeogr., Palaeoclima-tol, Palaeoecol, 71:119-136.

Suzuki, T., and Kimura, T., 1973. D/H and 18O/16O fractionation in ice-watersystems. Mass Spectros. (Tokyo), 21:229-233.

Date of initial receipt: 23 August 1994Date of acceptance: 28 February 1995Ms 146SR-211

Table 1. Chemical composition of pore fluid samples from Site 888.

Core, section,interval (cm)

146-888B-1H-2, 143-1501H-3, 105-1102H-2, 145-1502H-3, 53-583H-2, 145-1504H-4, 145-1505H-4, 143-1506H-5, 140-1507H-3, 140-1508H-4, 140-1509H-3, 140-15010H-4, 140-15011H-3, 142-15212H-2, 139-14914H-4, 140-15015H-4, 138-15016H-5, 138-15017H-4, 140-15018X-2, 135-15019X-5, 1-1524H-1, 135-15025H-3, 135-15026H-3, 135-15027H-5, 140-15030H-4, 130-15031H-5, 130-15034H-1, 130-15036H-2, 70-8040H-5, 130-15044X-4, 1-1545X-1, 135-15048X-CC,53X-CC, 3-1854X-1, 130-15057X-1, 130-15058X-3, 1-2059P-1, 2-1460X-1, 30-4061X-1, 1-1062X-2, 130-15063X-2, 130-15064X-1, 130-15065X-5, 1-25

Depth(mbsf)

2.94.08.59.1

18.030.439.950.957.468.476.487.495.3

103.4124.0133.5144.5152.5159.0171.6214.3221.8231.3241.6266.6275.1293.7312.2355.3389.5396.4423.5460.5470.7497.5508.1514.0515.3522.8534.5543.2550.5564.1

Cl(mM)

545546552551562561564565568571559560559558556554554553545543552552550546547554548550552556559563563563556551545563556564562562562

Ca/Cl(I0"2)

1.881.892.082.122.162.202.272.081.841.711.651.691.501.311.841.961.731.491.401.551.231.221.171.091.051.021.191.031.171.441.441.231.621.712.192.422.472.392.242.662.903.072.83

Li(µM)

23.730.611.323.723.710.016.810.013.423.722.520.310.023.719.924.816.810.016.810.016.829.420.319.719.927.223.730.630.630.632.023.727.561.544.3

51.5

55.046.437.9

32.3

Li/Cl(I0-4)

0.430.560.200.430.420.180.300.180.240.420.400.360.180.420.360.450.300.180.310.180.300.530.370.360.360.490.430.560.550.550.570.420.491.090.80

0.94

0.990.820.67

0.57

Sr(µM)

91.0

101.685.281.191.498.496.092.148.448.456.693.497.5

105.585.291.475.0

105.783.2

101.6123.7112.2114.0109.1108.1107.8107.8103.5128.3122.1116.0120.4105.7116.0107.8113.9

105.7121.5120.1111.9126.2

Sr/Cl(io-4)

1.67

1.841.551.441.631.741.701.620.850.871.011.671.751.901.541.651.361.941.531.842.242.042.091.991.951.971.961.882.312.182.062.141.882.091.962.09

1.902.152.141.992.25

DATA REPORT

Table 2. Chemical composition of pore fluid samples from Sites 889 and 890.


146-890B-1H-2, 145-1501H-3, 145-1502H-2, 63-682H-3, 53-582H-6, 145-1503H-2, 143-1503H-5, 150-1555H-5, 0-10

146-889A-1H-2, 1-61H-4, 145-1502H-5, 145-1503H-5, 1-64H-5, 143-1505H-3, 143-1506H-5, 145-1507H-2, 143-1508H-3, 140-1509H-6, 137-15010H-4, 140-15011H-1, 140-15011H-2, 130-15012H-4, 140-15013H-CC, 0-514H-1, 153-15815P-1, 6-1317X-2, 70-8018X-4, 36-4622X-7, 0-2024X-5, 120-14025X-2, 0-2026X-4, 130-15028X-4, 80-10030X-4, 130-15031X-5, 140-16032X-1, 130-15036X-1,99-11440X-4, 45-6541X-3, 130-15043X-2, 0-544X-1, 0-15

146-889B-3R-1,79-944R-2, 45-605R-1, 26-366R-1, 54-697R-1, 103-1268R-2, 130-1509R-1, 130-15010R-2, 0-2012R-1, 130-15013R-2, 35-5514R-1, 111-13615R-1, 125-15017R-1.0-1518R-l,0-1020R-CC, 0-3

Depth(mbsf)

3.04.59.4

10.816.519.724.243.9

21.626.035.545.056.062.575.0

91.0103.4109.9115.0116.4125.0128.0128.5129.1132.4144.5179.8195.1198.8212.7222.6233.7244.0248.0267.7306.6316.4329.9337.3

216.5227.3235.1244.9255.0265.6274.3282.0299.6309.1317.0326.0342.2351.1377.6

Cl(mM)

544541

526522515508473

528521499488462456442432424412405401

398391378363379388378366364370372358352360364365362367376

368380370

372370371364365375368379369366

Ca/Cl(I0-2)

1.270.940.620.630.420.300.370.30

0.660.570.610.590.440.270.500.610.730.880.950.99

0.991.041.071.210.960.871.061.191.071.131.111.131.071.141.171.201.391.561.49

0.981.171.201.171.161.151.121.291.211.301.351.501.561.411.74

Li(µM)

26.221.728.628.627.921.724.432.1

19.822.722.722.722.722.726.631.531.531.535.840.240.241.044.650.0

49.049.057.962.466.566.566.570.078.871.7

107.9108.4

79.984.084.790.684.099.2

110.3105.9

127.8

106.0195.2

Li/Cl(I0"4)

0.480.400.540.540.530.420.480.68

0.380.440.450.470.490.500.600.730.740.760.881.00

1.031.141.32

1.261.301.581.711.801.791.861.992.191.972.962.99

2.102.272.322.502.262.68

3.032.90

3.47

2.875.33

Sr(µM)

76.169.064.361.458.053.952.351.7

74.771.866.559.852.052.054.456.756.754.452.052.038.452.052.050.138.1

50.446.361.552.759.256.749.753.256.158.760.560.862.6

63.352.558.759.854.5

56.659.1

66.862.770.960.777.6

Sr/Cl(1(H)

1.401.281.211.171.111.051.031.09

1.411.381.331.231.131.141.231.311.341.321.281.30

1.311.331.331.05

1.301.221.681.451.601.521.391.511.561.611.661.681.71

1.671.421.611.651.47

1.531.62

1.781.701.871.642.12

433

DATA REPORT

Table 3. Chemical composition of pore fluid samples from Site 891.


146-891A-1H-1, 140-1501H-3, 103-1132H-1, 109-1193H-2, 53-68

146-891B-3X-CC4X-CC, 0-58X-1, 15-2011X-2, 16-2114X-1,54-6415X-1,82-9016X-1,57-6718X-CC, 26-3719X-l,0-1020X-1, 28-3821N-CC, 0-522X-1,55-6723X-1,50-6025X-CC, 13-2026X-1,42^627X-1, 15-2528X-1,32-5029X-1,22-2930X-1,75-8331X-32X-33X-34X-35X-36P-138X-:39X-40X-41X-41X-

, 135-150, 11-17,0-17,100-115, 16-28,0-6',0-18, 101-118,0-11, 110-135135-150

42X-l,0-1843X-1, 10-2745X-1,6-1447X-1.95-11048X-1.0-1549X-1,23-2950X-1, 17-2052X-1,7-2155X-2, 130-15056X-1,72-8958X-2, 15-27

Depth(mbsf)

2.94.0

9.3

20.829.665.492.3

110.0119.2127.9148.4153.9163.0172.1176.7181.1198.9207.5216.1225.0233.8238.4243.8251.5260.2264.1269.2277.8287.9296.1304.0314.1314.2321.6330.5348.3367.1375.0384.1393.0410.6439.0446.5464.6

Cl(mM)

545527546551

532533537540540545545546541545546546545555554561557556557562561561563558557555552557556553560562554559561550555553546546557

Ca/Cl(I0-2)

1.051.170.921.01

1.721.691.811.851.831.721.601.801.801.811.741.621.541.01

0.900.920.960.990.970.991.140.900.911.021.031.011.021.321.472.041.12

1.201.09

1.681.721.061.10

Li(µM)

26.221.721.721.7

38.4

23.126.623.234.230.618.921.715.9

21.7

10.0

27.314.33.1

18.221.725.136.510.0

28.640.750.439.153.852.119.618.218.248.1

31.550.244.534.5

Li/Cl(io-4)

0.480.410.400.39

0.72

0.430.490.430.630.560.350.400.29

0.40

0.18

0.490.260.060.330.390.450.650.18

0.510.730.910.700.970.940.350.320.330.86

0.570.920.810.62

Sr(µM)

93.495.587.2

108.7

89.393.493.489.395.590.797.5

105.7102.3112.5105.797.5

89.397.5

107.4101.6103.7101.695.5

108.6

99.6

108.6103.7103.7110.3116.0103.6109.8

137.5126.2114.2128.3140.9123.7116.0116.4

Sr/Cl(I0"4)

1.711.811.601.97

1.681.751.741.651.771.661.791.941.892.061.941.79

1.611.761.911.821.861.831.70

1.94

1.79

1.961.881.861.982.101.851.95

2.462.252.082.312.552.272.122.09

Table 4. Chemical composition of pore fluid samples from Hole 892A.


146-892 A-1X-5, 10-132X-3, 0-113X-2, 0-103X-3, 0-104X-2, 0-106X-2, 0-106X-2, 10-307X-5, 140-1508X-3, 0-109X-1,69-7411X-2, 0-1011X-2, 70-9512X-1.0-713X-4, 0-2513X-6, 69-8214X-1, 35-3815X-1, 88-10016X-1, 34^317X-2, 3-1318X-1, 115-14018X-1, 140-15020X-2, 0-1020X-3, 0-10

Depth(mbsf)

6.112.620.622.130.140.640.755.961.0

79.680.387.5

101.6105.3106.9116.9125.8136.6145.8146.0165.1166.5

Cl(mM)

483468557552523544545507534480517516489504501491497493481487487

496

Ca/Cl(I0"2)

0.700.901.000.801.001.001.101.201.201.301.301.401.501.401.401.601.401.401.401.401.401.401.40

Li(µM)

28.428.766.771.684.3

110.3116.4143.4155.8

176.3186.8

188.4161.6215.3168.5168.3156.3167.9161.0156.9154.0

Li/Cl

0.590.611.201.301.612.032.142.832.92

3.413.62

3.743.234.383.393.413.253.453.313.213.11

Sr(µM)

70.775.4

164.3159.6169.0192.4199.4208.7229.8232.7267.2262.5245.0259.4213.2234.8223.7260.2207.5264.9260.2278.9261.4

Sr/Cl(l<T4)

1.461.612.952.893.233.543.664.124.304.855.175.095.025 . 1 54.264.784.505.284.315.445.345.705.27

434

DATA REPORT

Table 5. Chemical composition of pore fluid samples from Hole 892D.


146-892D-1X-1,9-122X-1, 145-1502X-2, 140-1503X-1,40-454X-2.4-114X-2, 21-304X-3, 80-885X-2, 140-1506X-4, 140-1507X-3, 142-1508X-3, 0-109X-4, 0-1510X-4,0-1511X1, 130-15012X-3, 130-15013X-CC, 22-2414X-1, 115-13015X-2, 110-13515X-2, 135-15016X-3, 135-15016X-5, 135-150

Depth(mbsf)

0.110.011.418.429.029.230.839.952.458.264.773.8

104.5110.9123.4128.5139.2148.6148.9161.4164.4

Cl(mM)

547539447433575505570560550551541500496505488484490489492484485

Ca(mM)

9.683.372.903.26

5.07

5.565.913.664.104.64

4.674.20

3.944.814.003.563.78

Ca/Cl(I0"2)

1.800.600.700.80

1.00

1.001.100.700.800.90

0.900.90

0.801.000.800.700.80

Mg(mM)

49.4239.9330.7531.81

32.93

33.9732.5231.9228.9723.71

21.3121.48

21.5921.8521.4521.9621.43

K(mM)

13.1012.6210.6210.7010.8710.0110.8510.239.709.409.057.665.906.676.55

6.536.886.506.476.36

Na(mM)

474461388376

441

495479486481448

459445

447

451442444

Li(µM)

33.331.227.828.882.061.084.1

104.3126.7147.2154.7163.0175.2170.7165.2

156.8160.5147.7141.0136.4

Li/Cl(I0"4)

0.610.580.620.671.431.211.481.862.302.672.863.263.533.383.39

3.203.283.002.912.81

Sr(µM)

87.180.163.754.2

161.7131.3180.7197.0211.1234.5239.1250.8273.7277.0260.2272.9267.2246.2267.2267.2267.2

Sr/Cl(I0"1)

1.591.491.431.252.812.603.173.523.844.264.425.025.525.495.335.645.455.035.435.525.51

Table 6. Strontium concentration and strontium and oxygen isotope ratios of pore fluids, Site 888.


146-888B-2H-2, 140-1505H-4, 143-1508H-4, 140-15012H-2, 140-15015H-4, 138-15019X-5.0-1525H-3, 135-15034H-1, 130-15045X-1, 135-15053X-1.3-1859P-1,2-1461X-l,0-1064X-1, 130-150

Depth(mbsf)

8.539.968.4

103.4133.5171.6221.8293.7396.4460.5514.0522.8550.5

Sr(µM)

101.698.448.497.585.283.2

123.7107.8122.1120.4113.9105.7111.9

87 S r / 86 S r

0.7089040.7083640.7085240.7083400.7078250.7078310.7077790.7080590.7083800.7081590.7078130.7079410.707590

2σ

18182118231716152325161725

δ 1 8 o(‰SMOW)

0.040.300.20

-0.19-0.51-0.51-0.65-0.62-0.79-0.88-1.23-1.04-1.07

Table 7. Strontium concentration and strontium and oxygen isotope ratios of pore fluids, Sites 889 and 890.


146-890B-2H-2, 63-683H-5, 150-1555H-5, 0-10

146-889A-3H-5, 1-6889A-4H-5, 143-150889A-5H-3, 143-150889A-6H-5, 145-150889A-8H-3, 140-150889A-11H-1, 140-150889A-12H-4, 140-150889A-13H-CC, 0-5889A-15P-1,6-13889A-17X-2, 70-80889A-18X-4, 36-46889A-24X-5, 120-140889A-26X-4, 130-150889A-28X-4, 80-100889B-4R-2, 45-60889A-30X-4, 130-150889A-32X-1, 130-150889B-8R-2, 130-150889A-36X-1.99-114889B-9R-1, 130-150889A-40X-4, 45-65889A-43X-2, 0-5889B-18R-1.0-10889B-20R-CC, 0-3

Depth(mbsf)

9.424.243.9

45.056.062.575.091.0

115.0125.0128.0129.1132.4144.5195.1212.7222.6227.3233.7248.0265.6267.7274.3306.6329.9351.1377.6

Sr(µM)

64.352.351.7

59.852.052.054.456.752.052.052.038.1

50.461.559.256.763.349.756.154.558.7

60.562.660.777.6

87Sr/86Sr

0.7090020.7090180.708887

0.7089770.7088990.708826

0.7086370.7085210.708544

0.7086220.7085140.7084970.708507

0.7084920.7085540.7084380.7084020.708477

0.7084490.7082370.7082240.7082130.707766

2σ

171619

191618

201818

17151716

1618181619

1518161819

δ 1 8 o(‰SMOW)

-0.22-0.34

-0.63-0.77-1.07-1.19-1.37

-1.49

-1.44-1.32-1.44-1.30-1.38

-1.42

-1.43-1.40-1.53-1.38

435

DATA REPORT



146-891A-2H-1, 109-119

146-891B-4X-CC, 0-514X-1,54-6420X-1,28-3823X-1,50-6025X-CC, 13-2026X-1,42^627X-1, 15-2529X-1,22-2931X-1, 135-15033X-1.0-1734X-1, 100-11535X-1, 16-2838X-2, 0-1842X-1.0-1847X-1, 95-11050X-1, 17-2055X-2, 130-15056X-1,72-8958X-2, 15-27

Depth(mbsf)

5.8

29.6110.0163.0181.1198.9207.5216.1233.8243.8260.2264.1269.2287.9321.6367.1393.0439.0446.5464.6

Sr(µM)

87.2

93.495.5

112.5

89.397.5

107.4103.795.5

108.6

99.6108.6103.6137.5128.3123.7116.0116.4

87Sr/86Sr

0.708561

0.7090760.708993

0.7081440.7080790.708099

0.7081990.7082700.7083080.7083250.708349

0.7081350.7080370.7083000.7082070.7083160.708153

2σ

18

1817

253537

4118172017

181421312023

δ 1 8 θ(‰SMOW)

-0.12

-0.07-0.24-0.09

-0.08-0.16-0.25-0.56-0.58-0.50-0.69-0.52-0.69-0.73-0.51-0.77-1.17-1.28-0.69



146-892D-1X-1,9-12892D-1X-1, 145-150892D-2X-2, 140-150892A-2X-3, 0-11892A-3X-2, 0-10892A-4X-2, 0-10892A-6X-2, 0-10892D-6X-4, 140-150892A-7X-5, 140-150892A-8X-3, 0-10892D-8X-3, 0-10892 A-9X-1,69-74892D-9X-4, 0-15892A-11X-2.0-10892A-13X-4.0-25892A-15X-1, 88-100892D-12X-3, 130-150892 A-16X-1,34-^3892D-13X-CC, 22-24892A-17X-2, 3-13892D-14X-1, 115-130892A-18X-1, 115-140892D-15X-2, 135-150892D-16X-3, 135-150892D-16X-5, 135-150892A-20X-2, 0-10

Depth(mbsf)

0.110.011.412.620.630.140.652.455.961.064.768.273.879.6

101.6116.9123.4125.8128.5136.6139.2145.8148.9161.4164.4165.1

Sr(µM)

87.180.163.775.4

164.3169.0192.4211.1208.7229.8239.1232.7250.8267.2259.4223.7260.2260.2272.9207.5267.2264.9267.2267.2267.2278.9

87Sr/86Sr

0.7088780.7085600.7084110.7077180.7075890.7074610.7074610.7072770.7072890.7072680.7071680.7071370.7071160.7070950.7070940.7070430.7071150.7070760.707098

0.7071260.707088

0.7070690.707109

2σ

19182018181620182118181720181622181518

1521

1817

δ 1 8 o(%CSMOW)

-0.07-0.17

0.33-0.04-0.11-0.11-0.26

-0.30-0.33-0.49-0.32-0.31-0.48-0.52

-0.61-0.56-0.68-0.67-0.15-0.72-0.75

-0.82

436

DATA REPORT

0

100

200

-Q

E300

Q.

Q400

500

600

SW

- •- -888— • — 8 8 9 & 9 0-―A—-891- -O---892A

0 50 100 150 200 250

Li (µM)

Figure 1. Depth profiles of lithium concentrations in pore fluids from Sites888, 889/890, 891, and 892. The arrow indicates seawater (SW) concentra-tion.

0

100

200

-Q

E300 -

GL

Q

fi""'•̂ ^̂ -̂ Λ

I t"-

rr•

i

" -cob .

o

o -

—— • —

-•--Δ—

— o- - -i i

1 I

%

•—~~ " -co

\o •o

-

-

-

888889&90

891892A

400

500 -

600

0 50 100 150 200 250 300

Sr (µM)

Figure 2. Depth profiles of strontium concentrations in pore fluids from Sites

888, 889/890, 891, and 892. The arrow indicates seawater (SW) concentra-

tion.

437

DATA REPORT

SW SW

QLCDQ

100 -

200 -

300 -

400

500 -

600

0.7068 0.7076 0.7084 0.70928 7 Sr/ 8 6 Sr

Figure 3. Depth profiles of strontium isotope ratios in pore fluids from Sites888, 889/890, 891, and 892. The arrow indicates seawater (SW) concentra-tion. BSR = bottom-simulating reflector.

0

100

200 -

_Q

300 -

Q.

Q

400 -

500 -

600

- /""r

z* • -Δ

•

i

; / × À

A

•Δ•

-

- -888—•—889&90•--- - — 8 9 1- o -892

i

-1.6 -0.8 0.0

δ18O(°/ SMOW)

0.8

oo

Figure 4. Depth profiles of oxygen isotope ratios in pore fluids from Sites888, 889/890, 891, and 892. The arrow indicates seawater (SW) concentra-tion.

30. data report: chemical and isotopic compositions … · data report persed, platy-to-prismatic...

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