Citation:

S0025-3227(00)00026-8

Name: (Table 1) Results of pore water analyses, including boron content and boron isotope ratios
Published: 2000
License: https://creativecommons.org/licenses/by/3.0/

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Abstract:

Drilling a transect of holes across the Costa Rica forearc during ODP Leg 170 demonstrated the margin wedge to be of continental, non accretionary origin, which is intersected by permeable thrust faults. Pore waters from four drillholes, two of which penetrated the décollement zone and reached the underthrust lower plate sedimentary sequence of the Cocos Plate, were examined for boron contents and boron isotopic signatures. The combined results show dilution of the uppermost sedimentary cover of the forearc, with boron contents lower than half of the present-day seawater values. Pore fluid "refreshening" suggests that gas hydrate water has been mixed with the sediment interstitial water, without profoundly affecting the d11B values. Fault-related flux of a deeply generated fluid is inferred from high B concentration in the interval beneath the décollement, being released from the underthrust sequence with incipient burial.

First-order fluid budget calculations over a cross-section across the Costa Rica forearc indicate that no significant fluid transfer from the lower to the upper plate is inferred from boron fluid profiles, at least within the frontal 40 km studied. Expulsed lower plate pore water, which is estimated to be 0.26-0.44 km3 per km trench, is conducted efficiently along and just beneath the décollement zone, indicating effective shear-enhanced compaction. In the upper plate forearc wedge, dewatering occurs as diffuse transport as well as channelled flow. A volume of approximately 2 km3 per km trench is expulsed due to compaction and, to a lesser extent, lateral shortening. Pore water chemistry is influenced by gas hydrate instability, so that it remains unknown whether deep processes like mineral dehydration or hydrocarbon formation may play a considerable role towards the hinterland.

Project(s):

Integrated Ocean Drilling Program / International Ocean Discovery Program (IODP)

Coverage:

Median Latitude: 9.674986 * Median Longitude: -86.168114 * South-bound Latitude: 9.639700 * West-bound Longitude: -86.200000 * North-bound Latitude: 9.733700 * East-bound Longitude: -86.116300

Date/Time Start: 1996-11-02T03:30:00 * Date/Time End: 1996-12-11T05:45:00

Minimum DEPTH, sediment/rock: 1.45 m * Maximum DEPTH, sediment/rock: 652.75 m

Event(s):

170-1039B * Latitude: 9.640000 * Longitude: -86.200000 * Date/Time Start: 1996-11-02T03:30:00 * Date/Time End: 1996-11-05T00:00:00 * Elevation: -4353.5 m * Penetration: 384.3 m * Recovery: 382.46 m * Location: Costa Rica subduction complex, North Pacific Ocean * Campaign: * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 42 cores; 384.3 m cored; 0 m drilled; 99.5 % recovery

170-1039C * Latitude: 9.639700 * Longitude: -86.200000 * Date/Time Start: 1996-11-08T14:00:00 * Date/Time End: 1996-11-11T01:15:00 * Elevation: -4351.4 m * Penetration: 448.7 m * Recovery: 37.65 m * Location: Costa Rica subduction complex, North Pacific Ocean * Campaign: * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 11 core; 85.6 m cored; 0 m drilled; 44 % recovery

170-1040B * Latitude: 9.661700 * Longitude: -86.179100 * Date/Time Start: 1996-11-05T15:45:00 * Date/Time End: 1996-11-08T06:30:00 * Elevation: -4178.0 m * Penetration: 190.2 m * Recovery: 127.92 m * Location: Costa Rica subduction complex, North Pacific Ocean * Campaign: * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 22 cores; 190.2 m cored; 0 m drilled; 67.3 % recovery

Comment:

Depth, sediment = mbsf

Parameter(s):

#	Name	Short Name	Unit	Principal Investigator	Method/Device	Comment
1	Event label	Event
2	Sample code/label	Sample label		Kopf, Achim J	DSDP/ODP/IODP sample designation
3	DEPTH, sediment/rock	Depth sed	m			Geocode
4	Porosity	Poros	% vol	Kopf, Achim J
5	δ11B	δ11B	‰ SRM	Kopf, Achim J	Thermal Ionization Mass Spectrometry (TIMS)
6	δ11B	δ11B	‰ SRM	Kopf, Achim J	Thermal Ionization Mass Spectrometry (TIMS)	corrected
7	Boron	B	mmol/l	Kopf, Achim J	Inductively coupled plasma atomic emission spectroscope (ICP-AES)
8	Boron	B	mmol/l	Kopf, Achim J	Inductively coupled plasma atomic emission spectroscope (ICP-AES)	adsorbed
9	Boron	B	mmol/l	Kopf, Achim J	Inductively coupled plasma atomic emission spectroscope (ICP-AES)	corrected
10	Sodium	Na	mmol/l	Kopf, Achim J	Inductively coupled plasma atomic emission spectroscope (ICP-AES)
11	Strontium	Sr	µmol/l	Kopf, Achim J	Inductively coupled plasma atomic emission spectroscope (ICP-AES)
12	Lithium	Li	µmol/l	Kopf, Achim J	Inductively coupled plasma atomic emission spectroscope (ICP-AES)
13	pH	pH		Kopf, Achim J
14	Alkalinity, total	AT	mmol(eq)/l	Kopf, Achim J
15	Salinity	Sal		Kopf, Achim J
16	Chloride	Cl-	mmol/l	Kopf, Achim J
17	Boron/Chlorine ratio	B/Cl		Kopf, Achim J

License:

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

Size:

861 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 Depth sed [m]	4 Poros [% vol]	5 δ11B [‰ SRM] (Thermal Ionization Mass Spect...)	6 δ11B [‰ SRM] (corrected, Thermal Ionization...)	7 B [mmol/l] (Inductively coupled plasma at...)	8 B [mmol/l] (adsorbed, Inductively coupled...)	9 B [mmol/l] (corrected, Inductively couple...)	10 Na [mmol/l] (Inductively coupled plasma at...)	11 Sr [µmol/l] (Inductively coupled plasma at...)	12 Li [µmol/l] (Inductively coupled plasma at...)	13 pH	14 AT [mmol(eq)/l]	15 Sal	16 Cl- [mmol/l]	17 B/Cl
170-1039B	170-1039B-1H-1,145-150	1.45	79	35.4	35.1	0.615	2.154	0.551	0.463	89	21	7.77	6.5	3.45	555	1.110
170-1039B	170-1039B-2H-2,140-150	4.90	77	35.5	35.2	0.599	2.140	0.536	0.461	83	20	7.89	14.8	3.45	654	1.080
170-1039B	170-1039B-2H-5,140-150	9.40	75	35.0	34.6	0.585	2.147	0.524	0.452	89	18	7.74	18.6	3.45	552	1.060
170-1039B	170-1039B-4H-2,140-150	23.90	74	37.5	37.2	0.562	2.087	0.503	0.472	90	24	7.71	20.2	3.45	551	1.020
170-1039B	170-1039B-5H-4,140-150	36.40	79	39.2	38.8	0.539	2.001	0.477	0.496	103	25	7.89	18.8	3.41	551	0.970
170-1039B	170-1039B-7H-4,140-150	55.90	72	39.9	39.5	0.459	1.743	0.411	0.459	110	24	7.62	16.2	3.40	549	0.840
170-1039B	170-1039B-9H-4,140-150	74.43	71	40.9	40.4	0.480	1.851	0.385	0.470	120	24	7.68	14.1	3.40	652	0.780
170-1039B	170-1039B-12X-3,135-150	101.35	69	41.0	40.5	0.618	2.032	0.484	0.467	162	25	7.68	11.5	3.40	548	0.850
170-1039B	170-1039B-13X-6,136-150	112.35	67	40.7	40.3	0.460	1.803	0.403	0.472	169	24	7.68	9.5	3.40	548	0.820
170-1039B	170-1039B-17X-4,135-150	147.65	65	40.0	39.6	0.424	1.784	0.390	0.456	198	18	7.68	4.9	3.40	554	0.770
170-1039B	170-1039B-23X-5,135-150	206.85	62	35.6	38.3	0.434	1.830	0.389	0.454	260	12	7.29	2.6	3.50	554	0.780
170-1039B	170-1039B-29X-3,135-150	261.75	60	39.3	39.9	0.461	1.982	0.413	0.472	260	10	7.55	2.1	3.50	554	0.850
170-1039B	170-1039B-32X-2,130-150	289.20	58	39.9	39.5	0.446	1.964	0.401	0.451	268	9	7.27	1.8	3.50	557	0.800
170-1039B	170-1039B-35X-3,130-150	319.50	58	40.2	38.8	0.448	2.020	0.401	0.458	241	10	7.60	1.8	3.50	558	0.800
170-1039C	170-1039C-2R-1,085-100	373.35	55	38.9	38.5	0.454	2.047	0.406	0.463	194	11	7.64	1.8	3.50	560	0.810
170-1039C	170-1039C-6R-4,128-142	416.98	55	41.0	40.6	0.440	1.884	0.384	0.468	155	16	7.97	1.6	3.50	557	0.790
170-1039C	170-1039C-7R-1,085-100	421.65	54	44.4	43.9	0.368	1.875	0.329	0.460	154	16	7.80	1.9	3.50	559	0.660
170-1040B	170-1040B-1H-3,135-150	4.35	80	37.2	36.9	0.591	2.045	0.529	0.457	81	26	7.67	6.2	3.25	548	1.080
170-1040B	170-1040B-2H-6,135-150	12.85	75	41.1	40.6	0.725	2.661	0.649			39	8.05	9.8	3.20	540	1.340
170-1040B	170-1040B-5X-2,135-150	29.85	72	42.4	41.9	0.381	1.447	0.341	0.387	81	37	7.82	13.7	3.65	575	0.740
170-1040B	170-1040B-6X-1,130-150	37.70	67	41.8	43.4							7.90	13.5	3.05	514
170-1040B	170-1040B-8X-1,074-084	55.94	60	46.9	46.3	0.414	1.780	0.371			48			3.00	514	0.810
170-1040B	170-1040B-12X-3,125-150	97.85	53	39.4	39.1	0.191	0.877	0.171			50	7.66	12.7	2.90	512	0.370
170-1040B	170-1040B-13X-2,120-150	101.80	61	41.3	40.9	0.177	0.828	0.158			51	8.04	12.1	2.90	502	0.350
170-1040B	170-1040B-20X-2,120-150	164.10	47	42.8	42.2	0.184	0.892	0.165	0.420	80	48	7.99	12.3	2.85	483	0.380
170-1040B	170-1040B-22X-2,120-150	183.30	45	42.4	42.0	0.137	0.675	0.123	0.406	76	47	8.10	9.2	2.80	485	0.280
170-1040C	170-1040C-6R-4,120-150	213.00	44	36.1	35.9						148			2.80	487
170-1040C	170-1040C-13R-4,000-035	279.95	41	37.8	37.5	0.154	0.784	0.139	0.488	102	148			3.00	513	0.300
170-1040C	170-1040C-22R-4,115-150	367.05	39	36.4	36.1						88			2.96	512
170-1040C	170-1040C-23R-1,115-150	372.15	57	38.7	36.4	0.664	2.939	0.585	0.455	157	19	7.97	35.6	3.40	563	1.180
170-1040C	170-1040C-24R-2,120-150	381.80	57	40.8	40.2	0.645	2.965	0.678	0.465	132	20	8.00	39.3	3.40	562	1.150
170-1040C	170-1040C-25R-1,125-150	391.45	58	37.8	37.3	0.691	3.087	0.619	0.458	100	26	7.79	35.8	3.40	558	1.240
170-1040C	170-1040C-26R-1,125-150	401.05	55	42.9	42.5	0.656	2.958	0.587	0.454	85	26	7.79	31.9	3.30	582	1.190
170-1040C	170-1040C-27R-3,125-150	413.65	55	40.4	40.0	0.602	2.715	0.538	0.461	90	28	7.79	22.0	3.30	554	1.090
170-1040C	170-1040C-28R-2,125-150	423.35	53	41.7	41.3	0.488	2.242	0.437	0.471	97	28	7.79	17.5	3.35	565	0.850
170-1040C	170-1040C-31R-3,125-150	452.05	53	41.8	41.4	0.475	2.162	0.425	0.479	149	28	7.87	13.3	3.35	546	0.870
170-1040C	170-1040C-33R-5,120-150	474.20	52	42.0	41.6	0.452	2.096	0.405	0.477	191	25	7.98	7.0	3.35	549	0.820
170-1040C	170-1040C-43R-1,130-150	564.70	49	38.9	38.6	0.444	2.114	0.339	0.485	280	11	7.68	2.8	3.50	560	0.790
170-1040C	170-1040C-52R-2,125-150	652.75	48	39.6	39.3	0.480	2.306	0.430	0.489	280	12	9.44	1.8	3.50	558	0.860
170-1041A	170-1041A-1H-1,145-150	1.45	80	36.7	36.4	0.647	2.239	0.579	0.486	83	28	7.98	5.3	3.40	547	1.180
170-1041A	170-1041A-1H-4,140-150	5.90	79	87.9	37.5	0.690	2.417	0.618	0.468	75	23	8.09	13.2	3.30	544	1.270
170-1041A	170-1041A-2H-1,135-150	8.75	77	40.8	40.4	0.520	1.865	0.166	0.472	74	24	8.28	21.1	3.30	532	0.980
170-1041A	170-1041A-8X-3,130-190	54.90	64	40.3	39.9	0.302	1.248	0.270	0.435	69	38	7.90	27.5	2.80	474	0.640
170-1041A	170-1041A-15X-6,058-078	123.10	52	40.4	40.0	0.253	1.173	0.227			43	8.03	25.9	2.45	401	0.630
170-1041B	170-1041B-2R-4,031-133	168.91	46	43.3	42.8	0.243	1.188	0.218	0.358	48	68	7.95	22.2	2.10	388	0.560
170-1041B	170-1041B-8R-1,103-133	223.33	43	38.8	38.5	0.240	1.203	0.215	0.317	42	103	7.85	15.5	2.05	353	0.680
170-1041B	170-1041B-12R-3,114-139	264.18	41	39.8	39.5	0.227	1.157	0.203	0.317	46	135	7.76	15.9	2.00	380	0.630
170-1041B	170-1041B-21R-3,000-035	350.60	37	42.4	42.1	0.175	0.921	0.157			252	7.82	6.6	1.95	351	0.500
170-1043A	170-1043A-1H-2,140-150	2.90	80	34.7	34.4	0.808	2.097	0.543	0.476	85	23	7.77	4.1	3.40	548	1.110
170-1043A	170-1043A-1H-4,140-150	5.90	78	32.9	32.7	0.881	2.414	0.610	0.472	102	16	7.76	18.3	3.30	545	1.250
170-1043A	170-1043A-2H-1,140-150	9.40	78	33.5	33.3	0.823	2.209	0.558	0.469	90	18	7.71	18.2	8.35	551	1.130
170-1043A	170-1043A-12X-4,115-150	105.55	55	39.4	38.3	0.490	2.246	0.446	0.465	94	24	8.00	19.3	3.20	551	0.900
170-1043A	170-1043A-14X-4,115-150	124.85	52	37.2	36.9	0.420	1.947	0.376	0.471	101	26	8.02	18.8	3.20	557	0.750
170-1043A	170-1043A-18X-2,115-150	160.15	67	38.8	38.5	0.562	2.252	0.503	0.489	108	27	7.79	13.7	3.40	558	1.010
170-1043A	170-1043A-19H-3,095-120	171.05	67	39.3	38.8	0.577	2.312	0.517	0.495	108	26	7.76	14.7	3.40	555	1.040
170-1043A	170-1043A-20X-2,130-150	179.40	66	39.9	39.6	0.488	1.976	0.437	0.488	121	27	7.95	12.9	3.40	554	0.890
170-1043A	170-1043A-22X-5,130-150	202.90	65	41.0	40.6	0.482	2.012	0.441	0.487	143	28	7.30	10.3	3.40	555	0.880
170-1043A	170-1043A-23X-4,130-150	211.00	62	41.9	41.5	0.495	2.087	0.443	0.473	154	27	7.89	12.3	3.40	556	0.890
170-1043A	170-1043A-24X-3,125-150	219.05	64	42.2	41.7	0.498	2.058	0.448	0.483	189	25	7.77	11.1	3.40	555	0.900
170-1043A	170-1043A-30X-1,120-150	273.80	60	40.1	39.7	0.449	1.926	0.401	0.474	235	18	7.55	2.8	3.40	551	0.810