Citation:

29279

Name: (Table 1) U and Th isotope analyses of pyrite and anhydrite of ODP Site 158-957
Published: 1998
License: https://creativecommons.org/licenses/by/3.0/

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Abstract:

Hydrothermal circulation at oceanic spreading ridges causes sea water to penetrate to depths of 2 to 3 km in the oceanic crust where it is heated to ~400 °C before venting at spectacular 'black smokers'. These hydrothermal systems exert a strong influence on ocean chemistry (Edmond et al., 1979, doi:10.1016/0012-821X(79)90061-X), yet their structure, longevity and magnitude remain largely unresolved (Elderfield and Schultz., 1996, doi:10.1146/annurev.earth.24.1.191). The active Transatlantic Geotraverse (TAG) deposit, at 26° N on the Mid-Atlantic Ridge, is one of the largest, oldest and most intensively studied of the massive sulphide mounds that accumulate beneath black-smoker fields. Here we report ages of sulphides and anhydrites from the recently drilled (Humphris et al., 1995, doi:10.1038/377713a0) TAG substrate structures -determined from 234U-230Th systematics analysed by thermal ionization mass spectrometry. The new precise ages combined with existing data (Lalou et al., 1993, doi:10.1029/92JB01898; 1998, doi:10.2973/odp.proc.sr.158.214.1998) show that the oldest material (11,000 to 37,000 years old) forms a layer across the centre of the deposit with younger material (2,300–7,800 years old) both above and below. This stratigraphy confirms that much of the sulphide and anhydrite are precipitated within the mound by mixing of entrained sea water with hydrothermal fluid (James and Elderfield, 1996, doi:10.1130/0091-7613(1996)024<1147:COOFFA>2.3.CO;2). The age distribution is consistent with episodic activity of the hydrothermal system recurring at intervals of up to 2,000 years.

Project(s):

Ocean Drilling Program (ODP)

Coverage:

Median Latitude: 26.137029 * Median Longitude: -44.826100 * South-bound Latitude: 26.136600 * West-bound Longitude: -44.826400 * North-bound Latitude: 26.137200 * East-bound Longitude: -44.825800

Date/Time Start: 1994-10-10T10:00:00 * Date/Time End: 1994-11-10T10:30:00

Minimum Elevation: -3655.0 m * Maximum Elevation: -3548.0 m

Event(s):

158-957C * Latitude: 26.137200 * Longitude: -44.825800 * Date/Time Start: 1994-10-10T10:00:00 * Date/Time End: 1994-10-14T12:45:00 * Elevation: -3548.0 m * Penetration: 49.2 m * Recovery: 21.69 m * Location: South Atlantic Ocean * Campaign: * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 13 cores; 49.2 m cored; 0 m drilled; 44.1 % recovery

158-957E * Latitude: 26.137000 * Longitude: -44.826100 * Date/Time Start: 1994-10-15T22:30:00 * Date/Time End: 1994-10-27T21:45:00 * Elevation: -3646.0 m * Penetration: 125.7 m * Recovery: 4.03 m * Location: South Atlantic Ocean * Campaign: * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 18 cores; 94.2 m cored; 0 m drilled; 4.3 % recovery

158-957G * Latitude: 26.137000 * Longitude: -44.825800 * Date/Time Start: 1994-10-21T07:00:00 * Date/Time End: 1994-10-22T07:00:00 * Elevation: -3646.0 m * Penetration: 25 m * Recovery: 1.12 m * Location: South Atlantic Ocean * Campaign: * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 3 cores; 13 m cored; 0 m drilled; 8.6 % recovery

Parameter(s):

#	Name	Short Name	Unit	Principal Investigator	Method/Device	Comment
1	Event label	Event
2	Sample code/label	Sample label		You, Chen-Feng	DSDP/ODP/IODP sample designation
3	Mineral name	Mineral		You, Chen-Feng
4	Uranium	U	mg/kg	You, Chen-Feng	Thermal Ionization Mass Spectrometry (TIMS)
5	Uranium, error, relative	U e rel	%	You, Chen-Feng	Thermal Ionization Mass Spectrometry (TIMS)
6	Thorium	Th	mg/kg	You, Chen-Feng	Thermal Ionization Mass Spectrometry (TIMS)
7	Thorium, error, relative	Th e rel	%	You, Chen-Feng	Thermal Ionization Mass Spectrometry (TIMS)
8	Uranium-234/Uranium-238 activity ratio	(234U/238U)		You, Chen-Feng	Thermal Ionization Mass Spectrometry (TIMS)
9	Uranium-234/Uranium-238 activity ratio, error, relative	(234U/238U) e rel	%	You, Chen-Feng	Thermal Ionization Mass Spectrometry (TIMS)
10	Uranium-234/Uranium-238 activity ratio	(234U/238U)		You, Chen-Feng	Thermal Ionization Mass Spectrometry (TIMS)	initial
11	Thorium-230/Uranium-238 ratio	230Th/238U		You, Chen-Feng	Thermal Ionization Mass Spectrometry (TIMS)	atomic
12	Thorium-230/Uranium-238, error, relative	230Th/238U e rel	%	You, Chen-Feng	Thermal Ionization Mass Spectrometry (TIMS)
13	Thorium-230/Uranium-238 activity ratio	(230Th/238U)		You, Chen-Feng	Thermal Ionization Mass Spectrometry (TIMS)
14	Thorium-230/Uranium-238 activity ratio, error, relative	(230Th/238U) e rel	%	You, Chen-Feng	Thermal Ionization Mass Spectrometry (TIMS)
15	Age, dated	Age dated	ka	You, Chen-Feng	Age, 234U/230Th Uranium-Thorium
16	Age, dated standard deviation	Age dated std dev	±	You, Chen-Feng	Age, 234U/230Th Uranium-Thorium

License:

Creative Commons Attribution 3.0 Unported (CC-BY-3.0)

Size:

359 data points

Data

Download dataset as tab-delimited text — use the following character encoding:

1 Event	2 Sample label (DSDP/ODP/IODP sample designation)	3 Mineral	4 U [mg/kg] (Thermal Ionization Mass Spect...)	5 U e rel [%] (Thermal Ionization Mass Spect...)	6 Th [mg/kg] (Thermal Ionization Mass Spect...)	7 Th e rel [%] (Thermal Ionization Mass Spect...)	8 (234U/238U) (Thermal Ionization Mass Spect...)	9 (234U/238U) e rel [%] (Thermal Ionization Mass Spect...)	10 (234U/238U) (initial, Thermal Ionization M...)	11 230Th/238U (atomic, Thermal Ionization Ma...)	12 230Th/238U e rel [%] (Thermal Ionization Mass Spect...)	13 (230Th/238U) (Thermal Ionization Mass Spect...)	14 (230Th/238U) e rel [%] (Thermal Ionization Mass Spect...)	15 Age dated [ka] (Age, 234U/230Th Uranium-Thorium)	16 Age dated std dev [±] (Age, 234U/230Th Uranium-Thorium)
158-957C	158-957C-12N-1,40-42	anhydrite	227	0.10	0.879	0.55	1.281	6.11	1.290	0.000516	5.75	0.1184	6.02	10.507	0.920
158-957C	158-957C-12N-1,40-42	pyrite	1997	0.23	0.276	1.63	1.144	1.13	1.146	0.004418	5.10	0.0372	3.96	3.592	0.150
158-957C	158-957C-14N-1,9-10	anhydrite	2893	0.12	1.784	0.48	1.130	1.32	1.134	0.002691	1.69	0.1031	1.46	10.385	0.214
158-957C	158-957C-14N-1,9-10	pyrite	1069	0.14	0.076	0.26	1.126	0.40	1.128	0.018037	0.60	0.0774	0.40	7.736	0.045
158-957C	158-957C-14N-1,68-70	anhydrite	776	0.14	1.508	0.80	1.132	4.82	1.134	0.000332	5.19	0.0406	5.77	3.972	0.299
158-957C	158-957C-14N-1,68-70	pyrite	4716	0.11	0.102	0.58	1.135	0.25	1.137	0.028673	3.30	0.0378	3.54	3.679	0.132
158-957E	158-957E-5R-1,34-36	pyrite	1751	0.19	0.496	0.41	1.160	0.50	1.167	0.008584	0.64	0.1477	0.74	14.767	0.142
158-957E	158-957E-8R-1,16-20	pyrite	2758	0.08	1.650	0.33	1.135	0.19	1.137	0.001485	3.85	0.0540	3.05	5.294	0.165
158-957E	158-957E-15R-1,12-14	pyrite	7368	0.39	0.575	1.53	1.137	0.42	1.139	0.011688	1.82	0.0548	1.03	5.369	0.061
158-957G	158-957G-3N-1,44-47	pyrite	6258	0.60	0.539	0.27	1.139	0.45	1.140	0.006364	0.35	0.0334	0.67	3.231	0.027
158-957G	158-957G-3N-1,44-47	pyrite	6280	1.11	0.380	0.27	1.151	1.55	1.152	0.007772	0.76	0.0287	1.25	2.746	0.055
158-957G	158-957G-3-N1-44-47c	pyrite	8780	0.16	1.881	0.34	1.150	0.11	1.152	0.002257	0.46	0.0294	0.36	2.817	0.010
158-957G	158-957G-3N-1,44-47d	anhydrite	414	0.25	4.947	0.28	1.136	2.03	1.137	0.000031	0.80	0.0288	8.61	2.797	0.251
158-957G	158-957G-3N-1,44-47e	pyrite	6450	0.47	0.594	0.73	1.146	0.40	1.147	0.004803	0.16	0.0274	2.18	2.633	0.059
158-957G	158-957G-3N-1,44-47	pyrite	6310	0.62	0.471	0.68	1.164	0.71	1.166	0.007936	0.82	0.0326	1.63	3.086	0.056
158-957H	158-957H-5N-1,44-51	pyrite	2022	0.13	0.693	0.25	1.135	0.44	1.139	0.005126	0.69	0.1073	0.57	10.789	0.083
158-957H	158-957H-5N-1,0-3	pyrite	303	0.18	0.241	0.33	1.149	0.82	1.167	0.005398	0.46	0.3423	2.60	38.150	1.246
158-957H	158-957H-5N-1,0-3	pyrite	313	0.28	0.352	1.55	1.195	1.03	1.216	0.004939	2.89	0.3386	2.22	35.895	1.040
158-957H	158-957H-8N-1,90-92	pyrite	7765	1.07	1.215	0.78	1.137	0.80	1.140	0.007183	0.44	0.0686	1.23	6.761	0.102
158-957I	158-957I-1N-1,6-8	pyrite	2892	1.64	0.342	1.26	1.272	2.44	1.278	0.011805	3.11	0.0843	2.80	7.439	0.283
158-957K	158-957K-1X-1,30-33	pyrite	8934	0.29	0.413	2.58	1.141	0.58	1.144	0.020788	2.67	0.0576	1.95	5.629	0.118
158-957M	158-957M-2R-1,15-17	pyrite	4155	0.21	0.331	0.42	1.140	0.46	1.143	0.015514	0.44	0.0745	0.40	7.344
158-957M	158-957M-3R-1,60-64	pyrite	5360	0.10	1.151	0.10	1.140	0.49	1.144	0.008935	0.11	0.1166	0.16	11.722	0.064
158-957M	158-957M-8R-1,8-10	pyrite	22535	0.51	1.197	0.50	1.154	0.23	1.156	0.013547	0.42	0.0433	0.76	4.150	0.003