|
Event Datum
|
North Pacific Diatom zone boundary
|
Age (Ma)*†
|
Age (Ma)‡
|
Interval
|
Depth (mbsf)
|
Interval
|
Depth (mbsf)
|
Interval
|
Depth (mbsf)
|
|---|---|---|---|---|---|---|---|---|---|
| 186-1150A- | 186-1150B- | 186-1151A- | |||||||
| LO P. curvirostris | NPD11/12 | 0.30 | 0.3 | 5H-CC/6H-CC | 46.33/55.73 | ND | ND | ND | ND |
| LO A. oculatus | NPD10/11 | 1.01-1.46 | 1.0 | 11H-CC/12H-CC | 102.66/112.15 | ND | ND | 3R-CC/4R-CC | 92.50/99.51 |
| LO N. koizumii | NPD9/10 | 2.0 | 2.0 | 15X-CC/16X-CC | 130.20/139.58 | ND | ND | 5R-CC/6R-CC | 105.90/118.07 |
| LCsO N. kamtschatica | NPD8/9 | 2.61-2.68 | 2.6-2.7 | 21X-CC/22X-CC | 192.01/202.94 | ND | ND | 11R-CC/12R-CC | 168.86/179.96 |
| FO N. koizumii | NPD7Bb/8 | 3.53-3.95 | 3.5-3.9 | 27X-CC/28X-CC | 251.16/260.33 | ND | ND | 14R-CC/15R-CC | 199.19/208.87 |
| FO T. oestrupii | NPD7Ba/7Bb | 5.49 | 5.5 | ND | ND | ND | ND | ND | ND |
| FCsO N. kamtschatica | NPD7A/7Ba | 6.4 | 6.4 | ND | ND | 21R-CC/22R-CC | 898.32/910.67 | 77R-CC/79R-CC | 800.62/816.95 |
| LCO T. schraderi | NPD6B/7A | 7.6 | 7.6 | ND | ND | 35R-CC/36R-CC | 1031.50/1044.73 | 79R-CC/80R-CC | 816.95/834.47 |
| LCsO D. simonsenii | NPD6A/6B | 8.6 | 8.5 | ND | ND | 40R-CC/41R-CC | 1079.21/1094.47 | 90R-CC/91R-CC | 926.10/939.54 |
| LO D. dimorpha | NPD5D/6A | 9.16 | 9.2 | ND | ND | 42R-CC/43R-CC | 1103.87/1111.28 | 90R-CC/91R-CC | 926.10/939.54 |
| FO D. dimorpha | NPD5C/5D | 9.9 | 10.0 | ND | ND | 48R-CC/49R-CC | 1157.71/1170.57 | 95R-CC/99R-CC | 970.00/1009.53 |
| LCO D. praedimorpha | NPD5B/5C | 11.5 | 11.5 | ND | ND | Below 50R-CC | Below 1180.23 | ND | ND |
| FO D. praedimorpha | NPD5A/5B | 12.9 | 12.9 | ND | ND | ND | ND | ND | ND |
| FCO D. simonsenii | NPD4Bb/5A | 13.1 | 13.1 | ND | ND | ND | ND | 99R-CC/101R-CC | 1009.53/1028.78 |
| FO D. simonsenii | NPD4Ba/4Bb | 14.4-14.6 | 14.5-14.9 | ND | ND | ND | ND | 99R-CC/101R-CC | 1009.53/1028.78 |
| FO D. hyalina | NPD4A/4Ba | 14.9 | 14.9 | ND | ND | ND | ND | 103R-CC/104R-CC | 1048.85/1061.21 |
| FO D. lauta | NPD3B/4A | 15.9 | 15.9 | ND | ND | ND | ND | 107R-CC/108R-CC | 1093.97/1104.08 |
| FO D. praelauta | NPD3A/3B | 16.3 | 16.3 | ND | ND | ND | ND | Below 109R-CC | Below 1113.46 |
Notes: * = Motoyama and Maruyama (1988), † = Maruyama (2000), ‡ = Yanagisawa and Akiba (1998). FO = first occurrence, LO = last occurrence, FCO = first common occurrence, LCO = last common occurrence, FCsO = first consistent occurrence, LCsO = last consistent occurrence. ND = no data. The boundary between Subzone NPD4Bb and Zone NPD5A can be also recognized by the LCO Denticulopsis hyalina. A taxonomic problem prohibits the FO T. oestrupii from defining the subzonal boundary between NPD7Ba and NPD7b among all of three holes. Indefinite zones of NPD4Bb, 5A, 5B, 5C, and 6A in Hole 1151A indicate the low sedimentation rate or the presence of some hiatuses in a stratigraphic sequence.