Citation:

dsdp.proc.66.120.1982

Name: (Table 1) Suspected gas hydrate occurrence on DSDP Leg 66 Holes
Published: 1982
License: https://creativecommons.org/licenses/by/3.0/

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Abstract:

Evidence for naturally occurring methane hydrates was collected at three drill sites off the southern Mexico continental margin. The hydrates are manifested either by ice inclusions or, more often, as frozen porous volcanic ash and fine sands interlayered with muds. Gas generation from the ice inclusions and interstitial water of the frozen sediment was as high as about 7 ml of gas/ml of water. One large sample immediately placed in a sealed container released about 20 ml of gas/ml of water. All of these values are higher than may be accounted for by gas solubility at in situ conditions.

Measured thermal gradients place the bottom-simulating reflection (BSR) in this area very near the phase boundary for the methane hydrate system. This is consistent with earlier interpretations that the BSR is related to the hydrate/gas phase boundary.

Project(s):

Deep Sea Drilling Project (DSDP)

Coverage:

Median Latitude: 16.089033 * Median Longitude: -98.991333 * South-bound Latitude: 16.029000 * West-bound Longitude: -99.056500 * North-bound Latitude: 16.159300 * East-bound Longitude: -98.945300

Date/Time Start: 1979-04-08T00:00:00 * Date/Time End: 1979-04-20T00:00:00

Minimum DEPTH, sediment/rock: 88.950 m * Maximum DEPTH, sediment/rock: 364.250 m

Event(s):

66-490 * Latitude: 16.159300 * Longitude: -99.056500 * Date/Time: 1979-04-08T00:00:00 * Elevation: -1761.0 m * Penetration: 588.5 m * Recovery: 343.4 m * Location: North Pacific/TRANSITION ZONE * Campaign: * Basis: Glomar Challenger * Method/Device: Drilling/drill rig (DRILL) * Comment: 63 cores; 577 m cored; 9 m drilled; 59.5 % recovery

66-491 * Latitude: 16.029000 * Longitude: -98.972200 * Date/Time: 1979-04-13T00:00:00 * Elevation: -2883.0 m * Penetration: 542 m * Recovery: 389.4 m * Location: North Pacific/SLOPE * Campaign: * Basis: Glomar Challenger * Method/Device: Drilling/drill rig (DRILL) * Comment: 58 cores; 532.5 m cored; 4.5 m drilled; 73.1 % recovery

66-492 * Latitude: 16.078800 * Longitude: -98.945300 * Date/Time: 1979-04-20T00:00:00 * Elevation: -1935.0 m * Penetration: 279 m * Recovery: 177.5 m * Location: North Pacific/SLOPE * Campaign: * Basis: Glomar Challenger * Method/Device: Drilling/drill rig (DRILL) * Comment: 29 cores; 260.2 m cored; 0 m drilled; 68.2 % recovery

Comment:

Sediment depth is given in mbsf. H2S was not detected in any of the samples.

Parameter(s):

#	Name	Short Name	Unit	Principal Investigator	Method/Device	Comment
1	Event label	Event
2	Latitude of event	Latitude
3	Longitude of event	Longitude
4	Elevation of event	Elevation	m
5	Sample code/label	Sample label		Shipley, Thomas H
6	Depth, top/min	Depth top	m	Shipley, Thomas H
7	Depth, bottom/max	Depth bot	m	Shipley, Thomas H
8	DEPTH, sediment/rock	Depth sed	m			Geocode
9	Lithology/composition/facies	Lithology		Shipley, Thomas H
10	Pressure	P	GPa	Shipley, Thomas H	Estimated	Minimum estimated from hydrostatic gradient 99.7 atm/km water and 0.1 atm/m sediments. Original unit 1 atm = 1*1.03323 GPa, in situ
11	Temperature, in rock/sediment	t	°C	Shipley, Thomas H	Estimated	Estimated from measured bottom water temperatures and a gradient 2.2°/100 m (Shipley and Shephard, 1982), in situ
12	Ratio	Ratio		Shipley, Thomas H	Estimated	Hydrate gas-generating ratio, #1, measured, ml gas/ml sample, porosity correction (46%) is assumed for frozen sediments to correct to ml gas/ml water in interstitial water, in situ
13	Ratio	Ratio		Shipley, Thomas H	Estimated	Hydrate gas-generating ratio, #2, measured, ml gas/ml sample, porosity correction (46%) is assumed for frozen sediments to correct to ml gas/ml water in interstitial water, in situ
14	Ratio	Ratio		Shipley, Thomas H	Estimated	Hydrate gas-generating ratio, #1, porosity corrected, ml gas/ml sample, porosity correction (46%) is assumed for frozen sediments to correct to ml gas/ml water in interstitial water, in situ
15	Ratio	Ratio		Shipley, Thomas H	Estimated	Hydrate gas-generating ratio, #2, porosity corrected, ml gas/ml sample, porosity correction (46%) is assumed for frozen sediments to correct to ml gas/ml water in interstitial water, in situ
16	Carbon dioxide	CO2	%	Shipley, Thomas H
17	C1 hydrocarbons	C1	%	Shipley, Thomas H
18	C2 hydrocarbons	C2	%	Shipley, Thomas H
19	C3 hydrocarbons	C3	mg/kg	Shipley, Thomas H
20	C4 hydrocarbons	C4	ppmv	Shipley, Thomas H
21	C5 hydrocarbons	C5	ng/g	Shipley, Thomas H
22	C1/(C2+C3) hydrocarbon ratio	C1/(C2+C3)		Shipley, Thomas H
23	Description	Description		Shipley, Thomas H		Gas composition of actual hydrate, frozen material, or closest core liner gas available indicating core distance to frozen lithology in meters. Composition corrected for air components

License:

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

Size:

128 data points

Data

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

1 Event	2 Latitude	3 Longitude	4 Elevation [m]	5 Sample label	6 Depth top [m]	7 Depth bot [m]	8 Depth sed [m]	9 Lithology	10 P [GPa] (Minimum estimated from hydros...)	11 t [°C] (Estimated from measured botto...)	12 Ratio (Hydrate gas-generating ratio,...)	13 Ratio (Hydrate gas-generating ratio,...)	14 Ratio (Hydrate gas-generating ratio,...)	15 Ratio (Hydrate gas-generating ratio,...)	16 CO2 [%]	17 C1 [%]	18 C2 [%]	19 C3 [mg/kg]	20 C4 [ppmv]	21 C5 [ng/g]	22 C1/(C2+C3)	23 Description (Gas composition of actual hyd...)
66-490	16.1593	-99.0565	-1761	1	139.73	139.75	139.740	Ice Inclusion: Ice inclusions in mud near large wood fragment	196.3132	6	0.91		0.91		23.23	76.77						Gas released by ice inclusion
66-490	16.1593	-99.0565	-1761	2	145.40	145.75	145.575	Frozen Sediment: Frozen muddy to silty laminated volcanic ash	196.3132	6					3.00	97.00						Gas from core liner 0.45 m above frozen material
66-490	16.1593	-99.0565	-1761	3	166.50	166.85	166.675	Frozen Sediment: Frozen sandy to silty laminated ash layer, temperature -2° to -0.8°C	201.4794	7					1.56	98.19	0.25	11	8	3000	376	Gas from core liner 0.25 m below frozen material
66-490	16.1593	-99.0565	-1761	4	364.00	364.50	364.250	Frozen Sediment: Frozen bioturbated (mixed) mudstone and clayey ash, temperature 1.7°C 2 hr after core on deck	216.9778	11					0.47	99.21	0.26	249	217	34000	348	Gas from core line 0.30 m above frozen material
66-491	16.0290	-98.9722	-2883	5	88.90	89.00	88.950	Ice Inclusion: Ice blebs in mud	304.8021	4	7.22		7.22		1.62	98.34	0.03	55	42	22000	2809	Gas from core liner 2.00 m below ice inclusion
66-491	16.0290	-98.9722	-2883	6	162.70	163.15	162.925	Frozen Sediment: Frozen bubbling fine sand beds (10 cm and 15 cm), temperature 1 to 1.5 °C	315.1344	6					0.73	99.18	0.08	37	12	8000	1180	Gas from core liner 5.00 m above frozen material
66-491	16.0290	-98.9722	-2883	7	168.30	168.35	168.325	Ice Inclusion: Frozen mud and ice	315.1344	6	0.02		0.02		0.79	98.27	0.89	478	194	110000	100	Gas from core liner 4.10 m below frozen material
66-492	16.0788	-98.9453	-1935	8	140.95	141.10	141.025	Frozen Sediment: Frozen muddy laminated volcanic ash layer	211.8116	6	3.26		7.09		0.22	99.59	0.18	50	47	0	1200	Gas relased by frozen sediment
66-492	16.0788	-98.9453	-1935	9	169.50	169.57	169.535	Frozen Sediment: Frozen muddy laminated volcanic ash, temperature 0.8°C	216.9778	6	2.16	9.4	4.70	20.4	0.23	99.68	0.08	34	37	0	1200	Gas released by frozen sediment