Table 2. Comparison of Leg 165 40Ar/39Ar radiometric dates of tephra layers vs. biostratigraphic ages.
| Leg, hole, core, section, interval (cm) | Tephra layer |
|
Biostratigraphic datum ranges | Source of biostratigraphy | Biostratigraphic
age (Ma) |
Tephra | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Number of
grains
|
Depth (mbsf)
|
|
Age model
|
Interpolated
depth (mbsf)
|
Age
(Ma) |
Age
(Ma) |
Error (Ma)
|
Age range
(Ma) |
Rank
|
|||
| 165-1000A-16H-6, 21-22 | 6 | 144.01 | 1 | 120.05-148.55 | 3.80-4.37 | Nannofossils: 1 | 4.28 | 4.80 | 0.24 | 4.56-5.04 | 1 | |
| 2, 3 | 120.05-148.55 | 3.82-4.8 | Nannofossils: 1 | 4.64 | ||||||||
| 2, 4 | 120.05-148.55 | 3.82-4.56 | Nannofossils: 1 | 4.44 | ||||||||
| 165-998A-13H-3, 32-33 | 6 | 116.62 | 1 | 113.90-116.85 | 6.50-7.24 | Nannofossils: 1 | 7.18 | 24.42 | 0.25 | 24.17-24.67 | 4 | |
| 2 | 113.90-116.85 | 6.76-7.39 | Nannofossils: 1 | 7.34 | ||||||||
| 5 | 113.90-116.85 | 6.84-7.39 | Nannofossils: 1 | 7.35 | ||||||||
| 7 | 113.00-121.20 | 5.875-6.555 | Paleomagnetism 3* | 6.18 | ||||||||
| 7 | 110.05-122.40 | 5.230-6.919 | Paleomagnetism 3* | 6.13 | ||||||||
| 165-998A-13H-5, 123-124 | 5 | 120.53 | 1 | 116.85-126.40 | 7.24-7.80 | Nannofossils: 1 | 7.46 | 7.93 | 0.81 | 7.12-8.74 | 2 | |
| 2, 4 | 116.85-126.40 | 7.39-7.73 | Nannofossils: 1 | 7.52 | ||||||||
| 7 | 113.00-121.20 | 5.875-6.555 | Paleomagnetism 3* | 6.50 | ||||||||
| 7 | 110.05-122.40 | 5.230-6.919 | Paleomagnetism 3* | 6.66 | ||||||||
| 165-1000A-28H-1, 88-89 | 5 | 251.18 | 1 | 250.55-286.05 | 7.24-8.35 | Nannofossils: 1 | 7.26 | 7.46 | 0.16 | 7.30-7.62 | 1 | |
| 2 | 250.55-286.05 | 7.39-8.20 | Nannofossils: 1 | 7.40 | ||||||||
| 165-999A-27X-2, 150 | 17 | 242.10 | 1 | 231.61-245.71 | 8.35-8.43 | Nannofossils: 1 | 8.41 | 8.50 | 0.16 | 8.34-8.66 | 1 | |
| 2, 1 | 231.61-245.71 | 8.20-8.43 | Nannofossils: 1 | 8.37 | ||||||||
| 3 | 231.61-245.71 | 8.6-8.7 | Nannofossils: 1 | 8.67 | ||||||||
| 6 | 237.54-265.56 | 8.58-9.82 | Foraminifers: 2 | 8.78 | ||||||||
| 3 | 237.54-265.56 | 8.3-10.9 | Foraminifers: 2 | 8.68 | ||||||||
| 6 | 237.54-269.11 | 8.58-10.49 | Foraminifers: 2 | 8.86 | ||||||||
| 3 | 237.54-269.11 | 8.3-11.4 | Foraminifers: 2 | 8.75 | ||||||||
| 165-999A-28X-5, 13-14 | 4 | 254.83 | 1 | 245.71-257.17 | 8.43-9.43 | Nannofossils: 1 | 9.23 | 8.93 | 4.26 | 4.67-13.19 | 3 | |
| 4 | 245.71-257.17 | 8.45-9.37 | Nannofossils: 1 | 9.18 | ||||||||
| 6 | 237.54-265.56 | 8.58-9.82 | Foraminifers: 2 | 9.26 | ||||||||
| 3 | 237.54-265.56 | 8.3-10.9 | Foraminifers: 2 | 9.72 | ||||||||
| 6 | 237.54 -269.11 | 8.58-10.49 | Foraminifers: 2 | 9.63 | ||||||||
| 3 | 237.54-269.11 | 8.3-11.4 | Foraminifers: 2 | 10.00 | ||||||||
| Chron C5n.1n (o) | 254.58-257.35 | Paleomagnetism 3* | 9.78 | |||||||||
| 165-998A-20X-1, 133-134 | 3 | 177.23 | 1 | 172.70-195.44 | 13.57-15.83 | Nannofossils: 1 | 14.02 | 13.94 | 0.82 | 13.12-14.76 | 2 | |
| 3 | 172.70-195.44 | 13.6-15.6 | Nannofossils: 1 | 14.00 | ||||||||
| 165-998A-21X-4, 79-80 | 6 | 190.79 | 1 | 172.70-195.44 | 13.57-15.83 | Nannofossils: 1 | 15.37 | 15.30 | 0.39 | 14.91-15.69 | 1 | |
| 3 | 172.70-195.44 | 13.6-15.6 | Nannofossils: 1 | 15.19 | ||||||||
| 165-999A-40X-1, 57-58 | 3 | 364.57 | 1 | 363.85-451.30 | 15.83-18.10 | Nannofossils: 1 | 15.85 | 16.23 | 3.07 | 13.16-19.30 | 3 | |
| 3 | 363.85-451.30 | 15.6-18.2 | Nannofossils: 1 | 15.62 | ||||||||
| 3 | 345.75-416.25 | 14.8-16.4 | Foraminifers: 2 | 15.23 | ||||||||
| 165-999A-41X-4, 41-42 | 7 | 378.61 | 1 | 363.85-451.30 | 15.83-18.10 | Nannofossils: 1 | 16.21 | 19.38 | 2.66 | 16.72-22.04 | 3? | |
| 3 | 363.85-451.30 | 15.6-18.2 | Nannofossils: 1 | 16.04 | ||||||||
| 3 | 345.75 -416.25 | 14.8-16.4 | Foraminifers: 2 | 15.55 | ||||||||
| 165-999A-45X-2, 94-95 | 5 | 414.54 | 1 | 363.85-451.30 | 15.83-18.10 | Nannofossils: 1 | 17.15 | 19.29 | 2.65 | 16.64-21.94 | 3? | |
| 3 | 363.85-451.30 | 15.6-18.2 | Nannofossils: 1 | 17.11 | ||||||||
| 3 | 345.75-416.25 | 14.8-16.4 | Foraminifers: 2 | 16.36 | ||||||||
| 165-999A-48X-6, 42-43 | 6 | 449.02 | 1 | 363.85-451.30 | 15.83-18.10 | Nannofossils: 1 | 18.04 | 17.98 | 0.5 | 17.48-18.48 | 1 | |
| 3 | 363.85-451.30 | 15.6-18.2 | Nannofossils: 1 | 18.13 | ||||||||
| 3 | 416.25-454.14 | 16.4-17.3 | Foraminifers: 2 | 17.18 | ||||||||
| 165-999A-48X-6, 42-43 (sanidine) | 16 | 16.36 | 0.31 | 16.05-16.67 | 3? | |||||||
| 165-1000B-14R-2, 139-140 | 6 | 611.77 | 1 | 557.35-643.30 | 15.83-18.1 | Nannofossils: 3* | 17.27 | 18.31 | 0.33 | 17.98-18.64 | 3? | |
| 3 | 557.35-643.30 | 15.6-18.2 | Nannofossils: 3* | 17.25 | ||||||||
| 3 | 590.05-633.40 | 16.4-17.3 | Foraminifers: 3 | 16.85 | ||||||||
| 165-1000B-16R-5, 84-85 | 9 | 635.44 | 1 | 557.35-643.30 | 15.83-18.1 | Nannofossils: 3* | 17.89 | 17.50 | 0.15 | 17.35-17.65 | 1? | |
| 3 | 557.35-643.30 | 15.6-18.2 | Nannofossils: 3* | 17.96 | ||||||||
| 165-1000B-19R-2, 99-101 | 13 | 659.89 | 1 | 643.30-668.90 | 18.1-19.7 | Nannofossils: 3* | 19.14 | 17.02 | 0.17 | 16.85-17.19 | 3? | |
| 3 | 643.30-668.90 | 18.2-19.2 | Nannofossils: 3* | 18.85 | ||||||||
| 165-998A-27X-1, 120-122 | 8 | 244.40 | 1 | 242.56-244.95 | 18.10-18.40 | Nannofossils: 1 | 18.33 | 18.16 | 0.21 | 17.95-18.37 | 1 | |
| 3 | 242.56-244.95 | 18.2-18.3 | Nannofossils: 1 | 18.28 | ||||||||
| 165-998A-29X-3, 68-69 | 4 | 266.18 | 1 | 257.65-330.01 | 19.70-23.80 | Nannofossils: 1 | 20.18 | 22.97 | 0.36 | 22.61-23.33 | 3? | |
| 3 | 257.65-330.01 | 19.2-23.8 | Nannofossils: 1 | 19.74 | ||||||||
| 165-998A-29X-3, 68-69 | 3 | 12.79 | 0.48 | 4 | ||||||||
| 165-999B-7R-CC, 13-14 | 5 | 591.70 | 3 | 480.10-605.96 | 19.2-23.8 | Nannofossils: 3* | 23.28 | 23.44 | 1.79 | 21.65-25.23 | 3 | |
| 3 | 454.38-605.96 | 17.3-23.8 | Foraminifers: 3 | 23.19 | ||||||||
| 165-999B-15R-2, 45-46 | 8 | 661.05 | 3 | 654.42-680.26 | 27.5-29.9 | Nannofossils: 3* | 28.12 | 27.21 | 0.79 | 26.42-28.00 | 2? | |
| 3 | 605.96-710.92 | 23.8-32.0 | Foraminifers: 3 | 28.10 | ||||||||
| 165-998A-52X-1, 128-129 | 1 | 484.98 | 3 | 448.39-486.98 | 27.5-29.9 | Nannofossils: 3* | 29.78 | 30.70 | 18.60 | 12.1-49.3 | 3 | |
| 3 | 448.39-514.25 | 27.5-31.5 | Nannofossils: 3* | 29.72 | ||||||||
| 3 | 443.81-494.47 | 27.1-28.5 | Foraminifers: 3 | 28.20 | ||||||||
| 165-998B-1R-7, 53-54 | 6 | 567.30 | 3 | 566.95-576.55 | 32.3-32.8 | Nannofossils: 3* | 32.32 | 31.67 | 1.30 | 30.37-32.97 | 2 | |
| 3 | 514.25-586.00 | 31.5-34.2 | Nannofossils: 3* | 33.50 | ||||||||
| 165-999B-47R-6, 4-5 | 2 | 937.54 | 3 | 918.44-949.89 | 49.7-52.85 | Nannofossils: 3* | 51.61 | 48.61 | 1.15 | 47.46-49.76 | 3? | |
| 3 | 864.39-949.89 | 46.1-52.85 | Nannofossils: 3* | 51.87 | ||||||||
| 3 | 843.60-951.84 | 43.6-52.3 | Foraminifers: 3 | 51.15 | ||||||||
| 165-999B-48R-3, 6-7 | 20 | 942.66 | 3 | 918.44-949.89 | 49.7-52.85 | Nannofossils: 3* | 52.13 | 52.47 | 0.92 | 51.55-53.39 | 2 | |
| 3 | 864.39-949.89 | 46.1-52.85 | Nannofossils: 3* | 52.28 | ||||||||
| 3 | 843.60-951.84 | 43.6-52.3 | Foraminifers: 3 | 51.56 | ||||||||
| 165-1001A-26R-2, 63-64 | 3 | 229.93 | 3 | 169.89-234.10 | 52.85-55.3 | Nannofossils: 3* | 55.14 | 60.14 | 1.57 | 58.57-61.71 | 3?(4?) | |
| 3 | 169.89-267.79 | 52.85-56.2 | Nannofossils: 3* | 54.90 | ||||||||
| 7 | 204.20-259.50 | 53.347-55.904 | Paleomagnetism 3* | 54.54 | ||||||||
| 165-1001B-6R-3, 130-131 | 2 | 238.90 | 3 | 232.31-262.29 | 55.3-56.2 | Nannofossils: 3* | 55.50 | 81.04 | 2.88 | 78.16-83.92 | 4 | |
| 3 | 232.31-285.94 | 55.3-57.5 | Nannofossils: 3* | 55.57 | ||||||||
| 7 | 204.20-259.50 | 53.347-55.904 | Paleomagnetism 3* | 54.95 | ||||||||
| 165-1001A-36R-3, 70-71 | 8 | 327.50 | 3 | 296.77-327.63 | 58.4-59.7 | Nannofossils: 3* | 59.69 | 74.78 | 0.66 | 74.12-75.44 | 4 | |
| 7 | 291.90-331.35 | 57.911-60.920 | Paleomagnetism 3* | 60.63 | ||||||||
Notes: Age model: 1 = ages of Kameo and Bralower (Chap. 1, this volume), includes ages of Raffi and Flores (1995) for interval 5-17 Ma; 2 = ages of I. Raffi (unpubl. data, 1999); 3 = ages of Berggren et al. (1995a, 1995b); 4 = ages of Shackleton et al. (1995); 5 = ages of Backman and Raffi (1997); 6 = ages of Chaisson and Pearson (1997) and Pearson and Chaisson (1997); and 7 = magnetochron ages as summarized in Sigurdsson, Leckie, Acton, et al. (1997). Biostratigraphic sources: 1 = high-resolution calcareous nannofossil biostratigraphy of Holes 998A, 999A, and 1000A from Kameo and Bralower (Chap. 1, this volume); 2 = high-resolution planktonic foraminiferal biostratigraphy of Hole 999A from Chaisson and D'Hondt (Chap. 2, this volume); 3 = low- to high(*)-resolution shipboard biostratigraphy and paleomagnetism from Sigurdsson, Leckie, Acton, et al. (1997); 4 = this study; and boldface = within error. Tephra rank: 1 = congruent age with small error (<0.5 m.y.); 2 = congruent age with larger error (0.5-1.5 m.y.); 3 = reasonable mean but very large error (>1.5 m.y.), or suspect age; 4 = incongruent age (diagenetic alteration or sedimentary reworking); boldface = radiometric ages in good agreement with biostratigraphy and with small errors; and italics = radiometric ages from diagenetically altered or reworked mineral grains.