Table T19. Correlation of reflection traveltime with the lithostratigraphic column, Site 1179.
Seismic line 2-1 | Seismic line 2-4 | Reflection strength | Correlation | |||||||
---|---|---|---|---|---|---|---|---|---|---|
One-way traveltime (s) | Depth* (mbsf) | Velocity (m/s) | One-way traveltime (s) | Depth* (mbsf) | Velocity (m/s) | |||||
Calculated†
|
Interval
|
Calculated†
|
Interval
|
|||||||
0 | 0 | 1590 | 0 | 0 | 1590 | |||||
1556 | 1556 | |||||||||
0.018 | 28 | 1605 | 0.018 | 28 | 1605 | Weak | ? | |||
1600 | ||||||||||
0.038 | 60 | 1622 | 1607 | Weak | Small perturbation in PWL velocity at 60 mbsf | |||||
1649 | 0.057 | 91 | 1639 | Weak | Very slight change in GRA density | |||||
0.075 | 121 | 1655 | 1615 | Weak | Very slight increase in velocity at 120 mbsf | |||||
1651 | ||||||||||
0.100 | 162 | 1677 | 0.100 | 162 | 1677 | Weak | Slight increase in density at 155 mbsf | |||
1669 | 1669 | |||||||||
0.115 | 187 | 1691 | 0.115 | 187 | 1691 | Weak | Increases in velocity and density at 185 mbsf | |||
1684 | 1687 | |||||||||
0.132 | 215 | 1707 | 0.138 | 226 | 1713 | Weak | Unit I/Unit II at ~221-222 (221.5) m: increase in density at 215-225 mbsf | |||
1701 | 1706 | |||||||||
0.152 | 249 | 1726 | 0.155 | 255 | 1729 | Strong | Unit II/Unit III at ~247 m: abrupt changes in velocity and density at 245 mbsf | |||
1716 | 1721 | |||||||||
0.162 | 267 | 1736 | 0.170 | 280 | 1744 | Weak | Changes in PWL velocity, GRA density, and NGR at 260-270 mbsf | |||
1725 | 1733 | |||||||||
0.172 | 284 | 1746 | 0.180 | 298 | 1754 | Strong | Unit III/Unit IV: top of chert at ~283 mbsf | |||
1755 | 1764 | |||||||||
0.220 | 368 | 1795 | 0.230 | 386 | 1806 | Strong | Unit IV/Unit V: top of basement at ~375 mbsf | |||
1795 | ||||||||||
0.250 | 422 | 1828 | Moderate | ? |
Notes: * = Depths estimated using z = -3030 x ln (1 - 0.52t) (Carlson et al., 1986). † = Velocity estimated from v (z) = 1590 exp (0.00033z) (Carlson et al., 1986). PWL = P-wave logger, GRA = gamma-ray attenuation, NGR = natural gamma ray. ? = no correlation. This table is also available in ASCII format.