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Torres, Marta E; Teichert, Barbara M A; Tréhu, Anne M; Borowski, Walter S; Tomaru, Hitoshi (2004): (Table 1) Depth to basement, accreted melange, bottom simulating reflector and sediment penetration in meters below seafloor [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.770069, Supplement to: Torres, ME et al. (2004): Relationship of pore water freshening to accretionary processes in the Cascadia margin: Fluid sources and gas hydrate abundance. Geophysical Research Letters, 31(22), 1-4, https://doi.org/10.1029/2004GL021219

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Abstract:
Drilling in the Cascadia accretionary complex enable us to evaluate the contribution of dehydration reactions and gas hydrate dissociation to pore water freshening. The observed freshening with depth and distance from the prism toe is consistent with enhanced conversion of smectite to illite, driven by increase in temperature and age of accreted sediments. Although they contain gas hydrate -as evidenced by discrete low chloride spikes- the westernmost sites drilled on Hydrate Ridge show no freshening trend with depth. Strontium data reveal that all the mélange samples contain deep fluids modified by reaction with the subducting oceanic crust. Thus we infer that, at the westernmost sites, accretion is too recent for the sediments to have undergone significant illitization. Our data demonstrate that a smooth decrease in dissolved chloride with depth cannot generally be used to infer the presence or to estimate the amount of gas hydrate in accretionary margins.
Project(s):
Coverage:
Median Latitude: 45.682237 * Median Longitude: -125.710398 * South-bound Latitude: 44.570217 * West-bound Longitude: -127.730333 * North-bound Latitude: 48.732067 * East-bound Longitude: -125.074000
Date/Time Start: 1992-09-27T00:00:00 * Date/Time End: 2002-09-01T00:00:00
Minimum Elevation: -2656.7 m * Maximum Elevation: -685.1 m
Event(s):
146-888  * Latitude: 48.166800 * Longitude: -126.663117 * Date/Time Start: 1992-09-27T00:00:00 * Date/Time End: 1992-10-05T00:00:00 * Elevation: -2527.0 m * Penetration: 1176.4 m * Recovery: 374.6 m * Location: North Pacific Ocean * Campaign: Leg146 * Basis: Joides Resolution * Method/Device: Composite Core (COMPCORE) * Comment: 66 cores; 576.4 m cored; 600 m drilled; 65% recovery
146-889  * Latitude: 48.732067 * Longitude: -126.869850 * Date/Time Start: 1992-10-05T00:00:00 * Date/Time End: 1992-10-18T00:00:00 * Elevation: -1324.2 m * Penetration: 1270.8 m * Recovery: 284.6 m * Location: North Pacific Ocean * Campaign: Leg146 * Basis: Joides Resolution * Method/Device: Composite Core (COMPCORE) * Comment: 68 cores; 538.8 m cored; 384.5 m drilled; 52.8% recovery
146-892  * Latitude: 44.674317 * Longitude: -125.118817 * Date/Time Start: 1992-11-06T00:00:00 * Date/Time End: 1992-11-17T00:00:00 * Elevation: -685.1 m * Penetration: 753 m * Recovery: 155.2 m * Location: North Pacific Ocean * Campaign: Leg146 * Basis: Joides Resolution * Method/Device: Composite Core (COMPCORE) * Comment: 42 cores; 353 m cored; 178.5 m drilled; 44% recovery
Comment:
Distance to the prism toe in kilometers +-1.
Parameter(s):
#NameShort NameUnitPrincipal InvestigatorMethod/DeviceComment
Event labelEvent
Depth, bottom/maxDepth botmTorres, Marta EBasement
Lithology/composition/faciesLithologyTorres, Marta EMelange
Depth, bottom/maxDepth botmTorres, Marta EBSR
Penetration depthPenetr depthmTorres, Marta E
DistanceDistancekmTorres, Marta EDistance to Prism Toe
Size:
36 data points

Data

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


Event

Depth bot [m]
(Basement)

Lithology
(Melange)

Depth bot [m]
(BSR)

Penetr depth [m]

Distance [km]
(Distance to Prism Toe)
168-1027 608not present608
146-888 850not present566
204-1245 47013454012.5
204-1246 28011418013.5
204-1247 12127012.5
204-1244 24012438015.0
204-1252 11526017.0
146-892 ~707417818.0
204-1251 30019344519.0
146-889 16022538620.0