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Su, Xin; Baumann, Karl-Heinz; Thiede, Jörn (2000): (Table T4) Nannofossil datums and ages of ODP Leg 168 sites [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.788797, Supplement to: Su, X et al. (2000): Calcareous nannofossils from Leg 168: biochronology and diagenesis. In: Fisher, A; Davis, EE; Escutia, C (eds.) Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 168, 1-11, https://doi.org/10.2973/odp.proc.sr.168.015.2000

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Abstract:
A study on late Pliocene and Quaternary calcareous nannofossils from the eastern flank of the Juan de Fuca Ridge was carried out to provide a detailed biochronology for sediments recovered during Leg 168 and to investigate the effects of hydrothermal circulation and turbidite activity on diagenesis of nannofossils. Through high-resolution stratigraphical analysis, 10 Quaternary nannofossil events were determined and a detailed biochronology of the Quaternary was obtained. Upper Pliocene sediments were also recovered but did not contain any upper Pliocene marker species, such as Discoaster species. However, an age of younger than 3.2 Ma was estimated for these sediments based on evidences of nannofossil assemblages. Based on the resolved biostratigraphy, sedimentation rates of sediment sequences at these 10 sites and their variations were determined. A sedimentation hiatus between basal sediments and basements in this young seafloor region was observed. Relative abundance of nannofossils in sediments is largely changed by dilution of turbiditic materials. Evidence suggests that variations in relative group abundance of nannofossils in the Juan de Fuca Ridge, affected by dilution of turbiditic materials, does not reflect the real variation in production of this group of microfossils.
Observations of this study suggest that calcite overgrowth of nannofossils is controlled by temperature, heat flow, thermal gradient in sediments, and the variation in composition of pore water, as well as the supply of calcite materials in sediments. These results provide a detailed knowledge about effects of low-temperature hydrothermal alteration on diagenesis of nannofossils. Downhole variations in dissolution degree of nannofossils in sediment sequences at all Leg 168 sites were presented and compared with pH profiles. The correlation between these data indicates that nannofossils are very sensitive to variations in pH units in sediments. A reduction of pH will result in dissolution of nannofossils. Variations in pH units are induced by hydrothermal circulation as a result of a number of interactions between water/sediments and water/basement. The dissolution of nannofossils at Sites 1031 and 1032 were directly affected further by the pore-water upward flows at these two sites. A few records of nannofossil preservation suggest that the effects of hydrothermal activity on diagenesis of nannofossils might involve more complicated processes and mechanisms that we do not understand yet.
Project(s):
Ocean Drilling Program (ODP)
Coverage:
Median Latitude: 47.848415 * Median Longitude: -128.381033 * South-bound Latitude: 47.756767 * West-bound Longitude: -128.792000 * North-bound Latitude: 47.917300 * East-bound Longitude: -127.730333
Date/Time Start: 1996-06-23T09:15:00 * Date/Time End: 1996-08-11T11:57:00
Minimum DEPTH, sediment/rock: 4.50 m * Maximum DEPTH, sediment/rock: 451.85 m
Event(s):
168-1023A  * Latitude: 47.917300 * Longitude: -128.792000 * Date/Time Start: 1996-06-23T09:15:00 * Date/Time End: 1996-06-25T02:15:00 * Elevation: -2593.3 m * Penetration: 194.5 m * Recovery: 193.05 m * Location: Juan de Fuca Ridge, North Pacific Ocean * Campaign: Leg168 * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 22 cores; 194.5 m cored; 0 m drilled; 99.3 % recovery
168-1024B  * Latitude: 47.904600 * Longitude: -128.752000 * Date/Time Start: 1996-06-25T09:15:00 * Date/Time End: 1996-06-26T07:45:00 * Elevation: -2614.0 m * Penetration: 169.6 m * Recovery: 170.11 m * Location: Juan de Fuca Ridge, North Pacific Ocean * Campaign: Leg168 * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 18 cores; 169.6 m cored; 0 m drilled; 100.3 % recovery
168-1025B  * Latitude: 47.883300 * Longitude: -128.650000 * Date/Time Start: 1996-06-26T19:30:00 * Date/Time End: 1996-06-27T13:45:00 * Elevation: -2313.6 m * Penetration: 99.5 m * Recovery: 90.98 m * Location: Juan de Fuca Ridge, North Pacific Ocean * Campaign: Leg168 * Basis: Joides Resolution * Method/Device: Drilling/drill rig (DRILL) * Comment: 11 core; 99.5 m cored; 0 m drilled; 91.4 % recovery
Parameter(s):
#NameShort NameUnitPrincipal InvestigatorMethod/DeviceComment
1 Event labelEvent
2 Longitude of eventLongitude
3 Latitude of eventLatitude
4 Elevation of eventElevationm
5 Sample commentSample commentSu, Xin
6 Ageprofile Datum DescriptionAgeprof dat desSu, XinT = top, B = bottom
7 Age modelAge modelkaSu, XinAge model, GPTS (geomagnetic polarity timescale), Cande and Kent (1995)
8 DEPTH, sediment/rockDepth sedmGeocode – mbsf
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
125 data points

Data

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

1 
Event		2 
Longitude		3 
Latitude		4 
Elevation [m]		5 
Sample comment		6 
Ageprof dat des		7 
Age model [ka]		8 
Depth sed [m]
168-1023A -128.792047.9173-2593B acme Emiliania huxleyi9043.93
168-1023A-128.792047.9173-2593B Emiliania huxleyi280110.02
168-1023A-128.792047.9173-2593T P. lacunosa460154.80
168-1024B -128.752047.9046-2614B acme Emiliania huxleyi9031.85
168-1024B-128.752047.9046-2614B Emiliania huxleyi28074.25
168-1024B-128.752047.9046-2614T P. lacunosa460140.78
168-1025B -128.650047.8833-2314B acme Emiliania huxleyi905.08
168-1025B-128.650047.8833-2314B Emiliania huxleyi28031.49
168-1025B-128.650047.8833-2314T P. lacunosa46077.45
168-1030B -128.561047.8975-2573B acme Emiliania huxleyi9011.94
168-1030B-128.561047.8975-2573B Emiliania huxleyi28027.85
168-1030B-128.561047.8975-2573T P. lacunosa46033.59
168-1031A -128.566047.8900-2588B acme Emiliania huxleyi904.50
168-1031A-128.566047.8900-2588B Emiliania huxleyi28010.67
168-1031A-128.566047.8900-2588T P. lacunosa46018.36
168-1031A-128.566047.8900-2588B Gephyrocapsa caribbeanica76025.79
168-1031A-128.566047.8900-2588T Reticulofenestra asanoi90036.74
168-1031A-128.566047.8900-2588B Reticulofenestra asanoi115038.51
168-1028A -128.504047.8580-2659B acme Emiliania huxleyi9031.00
168-1028A-128.504047.8580-2659B Emiliania huxleyi28059.97
168-1028A-128.504047.8580-2659T P. lacunosa46091.93
168-1028A-128.504047.8580-2659B Gephyrocapsa caribbeanica760102.81
168-1028A-128.504047.8580-2659B Reticulofenestra asanoi1150124.90
168-1028A-128.504047.8580-2659T Gephyrocapsa lumina1230129.77
168-1029A -128.376047.8317-2653B acme Emiliania huxleyi9010.65
168-1029A-128.376047.8317-2653B Emiliania huxleyi28035.19
168-1029A-128.376047.8317-2653T P. lacunosa46096.92
168-1029A-128.376047.8317-2653B Gephyrocapsa caribbeanica760161.75
168-1029A-128.376047.8317-2653T Reticulofenestra asanoi900192.88
168-1029A-128.376047.8317-2653B Reticulofenestra asanoi1150207.80
168-1029A-128.376047.8317-2653T Gephyrocapsa lumina1230216.55
168-1029A-128.376047.8317-2653T Calcidiscus macintyrei1580219.55
168-1032A -128.122047.7796-2645B Gephyrocapsa caribbeanica760228.04
168-1032A-128.122047.7796-2645T Gephyrocapsa lumina1230276.43
168-1026 -127.757047.7654-2658depths composed of Holes B and CB acme Emiliania huxleyi9027.43
168-1026-127.757047.7654-2658depths composed of Holes B and CB Emiliania huxleyi280109.06
168-1026-127.757047.7654-2658depths composed of Holes B and CT P. lacunosa460143.16
168-1026-127.757047.7654-2658depths composed of Holes B and CB Gephyrocapsa caribbeanica760197.74
168-1026-127.757047.7654-2658depths composed of Holes B and CT Reticulofenestra asanoi900210.43
168-1026-127.757047.7654-2658depths composed of Holes B and CB Reticulofenestra asanoi1150219.06
168-1026-127.757047.7654-2658depths composed of Holes B and CT Gephyrocapsa lumina1230223.96
168-1026-127.757047.7654-2658depths composed of Holes B and CT Helicosphaera sellii1550227.72
168-1026-127.757047.7654-2658depths composed of Holes B and CT Calcidiscus macintyrei1580228.70
168-1027 -127.730347.7568-2657depths composed of Holes B and CB acme Emiliania huxleyi9041.09
168-1027-127.730347.7568-2657depths composed of Holes B and CB Emiliania huxleyi280147.27
168-1027-127.730347.7568-2657depths composed of Holes B and CT P. lacunosa460198.61
168-1027-127.730347.7568-2657depths composed of Holes B and CB Gephyrocapsa caribbeanica760257.75
168-1027-127.730347.7568-2657depths composed of Holes B and CT Reticulofenestra asanoi900361.43
168-1027-127.730347.7568-2657depths composed of Holes B and CB Reticulofenestra asanoi1150401.42
168-1027-127.730347.7568-2657depths composed of Holes B and CT Gephyrocapsa lumina1230404.43
168-1027-127.730347.7568-2657depths composed of Holes B and CT Helicosphaera sellii1550428.61
168-1027-127.730347.7568-2657depths composed of Holes B and CT Calcidiscus macintyrei1580436.41
168-1027-127.730347.7568-2657depths composed of Holes B and CB Gephyrocapsa lumina1680451.85