Citation:

odp.proc.sr.134.040.1994

Name: (Table 1) Organic geochemistry of ODP Hole 134-832B and Site 134-833
Published: 1994
License: https://creativecommons.org/licenses/by/3.0/

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Abstract:

Ocean Drilling Program (ODP) Leg 134 was located in the central part of the New Hebrides Island Arc, in the Southwest Pacific. Here the d'Entrecasteaux Zone of ridges, the North d'Entrecasteaux Ridge and South d'Entrecasteaux Chain, is colliding with the arc. The region has a Neogene history of subduction polarity reversal, ridge-arc collision, and back-arc spreading.

The reasons for drilling in this region included the following: (1) to determine the differences in the style and time scale of deformation associated with the two ridge-like features (a fairly continuous ridge and an irregularly topographic seamount chain) that are colliding with the central New Hebrides Island Arc; (2) to document the evolution of the magmatic arc in relation to the collision process and possible Neogene reversal of subduction; and (3) to understand the process of dewatering of a small accretionary wedge associated with ridge collision and subduction. Seven sites were occupied during the leg, five (Sites 827-831) were located in the d'Entrecasteaux Zone where collision is active. Three sites (Sites 827, 828, and 829) were located where the North d'Entrecasteaux Ridge is colliding, whereas two sites (Sites 830 and 831) were located in the South d'Entrecasteaux Chain collision zone. Sites 828 (on North d'Entrecasteaux Ridge) and 831 (on Bougainville Guyot) were located on the Pacific Plate, whereas all other sites were located on a microplate of the North Fiji Basin. Two sites (Sites 832 and 831) were located in the intra-arc North Aoba Basin.

Results of Leg 134 drilling showed that forearc deformation associated with the North d'Entrecasteaux Ridge and South d'Entrecasteaux Chain collision is distinct and different. The d'Entrecasteaux Zone is an Eocene subduction/obduction complex with a distinct submerged island arc. Collision and subduction of the North d'Entrecasteaux Ridge results in off scraping of ridge material and plating of the forearc with thrust sheets (flakes) as well as distinct forearc uplift. Some offscraped sedimentary rocks and surficial volcanic basement rocks of the North d'Entrecasteaux Ridge are being underplated to the New Hebrides Island forearc. In contrast, the South d'Entrecasteaux Chain is a serrated feature resulting in intermittent collision and subduction of seamounts. The collision of the Bougainville Guyot has indented the forearc and appears to be causing shortening through thrust faulting.

In addition, we found that the Quaternary relative convergence rate between the New Hebrides Island Arc at the latitude of Espiritu Santo Island is as high as 14 to 16 cm/yr. The northward migration rate of the d'Entrecasteaux Zone was found the be ~2 to 4 cm/yr based on the newly determined Quaternary relative convergence rate. Using these rates we established the timing of initial d'Entrecasteaux Zone collision with the arc at ~3 Ma at the latitude of Epi Island and fixed the impact of the North d'Entrecasteaux Ridge upon Espiritu Santo Island at early Pleistocene (between 1.89 and 1.58 Ma).

Dewatering is occurring in the North d'Entrecasteaux Ridge accretionary wedge, and the wedge is dryer than other previously studied accretionary wedges, such as Barbados. This could be the result of less sediment being subducted at the New Hebrides compared to the Barbados.

Project(s):

Ocean Drilling Program (ODP)

Coverage:

Median Latitude: -14.849333 * Median Longitude: 167.777667 * South-bound Latitude: -14.876000 * West-bound Longitude: 167.573000 * North-bound Latitude: -14.796000 * East-bound Longitude: 167.880000

Date/Time Start: 1990-11-23T03:30:00 * Date/Time End: 1990-12-14T00:30:00

Minimum Elevation: -3101.0 m * Maximum Elevation: -2640.0 m

Event(s):

134-832B * Latitude: -14.796000 * Longitude: 167.573000 * Date/Time Start: 1990-11-23T03:30:00 * Date/Time End: 1990-12-01T00:00:00 * Elevation: -3101.0 m * Penetration: 1106.7 m * Recovery: 450.95 m * Location: Coral Sea * Campaign: * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 100 cores; 962.3 m cored; 0 m drilled; 46.9 % recovery

134-833A * Latitude: -14.876000 * Longitude: 167.880000 * Date/Time Start: 1990-12-02T05:00:00 * Date/Time End: 1990-12-03T22:30:00 * Elevation: -2641.0 m * Penetration: 199.5 m * Recovery: 97.75 m * Location: Coral Sea * Campaign: * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 26 cores; 199.5 m cored; 0 m drilled; 49 % recovery

134-833B * Latitude: -14.876000 * Longitude: 167.880000 * Date/Time Start: 1990-12-03T10:30:00 * Date/Time End: 1990-12-14T00:30:00 * Elevation: -2640.0 m * Penetration: 1001.1 m * Recovery: 519.54 m * Location: Coral Sea * Campaign: * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 99 cores; 923.7 m cored; 0 m drilled; 56.2 % recovery

Parameter(s):

#	Name	Short Name	Unit	Principal Investigator	Method/Device
1	Event label	Event
2	Sample code/label	Sample label		Greene, H Gary	DSDP/ODP/IODP sample designation
3	Pyrolysis temperature maximum	Tmax	°C	Greene, H Gary	Rock eval pyrolysis (Behar et al., 2001)
4	Hydrocarbon yield, S1 per unit sediment mass	S1 HC/sed	mg/g	Greene, H Gary	Rock eval pyrolysis (Behar et al., 2001)
5	Hydrocarbon yield, S2 per unit sediment mass	S2 HC/sed	mg/g	Greene, H Gary	Rock eval pyrolysis (Behar et al., 2001)
6	Carbon dioxide yield, S3 per unit sediment mass	S3 CO2/sed	mg/g	Greene, H Gary	Rock eval pyrolysis (Behar et al., 2001)
7	Hydrocarbon yield, S2/Carbon dioxide yield, S3	S2/S3		Greene, H Gary	Rock eval pyrolysis (Behar et al., 2001)
8	Carbon, organic, total	TOC	%	Greene, H Gary	Rock eval pyrolysis (Behar et al., 2001)
9	Hydrogen index, mass HC, per unit mass total organic carbon	HI, HC/TOC	mg/g	Greene, H Gary	Rock eval pyrolysis (Behar et al., 2001)
10	Oxygen index, mass CO2, per unit mass total organic carbon	OI, CO2/TOC	mg/g	Greene, H Gary	Rock eval pyrolysis (Behar et al., 2001)

License:

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

Size:

171 data points

Data

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

1 Event	2 Sample label	3 Tmax [°C]	4 S1 HC/sed [mg/g]	5 S2 HC/sed [mg/g]	6 S3 CO2/sed [mg/g]	7 S2/S3	8 TOC [%]	9 HI, HC/TOC [mg/g]	10 OI, CO2/TOC [mg/g]
134-832B	134-832B-9R-1,8-10	592	0.08	0.69	2.42	0.28	0.13	530	1861
134-832B	134-832B-17R-3,54-56	580	0.21	1.61	3.46	0.46	0.31	519	1116
134-832B	134-832B-18R-3,78-80	527	0.05	0.32	1.23	0.26	0.06	533	2050
134-832B	134-832B-19R-2,22-24	584	0.02	0.68	0.29	2.34	0.07	971	414
134-832B	134-832B-29R-3,12-13	593	0.28	1.05	0.49	2.14	0.11	954	445
134-832B	134-832B-30R-5,57-58	574	0.18	1.75	2.49	0.70	0.32	546	778
134-832B	134-832B-31R-3,127-129	578	0.08	0.83	4.36	0.19	0.34	244	1282
134-832B	134-832B-42R-2,110-112	582	0.05	0.51	2.17	0.23	0.12	425	1808
134-832B	134-832B-47R-1,40-41	588	0.07	0.79	2.26	0.34	0.12	658	1883
134-832B	134-832B-61R-5,40-42	589	0.12	0.55	1.45	0.37	0.09	611	1611
134-832B	134-832B-68R-CC,17-18	412	0.30	3.04	10.74	0.28	3.74	81	287
134-833A	134-833A-2H-3,145-150	445	0.01	0.39	4.12	0.09	0.12	325	3433
134-833A	134-833A-3H-2,122-124	400	0.10	0.70	3.45	0.20	0.18	388	1916
134-833A	134-833A-26X-2,53-57	593	0.16	0.77	2.75	0.28	0.13	592	2115
134-833B	134-833B-29R-1,40-42	360	0.10	0.39	2.10	0.18	0.12	325	1750
134-833B	134-833B-76R-3,10-11	325	0.19	0.74	0.94	0.78	0.14	528	671
134-833B	134-833B-77R-4,5-6	388	0.07	0.24	1.37	0.17	0.10	240	1370
134-833B	134-833B-78R-C1,6-8	343	0.07	0.33	0.94	0.35	0.09	366	1044
134-833B	134-833B-88R-1,105-106	526	0.00	0.13	0.53	0.24	0.14	92	378