Table 21. Mean paleolatitudes.
|
Age
(Ma) |
Depth range
(mbsf)
|
Mean depth (mbsf)
|
N
|
A-mean
paleolatitude |
SB
|
B-mean
paleolatitude |
Unbiased
mean paleolatitude
|
SSV
|
SR
|
ST
|
Std. error
of unbiased mean
|
95% conf.
limits for mean paleolatitude
|
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Site 998 (19.49°N, 277.06°E) | ||||||||||||
| 2.1 | 0-100 | 40.1 | 14 | 19.0 | 2.2 | 16.1 | 19.2 | 1.7 | 2.2 | 3.0 | ±3.0 | +5.9/-6.0 |
| 38.0 | 582-734 | 655.1 | 10 | 14.0 | 2.2 | 11.6 | 14.1 | 2.0 | 2.2 | 3.0 | +3.0/-3.2 | +5.9/-6.6 |
| 50.0 | 848-903 | 877.1 | 33 | 8.5 | 1.0 | 8.6 | 7.9 | 1.1 | 1.1 | 2.3 | +2.7/-3.5 | +5.1/-7.9 |
| Site 999 (12.74°N, 281.26°E) | ||||||||||||
| 0.71 | 0-50 | 26.8 | 12 | 13.0 | 1.7 | 13.0 | 13.0 | 1.8 | 1.8 | 2.7 | +2.8/-2.9 | +5.4/-6.1 |
| 2.1 | 50-100 | 70.1 | 18 | 12.3 | 2.0 | 10.2 | 12.3 | 1.5 | 2.0 | 2.8 | +2.9/-3.2 | +5.7/-6.9 |
| 3.8 | 100-200 | 125.2 | 11 | 13.0 | 2.8 | 10.8 | 13.0 | 1.9 | 2.8 | 3.4 | +3.6/-3.8 | +6.9/-8.5 |
| 8.9 | 200-300 | 245.4 | 3 | 19.4 | 7.4 | 23.0 | 19.6 | 3.7 | 7.4 | 7.7 | +7.7/-7.9 | +14.8/-19.6 |
| 22.7 | 579-600 | 581.2 | 6 | 10.2 | 1.3 | 9.7 | 10.0 | 2.6 | 2.6 | 3.3 | +3.6/-4.3 | +6.8/-10.0 |
| 27.0 | 600-700 | 637.6 | 13 | 7.1 | 1.4 | 5.7 | 6.0 | 1.8 | 1.8 | 2.7 | +3.5/-6.0 | +6.4/-6.0 |
| 36.0 | 700-800 | 755.7 | 14 | 8.0 | 1.8 | 7.5 | 7.2 | 1.7 | 1.8 | 2.7 | +3.3/-5.1 | +6.1/7.2 |
| 44.0 | 800-900 | 842.4 | 18 | 6.2 | 0.9 | 6.1 | 4.4 | 1.5 | 1.5 | 2.5 | +3.8/-4.4 | +6.6/-4.4 |
| 50.0 | 900-1000 | 924.1 | 8 | 6.3 | 1.3 | 6.3 | 4.6 | 2.3 | 2.3 | 3.0 | +4.4/-4.6 | +7.6/-4.6 |
| 66.0 | 1000-1066 | 1052.8 | 10 | 6.2 | 1.1 | 4.6 | 4.4 | 2.0 | 2.0 | 2.8 | +4.2/-4.4 | +7.3/-4.4 |
| Site 1001 (15.76°N, 285.09°E) | ||||||||||||
| 54.0 | 160-211 | 183.0 | 10 | 7.5 | 2.8 | 8.6 | 6.5 | 2.0 | 2.8 | 3.4 | +4.3/-6.5 | +7.8/-6.5 |
| 57.0 | 217-331 | 284.2 | 94 | 5.0 | 0.3 | 5.6 | 5.0 | — | 0.3 | 2.0 | ±2.0 | ±3.9 |
| (Chron 24R-27N) | ||||||||||||
| 65.0 | 331-396 | 361.7 | 68 | 4.7 | 0.4 | 4.4 | 4.7 | — | 0.4 | 2.0 | ±2.0 | ±3.9 |
| (Chron 27R-31R) | ||||||||||||
| 74.0 | 396-484 | 440.3 | 96 | 7.5 | 0.6 | 5.6 | 6.5 | 0.7 | 0.7 | 2.1 | +2.7/-4.2 | +5.0/-6.5 |
| 81.0 (basalt)1 | 487-517 | 502.0 | 230 (12*) | 8.0 | 1.5 | 4.5 | 2.6 | 2.6 | 3.3 | +5.8/-4.5 | +9.7/-4.5 | |
| 81.0 (basalt)2 | 487-517 | 502.0 | 230 (12*) | 4.3 | 2.5 | 4.3 | 2.6 | 2.6 | 3.3 | ±3.3 | ±6.5 | |
Notes: N = number of
samples; A-Mean paleolatitude = the mean computed from all N paleolatitude
(sample or unit) estimates; B-Mean paleolatitude = the mean computed from two
values: (1) the mean paleolatitude of data with positive inclinations, and (2)
the mean paleolatitude obtained from the absolute values of data with negative
inclinations; SB = the standard error for the A-mean paleolatitude
(the between-sample or between-basalt-unit standard error). The 95% confidence
limits for the A-mean and B-mean paleolatitudes can be obtained by multiplying SR
by 1.96. SSV = the expected univariate standard error for N samples
assuming the dispersion caused by secular variation is described with a
precision parameter of 40; SR = the standard error attributed to
random errors, which is taken to be the larger of the SB or SSV;
SS = the standard error attributed to systematic errors. We assume
this to be 2°, to account for systematic deviations of the borehole from
vertical; ST = the total standard error used for the unbiased mean,
which is = 
. * =
there were 230 inclination estimates from the split-core basalt samples. These
were grouped into 12 independent secular variation units. 81 Ma (basalt)1:
no assumption is made about polarity of the SV units; 81 Ma (basalt)2:
polarity assumed to be constant during the extrusion of 12 SV units.